linux-arch.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure
@ 2018-09-25 17:16 Eric W. Biederman
  2018-09-25 17:16 ` Eric W. Biederman
                   ` (6 more replies)
  0 siblings, 7 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:16 UTC (permalink / raw)
  To: linux-kernel; +Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds


I am posting these patches for review in the hopes that if I have missed
something someone else might catch it.  If no issues turn up I intend to
merge these patches through my siginfo branch.

This set of patches make a few small ABI changes to areas of the linux
ABI where as far as I can determine no one cares.

- sigqueueinfo in all it's variants now fails if si_signo != sig
  instead of quietly changing si_signo.

  The deep issue is that the change happens after the code has already
  verified in copy_siginfom_from_user that the si_signo and si_code
  combination is meaningful.

- copy_siginfo_from_user now fails if the trailing bytes of siginfo
  are not 0, when the signal number and si_code combination is not
  recognized.

  If the si_signo and si_code combination is recognized we know any
  trailing bytes are meaningless as the meaningful bytes are in siginfo.

  This check is to allow people to define new siginfo union members and
  that will fail on older kernels.  The check makes it as safe as
  possible to have a kernel_siginfo that is smaller than the ABI defined
  siginfo that the kernel reads from and writes to userspace.

The net effect of this change is a kernel that only uses 48 bytes for
siginfo internally when the ABI defines siginfo to be 128 bytes.

The first EMT_TAGOVF change is not necesssary to strinking siginfo.

Eric W. Biederman (6):
      signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
      signal: Fail sigqueueinfo if si_signo != sig
      signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
      signal: Introduce copy_siginfo_from_user and use it's return value
      signal: Distinguish between kernel_siginfo and siginfo
      signal: Use a smaller struct siginfo in the kernel

 arch/alpha/include/uapi/asm/siginfo.h   |   1 -
 arch/arm64/include/uapi/asm/Kbuild      |   1 +
 arch/arm64/include/uapi/asm/siginfo.h   |  24 ---
 arch/ia64/include/uapi/asm/siginfo.h    |   2 -
 arch/mips/include/uapi/asm/siginfo.h    |  11 --
 arch/parisc/include/uapi/asm/Kbuild     |   1 +
 arch/parisc/include/uapi/asm/siginfo.h  |  11 --
 arch/powerpc/include/uapi/asm/Kbuild    |   1 +
 arch/powerpc/include/uapi/asm/siginfo.h |  18 ---
 arch/riscv/include/uapi/asm/Kbuild      |   1 +
 arch/riscv/include/uapi/asm/siginfo.h   |  24 ---
 arch/s390/include/uapi/asm/Kbuild       |   1 +
 arch/s390/include/uapi/asm/siginfo.h    |  17 ---
 arch/sparc/include/uapi/asm/siginfo.h   |   7 -
 arch/x86/include/asm/compat.h           |   2 +-
 arch/x86/include/uapi/asm/siginfo.h     |   2 -
 drivers/usb/core/devio.c                |   4 +-
 fs/binfmt_elf.c                         |   6 +-
 fs/coredump.c                           |   2 +-
 fs/fcntl.c                              |   2 +-
 fs/signalfd.c                           |   6 +-
 include/linux/binfmts.h                 |   2 +-
 include/linux/compat.h                  |   4 +-
 include/linux/coredump.h                |   4 +-
 include/linux/lsm_hooks.h               |   4 +-
 include/linux/posix-timers.h            |   2 +-
 include/linux/ptrace.h                  |   2 +-
 include/linux/sched.h                   |   2 +-
 include/linux/sched/signal.h            |  18 +--
 include/linux/security.h                |   6 +-
 include/linux/signal.h                  |  16 +-
 include/linux/signal_types.h            |   8 +-
 include/trace/events/signal.h           |   4 +-
 include/uapi/asm-generic/siginfo.h      | 193 ++++++++++++-----------
 ipc/mqueue.c                            |   2 +-
 kernel/ptrace.c                         |  22 ++-
 kernel/seccomp.c                        |   6 +-
 kernel/signal.c                         | 263 ++++++++++++++++++++++----------
 kernel/time/posix-timers.c              |   2 +-
 security/apparmor/lsm.c                 |   2 +-
 security/security.c                     |   2 +-
 security/selinux/hooks.c                |   2 +-
 security/smack/smack_lsm.c              |   2 +-
 43 files changed, 356 insertions(+), 356 deletions(-)

Eric

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure
  2018-09-25 17:16 [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure Eric W. Biederman
@ 2018-09-25 17:16 ` Eric W. Biederman
  2018-09-25 17:19 ` [REVIEW][PATCH 1/6] signal/sparc: Move EMT_TAGOVF into the generic siginfo.h Eric W. Biederman
                   ` (5 subsequent siblings)
  6 siblings, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:16 UTC (permalink / raw)
  To: linux-kernel; +Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds


I am posting these patches for review in the hopes that if I have missed
something someone else might catch it.  If no issues turn up I intend to
merge these patches through my siginfo branch.

This set of patches make a few small ABI changes to areas of the linux
ABI where as far as I can determine no one cares.

- sigqueueinfo in all it's variants now fails if si_signo != sig
  instead of quietly changing si_signo.

  The deep issue is that the change happens after the code has already
  verified in copy_siginfom_from_user that the si_signo and si_code
  combination is meaningful.

- copy_siginfo_from_user now fails if the trailing bytes of siginfo
  are not 0, when the signal number and si_code combination is not
  recognized.

  If the si_signo and si_code combination is recognized we know any
  trailing bytes are meaningless as the meaningful bytes are in siginfo.

  This check is to allow people to define new siginfo union members and
  that will fail on older kernels.  The check makes it as safe as
  possible to have a kernel_siginfo that is smaller than the ABI defined
  siginfo that the kernel reads from and writes to userspace.

The net effect of this change is a kernel that only uses 48 bytes for
siginfo internally when the ABI defines siginfo to be 128 bytes.

The first EMT_TAGOVF change is not necesssary to strinking siginfo.

Eric W. Biederman (6):
      signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
      signal: Fail sigqueueinfo if si_signo != sig
      signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
      signal: Introduce copy_siginfo_from_user and use it's return value
      signal: Distinguish between kernel_siginfo and siginfo
      signal: Use a smaller struct siginfo in the kernel

 arch/alpha/include/uapi/asm/siginfo.h   |   1 -
 arch/arm64/include/uapi/asm/Kbuild      |   1 +
 arch/arm64/include/uapi/asm/siginfo.h   |  24 ---
 arch/ia64/include/uapi/asm/siginfo.h    |   2 -
 arch/mips/include/uapi/asm/siginfo.h    |  11 --
 arch/parisc/include/uapi/asm/Kbuild     |   1 +
 arch/parisc/include/uapi/asm/siginfo.h  |  11 --
 arch/powerpc/include/uapi/asm/Kbuild    |   1 +
 arch/powerpc/include/uapi/asm/siginfo.h |  18 ---
 arch/riscv/include/uapi/asm/Kbuild      |   1 +
 arch/riscv/include/uapi/asm/siginfo.h   |  24 ---
 arch/s390/include/uapi/asm/Kbuild       |   1 +
 arch/s390/include/uapi/asm/siginfo.h    |  17 ---
 arch/sparc/include/uapi/asm/siginfo.h   |   7 -
 arch/x86/include/asm/compat.h           |   2 +-
 arch/x86/include/uapi/asm/siginfo.h     |   2 -
 drivers/usb/core/devio.c                |   4 +-
 fs/binfmt_elf.c                         |   6 +-
 fs/coredump.c                           |   2 +-
 fs/fcntl.c                              |   2 +-
 fs/signalfd.c                           |   6 +-
 include/linux/binfmts.h                 |   2 +-
 include/linux/compat.h                  |   4 +-
 include/linux/coredump.h                |   4 +-
 include/linux/lsm_hooks.h               |   4 +-
 include/linux/posix-timers.h            |   2 +-
 include/linux/ptrace.h                  |   2 +-
 include/linux/sched.h                   |   2 +-
 include/linux/sched/signal.h            |  18 +--
 include/linux/security.h                |   6 +-
 include/linux/signal.h                  |  16 +-
 include/linux/signal_types.h            |   8 +-
 include/trace/events/signal.h           |   4 +-
 include/uapi/asm-generic/siginfo.h      | 193 ++++++++++++-----------
 ipc/mqueue.c                            |   2 +-
 kernel/ptrace.c                         |  22 ++-
 kernel/seccomp.c                        |   6 +-
 kernel/signal.c                         | 263 ++++++++++++++++++++++----------
 kernel/time/posix-timers.c              |   2 +-
 security/apparmor/lsm.c                 |   2 +-
 security/security.c                     |   2 +-
 security/selinux/hooks.c                |   2 +-
 security/smack/smack_lsm.c              |   2 +-
 43 files changed, 356 insertions(+), 356 deletions(-)

Eric

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 1/6] signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
  2018-09-25 17:16 [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure Eric W. Biederman
  2018-09-25 17:16 ` Eric W. Biederman
@ 2018-09-25 17:19 ` Eric W. Biederman
  2018-09-25 17:19   ` Eric W. Biederman
  2018-09-25 17:19 ` [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig Eric W. Biederman
                   ` (4 subsequent siblings)
  6 siblings, 1 reply; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

When moving all of the architectures specific si_codes into
siginfo.h, I apparently overlooked EMT_TAGOVF.  Move it now.

Remove the now redundant test in siginfo_layout for SIGEMT
as now NSIGEMT is always defined.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/sparc/include/uapi/asm/siginfo.h | 6 ------
 include/uapi/asm-generic/siginfo.h    | 6 ++++++
 kernel/signal.c                       | 2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/sparc/include/uapi/asm/siginfo.h b/arch/sparc/include/uapi/asm/siginfo.h
index e7049550ac82..6c820ea0813b 100644
--- a/arch/sparc/include/uapi/asm/siginfo.h
+++ b/arch/sparc/include/uapi/asm/siginfo.h
@@ -17,10 +17,4 @@
 
 #define SI_NOINFO	32767		/* no information in siginfo_t */
 
-/*
- * SIGEMT si_codes
- */
-#define EMT_TAGOVF	1	/* tag overflow */
-#define NSIGEMT		1
-
 #endif /* _UAPI__SPARC_SIGINFO_H */
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 80e2a7227205..1811b8101937 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -285,6 +285,12 @@ typedef struct siginfo {
 #define SYS_SECCOMP	1	/* seccomp triggered */
 #define NSIGSYS		1
 
+/*
+ * SIGEMT si_codes
+ */
+#define EMT_TAGOVF	1	/* tag overflow */
+#define NSIGEMT		1
+
 /*
  * sigevent definitions
  * 
diff --git a/kernel/signal.c b/kernel/signal.c
index e16278710b36..7b49c31d3fdb 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2856,7 +2856,7 @@ enum siginfo_layout siginfo_layout(int sig, int si_code)
 			[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
 			[SIGBUS]  = { NSIGBUS,  SIL_FAULT },
 			[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
-#if defined(SIGEMT) && defined(NSIGEMT)
+#if defined(SIGEMT)
 			[SIGEMT]  = { NSIGEMT,  SIL_FAULT },
 #endif
 			[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 1/6] signal/sparc: Move EMT_TAGOVF into the generic siginfo.h
  2018-09-25 17:19 ` [REVIEW][PATCH 1/6] signal/sparc: Move EMT_TAGOVF into the generic siginfo.h Eric W. Biederman
@ 2018-09-25 17:19   ` Eric W. Biederman
  0 siblings, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

When moving all of the architectures specific si_codes into
siginfo.h, I apparently overlooked EMT_TAGOVF.  Move it now.

Remove the now redundant test in siginfo_layout for SIGEMT
as now NSIGEMT is always defined.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/sparc/include/uapi/asm/siginfo.h | 6 ------
 include/uapi/asm-generic/siginfo.h    | 6 ++++++
 kernel/signal.c                       | 2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/sparc/include/uapi/asm/siginfo.h b/arch/sparc/include/uapi/asm/siginfo.h
index e7049550ac82..6c820ea0813b 100644
--- a/arch/sparc/include/uapi/asm/siginfo.h
+++ b/arch/sparc/include/uapi/asm/siginfo.h
@@ -17,10 +17,4 @@
 
 #define SI_NOINFO	32767		/* no information in siginfo_t */
 
-/*
- * SIGEMT si_codes
- */
-#define EMT_TAGOVF	1	/* tag overflow */
-#define NSIGEMT		1
-
 #endif /* _UAPI__SPARC_SIGINFO_H */
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 80e2a7227205..1811b8101937 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -285,6 +285,12 @@ typedef struct siginfo {
 #define SYS_SECCOMP	1	/* seccomp triggered */
 #define NSIGSYS		1
 
+/*
+ * SIGEMT si_codes
+ */
+#define EMT_TAGOVF	1	/* tag overflow */
+#define NSIGEMT		1
+
 /*
  * sigevent definitions
  * 
diff --git a/kernel/signal.c b/kernel/signal.c
index e16278710b36..7b49c31d3fdb 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2856,7 +2856,7 @@ enum siginfo_layout siginfo_layout(int sig, int si_code)
 			[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
 			[SIGBUS]  = { NSIGBUS,  SIL_FAULT },
 			[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
-#if defined(SIGEMT) && defined(NSIGEMT)
+#if defined(SIGEMT)
 			[SIGEMT]  = { NSIGEMT,  SIL_FAULT },
 #endif
 			[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig
  2018-09-25 17:16 [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure Eric W. Biederman
  2018-09-25 17:16 ` Eric W. Biederman
  2018-09-25 17:19 ` [REVIEW][PATCH 1/6] signal/sparc: Move EMT_TAGOVF into the generic siginfo.h Eric W. Biederman
@ 2018-09-25 17:19 ` Eric W. Biederman
  2018-09-25 17:19   ` Eric W. Biederman
  2018-10-05  6:06   ` Andrei Vagin
  2018-09-25 17:19 ` [REVIEW][PATCH 3/6] signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE Eric W. Biederman
                   ` (3 subsequent siblings)
  6 siblings, 2 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

The kernel needs to validate that the contents of struct siginfo make
sense as siginfo is copied into the kernel, so that the proper union
members can be put in the appropriate locations.  The field si_signo
is a fundamental part of that validation.  As such changing the
contents of si_signo after the validation make no sense and can result
in nonsense values in the kernel.

As such simply fail if someone is silly enough to set si_signo out of
sync with the signal number passed to sigqueueinfo.

I don't expect a problem as glibc's sigqueue implementation sets
"si_signo = sig" and CRIU just returns to the kernel what the kernel
gave to it.

If there is some application that calls sigqueueinfo directly that has
a problem with this added sanity check we can revisit this when we see
what kind of crazy that application is doing.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 kernel/signal.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 7b49c31d3fdb..e445b0a63faa 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3306,7 +3306,8 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
 	    (task_pid_vnr(current) != pid))
 		return -EPERM;
 
-	info->si_signo = sig;
+	if (info->si_signo != sig)
+		return -EINVAL;
 
 	/* POSIX.1b doesn't mention process groups.  */
 	return kill_proc_info(sig, info, pid);
@@ -3354,7 +3355,8 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
 	    (task_pid_vnr(current) != pid))
 		return -EPERM;
 
-	info->si_signo = sig;
+	if (info->si_signo != sig)
+		return -EINVAL;
 
 	return do_send_specific(tgid, pid, sig, info);
 }
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig
  2018-09-25 17:19 ` [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig Eric W. Biederman
@ 2018-09-25 17:19   ` Eric W. Biederman
  2018-10-05  6:06   ` Andrei Vagin
  1 sibling, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

The kernel needs to validate that the contents of struct siginfo make
sense as siginfo is copied into the kernel, so that the proper union
members can be put in the appropriate locations.  The field si_signo
is a fundamental part of that validation.  As such changing the
contents of si_signo after the validation make no sense and can result
in nonsense values in the kernel.

As such simply fail if someone is silly enough to set si_signo out of
sync with the signal number passed to sigqueueinfo.

I don't expect a problem as glibc's sigqueue implementation sets
"si_signo = sig" and CRIU just returns to the kernel what the kernel
gave to it.

If there is some application that calls sigqueueinfo directly that has
a problem with this added sanity check we can revisit this when we see
what kind of crazy that application is doing.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 kernel/signal.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 7b49c31d3fdb..e445b0a63faa 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3306,7 +3306,8 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
 	    (task_pid_vnr(current) != pid))
 		return -EPERM;
 
-	info->si_signo = sig;
+	if (info->si_signo != sig)
+		return -EINVAL;
 
 	/* POSIX.1b doesn't mention process groups.  */
 	return kill_proc_info(sig, info, pid);
@@ -3354,7 +3355,8 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
 	    (task_pid_vnr(current) != pid))
 		return -EPERM;
 
-	info->si_signo = sig;
+	if (info->si_signo != sig)
+		return -EINVAL;
 
 	return do_send_specific(tgid, pid, sig, info);
 }
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 3/6] signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
  2018-09-25 17:16 [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure Eric W. Biederman
                   ` (2 preceding siblings ...)
  2018-09-25 17:19 ` [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig Eric W. Biederman
@ 2018-09-25 17:19 ` Eric W. Biederman
  2018-09-25 17:19   ` Eric W. Biederman
  2018-09-25 17:19 ` [REVIEW][PATCH 4/6] signal: Introduce copy_siginfo_from_user and use it's return value Eric W. Biederman
                   ` (2 subsequent siblings)
  6 siblings, 1 reply; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

Rework the defintion of struct siginfo so that the array padding
struct siginfo to SI_MAX_SIZE can be placed in a union along side of
the rest of the struct siginfo members.  The result is that we no
longer need the __ARCH_SI_PREAMBLE_SIZE or SI_PAD_SIZE definitions.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/alpha/include/uapi/asm/siginfo.h   |   1 -
 arch/arm64/include/uapi/asm/Kbuild      |   1 +
 arch/arm64/include/uapi/asm/siginfo.h   |  24 ---
 arch/ia64/include/uapi/asm/siginfo.h    |   2 -
 arch/mips/include/uapi/asm/siginfo.h    |  11 --
 arch/parisc/include/uapi/asm/Kbuild     |   1 +
 arch/parisc/include/uapi/asm/siginfo.h  |  11 --
 arch/powerpc/include/uapi/asm/Kbuild    |   1 +
 arch/powerpc/include/uapi/asm/siginfo.h |  18 ---
 arch/riscv/include/uapi/asm/Kbuild      |   1 +
 arch/riscv/include/uapi/asm/siginfo.h   |  24 ---
 arch/s390/include/uapi/asm/Kbuild       |   1 +
 arch/s390/include/uapi/asm/siginfo.h    |  17 ---
 arch/sparc/include/uapi/asm/siginfo.h   |   1 -
 arch/x86/include/uapi/asm/siginfo.h     |   2 -
 include/uapi/asm-generic/siginfo.h      | 187 ++++++++++++------------
 kernel/signal.c                         |   3 -
 17 files changed, 99 insertions(+), 207 deletions(-)
 delete mode 100644 arch/arm64/include/uapi/asm/siginfo.h
 delete mode 100644 arch/parisc/include/uapi/asm/siginfo.h
 delete mode 100644 arch/powerpc/include/uapi/asm/siginfo.h
 delete mode 100644 arch/riscv/include/uapi/asm/siginfo.h
 delete mode 100644 arch/s390/include/uapi/asm/siginfo.h

diff --git a/arch/alpha/include/uapi/asm/siginfo.h b/arch/alpha/include/uapi/asm/siginfo.h
index db3f0138536f..6e1a2af2f962 100644
--- a/arch/alpha/include/uapi/asm/siginfo.h
+++ b/arch/alpha/include/uapi/asm/siginfo.h
@@ -2,7 +2,6 @@
 #ifndef _ALPHA_SIGINFO_H
 #define _ALPHA_SIGINFO_H
 
-#define __ARCH_SI_PREAMBLE_SIZE		(4 * sizeof(int))
 #define __ARCH_SI_TRAPNO
 
 #include <asm-generic/siginfo.h>
diff --git a/arch/arm64/include/uapi/asm/Kbuild b/arch/arm64/include/uapi/asm/Kbuild
index 198afbf0688f..6c5adf458690 100644
--- a/arch/arm64/include/uapi/asm/Kbuild
+++ b/arch/arm64/include/uapi/asm/Kbuild
@@ -19,3 +19,4 @@ generic-y += swab.h
 generic-y += termbits.h
 generic-y += termios.h
 generic-y += types.h
+generic-y += siginfo.h
diff --git a/arch/arm64/include/uapi/asm/siginfo.h b/arch/arm64/include/uapi/asm/siginfo.h
deleted file mode 100644
index 574d12f86039..000000000000
--- a/arch/arm64/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-/*
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_SIGINFO_H
-#define __ASM_SIGINFO_H
-
-#define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
-
-#include <asm-generic/siginfo.h>
-
-#endif
diff --git a/arch/ia64/include/uapi/asm/siginfo.h b/arch/ia64/include/uapi/asm/siginfo.h
index 52b5af424511..796af1ccaa7e 100644
--- a/arch/ia64/include/uapi/asm/siginfo.h
+++ b/arch/ia64/include/uapi/asm/siginfo.h
@@ -9,8 +9,6 @@
 #define _UAPI_ASM_IA64_SIGINFO_H
 
 
-#define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
-
 #include <asm-generic/siginfo.h>
 
 #define si_imm		_sifields._sigfault._imm	/* as per UNIX SysV ABI spec */
diff --git a/arch/mips/include/uapi/asm/siginfo.h b/arch/mips/include/uapi/asm/siginfo.h
index 262504bd59a5..c34c7eef0a1c 100644
--- a/arch/mips/include/uapi/asm/siginfo.h
+++ b/arch/mips/include/uapi/asm/siginfo.h
@@ -14,17 +14,6 @@
 #define __ARCH_SIGEV_PREAMBLE_SIZE (sizeof(long) + 2*sizeof(int))
 #undef __ARCH_SI_TRAPNO /* exception code needs to fill this ...  */
 
-/*
- * Careful to keep union _sifields from shifting ...
- */
-#if _MIPS_SZLONG == 32
-#define __ARCH_SI_PREAMBLE_SIZE (3 * sizeof(int))
-#elif _MIPS_SZLONG == 64
-#define __ARCH_SI_PREAMBLE_SIZE (4 * sizeof(int))
-#else
-#error _MIPS_SZLONG neither 32 nor 64
-#endif
-
 #define __ARCH_HAS_SWAPPED_SIGINFO
 
 #include <asm-generic/siginfo.h>
diff --git a/arch/parisc/include/uapi/asm/Kbuild b/arch/parisc/include/uapi/asm/Kbuild
index 286ef5a5904b..adb5c64831c7 100644
--- a/arch/parisc/include/uapi/asm/Kbuild
+++ b/arch/parisc/include/uapi/asm/Kbuild
@@ -7,3 +7,4 @@ generic-y += kvm_para.h
 generic-y += param.h
 generic-y += poll.h
 generic-y += resource.h
+generic-y += siginfo.h
diff --git a/arch/parisc/include/uapi/asm/siginfo.h b/arch/parisc/include/uapi/asm/siginfo.h
deleted file mode 100644
index 4a1062e05aaf..000000000000
--- a/arch/parisc/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,11 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-#ifndef _PARISC_SIGINFO_H
-#define _PARISC_SIGINFO_H
-
-#if defined(__LP64__)
-#define __ARCH_SI_PREAMBLE_SIZE   (4 * sizeof(int))
-#endif
-
-#include <asm-generic/siginfo.h>
-
-#endif
diff --git a/arch/powerpc/include/uapi/asm/Kbuild b/arch/powerpc/include/uapi/asm/Kbuild
index 1a6ed5919ffd..a658091a19f9 100644
--- a/arch/powerpc/include/uapi/asm/Kbuild
+++ b/arch/powerpc/include/uapi/asm/Kbuild
@@ -7,3 +7,4 @@ generic-y += poll.h
 generic-y += resource.h
 generic-y += sockios.h
 generic-y += statfs.h
+generic-y += siginfo.h
diff --git a/arch/powerpc/include/uapi/asm/siginfo.h b/arch/powerpc/include/uapi/asm/siginfo.h
deleted file mode 100644
index 1d51d9b88221..000000000000
--- a/arch/powerpc/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
-#ifndef _ASM_POWERPC_SIGINFO_H
-#define _ASM_POWERPC_SIGINFO_H
-
-/*
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-
-#ifdef __powerpc64__
-#    define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
-#endif
-
-#include <asm-generic/siginfo.h>
-
-#endif	/* _ASM_POWERPC_SIGINFO_H */
diff --git a/arch/riscv/include/uapi/asm/Kbuild b/arch/riscv/include/uapi/asm/Kbuild
index 7e91f4850475..5511b9918131 100644
--- a/arch/riscv/include/uapi/asm/Kbuild
+++ b/arch/riscv/include/uapi/asm/Kbuild
@@ -26,3 +26,4 @@ generic-y += swab.h
 generic-y += termbits.h
 generic-y += termios.h
 generic-y += types.h
+generic-y += siginfo.h
diff --git a/arch/riscv/include/uapi/asm/siginfo.h b/arch/riscv/include/uapi/asm/siginfo.h
deleted file mode 100644
index f96849aac662..000000000000
--- a/arch/riscv/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * Copyright (C) 2012 ARM Ltd.
- * Copyright (C) 2016 SiFive, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_SIGINFO_H
-#define __ASM_SIGINFO_H
-
-#define __ARCH_SI_PREAMBLE_SIZE	(__SIZEOF_POINTER__ == 4 ? 12 : 16)
-
-#include <asm-generic/siginfo.h>
-
-#endif
diff --git a/arch/s390/include/uapi/asm/Kbuild b/arch/s390/include/uapi/asm/Kbuild
index e364873e0d10..dc38a90cf091 100644
--- a/arch/s390/include/uapi/asm/Kbuild
+++ b/arch/s390/include/uapi/asm/Kbuild
@@ -18,3 +18,4 @@ generic-y += shmbuf.h
 generic-y += sockios.h
 generic-y += swab.h
 generic-y += termbits.h
+generic-y += siginfo.h
\ No newline at end of file
diff --git a/arch/s390/include/uapi/asm/siginfo.h b/arch/s390/include/uapi/asm/siginfo.h
deleted file mode 100644
index 6984820f2f1c..000000000000
--- a/arch/s390/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-/*
- *  S390 version
- *
- *  Derived from "include/asm-i386/siginfo.h"
- */
-
-#ifndef _S390_SIGINFO_H
-#define _S390_SIGINFO_H
-
-#ifdef __s390x__
-#define __ARCH_SI_PREAMBLE_SIZE (4 * sizeof(int))
-#endif
-
-#include <asm-generic/siginfo.h>
-
-#endif
diff --git a/arch/sparc/include/uapi/asm/siginfo.h b/arch/sparc/include/uapi/asm/siginfo.h
index 6c820ea0813b..68bdde4c2a2e 100644
--- a/arch/sparc/include/uapi/asm/siginfo.h
+++ b/arch/sparc/include/uapi/asm/siginfo.h
@@ -4,7 +4,6 @@
 
 #if defined(__sparc__) && defined(__arch64__)
 
-#define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
 #define __ARCH_SI_BAND_T int
 
 #endif /* defined(__sparc__) && defined(__arch64__) */
diff --git a/arch/x86/include/uapi/asm/siginfo.h b/arch/x86/include/uapi/asm/siginfo.h
index b3d157957177..6642d8be40c4 100644
--- a/arch/x86/include/uapi/asm/siginfo.h
+++ b/arch/x86/include/uapi/asm/siginfo.h
@@ -7,8 +7,6 @@
 typedef long long __kernel_si_clock_t __attribute__((aligned(4)));
 #  define __ARCH_SI_CLOCK_T		__kernel_si_clock_t
 #  define __ARCH_SI_ATTRIBUTES		__attribute__((aligned(8)))
-# else /* x86-64 */
-#  define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
 # endif
 #endif
 
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 1811b8101937..cb3d6c267181 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -10,18 +10,7 @@ typedef union sigval {
 	void __user *sival_ptr;
 } sigval_t;
 
-/*
- * This is the size (including padding) of the part of the
- * struct siginfo that is before the union.
- */
-#ifndef __ARCH_SI_PREAMBLE_SIZE
-#define __ARCH_SI_PREAMBLE_SIZE	(3 * sizeof(int))
-#endif
-
 #define SI_MAX_SIZE	128
-#ifndef SI_PAD_SIZE
-#define SI_PAD_SIZE	((SI_MAX_SIZE - __ARCH_SI_PREAMBLE_SIZE) / sizeof(int))
-#endif
 
 /*
  * The default "si_band" type is "long", as specified by POSIX.
@@ -40,96 +29,108 @@ typedef union sigval {
 #define __ARCH_SI_ATTRIBUTES
 #endif
 
-typedef struct siginfo {
-	int si_signo;
-#ifndef __ARCH_HAS_SWAPPED_SIGINFO
-	int si_errno;
-	int si_code;
-#else
-	int si_code;
-	int si_errno;
-#endif
-
-	union {
-		int _pad[SI_PAD_SIZE];
-
-		/* kill() */
-		struct {
-			__kernel_pid_t _pid;	/* sender's pid */
-			__kernel_uid32_t _uid;	/* sender's uid */
-		} _kill;
-
-		/* POSIX.1b timers */
-		struct {
-			__kernel_timer_t _tid;	/* timer id */
-			int _overrun;		/* overrun count */
-			sigval_t _sigval;	/* same as below */
-			int _sys_private;       /* not to be passed to user */
-		} _timer;
-
-		/* POSIX.1b signals */
-		struct {
-			__kernel_pid_t _pid;	/* sender's pid */
-			__kernel_uid32_t _uid;	/* sender's uid */
-			sigval_t _sigval;
-		} _rt;
-
-		/* SIGCHLD */
-		struct {
-			__kernel_pid_t _pid;	/* which child */
-			__kernel_uid32_t _uid;	/* sender's uid */
-			int _status;		/* exit code */
-			__ARCH_SI_CLOCK_T _utime;
-			__ARCH_SI_CLOCK_T _stime;
-		} _sigchld;
-
-		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */
-		struct {
-			void __user *_addr; /* faulting insn/memory ref. */
+union __sifields {
+	/* kill() */
+	struct {
+		__kernel_pid_t _pid;	/* sender's pid */
+		__kernel_uid32_t _uid;	/* sender's uid */
+	} _kill;
+
+	/* POSIX.1b timers */
+	struct {
+		__kernel_timer_t _tid;	/* timer id */
+		int _overrun;		/* overrun count */
+		sigval_t _sigval;	/* same as below */
+		int _sys_private;       /* not to be passed to user */
+	} _timer;
+
+	/* POSIX.1b signals */
+	struct {
+		__kernel_pid_t _pid;	/* sender's pid */
+		__kernel_uid32_t _uid;	/* sender's uid */
+		sigval_t _sigval;
+	} _rt;
+
+	/* SIGCHLD */
+	struct {
+		__kernel_pid_t _pid;	/* which child */
+		__kernel_uid32_t _uid;	/* sender's uid */
+		int _status;		/* exit code */
+		__ARCH_SI_CLOCK_T _utime;
+		__ARCH_SI_CLOCK_T _stime;
+	} _sigchld;
+
+	/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */
+	struct {
+		void __user *_addr; /* faulting insn/memory ref. */
 #ifdef __ARCH_SI_TRAPNO
-			int _trapno;	/* TRAP # which caused the signal */
+		int _trapno;	/* TRAP # which caused the signal */
 #endif
 #ifdef __ia64__
-			int _imm;		/* immediate value for "break" */
-			unsigned int _flags;	/* see ia64 si_flags */
-			unsigned long _isr;	/* isr */
+		int _imm;		/* immediate value for "break" */
+		unsigned int _flags;	/* see ia64 si_flags */
+		unsigned long _isr;	/* isr */
 #endif
 
 #define __ADDR_BND_PKEY_PAD  (__alignof__(void *) < sizeof(short) ? \
 			      sizeof(short) : __alignof__(void *))
-			union {
-				/*
-				 * used when si_code=BUS_MCEERR_AR or
-				 * used when si_code=BUS_MCEERR_AO
-				 */
-				short _addr_lsb; /* LSB of the reported address */
-				/* used when si_code=SEGV_BNDERR */
-				struct {
-					char _dummy_bnd[__ADDR_BND_PKEY_PAD];
-					void __user *_lower;
-					void __user *_upper;
-				} _addr_bnd;
-				/* used when si_code=SEGV_PKUERR */
-				struct {
-					char _dummy_pkey[__ADDR_BND_PKEY_PAD];
-					__u32 _pkey;
-				} _addr_pkey;
-			};
-		} _sigfault;
-
-		/* SIGPOLL */
-		struct {
-			__ARCH_SI_BAND_T _band;	/* POLL_IN, POLL_OUT, POLL_MSG */
-			int _fd;
-		} _sigpoll;
+		union {
+			/*
+			 * used when si_code=BUS_MCEERR_AR or
+			 * used when si_code=BUS_MCEERR_AO
+			 */
+			short _addr_lsb; /* LSB of the reported address */
+			/* used when si_code=SEGV_BNDERR */
+			struct {
+				char _dummy_bnd[__ADDR_BND_PKEY_PAD];
+				void __user *_lower;
+				void __user *_upper;
+			} _addr_bnd;
+			/* used when si_code=SEGV_PKUERR */
+			struct {
+				char _dummy_pkey[__ADDR_BND_PKEY_PAD];
+				__u32 _pkey;
+			} _addr_pkey;
+		};
+	} _sigfault;
+
+	/* SIGPOLL */
+	struct {
+		__ARCH_SI_BAND_T _band;	/* POLL_IN, POLL_OUT, POLL_MSG */
+		int _fd;
+	} _sigpoll;
+
+	/* SIGSYS */
+	struct {
+		void __user *_call_addr; /* calling user insn */
+		int _syscall;	/* triggering system call number */
+		unsigned int _arch;	/* AUDIT_ARCH_* of syscall */
+	} _sigsys;
+};
 
-		/* SIGSYS */
-		struct {
-			void __user *_call_addr; /* calling user insn */
-			int _syscall;	/* triggering system call number */
-			unsigned int _arch;	/* AUDIT_ARCH_* of syscall */
-		} _sigsys;
-	} _sifields;
+#ifndef __ARCH_HAS_SWAPPED_SIGINFO
+#define __SIGINFO 			\
+struct {				\
+	int si_signo;			\
+	int si_errno;			\
+	int si_code;			\
+	union __sifields _sifields;	\
+}
+#else
+#define __SIGINFO 			\
+struct {				\
+	int si_signo;			\
+	int si_code;			\
+	int si_errno;			\
+	union __sifields _sifields;	\
+}
+#endif /* __ARCH_HAS_SWAPPED_SIGINFO */
+
+typedef struct siginfo {
+	union {
+		__SIGINFO;
+		int _si_pad[SI_MAX_SIZE/sizeof(int)];
+	};
 } __ARCH_SI_ATTRIBUTES siginfo_t;
 
 /*
diff --git a/kernel/signal.c b/kernel/signal.c
index e445b0a63faa..debb485a76db 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3963,9 +3963,6 @@ __weak const char *arch_vma_name(struct vm_area_struct *vma)
 
 void __init signals_init(void)
 {
-	/* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */
-	BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE
-		!= offsetof(struct siginfo, _sifields._pad));
 	BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
 
 	sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 3/6] signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE
  2018-09-25 17:19 ` [REVIEW][PATCH 3/6] signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE Eric W. Biederman
@ 2018-09-25 17:19   ` Eric W. Biederman
  0 siblings, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

Rework the defintion of struct siginfo so that the array padding
struct siginfo to SI_MAX_SIZE can be placed in a union along side of
the rest of the struct siginfo members.  The result is that we no
longer need the __ARCH_SI_PREAMBLE_SIZE or SI_PAD_SIZE definitions.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/alpha/include/uapi/asm/siginfo.h   |   1 -
 arch/arm64/include/uapi/asm/Kbuild      |   1 +
 arch/arm64/include/uapi/asm/siginfo.h   |  24 ---
 arch/ia64/include/uapi/asm/siginfo.h    |   2 -
 arch/mips/include/uapi/asm/siginfo.h    |  11 --
 arch/parisc/include/uapi/asm/Kbuild     |   1 +
 arch/parisc/include/uapi/asm/siginfo.h  |  11 --
 arch/powerpc/include/uapi/asm/Kbuild    |   1 +
 arch/powerpc/include/uapi/asm/siginfo.h |  18 ---
 arch/riscv/include/uapi/asm/Kbuild      |   1 +
 arch/riscv/include/uapi/asm/siginfo.h   |  24 ---
 arch/s390/include/uapi/asm/Kbuild       |   1 +
 arch/s390/include/uapi/asm/siginfo.h    |  17 ---
 arch/sparc/include/uapi/asm/siginfo.h   |   1 -
 arch/x86/include/uapi/asm/siginfo.h     |   2 -
 include/uapi/asm-generic/siginfo.h      | 187 ++++++++++++------------
 kernel/signal.c                         |   3 -
 17 files changed, 99 insertions(+), 207 deletions(-)
 delete mode 100644 arch/arm64/include/uapi/asm/siginfo.h
 delete mode 100644 arch/parisc/include/uapi/asm/siginfo.h
 delete mode 100644 arch/powerpc/include/uapi/asm/siginfo.h
 delete mode 100644 arch/riscv/include/uapi/asm/siginfo.h
 delete mode 100644 arch/s390/include/uapi/asm/siginfo.h

diff --git a/arch/alpha/include/uapi/asm/siginfo.h b/arch/alpha/include/uapi/asm/siginfo.h
index db3f0138536f..6e1a2af2f962 100644
--- a/arch/alpha/include/uapi/asm/siginfo.h
+++ b/arch/alpha/include/uapi/asm/siginfo.h
@@ -2,7 +2,6 @@
 #ifndef _ALPHA_SIGINFO_H
 #define _ALPHA_SIGINFO_H
 
-#define __ARCH_SI_PREAMBLE_SIZE		(4 * sizeof(int))
 #define __ARCH_SI_TRAPNO
 
 #include <asm-generic/siginfo.h>
diff --git a/arch/arm64/include/uapi/asm/Kbuild b/arch/arm64/include/uapi/asm/Kbuild
index 198afbf0688f..6c5adf458690 100644
--- a/arch/arm64/include/uapi/asm/Kbuild
+++ b/arch/arm64/include/uapi/asm/Kbuild
@@ -19,3 +19,4 @@ generic-y += swab.h
 generic-y += termbits.h
 generic-y += termios.h
 generic-y += types.h
+generic-y += siginfo.h
diff --git a/arch/arm64/include/uapi/asm/siginfo.h b/arch/arm64/include/uapi/asm/siginfo.h
deleted file mode 100644
index 574d12f86039..000000000000
--- a/arch/arm64/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-/*
- * Copyright (C) 2012 ARM Ltd.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_SIGINFO_H
-#define __ASM_SIGINFO_H
-
-#define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
-
-#include <asm-generic/siginfo.h>
-
-#endif
diff --git a/arch/ia64/include/uapi/asm/siginfo.h b/arch/ia64/include/uapi/asm/siginfo.h
index 52b5af424511..796af1ccaa7e 100644
--- a/arch/ia64/include/uapi/asm/siginfo.h
+++ b/arch/ia64/include/uapi/asm/siginfo.h
@@ -9,8 +9,6 @@
 #define _UAPI_ASM_IA64_SIGINFO_H
 
 
-#define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
-
 #include <asm-generic/siginfo.h>
 
 #define si_imm		_sifields._sigfault._imm	/* as per UNIX SysV ABI spec */
diff --git a/arch/mips/include/uapi/asm/siginfo.h b/arch/mips/include/uapi/asm/siginfo.h
index 262504bd59a5..c34c7eef0a1c 100644
--- a/arch/mips/include/uapi/asm/siginfo.h
+++ b/arch/mips/include/uapi/asm/siginfo.h
@@ -14,17 +14,6 @@
 #define __ARCH_SIGEV_PREAMBLE_SIZE (sizeof(long) + 2*sizeof(int))
 #undef __ARCH_SI_TRAPNO /* exception code needs to fill this ...  */
 
-/*
- * Careful to keep union _sifields from shifting ...
- */
-#if _MIPS_SZLONG == 32
-#define __ARCH_SI_PREAMBLE_SIZE (3 * sizeof(int))
-#elif _MIPS_SZLONG == 64
-#define __ARCH_SI_PREAMBLE_SIZE (4 * sizeof(int))
-#else
-#error _MIPS_SZLONG neither 32 nor 64
-#endif
-
 #define __ARCH_HAS_SWAPPED_SIGINFO
 
 #include <asm-generic/siginfo.h>
diff --git a/arch/parisc/include/uapi/asm/Kbuild b/arch/parisc/include/uapi/asm/Kbuild
index 286ef5a5904b..adb5c64831c7 100644
--- a/arch/parisc/include/uapi/asm/Kbuild
+++ b/arch/parisc/include/uapi/asm/Kbuild
@@ -7,3 +7,4 @@ generic-y += kvm_para.h
 generic-y += param.h
 generic-y += poll.h
 generic-y += resource.h
+generic-y += siginfo.h
diff --git a/arch/parisc/include/uapi/asm/siginfo.h b/arch/parisc/include/uapi/asm/siginfo.h
deleted file mode 100644
index 4a1062e05aaf..000000000000
--- a/arch/parisc/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,11 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-#ifndef _PARISC_SIGINFO_H
-#define _PARISC_SIGINFO_H
-
-#if defined(__LP64__)
-#define __ARCH_SI_PREAMBLE_SIZE   (4 * sizeof(int))
-#endif
-
-#include <asm-generic/siginfo.h>
-
-#endif
diff --git a/arch/powerpc/include/uapi/asm/Kbuild b/arch/powerpc/include/uapi/asm/Kbuild
index 1a6ed5919ffd..a658091a19f9 100644
--- a/arch/powerpc/include/uapi/asm/Kbuild
+++ b/arch/powerpc/include/uapi/asm/Kbuild
@@ -7,3 +7,4 @@ generic-y += poll.h
 generic-y += resource.h
 generic-y += sockios.h
 generic-y += statfs.h
+generic-y += siginfo.h
diff --git a/arch/powerpc/include/uapi/asm/siginfo.h b/arch/powerpc/include/uapi/asm/siginfo.h
deleted file mode 100644
index 1d51d9b88221..000000000000
--- a/arch/powerpc/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
-#ifndef _ASM_POWERPC_SIGINFO_H
-#define _ASM_POWERPC_SIGINFO_H
-
-/*
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-
-#ifdef __powerpc64__
-#    define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
-#endif
-
-#include <asm-generic/siginfo.h>
-
-#endif	/* _ASM_POWERPC_SIGINFO_H */
diff --git a/arch/riscv/include/uapi/asm/Kbuild b/arch/riscv/include/uapi/asm/Kbuild
index 7e91f4850475..5511b9918131 100644
--- a/arch/riscv/include/uapi/asm/Kbuild
+++ b/arch/riscv/include/uapi/asm/Kbuild
@@ -26,3 +26,4 @@ generic-y += swab.h
 generic-y += termbits.h
 generic-y += termios.h
 generic-y += types.h
+generic-y += siginfo.h
diff --git a/arch/riscv/include/uapi/asm/siginfo.h b/arch/riscv/include/uapi/asm/siginfo.h
deleted file mode 100644
index f96849aac662..000000000000
--- a/arch/riscv/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,24 +0,0 @@
-/*
- * Copyright (C) 2012 ARM Ltd.
- * Copyright (C) 2016 SiFive, Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-#ifndef __ASM_SIGINFO_H
-#define __ASM_SIGINFO_H
-
-#define __ARCH_SI_PREAMBLE_SIZE	(__SIZEOF_POINTER__ == 4 ? 12 : 16)
-
-#include <asm-generic/siginfo.h>
-
-#endif
diff --git a/arch/s390/include/uapi/asm/Kbuild b/arch/s390/include/uapi/asm/Kbuild
index e364873e0d10..dc38a90cf091 100644
--- a/arch/s390/include/uapi/asm/Kbuild
+++ b/arch/s390/include/uapi/asm/Kbuild
@@ -18,3 +18,4 @@ generic-y += shmbuf.h
 generic-y += sockios.h
 generic-y += swab.h
 generic-y += termbits.h
+generic-y += siginfo.h
\ No newline at end of file
diff --git a/arch/s390/include/uapi/asm/siginfo.h b/arch/s390/include/uapi/asm/siginfo.h
deleted file mode 100644
index 6984820f2f1c..000000000000
--- a/arch/s390/include/uapi/asm/siginfo.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
-/*
- *  S390 version
- *
- *  Derived from "include/asm-i386/siginfo.h"
- */
-
-#ifndef _S390_SIGINFO_H
-#define _S390_SIGINFO_H
-
-#ifdef __s390x__
-#define __ARCH_SI_PREAMBLE_SIZE (4 * sizeof(int))
-#endif
-
-#include <asm-generic/siginfo.h>
-
-#endif
diff --git a/arch/sparc/include/uapi/asm/siginfo.h b/arch/sparc/include/uapi/asm/siginfo.h
index 6c820ea0813b..68bdde4c2a2e 100644
--- a/arch/sparc/include/uapi/asm/siginfo.h
+++ b/arch/sparc/include/uapi/asm/siginfo.h
@@ -4,7 +4,6 @@
 
 #if defined(__sparc__) && defined(__arch64__)
 
-#define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
 #define __ARCH_SI_BAND_T int
 
 #endif /* defined(__sparc__) && defined(__arch64__) */
diff --git a/arch/x86/include/uapi/asm/siginfo.h b/arch/x86/include/uapi/asm/siginfo.h
index b3d157957177..6642d8be40c4 100644
--- a/arch/x86/include/uapi/asm/siginfo.h
+++ b/arch/x86/include/uapi/asm/siginfo.h
@@ -7,8 +7,6 @@
 typedef long long __kernel_si_clock_t __attribute__((aligned(4)));
 #  define __ARCH_SI_CLOCK_T		__kernel_si_clock_t
 #  define __ARCH_SI_ATTRIBUTES		__attribute__((aligned(8)))
-# else /* x86-64 */
-#  define __ARCH_SI_PREAMBLE_SIZE	(4 * sizeof(int))
 # endif
 #endif
 
diff --git a/include/uapi/asm-generic/siginfo.h b/include/uapi/asm-generic/siginfo.h
index 1811b8101937..cb3d6c267181 100644
--- a/include/uapi/asm-generic/siginfo.h
+++ b/include/uapi/asm-generic/siginfo.h
@@ -10,18 +10,7 @@ typedef union sigval {
 	void __user *sival_ptr;
 } sigval_t;
 
-/*
- * This is the size (including padding) of the part of the
- * struct siginfo that is before the union.
- */
-#ifndef __ARCH_SI_PREAMBLE_SIZE
-#define __ARCH_SI_PREAMBLE_SIZE	(3 * sizeof(int))
-#endif
-
 #define SI_MAX_SIZE	128
-#ifndef SI_PAD_SIZE
-#define SI_PAD_SIZE	((SI_MAX_SIZE - __ARCH_SI_PREAMBLE_SIZE) / sizeof(int))
-#endif
 
 /*
  * The default "si_band" type is "long", as specified by POSIX.
@@ -40,96 +29,108 @@ typedef union sigval {
 #define __ARCH_SI_ATTRIBUTES
 #endif
 
-typedef struct siginfo {
-	int si_signo;
-#ifndef __ARCH_HAS_SWAPPED_SIGINFO
-	int si_errno;
-	int si_code;
-#else
-	int si_code;
-	int si_errno;
-#endif
-
-	union {
-		int _pad[SI_PAD_SIZE];
-
-		/* kill() */
-		struct {
-			__kernel_pid_t _pid;	/* sender's pid */
-			__kernel_uid32_t _uid;	/* sender's uid */
-		} _kill;
-
-		/* POSIX.1b timers */
-		struct {
-			__kernel_timer_t _tid;	/* timer id */
-			int _overrun;		/* overrun count */
-			sigval_t _sigval;	/* same as below */
-			int _sys_private;       /* not to be passed to user */
-		} _timer;
-
-		/* POSIX.1b signals */
-		struct {
-			__kernel_pid_t _pid;	/* sender's pid */
-			__kernel_uid32_t _uid;	/* sender's uid */
-			sigval_t _sigval;
-		} _rt;
-
-		/* SIGCHLD */
-		struct {
-			__kernel_pid_t _pid;	/* which child */
-			__kernel_uid32_t _uid;	/* sender's uid */
-			int _status;		/* exit code */
-			__ARCH_SI_CLOCK_T _utime;
-			__ARCH_SI_CLOCK_T _stime;
-		} _sigchld;
-
-		/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */
-		struct {
-			void __user *_addr; /* faulting insn/memory ref. */
+union __sifields {
+	/* kill() */
+	struct {
+		__kernel_pid_t _pid;	/* sender's pid */
+		__kernel_uid32_t _uid;	/* sender's uid */
+	} _kill;
+
+	/* POSIX.1b timers */
+	struct {
+		__kernel_timer_t _tid;	/* timer id */
+		int _overrun;		/* overrun count */
+		sigval_t _sigval;	/* same as below */
+		int _sys_private;       /* not to be passed to user */
+	} _timer;
+
+	/* POSIX.1b signals */
+	struct {
+		__kernel_pid_t _pid;	/* sender's pid */
+		__kernel_uid32_t _uid;	/* sender's uid */
+		sigval_t _sigval;
+	} _rt;
+
+	/* SIGCHLD */
+	struct {
+		__kernel_pid_t _pid;	/* which child */
+		__kernel_uid32_t _uid;	/* sender's uid */
+		int _status;		/* exit code */
+		__ARCH_SI_CLOCK_T _utime;
+		__ARCH_SI_CLOCK_T _stime;
+	} _sigchld;
+
+	/* SIGILL, SIGFPE, SIGSEGV, SIGBUS, SIGTRAP, SIGEMT */
+	struct {
+		void __user *_addr; /* faulting insn/memory ref. */
 #ifdef __ARCH_SI_TRAPNO
-			int _trapno;	/* TRAP # which caused the signal */
+		int _trapno;	/* TRAP # which caused the signal */
 #endif
 #ifdef __ia64__
-			int _imm;		/* immediate value for "break" */
-			unsigned int _flags;	/* see ia64 si_flags */
-			unsigned long _isr;	/* isr */
+		int _imm;		/* immediate value for "break" */
+		unsigned int _flags;	/* see ia64 si_flags */
+		unsigned long _isr;	/* isr */
 #endif
 
 #define __ADDR_BND_PKEY_PAD  (__alignof__(void *) < sizeof(short) ? \
 			      sizeof(short) : __alignof__(void *))
-			union {
-				/*
-				 * used when si_code=BUS_MCEERR_AR or
-				 * used when si_code=BUS_MCEERR_AO
-				 */
-				short _addr_lsb; /* LSB of the reported address */
-				/* used when si_code=SEGV_BNDERR */
-				struct {
-					char _dummy_bnd[__ADDR_BND_PKEY_PAD];
-					void __user *_lower;
-					void __user *_upper;
-				} _addr_bnd;
-				/* used when si_code=SEGV_PKUERR */
-				struct {
-					char _dummy_pkey[__ADDR_BND_PKEY_PAD];
-					__u32 _pkey;
-				} _addr_pkey;
-			};
-		} _sigfault;
-
-		/* SIGPOLL */
-		struct {
-			__ARCH_SI_BAND_T _band;	/* POLL_IN, POLL_OUT, POLL_MSG */
-			int _fd;
-		} _sigpoll;
+		union {
+			/*
+			 * used when si_code=BUS_MCEERR_AR or
+			 * used when si_code=BUS_MCEERR_AO
+			 */
+			short _addr_lsb; /* LSB of the reported address */
+			/* used when si_code=SEGV_BNDERR */
+			struct {
+				char _dummy_bnd[__ADDR_BND_PKEY_PAD];
+				void __user *_lower;
+				void __user *_upper;
+			} _addr_bnd;
+			/* used when si_code=SEGV_PKUERR */
+			struct {
+				char _dummy_pkey[__ADDR_BND_PKEY_PAD];
+				__u32 _pkey;
+			} _addr_pkey;
+		};
+	} _sigfault;
+
+	/* SIGPOLL */
+	struct {
+		__ARCH_SI_BAND_T _band;	/* POLL_IN, POLL_OUT, POLL_MSG */
+		int _fd;
+	} _sigpoll;
+
+	/* SIGSYS */
+	struct {
+		void __user *_call_addr; /* calling user insn */
+		int _syscall;	/* triggering system call number */
+		unsigned int _arch;	/* AUDIT_ARCH_* of syscall */
+	} _sigsys;
+};
 
-		/* SIGSYS */
-		struct {
-			void __user *_call_addr; /* calling user insn */
-			int _syscall;	/* triggering system call number */
-			unsigned int _arch;	/* AUDIT_ARCH_* of syscall */
-		} _sigsys;
-	} _sifields;
+#ifndef __ARCH_HAS_SWAPPED_SIGINFO
+#define __SIGINFO 			\
+struct {				\
+	int si_signo;			\
+	int si_errno;			\
+	int si_code;			\
+	union __sifields _sifields;	\
+}
+#else
+#define __SIGINFO 			\
+struct {				\
+	int si_signo;			\
+	int si_code;			\
+	int si_errno;			\
+	union __sifields _sifields;	\
+}
+#endif /* __ARCH_HAS_SWAPPED_SIGINFO */
+
+typedef struct siginfo {
+	union {
+		__SIGINFO;
+		int _si_pad[SI_MAX_SIZE/sizeof(int)];
+	};
 } __ARCH_SI_ATTRIBUTES siginfo_t;
 
 /*
diff --git a/kernel/signal.c b/kernel/signal.c
index e445b0a63faa..debb485a76db 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3963,9 +3963,6 @@ __weak const char *arch_vma_name(struct vm_area_struct *vma)
 
 void __init signals_init(void)
 {
-	/* If this check fails, the __ARCH_SI_PREAMBLE_SIZE value is wrong! */
-	BUILD_BUG_ON(__ARCH_SI_PREAMBLE_SIZE
-		!= offsetof(struct siginfo, _sifields._pad));
 	BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
 
 	sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 4/6] signal: Introduce copy_siginfo_from_user and use it's return value
  2018-09-25 17:16 [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure Eric W. Biederman
                   ` (3 preceding siblings ...)
  2018-09-25 17:19 ` [REVIEW][PATCH 3/6] signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE Eric W. Biederman
@ 2018-09-25 17:19 ` Eric W. Biederman
  2018-09-25 17:19   ` Eric W. Biederman
  2018-09-25 17:19 ` [REVIEW][PATCH 5/6] signal: Distinguish between kernel_siginfo and siginfo Eric W. Biederman
  2018-09-25 17:19 ` [REVIEW][PATCH 6/6] signal: Use a smaller struct siginfo in the kernel Eric W. Biederman
  6 siblings, 1 reply; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

In preparation for using a smaller version of siginfo in the kernel
introduce copy_siginfo_from_user and use it when siginfo is copied from
userspace.

Make the pattern for using copy_siginfo_from_user and
copy_siginfo_from_user32 to capture the return value and return that
value on error.

This is a necessary prerequisite for using a smaller siginfo
in the kernel than the kernel exports to userspace.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 include/linux/signal.h |  1 +
 kernel/ptrace.c        | 12 +++++-------
 kernel/signal.c        | 25 ++++++++++++++++---------
 3 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/include/linux/signal.h b/include/linux/signal.h
index 3d4cd5db30a9..de94c159bfb0 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -22,6 +22,7 @@ static inline void clear_siginfo(struct siginfo *info)
 }
 
 int copy_siginfo_to_user(struct siginfo __user *to, const struct siginfo *from);
+int copy_siginfo_from_user(struct siginfo *to, const struct siginfo __user *from);
 
 enum siginfo_layout {
 	SIL_KILL,
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 45f77a1b9c97..a807ff5cc1a9 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -919,9 +919,8 @@ int ptrace_request(struct task_struct *child, long request,
 		break;
 
 	case PTRACE_SETSIGINFO:
-		if (copy_from_user(&siginfo, datavp, sizeof siginfo))
-			ret = -EFAULT;
-		else
+		ret = copy_siginfo_from_user(&siginfo, datavp);
+		if (!ret)
 			ret = ptrace_setsiginfo(child, &siginfo);
 		break;
 
@@ -1215,10 +1214,9 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request,
 		break;
 
 	case PTRACE_SETSIGINFO:
-		if (copy_siginfo_from_user32(
-			    &siginfo, (struct compat_siginfo __user *) datap))
-			ret = -EFAULT;
-		else
+		ret = copy_siginfo_from_user32(
+			&siginfo, (struct compat_siginfo __user *) datap);
+		if (!ret)
 			ret = ptrace_setsiginfo(child, &siginfo);
 		break;
 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
diff --git a/kernel/signal.c b/kernel/signal.c
index debb485a76db..c0e289e62d77 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2896,6 +2896,13 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
 	return 0;
 }
 
+int copy_siginfo_from_user(siginfo_t *to, const siginfo_t __user *from)
+{
+	if (copy_from_user(to, from, sizeof(struct siginfo)))
+		return -EFAULT;
+	return 0;
+}
+
 #ifdef CONFIG_COMPAT
 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
 			   const struct siginfo *from)
@@ -3323,8 +3330,9 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
 	siginfo_t info;
-	if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
-		return -EFAULT;
+	int ret = copy_siginfo_from_user(&info, uinfo);
+	if (unlikely(ret))
+		return ret;
 	return do_rt_sigqueueinfo(pid, sig, &info);
 }
 
@@ -3365,10 +3373,9 @@ SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
 	siginfo_t info;
-
-	if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
-		return -EFAULT;
-
+	int ret = copy_siginfo_from_user(&info, uinfo);
+	if (unlikely(ret))
+		return ret;
 	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
 }
 
@@ -3380,9 +3387,9 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
 			struct compat_siginfo __user *, uinfo)
 {
 	siginfo_t info;
-
-	if (copy_siginfo_from_user32(&info, uinfo))
-		return -EFAULT;
+	int ret = copy_siginfo_from_user32(&info, uinfo);
+	if (unlikely(ret))
+		return ret;
 	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
 }
 #endif
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 4/6] signal: Introduce copy_siginfo_from_user and use it's return value
  2018-09-25 17:19 ` [REVIEW][PATCH 4/6] signal: Introduce copy_siginfo_from_user and use it's return value Eric W. Biederman
@ 2018-09-25 17:19   ` Eric W. Biederman
  0 siblings, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

In preparation for using a smaller version of siginfo in the kernel
introduce copy_siginfo_from_user and use it when siginfo is copied from
userspace.

Make the pattern for using copy_siginfo_from_user and
copy_siginfo_from_user32 to capture the return value and return that
value on error.

This is a necessary prerequisite for using a smaller siginfo
in the kernel than the kernel exports to userspace.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 include/linux/signal.h |  1 +
 kernel/ptrace.c        | 12 +++++-------
 kernel/signal.c        | 25 ++++++++++++++++---------
 3 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/include/linux/signal.h b/include/linux/signal.h
index 3d4cd5db30a9..de94c159bfb0 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -22,6 +22,7 @@ static inline void clear_siginfo(struct siginfo *info)
 }
 
 int copy_siginfo_to_user(struct siginfo __user *to, const struct siginfo *from);
+int copy_siginfo_from_user(struct siginfo *to, const struct siginfo __user *from);
 
 enum siginfo_layout {
 	SIL_KILL,
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 45f77a1b9c97..a807ff5cc1a9 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -919,9 +919,8 @@ int ptrace_request(struct task_struct *child, long request,
 		break;
 
 	case PTRACE_SETSIGINFO:
-		if (copy_from_user(&siginfo, datavp, sizeof siginfo))
-			ret = -EFAULT;
-		else
+		ret = copy_siginfo_from_user(&siginfo, datavp);
+		if (!ret)
 			ret = ptrace_setsiginfo(child, &siginfo);
 		break;
 
@@ -1215,10 +1214,9 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request,
 		break;
 
 	case PTRACE_SETSIGINFO:
-		if (copy_siginfo_from_user32(
-			    &siginfo, (struct compat_siginfo __user *) datap))
-			ret = -EFAULT;
-		else
+		ret = copy_siginfo_from_user32(
+			&siginfo, (struct compat_siginfo __user *) datap);
+		if (!ret)
 			ret = ptrace_setsiginfo(child, &siginfo);
 		break;
 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
diff --git a/kernel/signal.c b/kernel/signal.c
index debb485a76db..c0e289e62d77 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2896,6 +2896,13 @@ int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
 	return 0;
 }
 
+int copy_siginfo_from_user(siginfo_t *to, const siginfo_t __user *from)
+{
+	if (copy_from_user(to, from, sizeof(struct siginfo)))
+		return -EFAULT;
+	return 0;
+}
+
 #ifdef CONFIG_COMPAT
 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
 			   const struct siginfo *from)
@@ -3323,8 +3330,9 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
 	siginfo_t info;
-	if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
-		return -EFAULT;
+	int ret = copy_siginfo_from_user(&info, uinfo);
+	if (unlikely(ret))
+		return ret;
 	return do_rt_sigqueueinfo(pid, sig, &info);
 }
 
@@ -3365,10 +3373,9 @@ SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
 	siginfo_t info;
-
-	if (copy_from_user(&info, uinfo, sizeof(siginfo_t)))
-		return -EFAULT;
-
+	int ret = copy_siginfo_from_user(&info, uinfo);
+	if (unlikely(ret))
+		return ret;
 	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
 }
 
@@ -3380,9 +3387,9 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
 			struct compat_siginfo __user *, uinfo)
 {
 	siginfo_t info;
-
-	if (copy_siginfo_from_user32(&info, uinfo))
-		return -EFAULT;
+	int ret = copy_siginfo_from_user32(&info, uinfo);
+	if (unlikely(ret))
+		return ret;
 	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
 }
 #endif
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 5/6] signal: Distinguish between kernel_siginfo and siginfo
  2018-09-25 17:16 [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure Eric W. Biederman
                   ` (4 preceding siblings ...)
  2018-09-25 17:19 ` [REVIEW][PATCH 4/6] signal: Introduce copy_siginfo_from_user and use it's return value Eric W. Biederman
@ 2018-09-25 17:19 ` Eric W. Biederman
  2018-09-25 17:19   ` Eric W. Biederman
  2018-09-25 17:19 ` [REVIEW][PATCH 6/6] signal: Use a smaller struct siginfo in the kernel Eric W. Biederman
  6 siblings, 1 reply; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

Linus recently observed that if we did not worry about the padding
member in struct siginfo it is only about 48 bytes, and 48 bytes is
much nicer than 128 bytes for allocating on the stack and copying
around in the kernel.

The obvious thing of only adding the padding when userspace is
including siginfo.h won't work as there are sigframe definitions in
the kernel that embed struct siginfo.

So split siginfo in two; kernel_siginfo and siginfo.  Keeping the
traditional name for the userspace definition.  While the version that
is used internally to the kernel and ultimately will not be padded to
128 bytes is called kernel_siginfo.

The definition of struct kernel_siginfo I have put in include/signal_types.h

A set of buildtime checks has been added to verify the two structures have
the same field offsets.

To make it easy to verify the change kernel_siginfo retains the same
size as siginfo.  The reduction in size comes in a following change.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/x86/include/asm/compat.h |   2 +-
 drivers/usb/core/devio.c      |   4 +-
 fs/binfmt_elf.c               |   6 +-
 fs/coredump.c                 |   2 +-
 fs/fcntl.c                    |   2 +-
 fs/signalfd.c                 |   6 +-
 include/linux/binfmts.h       |   2 +-
 include/linux/compat.h        |   4 +-
 include/linux/coredump.h      |   4 +-
 include/linux/lsm_hooks.h     |   4 +-
 include/linux/posix-timers.h  |   2 +-
 include/linux/ptrace.h        |   2 +-
 include/linux/sched.h         |   2 +-
 include/linux/sched/signal.h  |  18 ++--
 include/linux/security.h      |   6 +-
 include/linux/signal.h        |  15 ++--
 include/linux/signal_types.h  |  11 ++-
 include/trace/events/signal.h |   4 +-
 ipc/mqueue.c                  |   2 +-
 kernel/ptrace.c               |  10 +--
 kernel/seccomp.c              |   6 +-
 kernel/signal.c               | 151 ++++++++++++++++++++++------------
 kernel/time/posix-timers.c    |   2 +-
 security/apparmor/lsm.c       |   2 +-
 security/security.c           |   2 +-
 security/selinux/hooks.c      |   2 +-
 security/smack/smack_lsm.c    |   2 +-
 27 files changed, 165 insertions(+), 110 deletions(-)

diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index fb97cf7c4137..a0f46bdd9f24 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -240,6 +240,6 @@ static inline bool in_compat_syscall(void)
 
 struct compat_siginfo;
 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
-		const siginfo_t *from, bool x32_ABI);
+		const kernel_siginfo_t *from, bool x32_ABI);
 
 #endif /* _ASM_X86_COMPAT_H */
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 6ce77b33da61..c260ea8808b0 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -582,7 +582,7 @@ static void async_completed(struct urb *urb)
 {
 	struct async *as = urb->context;
 	struct usb_dev_state *ps = as->ps;
-	struct siginfo sinfo;
+	struct kernel_siginfo sinfo;
 	struct pid *pid = NULL;
 	const struct cred *cred = NULL;
 	unsigned long flags;
@@ -2599,7 +2599,7 @@ const struct file_operations usbdev_file_operations = {
 static void usbdev_remove(struct usb_device *udev)
 {
 	struct usb_dev_state *ps;
-	struct siginfo sinfo;
+	struct kernel_siginfo sinfo;
 
 	while (!list_empty(&udev->filelist)) {
 		ps = list_entry(udev->filelist.next, struct usb_dev_state, list);
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index efae2fb0930a..54207327f98f 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1580,7 +1580,7 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
 }
 
 static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
-		const siginfo_t *siginfo)
+		const kernel_siginfo_t *siginfo)
 {
 	mm_segment_t old_fs = get_fs();
 	set_fs(KERNEL_DS);
@@ -1782,7 +1782,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 
 static int fill_note_info(struct elfhdr *elf, int phdrs,
 			  struct elf_note_info *info,
-			  const siginfo_t *siginfo, struct pt_regs *regs)
+			  const kernel_siginfo_t *siginfo, struct pt_regs *regs)
 {
 	struct task_struct *dump_task = current;
 	const struct user_regset_view *view = task_user_regset_view(dump_task);
@@ -2031,7 +2031,7 @@ static int elf_note_info_init(struct elf_note_info *info)
 
 static int fill_note_info(struct elfhdr *elf, int phdrs,
 			  struct elf_note_info *info,
-			  const siginfo_t *siginfo, struct pt_regs *regs)
+			  const kernel_siginfo_t *siginfo, struct pt_regs *regs)
 {
 	struct list_head *t;
 	struct core_thread *ct;
diff --git a/fs/coredump.c b/fs/coredump.c
index 1e2c87acac9b..e42e17e55bfd 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -536,7 +536,7 @@ static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
 	return err;
 }
 
-void do_coredump(const siginfo_t *siginfo)
+void do_coredump(const kernel_siginfo_t *siginfo)
 {
 	struct core_state core_state;
 	struct core_name cn;
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 4137d96534a6..083185174c6d 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -735,7 +735,7 @@ static void send_sigio_to_task(struct task_struct *p,
 		return;
 
 	switch (signum) {
-		siginfo_t si;
+		kernel_siginfo_t si;
 		default:
 			/* Queue a rt signal with the appropriate fd as its
 			   value.  We use SI_SIGIO as the source, not 
diff --git a/fs/signalfd.c b/fs/signalfd.c
index 4fcd1498acf5..757afc7c5895 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -79,7 +79,7 @@ static __poll_t signalfd_poll(struct file *file, poll_table *wait)
  * Copied from copy_siginfo_to_user() in kernel/signal.c
  */
 static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
-			     siginfo_t const *kinfo)
+			     kernel_siginfo_t const *kinfo)
 {
 	struct signalfd_siginfo new;
 
@@ -163,7 +163,7 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
 	return sizeof(*uinfo);
 }
 
-static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info,
+static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info,
 				int nonblock)
 {
 	ssize_t ret;
@@ -215,7 +215,7 @@ static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,
 	struct signalfd_siginfo __user *siginfo;
 	int nonblock = file->f_flags & O_NONBLOCK;
 	ssize_t ret, total = 0;
-	siginfo_t info;
+	kernel_siginfo_t info;
 
 	count /= sizeof(struct signalfd_siginfo);
 	if (!count)
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index c05f24fac4f6..e9f5fe69df31 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -78,7 +78,7 @@ struct linux_binprm {
 
 /* Function parameter for binfmt->coredump */
 struct coredump_params {
-	const siginfo_t *siginfo;
+	const kernel_siginfo_t *siginfo;
 	struct pt_regs *regs;
 	struct file *file;
 	unsigned long limit;
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 1a3c4f37e908..4565d65b1776 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -452,8 +452,8 @@ long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
 		       unsigned long bitmap_size);
 long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 		       unsigned long bitmap_size);
-int copy_siginfo_from_user32(siginfo_t *to, const struct compat_siginfo __user *from);
-int copy_siginfo_to_user32(struct compat_siginfo __user *to, const siginfo_t *from);
+int copy_siginfo_from_user32(kernel_siginfo_t *to, const struct compat_siginfo __user *from);
+int copy_siginfo_to_user32(struct compat_siginfo __user *to, const kernel_siginfo_t *from);
 int get_compat_sigevent(struct sigevent *event,
 		const struct compat_sigevent __user *u_event);
 
diff --git a/include/linux/coredump.h b/include/linux/coredump.h
index 207aed96a5b7..abf4b4e65dbb 100644
--- a/include/linux/coredump.h
+++ b/include/linux/coredump.h
@@ -17,9 +17,9 @@ extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr);
 extern int dump_align(struct coredump_params *cprm, int align);
 extern void dump_truncate(struct coredump_params *cprm);
 #ifdef CONFIG_COREDUMP
-extern void do_coredump(const siginfo_t *siginfo);
+extern void do_coredump(const kernel_siginfo_t *siginfo);
 #else
-static inline void do_coredump(const siginfo_t *siginfo) {}
+static inline void do_coredump(const kernel_siginfo_t *siginfo) {}
 #endif
 
 #endif /* _LINUX_COREDUMP_H */
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 97a020c616ad..bb40f6d34163 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -672,7 +672,7 @@
  *	Return 0 if permission is granted.
  * @task_kill:
  *	Check permission before sending signal @sig to @p.  @info can be NULL,
- *	the constant 1, or a pointer to a siginfo structure.  If @info is 1 or
+ *	the constant 1, or a pointer to a kernel_siginfo structure.  If @info is 1 or
  *	SI_FROMKERNEL(info) is true, then the signal should be viewed as coming
  *	from the kernel and should typically be permitted.
  *	SIGIO signals are handled separately by the send_sigiotask hook in
@@ -1606,7 +1606,7 @@ union security_list_options {
 	int (*task_setscheduler)(struct task_struct *p);
 	int (*task_getscheduler)(struct task_struct *p);
 	int (*task_movememory)(struct task_struct *p);
-	int (*task_kill)(struct task_struct *p, struct siginfo *info,
+	int (*task_kill)(struct task_struct *p, struct kernel_siginfo *info,
 				int sig, const struct cred *cred);
 	int (*task_prctl)(int option, unsigned long arg2, unsigned long arg3,
 				unsigned long arg4, unsigned long arg5);
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index ee7e987ea1b4..e96581ca7c9d 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -126,5 +126,5 @@ void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
 
 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
 
-void posixtimer_rearm(struct siginfo *info);
+void posixtimer_rearm(struct kernel_siginfo *info);
 #endif
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 1de2235511c8..d19a795100da 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -341,7 +341,7 @@ extern void user_single_step_report(struct pt_regs *regs);
 #else
 static inline void user_single_step_report(struct pt_regs *regs)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	clear_siginfo(&info);
 	info.si_signo = SIGTRAP;
 	info.si_errno = 0;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 977cb57d7bc9..2ba88082e1ef 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -960,7 +960,7 @@ struct task_struct {
 
 	/* Ptrace state: */
 	unsigned long			ptrace_message;
-	siginfo_t			*last_siginfo;
+	kernel_siginfo_t		*last_siginfo;
 
 	struct task_io_accounting	ioac;
 #ifdef CONFIG_TASK_XACCT
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 9e07f3521549..13789d10a50e 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -270,12 +270,12 @@ static inline int signal_group_exit(const struct signal_struct *sig)
 extern void flush_signals(struct task_struct *);
 extern void ignore_signals(struct task_struct *);
 extern void flush_signal_handlers(struct task_struct *, int force_default);
-extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);
+extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info);
 
 static inline int kernel_dequeue_signal(void)
 {
 	struct task_struct *tsk = current;
-	siginfo_t __info;
+	kernel_siginfo_t __info;
 	int ret;
 
 	spin_lock_irq(&tsk->sighand->siglock);
@@ -322,12 +322,12 @@ int force_sig_pkuerr(void __user *addr, u32 pkey);
 
 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
 
-extern int send_sig_info(int, struct siginfo *, struct task_struct *);
+extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
 extern void force_sigsegv(int sig, struct task_struct *p);
-extern int force_sig_info(int, struct siginfo *, struct task_struct *);
-extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
-extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
-extern int kill_pid_info_as_cred(int, struct siginfo *, struct pid *,
+extern int force_sig_info(int, struct kernel_siginfo *, struct task_struct *);
+extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
+extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
+extern int kill_pid_info_as_cred(int, struct kernel_siginfo *, struct pid *,
 				const struct cred *);
 extern int kill_pgrp(struct pid *pid, int sig, int priv);
 extern int kill_pid(struct pid *pid, int sig, int priv);
@@ -475,8 +475,8 @@ static inline int kill_cad_pid(int sig, int priv)
 }
 
 /* These can be the second arg to send_sig_info/send_group_sig_info.  */
-#define SEND_SIG_NOINFO ((struct siginfo *) 0)
-#define SEND_SIG_PRIV	((struct siginfo *) 1)
+#define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
+#define SEND_SIG_PRIV	((struct kernel_siginfo *) 1)
 
 /*
  * True if we are on the alternate signal stack.
diff --git a/include/linux/security.h b/include/linux/security.h
index 75f4156c84d7..d170a5b031f3 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -35,7 +35,7 @@
 struct linux_binprm;
 struct cred;
 struct rlimit;
-struct siginfo;
+struct kernel_siginfo;
 struct sembuf;
 struct kern_ipc_perm;
 struct audit_context;
@@ -361,7 +361,7 @@ int security_task_setrlimit(struct task_struct *p, unsigned int resource,
 int security_task_setscheduler(struct task_struct *p);
 int security_task_getscheduler(struct task_struct *p);
 int security_task_movememory(struct task_struct *p);
-int security_task_kill(struct task_struct *p, struct siginfo *info,
+int security_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 			int sig, const struct cred *cred);
 int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 			unsigned long arg4, unsigned long arg5);
@@ -1020,7 +1020,7 @@ static inline int security_task_movememory(struct task_struct *p)
 }
 
 static inline int security_task_kill(struct task_struct *p,
-				     struct siginfo *info, int sig,
+				     struct kernel_siginfo *info, int sig,
 				     const struct cred *cred)
 {
 	return 0;
diff --git a/include/linux/signal.h b/include/linux/signal.h
index de94c159bfb0..70031b10b918 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -11,18 +11,19 @@ struct task_struct;
 /* for sysctl */
 extern int print_fatal_signals;
 
-static inline void copy_siginfo(struct siginfo *to, const struct siginfo *from)
+static inline void copy_siginfo(kernel_siginfo_t *to,
+				const kernel_siginfo_t *from)
 {
 	memcpy(to, from, sizeof(*to));
 }
 
-static inline void clear_siginfo(struct siginfo *info)
+static inline void clear_siginfo(kernel_siginfo_t *info)
 {
 	memset(info, 0, sizeof(*info));
 }
 
-int copy_siginfo_to_user(struct siginfo __user *to, const struct siginfo *from);
-int copy_siginfo_from_user(struct siginfo *to, const struct siginfo __user *from);
+int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
+int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
 
 enum siginfo_layout {
 	SIL_KILL,
@@ -258,11 +259,11 @@ struct pt_regs;
 enum pid_type;
 
 extern int next_signal(struct sigpending *pending, sigset_t *mask);
-extern int do_send_sig_info(int sig, struct siginfo *info,
+extern int do_send_sig_info(int sig, struct kernel_siginfo *info,
 				struct task_struct *p, enum pid_type type);
-extern int group_send_sig_info(int sig, struct siginfo *info,
+extern int group_send_sig_info(int sig, struct kernel_siginfo *info,
 			       struct task_struct *p, enum pid_type type);
-extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
+extern int __group_send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
 extern int sigprocmask(int, sigset_t *, sigset_t *);
 extern void set_current_blocked(sigset_t *);
 extern void __set_current_blocked(const sigset_t *);
diff --git a/include/linux/signal_types.h b/include/linux/signal_types.h
index 222ae696000b..2a40a9c5e4ad 100644
--- a/include/linux/signal_types.h
+++ b/include/linux/signal_types.h
@@ -9,6 +9,13 @@
 #include <linux/list.h>
 #include <uapi/linux/signal.h>
 
+typedef struct kernel_siginfo {
+	union {
+		__SIGINFO;
+		int _si_pad[SI_MAX_SIZE/sizeof(int)];
+	};
+} kernel_siginfo_t;
+
 /*
  * Real Time signals may be queued.
  */
@@ -16,7 +23,7 @@
 struct sigqueue {
 	struct list_head list;
 	int flags;
-	siginfo_t info;
+	kernel_siginfo_t info;
 	struct user_struct *user;
 };
 
@@ -60,7 +67,7 @@ struct old_sigaction {
 
 struct ksignal {
 	struct k_sigaction ka;
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int sig;
 };
 
diff --git a/include/trace/events/signal.h b/include/trace/events/signal.h
index 3deeed50ffd0..1db7e4b07c01 100644
--- a/include/trace/events/signal.h
+++ b/include/trace/events/signal.h
@@ -49,7 +49,7 @@ enum {
  */
 TRACE_EVENT(signal_generate,
 
-	TP_PROTO(int sig, struct siginfo *info, struct task_struct *task,
+	TP_PROTO(int sig, struct kernel_siginfo *info, struct task_struct *task,
 			int group, int result),
 
 	TP_ARGS(sig, info, task, group, result),
@@ -95,7 +95,7 @@ TRACE_EVENT(signal_generate,
  */
 TRACE_EVENT(signal_deliver,
 
-	TP_PROTO(int sig, struct siginfo *info, struct k_sigaction *ka),
+	TP_PROTO(int sig, struct kernel_siginfo *info, struct k_sigaction *ka),
 
 	TP_ARGS(sig, info, ka),
 
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index c0d58f390c3b..cc41de3b8deb 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -655,7 +655,7 @@ static void __do_notify(struct mqueue_inode_info *info)
 	 * synchronously. */
 	if (info->notify_owner &&
 	    info->attr.mq_curmsgs == 1) {
-		struct siginfo sig_i;
+		struct kernel_siginfo sig_i;
 		switch (info->notify.sigev_notify) {
 		case SIGEV_NONE:
 			break;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index a807ff5cc1a9..c2cee9db5204 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -651,7 +651,7 @@ static int ptrace_setoptions(struct task_struct *child, unsigned long data)
 	return 0;
 }
 
-static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
+static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
 {
 	unsigned long flags;
 	int error = -ESRCH;
@@ -667,7 +667,7 @@ static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
 	return error;
 }
 
-static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
+static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
 {
 	unsigned long flags;
 	int error = -ESRCH;
@@ -709,7 +709,7 @@ static int ptrace_peek_siginfo(struct task_struct *child,
 		pending = &child->pending;
 
 	for (i = 0; i < arg.nr; ) {
-		siginfo_t info;
+		kernel_siginfo_t info;
 		s32 off = arg.off + i;
 
 		spin_lock_irq(&child->sighand->siglock);
@@ -885,7 +885,7 @@ int ptrace_request(struct task_struct *child, long request,
 {
 	bool seized = child->ptrace & PT_SEIZED;
 	int ret = -EIO;
-	siginfo_t siginfo, *si;
+	kernel_siginfo_t siginfo, *si;
 	void __user *datavp = (void __user *) data;
 	unsigned long __user *datalp = datavp;
 	unsigned long flags;
@@ -1180,7 +1180,7 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request,
 {
 	compat_ulong_t __user *datap = compat_ptr(data);
 	compat_ulong_t word;
-	siginfo_t siginfo;
+	kernel_siginfo_t siginfo;
 	int ret;
 
 	switch (request) {
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index fd023ac24e10..4d7809cdd27d 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -522,7 +522,7 @@ void put_seccomp_filter(struct task_struct *tsk)
 	__put_seccomp_filter(tsk->seccomp.filter);
 }
 
-static void seccomp_init_siginfo(siginfo_t *info, int syscall, int reason)
+static void seccomp_init_siginfo(kernel_siginfo_t *info, int syscall, int reason)
 {
 	clear_siginfo(info);
 	info->si_signo = SIGSYS;
@@ -542,7 +542,7 @@ static void seccomp_init_siginfo(siginfo_t *info, int syscall, int reason)
  */
 static void seccomp_send_sigsys(int syscall, int reason)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 	seccomp_init_siginfo(&info, syscall, reason);
 	force_sig_info(SIGSYS, &info, current);
 }
@@ -747,7 +747,7 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
 		/* Dump core only if this is the last remaining thread. */
 		if (action == SECCOMP_RET_KILL_PROCESS ||
 		    get_nr_threads(current) == 1) {
-			siginfo_t info;
+			kernel_siginfo_t info;
 
 			/* Show the original registers in the dump. */
 			syscall_rollback(current, task_pt_regs(current));
diff --git a/kernel/signal.c b/kernel/signal.c
index c0e289e62d77..161cad4e448c 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -549,7 +549,7 @@ bool unhandled_signal(struct task_struct *tsk, int sig)
 	return !tsk->ptrace;
 }
 
-static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
+static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
 			   bool *resched_timer)
 {
 	struct sigqueue *q, *first = NULL;
@@ -595,7 +595,7 @@ static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
 }
 
 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
-			siginfo_t *info, bool *resched_timer)
+			kernel_siginfo_t *info, bool *resched_timer)
 {
 	int sig = next_signal(pending, mask);
 
@@ -610,7 +610,7 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
  *
  * All callers have to hold the siglock.
  */
-int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
+int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
 {
 	bool resched_timer = false;
 	int signr;
@@ -737,12 +737,12 @@ static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
 	}
 }
 
-static inline int is_si_special(const struct siginfo *info)
+static inline int is_si_special(const struct kernel_siginfo *info)
 {
 	return info <= SEND_SIG_PRIV;
 }
 
-static inline bool si_fromuser(const struct siginfo *info)
+static inline bool si_fromuser(const struct kernel_siginfo *info)
 {
 	return info == SEND_SIG_NOINFO ||
 		(!is_si_special(info) && SI_FROMUSER(info));
@@ -767,7 +767,7 @@ static bool kill_ok_by_cred(struct task_struct *t)
  * Bad permissions for sending the signal
  * - the caller must hold the RCU read lock
  */
-static int check_kill_permission(int sig, struct siginfo *info,
+static int check_kill_permission(int sig, struct kernel_siginfo *info,
 				 struct task_struct *t)
 {
 	struct pid *sid;
@@ -1010,7 +1010,7 @@ static inline bool legacy_queue(struct sigpending *signals, int sig)
 }
 
 #ifdef CONFIG_USER_NS
-static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t)
 {
 	if (current_user_ns() == task_cred_xxx(t, user_ns))
 		return;
@@ -1024,13 +1024,13 @@ static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_str
 	rcu_read_unlock();
 }
 #else
-static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t)
 {
 	return;
 }
 #endif
 
-static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
+static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
 			enum pid_type type, int from_ancestor_ns)
 {
 	struct sigpending *pending;
@@ -1150,7 +1150,7 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
 	return ret;
 }
 
-static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
+static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
 			enum pid_type type)
 {
 	int from_ancestor_ns = 0;
@@ -1197,12 +1197,12 @@ static int __init setup_print_fatal_signals(char *str)
 __setup("print-fatal-signals=", setup_print_fatal_signals);
 
 int
-__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+__group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
 {
 	return send_signal(sig, info, p, PIDTYPE_TGID);
 }
 
-int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
+int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
 			enum pid_type type)
 {
 	unsigned long flags;
@@ -1228,7 +1228,7 @@ int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
  * that is why we also clear SIGNAL_UNKILLABLE.
  */
 int
-force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+force_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *t)
 {
 	unsigned long int flags;
 	int ret, blocked, ignored;
@@ -1316,8 +1316,8 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
 /*
  * send signal info to all the members of a group
  */
-int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
-			enum pid_type type)
+int group_send_sig_info(int sig, struct kernel_siginfo *info,
+			struct task_struct *p, enum pid_type type)
 {
 	int ret;
 
@@ -1336,7 +1336,7 @@ int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
  * control characters do (^C, ^Z etc)
  * - the caller must hold at least a readlock on tasklist_lock
  */
-int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
+int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
 {
 	struct task_struct *p = NULL;
 	int retval, success;
@@ -1351,7 +1351,7 @@ int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
 	return success ? 0 : retval;
 }
 
-int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
+int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
 {
 	int error = -ESRCH;
 	struct task_struct *p;
@@ -1373,7 +1373,7 @@ int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
 	}
 }
 
-static int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
 {
 	int error;
 	rcu_read_lock();
@@ -1394,7 +1394,7 @@ static inline bool kill_as_cred_perm(const struct cred *cred,
 }
 
 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
-int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
+int kill_pid_info_as_cred(int sig, struct kernel_siginfo *info, struct pid *pid,
 			 const struct cred *cred)
 {
 	int ret = -EINVAL;
@@ -1438,7 +1438,7 @@ EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
  * is probably wrong.  Should make it like BSD or SYSV.
  */
 
-static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
+static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
 {
 	int ret;
 
@@ -1482,7 +1482,7 @@ static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
  * These are for backward compatibility with the rest of the kernel source.
  */
 
-int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
 {
 	/*
 	 * Make sure legacy kernel users don't send in bad values
@@ -1533,7 +1533,7 @@ int force_sig_fault(int sig, int code, void __user *addr
 	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
 	, struct task_struct *t)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = sig;
@@ -1556,7 +1556,7 @@ int send_sig_fault(int sig, int code, void __user *addr
 	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
 	, struct task_struct *t)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = sig;
@@ -1576,7 +1576,7 @@ int send_sig_fault(int sig, int code, void __user *addr
 
 int force_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
 	clear_siginfo(&info);
@@ -1590,7 +1590,7 @@ int force_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct
 
 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
 	clear_siginfo(&info);
@@ -1605,7 +1605,7 @@ EXPORT_SYMBOL(send_sig_mceerr);
 
 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = SIGSEGV;
@@ -1620,7 +1620,7 @@ int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
 #ifdef SEGV_PKUERR
 int force_sig_pkuerr(void __user *addr, u32 pkey)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = SIGSEGV;
@@ -1637,7 +1637,7 @@ int force_sig_pkuerr(void __user *addr, u32 pkey)
  */
 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = SIGTRAP;
@@ -1766,7 +1766,7 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
  */
 bool do_notify_parent(struct task_struct *tsk, int sig)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 	unsigned long flags;
 	struct sighand_struct *psig;
 	bool autoreap = false;
@@ -1871,7 +1871,7 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
 static void do_notify_parent_cldstop(struct task_struct *tsk,
 				     bool for_ptracer, int why)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 	unsigned long flags;
 	struct task_struct *parent;
 	struct sighand_struct *sighand;
@@ -1971,7 +1971,7 @@ static bool sigkill_pending(struct task_struct *tsk)
  * If we actually decide not to stop at all because the tracer
  * is gone, we keep current->exit_code unless clear_code.
  */
-static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
+static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
 	__releases(&current->sighand->siglock)
 	__acquires(&current->sighand->siglock)
 {
@@ -2108,7 +2108,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
 
 static void ptrace_do_notify(int signr, int exit_code, int why)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 
 	clear_siginfo(&info);
 	info.si_signo = signr;
@@ -2289,7 +2289,7 @@ static void do_jobctl_trap(void)
 	}
 }
 
-static int ptrace_signal(int signr, siginfo_t *info)
+static int ptrace_signal(int signr, kernel_siginfo_t *info)
 {
 	/*
 	 * We do not check sig_kernel_stop(signr) but set this marker
@@ -2889,14 +2889,14 @@ enum siginfo_layout siginfo_layout(int sig, int si_code)
 	return layout;
 }
 
-int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
+int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
 {
-	if (copy_to_user(to, from , sizeof(struct siginfo)))
+	if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
 		return -EFAULT;
 	return 0;
 }
 
-int copy_siginfo_from_user(siginfo_t *to, const siginfo_t __user *from)
+int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 {
 	if (copy_from_user(to, from, sizeof(struct siginfo)))
 		return -EFAULT;
@@ -2905,13 +2905,13 @@ int copy_siginfo_from_user(siginfo_t *to, const siginfo_t __user *from)
 
 #ifdef CONFIG_COMPAT
 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
-			   const struct siginfo *from)
+			   const struct kernel_siginfo *from)
 #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
 {
 	return __copy_siginfo_to_user32(to, from, in_x32_syscall());
 }
 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
-			     const struct siginfo *from, bool x32_ABI)
+			     const struct kernel_siginfo *from, bool x32_ABI)
 #endif
 {
 	struct compat_siginfo new;
@@ -2995,7 +2995,7 @@ int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
 	return 0;
 }
 
-int copy_siginfo_from_user32(struct siginfo *to,
+int copy_siginfo_from_user32(struct kernel_siginfo *to,
 			     const struct compat_siginfo __user *ufrom)
 {
 	struct compat_siginfo from;
@@ -3085,7 +3085,7 @@ int copy_siginfo_from_user32(struct siginfo *to,
  *  @info: if non-null, the signal's siginfo is returned here
  *  @ts: upper bound on process time suspension
  */
-static int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
+static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
 		    const struct timespec *ts)
 {
 	ktime_t *to = NULL, timeout = KTIME_MAX;
@@ -3149,7 +3149,7 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
 {
 	sigset_t these;
 	struct timespec ts;
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret;
 
 	/* XXX: Don't preclude handling different sized sigset_t's.  */
@@ -3181,7 +3181,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese,
 {
 	sigset_t s;
 	struct timespec t;
-	siginfo_t info;
+	kernel_siginfo_t info;
 	long ret;
 
 	if (sigsetsize != sizeof(sigset_t))
@@ -3213,7 +3213,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese,
  */
 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = sig;
@@ -3226,7 +3226,7 @@ SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
 }
 
 static int
-do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
+do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
 {
 	struct task_struct *p;
 	int error = -ESRCH;
@@ -3257,7 +3257,7 @@ do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
 
 static int do_tkill(pid_t tgid, pid_t pid, int sig)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = sig;
@@ -3304,7 +3304,7 @@ SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
 	return do_tkill(0, pid, sig);
 }
 
-static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
+static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
 {
 	/* Not even root can pretend to send signals from the kernel.
 	 * Nor can they impersonate a kill()/tgkill(), which adds source info.
@@ -3329,7 +3329,7 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret = copy_siginfo_from_user(&info, uinfo);
 	if (unlikely(ret))
 		return ret;
@@ -3342,7 +3342,7 @@ COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
 			int, sig,
 			struct compat_siginfo __user *, uinfo)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret = copy_siginfo_from_user32(&info, uinfo);
 	if (unlikely(ret))
 		return ret;
@@ -3350,7 +3350,7 @@ COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
 }
 #endif
 
-static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
+static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
 {
 	/* This is only valid for single tasks */
 	if (pid <= 0 || tgid <= 0)
@@ -3372,7 +3372,7 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret = copy_siginfo_from_user(&info, uinfo);
 	if (unlikely(ret))
 		return ret;
@@ -3386,7 +3386,7 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
 			int, sig,
 			struct compat_siginfo __user *, uinfo)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret = copy_siginfo_from_user32(&info, uinfo);
 	if (unlikely(ret))
 		return ret;
@@ -3968,10 +3968,57 @@ __weak const char *arch_vma_name(struct vm_area_struct *vma)
 	return NULL;
 }
 
-void __init signals_init(void)
+static inline void siginfo_buildtime_checks(void)
 {
 	BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
 
+	/* Verify the offsets in the two siginfos match */
+#define CHECK_OFFSET(field) \
+	BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
+
+	/* kill */
+	CHECK_OFFSET(si_pid);
+	CHECK_OFFSET(si_uid);
+
+	/* timer */
+	CHECK_OFFSET(si_tid);
+	CHECK_OFFSET(si_overrun);
+	CHECK_OFFSET(si_value);
+
+	/* rt */
+	CHECK_OFFSET(si_pid);
+	CHECK_OFFSET(si_uid);
+	CHECK_OFFSET(si_value);
+
+	/* sigchld */
+	CHECK_OFFSET(si_pid);
+	CHECK_OFFSET(si_uid);
+	CHECK_OFFSET(si_status);
+	CHECK_OFFSET(si_utime);
+	CHECK_OFFSET(si_stime);
+
+	/* sigfault */
+	CHECK_OFFSET(si_addr);
+	CHECK_OFFSET(si_addr_lsb);
+	CHECK_OFFSET(si_lower);
+	CHECK_OFFSET(si_upper);
+	CHECK_OFFSET(si_pkey);
+
+	/* sigpoll */
+	CHECK_OFFSET(si_band);
+	CHECK_OFFSET(si_fd);
+
+	/* sigsys */
+	CHECK_OFFSET(si_call_addr);
+	CHECK_OFFSET(si_syscall);
+	CHECK_OFFSET(si_arch);
+#undef CHECK_OFFSET
+}
+
+void __init signals_init(void)
+{
+	siginfo_buildtime_checks();
+
 	sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
 }
 
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 4b9127e95430..eabb4c22728d 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -308,7 +308,7 @@ static void common_hrtimer_rearm(struct k_itimer *timr)
  * To protect against the timer going away while the interrupt is queued,
  * we require that the it_requeue_pending flag be set.
  */
-void posixtimer_rearm(struct siginfo *info)
+void posixtimer_rearm(struct kernel_siginfo *info)
 {
 	struct k_itimer *timr;
 	unsigned long flags;
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 8b8b70620bbe..cbcb8ba51142 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -732,7 +732,7 @@ static int apparmor_task_setrlimit(struct task_struct *task,
 	return error;
 }
 
-static int apparmor_task_kill(struct task_struct *target, struct siginfo *info,
+static int apparmor_task_kill(struct task_struct *target, struct kernel_siginfo *info,
 			      int sig, const struct cred *cred)
 {
 	struct aa_label *cl, *tl;
diff --git a/security/security.c b/security/security.c
index 736e78da1ab9..0d504fceda8b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1147,7 +1147,7 @@ int security_task_movememory(struct task_struct *p)
 	return call_int_hook(task_movememory, 0, p);
 }
 
-int security_task_kill(struct task_struct *p, struct siginfo *info,
+int security_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 			int sig, const struct cred *cred)
 {
 	return call_int_hook(task_kill, 0, p, info, sig, cred);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ad9a9b8e9979..1b500b4c78a7 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4186,7 +4186,7 @@ static int selinux_task_movememory(struct task_struct *p)
 			    PROCESS__SETSCHED, NULL);
 }
 
-static int selinux_task_kill(struct task_struct *p, struct siginfo *info,
+static int selinux_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 				int sig, const struct cred *cred)
 {
 	u32 secid;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 340fc30ad85d..025de76af1db 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2251,7 +2251,7 @@ static int smack_task_movememory(struct task_struct *p)
  * Return 0 if write access is permitted
  *
  */
-static int smack_task_kill(struct task_struct *p, struct siginfo *info,
+static int smack_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 			   int sig, const struct cred *cred)
 {
 	struct smk_audit_info ad;
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 5/6] signal: Distinguish between kernel_siginfo and siginfo
  2018-09-25 17:19 ` [REVIEW][PATCH 5/6] signal: Distinguish between kernel_siginfo and siginfo Eric W. Biederman
@ 2018-09-25 17:19   ` Eric W. Biederman
  0 siblings, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

Linus recently observed that if we did not worry about the padding
member in struct siginfo it is only about 48 bytes, and 48 bytes is
much nicer than 128 bytes for allocating on the stack and copying
around in the kernel.

The obvious thing of only adding the padding when userspace is
including siginfo.h won't work as there are sigframe definitions in
the kernel that embed struct siginfo.

So split siginfo in two; kernel_siginfo and siginfo.  Keeping the
traditional name for the userspace definition.  While the version that
is used internally to the kernel and ultimately will not be padded to
128 bytes is called kernel_siginfo.

The definition of struct kernel_siginfo I have put in include/signal_types.h

A set of buildtime checks has been added to verify the two structures have
the same field offsets.

To make it easy to verify the change kernel_siginfo retains the same
size as siginfo.  The reduction in size comes in a following change.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/x86/include/asm/compat.h |   2 +-
 drivers/usb/core/devio.c      |   4 +-
 fs/binfmt_elf.c               |   6 +-
 fs/coredump.c                 |   2 +-
 fs/fcntl.c                    |   2 +-
 fs/signalfd.c                 |   6 +-
 include/linux/binfmts.h       |   2 +-
 include/linux/compat.h        |   4 +-
 include/linux/coredump.h      |   4 +-
 include/linux/lsm_hooks.h     |   4 +-
 include/linux/posix-timers.h  |   2 +-
 include/linux/ptrace.h        |   2 +-
 include/linux/sched.h         |   2 +-
 include/linux/sched/signal.h  |  18 ++--
 include/linux/security.h      |   6 +-
 include/linux/signal.h        |  15 ++--
 include/linux/signal_types.h  |  11 ++-
 include/trace/events/signal.h |   4 +-
 ipc/mqueue.c                  |   2 +-
 kernel/ptrace.c               |  10 +--
 kernel/seccomp.c              |   6 +-
 kernel/signal.c               | 151 ++++++++++++++++++++++------------
 kernel/time/posix-timers.c    |   2 +-
 security/apparmor/lsm.c       |   2 +-
 security/security.c           |   2 +-
 security/selinux/hooks.c      |   2 +-
 security/smack/smack_lsm.c    |   2 +-
 27 files changed, 165 insertions(+), 110 deletions(-)

diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index fb97cf7c4137..a0f46bdd9f24 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -240,6 +240,6 @@ static inline bool in_compat_syscall(void)
 
 struct compat_siginfo;
 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
-		const siginfo_t *from, bool x32_ABI);
+		const kernel_siginfo_t *from, bool x32_ABI);
 
 #endif /* _ASM_X86_COMPAT_H */
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 6ce77b33da61..c260ea8808b0 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -582,7 +582,7 @@ static void async_completed(struct urb *urb)
 {
 	struct async *as = urb->context;
 	struct usb_dev_state *ps = as->ps;
-	struct siginfo sinfo;
+	struct kernel_siginfo sinfo;
 	struct pid *pid = NULL;
 	const struct cred *cred = NULL;
 	unsigned long flags;
@@ -2599,7 +2599,7 @@ const struct file_operations usbdev_file_operations = {
 static void usbdev_remove(struct usb_device *udev)
 {
 	struct usb_dev_state *ps;
-	struct siginfo sinfo;
+	struct kernel_siginfo sinfo;
 
 	while (!list_empty(&udev->filelist)) {
 		ps = list_entry(udev->filelist.next, struct usb_dev_state, list);
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index efae2fb0930a..54207327f98f 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1580,7 +1580,7 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
 }
 
 static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
-		const siginfo_t *siginfo)
+		const kernel_siginfo_t *siginfo)
 {
 	mm_segment_t old_fs = get_fs();
 	set_fs(KERNEL_DS);
@@ -1782,7 +1782,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 
 static int fill_note_info(struct elfhdr *elf, int phdrs,
 			  struct elf_note_info *info,
-			  const siginfo_t *siginfo, struct pt_regs *regs)
+			  const kernel_siginfo_t *siginfo, struct pt_regs *regs)
 {
 	struct task_struct *dump_task = current;
 	const struct user_regset_view *view = task_user_regset_view(dump_task);
@@ -2031,7 +2031,7 @@ static int elf_note_info_init(struct elf_note_info *info)
 
 static int fill_note_info(struct elfhdr *elf, int phdrs,
 			  struct elf_note_info *info,
-			  const siginfo_t *siginfo, struct pt_regs *regs)
+			  const kernel_siginfo_t *siginfo, struct pt_regs *regs)
 {
 	struct list_head *t;
 	struct core_thread *ct;
diff --git a/fs/coredump.c b/fs/coredump.c
index 1e2c87acac9b..e42e17e55bfd 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -536,7 +536,7 @@ static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
 	return err;
 }
 
-void do_coredump(const siginfo_t *siginfo)
+void do_coredump(const kernel_siginfo_t *siginfo)
 {
 	struct core_state core_state;
 	struct core_name cn;
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 4137d96534a6..083185174c6d 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -735,7 +735,7 @@ static void send_sigio_to_task(struct task_struct *p,
 		return;
 
 	switch (signum) {
-		siginfo_t si;
+		kernel_siginfo_t si;
 		default:
 			/* Queue a rt signal with the appropriate fd as its
 			   value.  We use SI_SIGIO as the source, not 
diff --git a/fs/signalfd.c b/fs/signalfd.c
index 4fcd1498acf5..757afc7c5895 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -79,7 +79,7 @@ static __poll_t signalfd_poll(struct file *file, poll_table *wait)
  * Copied from copy_siginfo_to_user() in kernel/signal.c
  */
 static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
-			     siginfo_t const *kinfo)
+			     kernel_siginfo_t const *kinfo)
 {
 	struct signalfd_siginfo new;
 
@@ -163,7 +163,7 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
 	return sizeof(*uinfo);
 }
 
-static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, siginfo_t *info,
+static ssize_t signalfd_dequeue(struct signalfd_ctx *ctx, kernel_siginfo_t *info,
 				int nonblock)
 {
 	ssize_t ret;
@@ -215,7 +215,7 @@ static ssize_t signalfd_read(struct file *file, char __user *buf, size_t count,
 	struct signalfd_siginfo __user *siginfo;
 	int nonblock = file->f_flags & O_NONBLOCK;
 	ssize_t ret, total = 0;
-	siginfo_t info;
+	kernel_siginfo_t info;
 
 	count /= sizeof(struct signalfd_siginfo);
 	if (!count)
diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h
index c05f24fac4f6..e9f5fe69df31 100644
--- a/include/linux/binfmts.h
+++ b/include/linux/binfmts.h
@@ -78,7 +78,7 @@ struct linux_binprm {
 
 /* Function parameter for binfmt->coredump */
 struct coredump_params {
-	const siginfo_t *siginfo;
+	const kernel_siginfo_t *siginfo;
 	struct pt_regs *regs;
 	struct file *file;
 	unsigned long limit;
diff --git a/include/linux/compat.h b/include/linux/compat.h
index 1a3c4f37e908..4565d65b1776 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -452,8 +452,8 @@ long compat_get_bitmap(unsigned long *mask, const compat_ulong_t __user *umask,
 		       unsigned long bitmap_size);
 long compat_put_bitmap(compat_ulong_t __user *umask, unsigned long *mask,
 		       unsigned long bitmap_size);
-int copy_siginfo_from_user32(siginfo_t *to, const struct compat_siginfo __user *from);
-int copy_siginfo_to_user32(struct compat_siginfo __user *to, const siginfo_t *from);
+int copy_siginfo_from_user32(kernel_siginfo_t *to, const struct compat_siginfo __user *from);
+int copy_siginfo_to_user32(struct compat_siginfo __user *to, const kernel_siginfo_t *from);
 int get_compat_sigevent(struct sigevent *event,
 		const struct compat_sigevent __user *u_event);
 
diff --git a/include/linux/coredump.h b/include/linux/coredump.h
index 207aed96a5b7..abf4b4e65dbb 100644
--- a/include/linux/coredump.h
+++ b/include/linux/coredump.h
@@ -17,9 +17,9 @@ extern int dump_emit(struct coredump_params *cprm, const void *addr, int nr);
 extern int dump_align(struct coredump_params *cprm, int align);
 extern void dump_truncate(struct coredump_params *cprm);
 #ifdef CONFIG_COREDUMP
-extern void do_coredump(const siginfo_t *siginfo);
+extern void do_coredump(const kernel_siginfo_t *siginfo);
 #else
-static inline void do_coredump(const siginfo_t *siginfo) {}
+static inline void do_coredump(const kernel_siginfo_t *siginfo) {}
 #endif
 
 #endif /* _LINUX_COREDUMP_H */
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 97a020c616ad..bb40f6d34163 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -672,7 +672,7 @@
  *	Return 0 if permission is granted.
  * @task_kill:
  *	Check permission before sending signal @sig to @p.  @info can be NULL,
- *	the constant 1, or a pointer to a siginfo structure.  If @info is 1 or
+ *	the constant 1, or a pointer to a kernel_siginfo structure.  If @info is 1 or
  *	SI_FROMKERNEL(info) is true, then the signal should be viewed as coming
  *	from the kernel and should typically be permitted.
  *	SIGIO signals are handled separately by the send_sigiotask hook in
@@ -1606,7 +1606,7 @@ union security_list_options {
 	int (*task_setscheduler)(struct task_struct *p);
 	int (*task_getscheduler)(struct task_struct *p);
 	int (*task_movememory)(struct task_struct *p);
-	int (*task_kill)(struct task_struct *p, struct siginfo *info,
+	int (*task_kill)(struct task_struct *p, struct kernel_siginfo *info,
 				int sig, const struct cred *cred);
 	int (*task_prctl)(int option, unsigned long arg2, unsigned long arg3,
 				unsigned long arg4, unsigned long arg5);
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index ee7e987ea1b4..e96581ca7c9d 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -126,5 +126,5 @@ void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
 
 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
 
-void posixtimer_rearm(struct siginfo *info);
+void posixtimer_rearm(struct kernel_siginfo *info);
 #endif
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 1de2235511c8..d19a795100da 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -341,7 +341,7 @@ extern void user_single_step_report(struct pt_regs *regs);
 #else
 static inline void user_single_step_report(struct pt_regs *regs)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	clear_siginfo(&info);
 	info.si_signo = SIGTRAP;
 	info.si_errno = 0;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 977cb57d7bc9..2ba88082e1ef 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -960,7 +960,7 @@ struct task_struct {
 
 	/* Ptrace state: */
 	unsigned long			ptrace_message;
-	siginfo_t			*last_siginfo;
+	kernel_siginfo_t		*last_siginfo;
 
 	struct task_io_accounting	ioac;
 #ifdef CONFIG_TASK_XACCT
diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h
index 9e07f3521549..13789d10a50e 100644
--- a/include/linux/sched/signal.h
+++ b/include/linux/sched/signal.h
@@ -270,12 +270,12 @@ static inline int signal_group_exit(const struct signal_struct *sig)
 extern void flush_signals(struct task_struct *);
 extern void ignore_signals(struct task_struct *);
 extern void flush_signal_handlers(struct task_struct *, int force_default);
-extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info);
+extern int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info);
 
 static inline int kernel_dequeue_signal(void)
 {
 	struct task_struct *tsk = current;
-	siginfo_t __info;
+	kernel_siginfo_t __info;
 	int ret;
 
 	spin_lock_irq(&tsk->sighand->siglock);
@@ -322,12 +322,12 @@ int force_sig_pkuerr(void __user *addr, u32 pkey);
 
 int force_sig_ptrace_errno_trap(int errno, void __user *addr);
 
-extern int send_sig_info(int, struct siginfo *, struct task_struct *);
+extern int send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
 extern void force_sigsegv(int sig, struct task_struct *p);
-extern int force_sig_info(int, struct siginfo *, struct task_struct *);
-extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
-extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
-extern int kill_pid_info_as_cred(int, struct siginfo *, struct pid *,
+extern int force_sig_info(int, struct kernel_siginfo *, struct task_struct *);
+extern int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp);
+extern int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid);
+extern int kill_pid_info_as_cred(int, struct kernel_siginfo *, struct pid *,
 				const struct cred *);
 extern int kill_pgrp(struct pid *pid, int sig, int priv);
 extern int kill_pid(struct pid *pid, int sig, int priv);
@@ -475,8 +475,8 @@ static inline int kill_cad_pid(int sig, int priv)
 }
 
 /* These can be the second arg to send_sig_info/send_group_sig_info.  */
-#define SEND_SIG_NOINFO ((struct siginfo *) 0)
-#define SEND_SIG_PRIV	((struct siginfo *) 1)
+#define SEND_SIG_NOINFO ((struct kernel_siginfo *) 0)
+#define SEND_SIG_PRIV	((struct kernel_siginfo *) 1)
 
 /*
  * True if we are on the alternate signal stack.
diff --git a/include/linux/security.h b/include/linux/security.h
index 75f4156c84d7..d170a5b031f3 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -35,7 +35,7 @@
 struct linux_binprm;
 struct cred;
 struct rlimit;
-struct siginfo;
+struct kernel_siginfo;
 struct sembuf;
 struct kern_ipc_perm;
 struct audit_context;
@@ -361,7 +361,7 @@ int security_task_setrlimit(struct task_struct *p, unsigned int resource,
 int security_task_setscheduler(struct task_struct *p);
 int security_task_getscheduler(struct task_struct *p);
 int security_task_movememory(struct task_struct *p);
-int security_task_kill(struct task_struct *p, struct siginfo *info,
+int security_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 			int sig, const struct cred *cred);
 int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
 			unsigned long arg4, unsigned long arg5);
@@ -1020,7 +1020,7 @@ static inline int security_task_movememory(struct task_struct *p)
 }
 
 static inline int security_task_kill(struct task_struct *p,
-				     struct siginfo *info, int sig,
+				     struct kernel_siginfo *info, int sig,
 				     const struct cred *cred)
 {
 	return 0;
diff --git a/include/linux/signal.h b/include/linux/signal.h
index de94c159bfb0..70031b10b918 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -11,18 +11,19 @@ struct task_struct;
 /* for sysctl */
 extern int print_fatal_signals;
 
-static inline void copy_siginfo(struct siginfo *to, const struct siginfo *from)
+static inline void copy_siginfo(kernel_siginfo_t *to,
+				const kernel_siginfo_t *from)
 {
 	memcpy(to, from, sizeof(*to));
 }
 
-static inline void clear_siginfo(struct siginfo *info)
+static inline void clear_siginfo(kernel_siginfo_t *info)
 {
 	memset(info, 0, sizeof(*info));
 }
 
-int copy_siginfo_to_user(struct siginfo __user *to, const struct siginfo *from);
-int copy_siginfo_from_user(struct siginfo *to, const struct siginfo __user *from);
+int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
+int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
 
 enum siginfo_layout {
 	SIL_KILL,
@@ -258,11 +259,11 @@ struct pt_regs;
 enum pid_type;
 
 extern int next_signal(struct sigpending *pending, sigset_t *mask);
-extern int do_send_sig_info(int sig, struct siginfo *info,
+extern int do_send_sig_info(int sig, struct kernel_siginfo *info,
 				struct task_struct *p, enum pid_type type);
-extern int group_send_sig_info(int sig, struct siginfo *info,
+extern int group_send_sig_info(int sig, struct kernel_siginfo *info,
 			       struct task_struct *p, enum pid_type type);
-extern int __group_send_sig_info(int, struct siginfo *, struct task_struct *);
+extern int __group_send_sig_info(int, struct kernel_siginfo *, struct task_struct *);
 extern int sigprocmask(int, sigset_t *, sigset_t *);
 extern void set_current_blocked(sigset_t *);
 extern void __set_current_blocked(const sigset_t *);
diff --git a/include/linux/signal_types.h b/include/linux/signal_types.h
index 222ae696000b..2a40a9c5e4ad 100644
--- a/include/linux/signal_types.h
+++ b/include/linux/signal_types.h
@@ -9,6 +9,13 @@
 #include <linux/list.h>
 #include <uapi/linux/signal.h>
 
+typedef struct kernel_siginfo {
+	union {
+		__SIGINFO;
+		int _si_pad[SI_MAX_SIZE/sizeof(int)];
+	};
+} kernel_siginfo_t;
+
 /*
  * Real Time signals may be queued.
  */
@@ -16,7 +23,7 @@
 struct sigqueue {
 	struct list_head list;
 	int flags;
-	siginfo_t info;
+	kernel_siginfo_t info;
 	struct user_struct *user;
 };
 
@@ -60,7 +67,7 @@ struct old_sigaction {
 
 struct ksignal {
 	struct k_sigaction ka;
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int sig;
 };
 
diff --git a/include/trace/events/signal.h b/include/trace/events/signal.h
index 3deeed50ffd0..1db7e4b07c01 100644
--- a/include/trace/events/signal.h
+++ b/include/trace/events/signal.h
@@ -49,7 +49,7 @@ enum {
  */
 TRACE_EVENT(signal_generate,
 
-	TP_PROTO(int sig, struct siginfo *info, struct task_struct *task,
+	TP_PROTO(int sig, struct kernel_siginfo *info, struct task_struct *task,
 			int group, int result),
 
 	TP_ARGS(sig, info, task, group, result),
@@ -95,7 +95,7 @@ TRACE_EVENT(signal_generate,
  */
 TRACE_EVENT(signal_deliver,
 
-	TP_PROTO(int sig, struct siginfo *info, struct k_sigaction *ka),
+	TP_PROTO(int sig, struct kernel_siginfo *info, struct k_sigaction *ka),
 
 	TP_ARGS(sig, info, ka),
 
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index c0d58f390c3b..cc41de3b8deb 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -655,7 +655,7 @@ static void __do_notify(struct mqueue_inode_info *info)
 	 * synchronously. */
 	if (info->notify_owner &&
 	    info->attr.mq_curmsgs == 1) {
-		struct siginfo sig_i;
+		struct kernel_siginfo sig_i;
 		switch (info->notify.sigev_notify) {
 		case SIGEV_NONE:
 			break;
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index a807ff5cc1a9..c2cee9db5204 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -651,7 +651,7 @@ static int ptrace_setoptions(struct task_struct *child, unsigned long data)
 	return 0;
 }
 
-static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
+static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
 {
 	unsigned long flags;
 	int error = -ESRCH;
@@ -667,7 +667,7 @@ static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
 	return error;
 }
 
-static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
+static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
 {
 	unsigned long flags;
 	int error = -ESRCH;
@@ -709,7 +709,7 @@ static int ptrace_peek_siginfo(struct task_struct *child,
 		pending = &child->pending;
 
 	for (i = 0; i < arg.nr; ) {
-		siginfo_t info;
+		kernel_siginfo_t info;
 		s32 off = arg.off + i;
 
 		spin_lock_irq(&child->sighand->siglock);
@@ -885,7 +885,7 @@ int ptrace_request(struct task_struct *child, long request,
 {
 	bool seized = child->ptrace & PT_SEIZED;
 	int ret = -EIO;
-	siginfo_t siginfo, *si;
+	kernel_siginfo_t siginfo, *si;
 	void __user *datavp = (void __user *) data;
 	unsigned long __user *datalp = datavp;
 	unsigned long flags;
@@ -1180,7 +1180,7 @@ int compat_ptrace_request(struct task_struct *child, compat_long_t request,
 {
 	compat_ulong_t __user *datap = compat_ptr(data);
 	compat_ulong_t word;
-	siginfo_t siginfo;
+	kernel_siginfo_t siginfo;
 	int ret;
 
 	switch (request) {
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index fd023ac24e10..4d7809cdd27d 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -522,7 +522,7 @@ void put_seccomp_filter(struct task_struct *tsk)
 	__put_seccomp_filter(tsk->seccomp.filter);
 }
 
-static void seccomp_init_siginfo(siginfo_t *info, int syscall, int reason)
+static void seccomp_init_siginfo(kernel_siginfo_t *info, int syscall, int reason)
 {
 	clear_siginfo(info);
 	info->si_signo = SIGSYS;
@@ -542,7 +542,7 @@ static void seccomp_init_siginfo(siginfo_t *info, int syscall, int reason)
  */
 static void seccomp_send_sigsys(int syscall, int reason)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 	seccomp_init_siginfo(&info, syscall, reason);
 	force_sig_info(SIGSYS, &info, current);
 }
@@ -747,7 +747,7 @@ static int __seccomp_filter(int this_syscall, const struct seccomp_data *sd,
 		/* Dump core only if this is the last remaining thread. */
 		if (action == SECCOMP_RET_KILL_PROCESS ||
 		    get_nr_threads(current) == 1) {
-			siginfo_t info;
+			kernel_siginfo_t info;
 
 			/* Show the original registers in the dump. */
 			syscall_rollback(current, task_pt_regs(current));
diff --git a/kernel/signal.c b/kernel/signal.c
index c0e289e62d77..161cad4e448c 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -549,7 +549,7 @@ bool unhandled_signal(struct task_struct *tsk, int sig)
 	return !tsk->ptrace;
 }
 
-static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
+static void collect_signal(int sig, struct sigpending *list, kernel_siginfo_t *info,
 			   bool *resched_timer)
 {
 	struct sigqueue *q, *first = NULL;
@@ -595,7 +595,7 @@ static void collect_signal(int sig, struct sigpending *list, siginfo_t *info,
 }
 
 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
-			siginfo_t *info, bool *resched_timer)
+			kernel_siginfo_t *info, bool *resched_timer)
 {
 	int sig = next_signal(pending, mask);
 
@@ -610,7 +610,7 @@ static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
  *
  * All callers have to hold the siglock.
  */
-int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
+int dequeue_signal(struct task_struct *tsk, sigset_t *mask, kernel_siginfo_t *info)
 {
 	bool resched_timer = false;
 	int signr;
@@ -737,12 +737,12 @@ static void flush_sigqueue_mask(sigset_t *mask, struct sigpending *s)
 	}
 }
 
-static inline int is_si_special(const struct siginfo *info)
+static inline int is_si_special(const struct kernel_siginfo *info)
 {
 	return info <= SEND_SIG_PRIV;
 }
 
-static inline bool si_fromuser(const struct siginfo *info)
+static inline bool si_fromuser(const struct kernel_siginfo *info)
 {
 	return info == SEND_SIG_NOINFO ||
 		(!is_si_special(info) && SI_FROMUSER(info));
@@ -767,7 +767,7 @@ static bool kill_ok_by_cred(struct task_struct *t)
  * Bad permissions for sending the signal
  * - the caller must hold the RCU read lock
  */
-static int check_kill_permission(int sig, struct siginfo *info,
+static int check_kill_permission(int sig, struct kernel_siginfo *info,
 				 struct task_struct *t)
 {
 	struct pid *sid;
@@ -1010,7 +1010,7 @@ static inline bool legacy_queue(struct sigpending *signals, int sig)
 }
 
 #ifdef CONFIG_USER_NS
-static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t)
 {
 	if (current_user_ns() == task_cred_xxx(t, user_ns))
 		return;
@@ -1024,13 +1024,13 @@ static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_str
 	rcu_read_unlock();
 }
 #else
-static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+static inline void userns_fixup_signal_uid(struct kernel_siginfo *info, struct task_struct *t)
 {
 	return;
 }
 #endif
 
-static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
+static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
 			enum pid_type type, int from_ancestor_ns)
 {
 	struct sigpending *pending;
@@ -1150,7 +1150,7 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
 	return ret;
 }
 
-static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
+static int send_signal(int sig, struct kernel_siginfo *info, struct task_struct *t,
 			enum pid_type type)
 {
 	int from_ancestor_ns = 0;
@@ -1197,12 +1197,12 @@ static int __init setup_print_fatal_signals(char *str)
 __setup("print-fatal-signals=", setup_print_fatal_signals);
 
 int
-__group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+__group_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
 {
 	return send_signal(sig, info, p, PIDTYPE_TGID);
 }
 
-int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
+int do_send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p,
 			enum pid_type type)
 {
 	unsigned long flags;
@@ -1228,7 +1228,7 @@ int do_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
  * that is why we also clear SIGNAL_UNKILLABLE.
  */
 int
-force_sig_info(int sig, struct siginfo *info, struct task_struct *t)
+force_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *t)
 {
 	unsigned long int flags;
 	int ret, blocked, ignored;
@@ -1316,8 +1316,8 @@ struct sighand_struct *__lock_task_sighand(struct task_struct *tsk,
 /*
  * send signal info to all the members of a group
  */
-int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
-			enum pid_type type)
+int group_send_sig_info(int sig, struct kernel_siginfo *info,
+			struct task_struct *p, enum pid_type type)
 {
 	int ret;
 
@@ -1336,7 +1336,7 @@ int group_send_sig_info(int sig, struct siginfo *info, struct task_struct *p,
  * control characters do (^C, ^Z etc)
  * - the caller must hold at least a readlock on tasklist_lock
  */
-int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
+int __kill_pgrp_info(int sig, struct kernel_siginfo *info, struct pid *pgrp)
 {
 	struct task_struct *p = NULL;
 	int retval, success;
@@ -1351,7 +1351,7 @@ int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp)
 	return success ? 0 : retval;
 }
 
-int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
+int kill_pid_info(int sig, struct kernel_siginfo *info, struct pid *pid)
 {
 	int error = -ESRCH;
 	struct task_struct *p;
@@ -1373,7 +1373,7 @@ int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
 	}
 }
 
-static int kill_proc_info(int sig, struct siginfo *info, pid_t pid)
+static int kill_proc_info(int sig, struct kernel_siginfo *info, pid_t pid)
 {
 	int error;
 	rcu_read_lock();
@@ -1394,7 +1394,7 @@ static inline bool kill_as_cred_perm(const struct cred *cred,
 }
 
 /* like kill_pid_info(), but doesn't use uid/euid of "current" */
-int kill_pid_info_as_cred(int sig, struct siginfo *info, struct pid *pid,
+int kill_pid_info_as_cred(int sig, struct kernel_siginfo *info, struct pid *pid,
 			 const struct cred *cred)
 {
 	int ret = -EINVAL;
@@ -1438,7 +1438,7 @@ EXPORT_SYMBOL_GPL(kill_pid_info_as_cred);
  * is probably wrong.  Should make it like BSD or SYSV.
  */
 
-static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
+static int kill_something_info(int sig, struct kernel_siginfo *info, pid_t pid)
 {
 	int ret;
 
@@ -1482,7 +1482,7 @@ static int kill_something_info(int sig, struct siginfo *info, pid_t pid)
  * These are for backward compatibility with the rest of the kernel source.
  */
 
-int send_sig_info(int sig, struct siginfo *info, struct task_struct *p)
+int send_sig_info(int sig, struct kernel_siginfo *info, struct task_struct *p)
 {
 	/*
 	 * Make sure legacy kernel users don't send in bad values
@@ -1533,7 +1533,7 @@ int force_sig_fault(int sig, int code, void __user *addr
 	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
 	, struct task_struct *t)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = sig;
@@ -1556,7 +1556,7 @@ int send_sig_fault(int sig, int code, void __user *addr
 	___ARCH_SI_IA64(int imm, unsigned int flags, unsigned long isr)
 	, struct task_struct *t)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = sig;
@@ -1576,7 +1576,7 @@ int send_sig_fault(int sig, int code, void __user *addr
 
 int force_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
 	clear_siginfo(&info);
@@ -1590,7 +1590,7 @@ int force_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct
 
 int send_sig_mceerr(int code, void __user *addr, short lsb, struct task_struct *t)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	WARN_ON((code != BUS_MCEERR_AO) && (code != BUS_MCEERR_AR));
 	clear_siginfo(&info);
@@ -1605,7 +1605,7 @@ EXPORT_SYMBOL(send_sig_mceerr);
 
 int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = SIGSEGV;
@@ -1620,7 +1620,7 @@ int force_sig_bnderr(void __user *addr, void __user *lower, void __user *upper)
 #ifdef SEGV_PKUERR
 int force_sig_pkuerr(void __user *addr, u32 pkey)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = SIGSEGV;
@@ -1637,7 +1637,7 @@ int force_sig_pkuerr(void __user *addr, u32 pkey)
  */
 int force_sig_ptrace_errno_trap(int errno, void __user *addr)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = SIGTRAP;
@@ -1766,7 +1766,7 @@ int send_sigqueue(struct sigqueue *q, struct pid *pid, enum pid_type type)
  */
 bool do_notify_parent(struct task_struct *tsk, int sig)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 	unsigned long flags;
 	struct sighand_struct *psig;
 	bool autoreap = false;
@@ -1871,7 +1871,7 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
 static void do_notify_parent_cldstop(struct task_struct *tsk,
 				     bool for_ptracer, int why)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 	unsigned long flags;
 	struct task_struct *parent;
 	struct sighand_struct *sighand;
@@ -1971,7 +1971,7 @@ static bool sigkill_pending(struct task_struct *tsk)
  * If we actually decide not to stop at all because the tracer
  * is gone, we keep current->exit_code unless clear_code.
  */
-static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
+static void ptrace_stop(int exit_code, int why, int clear_code, kernel_siginfo_t *info)
 	__releases(&current->sighand->siglock)
 	__acquires(&current->sighand->siglock)
 {
@@ -2108,7 +2108,7 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
 
 static void ptrace_do_notify(int signr, int exit_code, int why)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 
 	clear_siginfo(&info);
 	info.si_signo = signr;
@@ -2289,7 +2289,7 @@ static void do_jobctl_trap(void)
 	}
 }
 
-static int ptrace_signal(int signr, siginfo_t *info)
+static int ptrace_signal(int signr, kernel_siginfo_t *info)
 {
 	/*
 	 * We do not check sig_kernel_stop(signr) but set this marker
@@ -2889,14 +2889,14 @@ enum siginfo_layout siginfo_layout(int sig, int si_code)
 	return layout;
 }
 
-int copy_siginfo_to_user(siginfo_t __user *to, const siginfo_t *from)
+int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
 {
-	if (copy_to_user(to, from , sizeof(struct siginfo)))
+	if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
 		return -EFAULT;
 	return 0;
 }
 
-int copy_siginfo_from_user(siginfo_t *to, const siginfo_t __user *from)
+int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 {
 	if (copy_from_user(to, from, sizeof(struct siginfo)))
 		return -EFAULT;
@@ -2905,13 +2905,13 @@ int copy_siginfo_from_user(siginfo_t *to, const siginfo_t __user *from)
 
 #ifdef CONFIG_COMPAT
 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
-			   const struct siginfo *from)
+			   const struct kernel_siginfo *from)
 #if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
 {
 	return __copy_siginfo_to_user32(to, from, in_x32_syscall());
 }
 int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
-			     const struct siginfo *from, bool x32_ABI)
+			     const struct kernel_siginfo *from, bool x32_ABI)
 #endif
 {
 	struct compat_siginfo new;
@@ -2995,7 +2995,7 @@ int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
 	return 0;
 }
 
-int copy_siginfo_from_user32(struct siginfo *to,
+int copy_siginfo_from_user32(struct kernel_siginfo *to,
 			     const struct compat_siginfo __user *ufrom)
 {
 	struct compat_siginfo from;
@@ -3085,7 +3085,7 @@ int copy_siginfo_from_user32(struct siginfo *to,
  *  @info: if non-null, the signal's siginfo is returned here
  *  @ts: upper bound on process time suspension
  */
-static int do_sigtimedwait(const sigset_t *which, siginfo_t *info,
+static int do_sigtimedwait(const sigset_t *which, kernel_siginfo_t *info,
 		    const struct timespec *ts)
 {
 	ktime_t *to = NULL, timeout = KTIME_MAX;
@@ -3149,7 +3149,7 @@ SYSCALL_DEFINE4(rt_sigtimedwait, const sigset_t __user *, uthese,
 {
 	sigset_t these;
 	struct timespec ts;
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret;
 
 	/* XXX: Don't preclude handling different sized sigset_t's.  */
@@ -3181,7 +3181,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese,
 {
 	sigset_t s;
 	struct timespec t;
-	siginfo_t info;
+	kernel_siginfo_t info;
 	long ret;
 
 	if (sigsetsize != sizeof(sigset_t))
@@ -3213,7 +3213,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigtimedwait, compat_sigset_t __user *, uthese,
  */
 SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = sig;
@@ -3226,7 +3226,7 @@ SYSCALL_DEFINE2(kill, pid_t, pid, int, sig)
 }
 
 static int
-do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
+do_send_specific(pid_t tgid, pid_t pid, int sig, struct kernel_siginfo *info)
 {
 	struct task_struct *p;
 	int error = -ESRCH;
@@ -3257,7 +3257,7 @@ do_send_specific(pid_t tgid, pid_t pid, int sig, struct siginfo *info)
 
 static int do_tkill(pid_t tgid, pid_t pid, int sig)
 {
-	struct siginfo info;
+	struct kernel_siginfo info;
 
 	clear_siginfo(&info);
 	info.si_signo = sig;
@@ -3304,7 +3304,7 @@ SYSCALL_DEFINE2(tkill, pid_t, pid, int, sig)
 	return do_tkill(0, pid, sig);
 }
 
-static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
+static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
 {
 	/* Not even root can pretend to send signals from the kernel.
 	 * Nor can they impersonate a kill()/tgkill(), which adds source info.
@@ -3329,7 +3329,7 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
 SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret = copy_siginfo_from_user(&info, uinfo);
 	if (unlikely(ret))
 		return ret;
@@ -3342,7 +3342,7 @@ COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
 			int, sig,
 			struct compat_siginfo __user *, uinfo)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret = copy_siginfo_from_user32(&info, uinfo);
 	if (unlikely(ret))
 		return ret;
@@ -3350,7 +3350,7 @@ COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
 }
 #endif
 
-static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
+static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t *info)
 {
 	/* This is only valid for single tasks */
 	if (pid <= 0 || tgid <= 0)
@@ -3372,7 +3372,7 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
 SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret = copy_siginfo_from_user(&info, uinfo);
 	if (unlikely(ret))
 		return ret;
@@ -3386,7 +3386,7 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
 			int, sig,
 			struct compat_siginfo __user *, uinfo)
 {
-	siginfo_t info;
+	kernel_siginfo_t info;
 	int ret = copy_siginfo_from_user32(&info, uinfo);
 	if (unlikely(ret))
 		return ret;
@@ -3968,10 +3968,57 @@ __weak const char *arch_vma_name(struct vm_area_struct *vma)
 	return NULL;
 }
 
-void __init signals_init(void)
+static inline void siginfo_buildtime_checks(void)
 {
 	BUILD_BUG_ON(sizeof(struct siginfo) != SI_MAX_SIZE);
 
+	/* Verify the offsets in the two siginfos match */
+#define CHECK_OFFSET(field) \
+	BUILD_BUG_ON(offsetof(siginfo_t, field) != offsetof(kernel_siginfo_t, field))
+
+	/* kill */
+	CHECK_OFFSET(si_pid);
+	CHECK_OFFSET(si_uid);
+
+	/* timer */
+	CHECK_OFFSET(si_tid);
+	CHECK_OFFSET(si_overrun);
+	CHECK_OFFSET(si_value);
+
+	/* rt */
+	CHECK_OFFSET(si_pid);
+	CHECK_OFFSET(si_uid);
+	CHECK_OFFSET(si_value);
+
+	/* sigchld */
+	CHECK_OFFSET(si_pid);
+	CHECK_OFFSET(si_uid);
+	CHECK_OFFSET(si_status);
+	CHECK_OFFSET(si_utime);
+	CHECK_OFFSET(si_stime);
+
+	/* sigfault */
+	CHECK_OFFSET(si_addr);
+	CHECK_OFFSET(si_addr_lsb);
+	CHECK_OFFSET(si_lower);
+	CHECK_OFFSET(si_upper);
+	CHECK_OFFSET(si_pkey);
+
+	/* sigpoll */
+	CHECK_OFFSET(si_band);
+	CHECK_OFFSET(si_fd);
+
+	/* sigsys */
+	CHECK_OFFSET(si_call_addr);
+	CHECK_OFFSET(si_syscall);
+	CHECK_OFFSET(si_arch);
+#undef CHECK_OFFSET
+}
+
+void __init signals_init(void)
+{
+	siginfo_buildtime_checks();
+
 	sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
 }
 
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 4b9127e95430..eabb4c22728d 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -308,7 +308,7 @@ static void common_hrtimer_rearm(struct k_itimer *timr)
  * To protect against the timer going away while the interrupt is queued,
  * we require that the it_requeue_pending flag be set.
  */
-void posixtimer_rearm(struct siginfo *info)
+void posixtimer_rearm(struct kernel_siginfo *info)
 {
 	struct k_itimer *timr;
 	unsigned long flags;
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 8b8b70620bbe..cbcb8ba51142 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -732,7 +732,7 @@ static int apparmor_task_setrlimit(struct task_struct *task,
 	return error;
 }
 
-static int apparmor_task_kill(struct task_struct *target, struct siginfo *info,
+static int apparmor_task_kill(struct task_struct *target, struct kernel_siginfo *info,
 			      int sig, const struct cred *cred)
 {
 	struct aa_label *cl, *tl;
diff --git a/security/security.c b/security/security.c
index 736e78da1ab9..0d504fceda8b 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1147,7 +1147,7 @@ int security_task_movememory(struct task_struct *p)
 	return call_int_hook(task_movememory, 0, p);
 }
 
-int security_task_kill(struct task_struct *p, struct siginfo *info,
+int security_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 			int sig, const struct cred *cred)
 {
 	return call_int_hook(task_kill, 0, p, info, sig, cred);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index ad9a9b8e9979..1b500b4c78a7 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4186,7 +4186,7 @@ static int selinux_task_movememory(struct task_struct *p)
 			    PROCESS__SETSCHED, NULL);
 }
 
-static int selinux_task_kill(struct task_struct *p, struct siginfo *info,
+static int selinux_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 				int sig, const struct cred *cred)
 {
 	u32 secid;
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 340fc30ad85d..025de76af1db 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2251,7 +2251,7 @@ static int smack_task_movememory(struct task_struct *p)
  * Return 0 if write access is permitted
  *
  */
-static int smack_task_kill(struct task_struct *p, struct siginfo *info,
+static int smack_task_kill(struct task_struct *p, struct kernel_siginfo *info,
 			   int sig, const struct cred *cred)
 {
 	struct smk_audit_info ad;
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 6/6] signal: Use a smaller struct siginfo in the kernel
  2018-09-25 17:16 [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure Eric W. Biederman
                   ` (5 preceding siblings ...)
  2018-09-25 17:19 ` [REVIEW][PATCH 5/6] signal: Distinguish between kernel_siginfo and siginfo Eric W. Biederman
@ 2018-09-25 17:19 ` Eric W. Biederman
  2018-09-25 17:19   ` Eric W. Biederman
  6 siblings, 1 reply; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

We reserve 128 bytes for struct siginfo but only use about 48 bytes on
64bit and 32 bytes on 32bit.  Someday we might use more but it is unlikely
to be anytime soon.

Userspace seems content with just enough bytes of siginfo to implement
sigqueue.  Or in the case of checkpoint/restart reinjecting signals
the kernel has sent.

Reducing the stack footprint and the work to copy siginfo around from
2 cachelines to 1 cachelines seems worth doing even if I don't have
benchmarks to show a performance difference.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 include/linux/signal.h       |  2 +
 include/linux/signal_types.h |  5 +--
 kernel/signal.c              | 82 ++++++++++++++++++++++++++++--------
 3 files changed, 67 insertions(+), 22 deletions(-)

diff --git a/include/linux/signal.h b/include/linux/signal.h
index 70031b10b918..706a499d1eb1 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -22,6 +22,8 @@ static inline void clear_siginfo(kernel_siginfo_t *info)
 	memset(info, 0, sizeof(*info));
 }
 
+#define SI_EXPANSION_SIZE (sizeof(struct siginfo) - sizeof(struct kernel_siginfo))
+
 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
 
diff --git a/include/linux/signal_types.h b/include/linux/signal_types.h
index 2a40a9c5e4ad..f8a90ae9c6ec 100644
--- a/include/linux/signal_types.h
+++ b/include/linux/signal_types.h
@@ -10,10 +10,7 @@
 #include <uapi/linux/signal.h>
 
 typedef struct kernel_siginfo {
-	union {
-		__SIGINFO;
-		int _si_pad[SI_MAX_SIZE/sizeof(int)];
-	};
+	__SIGINFO;
 } kernel_siginfo_t;
 
 /*
diff --git a/kernel/signal.c b/kernel/signal.c
index 161cad4e448c..1c2dd117fee0 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2844,27 +2844,48 @@ COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
 }
 #endif
 
+static const struct {
+	unsigned char limit, layout;
+} sig_sicodes[] = {
+	[SIGILL]  = { NSIGILL,  SIL_FAULT },
+	[SIGFPE]  = { NSIGFPE,  SIL_FAULT },
+	[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
+	[SIGBUS]  = { NSIGBUS,  SIL_FAULT },
+	[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
+#if defined(SIGEMT)
+	[SIGEMT]  = { NSIGEMT,  SIL_FAULT },
+#endif
+	[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
+	[SIGPOLL] = { NSIGPOLL, SIL_POLL },
+	[SIGSYS]  = { NSIGSYS,  SIL_SYS },
+};
+
+static bool known_siginfo_layout(int sig, int si_code)
+{
+	if (si_code == SI_KERNEL)
+		return true;
+	else if ((si_code > SI_USER)) {
+		if (sig_specific_sicodes(sig)) {
+			if (si_code <= sig_sicodes[sig].limit)
+				return true;
+		}
+		else if (si_code <= NSIGPOLL)
+			return true;
+	}
+	else if (si_code >= SI_DETHREAD)
+		return true;
+	else if (si_code == SI_ASYNCNL)
+		return true;
+	return false;
+}
+
 enum siginfo_layout siginfo_layout(int sig, int si_code)
 {
 	enum siginfo_layout layout = SIL_KILL;
 	if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
-		static const struct {
-			unsigned char limit, layout;
-		} filter[] = {
-			[SIGILL]  = { NSIGILL,  SIL_FAULT },
-			[SIGFPE]  = { NSIGFPE,  SIL_FAULT },
-			[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
-			[SIGBUS]  = { NSIGBUS,  SIL_FAULT },
-			[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
-#if defined(SIGEMT)
-			[SIGEMT]  = { NSIGEMT,  SIL_FAULT },
-#endif
-			[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
-			[SIGPOLL] = { NSIGPOLL, SIL_POLL },
-			[SIGSYS]  = { NSIGSYS,  SIL_SYS },
-		};
-		if ((sig < ARRAY_SIZE(filter)) && (si_code <= filter[sig].limit)) {
-			layout = filter[sig].layout;
+		if ((sig < ARRAY_SIZE(sig_sicodes)) &&
+		    (si_code <= sig_sicodes[sig].limit)) {
+			layout = sig_sicodes[sig].layout;
 			/* Handle the exceptions */
 			if ((sig == SIGBUS) &&
 			    (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
@@ -2889,17 +2910,42 @@ enum siginfo_layout siginfo_layout(int sig, int si_code)
 	return layout;
 }
 
+static inline char __user *si_expansion(const siginfo_t __user *info)
+{
+	return ((char __user *)info) + sizeof(struct kernel_siginfo);
+}
+
 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
 {
+	char __user *expansion = si_expansion(to);
 	if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
 		return -EFAULT;
+	if (clear_user(expansion, SI_EXPANSION_SIZE))
+		return -EFAULT;
 	return 0;
 }
 
 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 {
-	if (copy_from_user(to, from, sizeof(struct siginfo)))
+	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
 		return -EFAULT;
+	if (unlikely(!known_siginfo_layout(to->si_signo, to->si_code))) {
+		char __user *expansion = si_expansion(from);
+		char buf[SI_EXPANSION_SIZE];
+		int i;
+		/*
+		 * An unknown si_code might need more than
+		 * sizeof(struct kernel_siginfo) bytes.  Verify all of the
+		 * extra bytes are 0.  This guarantees copy_siginfo_to_user
+		 * will return this data to userspace exactly.
+		 */
+		if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
+			return -EFAULT;
+		for (i = 0; i < SI_EXPANSION_SIZE; i++) {
+			if (buf[i] != 0)
+				return -E2BIG;
+		}
+	}
 	return 0;
 }
 
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 6/6] signal: Use a smaller struct siginfo in the kernel
  2018-09-25 17:19 ` [REVIEW][PATCH 6/6] signal: Use a smaller struct siginfo in the kernel Eric W. Biederman
@ 2018-09-25 17:19   ` Eric W. Biederman
  0 siblings, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-09-25 17:19 UTC (permalink / raw)
  To: linux-kernel
  Cc: linux-api, linux-arch, Oleg Nesterov, Linus Torvalds, Eric W. Biederman

We reserve 128 bytes for struct siginfo but only use about 48 bytes on
64bit and 32 bytes on 32bit.  Someday we might use more but it is unlikely
to be anytime soon.

Userspace seems content with just enough bytes of siginfo to implement
sigqueue.  Or in the case of checkpoint/restart reinjecting signals
the kernel has sent.

Reducing the stack footprint and the work to copy siginfo around from
2 cachelines to 1 cachelines seems worth doing even if I don't have
benchmarks to show a performance difference.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 include/linux/signal.h       |  2 +
 include/linux/signal_types.h |  5 +--
 kernel/signal.c              | 82 ++++++++++++++++++++++++++++--------
 3 files changed, 67 insertions(+), 22 deletions(-)

diff --git a/include/linux/signal.h b/include/linux/signal.h
index 70031b10b918..706a499d1eb1 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -22,6 +22,8 @@ static inline void clear_siginfo(kernel_siginfo_t *info)
 	memset(info, 0, sizeof(*info));
 }
 
+#define SI_EXPANSION_SIZE (sizeof(struct siginfo) - sizeof(struct kernel_siginfo))
+
 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from);
 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from);
 
diff --git a/include/linux/signal_types.h b/include/linux/signal_types.h
index 2a40a9c5e4ad..f8a90ae9c6ec 100644
--- a/include/linux/signal_types.h
+++ b/include/linux/signal_types.h
@@ -10,10 +10,7 @@
 #include <uapi/linux/signal.h>
 
 typedef struct kernel_siginfo {
-	union {
-		__SIGINFO;
-		int _si_pad[SI_MAX_SIZE/sizeof(int)];
-	};
+	__SIGINFO;
 } kernel_siginfo_t;
 
 /*
diff --git a/kernel/signal.c b/kernel/signal.c
index 161cad4e448c..1c2dd117fee0 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2844,27 +2844,48 @@ COMPAT_SYSCALL_DEFINE2(rt_sigpending, compat_sigset_t __user *, uset,
 }
 #endif
 
+static const struct {
+	unsigned char limit, layout;
+} sig_sicodes[] = {
+	[SIGILL]  = { NSIGILL,  SIL_FAULT },
+	[SIGFPE]  = { NSIGFPE,  SIL_FAULT },
+	[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
+	[SIGBUS]  = { NSIGBUS,  SIL_FAULT },
+	[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
+#if defined(SIGEMT)
+	[SIGEMT]  = { NSIGEMT,  SIL_FAULT },
+#endif
+	[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
+	[SIGPOLL] = { NSIGPOLL, SIL_POLL },
+	[SIGSYS]  = { NSIGSYS,  SIL_SYS },
+};
+
+static bool known_siginfo_layout(int sig, int si_code)
+{
+	if (si_code == SI_KERNEL)
+		return true;
+	else if ((si_code > SI_USER)) {
+		if (sig_specific_sicodes(sig)) {
+			if (si_code <= sig_sicodes[sig].limit)
+				return true;
+		}
+		else if (si_code <= NSIGPOLL)
+			return true;
+	}
+	else if (si_code >= SI_DETHREAD)
+		return true;
+	else if (si_code == SI_ASYNCNL)
+		return true;
+	return false;
+}
+
 enum siginfo_layout siginfo_layout(int sig, int si_code)
 {
 	enum siginfo_layout layout = SIL_KILL;
 	if ((si_code > SI_USER) && (si_code < SI_KERNEL)) {
-		static const struct {
-			unsigned char limit, layout;
-		} filter[] = {
-			[SIGILL]  = { NSIGILL,  SIL_FAULT },
-			[SIGFPE]  = { NSIGFPE,  SIL_FAULT },
-			[SIGSEGV] = { NSIGSEGV, SIL_FAULT },
-			[SIGBUS]  = { NSIGBUS,  SIL_FAULT },
-			[SIGTRAP] = { NSIGTRAP, SIL_FAULT },
-#if defined(SIGEMT)
-			[SIGEMT]  = { NSIGEMT,  SIL_FAULT },
-#endif
-			[SIGCHLD] = { NSIGCHLD, SIL_CHLD },
-			[SIGPOLL] = { NSIGPOLL, SIL_POLL },
-			[SIGSYS]  = { NSIGSYS,  SIL_SYS },
-		};
-		if ((sig < ARRAY_SIZE(filter)) && (si_code <= filter[sig].limit)) {
-			layout = filter[sig].layout;
+		if ((sig < ARRAY_SIZE(sig_sicodes)) &&
+		    (si_code <= sig_sicodes[sig].limit)) {
+			layout = sig_sicodes[sig].layout;
 			/* Handle the exceptions */
 			if ((sig == SIGBUS) &&
 			    (si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
@@ -2889,17 +2910,42 @@ enum siginfo_layout siginfo_layout(int sig, int si_code)
 	return layout;
 }
 
+static inline char __user *si_expansion(const siginfo_t __user *info)
+{
+	return ((char __user *)info) + sizeof(struct kernel_siginfo);
+}
+
 int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
 {
+	char __user *expansion = si_expansion(to);
 	if (copy_to_user(to, from , sizeof(struct kernel_siginfo)))
 		return -EFAULT;
+	if (clear_user(expansion, SI_EXPANSION_SIZE))
+		return -EFAULT;
 	return 0;
 }
 
 int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 {
-	if (copy_from_user(to, from, sizeof(struct siginfo)))
+	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
 		return -EFAULT;
+	if (unlikely(!known_siginfo_layout(to->si_signo, to->si_code))) {
+		char __user *expansion = si_expansion(from);
+		char buf[SI_EXPANSION_SIZE];
+		int i;
+		/*
+		 * An unknown si_code might need more than
+		 * sizeof(struct kernel_siginfo) bytes.  Verify all of the
+		 * extra bytes are 0.  This guarantees copy_siginfo_to_user
+		 * will return this data to userspace exactly.
+		 */
+		if (copy_from_user(&buf, expansion, SI_EXPANSION_SIZE))
+			return -EFAULT;
+		for (i = 0; i < SI_EXPANSION_SIZE; i++) {
+			if (buf[i] != 0)
+				return -E2BIG;
+		}
+	}
 	return 0;
 }
 
-- 
2.17.1

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig
  2018-09-25 17:19 ` [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig Eric W. Biederman
  2018-09-25 17:19   ` Eric W. Biederman
@ 2018-10-05  6:06   ` Andrei Vagin
  2018-10-05  6:06     ` Andrei Vagin
                       ` (3 more replies)
  1 sibling, 4 replies; 22+ messages in thread
From: Andrei Vagin @ 2018-10-05  6:06 UTC (permalink / raw)
  To: Eric W. Biederman
  Cc: linux-kernel, linux-api, linux-arch, Oleg Nesterov, Linus Torvalds

On Tue, Sep 25, 2018 at 07:19:02PM +0200, Eric W. Biederman wrote:
> The kernel needs to validate that the contents of struct siginfo make
> sense as siginfo is copied into the kernel, so that the proper union
> members can be put in the appropriate locations.  The field si_signo
> is a fundamental part of that validation.  As such changing the
> contents of si_signo after the validation make no sense and can result
> in nonsense values in the kernel.

Accoding to the man page, the user should not set si_signo, it has to be set
by kernel.

$ man 2 rt_sigqueueinfo

    The uinfo argument specifies the data to accompany  the  signal.   This
       argument  is  a  pointer to a structure of type siginfo_t, described in
       sigaction(2) (and defined  by  including  <sigaction.h>).   The  caller
       should set the following fields in this structure:

       si_code
              This  must  be  one of the SI_* codes in the Linux kernel source
              file include/asm-generic/siginfo.h, with  the  restriction  that
              the  code  must  be  negative (i.e., cannot be SI_USER, which is
              used by the kernel to indicate a signal  sent  by  kill(2))  and
              cannot  (since  Linux  2.6.39) be SI_TKILL (which is used by the
              kernel to indicate a signal sent using tgkill(2)).

       si_pid This should be set to a process ID, typically the process ID  of
              the sender.

       si_uid This  should  be set to a user ID, typically the real user ID of
              the sender.

       si_value
              This field contains the user data to accompany the signal.   For
              more information, see the description of the last (union sigval)
              argument of sigqueue(3).

       Internally, the kernel sets the si_signo field to the  value  specified
       in  sig,  so that the receiver of the signal can also obtain the signal
       number via that field.

> 
> As such simply fail if someone is silly enough to set si_signo out of
> sync with the signal number passed to sigqueueinfo.
> 
> I don't expect a problem as glibc's sigqueue implementation sets
> "si_signo = sig" and CRIU just returns to the kernel what the kernel
> gave to it.
> 
> If there is some application that calls sigqueueinfo directly that has
> a problem with this added sanity check we can revisit this when we see
> what kind of crazy that application is doing.


I already know two "applications" ;)

https://github.com/torvalds/linux/blob/master/tools/testing/selftests/ptrace/peeksiginfo.c
https://github.com/checkpoint-restore/criu/blob/master/test/zdtm/static/sigpending.c

Disclaimer: I'm the author of both of them.

> 
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> ---
>  kernel/signal.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/signal.c b/kernel/signal.c
> index 7b49c31d3fdb..e445b0a63faa 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -3306,7 +3306,8 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
>  	    (task_pid_vnr(current) != pid))
>  		return -EPERM;
>  
> -	info->si_signo = sig;
> +	if (info->si_signo != sig)
> +		return -EINVAL;
>  
>  	/* POSIX.1b doesn't mention process groups.  */
>  	return kill_proc_info(sig, info, pid);
> @@ -3354,7 +3355,8 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
>  	    (task_pid_vnr(current) != pid))
>  		return -EPERM;
>  
> -	info->si_signo = sig;
> +	if (info->si_signo != sig)
> +		return -EINVAL;
>  
>  	return do_send_specific(tgid, pid, sig, info);
>  }

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig
  2018-10-05  6:06   ` Andrei Vagin
@ 2018-10-05  6:06     ` Andrei Vagin
  2018-10-05  6:27     ` Eric W. Biederman
                       ` (2 subsequent siblings)
  3 siblings, 0 replies; 22+ messages in thread
From: Andrei Vagin @ 2018-10-05  6:06 UTC (permalink / raw)
  To: Eric W. Biederman
  Cc: linux-kernel, linux-api, linux-arch, Oleg Nesterov, Linus Torvalds

On Tue, Sep 25, 2018 at 07:19:02PM +0200, Eric W. Biederman wrote:
> The kernel needs to validate that the contents of struct siginfo make
> sense as siginfo is copied into the kernel, so that the proper union
> members can be put in the appropriate locations.  The field si_signo
> is a fundamental part of that validation.  As such changing the
> contents of si_signo after the validation make no sense and can result
> in nonsense values in the kernel.

Accoding to the man page, the user should not set si_signo, it has to be set
by kernel.

$ man 2 rt_sigqueueinfo

    The uinfo argument specifies the data to accompany  the  signal.   This
       argument  is  a  pointer to a structure of type siginfo_t, described in
       sigaction(2) (and defined  by  including  <sigaction.h>).   The  caller
       should set the following fields in this structure:

       si_code
              This  must  be  one of the SI_* codes in the Linux kernel source
              file include/asm-generic/siginfo.h, with  the  restriction  that
              the  code  must  be  negative (i.e., cannot be SI_USER, which is
              used by the kernel to indicate a signal  sent  by  kill(2))  and
              cannot  (since  Linux  2.6.39) be SI_TKILL (which is used by the
              kernel to indicate a signal sent using tgkill(2)).

       si_pid This should be set to a process ID, typically the process ID  of
              the sender.

       si_uid This  should  be set to a user ID, typically the real user ID of
              the sender.

       si_value
              This field contains the user data to accompany the signal.   For
              more information, see the description of the last (union sigval)
              argument of sigqueue(3).

       Internally, the kernel sets the si_signo field to the  value  specified
       in  sig,  so that the receiver of the signal can also obtain the signal
       number via that field.

> 
> As such simply fail if someone is silly enough to set si_signo out of
> sync with the signal number passed to sigqueueinfo.
> 
> I don't expect a problem as glibc's sigqueue implementation sets
> "si_signo = sig" and CRIU just returns to the kernel what the kernel
> gave to it.
> 
> If there is some application that calls sigqueueinfo directly that has
> a problem with this added sanity check we can revisit this when we see
> what kind of crazy that application is doing.


I already know two "applications" ;)

https://github.com/torvalds/linux/blob/master/tools/testing/selftests/ptrace/peeksiginfo.c
https://github.com/checkpoint-restore/criu/blob/master/test/zdtm/static/sigpending.c

Disclaimer: I'm the author of both of them.

> 
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
> ---
>  kernel/signal.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/signal.c b/kernel/signal.c
> index 7b49c31d3fdb..e445b0a63faa 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -3306,7 +3306,8 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
>  	    (task_pid_vnr(current) != pid))
>  		return -EPERM;
>  
> -	info->si_signo = sig;
> +	if (info->si_signo != sig)
> +		return -EINVAL;
>  
>  	/* POSIX.1b doesn't mention process groups.  */
>  	return kill_proc_info(sig, info, pid);
> @@ -3354,7 +3355,8 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
>  	    (task_pid_vnr(current) != pid))
>  		return -EPERM;
>  
> -	info->si_signo = sig;
> +	if (info->si_signo != sig)
> +		return -EINVAL;
>  
>  	return do_send_specific(tgid, pid, sig, info);
>  }

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig
  2018-10-05  6:06   ` Andrei Vagin
  2018-10-05  6:06     ` Andrei Vagin
@ 2018-10-05  6:27     ` Eric W. Biederman
  2018-10-05  6:27       ` Eric W. Biederman
  2018-10-05  6:50     ` Eric W. Biederman
  2018-10-05  7:10     ` [REVIEW][PATCH 7/6] signal: In sigqueueinfo prefer sig not si_signo Eric W. Biederman
  3 siblings, 1 reply; 22+ messages in thread
From: Eric W. Biederman @ 2018-10-05  6:27 UTC (permalink / raw)
  To: Andrei Vagin
  Cc: linux-kernel, linux-api, linux-arch, Oleg Nesterov, Linus Torvalds

Andrei Vagin <avagin@gmail.com> writes:

> On Tue, Sep 25, 2018 at 07:19:02PM +0200, Eric W. Biederman wrote:
>> The kernel needs to validate that the contents of struct siginfo make
>> sense as siginfo is copied into the kernel, so that the proper union
>> members can be put in the appropriate locations.  The field si_signo
>> is a fundamental part of that validation.  As such changing the
>> contents of si_signo after the validation make no sense and can result
>> in nonsense values in the kernel.
>
> Accoding to the man page, the user should not set si_signo, it has to be set
> by kernel.
>
> $ man 2 rt_sigqueueinfo
>
>     The uinfo argument specifies the data to accompany  the  signal.   This
>        argument  is  a  pointer to a structure of type siginfo_t, described in
>        sigaction(2) (and defined  by  including  <sigaction.h>).   The  caller
>        should set the following fields in this structure:
>
>        si_code
>               This  must  be  one of the SI_* codes in the Linux kernel source
>               file include/asm-generic/siginfo.h, with  the  restriction  that
>               the  code  must  be  negative (i.e., cannot be SI_USER, which is
>               used by the kernel to indicate a signal  sent  by  kill(2))  and
>               cannot  (since  Linux  2.6.39) be SI_TKILL (which is used by the
>               kernel to indicate a signal sent using tgkill(2)).
>
>        si_pid This should be set to a process ID, typically the process ID  of
>               the sender.
>
>        si_uid This  should  be set to a user ID, typically the real user ID of
>               the sender.
>
>        si_value
>               This field contains the user data to accompany the signal.   For
>               more information, see the description of the last (union sigval)
>               argument of sigqueue(3).
>
>        Internally, the kernel sets the si_signo field to the  value  specified
>        in  sig,  so that the receiver of the signal can also obtain the signal
>        number via that field.
>
>> 
>> As such simply fail if someone is silly enough to set si_signo out of
>> sync with the signal number passed to sigqueueinfo.
>> 
>> I don't expect a problem as glibc's sigqueue implementation sets
>> "si_signo = sig" and CRIU just returns to the kernel what the kernel
>> gave to it.
>> 
>> If there is some application that calls sigqueueinfo directly that has
>> a problem with this added sanity check we can revisit this when we see
>> what kind of crazy that application is doing.
>
>
> I already know two "applications" ;)
>
> https://github.com/torvalds/linux/blob/master/tools/testing/selftests/ptrace/peeksiginfo.c
> https://github.com/checkpoint-restore/criu/blob/master/test/zdtm/static/sigpending.c
>
> Disclaimer: I'm the author of both of them.

Fair enough.  Then this counts as a regression.  The setting in the
kernel happens in an awkward place and I will see if it can be moved
earlier.

Eric


>> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
>> ---
>>  kernel/signal.c | 6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>> 
>> diff --git a/kernel/signal.c b/kernel/signal.c
>> index 7b49c31d3fdb..e445b0a63faa 100644
>> --- a/kernel/signal.c
>> +++ b/kernel/signal.c
>> @@ -3306,7 +3306,8 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
>>  	    (task_pid_vnr(current) != pid))
>>  		return -EPERM;
>>  
>> -	info->si_signo = sig;
>> +	if (info->si_signo != sig)
>> +		return -EINVAL;
>>  
>>  	/* POSIX.1b doesn't mention process groups.  */
>>  	return kill_proc_info(sig, info, pid);
>> @@ -3354,7 +3355,8 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
>>  	    (task_pid_vnr(current) != pid))
>>  		return -EPERM;
>>  
>> -	info->si_signo = sig;
>> +	if (info->si_signo != sig)
>> +		return -EINVAL;
>>  
>>  	return do_send_specific(tgid, pid, sig, info);
>>  }

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig
  2018-10-05  6:27     ` Eric W. Biederman
@ 2018-10-05  6:27       ` Eric W. Biederman
  0 siblings, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-10-05  6:27 UTC (permalink / raw)
  To: Andrei Vagin
  Cc: linux-kernel, linux-api, linux-arch, Oleg Nesterov, Linus Torvalds

Andrei Vagin <avagin@gmail.com> writes:

> On Tue, Sep 25, 2018 at 07:19:02PM +0200, Eric W. Biederman wrote:
>> The kernel needs to validate that the contents of struct siginfo make
>> sense as siginfo is copied into the kernel, so that the proper union
>> members can be put in the appropriate locations.  The field si_signo
>> is a fundamental part of that validation.  As such changing the
>> contents of si_signo after the validation make no sense and can result
>> in nonsense values in the kernel.
>
> Accoding to the man page, the user should not set si_signo, it has to be set
> by kernel.
>
> $ man 2 rt_sigqueueinfo
>
>     The uinfo argument specifies the data to accompany  the  signal.   This
>        argument  is  a  pointer to a structure of type siginfo_t, described in
>        sigaction(2) (and defined  by  including  <sigaction.h>).   The  caller
>        should set the following fields in this structure:
>
>        si_code
>               This  must  be  one of the SI_* codes in the Linux kernel source
>               file include/asm-generic/siginfo.h, with  the  restriction  that
>               the  code  must  be  negative (i.e., cannot be SI_USER, which is
>               used by the kernel to indicate a signal  sent  by  kill(2))  and
>               cannot  (since  Linux  2.6.39) be SI_TKILL (which is used by the
>               kernel to indicate a signal sent using tgkill(2)).
>
>        si_pid This should be set to a process ID, typically the process ID  of
>               the sender.
>
>        si_uid This  should  be set to a user ID, typically the real user ID of
>               the sender.
>
>        si_value
>               This field contains the user data to accompany the signal.   For
>               more information, see the description of the last (union sigval)
>               argument of sigqueue(3).
>
>        Internally, the kernel sets the si_signo field to the  value  specified
>        in  sig,  so that the receiver of the signal can also obtain the signal
>        number via that field.
>
>> 
>> As such simply fail if someone is silly enough to set si_signo out of
>> sync with the signal number passed to sigqueueinfo.
>> 
>> I don't expect a problem as glibc's sigqueue implementation sets
>> "si_signo = sig" and CRIU just returns to the kernel what the kernel
>> gave to it.
>> 
>> If there is some application that calls sigqueueinfo directly that has
>> a problem with this added sanity check we can revisit this when we see
>> what kind of crazy that application is doing.
>
>
> I already know two "applications" ;)
>
> https://github.com/torvalds/linux/blob/master/tools/testing/selftests/ptrace/peeksiginfo.c
> https://github.com/checkpoint-restore/criu/blob/master/test/zdtm/static/sigpending.c
>
> Disclaimer: I'm the author of both of them.

Fair enough.  Then this counts as a regression.  The setting in the
kernel happens in an awkward place and I will see if it can be moved
earlier.

Eric


>> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
>> ---
>>  kernel/signal.c | 6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>> 
>> diff --git a/kernel/signal.c b/kernel/signal.c
>> index 7b49c31d3fdb..e445b0a63faa 100644
>> --- a/kernel/signal.c
>> +++ b/kernel/signal.c
>> @@ -3306,7 +3306,8 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
>>  	    (task_pid_vnr(current) != pid))
>>  		return -EPERM;
>>  
>> -	info->si_signo = sig;
>> +	if (info->si_signo != sig)
>> +		return -EINVAL;
>>  
>>  	/* POSIX.1b doesn't mention process groups.  */
>>  	return kill_proc_info(sig, info, pid);
>> @@ -3354,7 +3355,8 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
>>  	    (task_pid_vnr(current) != pid))
>>  		return -EPERM;
>>  
>> -	info->si_signo = sig;
>> +	if (info->si_signo != sig)
>> +		return -EINVAL;
>>  
>>  	return do_send_specific(tgid, pid, sig, info);
>>  }

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig
  2018-10-05  6:06   ` Andrei Vagin
  2018-10-05  6:06     ` Andrei Vagin
  2018-10-05  6:27     ` Eric W. Biederman
@ 2018-10-05  6:50     ` Eric W. Biederman
  2018-10-05  6:50       ` Eric W. Biederman
  2018-10-05  7:10     ` [REVIEW][PATCH 7/6] signal: In sigqueueinfo prefer sig not si_signo Eric W. Biederman
  3 siblings, 1 reply; 22+ messages in thread
From: Eric W. Biederman @ 2018-10-05  6:50 UTC (permalink / raw)
  To: Andrei Vagin
  Cc: linux-kernel, linux-api, linux-arch, Oleg Nesterov, Linus Torvalds

Andrei Vagin <avagin@gmail.com> writes:

> On Tue, Sep 25, 2018 at 07:19:02PM +0200, Eric W. Biederman wrote:
>> The kernel needs to validate that the contents of struct siginfo make
>> sense as siginfo is copied into the kernel, so that the proper union
>> members can be put in the appropriate locations.  The field si_signo
>> is a fundamental part of that validation.  As such changing the
>> contents of si_signo after the validation make no sense and can result
>> in nonsense values in the kernel.
>
> Accoding to the man page, the user should not set si_signo, it has to be set
> by kernel.

I wanted to say look at copy_siginfo_from_user32 it uses si_signo and it
has always done so.  But before I got to fixing copy_siginfo_from_user32
only looked at si_code.  This is one of the areas where we deliberately
slightly changed the KABI.  To start looking an signo instead of magic
kernel internal si_code values.

So yes.  Looking at si_signo instead of the passed in signo appears to
be a regression all of the way around (except for ptrace) where that
value is not present.  So I will see if I can figure out how to refactor
the code to accomplish that.

I am travelling for the next couple of days so I won't be able to get to
this for a bit.

I am thinking I will need two version of copy_siginfo_from user now.
One for ptrace and one for rt_sgiqueueinfo.  Sigh.

> $ man 2 rt_sigqueueinfo
>
>     The uinfo argument specifies the data to accompany  the  signal.   This
>        argument  is  a  pointer to a structure of type siginfo_t, described in
>        sigaction(2) (and defined  by  including  <sigaction.h>).   The  caller
>        should set the following fields in this structure:
>
>        si_code
>               This  must  be  one of the SI_* codes in the Linux kernel source
>               file include/asm-generic/siginfo.h, with  the  restriction  that
>               the  code  must  be  negative (i.e., cannot be SI_USER, which is
>               used by the kernel to indicate a signal  sent  by  kill(2))  and
>               cannot  (since  Linux  2.6.39) be SI_TKILL (which is used by the
>               kernel to indicate a signal sent using tgkill(2)).
>
>        si_pid This should be set to a process ID, typically the process ID  of
>               the sender.
>
>        si_uid This  should  be set to a user ID, typically the real user ID of
>               the sender.
>
>        si_value
>               This field contains the user data to accompany the signal.   For
>               more information, see the description of the last (union sigval)
>               argument of sigqueue(3).
>
>        Internally, the kernel sets the si_signo field to the  value  specified
>        in  sig,  so that the receiver of the signal can also obtain the signal
>        number via that field.
>
>> 
>> As such simply fail if someone is silly enough to set si_signo out of
>> sync with the signal number passed to sigqueueinfo.
>> 
>> I don't expect a problem as glibc's sigqueue implementation sets
>> "si_signo = sig" and CRIU just returns to the kernel what the kernel
>> gave to it.
>> 
>> If there is some application that calls sigqueueinfo directly that has
>> a problem with this added sanity check we can revisit this when we see
>> what kind of crazy that application is doing.
>
>
> I already know two "applications" ;)
>
> https://github.com/torvalds/linux/blob/master/tools/testing/selftests/ptrace/peeksiginfo.c
> https://github.com/checkpoint-restore/criu/blob/master/test/zdtm/static/sigpending.c
>
> Disclaimer: I'm the author of both of them.
>
>> 
>> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
>> ---
>>  kernel/signal.c | 6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>> 
>> diff --git a/kernel/signal.c b/kernel/signal.c
>> index 7b49c31d3fdb..e445b0a63faa 100644
>> --- a/kernel/signal.c
>> +++ b/kernel/signal.c
>> @@ -3306,7 +3306,8 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
>>  	    (task_pid_vnr(current) != pid))
>>  		return -EPERM;
>>  
>> -	info->si_signo = sig;
>> +	if (info->si_signo != sig)
>> +		return -EINVAL;
>>  
>>  	/* POSIX.1b doesn't mention process groups.  */
>>  	return kill_proc_info(sig, info, pid);
>> @@ -3354,7 +3355,8 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
>>  	    (task_pid_vnr(current) != pid))
>>  		return -EPERM;
>>  
>> -	info->si_signo = sig;
>> +	if (info->si_signo != sig)
>> +		return -EINVAL;
>>  
>>  	return do_send_specific(tgid, pid, sig, info);
>>  }

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig
  2018-10-05  6:50     ` Eric W. Biederman
@ 2018-10-05  6:50       ` Eric W. Biederman
  0 siblings, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-10-05  6:50 UTC (permalink / raw)
  To: Andrei Vagin
  Cc: linux-kernel, linux-api, linux-arch, Oleg Nesterov, Linus Torvalds

Andrei Vagin <avagin@gmail.com> writes:

> On Tue, Sep 25, 2018 at 07:19:02PM +0200, Eric W. Biederman wrote:
>> The kernel needs to validate that the contents of struct siginfo make
>> sense as siginfo is copied into the kernel, so that the proper union
>> members can be put in the appropriate locations.  The field si_signo
>> is a fundamental part of that validation.  As such changing the
>> contents of si_signo after the validation make no sense and can result
>> in nonsense values in the kernel.
>
> Accoding to the man page, the user should not set si_signo, it has to be set
> by kernel.

I wanted to say look at copy_siginfo_from_user32 it uses si_signo and it
has always done so.  But before I got to fixing copy_siginfo_from_user32
only looked at si_code.  This is one of the areas where we deliberately
slightly changed the KABI.  To start looking an signo instead of magic
kernel internal si_code values.

So yes.  Looking at si_signo instead of the passed in signo appears to
be a regression all of the way around (except for ptrace) where that
value is not present.  So I will see if I can figure out how to refactor
the code to accomplish that.

I am travelling for the next couple of days so I won't be able to get to
this for a bit.

I am thinking I will need two version of copy_siginfo_from user now.
One for ptrace and one for rt_sgiqueueinfo.  Sigh.

> $ man 2 rt_sigqueueinfo
>
>     The uinfo argument specifies the data to accompany  the  signal.   This
>        argument  is  a  pointer to a structure of type siginfo_t, described in
>        sigaction(2) (and defined  by  including  <sigaction.h>).   The  caller
>        should set the following fields in this structure:
>
>        si_code
>               This  must  be  one of the SI_* codes in the Linux kernel source
>               file include/asm-generic/siginfo.h, with  the  restriction  that
>               the  code  must  be  negative (i.e., cannot be SI_USER, which is
>               used by the kernel to indicate a signal  sent  by  kill(2))  and
>               cannot  (since  Linux  2.6.39) be SI_TKILL (which is used by the
>               kernel to indicate a signal sent using tgkill(2)).
>
>        si_pid This should be set to a process ID, typically the process ID  of
>               the sender.
>
>        si_uid This  should  be set to a user ID, typically the real user ID of
>               the sender.
>
>        si_value
>               This field contains the user data to accompany the signal.   For
>               more information, see the description of the last (union sigval)
>               argument of sigqueue(3).
>
>        Internally, the kernel sets the si_signo field to the  value  specified
>        in  sig,  so that the receiver of the signal can also obtain the signal
>        number via that field.
>
>> 
>> As such simply fail if someone is silly enough to set si_signo out of
>> sync with the signal number passed to sigqueueinfo.
>> 
>> I don't expect a problem as glibc's sigqueue implementation sets
>> "si_signo = sig" and CRIU just returns to the kernel what the kernel
>> gave to it.
>> 
>> If there is some application that calls sigqueueinfo directly that has
>> a problem with this added sanity check we can revisit this when we see
>> what kind of crazy that application is doing.
>
>
> I already know two "applications" ;)
>
> https://github.com/torvalds/linux/blob/master/tools/testing/selftests/ptrace/peeksiginfo.c
> https://github.com/checkpoint-restore/criu/blob/master/test/zdtm/static/sigpending.c
>
> Disclaimer: I'm the author of both of them.
>
>> 
>> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
>> ---
>>  kernel/signal.c | 6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>> 
>> diff --git a/kernel/signal.c b/kernel/signal.c
>> index 7b49c31d3fdb..e445b0a63faa 100644
>> --- a/kernel/signal.c
>> +++ b/kernel/signal.c
>> @@ -3306,7 +3306,8 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, siginfo_t *info)
>>  	    (task_pid_vnr(current) != pid))
>>  		return -EPERM;
>>  
>> -	info->si_signo = sig;
>> +	if (info->si_signo != sig)
>> +		return -EINVAL;
>>  
>>  	/* POSIX.1b doesn't mention process groups.  */
>>  	return kill_proc_info(sig, info, pid);
>> @@ -3354,7 +3355,8 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, siginfo_t *info)
>>  	    (task_pid_vnr(current) != pid))
>>  		return -EPERM;
>>  
>> -	info->si_signo = sig;
>> +	if (info->si_signo != sig)
>> +		return -EINVAL;
>>  
>>  	return do_send_specific(tgid, pid, sig, info);
>>  }

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 7/6] signal: In sigqueueinfo prefer sig not si_signo
  2018-10-05  6:06   ` Andrei Vagin
                       ` (2 preceding siblings ...)
  2018-10-05  6:50     ` Eric W. Biederman
@ 2018-10-05  7:10     ` Eric W. Biederman
  2018-10-05  7:10       ` Eric W. Biederman
  3 siblings, 1 reply; 22+ messages in thread
From: Eric W. Biederman @ 2018-10-05  7:10 UTC (permalink / raw)
  To: Andrei Vagin
  Cc: linux-kernel, linux-api, linux-arch, Oleg Nesterov, Linus Torvalds


Andrei Vagin <avagin@gmail.com> reported:

> Accoding to the man page, the user should not set si_signo, it has to be set
> by kernel.
>
> $ man 2 rt_sigqueueinfo
>
>     The uinfo argument specifies the data to accompany  the  signal.   This
>        argument  is  a  pointer to a structure of type siginfo_t, described in
>        sigaction(2) (and defined  by  including  <sigaction.h>).   The  caller
>        should set the following fields in this structure:
>
>        si_code
>               This  must  be  one of the SI_* codes in the Linux kernel source
>               file include/asm-generic/siginfo.h, with  the  restriction  that
>               the  code  must  be  negative (i.e., cannot be SI_USER, which is
>               used by the kernel to indicate a signal  sent  by  kill(2))  and
>               cannot  (since  Linux  2.6.39) be SI_TKILL (which is used by the
>               kernel to indicate a signal sent using tgkill(2)).
>
>        si_pid This should be set to a process ID, typically the process ID  of
>               the sender.
>
>        si_uid This  should  be set to a user ID, typically the real user ID of
>               the sender.
>
>        si_value
>               This field contains the user data to accompany the signal.   For
>               more information, see the description of the last (union sigval)
>               argument of sigqueue(3).
>
>        Internally, the kernel sets the si_signo field to the  value  specified
>        in  sig,  so that the receiver of the signal can also obtain the signal
>        number via that field.
>
> On Tue, Sep 25, 2018 at 07:19:02PM +0200, Eric W. Biederman wrote:
>>
>> If there is some application that calls sigqueueinfo directly that has
>> a problem with this added sanity check we can revisit this when we see
>> what kind of crazy that application is doing.
>
>
> I already know two "applications" ;)
>
> https://github.com/torvalds/linux/blob/master/tools/testing/selftests/ptrace/peeksiginfo.c
> https://github.com/checkpoint-restore/criu/blob/master/test/zdtm/static/sigpending.c
>
> Disclaimer: I'm the author of both of them.

Looking at the kernel code the historical behavior has alwasy been to prefer
the signal number passed in by the kernel.

So sigh.  Implmenet __copy_siginfo_from_user and __copy_siginfo_from_user32 to
take that signal number and prefer it.  The user of ptrace will still
use copy_siginfo_from_user and copy_siginfo_from_user32 as they do not and
never have had a signal number there.

Luckily this change has never made it farther than linux-next.

Fixes: e75dc036c445 ("signal: Fail sigqueueinfo if si_signo != sig")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---

Andrei can you verify this fixes your programs?
Thank you very much,
Eric


 kernel/signal.c | 141 ++++++++++++++++++++++++++++--------------------
 1 file changed, 84 insertions(+), 57 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 1c2dd117fee0..2bffc5a50183 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2925,11 +2925,10 @@ int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
 	return 0;
 }
 
-int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
+static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
+				       const siginfo_t __user *from)
 {
-	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
-		return -EFAULT;
-	if (unlikely(!known_siginfo_layout(to->si_signo, to->si_code))) {
+	if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
 		char __user *expansion = si_expansion(from);
 		char buf[SI_EXPANSION_SIZE];
 		int i;
@@ -2949,6 +2948,22 @@ int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 	return 0;
 }
 
+static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
+				    const siginfo_t __user *from)
+{
+	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
+		return -EFAULT;
+	to->si_signo = signo;
+	return post_copy_siginfo_from_user(to, from);
+}
+
+int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
+{
+	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
+		return -EFAULT;
+	return post_copy_siginfo_from_user(to, from);
+}
+
 #ifdef CONFIG_COMPAT
 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
 			   const struct kernel_siginfo *from)
@@ -3041,88 +3056,106 @@ int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
 	return 0;
 }
 
-int copy_siginfo_from_user32(struct kernel_siginfo *to,
-			     const struct compat_siginfo __user *ufrom)
+static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
+					 const struct compat_siginfo *from)
 {
-	struct compat_siginfo from;
-
-	if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
-		return -EFAULT;
-
 	clear_siginfo(to);
-	to->si_signo = from.si_signo;
-	to->si_errno = from.si_errno;
-	to->si_code  = from.si_code;
-	switch(siginfo_layout(from.si_signo, from.si_code)) {
+	to->si_signo = from->si_signo;
+	to->si_errno = from->si_errno;
+	to->si_code  = from->si_code;
+	switch(siginfo_layout(from->si_signo, from->si_code)) {
 	case SIL_KILL:
-		to->si_pid = from.si_pid;
-		to->si_uid = from.si_uid;
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
 		break;
 	case SIL_TIMER:
-		to->si_tid     = from.si_tid;
-		to->si_overrun = from.si_overrun;
-		to->si_int     = from.si_int;
+		to->si_tid     = from->si_tid;
+		to->si_overrun = from->si_overrun;
+		to->si_int     = from->si_int;
 		break;
 	case SIL_POLL:
-		to->si_band = from.si_band;
-		to->si_fd   = from.si_fd;
+		to->si_band = from->si_band;
+		to->si_fd   = from->si_fd;
 		break;
 	case SIL_FAULT:
-		to->si_addr = compat_ptr(from.si_addr);
+		to->si_addr = compat_ptr(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from.si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
 		break;
 	case SIL_FAULT_MCEERR:
-		to->si_addr = compat_ptr(from.si_addr);
+		to->si_addr = compat_ptr(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from.si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		to->si_addr_lsb = from.si_addr_lsb;
+		to->si_addr_lsb = from->si_addr_lsb;
 		break;
 	case SIL_FAULT_BNDERR:
-		to->si_addr = compat_ptr(from.si_addr);
+		to->si_addr = compat_ptr(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from.si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		to->si_lower = compat_ptr(from.si_lower);
-		to->si_upper = compat_ptr(from.si_upper);
+		to->si_lower = compat_ptr(from->si_lower);
+		to->si_upper = compat_ptr(from->si_upper);
 		break;
 	case SIL_FAULT_PKUERR:
-		to->si_addr = compat_ptr(from.si_addr);
+		to->si_addr = compat_ptr(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from.si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		to->si_pkey = from.si_pkey;
+		to->si_pkey = from->si_pkey;
 		break;
 	case SIL_CHLD:
-		to->si_pid    = from.si_pid;
-		to->si_uid    = from.si_uid;
-		to->si_status = from.si_status;
+		to->si_pid    = from->si_pid;
+		to->si_uid    = from->si_uid;
+		to->si_status = from->si_status;
 #ifdef CONFIG_X86_X32_ABI
 		if (in_x32_syscall()) {
-			to->si_utime = from._sifields._sigchld_x32._utime;
-			to->si_stime = from._sifields._sigchld_x32._stime;
+			to->si_utime = from->_sifields._sigchld_x32._utime;
+			to->si_stime = from->_sifields._sigchld_x32._stime;
 		} else
 #endif
 		{
-			to->si_utime = from.si_utime;
-			to->si_stime = from.si_stime;
+			to->si_utime = from->si_utime;
+			to->si_stime = from->si_stime;
 		}
 		break;
 	case SIL_RT:
-		to->si_pid = from.si_pid;
-		to->si_uid = from.si_uid;
-		to->si_int = from.si_int;
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		to->si_int = from->si_int;
 		break;
 	case SIL_SYS:
-		to->si_call_addr = compat_ptr(from.si_call_addr);
-		to->si_syscall   = from.si_syscall;
-		to->si_arch      = from.si_arch;
+		to->si_call_addr = compat_ptr(from->si_call_addr);
+		to->si_syscall   = from->si_syscall;
+		to->si_arch      = from->si_arch;
 		break;
 	}
 	return 0;
 }
+
+static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
+				      const struct compat_siginfo __user *ufrom)
+{
+	struct compat_siginfo from;
+
+	if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
+		return -EFAULT;
+
+	from.si_signo = signo;
+	return post_copy_siginfo_from_user32(to, &from);
+}
+
+int copy_siginfo_from_user32(struct kernel_siginfo *to,
+			     const struct compat_siginfo __user *ufrom)
+{
+	struct compat_siginfo from;
+
+	if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
+		return -EFAULT;
+
+	return post_copy_siginfo_from_user32(to, &from);
+}
 #endif /* CONFIG_COMPAT */
 
 /**
@@ -3359,9 +3392,6 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
 	    (task_pid_vnr(current) != pid))
 		return -EPERM;
 
-	if (info->si_signo != sig)
-		return -EINVAL;
-
 	/* POSIX.1b doesn't mention process groups.  */
 	return kill_proc_info(sig, info, pid);
 }
@@ -3376,7 +3406,7 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
 	kernel_siginfo_t info;
-	int ret = copy_siginfo_from_user(&info, uinfo);
+	int ret = __copy_siginfo_from_user(sig, &info, uinfo);
 	if (unlikely(ret))
 		return ret;
 	return do_rt_sigqueueinfo(pid, sig, &info);
@@ -3389,7 +3419,7 @@ COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
 			struct compat_siginfo __user *, uinfo)
 {
 	kernel_siginfo_t info;
-	int ret = copy_siginfo_from_user32(&info, uinfo);
+	int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
 	if (unlikely(ret))
 		return ret;
 	return do_rt_sigqueueinfo(pid, sig, &info);
@@ -3409,9 +3439,6 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t
 	    (task_pid_vnr(current) != pid))
 		return -EPERM;
 
-	if (info->si_signo != sig)
-		return -EINVAL;
-
 	return do_send_specific(tgid, pid, sig, info);
 }
 
@@ -3419,7 +3446,7 @@ SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
 	kernel_siginfo_t info;
-	int ret = copy_siginfo_from_user(&info, uinfo);
+	int ret = __copy_siginfo_from_user(sig, &info, uinfo);
 	if (unlikely(ret))
 		return ret;
 	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
@@ -3433,7 +3460,7 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
 			struct compat_siginfo __user *, uinfo)
 {
 	kernel_siginfo_t info;
-	int ret = copy_siginfo_from_user32(&info, uinfo);
+	int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
 	if (unlikely(ret))
 		return ret;
 	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);

^ permalink raw reply	[flat|nested] 22+ messages in thread

* [REVIEW][PATCH 7/6] signal: In sigqueueinfo prefer sig not si_signo
  2018-10-05  7:10     ` [REVIEW][PATCH 7/6] signal: In sigqueueinfo prefer sig not si_signo Eric W. Biederman
@ 2018-10-05  7:10       ` Eric W. Biederman
  0 siblings, 0 replies; 22+ messages in thread
From: Eric W. Biederman @ 2018-10-05  7:10 UTC (permalink / raw)
  To: Andrei Vagin
  Cc: linux-kernel, linux-api, linux-arch, Oleg Nesterov, Linus Torvalds


Andrei Vagin <avagin@gmail.com> reported:

> Accoding to the man page, the user should not set si_signo, it has to be set
> by kernel.
>
> $ man 2 rt_sigqueueinfo
>
>     The uinfo argument specifies the data to accompany  the  signal.   This
>        argument  is  a  pointer to a structure of type siginfo_t, described in
>        sigaction(2) (and defined  by  including  <sigaction.h>).   The  caller
>        should set the following fields in this structure:
>
>        si_code
>               This  must  be  one of the SI_* codes in the Linux kernel source
>               file include/asm-generic/siginfo.h, with  the  restriction  that
>               the  code  must  be  negative (i.e., cannot be SI_USER, which is
>               used by the kernel to indicate a signal  sent  by  kill(2))  and
>               cannot  (since  Linux  2.6.39) be SI_TKILL (which is used by the
>               kernel to indicate a signal sent using tgkill(2)).
>
>        si_pid This should be set to a process ID, typically the process ID  of
>               the sender.
>
>        si_uid This  should  be set to a user ID, typically the real user ID of
>               the sender.
>
>        si_value
>               This field contains the user data to accompany the signal.   For
>               more information, see the description of the last (union sigval)
>               argument of sigqueue(3).
>
>        Internally, the kernel sets the si_signo field to the  value  specified
>        in  sig,  so that the receiver of the signal can also obtain the signal
>        number via that field.
>
> On Tue, Sep 25, 2018 at 07:19:02PM +0200, Eric W. Biederman wrote:
>>
>> If there is some application that calls sigqueueinfo directly that has
>> a problem with this added sanity check we can revisit this when we see
>> what kind of crazy that application is doing.
>
>
> I already know two "applications" ;)
>
> https://github.com/torvalds/linux/blob/master/tools/testing/selftests/ptrace/peeksiginfo.c
> https://github.com/checkpoint-restore/criu/blob/master/test/zdtm/static/sigpending.c
>
> Disclaimer: I'm the author of both of them.

Looking at the kernel code the historical behavior has alwasy been to prefer
the signal number passed in by the kernel.

So sigh.  Implmenet __copy_siginfo_from_user and __copy_siginfo_from_user32 to
take that signal number and prefer it.  The user of ptrace will still
use copy_siginfo_from_user and copy_siginfo_from_user32 as they do not and
never have had a signal number there.

Luckily this change has never made it farther than linux-next.

Fixes: e75dc036c445 ("signal: Fail sigqueueinfo if si_signo != sig")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---

Andrei can you verify this fixes your programs?
Thank you very much,
Eric


 kernel/signal.c | 141 ++++++++++++++++++++++++++++--------------------
 1 file changed, 84 insertions(+), 57 deletions(-)

diff --git a/kernel/signal.c b/kernel/signal.c
index 1c2dd117fee0..2bffc5a50183 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2925,11 +2925,10 @@ int copy_siginfo_to_user(siginfo_t __user *to, const kernel_siginfo_t *from)
 	return 0;
 }
 
-int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
+static int post_copy_siginfo_from_user(kernel_siginfo_t *info,
+				       const siginfo_t __user *from)
 {
-	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
-		return -EFAULT;
-	if (unlikely(!known_siginfo_layout(to->si_signo, to->si_code))) {
+	if (unlikely(!known_siginfo_layout(info->si_signo, info->si_code))) {
 		char __user *expansion = si_expansion(from);
 		char buf[SI_EXPANSION_SIZE];
 		int i;
@@ -2949,6 +2948,22 @@ int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 	return 0;
 }
 
+static int __copy_siginfo_from_user(int signo, kernel_siginfo_t *to,
+				    const siginfo_t __user *from)
+{
+	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
+		return -EFAULT;
+	to->si_signo = signo;
+	return post_copy_siginfo_from_user(to, from);
+}
+
+int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
+{
+	if (copy_from_user(to, from, sizeof(struct kernel_siginfo)))
+		return -EFAULT;
+	return post_copy_siginfo_from_user(to, from);
+}
+
 #ifdef CONFIG_COMPAT
 int copy_siginfo_to_user32(struct compat_siginfo __user *to,
 			   const struct kernel_siginfo *from)
@@ -3041,88 +3056,106 @@ int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
 	return 0;
 }
 
-int copy_siginfo_from_user32(struct kernel_siginfo *to,
-			     const struct compat_siginfo __user *ufrom)
+static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
+					 const struct compat_siginfo *from)
 {
-	struct compat_siginfo from;
-
-	if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
-		return -EFAULT;
-
 	clear_siginfo(to);
-	to->si_signo = from.si_signo;
-	to->si_errno = from.si_errno;
-	to->si_code  = from.si_code;
-	switch(siginfo_layout(from.si_signo, from.si_code)) {
+	to->si_signo = from->si_signo;
+	to->si_errno = from->si_errno;
+	to->si_code  = from->si_code;
+	switch(siginfo_layout(from->si_signo, from->si_code)) {
 	case SIL_KILL:
-		to->si_pid = from.si_pid;
-		to->si_uid = from.si_uid;
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
 		break;
 	case SIL_TIMER:
-		to->si_tid     = from.si_tid;
-		to->si_overrun = from.si_overrun;
-		to->si_int     = from.si_int;
+		to->si_tid     = from->si_tid;
+		to->si_overrun = from->si_overrun;
+		to->si_int     = from->si_int;
 		break;
 	case SIL_POLL:
-		to->si_band = from.si_band;
-		to->si_fd   = from.si_fd;
+		to->si_band = from->si_band;
+		to->si_fd   = from->si_fd;
 		break;
 	case SIL_FAULT:
-		to->si_addr = compat_ptr(from.si_addr);
+		to->si_addr = compat_ptr(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from.si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
 		break;
 	case SIL_FAULT_MCEERR:
-		to->si_addr = compat_ptr(from.si_addr);
+		to->si_addr = compat_ptr(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from.si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		to->si_addr_lsb = from.si_addr_lsb;
+		to->si_addr_lsb = from->si_addr_lsb;
 		break;
 	case SIL_FAULT_BNDERR:
-		to->si_addr = compat_ptr(from.si_addr);
+		to->si_addr = compat_ptr(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from.si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		to->si_lower = compat_ptr(from.si_lower);
-		to->si_upper = compat_ptr(from.si_upper);
+		to->si_lower = compat_ptr(from->si_lower);
+		to->si_upper = compat_ptr(from->si_upper);
 		break;
 	case SIL_FAULT_PKUERR:
-		to->si_addr = compat_ptr(from.si_addr);
+		to->si_addr = compat_ptr(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		to->si_trapno = from.si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		to->si_pkey = from.si_pkey;
+		to->si_pkey = from->si_pkey;
 		break;
 	case SIL_CHLD:
-		to->si_pid    = from.si_pid;
-		to->si_uid    = from.si_uid;
-		to->si_status = from.si_status;
+		to->si_pid    = from->si_pid;
+		to->si_uid    = from->si_uid;
+		to->si_status = from->si_status;
 #ifdef CONFIG_X86_X32_ABI
 		if (in_x32_syscall()) {
-			to->si_utime = from._sifields._sigchld_x32._utime;
-			to->si_stime = from._sifields._sigchld_x32._stime;
+			to->si_utime = from->_sifields._sigchld_x32._utime;
+			to->si_stime = from->_sifields._sigchld_x32._stime;
 		} else
 #endif
 		{
-			to->si_utime = from.si_utime;
-			to->si_stime = from.si_stime;
+			to->si_utime = from->si_utime;
+			to->si_stime = from->si_stime;
 		}
 		break;
 	case SIL_RT:
-		to->si_pid = from.si_pid;
-		to->si_uid = from.si_uid;
-		to->si_int = from.si_int;
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
+		to->si_int = from->si_int;
 		break;
 	case SIL_SYS:
-		to->si_call_addr = compat_ptr(from.si_call_addr);
-		to->si_syscall   = from.si_syscall;
-		to->si_arch      = from.si_arch;
+		to->si_call_addr = compat_ptr(from->si_call_addr);
+		to->si_syscall   = from->si_syscall;
+		to->si_arch      = from->si_arch;
 		break;
 	}
 	return 0;
 }
+
+static int __copy_siginfo_from_user32(int signo, struct kernel_siginfo *to,
+				      const struct compat_siginfo __user *ufrom)
+{
+	struct compat_siginfo from;
+
+	if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
+		return -EFAULT;
+
+	from.si_signo = signo;
+	return post_copy_siginfo_from_user32(to, &from);
+}
+
+int copy_siginfo_from_user32(struct kernel_siginfo *to,
+			     const struct compat_siginfo __user *ufrom)
+{
+	struct compat_siginfo from;
+
+	if (copy_from_user(&from, ufrom, sizeof(struct compat_siginfo)))
+		return -EFAULT;
+
+	return post_copy_siginfo_from_user32(to, &from);
+}
 #endif /* CONFIG_COMPAT */
 
 /**
@@ -3359,9 +3392,6 @@ static int do_rt_sigqueueinfo(pid_t pid, int sig, kernel_siginfo_t *info)
 	    (task_pid_vnr(current) != pid))
 		return -EPERM;
 
-	if (info->si_signo != sig)
-		return -EINVAL;
-
 	/* POSIX.1b doesn't mention process groups.  */
 	return kill_proc_info(sig, info, pid);
 }
@@ -3376,7 +3406,7 @@ SYSCALL_DEFINE3(rt_sigqueueinfo, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
 	kernel_siginfo_t info;
-	int ret = copy_siginfo_from_user(&info, uinfo);
+	int ret = __copy_siginfo_from_user(sig, &info, uinfo);
 	if (unlikely(ret))
 		return ret;
 	return do_rt_sigqueueinfo(pid, sig, &info);
@@ -3389,7 +3419,7 @@ COMPAT_SYSCALL_DEFINE3(rt_sigqueueinfo,
 			struct compat_siginfo __user *, uinfo)
 {
 	kernel_siginfo_t info;
-	int ret = copy_siginfo_from_user32(&info, uinfo);
+	int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
 	if (unlikely(ret))
 		return ret;
 	return do_rt_sigqueueinfo(pid, sig, &info);
@@ -3409,9 +3439,6 @@ static int do_rt_tgsigqueueinfo(pid_t tgid, pid_t pid, int sig, kernel_siginfo_t
 	    (task_pid_vnr(current) != pid))
 		return -EPERM;
 
-	if (info->si_signo != sig)
-		return -EINVAL;
-
 	return do_send_specific(tgid, pid, sig, info);
 }
 
@@ -3419,7 +3446,7 @@ SYSCALL_DEFINE4(rt_tgsigqueueinfo, pid_t, tgid, pid_t, pid, int, sig,
 		siginfo_t __user *, uinfo)
 {
 	kernel_siginfo_t info;
-	int ret = copy_siginfo_from_user(&info, uinfo);
+	int ret = __copy_siginfo_from_user(sig, &info, uinfo);
 	if (unlikely(ret))
 		return ret;
 	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);
@@ -3433,7 +3460,7 @@ COMPAT_SYSCALL_DEFINE4(rt_tgsigqueueinfo,
 			struct compat_siginfo __user *, uinfo)
 {
 	kernel_siginfo_t info;
-	int ret = copy_siginfo_from_user32(&info, uinfo);
+	int ret = __copy_siginfo_from_user32(sig, &info, uinfo);
 	if (unlikely(ret))
 		return ret;
 	return do_rt_tgsigqueueinfo(tgid, pid, sig, &info);

^ permalink raw reply	[flat|nested] 22+ messages in thread

end of thread, other threads:[~2018-10-05 14:08 UTC | newest]

Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-09-25 17:16 [REVIEW][PATCH 0/6] signal: Shrinking the kernel's siginfo structure Eric W. Biederman
2018-09-25 17:16 ` Eric W. Biederman
2018-09-25 17:19 ` [REVIEW][PATCH 1/6] signal/sparc: Move EMT_TAGOVF into the generic siginfo.h Eric W. Biederman
2018-09-25 17:19   ` Eric W. Biederman
2018-09-25 17:19 ` [REVIEW][PATCH 2/6] signal: Fail sigqueueinfo if si_signo != sig Eric W. Biederman
2018-09-25 17:19   ` Eric W. Biederman
2018-10-05  6:06   ` Andrei Vagin
2018-10-05  6:06     ` Andrei Vagin
2018-10-05  6:27     ` Eric W. Biederman
2018-10-05  6:27       ` Eric W. Biederman
2018-10-05  6:50     ` Eric W. Biederman
2018-10-05  6:50       ` Eric W. Biederman
2018-10-05  7:10     ` [REVIEW][PATCH 7/6] signal: In sigqueueinfo prefer sig not si_signo Eric W. Biederman
2018-10-05  7:10       ` Eric W. Biederman
2018-09-25 17:19 ` [REVIEW][PATCH 3/6] signal: Remove the need for __ARCH_SI_PREABLE_SIZE and SI_PAD_SIZE Eric W. Biederman
2018-09-25 17:19   ` Eric W. Biederman
2018-09-25 17:19 ` [REVIEW][PATCH 4/6] signal: Introduce copy_siginfo_from_user and use it's return value Eric W. Biederman
2018-09-25 17:19   ` Eric W. Biederman
2018-09-25 17:19 ` [REVIEW][PATCH 5/6] signal: Distinguish between kernel_siginfo and siginfo Eric W. Biederman
2018-09-25 17:19   ` Eric W. Biederman
2018-09-25 17:19 ` [REVIEW][PATCH 6/6] signal: Use a smaller struct siginfo in the kernel Eric W. Biederman
2018-09-25 17:19   ` Eric W. Biederman

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).