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From: ebiederm@xmission.com (Eric W. Biederman)
To: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Jeremy Kerr <jk@ozlabs.org>, Arnd Bergmann <arnd@arndb.de>,
	linuxppc-dev@lists.ozlabs.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, x86@kernel.org
Subject: [PATCH 1/2] signal: Factor copy_siginfo_to_external32 from copy_siginfo_to_user32
Date: Fri, 17 Apr 2020 16:09:22 -0500	[thread overview]
Message-ID: <87k12dakfx.fsf_-_@x220.int.ebiederm.org> (raw)
In-Reply-To: <87pnc5akhk.fsf@x220.int.ebiederm.org> (Eric W. Biederman's message of "Fri, 17 Apr 2020 16:08:23 -0500")


To remove the use of set_fs in the coredump code there needs to be a
way to convert a kernel siginfo to a userspace compat siginfo.

Call that function copy_siginfo_to_compat and factor it out of
copy_siginfo_to_user32.

The existence of x32 complicates this code.  On x32 SIGCHLD uses 64bit
times for utime and stime.  As only SIGCHLD is affected and SIGCHLD
never causes a coredump I have avoided handling that case.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 include/linux/compat.h |   1 +
 kernel/signal.c        | 108 +++++++++++++++++++++++------------------
 2 files changed, 63 insertions(+), 46 deletions(-)

diff --git a/include/linux/compat.h b/include/linux/compat.h
index 0480ba4db592..4962b254e550 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -402,6 +402,7 @@ 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);
+void copy_siginfo_to_external32(struct compat_siginfo *to, const struct kernel_siginfo *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,
diff --git a/kernel/signal.c b/kernel/signal.c
index e58a6c619824..578f196898cb 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3235,90 +3235,106 @@ int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 }
 
 #ifdef CONFIG_COMPAT
-int copy_siginfo_to_user32(struct compat_siginfo __user *to,
-			   const struct kernel_siginfo *from)
-#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
+void copy_siginfo_to_external32(struct compat_siginfo *to,
+				const struct kernel_siginfo *from)
 {
-	return __copy_siginfo_to_user32(to, from, in_x32_syscall());
-}
-int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
-			     const struct kernel_siginfo *from, bool x32_ABI)
-#endif
-{
-	struct compat_siginfo new;
-	memset(&new, 0, sizeof(new));
+	/*
+	 * This function does not work properly for SIGCHLD on x32,
+	 * but it does not need to as SIGCHLD never causes a coredump.
+	 */
+	memset(to, 0, sizeof(*to));
 
-	new.si_signo = from->si_signo;
-	new.si_errno = from->si_errno;
-	new.si_code  = 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:
-		new.si_pid = from->si_pid;
-		new.si_uid = from->si_uid;
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
 		break;
 	case SIL_TIMER:
-		new.si_tid     = from->si_tid;
-		new.si_overrun = from->si_overrun;
-		new.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:
-		new.si_band = from->si_band;
-		new.si_fd   = from->si_fd;
+		to->si_band = from->si_band;
+		to->si_fd   = from->si_fd;
 		break;
 	case SIL_FAULT:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
 		break;
 	case SIL_FAULT_MCEERR:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		new.si_addr_lsb = from->si_addr_lsb;
+		to->si_addr_lsb = from->si_addr_lsb;
 		break;
 	case SIL_FAULT_BNDERR:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		new.si_lower = ptr_to_compat(from->si_lower);
-		new.si_upper = ptr_to_compat(from->si_upper);
+		to->si_lower = ptr_to_compat(from->si_lower);
+		to->si_upper = ptr_to_compat(from->si_upper);
 		break;
 	case SIL_FAULT_PKUERR:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		new.si_pkey = from->si_pkey;
+		to->si_pkey = from->si_pkey;
 		break;
 	case SIL_CHLD:
-		new.si_pid    = from->si_pid;
-		new.si_uid    = from->si_uid;
-		new.si_status = from->si_status;
+		to->si_pid    = from->si_pid;
+		to->si_uid    = from->si_uid;
+		to->si_status = from->si_status;
+		to->si_utime = from->si_utime;
+		to->si_stime = from->si_stime;
 #ifdef CONFIG_X86_X32_ABI
 		if (x32_ABI) {
-			new._sifields._sigchld_x32._utime = from->si_utime;
-			new._sifields._sigchld_x32._stime = from->si_stime;
+			to->_sifields._sigchld_x32._utime = from->si_utime;
+			to->_sifields._sigchld_x32._stime = from->si_stime;
 		} else
 #endif
 		{
-			new.si_utime = from->si_utime;
-			new.si_stime = from->si_stime;
 		}
 		break;
 	case SIL_RT:
-		new.si_pid = from->si_pid;
-		new.si_uid = from->si_uid;
-		new.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:
-		new.si_call_addr = ptr_to_compat(from->si_call_addr);
-		new.si_syscall   = from->si_syscall;
-		new.si_arch      = from->si_arch;
+		to->si_call_addr = ptr_to_compat(from->si_call_addr);
+		to->si_syscall   = from->si_syscall;
+		to->si_arch      = from->si_arch;
 		break;
 	}
+}
+
+int copy_siginfo_to_user32(struct compat_siginfo __user *to,
+			   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 kernel_siginfo *from, bool x32_ABI)
+#endif
+{
+	struct compat_siginfo new;
+	copy_siginfo_to_external32(&new, from);
+#ifdef CONFIG_X86_X32_ABI
+	if (x32_ABI && from->si_signo == SIGCHLD) {
+		new._sifields._sigchld_x32._utime = from->si_utime;
+		new._sifields._sigchld_x32._stime = from->si_stime;
+	}
+#endif
 
 	if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
 		return -EFAULT;
-- 
2.25.0


WARNING: multiple messages have this Message-ID (diff)
From: ebiederm@xmission.com (Eric W. Biederman)
To: Christoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	linuxppc-dev@lists.ozlabs.org, Jeremy Kerr <jk@ozlabs.org>
Subject: [PATCH 1/2] signal: Factor copy_siginfo_to_external32 from copy_siginfo_to_user32
Date: Fri, 17 Apr 2020 16:09:22 -0500	[thread overview]
Message-ID: <87k12dakfx.fsf_-_@x220.int.ebiederm.org> (raw)
In-Reply-To: <87pnc5akhk.fsf@x220.int.ebiederm.org> (Eric W. Biederman's message of "Fri, 17 Apr 2020 16:08:23 -0500")


To remove the use of set_fs in the coredump code there needs to be a
way to convert a kernel siginfo to a userspace compat siginfo.

Call that function copy_siginfo_to_compat and factor it out of
copy_siginfo_to_user32.

The existence of x32 complicates this code.  On x32 SIGCHLD uses 64bit
times for utime and stime.  As only SIGCHLD is affected and SIGCHLD
never causes a coredump I have avoided handling that case.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 include/linux/compat.h |   1 +
 kernel/signal.c        | 108 +++++++++++++++++++++++------------------
 2 files changed, 63 insertions(+), 46 deletions(-)

diff --git a/include/linux/compat.h b/include/linux/compat.h
index 0480ba4db592..4962b254e550 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -402,6 +402,7 @@ 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);
+void copy_siginfo_to_external32(struct compat_siginfo *to, const struct kernel_siginfo *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,
diff --git a/kernel/signal.c b/kernel/signal.c
index e58a6c619824..578f196898cb 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3235,90 +3235,106 @@ int copy_siginfo_from_user(kernel_siginfo_t *to, const siginfo_t __user *from)
 }
 
 #ifdef CONFIG_COMPAT
-int copy_siginfo_to_user32(struct compat_siginfo __user *to,
-			   const struct kernel_siginfo *from)
-#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION)
+void copy_siginfo_to_external32(struct compat_siginfo *to,
+				const struct kernel_siginfo *from)
 {
-	return __copy_siginfo_to_user32(to, from, in_x32_syscall());
-}
-int __copy_siginfo_to_user32(struct compat_siginfo __user *to,
-			     const struct kernel_siginfo *from, bool x32_ABI)
-#endif
-{
-	struct compat_siginfo new;
-	memset(&new, 0, sizeof(new));
+	/*
+	 * This function does not work properly for SIGCHLD on x32,
+	 * but it does not need to as SIGCHLD never causes a coredump.
+	 */
+	memset(to, 0, sizeof(*to));
 
-	new.si_signo = from->si_signo;
-	new.si_errno = from->si_errno;
-	new.si_code  = 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:
-		new.si_pid = from->si_pid;
-		new.si_uid = from->si_uid;
+		to->si_pid = from->si_pid;
+		to->si_uid = from->si_uid;
 		break;
 	case SIL_TIMER:
-		new.si_tid     = from->si_tid;
-		new.si_overrun = from->si_overrun;
-		new.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:
-		new.si_band = from->si_band;
-		new.si_fd   = from->si_fd;
+		to->si_band = from->si_band;
+		to->si_fd   = from->si_fd;
 		break;
 	case SIL_FAULT:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
 		break;
 	case SIL_FAULT_MCEERR:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		new.si_addr_lsb = from->si_addr_lsb;
+		to->si_addr_lsb = from->si_addr_lsb;
 		break;
 	case SIL_FAULT_BNDERR:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		new.si_lower = ptr_to_compat(from->si_lower);
-		new.si_upper = ptr_to_compat(from->si_upper);
+		to->si_lower = ptr_to_compat(from->si_lower);
+		to->si_upper = ptr_to_compat(from->si_upper);
 		break;
 	case SIL_FAULT_PKUERR:
-		new.si_addr = ptr_to_compat(from->si_addr);
+		to->si_addr = ptr_to_compat(from->si_addr);
 #ifdef __ARCH_SI_TRAPNO
-		new.si_trapno = from->si_trapno;
+		to->si_trapno = from->si_trapno;
 #endif
-		new.si_pkey = from->si_pkey;
+		to->si_pkey = from->si_pkey;
 		break;
 	case SIL_CHLD:
-		new.si_pid    = from->si_pid;
-		new.si_uid    = from->si_uid;
-		new.si_status = from->si_status;
+		to->si_pid    = from->si_pid;
+		to->si_uid    = from->si_uid;
+		to->si_status = from->si_status;
+		to->si_utime = from->si_utime;
+		to->si_stime = from->si_stime;
 #ifdef CONFIG_X86_X32_ABI
 		if (x32_ABI) {
-			new._sifields._sigchld_x32._utime = from->si_utime;
-			new._sifields._sigchld_x32._stime = from->si_stime;
+			to->_sifields._sigchld_x32._utime = from->si_utime;
+			to->_sifields._sigchld_x32._stime = from->si_stime;
 		} else
 #endif
 		{
-			new.si_utime = from->si_utime;
-			new.si_stime = from->si_stime;
 		}
 		break;
 	case SIL_RT:
-		new.si_pid = from->si_pid;
-		new.si_uid = from->si_uid;
-		new.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:
-		new.si_call_addr = ptr_to_compat(from->si_call_addr);
-		new.si_syscall   = from->si_syscall;
-		new.si_arch      = from->si_arch;
+		to->si_call_addr = ptr_to_compat(from->si_call_addr);
+		to->si_syscall   = from->si_syscall;
+		to->si_arch      = from->si_arch;
 		break;
 	}
+}
+
+int copy_siginfo_to_user32(struct compat_siginfo __user *to,
+			   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 kernel_siginfo *from, bool x32_ABI)
+#endif
+{
+	struct compat_siginfo new;
+	copy_siginfo_to_external32(&new, from);
+#ifdef CONFIG_X86_X32_ABI
+	if (x32_ABI && from->si_signo == SIGCHLD) {
+		new._sifields._sigchld_x32._utime = from->si_utime;
+		new._sifields._sigchld_x32._stime = from->si_stime;
+	}
+#endif
 
 	if (copy_to_user(to, &new, sizeof(struct compat_siginfo)))
 		return -EFAULT;
-- 
2.25.0


  reply	other threads:[~2020-04-17 21:12 UTC|newest]

Thread overview: 65+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-14  7:01 remove set_fs calls from the exec and coredump code v2 Christoph Hellwig
2020-04-14  7:01 ` Christoph Hellwig
2020-04-14  7:01 ` [PATCH 1/8] powerpc/spufs: simplify spufs core dumping Christoph Hellwig
2020-04-14  7:01   ` Christoph Hellwig
2020-04-14  7:01 ` [PATCH 2/8] signal: clean up __copy_siginfo_to_user32 Christoph Hellwig
2020-04-14  7:01   ` Christoph Hellwig
2020-04-17 21:08   ` Eric W. Biederman
2020-04-17 21:08     ` Eric W. Biederman
2020-04-17 21:09     ` Eric W. Biederman [this message]
2020-04-17 21:09       ` [PATCH 1/2] signal: Factor copy_siginfo_to_external32 from copy_siginfo_to_user32 Eric W. Biederman
2020-04-18  8:05       ` Christophe Leroy
2020-04-18 11:55         ` Eric W. Biederman
2020-04-18 11:55           ` Eric W. Biederman
2020-04-19  8:13           ` Christoph Hellwig
2020-04-19  8:13             ` Christoph Hellwig
2020-04-19  9:46             ` Christophe Leroy
2020-04-19  9:54           ` Christophe Leroy
2020-04-19  8:05         ` Christoph Hellwig
2020-04-19  8:05           ` Christoph Hellwig
2020-04-17 21:09     ` [PATCH 2/2] signal: Remove the set_fs in binfmt_elf.c:fill_siginfo_note Eric W. Biederman
2020-04-17 21:09       ` Eric W. Biederman
2020-04-19  8:03     ` [PATCH 2/8] signal: clean up __copy_siginfo_to_user32 Christoph Hellwig
2020-04-19  8:03       ` Christoph Hellwig
2020-04-14  7:01 ` [PATCH 3/8] signal: replace __copy_siginfo_to_user32 with to_compat_siginfo Christoph Hellwig
2020-04-14  7:01   ` Christoph Hellwig
2020-04-14 14:00   ` Arnd Bergmann
2020-04-14 14:00     ` Arnd Bergmann
2020-04-14  7:01 ` [PATCH 4/8] binfmt_elf: open code copy_siginfo_to_user to kernelspace buffer Christoph Hellwig
2020-04-14  7:01   ` Christoph Hellwig
2020-04-14 13:15   ` Arnd Bergmann
2020-04-14 13:15     ` Arnd Bergmann
2020-04-15  7:45     ` Christoph Hellwig
2020-04-15  7:45       ` Christoph Hellwig
2020-04-15  8:20       ` Arnd Bergmann
2020-04-15  8:20         ` Arnd Bergmann
2020-04-17 13:27         ` Christoph Hellwig
2020-04-17 13:27           ` Christoph Hellwig
2020-04-17 18:10           ` Eric W. Biederman
2020-04-17 18:10             ` Eric W. Biederman
2020-04-17 20:06             ` Arnd Bergmann
2020-04-17 20:06               ` Arnd Bergmann
2020-04-15  3:01   ` Michael Ellerman
2020-04-15  3:01     ` Michael Ellerman
2020-04-15  6:19     ` Christoph Hellwig
2020-04-15  6:19       ` Christoph Hellwig
2020-04-14  7:01 ` [PATCH 5/8] binfmt_elf: remove the set_fs(KERNEL_DS) in elf_core_dump Christoph Hellwig
2020-04-14  7:01   ` Christoph Hellwig
2020-04-14  7:01 ` [PATCH 6/8] binfmt_elf_fdpic: remove the set_fs(KERNEL_DS) in elf_fdpic_core_dump Christoph Hellwig
2020-04-14  7:01   ` Christoph Hellwig
2020-04-14  7:01 ` [PATCH 7/8] exec: simplify the copy_strings_kernel calling convention Christoph Hellwig
2020-04-14  7:01   ` Christoph Hellwig
2020-04-14  7:01 ` [PATCH 8/8] exec: open code copy_string_kernel Christoph Hellwig
2020-04-14  7:01   ` Christoph Hellwig
2020-04-18  8:15   ` Christophe Leroy
2020-04-18  8:15     ` Christophe Leroy
2020-04-19  8:06     ` Christoph Hellwig
2020-04-19  8:06       ` Christoph Hellwig
2020-04-19  9:44       ` Christophe Leroy
2020-04-19  9:44         ` Christophe Leroy
2020-04-17 22:41 ` remove set_fs calls from the exec and coredump code v2 Eric W. Biederman
2020-04-17 22:41   ` Eric W. Biederman
2020-04-19  8:19   ` Christoph Hellwig
2020-04-19  8:19     ` Christoph Hellwig
2020-04-19 11:50     ` Eric W. Biederman
2020-04-19 11:50       ` Eric W. Biederman

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