* [PATCH v8 0/3] Add kernel seccomp support for m68k
@ 2022-01-13 1:09 Michael Schmitz
2022-01-13 1:09 ` [PATCH v8 1/3] m68k/kernel - wire up syscall_trace_enter/leave " Michael Schmitz
` (4 more replies)
0 siblings, 5 replies; 8+ messages in thread
From: Michael Schmitz @ 2022-01-13 1:09 UTC (permalink / raw)
To: linux-m68k, geert; +Cc: ebiederm, viro
Respin of m68k kernel seccomp support, again.
I have split the (MMU) m68k switch to syscall_trace_enter()/
syscall_trace_leave() patch from the patch adding return code
checks for syscall_trace_enter() as suggested by Al Viro.
Patch 1 could now replace Eric's patch 'Stop open coding
ptrace_report_syscall'.
Rest of the series remains unchanged.
Cheers,
Michael
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v8 1/3] m68k/kernel - wire up syscall_trace_enter/leave for m68k
2022-01-13 1:09 [PATCH v8 0/3] Add kernel seccomp support for m68k Michael Schmitz
@ 2022-01-13 1:09 ` Michael Schmitz
2022-01-13 1:09 ` [PATCH v8 2/3] m68k/kernel - check syscall_trace_enter() return code on m68k Michael Schmitz
` (3 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Michael Schmitz @ 2022-01-13 1:09 UTC (permalink / raw)
To: linux-m68k, geert; +Cc: ebiederm, viro, Michael Schmitz
m68k (other than Coldfire) uses syscall_trace for both trace entry
and trace exit. Seccomp support requires separate entry points for
trace entry and exit which are already provided for Coldfire.
Replace syscall_trace by syscall_trace_enter and syscall_trace_leave
in preparation for seccomp support.
No regression seen in testing with strace on ARAnyM.
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
--
Changes from v7:
Al Viro:
- split first patch to separate the switch to
syscall_trace_enter/leave() from return code checks
Changes from v6:
Geert Uytterhoeven:
- add syscall_trace_enter() return code check for 68000
and coldfire
Changes from v5:
- add comment to explain optimization
Changes from v4:
Andreas Schwab:
- optimize return code test (addql #1,%d0 for cmpil #-1,%d0)
- spelling fix in commit message
Changes from v3:
- change syscall_trace_enter return code test from !=0 to ==-1
revert syscall trace return code checks
---
arch/m68k/kernel/entry.S | 4 ++--
arch/m68k/kernel/ptrace.c | 17 -----------------
2 files changed, 2 insertions(+), 19 deletions(-)
diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S
index 9434fca68de5..18f278bdbd21 100644
--- a/arch/m68k/kernel/entry.S
+++ b/arch/m68k/kernel/entry.S
@@ -181,7 +181,7 @@ do_trace_entry:
movel #-ENOSYS,%sp@(PT_OFF_D0)| needed for strace
subql #4,%sp
SAVE_SWITCH_STACK
- jbsr syscall_trace
+ jbsr syscall_trace_enter
RESTORE_SWITCH_STACK
addql #4,%sp
movel %sp@(PT_OFF_ORIG_D0),%d0
@@ -194,7 +194,7 @@ badsys:
do_trace_exit:
subql #4,%sp
SAVE_SWITCH_STACK
- jbsr syscall_trace
+ jbsr syscall_trace_leave
RESTORE_SWITCH_STACK
addql #4,%sp
jra .Lret_from_exception
diff --git a/arch/m68k/kernel/ptrace.c b/arch/m68k/kernel/ptrace.c
index 94b3b274186d..74d58a82a135 100644
--- a/arch/m68k/kernel/ptrace.c
+++ b/arch/m68k/kernel/ptrace.c
@@ -271,22 +271,6 @@ long arch_ptrace(struct task_struct *child, long request,
return -EIO;
}
-asmlinkage void syscall_trace(void)
-{
- ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
- ? 0x80 : 0));
- /*
- * this isn't the same as continuing with a signal, but it will do
- * for normal use. strace only continues with a signal if the
- * stopping signal is not SIGTRAP. -brl
- */
- if (current->exit_code) {
- send_sig(current->exit_code, current, 1);
- current->exit_code = 0;
- }
-}
-
-#if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
asmlinkage int syscall_trace_enter(void)
{
int ret = 0;
@@ -301,4 +285,3 @@ asmlinkage void syscall_trace_leave(void)
if (test_thread_flag(TIF_SYSCALL_TRACE))
tracehook_report_syscall_exit(task_pt_regs(current), 0);
}
-#endif /* CONFIG_COLDFIRE */
--
2.17.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v8 2/3] m68k/kernel - check syscall_trace_enter() return code on m68k
2022-01-13 1:09 [PATCH v8 0/3] Add kernel seccomp support for m68k Michael Schmitz
2022-01-13 1:09 ` [PATCH v8 1/3] m68k/kernel - wire up syscall_trace_enter/leave " Michael Schmitz
@ 2022-01-13 1:09 ` Michael Schmitz
2022-01-13 1:09 ` [PATCH v8 3/3] m68k: add kernel seccomp support Michael Schmitz
` (2 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Michael Schmitz @ 2022-01-13 1:09 UTC (permalink / raw)
To: linux-m68k, geert; +Cc: ebiederm, viro, Michael Schmitz
Check return code of syscall_trace_enter(), and skip syscall
if -1. Return code will be left at what had been set by
ptrace or seccomp (in regs->d0).
No regression seen in testing with strace on ARAnyM.
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
--
Changes from v7:
Al Viro:
- split return code checks from switch to syscall_trace_enter()
Changes from v6:
Geert Uytterhoeven:
- add syscall_trace_enter() return code check for 68000
and coldfire
Changes from v5:
- add comment to explain optimization
Changes from v4:
Andreas Schwab:
- optimize return code test (addql #1,%d0 for cmpil #-1,%d0)
- spelling fix in commit message
Changes from v3:
- change syscall_trace_enter return code test from !=0 to ==-1
---
arch/m68k/68000/entry.S | 2 ++
arch/m68k/coldfire/entry.S | 2 ++
arch/m68k/kernel/entry.S | 2 ++
3 files changed, 6 insertions(+)
diff --git a/arch/m68k/68000/entry.S b/arch/m68k/68000/entry.S
index 997b54933015..7d63e2f1555a 100644
--- a/arch/m68k/68000/entry.S
+++ b/arch/m68k/68000/entry.S
@@ -45,6 +45,8 @@ do_trace:
jbsr syscall_trace_enter
RESTORE_SWITCH_STACK
addql #4,%sp
+ addql #1,%d0
+ jeq ret_from_exception
movel %sp@(PT_OFF_ORIG_D0),%d1
movel #-ENOSYS,%d0
cmpl #NR_syscalls,%d1
diff --git a/arch/m68k/coldfire/entry.S b/arch/m68k/coldfire/entry.S
index 9f337c70243a..35104c5417ff 100644
--- a/arch/m68k/coldfire/entry.S
+++ b/arch/m68k/coldfire/entry.S
@@ -90,6 +90,8 @@ ENTRY(system_call)
jbsr syscall_trace_enter
RESTORE_SWITCH_STACK
addql #4,%sp
+ addql #1,%d0
+ jeq ret_from_exception
movel %d3,%a0
jbsr %a0@
movel %d0,%sp@(PT_OFF_D0) /* save the return value */
diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S
index 18f278bdbd21..0d5b7085d76f 100644
--- a/arch/m68k/kernel/entry.S
+++ b/arch/m68k/kernel/entry.S
@@ -184,6 +184,8 @@ do_trace_entry:
jbsr syscall_trace_enter
RESTORE_SWITCH_STACK
addql #4,%sp
+ addql #1,%d0 | optimization for cmpil #-1,%d0
+ jeq ret_from_syscall
movel %sp@(PT_OFF_ORIG_D0),%d0
cmpl #NR_syscalls,%d0
jcs syscall
--
2.17.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v8 3/3] m68k: add kernel seccomp support
2022-01-13 1:09 [PATCH v8 0/3] Add kernel seccomp support for m68k Michael Schmitz
2022-01-13 1:09 ` [PATCH v8 1/3] m68k/kernel - wire up syscall_trace_enter/leave " Michael Schmitz
2022-01-13 1:09 ` [PATCH v8 2/3] m68k/kernel - check syscall_trace_enter() return code on m68k Michael Schmitz
@ 2022-01-13 1:09 ` Michael Schmitz
2022-01-14 22:51 ` [PATCH v8 0/3] Add kernel seccomp support for m68k John Paul Adrian Glaubitz
2022-01-17 18:06 ` Eric W. Biederman
4 siblings, 0 replies; 8+ messages in thread
From: Michael Schmitz @ 2022-01-13 1:09 UTC (permalink / raw)
To: linux-m68k, geert; +Cc: ebiederm, viro, Michael Schmitz
Add secure_computing() call to syscall_trace_enter to actually
filter system calls.
Add necessary arch Kconfig options, define TIF_SECCOMP trace
flag and provide basic seccomp filter support in asm/syscall.h
syscall_get_nr currently uses the syscall nr stored in orig_d0
because we change d0 to a default return code before starting a
syscall trace. This may be inconsistent with syscall_rollback
copying orig_d0 to d0 (which we never check upon return from
trace). We use d0 for the return code from syscall_trace_enter
in entry.S currently, and could perhaps expand that to store
a new syscall number returned by the seccomp filter before
executing the syscall. This clearly needs some discussion.
Compiles (for Atari) and boots on ARAnyM, otherwise untested.
Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
--
Changes from v6:
Geert Uytterhoeven:
- add syscall_get_error(), syscall_get_return_value(), and
syscall_set_arguments() (not needed to compile!)
Changes from v5:
Geert Uytterhoeven:
- correct wrong offset for d1-d5 register copy
- update Documentation/features/seccomp/seccomp-filter/arch-support.txt
add syscall_get_error(), syscall_get_return_value(), syscall_set_arguments()
---
.../seccomp/seccomp-filter/arch-support.txt | 2 +-
arch/m68k/Kconfig | 2 +
arch/m68k/include/asm/seccomp.h | 11 ++++
arch/m68k/include/asm/syscall.h | 56 +++++++++++++++++++
arch/m68k/include/asm/thread_info.h | 2 +
arch/m68k/kernel/ptrace.c | 5 ++
6 files changed, 77 insertions(+), 1 deletion(-)
create mode 100644 arch/m68k/include/asm/seccomp.h
diff --git a/Documentation/features/seccomp/seccomp-filter/arch-support.txt b/Documentation/features/seccomp/seccomp-filter/arch-support.txt
index 26eec58ab819..be71f2066981 100644
--- a/Documentation/features/seccomp/seccomp-filter/arch-support.txt
+++ b/Documentation/features/seccomp/seccomp-filter/arch-support.txt
@@ -14,7 +14,7 @@
| h8300: | TODO |
| hexagon: | TODO |
| ia64: | TODO |
- | m68k: | TODO |
+ | m68k: | ok |
| microblaze: | TODO |
| mips: | ok |
| nds32: | TODO |
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 4cae3fbe7f97..8c4f6b3b3ddd 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -18,6 +18,8 @@ config M68K
select GENERIC_IOMAP
select GENERIC_IRQ_SHOW
select HAVE_AOUT if MMU
+ select HAVE_ARCH_SECCOMP
+ select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ASM_MODVERSIONS
select HAVE_DEBUG_BUGVERBOSE
select HAVE_EFFICIENT_UNALIGNED_ACCESS if !CPU_HAS_NO_UNALIGNED
diff --git a/arch/m68k/include/asm/seccomp.h b/arch/m68k/include/asm/seccomp.h
new file mode 100644
index 000000000000..de8a94e1fb3f
--- /dev/null
+++ b/arch/m68k/include/asm/seccomp.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_SECCOMP_H
+#define _ASM_SECCOMP_H
+
+#include <asm-generic/seccomp.h>
+
+#define SECCOMP_ARCH_NATIVE AUDIT_ARCH_M68K
+#define SECCOMP_ARCH_NATIVE_NR NR_syscalls
+#define SECCOMP_ARCH_NATIVE_NAME "m68k"
+
+#endif /* _ASM_SECCOMP_H */
diff --git a/arch/m68k/include/asm/syscall.h b/arch/m68k/include/asm/syscall.h
index 465ac039be09..2b49ad725655 100644
--- a/arch/m68k/include/asm/syscall.h
+++ b/arch/m68k/include/asm/syscall.h
@@ -4,6 +4,62 @@
#include <uapi/linux/audit.h>
+#include <asm/unistd.h>
+
+extern const unsigned long sys_call_table[];
+
+static inline int syscall_get_nr(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs->orig_d0;
+}
+
+static inline void syscall_rollback(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ regs->d0 = regs->orig_d0;
+}
+
+static inline long syscall_get_error(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ unsigned long error = regs->d0;
+ return IS_ERR_VALUE(error) ? error : 0;
+}
+
+static inline long syscall_get_return_value(struct task_struct *task,
+ struct pt_regs *regs)
+{
+ return regs->d0;
+}
+
+static inline void syscall_set_return_value(struct task_struct *task,
+ struct pt_regs *regs,
+ int error, long val)
+{
+ regs->d0 = (long) error ? error : val;
+}
+
+static inline void syscall_get_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned long *args)
+{
+ args[0] = regs->orig_d0;
+ args++;
+
+ memcpy(args, ®s->d1, 5 * sizeof(args[0]));
+}
+
+static inline void syscall_set_arguments(struct task_struct *task,
+ struct pt_regs *regs,
+ unsigned long *args)
+{
+ regs->orig_d0 = args[0];
+ args++;
+
+ memcpy(®s->d1, args, 5 * sizeof(args[0]));
+}
+
static inline int syscall_get_arch(struct task_struct *task)
{
return AUDIT_ARCH_M68K;
diff --git a/arch/m68k/include/asm/thread_info.h b/arch/m68k/include/asm/thread_info.h
index c952658ba792..31be2ad999ca 100644
--- a/arch/m68k/include/asm/thread_info.h
+++ b/arch/m68k/include/asm/thread_info.h
@@ -61,6 +61,7 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_NOTIFY_RESUME 5 /* callback before returning to user */
#define TIF_SIGPENDING 6 /* signal pending */
#define TIF_NEED_RESCHED 7 /* rescheduling necessary */
+#define TIF_SECCOMP 13 /* seccomp syscall filtering active */
#define TIF_DELAYED_TRACE 14 /* single step a syscall */
#define TIF_SYSCALL_TRACE 15 /* syscall trace active */
#define TIF_MEMDIE 16 /* is terminating due to OOM killer */
@@ -69,6 +70,7 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
+#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_DELAYED_TRACE (1 << TIF_DELAYED_TRACE)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_MEMDIE (1 << TIF_MEMDIE)
diff --git a/arch/m68k/kernel/ptrace.c b/arch/m68k/kernel/ptrace.c
index 74d58a82a135..bc2490c3fb52 100644
--- a/arch/m68k/kernel/ptrace.c
+++ b/arch/m68k/kernel/ptrace.c
@@ -19,6 +19,7 @@
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/signal.h>
+#include <linux/seccomp.h>
#include <linux/tracehook.h>
#include <linux/uaccess.h>
@@ -277,6 +278,10 @@ asmlinkage int syscall_trace_enter(void)
if (test_thread_flag(TIF_SYSCALL_TRACE))
ret = tracehook_report_syscall_entry(task_pt_regs(current));
+
+ if (secure_computing() == -1)
+ return -1;
+
return ret;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v8 0/3] Add kernel seccomp support for m68k
2022-01-13 1:09 [PATCH v8 0/3] Add kernel seccomp support for m68k Michael Schmitz
` (2 preceding siblings ...)
2022-01-13 1:09 ` [PATCH v8 3/3] m68k: add kernel seccomp support Michael Schmitz
@ 2022-01-14 22:51 ` John Paul Adrian Glaubitz
2022-01-17 20:49 ` Michael Schmitz
2022-01-17 18:06 ` Eric W. Biederman
4 siblings, 1 reply; 8+ messages in thread
From: John Paul Adrian Glaubitz @ 2022-01-14 22:51 UTC (permalink / raw)
To: Michael Schmitz, linux-m68k, geert; +Cc: ebiederm, viro
Hi!
On 1/13/22 02:09, Michael Schmitz wrote:
> Respin of m68k kernel seccomp support, again.
>
> I have split the (MMU) m68k switch to syscall_trace_enter()/
> syscall_trace_leave() patch from the patch adding return code
> checks for syscall_trace_enter() as suggested by Al Viro.
>
> Patch 1 could now replace Eric's patch 'Stop open coding
> ptrace_report_syscall'.
>
> Rest of the series remains unchanged.
I will try to test this series within the next days. I'd like to see this
finally getting merged as there is a number of packages in Debian that
depend on libsecomp being available and there currently cannot be built
on m68k.
Adrian
--
.''`. John Paul Adrian Glaubitz
: :' : Debian Developer - glaubitz@debian.org
`. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
`- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v8 0/3] Add kernel seccomp support for m68k
2022-01-13 1:09 [PATCH v8 0/3] Add kernel seccomp support for m68k Michael Schmitz
` (3 preceding siblings ...)
2022-01-14 22:51 ` [PATCH v8 0/3] Add kernel seccomp support for m68k John Paul Adrian Glaubitz
@ 2022-01-17 18:06 ` Eric W. Biederman
2022-01-17 20:47 ` Michael Schmitz
4 siblings, 1 reply; 8+ messages in thread
From: Eric W. Biederman @ 2022-01-17 18:06 UTC (permalink / raw)
To: Michael Schmitz; +Cc: linux-m68k, geert, viro
Michael Schmitz <schmitzmic@gmail.com> writes:
> Respin of m68k kernel seccomp support, again.
>
> I have split the (MMU) m68k switch to syscall_trace_enter()/
> syscall_trace_leave() patch from the patch adding return code
> checks for syscall_trace_enter() as suggested by Al Viro.
>
> Patch 1 could now replace Eric's patch 'Stop open coding
> ptrace_report_syscall'.
That change has merged and should show up in v5.17-rc1, but that should
not matter in practice. This series just deletes the function I
modified and replaces it with something that is equivalent for my
purposes.
> Rest of the series remains unchanged.
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Eric
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v8 0/3] Add kernel seccomp support for m68k
2022-01-17 18:06 ` Eric W. Biederman
@ 2022-01-17 20:47 ` Michael Schmitz
0 siblings, 0 replies; 8+ messages in thread
From: Michael Schmitz @ 2022-01-17 20:47 UTC (permalink / raw)
To: Eric W. Biederman; +Cc: linux-m68k, geert, viro
Hi Eric,
Am 18.01.2022 um 07:06 schrieb Eric W. Biederman:
> Michael Schmitz <schmitzmic@gmail.com> writes:
>
>> Respin of m68k kernel seccomp support, again.
>>
>> I have split the (MMU) m68k switch to syscall_trace_enter()/
>> syscall_trace_leave() patch from the patch adding return code
>> checks for syscall_trace_enter() as suggested by Al Viro.
>>
>> Patch 1 could now replace Eric's patch 'Stop open coding
>> ptrace_report_syscall'.
>
> That change has merged and should show up in v5.17-rc1, but that should
> not matter in practice. This series just deletes the function I
> modified and replaces it with something that is equivalent for my
> purposes.
Thanks - I'll watch out for your patch to show up in 5.17-rc1 before
respinning again.
>
>> Rest of the series remains unchanged.
>
> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Thanks,
Michael
>
> Eric
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v8 0/3] Add kernel seccomp support for m68k
2022-01-14 22:51 ` [PATCH v8 0/3] Add kernel seccomp support for m68k John Paul Adrian Glaubitz
@ 2022-01-17 20:49 ` Michael Schmitz
0 siblings, 0 replies; 8+ messages in thread
From: Michael Schmitz @ 2022-01-17 20:49 UTC (permalink / raw)
To: John Paul Adrian Glaubitz, linux-m68k, geert; +Cc: ebiederm, viro
Hi Adrian,
Am 15.01.2022 um 11:51 schrieb John Paul Adrian Glaubitz:
> Hi!
>
> On 1/13/22 02:09, Michael Schmitz wrote:
>> Respin of m68k kernel seccomp support, again.
>>
>> I have split the (MMU) m68k switch to syscall_trace_enter()/
>> syscall_trace_leave() patch from the patch adding return code
>> checks for syscall_trace_enter() as suggested by Al Viro.
>>
>> Patch 1 could now replace Eric's patch 'Stop open coding
>> ptrace_report_syscall'.
>>
>> Rest of the series remains unchanged.
>
> I will try to test this series within the next days. I'd like to see this
> finally getting merged as there is a number of packages in Debian that
> depend on libsecomp being available and there currently cannot be built
> on m68k.
Thanks - your tests might help convincing Geert (and explain why my
selftests never showed much improvement - missing modules perhaps?).
Cheers,
Michael
>
> Adrian
>
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-01-17 20:50 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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2022-01-13 1:09 ` [PATCH v8 2/3] m68k/kernel - check syscall_trace_enter() return code on m68k Michael Schmitz
2022-01-13 1:09 ` [PATCH v8 3/3] m68k: add kernel seccomp support Michael Schmitz
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