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| author |   Markos Chandras <markos.chandras@imgtec.com> | 2014-01-22 14:40:03 +0000 |
|---|---|---|
| committer |   Ralf Baechle <ralf@linux-mips.org> | 2014-03-26 23:09:08 +0100 |
| commit | 4c21b8fd8f146a22e1eaf92833a32e51f560e82a (patch) | |
| tree | 4d784859ce5b207837ddb574e26264d78db33c74 /arch/mips/kernel/scall32-o32.S | |
| parent | MIPS: kernel: scalls: Skip the syscall if denied by the seccomp filter (diff) | |
| download | linux-dev-4c21b8fd8f146a22e1eaf92833a32e51f560e82a.tar.xz linux-dev-4c21b8fd8f146a22e1eaf92833a32e51f560e82a.zip | |
MIPS: seccomp: Handle indirect system calls (o32)
When userland uses syscall() to perform an indirect system call
the actually system call that needs to be checked by the filter
is on the first argument. The kernel code needs to handle this case
by looking at the original syscall number in v0 and if it's
NR_syscall, then it needs to examine the first argument to
identify the real system call that will be executed.
Similarly, we need to 'virtually' shift the syscall() arguments
so the syscall_get_arguments() function can fetch the correct
arguments for the indirect system call.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6404/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/scall32-o32.S')
| -rw-r--r-- | arch/mips/kernel/scall32-o32.S | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S index 1789a801802e..ffe89139e0f9 100644 --- a/arch/mips/kernel/scall32-o32.S +++ b/arch/mips/kernel/scall32-o32.S @@ -118,7 +118,16 @@ syscall_trace_entry: SAVE_STATIC move s0, t2 move a0, sp - jal syscall_trace_enter + + /* + * syscall number is in v0 unless we called syscall(__NR_###) + * where the real syscall number is in a0 + */ + addiu a1, v0, __NR_O32_Linux + bnez v0, 1f /* __NR_syscall at offset 0 */ + lw a1, PT_R4(sp) + +1: jal syscall_trace_enter bltz v0, 2f # seccomp failed? Skip syscall |