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| author | Markos Chandras <markos.chandras@imgtec.com> | 2015-09-25 07:17:42 (GMT) |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2015-10-04 10:10:56 (GMT) |
| commit | d218af78492a36a4ae607c08fedfb59258440314 (patch) | |
| tree | fb9a1d1c08161c39c6f8b8db04b0cc116959718b /arch/mips/kernel/scall64-64.S | |
| parent | 66803dd9198cb57a4b7ed4a6846a63ab1d59a2e0 (diff) | |
| download | linux-d218af78492a36a4ae607c08fedfb59258440314.tar.xz | |
MIPS: scall: Always run the seccomp syscall filters
The MIPS syscall handler code used to return -ENOSYS on invalid
syscalls. Whilst this is expected, it caused problems for seccomp
filters because the said filters never had the change to run since
the code returned -ENOSYS before triggering them. This caused
problems on the chromium testsuite for filters looking for invalid
syscalls. This has now changed and the seccomp filters are always
run even if the syscall is invalid. We return -ENOSYS once we
return from the seccomp filters. Moreover, similar codepaths have
been merged in the process which simplifies somewhat the overall
syscall code.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11236/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel/scall64-64.S')
| -rw-r--r-- | arch/mips/kernel/scall64-64.S | 38 |
1 files changed, 16 insertions, 22 deletions
diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S index 428c2cd..e732981 100644 --- a/arch/mips/kernel/scall64-64.S +++ b/arch/mips/kernel/scall64-64.S @@ -39,18 +39,11 @@ NESTED(handle_sys64, PT_SIZE, sp) .set at #endif - dsubu t0, v0, __NR_64_Linux # check syscall number - sltiu t0, t0, __NR_64_Linux_syscalls + 1 #if !defined(CONFIG_MIPS32_O32) && !defined(CONFIG_MIPS32_N32) ld t1, PT_EPC(sp) # skip syscall on return daddiu t1, 4 # skip to next instruction sd t1, PT_EPC(sp) #endif - beqz t0, illegal_syscall - - dsll t0, v0, 3 # offset into table - ld t2, (sys_call_table - (__NR_64_Linux * 8))(t0) - # syscall routine sd a3, PT_R26(sp) # save a3 for syscall restarting @@ -59,6 +52,17 @@ NESTED(handle_sys64, PT_SIZE, sp) and t0, t1, t0 bnez t0, syscall_trace_entry +syscall_common: + dsubu t2, v0, __NR_64_Linux + sltiu t0, t2, __NR_64_Linux_syscalls + 1 + beqz t0, illegal_syscall + + dsll t0, t2, 3 # offset into table + dla t2, sys_call_table + daddu t0, t2, t0 + ld t2, (t0) # syscall routine + beqz t2, illegal_syscall + jalr t2 # Do The Real Thing (TM) li t0, -EMAXERRNO - 1 # error? @@ -78,14 +82,14 @@ n64_syscall_exit: syscall_trace_entry: SAVE_STATIC - move s0, t2 + move s0, v0 move a0, sp move a1, v0 jal syscall_trace_enter - bltz v0, 2f # seccomp failed? Skip syscall + bltz v0, 1f # seccomp failed? Skip syscall - move t0, s0 + move v0, s0 RESTORE_STATIC ld a0, PT_R4(sp) # Restore argument registers ld a1, PT_R5(sp) @@ -93,19 +97,9 @@ syscall_trace_entry: ld a3, PT_R7(sp) ld a4, PT_R8(sp) ld a5, PT_R9(sp) - jalr t0 - - li t0, -EMAXERRNO - 1 # error? - sltu t0, t0, v0 - sd t0, PT_R7(sp) # set error flag - beqz t0, 1f - - ld t1, PT_R2(sp) # syscall number - dnegu v0 # error - sd t1, PT_R0(sp) # save it for syscall restarting -1: sd v0, PT_R2(sp) # result + j syscall_common -2: j syscall_exit +1: j syscall_exit illegal_syscall: /* This also isn't a 64-bit syscall, throw an error. */ |