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authorMarkos Chandras <markos.chandras@imgtec.com>2015-09-25 08:17:42 +0100
committerRalf Baechle <ralf@linux-mips.org>2015-10-04 12:10:56 +0200
commitd218af78492a36a4ae607c08fedfb59258440314 (patch)
treefb9a1d1c08161c39c6f8b8db04b0cc116959718b /arch
parent66803dd9198cb57a4b7ed4a6846a63ab1d59a2e0 (diff)
downloadlinux-linaro-stable-d218af78492a36a4ae607c08fedfb59258440314.tar.gz
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')
-rw-r--r--arch/mips/kernel/scall32-o32.S39
-rw-r--r--arch/mips/kernel/scall64-64.S38
-rw-r--r--arch/mips/kernel/scall64-n32.S19
-rw-r--r--arch/mips/kernel/scall64-o32.S19
4 files changed, 42 insertions, 73 deletions
diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S
index d06e30c1e4cd..65a74e4f0f45 100644
--- a/arch/mips/kernel/scall32-o32.S
+++ b/arch/mips/kernel/scall32-o32.S
@@ -36,16 +36,8 @@ NESTED(handle_sys, PT_SIZE, sp)
lw t1, PT_EPC(sp) # skip syscall on return
subu v0, v0, __NR_O32_Linux # check syscall number
- sltiu t0, v0, __NR_O32_Linux_syscalls + 1
addiu t1, 4 # skip to next instruction
sw t1, PT_EPC(sp)
- beqz t0, illegal_syscall
-
- sll t0, v0, 2
- la t1, sys_call_table
- addu t1, t0
- lw t2, (t1) # syscall routine
- beqz t2, illegal_syscall
sw a3, PT_R26(sp) # save a3 for syscall restarting
@@ -96,6 +88,16 @@ loads_done:
li t1, _TIF_WORK_SYSCALL_ENTRY
and t0, t1
bnez t0, syscall_trace_entry # -> yes
+syscall_common:
+ sltiu t0, v0, __NR_O32_Linux_syscalls + 1
+ beqz t0, illegal_syscall
+
+ sll t0, v0, 2
+ la t1, sys_call_table
+ addu t1, t0
+ lw t2, (t1) # syscall routine
+
+ beqz t2, illegal_syscall
jalr t2 # Do The Real Thing (TM)
@@ -116,7 +118,7 @@ o32_syscall_exit:
syscall_trace_entry:
SAVE_STATIC
- move s0, t2
+ move s0, v0
move a0, sp
/*
@@ -129,27 +131,18 @@ syscall_trace_entry:
1: jal syscall_trace_enter
- bltz v0, 2f # seccomp failed? Skip syscall
+ bltz v0, 1f # seccomp failed? Skip syscall
+
+ move v0, s0 # restore syscall
- move t0, s0
RESTORE_STATIC
lw a0, PT_R4(sp) # Restore argument registers
lw a1, PT_R5(sp)
lw a2, PT_R6(sp)
lw a3, PT_R7(sp)
- jalr t0
-
- li t0, -EMAXERRNO - 1 # error?
- sltu t0, t0, v0
- sw t0, PT_R7(sp) # set error flag
- beqz t0, 1f
-
- lw t1, PT_R2(sp) # syscall number
- negu v0 # error
- sw t1, PT_R0(sp) # save it for syscall restarting
-1: sw v0, PT_R2(sp) # result
+ j syscall_common
-2: j syscall_exit
+1: j syscall_exit
/* ------------------------------------------------------------------------ */
diff --git a/arch/mips/kernel/scall64-64.S b/arch/mips/kernel/scall64-64.S
index 428c2cd2326c..e732981cf99f 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. */
diff --git a/arch/mips/kernel/scall64-n32.S b/arch/mips/kernel/scall64-n32.S
index 3868cf4c83df..c79484397584 100644
--- a/arch/mips/kernel/scall64-n32.S
+++ b/arch/mips/kernel/scall64-n32.S
@@ -52,6 +52,7 @@ NESTED(handle_sysn32, PT_SIZE, sp)
and t0, t1, t0
bnez t0, n32_syscall_trace_entry
+syscall_common:
jalr t2 # Do The Real Thing (TM)
li t0, -EMAXERRNO - 1 # error?
@@ -75,9 +76,9 @@ n32_syscall_trace_entry:
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 t2, s0
RESTORE_STATIC
ld a0, PT_R4(sp) # Restore argument registers
ld a1, PT_R5(sp)
@@ -85,19 +86,9 @@ n32_syscall_trace_entry:
ld a3, PT_R7(sp)
ld a4, PT_R8(sp)
ld a5, PT_R9(sp)
- jalr t0
+ j syscall_common
- 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
-
-2: j syscall_exit
+1: j syscall_exit
not_n32_scall:
/* This is not an n32 compatibility syscall, pass it on to
diff --git a/arch/mips/kernel/scall64-o32.S b/arch/mips/kernel/scall64-o32.S
index 6622980d82ea..6369cfd390c6 100644
--- a/arch/mips/kernel/scall64-o32.S
+++ b/arch/mips/kernel/scall64-o32.S
@@ -87,6 +87,7 @@ loads_done:
and t0, t1, t0
bnez t0, trace_a_syscall
+syscall_common:
jalr t2 # Do The Real Thing (TM)
li t0, -EMAXERRNO - 1 # error?
@@ -130,9 +131,9 @@ trace_a_syscall:
1: jal syscall_trace_enter
- bltz v0, 2f # seccomp failed? Skip syscall
+ bltz v0, 1f # seccomp failed? Skip syscall
- move t0, s0
+ move t2, s0
RESTORE_STATIC
ld a0, PT_R4(sp) # Restore argument registers
ld a1, PT_R5(sp)
@@ -142,19 +143,9 @@ trace_a_syscall:
ld a5, PT_R9(sp)
ld a6, PT_R10(sp)
ld a7, PT_R11(sp) # For indirect syscalls
- jalr t0
+ j syscall_common
- 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
-
-2: j syscall_exit
+1: j syscall_exit
/* ------------------------------------------------------------------------ */