[PATCH v2 04/16] seccomp: Check in_compat_syscall, not is_compat_task, in strict mode

Andy Lutomirski
2016-01-25T22:24:18Z

Seccomp wants to know the syscall bitness, not the caller task
bitness, when it selects the syscall whitelist.

As far as I know, this makes no difference on any architecture, so
it's not a security problem. (It generates identical code
everywhere except sparc, and, on sparc, the syscall numbering is the
same for both ABIs.)

Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
kernel/seccomp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 580ac2d4024f..26858fa43a60 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -395,7 +395,7 @@ seccomp_prepare_user_filter(const char __user *user_filter)
struct seccomp_filter *filter = ERR_PTR(-EFAULT);

#ifdef CONFIG_COMPAT
- if (is_compat_task()) {
+ if (in_compat_syscall()) {
struct compat_sock_fprog fprog32;
if (copy_from_user(&fprog32, user_filter, sizeof(fprog32)))
goto out;
@@ -529,7 +529,7 @@ static void __secure_computing_strict(int this_syscall)
{
int *syscall_whitelist = mode1_syscalls;
#ifdef CONFIG_COMPAT
- if (is_compat_task())
+ if (in_compat_syscall())
syscall_whitelist = mode1_syscalls_32;
#endif
do {
--
2.5.0