The latest change of compat_sys_sigpending in commit 8f13621abced ("sigpending(): move compat to native") has broken it in two ways. First, it tries to write 4 bytes more than userspace expects: sizeof(old_sigset_t) == sizeof(long) == 8 instead of sizeof(compat_old_sigset_t) == sizeof(u32) == 4. Second, on big endian architectures these bytes are being written in the wrong order. This bug was found by strace test suite.
Unified · Split
| @@ -3303,12 +3303,15 @@ SYSCALL_DEFINE1(sigpending, old_sigset_t __user *, set) · 3302 unmodified lines | |||
| 3303 | #ifdef CONFIG_COMPAT | 3303 | #ifdef CONFIG_COMPAT |
| 3304 | COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32) | 3304 | COMPAT_SYSCALL_DEFINE1(sigpending, compat_old_sigset_t __user *, set32) |
| 3305 | { | 3305 | { |
| 3306 | #ifdef __BIG_ENDIAN | ||
| 3306 | sigset_t set; | 3307 | sigset_t set; |
| 3307 | int err = do_sigpending(&set, sizeof(old_sigset_t)); | 3308 | int err = do_sigpending(&set, sizeof(set.sig[0])); |
| 3308 | if (err == 0) | 3309 | if (!err) |
| 3309 | if (copy_to_user(set32, &set, sizeof(old_sigset_t))) | 3310 | err = put_user(set.sig[0], set32); |
| 3310 | err = -EFAULT; | ||
| 3311 | return err; | 3311 | return err; |
| 3312 | #else | ||
| 3313 | return sys_rt_sigpending((sigset_t __user *)set32, sizeof(*set32)); | ||
| 3314 | #endif | ||
| 3312 | } | 3315 | } |
| 3313 | #endif | 3316 | #endif |
| 3314 | 3317 | ||