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| author | Kees Cook <keescook@chromium.org> | 2015-02-17 22:48:00 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-17 23:34:55 +0100 |
| commit | 580c57f1076872ebc2427f898b927944ce170f2d (patch) | |
| tree | ae0b2110dbe5eeaf98778001bb1d320797c84140 | |
| parent | samples/seccomp: improve label helper (diff) | |
| download | linux-580c57f1076872ebc2427f898b927944ce170f2d.tar.xz linux-580c57f1076872ebc2427f898b927944ce170f2d.zip | |
seccomp: cap SECCOMP_RET_ERRNO data to MAX_ERRNO
The value resulting from the SECCOMP_RET_DATA mask could exceed MAX_ERRNO
when setting errno during a SECCOMP_RET_ERRNO filter action. This makes
sure we have a reliable value being set, so that an invalid errno will not
be ignored by userspace.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Dmitry V. Levin <ldv@altlinux.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/seccomp.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 4ef9687ac115..4f44028943e6 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -629,7 +629,9 @@ static u32 __seccomp_phase1_filter(int this_syscall, struct seccomp_data *sd) switch (action) { case SECCOMP_RET_ERRNO: - /* Set the low-order 16-bits as a errno. */ + /* Set low-order bits as an errno, capped at MAX_ERRNO. */ + if (data > MAX_ERRNO) + data = MAX_ERRNO; syscall_set_return_value(current, task_pt_regs(current), -data, 0); goto skip; |