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authorKees Cook <keescook@chromium.org>2015-02-17 13:48:00 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-17 14:34:55 -0800
commit580c57f1076872ebc2427f898b927944ce170f2d (patch)
treeae0b2110dbe5eeaf98778001bb1d320797c84140 /kernel
parentsamples/seccomp: improve label helper (diff)
downloadlinux-dev-580c57f1076872ebc2427f898b927944ce170f2d.tar.xz
linux-dev-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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/seccomp.c4
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;