Commit 580c57f1 authored by Kees Cook's avatar Kees Cook Committed by Linus Torvalds
Browse files

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: default avatarKees Cook <keescook@chromium.org>
Reported-by: default avatarDmitry V. Levin <ldv@altlinux.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Will Drewry <wad@chromium.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3a9af0bd
......@@ -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;
......
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