diff options
author | Jann Horn <jann@thejh.net> | 2015-12-26 05:00:48 (GMT) |
---|---|---|
committer | Kees Cook <keescook@chromium.org> | 2016-01-27 15:38:25 (GMT) |
commit | 103502a35cfce0710909da874f092cb44823ca03 (patch) | |
tree | 81f6474629fba8af0fc696d5944711f312e04fa0 /kernel | |
parent | 607259e17b37017e9ec0249a8b0a7d8b76b572aa (diff) | |
download | linux-103502a35cfce0710909da874f092cb44823ca03.tar.xz |
seccomp: always propagate NO_NEW_PRIVS on tsync
Before this patch, a process with some permissive seccomp filter
that was applied by root without NO_NEW_PRIVS was able to add
more filters to itself without setting NO_NEW_PRIVS by setting
the new filter from a throwaway thread with NO_NEW_PRIVS.
Signed-off-by: Jann Horn <jann@thejh.net>
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/seccomp.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 580ac2d..15a1795 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -316,24 +316,24 @@ static inline void seccomp_sync_threads(void) put_seccomp_filter(thread); smp_store_release(&thread->seccomp.filter, caller->seccomp.filter); + + /* + * Don't let an unprivileged task work around + * the no_new_privs restriction by creating + * a thread that sets it up, enters seccomp, + * then dies. + */ + if (task_no_new_privs(caller)) + task_set_no_new_privs(thread); + /* * Opt the other thread into seccomp if needed. * As threads are considered to be trust-realm * equivalent (see ptrace_may_access), it is safe to * allow one thread to transition the other. */ - if (thread->seccomp.mode == SECCOMP_MODE_DISABLED) { - /* - * Don't let an unprivileged task work around - * the no_new_privs restriction by creating - * a thread that sets it up, enters seccomp, - * then dies. - */ - if (task_no_new_privs(caller)) - task_set_no_new_privs(thread); - + if (thread->seccomp.mode == SECCOMP_MODE_DISABLED) seccomp_assign_mode(thread, SECCOMP_MODE_FILTER); - } } } |