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authorJann Horn2015-12-26 06:00:48 +0100
committerKees Cook2016-01-27 07:38:25 -0800
commit103502a35cfce0710909da874f092cb44823ca03 (patch)
tree81f6474629fba8af0fc696d5944711f312e04fa0 /kernel
parent607259e17b37017e9ec0249a8b0a7d8b76b572aa (diff)
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.c22
1 files changed, 11 insertions, 11 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 580ac2d4024f..15a1795bbba1 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);
- }
}
}