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authorJann Horn <jann@thejh.net>2015-12-26 06:00:48 +0100
committerSasha Levin <sasha.levin@oracle.com>2016-02-15 15:42:33 -0500
commit4702c50cfaecb5a4daa40b6d2b10983b8f2fc8e6 (patch)
treeff28aaec30a3fb3c5deb3607c672117df8bbf35b /kernel
parentd71046b5dfe38d4954142e5117a66bc54e40116b (diff)
downloadlinux-linaro-stable-4702c50cfaecb5a4daa40b6d2b10983b8f2fc8e6.tar.gz
seccomp: always propagate NO_NEW_PRIVS on tsync
[ Upstream commit 103502a35cfce0710909da874f092cb44823ca03 ] 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> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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 4ef9687ac115..a39025b02fd5 100644
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -317,24 +317,24 @@ 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);
- }
}
}