Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

Pull security layer fixes from James Morris:
 "The keys patch fixes a bug which is breaking kerberos, and the seccomp
  fix addresses a no_new_privs bypass"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  KEYS: Only apply KEY_FLAG_KEEP to a key if a parent keyring has it set
  seccomp: always propagate NO_NEW_PRIVS on tsync

2 files changed, 13 insertions, 12 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);
-		}
 	}
 }
 
diff --git a/security/keys/key.c b/security/keys/key.c
index 07a87311055c..09ef276c4bdc 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -430,7 +430,8 @@ static int __key_instantiate_and_link(struct key *key,
 
 			/* and link it into the destination keyring */
 			if (keyring) {
-				set_bit(KEY_FLAG_KEEP, &key->flags);
+				if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
+					set_bit(KEY_FLAG_KEEP, &key->flags);
 
 				__key_link(key, _edit);
 			}