From: Eric Biggers <ebiggers@xxxxxxxxxx> It is a bug for fscrypt_put_master_key_activeref() to see a NULL keyring. But it used to be possible due to the bug, now fixed, where fscrypt_destroy_keyring() was called before security_sb_delete(). To be consistent with how fscrypt_destroy_keyring() uses WARN_ON for the same issue, WARN and leak the fscrypt_master_key if the keyring is NULL instead of dereferencing the NULL pointer. This is a robustness improvement, not a fix. Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx> --- fs/crypto/keyring.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/crypto/keyring.c b/fs/crypto/keyring.c index bb15709ac9a40..13d336a6cc5da 100644 --- a/fs/crypto/keyring.c +++ b/fs/crypto/keyring.c @@ -92,6 +92,8 @@ void fscrypt_put_master_key_activeref(struct super_block *sb, * destroying any subkeys embedded in it. */ + if (WARN_ON(!sb->s_master_keys)) + return; spin_lock(&sb->s_master_keys->lock); hlist_del_rcu(&mk->mk_node); spin_unlock(&sb->s_master_keys->lock); -- 2.39.2
