From e8c99200b4d117c340c392ebd5e62d85dfeed027 Mon Sep 17 00:00:00 2001 From: Jia-Ju Bai Date: Wed, 24 Jul 2019 17:43:06 +0800 Subject: [PATCH] libceph: don't call crypto_free_sync_skcipher() on a NULL tfm In set_secret(), key->tfm is assigned to NULL on line 55, and then ceph_crypto_key_destroy(key) is executed. ceph_crypto_key_destroy(key) crypto_free_sync_skcipher(key->tfm) crypto_free_skcipher(&tfm->base); This happens to work because crypto_sync_skcipher is a trivial wrapper around crypto_skcipher: &tfm->base is still 0 and crypto_free_skcipher() handles that. Let's not rely on the layout of crypto_sync_skcipher. This bug is found by a static analysis tool STCheck written by us. Fixes: 69d6302b65a8 ("libceph: Remove VLA usage of skcipher"). Signed-off-by: Jia-Ju Bai Reviewed-by: Ilya Dryomov Signed-off-by: Ilya Dryomov --- net/ceph/crypto.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/ceph/crypto.c b/net/ceph/crypto.c index 5d6724c..4f75df4 100644 --- a/net/ceph/crypto.c +++ b/net/ceph/crypto.c @@ -136,8 +136,10 @@ void ceph_crypto_key_destroy(struct ceph_crypto_key *key) if (key) { kfree(key->key); key->key = NULL; - crypto_free_sync_skcipher(key->tfm); - key->tfm = NULL; + if (key->tfm) { + crypto_free_sync_skcipher(key->tfm); + key->tfm = NULL; + } } } -- 2.7.4