From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 5.2 62/94] libceph: don't call crypto_free_sync_skcipher() on a NULL tfm Date: Wed, 4 Sep 2019 11:57:07 -0400 Message-ID: <20190904155739.2816-62-sashal@kernel.org> References: <20190904155739.2816-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190904155739.2816-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jia-Ju Bai , Ilya Dryomov , Sasha Levin , ceph-devel@vger.kernel.org, netdev@vger.kernel.org List-Id: ceph-devel.vger.kernel.org From: Jia-Ju Bai [ Upstream commit e8c99200b4d117c340c392ebd5e62d85dfeed027 ] 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 Signed-off-by: Sasha Levin --- 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 5d6724cee38f9..4f75df40fb121 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; + } } } -- 2.20.1