From:   Tadeusz Struk <tadeusz.struk@linaro.org>
To:     jmaloy@redhat.com
Cc:     Tadeusz Struk <tadeusz.struk@linaro.org>,
        Ying Xue <ying.xue@windriver.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        tipc-discussion@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, stable@vger.kernel.org,
        Dmitry Vyukov <dvyukov@google.com>
Subject: [PATCH] tipc: check for null after calling kmemdup
Date:   Thu, 11 Nov 2021 12:59:15 -0800
Message-Id: <20211111205916.37899-1-tadeusz.struk@linaro.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

kmemdup can return a null pointer so need to check for it, otherwise
the null key will be dereferenced later in tipc_crypto_key_xmit as
can be seen in the trace [1].

Cc: Jon Maloy <jmaloy@redhat.com>
Cc: Ying Xue <ying.xue@windriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Cc: tipc-discussion@lists.sourceforge.net
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # 5.15, 5.14, 5.10

[1] https://syzkaller.appspot.com/bug?id=bca180abb29567b189efdbdb34cbf7ba851c2a58

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
---
 net/tipc/crypto.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
index dc60c32bb70d..988a343f9fd5 100644
--- a/net/tipc/crypto.c
+++ b/net/tipc/crypto.c
@@ -597,6 +597,11 @@ static int tipc_aead_init(struct tipc_aead **aead, struct tipc_aead_key *ukey,
 	tmp->cloned = NULL;
 	tmp->authsize = TIPC_AES_GCM_TAG_SIZE;
 	tmp->key = kmemdup(ukey, tipc_aead_key_size(ukey), GFP_KERNEL);
+	if (!tmp->key) {
+		free_percpu(tmp->tfm_entry);
+		kfree_sensitive(tmp);
+		return -ENOMEM;
+	}
 	memcpy(&tmp->salt, ukey->key + keylen, TIPC_AES_GCM_SALT_SIZE);
 	atomic_set(&tmp->users, 0);
 	atomic64_set(&tmp->seqno, 0);
-- 
2.33.1