[PATCH v2] tipc: check for null after calling kmemdup

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 <redacted>
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 <redacted>
---
Changed in v2:
- use tipc_aead_free() to free all crytpo tfm instances
  that might have been allocated before the fail.
---
 net/tipc/crypto.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c
index dc60c32bb70d..d293614d5fc6 100644
--- a/net/tipc/crypto.c
+++ b/net/tipc/crypto.c

@@ -597,6 +597,10 @@ 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) {
+		tipc_aead_free(&tmp->rcu);
+		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

Acked-by: Ying Xue <redacted>

-----Original Message-----
From: Tadeusz Struk <redacted> 
Sent: Tuesday, November 16, 2021 12:02 AM
To: davem@davemloft.net
Cc: Tadeusz Struk <redacted>; Jon Maloy <jmaloy@redhat.com>; Xue, Ying <redacted>; 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 v2] tipc: check for null after calling kmemdup

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 <redacted>
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 <redacted>
---
Changed in v2:
- use tipc_aead_free() to free all crytpo tfm instances
  that might have been allocated before the fail.
---
 net/tipc/crypto.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/tipc/crypto.c b/net/tipc/crypto.c index dc60c32bb70d..d293614d5fc6 100644
--- a/net/tipc/crypto.c
+++ b/net/tipc/crypto.c

@@ -597,6 +597,10 @@ 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) {
+		tipc_aead_free(&tmp->rcu);
+		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

Acked-by: Jon Maloy <jmaloy@redhat.com>

On 11/15/21 11:01, Tadeusz Struk wrote:

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski [off-list ref]:

On Mon, 15 Nov 2021 08:01:43 -0800 you wrote:

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 <redacted>
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

[...]

Here is the summary with links:
  - [v2] tipc: check for null after calling kmemdup
    https://git.kernel.org/netdev/net/c/3e6db079751a

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html