[PATCH 5.10 123/154] tipc: check for null after calling kmemdup

[Greg Kroah-Hartman]

From: Tadeusz Struk <tadeusz.struk@xxxxxxxxxx>

commit 3e6db079751afd527bf3db32314ae938dc571916 upstream.

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: tipc-discussion@xxxxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx # 5.15, 5.14, 5.10

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

Reported-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: Tadeusz Struk <tadeusz.struk@xxxxxxxxxx>
Acked-by: Ying Xue <ying.xue@xxxxxxxxxxxxx>
Acked-by: Jon Maloy <jmaloy@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20211115160143.5099-1-tadeusz.struk@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/tipc/crypto.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/net/tipc/crypto.c
+++ b/net/tipc/crypto.c
@@ -590,6 +590,10 @@ static int tipc_aead_init(struct tipc_ae
 	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);