net: fix skb leak in __skb_tstamp_tx()

stable inclusion
from stable-v4.19.284
commit 779332447108545ef04682ea29af5f85c0202aee
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7J5UF
CVE: NA

--------------------------------

commit 8a02fb71 upstream.

Commit 50749f2d ("tcp/udp: Fix memleaks of sk and zerocopy skbs with
TX timestamp.") added a call to skb_orphan_frags_rx() to fix leaks with
zerocopy skbs. But it ended up adding a leak of its own. When
skb_orphan_frags_rx() fails, the function just returns, leaking the skb
it just cloned. Free it before returning.

This bug was discovered and resolved using Coverity Static Analysis
Security Testing (SAST) by Synopsys, Inc.

Fixes: 50749f2d ("tcp/udp: Fix memleaks of sk and zerocopy skbs with TX timestamp.")
Signed-off-by: NPratyush Yadav <ptyadav@amazon.de>
Reviewed-by: NKuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: NWillem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20230522153020.32422-1-ptyadav@amazon.deSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>

net/core/skbuff.c

@@ -4446,8 +4446,10 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
 	} else {
 		skb = skb_clone(orig_skb, GFP_ATOMIC);
 
-		if (skb_orphan_frags_rx(skb, GFP_ATOMIC))
+		if (skb_orphan_frags_rx(skb, GFP_ATOMIC)) {
+			kfree_skb(skb);
 			return;
+		}
 	}
 	if (!skb)
 		return;