linux-kernel - [PATCH AUTOSEL 6.1 20/48] net: inet: do not leave a dangling sk pointer in inet

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Message-ID: <20241124134950.3348099-20-sashal@kernel.org>
Date: Sun, 24 Nov 2024 08:48:43 -0500
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Ignat Korchagin <ignat@...udflare.com>,
	Kuniyuki Iwashima <kuniyu@...zon.com>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Sasha Levin <sashal@...nel.org>,
	davem@...emloft.net,
	dsahern@...nel.org,
	pabeni@...hat.com,
	netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 6.1 20/48] net: inet: do not leave a dangling sk pointer in inet_create()

From: Ignat Korchagin <ignat@...udflare.com>

[ Upstream commit 9365fa510c6f82e3aa550a09d0c5c6b44dbc78ff ]

sock_init_data() attaches the allocated sk object to the provided sock
object. If inet_create() fails later, the sk object is freed, but the
sock object retains the dangling pointer, which may create use-after-free
later.

Clear the sk pointer in the sock object on error.

Signed-off-by: Ignat Korchagin <ignat@...udflare.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@...zon.com>
Reviewed-by: Eric Dumazet <edumazet@...gle.com>
Link: https://patch.msgid.link/20241014153808.51894-7-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/ipv4/af_inet.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index cc013be9b02c4..4f3c932e37ed5 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -371,32 +371,30 @@ static int inet_create(struct net *net, struct socket *sock, int protocol,
 		inet->inet_sport = htons(inet->inet_num);
 		/* Add to protocol hash chains. */
 		err = sk->sk_prot->hash(sk);
-		if (err) {
-			sk_common_release(sk);
-			goto out;
-		}
+		if (err)
+			goto out_sk_release;
 	}
 
 	if (sk->sk_prot->init) {
 		err = sk->sk_prot->init(sk);
-		if (err) {
-			sk_common_release(sk);
-			goto out;
-		}
+		if (err)
+			goto out_sk_release;
 	}
 
 	if (!kern) {
 		err = BPF_CGROUP_RUN_PROG_INET_SOCK(sk);
-		if (err) {
-			sk_common_release(sk);
-			goto out;
-		}
+		if (err)
+			goto out_sk_release;
 	}
 out:
 	return err;
 out_rcu_unlock:
 	rcu_read_unlock();
 	goto out;
+out_sk_release:
+	sk_common_release(sk);
+	sock->sk = NULL;
+	goto out;
 }
 
 
-- 
2.43.0