[PATCH AUTOSEL 5.10 14/33] net: inet: do not leave a dangling sk pointer in inet_create()

Sasha Levin
2024-11-24T13:54:37Z

From: Ignat Korchagin <ignat@cloudflare.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@cloudflare.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241014153808.51894-7-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.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 58dfca09093c2..c64a52b30ddc9 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -373,32 +373,30 @@ 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