af_packet: avoid erroring out after sock_init_data() in packet_create()
[ Upstream commit 46f2a11cb82b657fd15bab1c47821b635e03838b ]
After sock_init_data() the allocated sk object is attached to the provided
sock object. On error, packet_create() frees the sk object leaving the
dangling pointer in the sock object on return. Some other code may try
to use this pointer and cause use-after-free.
BUG=b/388762512
TEST=presubmit
RELEASE_NOTE=Fixed CVE-2024-56606 in the Linux kernel.
cos-patch: security-high
Suggested-by: Eric Dumazet <edumazet@google.com>
Change-Id: If5a3dcdf5ff4febd12a1fd08d52e838938fe4283
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241014153808.51894-2-ignat@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kernel CVE Triage Automation <cloud-image-kernel-cve-triage-automation@prod.google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/90043
Reviewed-by: Kevin Berry <kpberry@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Shuo Yang <gshuoy@google.com>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 1806f34..88127df 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -3418,18 +3418,18 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
if (sock->type == SOCK_PACKET)
sock->ops = &packet_ops_spkt;
+ po = pkt_sk(sk);
+ err = packet_alloc_pending(po);
+ if (err)
+ goto out_sk_free;
+
sock_init_data(sock, sk);
- po = pkt_sk(sk);
init_completion(&po->skb_completion);
sk->sk_family = PF_PACKET;
po->num = proto;
po->xmit = dev_queue_xmit;
- err = packet_alloc_pending(po);
- if (err)
- goto out2;
-
packet_cached_dev_reset(po);
sk->sk_destruct = packet_sock_destruct;
@@ -3462,7 +3462,7 @@ static int packet_create(struct net *net, struct socket *sock, int protocol,
sock_prot_inuse_add(net, &packet_proto, 1);
return 0;
-out2:
+out_sk_free:
sk_free(sk);
out:
return err;
