From: Ignat Korchagin ignat@cloudflare.com
[ 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.
Suggested-by: Eric Dumazet edumazet@google.com 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 --- net/packet/af_packet.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index d1ae1d9133d30..dd38cf0c9040d 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3384,18 +3384,18 @@ 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; @@ -3428,7 +3428,7 @@ 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;