| Message ID | 20241014153808.51894-8-ignat@cloudflare.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | do not leave dangling sk pointers in pf->create functions | expand |
From: Ignat Korchagin <ignat@cloudflare.com> Date: Mon, 14 Oct 2024 16:38:06 +0100 > sock_init_data() attaches the allocated sk pointer to the provided sock > object. If inet6_create() fails later, the sk object is released, but the > sock object retains the dangling sk pointer, which may cause use-after-free > later. > > Clear the sock sk pointer on error. > > Signed-off-by: Ignat Korchagin <ignat@cloudflare.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
On Mon, Oct 14, 2024 at 11:39 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote: > > From: Ignat Korchagin <ignat@cloudflare.com> > Date: Mon, 14 Oct 2024 16:38:06 +0100 > > sock_init_data() attaches the allocated sk pointer to the provided sock > > object. If inet6_create() fails later, the sk object is released, but the > > sock object retains the dangling sk pointer, which may cause use-after-free > > later. > > > > Clear the sock sk pointer on error. > > > > Signed-off-by: Ignat Korchagin <ignat@cloudflare.com> > > Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: Eric Dumazet <edumazet@google.com>
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c index ba69b86f1c7d..f60ec8b0f8ea 100644 --- a/net/ipv6/af_inet6.c +++ b/net/ipv6/af_inet6.c @@ -252,31 +252,29 @@ static int inet6_create(struct net *net, struct socket *sock, int protocol, */ inet->inet_sport = htons(inet->inet_num); 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; } static int __inet6_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
sock_init_data() attaches the allocated sk pointer to the provided sock object. If inet6_create() fails later, the sk object is released, but the sock object retains the dangling sk pointer, which may cause use-after-free later. Clear the sock sk pointer on error. Signed-off-by: Ignat Korchagin <ignat@cloudflare.com> --- net/ipv6/af_inet6.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-)