| Message ID | 20241014153808.51894-7-ignat@cloudflare.com |
|---|---|
| State | Accepted |
| Commit | 9365fa510c6f82e3aa550a09d0c5c6b44dbc78ff |
| 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 16:38:05 +0100 > 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>
On Mon, Oct 14, 2024 at 11:37 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote: > > From: Ignat Korchagin <ignat@cloudflare.com> > Date: Mon, 14 Oct 2024 16:38:05 +0100 > > 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>
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index b24d74616637..8095e82de808 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -376,32 +376,30 @@ 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; }
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> --- net/ipv4/af_inet.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-)