| Message ID | 20241014153808.51894-4-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 16:38:02 +0100 > bt_sock_alloc() attaches allocated sk object to the provided sock object. > If rfcomm_dlc_alloc() fails, we release the sk object, but leave the > dangling pointer in the sock object, which may cause use-after-free. > > Fix this by swapping calls to bt_sock_alloc() and rfcomm_dlc_alloc(). > > Signed-off-by: Ignat Korchagin <ignat@cloudflare.com> Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
On Mon, Oct 14, 2024 at 11:30 PM Kuniyuki Iwashima <kuniyu@amazon.com> wrote: > > From: Ignat Korchagin <ignat@cloudflare.com> > Date: Mon, 14 Oct 2024 16:38:02 +0100 > > bt_sock_alloc() attaches allocated sk object to the provided sock object. > > If rfcomm_dlc_alloc() fails, we release the sk object, but leave the > > dangling pointer in the sock object, which may cause use-after-free. > > > > Fix this by swapping calls to bt_sock_alloc() and rfcomm_dlc_alloc(). > > > > 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/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c index f48250e3f2e1..355e1a1698f5 100644 --- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -274,13 +274,13 @@ static struct sock *rfcomm_sock_alloc(struct net *net, struct socket *sock, struct rfcomm_dlc *d; struct sock *sk; - sk = bt_sock_alloc(net, sock, &rfcomm_proto, proto, prio, kern); - if (!sk) + d = rfcomm_dlc_alloc(prio); + if (!d) return NULL; - d = rfcomm_dlc_alloc(prio); - if (!d) { - sk_free(sk); + sk = bt_sock_alloc(net, sock, &rfcomm_proto, proto, prio, kern); + if (!sk) { + rfcomm_dlc_free(d); return NULL; }
bt_sock_alloc() attaches allocated sk object to the provided sock object. If rfcomm_dlc_alloc() fails, we release the sk object, but leave the dangling pointer in the sock object, which may cause use-after-free. Fix this by swapping calls to bt_sock_alloc() and rfcomm_dlc_alloc(). Signed-off-by: Ignat Korchagin <ignat@cloudflare.com> --- net/bluetooth/rfcomm/sock.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)