Message ID | 7f2a5122d93d4b72115027690e89c0a164097452.1508333869.git.lucien.xin@gmail.com |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
Series | [net] sctp: add the missing sock_owned_by_user check in sctp_icmp_redirect | expand |
On Wed, Oct 18, 2017 at 09:37:49PM +0800, Xin Long wrote: > Now sctp processes icmp redirect packet in sctp_icmp_redirect where > it calls sctp_transport_dst_check in which tp->dst can be released. > > The problem is before calling sctp_transport_dst_check, it doesn't > check sock_owned_by_user, which means tp->dst could be freed while > a process is accessing it with owning the socket. > > An use-after-free issue could be triggered by this. > > This patch is to fix it by checking sock_owned_by_user before calling > sctp_transport_dst_check in sctp_icmp_redirect, so that it would not > release tp->dst if users still hold sock lock. > > Besides, the same issue fixed in commit 45caeaa5ac0b ("dccp/tcp: fix > routing redirect race") on sctp also needs this check. > > Fixes: 55be7a9c6074 ("ipv4: Add redirect support to all protocol icmp error handlers") > Reported-by: Eric Dumazet <edumazet@google.com> Nice catch, btw. > Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Thanks > --- > net/sctp/input.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/sctp/input.c b/net/sctp/input.c > index 92a0714..34f10e7 100644 > --- a/net/sctp/input.c > +++ b/net/sctp/input.c > @@ -421,7 +421,7 @@ void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, > { > struct dst_entry *dst; > > - if (!t) > + if (sock_owned_by_user(sk) || !t) > return; > dst = sctp_transport_dst_check(t); > if (dst) > -- > 2.1.0 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
On Wed, Oct 18, 2017 at 09:37:49PM +0800, Xin Long wrote: > Now sctp processes icmp redirect packet in sctp_icmp_redirect where > it calls sctp_transport_dst_check in which tp->dst can be released. > > The problem is before calling sctp_transport_dst_check, it doesn't > check sock_owned_by_user, which means tp->dst could be freed while > a process is accessing it with owning the socket. > > An use-after-free issue could be triggered by this. > > This patch is to fix it by checking sock_owned_by_user before calling > sctp_transport_dst_check in sctp_icmp_redirect, so that it would not > release tp->dst if users still hold sock lock. > > Besides, the same issue fixed in commit 45caeaa5ac0b ("dccp/tcp: fix > routing redirect race") on sctp also needs this check. > > Fixes: 55be7a9c6074 ("ipv4: Add redirect support to all protocol icmp error handlers") > Reported-by: Eric Dumazet <edumazet@google.com> > Signed-off-by: Xin Long <lucien.xin@gmail.com> > --- > net/sctp/input.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/sctp/input.c b/net/sctp/input.c > index 92a0714..34f10e7 100644 > --- a/net/sctp/input.c > +++ b/net/sctp/input.c > @@ -421,7 +421,7 @@ void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, > { > struct dst_entry *dst; > > - if (!t) > + if (sock_owned_by_user(sk) || !t) > return; > dst = sctp_transport_dst_check(t); > if (dst) > -- > 2.1.0 > > Acked-by: Neil Horman <nhorman@tuxdriver.com>
From: Xin Long <lucien.xin@gmail.com> Date: Wed, 18 Oct 2017 21:37:49 +0800 > Now sctp processes icmp redirect packet in sctp_icmp_redirect where > it calls sctp_transport_dst_check in which tp->dst can be released. > > The problem is before calling sctp_transport_dst_check, it doesn't > check sock_owned_by_user, which means tp->dst could be freed while > a process is accessing it with owning the socket. > > An use-after-free issue could be triggered by this. > > This patch is to fix it by checking sock_owned_by_user before calling > sctp_transport_dst_check in sctp_icmp_redirect, so that it would not > release tp->dst if users still hold sock lock. > > Besides, the same issue fixed in commit 45caeaa5ac0b ("dccp/tcp: fix > routing redirect race") on sctp also needs this check. > > Fixes: 55be7a9c6074 ("ipv4: Add redirect support to all protocol icmp error handlers") > Reported-by: Eric Dumazet <edumazet@google.com> > Signed-off-by: Xin Long <lucien.xin@gmail.com> Applied and queued up for -stable.
diff --git a/net/sctp/input.c b/net/sctp/input.c index 92a0714..34f10e7 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -421,7 +421,7 @@ void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t, { struct dst_entry *dst; - if (!t) + if (sock_owned_by_user(sk) || !t) return; dst = sctp_transport_dst_check(t); if (dst)
Now sctp processes icmp redirect packet in sctp_icmp_redirect where it calls sctp_transport_dst_check in which tp->dst can be released. The problem is before calling sctp_transport_dst_check, it doesn't check sock_owned_by_user, which means tp->dst could be freed while a process is accessing it with owning the socket. An use-after-free issue could be triggered by this. This patch is to fix it by checking sock_owned_by_user before calling sctp_transport_dst_check in sctp_icmp_redirect, so that it would not release tp->dst if users still hold sock lock. Besides, the same issue fixed in commit 45caeaa5ac0b ("dccp/tcp: fix routing redirect race") on sctp also needs this check. Fixes: 55be7a9c6074 ("ipv4: Add redirect support to all protocol icmp error handlers") Reported-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> --- net/sctp/input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)