| Message ID | 20180930183339.153681-1-edumazet@google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] ipv4: fix use-after-free in ip_cmsg_recv_dstaddr() | expand |
On Sun, Sep 30, 2018 at 2:37 PM Eric Dumazet <edumazet@google.com> wrote: > > Caching ip_hdr(skb) before a call to pskb_may_pull() is buggy, > do not do it. > > Fixes: 2efd4fca703a ("ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Cc: Willem de Bruijn <willemb@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: Willem de Bruijn <willemb@google.com> Argh, indeed. Thanks for fixing this, Eric.
From: Eric Dumazet <edumazet@google.com> Date: Sun, 30 Sep 2018 11:33:39 -0700 > Caching ip_hdr(skb) before a call to pskb_may_pull() is buggy, > do not do it. > > Fixes: 2efd4fca703a ("ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Cc: Willem de Bruijn <willemb@google.com> > Reported-by: syzbot <syzkaller@googlegroups.com> Applied and queued up for -stable.
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index c0fe5ad996f238091f5b9585adb586a571f653f0..26c36cccabdc2c8cc95cfd609672d412c493fc42 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -149,7 +149,6 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb) static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb) { struct sockaddr_in sin; - const struct iphdr *iph = ip_hdr(skb); __be16 *ports; int end; @@ -164,7 +163,7 @@ static void ip_cmsg_recv_dstaddr(struct msghdr *msg, struct sk_buff *skb) ports = (__be16 *)skb_transport_header(skb); sin.sin_family = AF_INET; - sin.sin_addr.s_addr = iph->daddr; + sin.sin_addr.s_addr = ip_hdr(skb)->daddr; sin.sin_port = ports[1]; memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
Caching ip_hdr(skb) before a call to pskb_may_pull() is buggy, do not do it. Fixes: 2efd4fca703a ("ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> --- net/ipv4/ip_sockglue.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)