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ipv6: tcp: add a missing tcp_v6_restore_cb() 

Dmitry reported use-after-free in ip6_datagram_recv_specific_ctl()

A similar bug was fixed in commit 8ce48623f0 ("ipv6: tcp: restore
IP6CB for pktoptions skbs"), but I missed another spot.

tcp_v6_syn_recv_sock() can indeed set np->pktoptions from ireq->pktopts

Fixes: 971f10eca1 ("tcp: better TCP_SKB_CB layout to reduce cache line misses")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2017-02-05 20:23:22 -08:00 committed by David S. Miller
parent 7892032cfe
commit ebf6c9cb23
1 changed files with 13 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
net/ipv6/tcp_ipv6.c
View File

@ -991,6 +991,16 @@ drop:
return 0; /* don't send reset */
}
static void tcp_v6_restore_cb(struct sk_buff *skb)
{
/* We need to move header back to the beginning if xfrm6_policy_check()
* and tcp_v6_fill_cb() are going to be called again.
* ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
*/
memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
sizeof(struct inet6_skb_parm));
}
static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *skb,
struct request_sock *req,
struct dst_entry *dst,
@ -1182,8 +1192,10 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff *
sk_gfp_mask(sk, GFP_ATOMIC));
consume_skb(ireq->pktopts);
ireq->pktopts = NULL;
if (newnp->pktoptions)
if (newnp->pktoptions) {
tcp_v6_restore_cb(newnp->pktoptions);
skb_set_owner_r(newnp->pktoptions, newsk);
}
}
}
@ -1198,16 +1210,6 @@ out:
return NULL;
}
static void tcp_v6_restore_cb(struct sk_buff *skb)
{
/* We need to move header back to the beginning if xfrm6_policy_check()
* and tcp_v6_fill_cb() are going to be called again.
* ip6_datagram_recv_specific_ctl() also expects IP6CB to be there.
*/
memmove(IP6CB(skb), &TCP_SKB_CB(skb)->header.h6,
sizeof(struct inet6_skb_parm));
}
/* The socket must have it's spinlock held when we get
* here, unless it is a TCP_LISTEN socket.
*