[PATCH 3.18 058/145] dccp: fix freeing skb too early for IPV6_RECVPKTINFO
From: Greg Kroah-Hartman
Date: Sun Apr 16 2017 - 06:54:09 EST
3.18-stable review patch. If anyone has any objections, please let me know.
------------------
From: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
[ Upstream commit 5edabca9d4cff7f1f2b68f0bac55ef99d9798ba4 ]
In the current DCCP implementation an skb for a DCCP_PKT_REQUEST packet
is forcibly freed via __kfree_skb in dccp_rcv_state_process if
dccp_v6_conn_request successfully returns.
However, if IPV6_RECVPKTINFO is set on a socket, the address of the skb
is saved to ireq->pktopts and the ref count for skb is incremented in
dccp_v6_conn_request, so skb is still in use. Nevertheless, it gets freed
in dccp_rcv_state_process.
Fix by calling consume_skb instead of doing goto discard and therefore
calling __kfree_skb.
Similar fixes for TCP:
fb7e2399ec17f1004c0e0ccfd17439f8759ede01 [TCP]: skb is unexpectedly freed.
0aea76d35c9651d55bbaf746e7914e5f9ae5a25d tcp: SYN packets are now
simply consumed
Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/dccp/input.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -606,7 +606,8 @@ int dccp_rcv_state_process(struct sock *
if (inet_csk(sk)->icsk_af_ops->conn_request(sk,
skb) < 0)
return 1;
- goto discard;
+ consume_skb(skb);
+ return 0;
}
if (dh->dccph_type == DCCP_PKT_RESET)
goto discard;