From 5e52fffbb11c28c37fe8e335fdd8e9705daff06d Mon Sep 17 00:00:00 2001 From: Jamie Bainbridge Date: Wed, 26 Apr 2017 10:43:27 +1000 Subject: [PATCH] ipv6: check raw payload size correctly in ioctl [ Upstream commit 105f5528b9bbaa08b526d3405a5bcd2ff0c953c8 ] In situations where an skb is paged, the transport header pointer and tail pointer can be the same because the skb contents are in frags. This results in ioctl(SIOCINQ/FIONREAD) incorrectly returning a length of 0 when the length to receive is actually greater than zero. skb->len is already correctly set in ip6_input_finish() with pskb_pull(), so use skb->len as it always returns the correct result for both linear and paged data. Signed-off-by: Jamie Bainbridge Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/raw.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c index 8bca90d6d915..a625f69a28dd 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -1144,8 +1144,7 @@ static int rawv6_ioctl(struct sock *sk, int cmd, unsigned long arg) spin_lock_bh(&sk->sk_receive_queue.lock); skb = skb_peek(&sk->sk_receive_queue); if (skb) - amount = skb_tail_pointer(skb) - - skb_transport_header(skb); + amount = skb->len; spin_unlock_bh(&sk->sk_receive_queue.lock); return put_user(amount, (int __user *)arg); } -- 2.20.1