From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Bainbridge Subject: [PATCH 1/2] ipv6: check raw payload size correctly in ioctl Date: Fri, 21 Apr 2017 13:58:43 +1000 Message-ID: <1492747124-31821-1-git-send-email-jbainbri@redhat.com> Cc: Jamie Bainbridge To: "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , Patrick McHardy , netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:38982 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1034978AbdDUD7A (ORCPT ); Thu, 20 Apr 2017 23:59:00 -0400 Sender: netdev-owner@vger.kernel.org List-ID: In situations where an skb is paged, the transport header pointer and tail pointer will be the same because the payload is in skb frags. This results in ioctl(SIOCINQ/FIONREAD) 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 --- 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 f174e76e6505d4045e940c9fceef765d2aaa937d..0da6a12b5472e322d679572c7244e5c9bc467741 100644 --- a/net/ipv6/raw.c +++ b/net/ipv6/raw.c @@ -1178,8 +1178,7 @@ 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); } -- 1.8.3.1