From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759418Ab3BLVCN (ORCPT ); Tue, 12 Feb 2013 16:02:13 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:53549 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753769Ab3BLUgB (ORCPT ); Tue, 12 Feb 2013 15:36:01 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Phil Sutter , Johann Baudy , Daniel Borkmann , "David S. Miller" Subject: [ 36/61] packet: fix leakage of tx_ring memory Date: Tue, 12 Feb 2013 12:34:56 -0800 Message-Id: <20130212203423.026242027@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.rc1.5.g7e0651a In-Reply-To: <20130212203417.890993903@linuxfoundation.org> References: <20130212203417.890993903@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Phil Sutter [ Upstream commit 9665d5d62487e8e7b1f546c00e11107155384b9a ] When releasing a packet socket, the routine packet_set_ring() is reused to free rings instead of allocating them. But when calling it for the first time, it fills req->tp_block_nr with the value of rb->pg_vec_len which in the second invocation makes it bail out since req->tp_block_nr is greater zero but req->tp_block_size is zero. This patch solves the problem by passing a zeroed auto-variable to packet_set_ring() upon each invocation from packet_release(). As far as I can tell, this issue exists even since 69e3c75 (net: TX_RING and packet mmap), i.e. the original inclusion of TX ring support into af_packet, but applies only to sockets with both RX and TX ring allocated, which is probably why this was unnoticed all the time. Signed-off-by: Phil Sutter Cc: Johann Baudy Cc: Daniel Borkmann Acked-by: Daniel Borkmann Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2335,13 +2335,15 @@ static int packet_release(struct socket packet_flush_mclist(sk); - memset(&req_u, 0, sizeof(req_u)); - - if (po->rx_ring.pg_vec) + if (po->rx_ring.pg_vec) { + memset(&req_u, 0, sizeof(req_u)); packet_set_ring(sk, &req_u, 1, 0); + } - if (po->tx_ring.pg_vec) + if (po->tx_ring.pg_vec) { + memset(&req_u, 0, sizeof(req_u)); packet_set_ring(sk, &req_u, 1, 1); + } fanout_release(sk);