From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753939AbaELBnQ (ORCPT ); Sun, 11 May 2014 21:43:16 -0400 Received: from 1wt.eu ([62.212.114.60]:34699 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753884AbaELBnO (ORCPT ); Sun, 11 May 2014 21:43:14 -0400 Message-Id: <20140512003202.712288837@1wt.eu> User-Agent: quilt/0.48-1 Date: Mon, 12 May 2014 02:32:50 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Daniel Borkmann , "David S. Miller" , Willy Tarreau Subject: [ 050/143] packet: packet_getname_spkt: make sure string is always 0-terminated In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Borkmann [ Upstream commit 2dc85bf323515e59e15dfa858d1472bb25cad0fe ] uaddr->sa_data is exactly of size 14, which is hard-coded here and passed as a size argument to strncpy(). A device name can be of size IFNAMSIZ (== 16), meaning we might leave the destination string unterminated. Thus, use strlcpy() and also sizeof() while we're at it. We need to memset the data area beforehand, since strlcpy does not padd the remaining buffer with zeroes for user space, so that we do not possibly leak anything. Signed-off-by: Daniel Borkmann Signed-off-by: David S. Miller Signed-off-by: Willy Tarreau --- net/packet/af_packet.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 728c080..f084e01 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1525,12 +1525,12 @@ static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr, return -EOPNOTSUPP; uaddr->sa_family = AF_PACKET; + memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data)); dev = dev_get_by_index(sock_net(sk), pkt_sk(sk)->ifindex); if (dev) { - strncpy(uaddr->sa_data, dev->name, 14); + strlcpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data)); dev_put(dev); - } else - memset(uaddr->sa_data, 0, 14); + } *uaddr_len = sizeof(*uaddr); return 0; -- 1.7.12.2.21.g234cd45.dirty