From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946513Ab2I1VzB (ORCPT ); Fri, 28 Sep 2012 17:55:01 -0400 Received: from mail-da0-f46.google.com ([209.85.210.46]:46787 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1032004Ab2I1UW6 (ORCPT ); Fri, 28 Sep 2012 16:22:58 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Mathias Krause , "David S. Miller" Subject: [ 021/218] net: fix info leak in compat dev_ifconf() Date: Fri, 28 Sep 2012 13:13:58 -0700 Message-Id: <20120928201503.787804645@linuxfoundation.org> X-Mailer: git-send-email 1.7.12.1.428.g652398a In-Reply-To: <20120928201501.208384923@linuxfoundation.org> References: <20120928201501.208384923@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 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mathias Krause [ Upstream commit 43da5f2e0d0c69ded3d51907d9552310a6b545e8 ] The implementation of dev_ifconf() for the compat ioctl interface uses an intermediate ifc structure allocated in userland for the duration of the syscall. Though, it fails to initialize the padding bytes inserted for alignment and that for leaks four bytes of kernel stack. Add an explicit memset(0) before filling the structure to avoid the info leak. Signed-off-by: Mathias Krause Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/socket.c | 1 + 1 file changed, 1 insertion(+) --- a/net/socket.c +++ b/net/socket.c @@ -2658,6 +2658,7 @@ static int dev_ifconf(struct net *net, s if (copy_from_user(&ifc32, uifc32, sizeof(struct compat_ifconf))) return -EFAULT; + memset(&ifc, 0, sizeof(ifc)); if (ifc32.ifcbuf == 0) { ifc32.ifc_len = 0; ifc.ifc_len = 0;