From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754807Ab1AFAgU (ORCPT ); Wed, 5 Jan 2011 19:36:20 -0500 Received: from kroah.org ([198.145.64.141]:36090 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754755Ab1AFAbn (ORCPT ); Wed, 5 Jan 2011 19:31:43 -0500 X-Mailbox-Line: From gregkh@clark.site Wed Jan 5 16:23:09 2011 Message-Id: <20110106002309.434980933@clark.site> User-Agent: quilt/0.48-11.2 Date: Wed, 05 Jan 2011 16:23:54 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Dan Rosenberg , Takashi Iwai Subject: [135/152] sound: Prevent buffer overflow in OSS load_mixer_volumes In-Reply-To: <20110106002500.GA3172@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.36-stable review patch. If anyone has any objections, please let us know. ------------------ From: Dan Rosenberg commit d81a12bc29ae4038770e05dce4ab7f26fd5880fb upstream. The load_mixer_volumes() function, which can be triggered by unprivileged users via the SOUND_MIXER_SETLEVELS ioctl, is vulnerable to a buffer overflow. Because the provided "name" argument isn't guaranteed to be NULL terminated at the expected 32 bytes, it's possible to overflow past the end of the last element in the mixer_vols array. Further exploitation can result in an arbitrary kernel write (via subsequent calls to load_mixer_volumes()) leading to privilege escalation, or arbitrary kernel reads via get_mixer_levels(). In addition, the strcmp() may leak bytes beyond the mixer_vols array. Signed-off-by: Dan Rosenberg Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/oss/soundcard.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/sound/oss/soundcard.c +++ b/sound/oss/soundcard.c @@ -86,7 +86,7 @@ int *load_mixer_volumes(char *name, int int i, n; for (i = 0; i < num_mixer_volumes; i++) { - if (strcmp(name, mixer_vols[i].name) == 0) { + if (strncmp(name, mixer_vols[i].name, 32) == 0) { if (present) mixer_vols[i].num = i; return mixer_vols[i].levels; @@ -98,7 +98,7 @@ int *load_mixer_volumes(char *name, int } n = num_mixer_volumes++; - strcpy(mixer_vols[n].name, name); + strncpy(mixer_vols[n].name, name, 32); if (present) mixer_vols[n].num = n;