From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-4009650-1520451600-2-2700172043797989572 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1520451599; b=PAVOqYNxL56e33Hmc9CqsVHSVOPpnWjMVOU1YXcki/a8/gz i4mDtdmKe2XF6eaHfEEEvjq7o8hvMLBPyotuy6ud++lFrE1bTvevSShKHS+8iBoG nwXXIzz1j83U32qNT9Oqvoo/jwitc+ONRHXiZFgnad8yREu/G8kAFIw6qf52GXzD qTQrMkJAc4cF/EAJexsO7hU3M2A6RhkQ6eTrkayZ0UYUtr9GrxlMF65w6XBgL7R8 25VXplEwXr3ZKRDPk//2azx5SpSmFJSBYDIEtzPV/YF+qgjEuEJI4fa4sTjVzLVw inuFwKoVfo21gFz2kkobozTHiUOZ9bTKxdy9TrQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=arctest; t=1520451599; bh=Ow1stb4kTiPPoQ17vp88lqY/Np H0Oz5k1Jt9ZJaJUbg=; b=fI/WcdJP7KJj5SdbTgGsRwRxIcIGq0rZhvG2ItiM1F NYQ/QFxxoDnXU831a9YI1As/Ye/pE1nJWDd88SDZrG9Ljc/Q9CL6qDtbJUKXHpxw y/OWz13ZtZFfOf6+8ihA3PczWzW4a3eJpTIq6FPR0qPDHd+rJuBi+LLUYI7EaI9C NWUmc3FeQWVsnRWatypMOvF2GREnL2kflxoDVYd1O3jU2chY/PGlgDU2S8iDvaJk eaOFl67+Oqwccy1ILzMZ2L3/Fekad3Cok2QKZx2Be+rztYOSE+SmBMA3FGolVnFh XSx1XLQsTVWcbt/WoHnndn3+j8pw9PphpRzFRoR8m5SA== ARC-Authentication-Results: i=1; mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-category=clean score=-100 state=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933935AbeCGTjy (ORCPT ); Wed, 7 Mar 2018 14:39:54 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:40380 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934169AbeCGTjw (ORCPT ); Wed, 7 Mar 2018 14:39:52 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Richard Fitzgerald , Takashi Iwai Subject: [PATCH 4.15 014/122] ALSA: control: Fix memory corruption risk in snd_ctl_elem_read Date: Wed, 7 Mar 2018 11:37:06 -0800 Message-Id: <20180307191731.293936119@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180307191729.190879024@linuxfoundation.org> References: <20180307191729.190879024@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Richard Fitzgerald commit 5a23699a39abc5328921a81b89383d088f6ba9cc upstream. The patch "ALSA: control: code refactoring for ELEM_READ/ELEM_WRITE operations" introduced a potential for kernel memory corruption due to an incorrect if statement allowing non-readable controls to fall through and call the get function. For TLV controls a driver can omit SNDRV_CTL_ELEM_ACCESS_READ to ensure that only the TLV get function can be called. Instead the normal get() can be invoked unexpectedly and as the driver expects that this will only be called for controls <= 512 bytes, potentially try to copy >512 bytes into the 512 byte return array, so corrupting kernel memory. The problem is an attempt to refactor the snd_ctl_elem_read function to invert the logic so that it conditionally aborted if the control is unreadable instead of conditionally executing. But the if statement wasn't inverted correctly. The correct inversion of if (a && !b) is if (!a || b) Fixes: becf9e5d553c2 ("ALSA: control: code refactoring for ELEM_READ/ELEM_WRITE operations") Signed-off-by: Richard Fitzgerald Cc: Signed-off-by: Takashi Iwai Signed-off-by: Greg Kroah-Hartman --- sound/core/control.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/sound/core/control.c +++ b/sound/core/control.c @@ -888,7 +888,7 @@ static int snd_ctl_elem_read(struct snd_ index_offset = snd_ctl_get_ioff(kctl, &control->id); vd = &kctl->vd[index_offset]; - if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) && kctl->get == NULL) + if (!(vd->access & SNDRV_CTL_ELEM_ACCESS_READ) || kctl->get == NULL) return -EPERM; snd_ctl_build_ioff(&control->id, kctl, index_offset);