From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754708AbbJ0WDQ (ORCPT ); Tue, 27 Oct 2015 18:03:16 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:34922 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932314AbbJ0VbB (ORCPT ); Tue, 27 Oct 2015 17:31:01 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Luis Henriques , Andrew Morton , Linus Torvalds , Kamal Mostafa Subject: [PATCH 3.19.y-ckt 43/86] zram: fix possible use after free in zcomp_create() Date: Tue, 27 Oct 2015 14:29:43 -0700 Message-Id: <1445981426-19727-44-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1445981426-19727-1-git-send-email-kamal@canonical.com> References: <1445981426-19727-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.19 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.19.8-ckt9 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Luis Henriques commit 3aaf14da807a4e9931a37f21e4251abb8a67021b upstream. zcomp_create() verifies the success of zcomp_strm_{multi,single}_create() through comp->stream, which can potentially be pointing to memory that was freed if these functions returned an error. While at it, replace a 'ERR_PTR(-ENOMEM)' by a more generic 'ERR_PTR(error)' as in the future zcomp_strm_{multi,siggle}_create() could return other error codes. Function documentation updated accordingly. Fixes: beca3ec71fe5 ("zram: add multi stream functionality") Signed-off-by: Luis Henriques Acked-by: Sergey Senozhatsky Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Kamal Mostafa --- drivers/block/zram/zcomp.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index f1ff39a..54d946a 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -325,12 +325,14 @@ void zcomp_destroy(struct zcomp *comp) * allocate new zcomp and initialize it. return compressing * backend pointer or ERR_PTR if things went bad. ERR_PTR(-EINVAL) * if requested algorithm is not supported, ERR_PTR(-ENOMEM) in - * case of allocation error. + * case of allocation error, or any other error potentially + * returned by functions zcomp_strm_{multi,single}_create. */ struct zcomp *zcomp_create(const char *compress, int max_strm) { struct zcomp *comp; struct zcomp_backend *backend; + int error; backend = find_backend(compress); if (!backend) @@ -342,12 +344,12 @@ struct zcomp *zcomp_create(const char *compress, int max_strm) comp->backend = backend; if (max_strm > 1) - zcomp_strm_multi_create(comp, max_strm); + error = zcomp_strm_multi_create(comp, max_strm); else - zcomp_strm_single_create(comp); - if (!comp->stream) { + error = zcomp_strm_single_create(comp); + if (error) { kfree(comp); - return ERR_PTR(-ENOMEM); + return ERR_PTR(error); } return comp; } -- 1.9.1