From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752905AbbIGONO (ORCPT ); Mon, 7 Sep 2015 10:13:14 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:40876 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751251AbbIGONN (ORCPT ); Mon, 7 Sep 2015 10:13:13 -0400 From: Luis Henriques To: Minchan Kim , Nitin Gupta Cc: Sergey Senozhatsky , linux-kernel@vger.kernel.org Subject: [PATCH v2] zram: fix possible use after free in zcomp_create() Date: Mon, 7 Sep 2015 15:13:10 +0100 Message-Id: <1441635190-13991-1-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <20150907133332.GA539@swordfish> References: <20150907133332.GA539@swordfish> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org zcomp_create() verifies the success of zcomp_strm_{multi,siggle}_create() through comp->stream, which can potentially be pointing to memory that was freed if these functions returned an error. Fixes: beca3ec71fe5 ("zram: add multi stream functionality") Cc: stable@vger.kernel.org Signed-off-by: Luis Henriques --- Changes since v1: * Check zcomp_strm_{multi,siggle}_create() return code instead comp->stream (suggested by Sergey) drivers/block/zram/zcomp.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index 965d1afb0eaa..8d2cdfd307db 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -336,6 +336,7 @@ struct zcomp *zcomp_create(const char *compress, int max_strm) { struct zcomp *comp; struct zcomp_backend *backend; + int ret; backend = find_backend(compress); if (!backend) @@ -347,10 +348,10 @@ struct zcomp *zcomp_create(const char *compress, int max_strm) comp->backend = backend; if (max_strm > 1) - zcomp_strm_multi_create(comp, max_strm); + ret = zcomp_strm_multi_create(comp, max_strm); else - zcomp_strm_single_create(comp); - if (!comp->stream) { + ret = zcomp_strm_single_create(comp); + if (ret) { kfree(comp); return ERR_PTR(-ENOMEM); }