From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 232BFC43387 for ; Fri, 14 Dec 2018 16:59:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DEE94206BA for ; Fri, 14 Dec 2018 16:59:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730102AbeLNQ74 (ORCPT ); Fri, 14 Dec 2018 11:59:56 -0500 Received: from www.osadl.org ([62.245.132.105]:42959 "EHLO www.osadl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729409AbeLNQ74 (ORCPT ); Fri, 14 Dec 2018 11:59:56 -0500 Received: from debian01.hofrr.at (178.115.242.59.static.drei.at [178.115.242.59]) by www.osadl.org (8.13.8/8.13.8/OSADL-2007092901) with ESMTP id wBEGxVdk014507; Fri, 14 Dec 2018 17:59:40 +0100 From: Nicholas Mc Guire To: Josh Poimboeuf Cc: Jessica Yu , Jiri Kosina , Miroslav Benes , Petr Mladek , live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, Nicholas Mc Guire Subject: [PATCH 2/2] livepatch: check kzalloc return values Date: Fri, 14 Dec 2018 17:56:10 +0100 Message-Id: <1544806570-21299-2-git-send-email-hofrat@osadl.org> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1544806570-21299-1-git-send-email-hofrat@osadl.org> References: <1544806570-21299-1-git-send-email-hofrat@osadl.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org kzalloc() return should always be checked - notably in example code where this may be seen as reference. On failure of allocation in livepatch_fix1_dummy_alloc() respectively dummy_alloc() previous allocation is freed (thanks to Petr Mladek for catching this) and NULL returned. Signed-off-by: Nicholas Mc Guire Fixes: 439e7271dc2b ("livepatch: introduce shadow variable API") --- Problem located with an experimental coccinelle script Patch was compile tested with: x86_64_defconfig + FTRACE=y FUNCTION_TRACER=y, EXPERT=y, LATENCYTOP=y, SAMPLES=y, SAMPLE_LIVEPATCH=y Patch is against 4.20-rc6 (localversion-next is next-20181214) on top of 0001-livepatch-fix-non-static-warnings.patch samples/livepatch/livepatch-shadow-fix1.c | 5 +++++ samples/livepatch/livepatch-shadow-mod.c | 4 ++++ 2 files changed, 9 insertions(+) diff --git a/samples/livepatch/livepatch-shadow-fix1.c b/samples/livepatch/livepatch-shadow-fix1.c index eaab10f..1974eb5 100644 --- a/samples/livepatch/livepatch-shadow-fix1.c +++ b/samples/livepatch/livepatch-shadow-fix1.c @@ -89,6 +89,11 @@ static __noclone struct dummy *livepatch_fix1_dummy_alloc(void) * pointer to handle resource release. */ leak = kzalloc(sizeof(int), GFP_KERNEL); + if (!leak) { + kfree(d); + return NULL; + } + klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL, shadow_leak_ctor, leak); diff --git a/samples/livepatch/livepatch-shadow-mod.c b/samples/livepatch/livepatch-shadow-mod.c index dc69da0..b4ece36 100644 --- a/samples/livepatch/livepatch-shadow-mod.c +++ b/samples/livepatch/livepatch-shadow-mod.c @@ -123,6 +123,10 @@ static __noclone noinline struct dummy *dummy_alloc(void) /* Oops, forgot to save leak! */ leak = kzalloc(sizeof(int), GFP_KERNEL); + if (!leak) { + kfree(d); + return NULL; + } pr_info("%s: dummy @ %p, expires @ %lx\n", __func__, d, d->jiffies_expire); -- 2.1.4