From patchwork Fri Feb 17 14:00:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Mark Wielaard X-Patchwork-Id: 65183 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 92F3D383FB81 for ; Fri, 17 Feb 2023 14:00:41 +0000 (GMT) X-Original-To: elfutils-devel@sourceware.org Delivered-To: elfutils-devel@sourceware.org Received: from gnu.wildebeest.org (gnu.wildebeest.org [45.83.234.184]) by sourceware.org (Postfix) with ESMTPS id D3ACF3858C31 for ; Fri, 17 Feb 2023 14:00:34 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org D3ACF3858C31 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=klomp.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=klomp.org Received: from r6.localdomain (82-217-174-174.cable.dynamic.v4.ziggo.nl [82.217.174.174]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by gnu.wildebeest.org (Postfix) with ESMTPSA id A14593000648; Fri, 17 Feb 2023 15:00:33 +0100 (CET) Received: by r6.localdomain (Postfix, from userid 1000) id 4CC3A3401CE; Fri, 17 Feb 2023 15:00:33 +0100 (CET) From: Mark Wielaard To: elfutils-devel@sourceware.org Cc: Mark Wielaard Subject: [PATCH] libasm: Fix use-after-free issue with circular single linked list cleanup Date: Fri, 17 Feb 2023 15:00:27 +0100 Message-Id: <20230217140027.125332-1-mark@klomp.org> X-Mailer: git-send-email 2.39.1 MIME-Version: 1.0 X-Spam-Status: No, score=-3036.1 required=5.0 tests=BAYES_00, GIT_PATCH_0, JMQ_SPF_NEUTRAL, KAM_DMARC_STATUS, RCVD_IN_BARRACUDACENTRAL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: elfutils-devel@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Elfutils-devel mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , Errors-To: elfutils-devel-bounces+patchwork=sourceware.org@sourceware.org Sender: "Elfutils-devel" Pointed out by gcc 12 with -Wuse-after-free=3 In function ‘free_section’ asm_end.c:552:17: error: pointer ‘data’ used after ‘free’ [-Werror=use-after-free] 552 | while (oldp != scnp->content); | ~~~~~^~~~~~~~~~~~~~~~ asm_end.c:550:9: note: call to ‘free’ here 550 | free (oldp); | ^~~~~~~~~~~ Fix by freeing scnp->content last. Signed-off-by: Mark Wielaard --- libasm/ChangeLog | 4 ++++ libasm/asm_end.c | 18 ++++++++++-------- 2 files changed, 14 insertions(+), 8 deletions(-) diff --git a/libasm/ChangeLog b/libasm/ChangeLog index a12d14b3..f23d5914 100644 --- a/libasm/ChangeLog +++ b/libasm/ChangeLog @@ -1,3 +1,7 @@ +2023-02-17 Mark Wielaard + + * asm_end.c (free_section): free scnp->content last. + 2022-12-20 Mark Wielaard * disasm_begin.c: Include libeblP.h. diff --git a/libasm/asm_end.c b/libasm/asm_end.c index c06d2366..29165ac4 100644 --- a/libasm/asm_end.c +++ b/libasm/asm_end.c @@ -541,16 +541,18 @@ free_section (AsmScn_t *scnp) if (scnp->subnext != NULL) free_section (scnp->subnext); + /* This is a circular single linked list. */ struct AsmData *data = scnp->content; if (data != NULL) - do - { - oldp = data; - data = data->next; - free (oldp); - } - while (oldp != scnp->content); - + { + while (data != scnp->content) + { + oldp = data; + data = data->next; + free (oldp); + } + free (scnp->content); + } free (scnp); }