From patchwork Thu Dec 8 14:20:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Vrany X-Patchwork-Id: 61697 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 6BE45388DD5F for ; Thu, 8 Dec 2022 14:20:52 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 6BE45388DD5F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1670509252; bh=eThvUgUrl8ugqWJv3F6TKtXF2yCc2JZb9Bk7iVf7FGY=; h=To:CC:Subject:Date:List-Id:List-Unsubscribe:List-Archive: List-Post:List-Help:List-Subscribe:From:Reply-To:From; b=Qk2vitKLH23pglPFIwuh4iICKUCsLE2vEPeRXMaGuTlycdkZyf7NI7+PPV9VMlcPL YMkgX5T5oUc9bw7UrDyH+Hw8YWxjw4MtqcseIN0jWbhP1bYx1LUBfSmjgkbof6lrz7 Xp1bODsb8J73A2CrIe+hUxT2Mys3YJi1gT9QyuXM= X-Original-To: gdb-patches@sourceware.org Delivered-To: gdb-patches@sourceware.org Received: from us-smtp-delivery-114.mimecast.com (us-smtp-delivery-114.mimecast.com [170.10.133.114]) by sourceware.org (Postfix) with ESMTPS id EF15D3834872 for ; Thu, 8 Dec 2022 14:20:25 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org EF15D3834872 Received: from NAM11-CO1-obe.outbound.protection.outlook.com (mail-co1nam11lp2173.outbound.protection.outlook.com [104.47.56.173]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-214-DasTkN8jMIyOiXr_uRTH6Q-2; Thu, 08 Dec 2022 09:20:24 -0500 X-MC-Unique: DasTkN8jMIyOiXr_uRTH6Q-2 Received: from DM6PR17MB3113.namprd17.prod.outlook.com (2603:10b6:5:6::10) by MN2PR17MB4080.namprd17.prod.outlook.com (2603:10b6:208:206::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5880.10; Thu, 8 Dec 2022 14:20:22 +0000 Received: from DM6PR17MB3113.namprd17.prod.outlook.com ([fe80::9df4:7ed9:aca6:322e]) by DM6PR17MB3113.namprd17.prod.outlook.com ([fe80::9df4:7ed9:aca6:322e%4]) with mapi id 15.20.5880.016; Thu, 8 Dec 2022 14:20:22 +0000 To: gdb-patches@sourceware.org CC: Jan Vrany Subject: [PATCH] gdb: fix possible use-after-free when executing commands Date: Thu, 8 Dec 2022 14:20:14 +0000 Message-ID: <20221208142014.84759-1-jan.vrany@labware.com> X-Mailer: git-send-email 2.35.1 X-ClientProxiedBy: LO4P123CA0459.GBRP123.PROD.OUTLOOK.COM (2603:10a6:600:1aa::14) To DM6PR17MB3113.namprd17.prod.outlook.com (2603:10b6:5:6::10) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM6PR17MB3113:EE_|MN2PR17MB4080:EE_ X-MS-Office365-Filtering-Correlation-Id: eeda1aaf-ae3a-49d7-7f4c-08dad927574b X-MS-Exchange-AtpMessageProperties: SA X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0 X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:DM6PR17MB3113.namprd17.prod.outlook.com; PTR:; CAT:NONE; SFS:(13230022)(4636009)(396003)(366004)(136003)(346002)(39850400004)(376002)(451199015)(36756003)(2906002)(38350700002)(38100700002)(86362001)(8936002)(44832011)(83380400001)(1076003)(2616005)(186003)(316002)(6916009)(66899015)(5660300002)(6486002)(478600001)(6512007)(26005)(52116002)(4326008)(41300700001)(8676002)(66556008)(6666004)(66476007)(107886003)(66946007)(6506007); DIR:OUT; SFP:1101 X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: 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 X-OriginatorOrg: labware.com X-MS-Exchange-CrossTenant-Network-Message-Id: eeda1aaf-ae3a-49d7-7f4c-08dad927574b X-MS-Exchange-CrossTenant-AuthSource: DM6PR17MB3113.namprd17.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Dec 2022 14:20:21.9582 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: b5db0322-1aa0-4c0a-859c-ad0f96966f4c X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: MFmfTvXqokVrA20++8b/P1v57HTVoiWyLF5YGGGdkUU564pHmySaIFA1JLUkahehfZ7UlNLwtb8uzmkZEfOMyg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR17MB4080 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: labware.com X-Spam-Status: No, score=-12.4 required=5.0 tests=BAYES_00, GIT_PATCH_0, KAM_DMARC_STATUS, RCVD_IN_DNSWL_NONE, 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: gdb-patches@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Jan Vrany via Gdb-patches From: Jan Vrany Reply-To: Jan Vrany Errors-To: gdb-patches-bounces+patchwork=sourceware.org@sourceware.org Sender: "Gdb-patches" In principle, `execute_command()` does following: struct cmd_list_element *c; c = lookup_cmd ( ... ); ... /* If this command has been pre-hooked, run the hook first. */ execute_cmd_pre_hook (c); ... /* ...execute the command `c` ...*/ ... execute_cmd_post_hook (c); This may lead into use-after-free error. Imagine the command being executed is a user-defined Python command that redefines itself. In that case, struct `cmd_list_element` pointed to by `c` is deallocated during its execution so it is no longer valid when post hook is executed. To fix this case, this commit looks up the command once again after it is executed to get pointer to (possibly newly allocated) `cmd_list_element`. --- gdb/top.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/gdb/top.c b/gdb/top.c index e9794184f07..441ca3e14c1 100644 --- a/gdb/top.c +++ b/gdb/top.c @@ -655,6 +655,8 @@ execute_command (const char *p, int from_tty) } } + std::string c_name(c->name); + /* If this command has been pre-hooked, run the hook first. */ execute_cmd_pre_hook (c); @@ -694,7 +696,9 @@ execute_command (const char *p, int from_tty) maybe_wait_sync_command_done (was_sync); /* If this command has been post-hooked, run the hook last. */ - execute_cmd_post_hook (c); + c = lookup_cmd_exact (c_name.c_str (), cmdlist); + if (c != nullptr) + execute_cmd_post_hook (c); if (repeat_arguments != NULL && cmd_start == saved_command_line) {