From patchwork Thu Sep 28 00:38:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Jinchao X-Patchwork-Id: 145652 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:cae8:0:b0:403:3b70:6f57 with SMTP id r8csp2989796vqu; Wed, 27 Sep 2023 17:39:22 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGMPrYb2e5T0bZBfMufntpFZUq1nLDQOh15jPNcAU30zh71N2g/yBySGk76bhTYFpfOjodU X-Received: by 2002:a17:903:2347:b0:1c6:28f6:9539 with SMTP id c7-20020a170903234700b001c628f69539mr3238253plh.21.1695861561882; Wed, 27 Sep 2023 17:39:21 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1695861561; cv=none; d=google.com; s=arc-20160816; b=zp1upLyuHyyj6AUHBZdiuff/BjmooETkfE0bBz9C9DgGQVgj7ZjtYC1HcM5+5TUpl5 vnWMzSaawkBxIGF5ys/LdzJ8aWdl9ul6ksV2s/QrxCoRgPv35UHyppsHza5y7EnRzeWz AN6Y/Eu1I8bnOoviw2QffzxGw2jV7Qlv5JxgRiscvQ8e/m8kr9Yp0fBKLrykiUG1fhYs kO3n5OHOv03gma8qDsxy8CRfuWejxZ5IhmzAyGNHWYfqDlzEoVDM6DldX9lrYV9baVFx 9uEmYYGlL/wtSMj5s0dH+Kqj35O4cC4Y0AyGyztE0CJGvJDhNRKMQe2yY2UjvbC6MXar 2HYg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-disposition:mime-version:message-id :subject:to:from:date; bh=uvlWP8nqZGc9as4ViQpC6BtKJBvMe2hVmTOcQ1wHyLA=; fh=gewWbXrdZafqzEUXtSzJ0H+AnVKmjuUnxVmHigDeMhk=; b=K8xrYO8vrJbbs7YMv1cklNX6FFat0vgQ/3sCd8teNEyc8Gj5szRsAMxb6fpdrkgbbc 6JRBrnOfX+7E857R+2VUHHWebAWI+sGah+A6+dnYN/XnITvdHMAwEGRCAAmCA52Uogve xLq1PzPPb3+3mH3dtnGkvX8YapoXibLuJv13hcCEDLO71x9kl5BG5uJj8zhEFsiEEj4f TgKqrnmHrxWZJ9n3Wafr8kYYRnFITIJiieWTL4/K0W4ghmtN2eoE8Sq88xds9ReC05ob SKLTTrfj8FYutOTt5+2fIH3KcjdudfDbA+3UIaGIZrElCnw0ksvnKAEEJquT6Bf8DXew ImOA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:6 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from pete.vger.email (pete.vger.email. [2620:137:e000::3:6]) by mx.google.com with ESMTPS id l11-20020a170903120b00b001c0eefc0dfesi18913504plh.130.2023.09.27.17.39.21 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 27 Sep 2023 17:39:21 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:6 as permitted sender) client-ip=2620:137:e000::3:6; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:6 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by pete.vger.email (Postfix) with ESMTP id F29B581A73E0; Wed, 27 Sep 2023 17:39:18 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at pete.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229831AbjI1AjH (ORCPT + 20 others); Wed, 27 Sep 2023 20:39:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229500AbjI1AjH (ORCPT ); Wed, 27 Sep 2023 20:39:07 -0400 Received: from wxsgout04.xfusion.com (wxsgout03.xfusion.com [36.139.52.80]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 90DE8F5; Wed, 27 Sep 2023 17:39:04 -0700 (PDT) Received: from wuxshcsitd00600.xfusion.com (unknown [10.32.133.213]) by wxsgout04.xfusion.com (SkyGuard) with ESMTPS id 4RwvgT1zx1z9y75B; Thu, 28 Sep 2023 08:36:53 +0800 (CST) Received: from localhost (10.82.147.3) by wuxshcsitd00600.xfusion.com (10.32.133.213) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Thu, 28 Sep 2023 08:38:54 +0800 Date: Thu, 28 Sep 2023 08:38:53 +0800 From: Wang Jinchao To: Steffen Klassert , Daniel Jordan , , Subject: [PATCH v2] padata: Fix the UAF issue related to parallel_data Message-ID: MIME-Version: 1.0 Content-Disposition: inline X-Originating-IP: [10.82.147.3] X-ClientProxiedBy: wuxshcsitd00600.xfusion.com (10.32.133.213) To wuxshcsitd00600.xfusion.com (10.32.133.213) X-Spam-Status: No, score=-0.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on pete.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (pete.vger.email [0.0.0.0]); Wed, 27 Sep 2023 17:39:19 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1778239733557814804 X-GMAIL-MSGID: 1778239733557814804 In a high-load arm64 environment, the pcrypt_aead01 test in LTP can lead to system UAF (Use-After-Free) issues. Due to the lengthy analysis of the pcrypt_aead01 function call, I'll describe the problem scenario using a simplified model: Suppose there's a user of padata named `user_function` that adheres to the padata requirement of calling `padata_free_shell` after `serial()` has been invoked, as demonstrated in the following code: ```c struct request { struct padata_priv padata; struct completion *done; }; void parallel(struct padata_priv *padata) { do_something(); } void serial(struct padata_priv *padata) { struct request *request = container_of(padata, struct request, padata); complete(request->done); } void user_function() { DECLARE_COMPLETION(done) padata->parallel = parallel; padata->serial = serial; padata_do_parallel(); wait_for_completion(&done); padata_free_shell(); } ``` In the corresponding padata.c file, there's the following code: ```c static void padata_serial_worker(struct work_struct *serial_work) { ... cnt = 0; while (!list_empty(&local_list)) { ... padata->serial(padata); cnt++; } local_bh_enable(); if (refcount_sub_and_test(cnt, &pd->refcnt)) padata_free_pd(pd); } ``` Because of the high system load and the accumulation of unexecuted softirq at this moment, `local_bh_enable()` in padata takes longer to execute than usual. Subsequently, when accessing `pd->refcnt`, `pd` has already been released by `padata_free_shell()`, resulting in a UAF issue with `pd->refcnt`. The fix is straightforward: add `refcount_dec_and_test` before calling `padata_free_pd` in `padata_free_shell`. Signed-off-by: Wang Jinchao Acked-by: Daniel Jordan --- V2: To satisfy Sparse, use rcu_dereference_protected. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202309270829.xHgTOMKw-lkp@intel.com/ V1: https://lore.kernel.org/all/ZRE4XvOOhz4HSOgR@fedora/ kernel/padata.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/padata.c b/kernel/padata.c index 222d60195de6..acef1e703a8b 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -1107,7 +1107,9 @@ void padata_free_shell(struct padata_shell *ps) mutex_lock(&ps->pinst->lock); list_del(&ps->list); - padata_free_pd(rcu_dereference_protected(ps->pd, 1)); + struct parallel_data *pd = rcu_dereference_protected(ps->pd, 1); + if (refcount_dec_and_test(&pd->refcnt)) + padata_free_pd(pd); mutex_unlock(&ps->pinst->lock); kfree(ps);