From patchwork Mon Oct 16 01:15:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wang Jinchao X-Patchwork-Id: 153119 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a05:612c:2908:b0:403:3b70:6f57 with SMTP id ib8csp3175871vqb; Sun, 15 Oct 2023 18:16:16 -0700 (PDT) X-Google-Smtp-Source: AGHT+IElbcYh4xcsJe5M3iju9Dl/HR5ziKRdW9YHMb7eKmSF2vy9LYOGour+n/DPdNBYk1dHHc1T X-Received: by 2002:a05:6a20:3d85:b0:163:f945:42c4 with SMTP id s5-20020a056a203d8500b00163f94542c4mr39118295pzi.1.1697418976438; Sun, 15 Oct 2023 18:16:16 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1697418976; cv=none; d=google.com; s=arc-20160816; b=xbIfdGZ58owiPQ173bVNfB9Liq8fUutdhMKuNzgMa2CbAcrye4jD6eXHJPmNcB3JNk QgrDAuU2aye8KWvdQ27N25eHwvKf6F5DVZjP2/iUesp5hLpnB+RqKjBxYN+Ug+8OX7BN jdNr7r9Fr/vmS9UM2e+AyM8AJhpRT/Tqatjkvh73CjcFxilQj5sBVKAwUeMKuftrf3Dl 0p3XvHe7WMMAmRRU/SVwIba/fxVpAjeXcNacNjSSeDTpPIIgjpzwfEStP0KSC9hSppaV XLNjvXuKWAfAmoAUoGoTAhKNxnHOCiJlKC9QyDqNO3lHg+RD2lCH70VZd6uvoEh9ySjE Ms3A== 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:cc:to:from:date; bh=CgwFZehJHm9S3rUaCk3uMpshIrNz1MSCOJzQ4y6CUaw=; fh=7F+ruHH5QcOTmRba7j1bGKOB4p1lK5yntKtecISCuVs=; b=lUL0rCKbOAXDci4jVPaA2umoLxfbUfh/1uc8iNHMYHvC0kAaYba1ZKGgd2DENMuiN/ eX08CNpSGVezck6/rUNABSocN+J7/X3ogsLfPhz8gh2GP/xhr4KT0L2YN8xTBvZGBpbm CP/RAD6n3HR0HfFXmSC8r/yg32af0zQpOJ2dlbaxeOeZl8F5wwsdJY4NYBepPJnAh/PS iXX3exwZohtSo2RCLAnaQZRABH9y/ct14wK4o+K1ZSGhlX1G2NfnEyIFBqRQAX+6MaTO dpDVhsBZaf6sn3kzLNH6D0oqtZ2QD+yyPIYctuH4IpBKJaWbjHlxR/UCQoCM4MH1Dnyo Xkzg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: from fry.vger.email (fry.vger.email. [2620:137:e000::3:8]) by mx.google.com with ESMTPS id k6-20020a634b46000000b00565d88203c8si6891359pgl.535.2023.10.15.18.16.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 15 Oct 2023 18:16:16 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 as permitted sender) client-ip=2620:137:e000::3:8; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:8 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 fry.vger.email (Postfix) with ESMTP id E39A8809B6FA; Sun, 15 Oct 2023 18:16:13 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at fry.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230029AbjJPBP5 (ORCPT + 19 others); Sun, 15 Oct 2023 21:15:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229459AbjJPBPz (ORCPT ); Sun, 15 Oct 2023 21:15:55 -0400 Received: from wxsgout04.xfusion.com (wxsgout03.xfusion.com [36.139.52.80]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE325A9; Sun, 15 Oct 2023 18:15:50 -0700 (PDT) Received: from wuxshcsitd00600.xfusion.com (unknown [10.32.133.213]) by wxsgout04.xfusion.com (SkyGuard) with ESMTPS id 4S7zct4knwz9xn1n; Mon, 16 Oct 2023 09:13:02 +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; Mon, 16 Oct 2023 09:15:21 +0800 Date: Mon, 16 Oct 2023 09:15:21 +0800 From: WangJinchao To: Steffen Klassert , Daniel Jordan , , CC: Subject: [PATCH v4] padata: Fix refcnt handling in padata_free_shell() Message-ID: <202310160854+0800-wangjinchao@xfusion.com> 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 fry.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 (fry.vger.email [0.0.0.0]); Sun, 15 Oct 2023 18:16:13 -0700 (PDT) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1779872800540594752 X-GMAIL-MSGID: 1779872800540594752 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`. Fixes: 07928d9bfc81 ("padata: Remove broken queue flushing") Signed-off-by: WangJinchao Acked-by: Daniel Jordan Acked-by: Daniel Jordan --- V4: Included Daniel's ack Included Herbert's ack V3: https://lore.kernel.org/all/ZSDWAcUxXcwD4YUZ@fedora/ Included Daniel's ack introduced wrong patch V2: https://lore.kernel.org/all/ZRTLHY5A+VqIKhA2@fedora/ 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 | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/padata.c b/kernel/padata.c index 222d60195de6..73108ac75f03 100644 --- a/kernel/padata.c +++ b/kernel/padata.c @@ -1102,12 +1102,15 @@ EXPORT_SYMBOL(padata_alloc_shell); */ void padata_free_shell(struct padata_shell *ps) { + struct parallel_data *pd; if (!ps) return; mutex_lock(&ps->pinst->lock); list_del(&ps->list); - padata_free_pd(rcu_dereference_protected(ps->pd, 1)); + 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);