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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67BEDC433F5 for ; Thu, 4 Nov 2021 08:22:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 461CA610D0 for ; Thu, 4 Nov 2021 08:22:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230494AbhKDIY7 (ORCPT ); Thu, 4 Nov 2021 04:24:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230084AbhKDIY4 (ORCPT ); Thu, 4 Nov 2021 04:24:56 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 009AAC061714 for ; Thu, 4 Nov 2021 01:22:19 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id u11so6014372plf.3 for ; Thu, 04 Nov 2021 01:22:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CyUgf+E27izz8eZXu5EdO3onvde6cXVaxrtlTel0Gjk=; b=T4HeVGgFFrZdkuI85Bv3La9ebDCcKARia1U8w6+C7sAJH4G3+09PgbpTXs/lka+buB OF5J3MhrtOZsgBA2oihZSiHfOBA6gqBVW2+ANchQrjtPDzICz0bnwT0GoYxXn2S3Eei7 eUlrhQCzE34Dm7ZJJ1b00zu4NLxaYmYoV3t49stkPfwhxvUbcqNBY311qyOYNOFv+Yud ljH38voo6ORAJ9v5mZmC+qVhPd5p+wiy4A4THXrZ7Whnm6w8iHMrzPzESRpbhnHxAULb ab19THiXMDgDbFks9w4XGqOlum4stt5ChV09IIOL2ZuGJnMWdPPoE9Vnv4XxixfwEsPv oG/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CyUgf+E27izz8eZXu5EdO3onvde6cXVaxrtlTel0Gjk=; b=2VINZOyO9RziDtfO7PodLazwlRrNNmUx5VsljNX5cueH0JJmJS045Ev9gD1MhTDFt8 gZlb2Jbg9mN5oB7dOBQRAZYnvO79+0f0yr1VXtLr4ZbBkxX63zUNV7LrpDsaKRVFGzf3 zj/ItUpUYpkzXCec2JYlO6iLU3V9GXZ8ruMAlqXePJUAnCM7Q93U+s2CJCFMy7UE4KRJ ZlWckILa0fXaIoMjGYS2WDOJklrHmCxYe29BamdnSlI5ZAHXSch287GimJ1XBwzz90sj hDp64VMV8TGmcMhQkOfAXTApp7JMopCUmbK7qZNuf/LDxHnCgzfIlZWKgM5Ye+thiyiw BPjQ== X-Gm-Message-State: AOAM530fevRjG8SkJpKAIpIoO9+mt6G28DNKVjcetrK/DJyd302lLR3E OMIHqvGqOZxD3C/6jTsNJoU= X-Google-Smtp-Source: ABdhPJzIGhrUoaVah+gozgNMaDDVh94KHE4PVsAecpIA5T1RBgEXLmZSdPSO6V1LraPH7O2zGbWk4w== X-Received: by 2002:a17:90b:155:: with SMTP id em21mr20866570pjb.12.1636014138415; Thu, 04 Nov 2021 01:22:18 -0700 (PDT) Received: from localhost.localdomain ([94.177.118.123]) by smtp.gmail.com with ESMTPSA id m3sm4826985pfk.190.2021.11.04.01.22.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 Nov 2021 01:22:17 -0700 (PDT) From: Dongliang Mu To: Jaegeuk Kim , Chao Yu , Sahitya Tummala Cc: Dongliang Mu , linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: [PATCH v2] fs: f2fs: fix UAF in f2fs_available_free_memory Date: Thu, 4 Nov 2021 16:22:01 +0800 Message-Id: <20211104082202.1286551-1-mudongliangabcd@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org if2fs_fill_super -> f2fs_build_segment_manager -> create_discard_cmd_control -> f2fs_start_discard_thread It invokes kthread_run to create a thread and run issue_discard_thread. However, if f2fs_build_node_manager fails, the control flow goes to free_nm and calls f2fs_destroy_node_manager. This function will free sbi->nm_info. However, if issue_discard_thread accesses sbi->nm_info after the deallocation, but before the f2fs_stop_discard_thread, it will cause UAF(Use-after-free). -> f2fs_destroy_segment_manager -> destroy_discard_cmd_control -> f2fs_stop_discard_thread Fix this by stopping discard thread before f2fs_destroy_node_manager. Note that, the commit d6d2b491a82e1 introduces the call of f2fs_available_free_memory into issue_discard_thread. Fixes: d6d2b491a82e ("f2fs: allow to change discard policy based on cached discard cmds") Signed-off-by: Dongliang Mu --- fs/f2fs/super.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 78ebc306ee2b..dbe040b66802 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -4352,6 +4352,8 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) free_stats: f2fs_destroy_stats(sbi); free_nm: + /* stop discard thread before destroying node manager */ + f2fs_stop_discard_thread(sbi); f2fs_destroy_node_manager(sbi); free_sm: f2fs_destroy_segment_manager(sbi); -- 2.25.1