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 650EBC433F5 for ; Wed, 3 Nov 2021 14:22:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4410B61053 for ; Wed, 3 Nov 2021 14:22:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232036AbhKCOZX (ORCPT ); Wed, 3 Nov 2021 10:25:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56748 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231834AbhKCOZW (ORCPT ); Wed, 3 Nov 2021 10:25:22 -0400 Received: from mail-pj1-x1036.google.com (mail-pj1-x1036.google.com [IPv6:2607:f8b0:4864:20::1036]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA839C061714 for ; Wed, 3 Nov 2021 07:22:45 -0700 (PDT) Received: by mail-pj1-x1036.google.com with SMTP id y14-20020a17090a2b4e00b001a5824f4918so1501057pjc.4 for ; Wed, 03 Nov 2021 07:22:45 -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=odOeSMEh9ZpBA89eL2qhRpEs4XuRy4e44peglvFnMtU=; b=XvnnyeRAxuitPImPJIlZ70HPKNSIKTcgcDDCY0BNYwKZWzeSb5fDk1B3m41sj1be5e JBE6X0HSXj9sHYamSvwZSv0DuNVWnqQ2rPGnd5vvxwHwHjRDOPLcfuYIriiJ7GUjv/Od 8BG9Kxs9jWpA1Xepdcr9KRfekCJQ0CmTHp+xZ5aQryS9DFroWIs6G/cYS+DuCdEP1Y5u scsALWMNUaNfM4hT5rvf+MJak6cx1BlCEdKDTUO49B5uDS3DftuL/XS+O43iZX1uxePw bVnhf1/EkcSTncJmKhvlbO72RoA2w0CDrgGISL1VMSgJQF5WpieOhKwKk3JT/ZmVIi4r Ghmg== 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=odOeSMEh9ZpBA89eL2qhRpEs4XuRy4e44peglvFnMtU=; b=ree8weNHoMtRXAKG8bUaK15UxQbh1E+WX6uUdG3xO6Uy0TB5X5Cdo97Ic5by/hnrC5 J8T7RcPe+5XAKFiyleFQ7HgeKExc17ceMP+Nwj4XinYGH70TF78CVB/vV2Pl2QWCSI3P KtyU2vXVvIvZD2mLyb6N0viZEmO4pAqYf959b0MiN4Qaga9J+wZLM/RZ2Sce+BH4+niP LqMorNGc3RZJVFCqu/gb+nLV2dEY/nwmodGGDLN43vyuUva29wNlvKgOZo81QolHiBxD gdKRXmnHayKvG/eI7PPJuR36ElrlHoz0OWqRRRqzMh4o/t0vkkPJNk02gUW/tD5EPwgo PGzg== X-Gm-Message-State: AOAM531jMWSgn7CW8cMrQ7AlUvDQBteEOFfyM2vGZ2wG1V5DoM+gvM1A 8hRtkoZGainhdvWblAxaam0= X-Google-Smtp-Source: ABdhPJx9boeHyijVo0W1PSZZtMsybz7on3bwcC9dzysQlM/8X3F4rrEQ+xNqP6JGnTelBQ2qFY9VIg== X-Received: by 2002:a17:90b:1293:: with SMTP id fw19mr14920912pjb.155.1635949365327; Wed, 03 Nov 2021 07:22:45 -0700 (PDT) Received: from localhost.localdomain ([94.177.118.123]) by smtp.gmail.com with ESMTPSA id z21sm2855893pfk.31.2021.11.03.07.22.42 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 03 Nov 2021 07:22:44 -0700 (PDT) From: Dongliang Mu To: Jaegeuk Kim , Chao Yu Cc: Dongliang Mu , linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: [PATCH] fs: f2fs: fix UAF in f2fs_available_free_memory Date: Wed, 3 Nov 2021 22:22:27 +0800 Message-Id: <20211103142228.1235864-1-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 f2fs_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 switching the order of f2fs_build_segment_manager and f2fs_build_node_manager. Signed-off-by: Dongliang Mu --- fs/f2fs/super.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 78ebc306ee2b..1a23b64cfb74 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -4135,18 +4135,18 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) } /* setup f2fs internal modules */ - err = f2fs_build_segment_manager(sbi); - if (err) { - f2fs_err(sbi, "Failed to initialize F2FS segment manager (%d)", - err); - goto free_sm; - } err = f2fs_build_node_manager(sbi); if (err) { f2fs_err(sbi, "Failed to initialize F2FS node manager (%d)", err); goto free_nm; } + err = f2fs_build_segment_manager(sbi); + if (err) { + f2fs_err(sbi, "Failed to initialize F2FS segment manager (%d)", + err); + goto free_sm; + } /* For write statistics */ sbi->sectors_written_start = f2fs_get_sectors_written(sbi); @@ -4351,10 +4351,10 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) sbi->node_inode = NULL; free_stats: f2fs_destroy_stats(sbi); -free_nm: - f2fs_destroy_node_manager(sbi); free_sm: f2fs_destroy_segment_manager(sbi); +free_nm: + f2fs_destroy_node_manager(sbi); f2fs_destroy_post_read_wq(sbi); stop_ckpt_thread: f2fs_stop_ckpt_thread(sbi); -- 2.25.1