From nobody Thu Dec 18 22:22:24 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C8EEC4708E for ; Mon, 2 Jan 2023 14:59:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235972AbjABO7s (ORCPT ); Mon, 2 Jan 2023 09:59:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233295AbjABO7p (ORCPT ); Mon, 2 Jan 2023 09:59:45 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AAD0A641E for ; Mon, 2 Jan 2023 06:58:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1672671538; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=FH/Lp9MlKLCKaZbT73kzq05x4X87GgNm5ap75FWZ5H4=; b=FVpgLhlSJkKdJ1Gvo4o2uj33PiBkFDYYxJx1F4xXM7IRAoQACJbkwDhNft7OI/4HBlZLH0 9mqw0GxhHeqqSKvMMVnPdbJFfJUmV249DADFI29Uf1rfEW21La6n177E5IyFVIRZIwRWNG w0+UCB6ZLXHtvOHTaCPqTTyyCNNb5o4= Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-611-xjxFSBZ3N7inYxqTvNjKHQ-1; Mon, 02 Jan 2023 09:58:57 -0500 X-MC-Unique: xjxFSBZ3N7inYxqTvNjKHQ-1 Received: by mail-pf1-f197.google.com with SMTP id a1-20020a056a001d0100b0057a6f74d7bcso12978531pfx.1 for ; Mon, 02 Jan 2023 06:58:57 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=FH/Lp9MlKLCKaZbT73kzq05x4X87GgNm5ap75FWZ5H4=; b=Z5DxEQJvjiAA6b+EFgYSeFxbfgGZ4itPKLjxbXeWLKu2HX5d/2/Fnk53WfaS9EytJc B0Mb2A2ZDHwNm90nR+e1UB4CViqYnQY0enDU9MgHuLnbqAjV0WDzBzNdFPyk3YITBRFD 0S8V/hs+ur/vXaNK/WF51VlYfc3+nNQOa/oPxL7TzvG+biKfahKVqv2jZRlS+h+qKqUv bQXbdxoqwmOLW3SiEijoNMSEEPY6tgpnUN7nguXZVlf+0dhCuCHALbpt0nI9GnE0M52/ IVR4GCi1NnsliyI5jyX8ysIwsCQzBEPzX5uG15bV2LmbK81/+JR7bjj5daN9tCcSSYli 5M/g== X-Gm-Message-State: AFqh2kqlgeYSCiTk8YpyMoz/nL1Fr9Vj/hBQE8viuGW9Xf6JybEQC8jQ EHcrRZTodSJLiZJOp5ZNQrSmPk2KJdN7HQml4zgGgjIQK41sn1G5sFPz9FYglLd31j2J0QOtR6F ovyNuOEJoRJRCm2ZIDvGcApFZ X-Received: by 2002:aa7:90d9:0:b0:580:df2d:47c4 with SMTP id k25-20020aa790d9000000b00580df2d47c4mr32414670pfk.19.1672671536545; Mon, 02 Jan 2023 06:58:56 -0800 (PST) X-Google-Smtp-Source: AMrXdXu/jU0eyfX/7zCrMxSUEB4WmKwgUUKrVBc8mnkQozOF8ZixobVxmpjajys62AXlefjhUtgIVA== X-Received: by 2002:aa7:90d9:0:b0:580:df2d:47c4 with SMTP id k25-20020aa790d9000000b00580df2d47c4mr32414652pfk.19.1672671536244; Mon, 02 Jan 2023 06:58:56 -0800 (PST) Received: from localhost.localdomain ([240d:1a:c0d:9f00:ca6:1aff:fead:cef4]) by smtp.gmail.com with ESMTPSA id w18-20020aa79a12000000b00581816425f3sm10503683pfj.112.2023.01.02.06.58.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Jan 2023 06:58:55 -0800 (PST) From: Shigeru Yoshida To: tytso@mit.edu, adilger.kernel@dilger.ca Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Shigeru Yoshida , syzbot+bf4bb7731ef73b83a3b4@syzkaller.appspotmail.com Subject: [PATCH] ext4: Verify extent header in ext4_find_extent() Date: Mon, 2 Jan 2023 14:58:33 +0000 Message-Id: <20230102145833.2758-1-syoshida@redhat.com> X-Mailer: git-send-email 2.39.0 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" syzbot reported use-after-free in ext4_find_extent() [1]. If there is a corrupted file system, this can cause invalid memory access. This patch fixes the issue by verifying extent header. Reported-by: syzbot+bf4bb7731ef73b83a3b4@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=3Dcd95cb722bfa1234ac4c78345c8953= ee2e7170d0 [1] Signed-off-by: Shigeru Yoshida --- fs/ext4/extents.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 9de1c9d1a13d..79bfa583ab1d 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -901,6 +901,9 @@ ext4_find_extent(struct inode *inode, ext4_lblk_t block, ret =3D -EFSCORRUPTED; goto err; } + ret =3D ext4_ext_check(inode, eh, depth, 0); + if (ret) + goto err; =20 if (path) { ext4_ext_drop_refs(path); --=20 2.38.1