From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender-of-o57.zoho.eu (sender-of-o57.zoho.eu [136.143.169.57]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F315036F426; Sat, 1 Aug 2026 07:13:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.169.57 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785568428; cv=pass; b=Ab0D277LuQ0IK9R845d5sYBZ1fbkmzvB9NfXc918gUZbDlH08vG/6pjuJolyLWOgOgYEF+EN1uXV8wI1FI9CovDPmgnU6D5LEjTKv06tWrru+btxcgE9puresUVz+jhPK/1OG1b934IkF2z/jWmFHAa8/td9ZHXntFXGUXJB+Ho= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785568428; c=relaxed/simple; bh=oizwROL4CHKC60FysL967VYh8hqBgJnGvmTxG7Pv2ss=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Sn6+AkHrSBko5UvM/gUArqViL7P3BfFeK4iaTWV6dTQ86wOSNORdKRuqz84eKmnMVNuzCil61q8i74+oQHXz2xvAMhFWgBAlaWCywQTBmQbutB/zAXUNf/wiRRV3TKzAfMa4IuFY7C9SzaE5KL2KZCnasNOXjX8kvfeuPyDcfUA= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=iusegentoo.com; spf=pass smtp.mailfrom=iusegentoo.com; dkim=pass (1024-bit key) header.d=iusegentoo.com header.i=ali@iusegentoo.com header.b=hG2TByt3; arc=pass smtp.client-ip=136.143.169.57 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=iusegentoo.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iusegentoo.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=iusegentoo.com header.i=ali@iusegentoo.com header.b="hG2TByt3" ARC-Seal: i=1; a=rsa-sha256; t=1785568405; cv=none; d=zohomail.eu; s=zohoarc; b=h7axT5jtfCKDHoYtVZtckK6vLTlacVrY3fqcs5pGGHzISRFyR+ohZcsCBlGYUbXm1svcoxqOxIA5pF9D/2wqH5olnNRne1HWo6KNVI1TzyENUOscmmWGtPo7ATRky6j2QbljR2OoOAZlBthP2PwVoV9PB4MlVORAZuuYdN6tbVk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.eu; s=zohoarc; t=1785568405; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:Subject:Subject:To:To:Message-Id:Reply-To; bh=VFcBWjC5ahhLk/neaSsNkFwzuJ7YbdmtTkJ6fhx0ABw=; b=Vh2Uwd7HrABO/Yf2e0PE7E6Qxc7fXoKKHajsHyTcGyY6NW502Dm41MMpNqK7cAtLRRzwx5oIRWolbzoq0X17aCj8cfzX6OcGIdPY9x3nOwwz0jpAvlUDOiEnjozyNh84LJdxbWlyj6sQyiEEgfv3c6x4UGYOJM4ZDpAtspWCrME= ARC-Authentication-Results: i=1; mx.zohomail.eu; dkim=pass header.i=iusegentoo.com; spf=pass smtp.mailfrom=ali@iusegentoo.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1785568405; s=zmail; d=iusegentoo.com; i=ali@iusegentoo.com; h=From:From:To:To:Cc:Cc:Subject:Subject:Date:Date:Message-ID:In-Reply-To:MIME-Version:Content-Transfer-Encoding:Message-Id:Reply-To; bh=VFcBWjC5ahhLk/neaSsNkFwzuJ7YbdmtTkJ6fhx0ABw=; b=hG2TByt302FLPD9hkvrc+reFFieid3MDtXVW3r62oKsz5Ev80mssq8oIf2iHxh9s I6uSLfbBwapMY6Vd23DaUJs55MrsQV5+bzW6sYCFdUg1qR41HQQW9S9VKtRfX3dH5CC cR4v7UPBNFllRYMIyVAB5NC4eBKf0ce4LRLZmcVc= Received: by mx.zoho.eu with SMTPS id 1785568403940788.5619489921191; Sat, 1 Aug 2026 09:13:23 +0200 (CEST) From: Ali Ahmet Memis To: Alexander Viro , Christian Brauner Cc: Jan Kara , Kees Cook , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH 1/2] ufs: create the root dentry after loading cylinder metadata Date: Sat, 1 Aug 2026 10:12:57 +0300 Message-ID: <20260801071306.59484-2-ali@iusegentoo.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260801071306.59484-1-ali@iusegentoo.com> References: <20260801071306.59484-1-ali@iusegentoo.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-ZohoMailClient: External ufs_fill_super() installed sb->s_root before it loaded the cylinder group structures for a writable mount: sb->s_root = d_make_root(inode); ... if (!sb_rdonly(sb)) if (!ufs_read_cylinder_structures(sb)) goto failed; When ufs_read_cylinder_structures() failed, the error path freed the in-core superblock information and set sb->s_fs_info to NULL while sb->s_root stayed installed. get_tree_bdev() then reached deactivate_locked_super(), and because s_root was present, generic_shutdown_super() called sync_filesystem() and the put_super operation. Both dereference UFS_SB(sb), which is now NULL, so a mount that fails only while reading the cylinder groups oopses during teardown. A crafted image whose first cylinder group cannot be read reaches this path. Load the cylinder group metadata first and create the root dentry last, so the superblock is published to the VFS only once it is fully set up. ufs_setup_cstotal() and ufs_read_cylinder_structures() take only the super_block and do not use the root inode, so the reordering is safe. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: Ali Ahmet Memis --- fs/ufs/super.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/fs/ufs/super.c b/fs/ufs/super.c index c4831a8b9..7deecb395 100644 --- a/fs/ufs/super.c +++ b/fs/ufs/super.c @@ -1199,6 +1199,15 @@ static int ufs_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_maxbytes = ufs_max_bytes(sb); sb->s_max_links = UFS_LINK_MAX; + ufs_setup_cstotal(sb); + /* + * Read cylinder group structures + */ + if (!sb_rdonly(sb)) + if (!ufs_read_cylinder_structures(sb)) + goto failed; + + /* create the root dentry last, once UFS_SB(sb) is fully set up */ inode = ufs_iget(sb, UFS_ROOTINO); if (IS_ERR(inode)) { ret = PTR_ERR(inode); @@ -1210,14 +1219,6 @@ static int ufs_fill_super(struct super_block *sb, struct fs_context *fc) goto failed; } - ufs_setup_cstotal(sb); - /* - * Read cylinder group structures - */ - if (!sb_rdonly(sb)) - if (!ufs_read_cylinder_structures(sb)) - goto failed; - UFSD("EXIT\n"); return 0; -- 2.54.0