From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D9A6B1714AE; Thu, 15 Aug 2024 13:31:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723728674; cv=none; b=iloDeXw088ZsDQIQFMAE4Wsmv705fMKicLrYV4TR2FSLhm7Az34g46rtv1i4cBiVDSkvi0IRAASDklgdgRDO2VVAf1QjKrNtDCDpaMr059OMeBXiDt9COBOkRlBp4SqtnbkrMTxBYTwMKTtq6VRcDpE1jFwjCu4g11ka0VNeAKQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723728674; c=relaxed/simple; bh=SONZvqMMuruNkWuIawfgJvHAZpDZXrHT+ghTLoPeVKY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oxs917MqAEz5gIHy8LPbX0yo4lcQpo1+bd6TQ6A+1PzKjmKyKLHcPRXQpk6coZOgkUciOI9pqpU4Jk2PChtnhN4ohRemUalk520S26jI6LVKMPg2ex3OpWZNOfGZbaGyo/V5OBCHQ5MdlVxbGxkWrm0iQCEn4q9rsPytoyYDfNc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=scXIKevQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="scXIKevQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59D6AC32786; Thu, 15 Aug 2024 13:31:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723728674; bh=SONZvqMMuruNkWuIawfgJvHAZpDZXrHT+ghTLoPeVKY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=scXIKevQKYx5/QalayMoHe5XniR2p7gshVowuh/eaDbXDBRvAhC6UroHdjEsMBX2T iVNfcTUt/k1vW2AiScGUksr+FhCgWyoBs/XfVOPeewbIn1ZTkkpBL6mcB3D8BNDUzB lgZWyOrttexd3pEV5hNIxPxcDeGws3W4ZeN5mUyQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+ae688d469e36fb5138d0@syzkaller.appspotmail.com, stable@kernel.org, Baokun Li , Jan Kara , Theodore Tso Subject: [PATCH 4.19 073/196] ext4: make sure the first directory block is not a hole Date: Thu, 15 Aug 2024 15:23:10 +0200 Message-ID: <20240815131854.872039764@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240815131852.063866671@linuxfoundation.org> References: <20240815131852.063866671@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li commit f9ca51596bbfd0f9c386dd1c613c394c78d9e5e6 upstream. The syzbot constructs a directory that has no dirblock but is non-inline, i.e. the first directory block is a hole. And no errors are reported when creating files in this directory in the following flow. ext4_mknod ... ext4_add_entry // Read block 0 ext4_read_dirblock(dir, block, DIRENT) bh = ext4_bread(NULL, inode, block, 0) if (!bh && (type == INDEX || type == DIRENT_HTREE)) // The first directory block is a hole // But type == DIRENT, so no error is reported. After that, we get a directory block without '.' and '..' but with a valid dentry. This may cause some code that relies on dot or dotdot (such as make_indexed_dir()) to crash. Therefore when ext4_read_dirblock() finds that the first directory block is a hole report that the filesystem is corrupted and return an error to avoid loading corrupted data from disk causing something bad. Reported-by: syzbot+ae688d469e36fb5138d0@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ae688d469e36fb5138d0 Fixes: 4e19d6b65fb4 ("ext4: allow directory holes") Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://patch.msgid.link/20240702132349.2600605-3-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/namei.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -134,10 +134,11 @@ static struct buffer_head *__ext4_read_d return bh; } - if (!bh && (type == INDEX || type == DIRENT_HTREE)) { + /* The first directory block must not be a hole. */ + if (!bh && (type == INDEX || type == DIRENT_HTREE || block == 0)) { ext4_error_inode(inode, func, line, block, - "Directory hole found for htree %s block", - (type == INDEX) ? "index" : "leaf"); + "Directory hole found for htree %s block %u", + (type == INDEX) ? "index" : "leaf", block); return ERR_PTR(-EFSCORRUPTED); } if (!bh) @@ -2850,10 +2851,7 @@ bool ext4_empty_dir(struct inode *inode) EXT4_ERROR_INODE(inode, "invalid size"); return true; } - /* The first directory block must not be a hole, - * so treat it as DIRENT_HTREE - */ - bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE); + bh = ext4_read_dirblock(inode, 0, EITHER); if (IS_ERR(bh)) return true; @@ -3425,10 +3423,7 @@ static struct buffer_head *ext4_get_firs struct ext4_dir_entry_2 *de; unsigned int offset; - /* The first directory block must not be a hole, so - * treat it as DIRENT_HTREE - */ - bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE); + bh = ext4_read_dirblock(inode, 0, EITHER); if (IS_ERR(bh)) { *retval = PTR_ERR(bh); return NULL;