Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932508Ab1DLOku (ORCPT ); Tue, 12 Apr 2011 10:40:50 -0400 Received: from kroah.org ([198.145.64.141]:57885 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932468Ab1DLOi6 (ORCPT ); Tue, 12 Apr 2011 10:38:58 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Tue Apr 12 07:35:58 2011 Message-Id: <20110412143558.550111079@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Tue, 12 Apr 2011 07:35:28 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Phillip Lougher Subject: [099/105] Squashfs: handle corruption of directory structure In-Reply-To: <20110412143613.GA19478@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2859 Lines: 97 2.6.38-stable review patch. If anyone has any objections, please let us know. ------------------ From: Phillip Lougher commit 44cff8a9ee8a974f9e931df910688e7fc1f0b0f9 upstream. Handle the rare case where a directory metadata block is uncompressed and corrupted, leading to a kernel oops in directory scanning (memcpy). Normally corruption is detected at the decompression stage and dealt with then, however, this will not happen if: - metadata isn't compressed (users can optionally request no metadata compression), or - the compressed metadata block was larger than the original, in which case the uncompressed version was used, or - the data was corrupt after decompression This patch fixes this by adding some sanity checks against known maximum values. Signed-off-by: Phillip Lougher Signed-off-by: Greg Kroah-Hartman --- fs/squashfs/dir.c | 9 +++++++++ fs/squashfs/namei.c | 12 ++++++++++++ 2 files changed, 21 insertions(+) --- a/fs/squashfs/dir.c +++ b/fs/squashfs/dir.c @@ -172,6 +172,11 @@ static int squashfs_readdir(struct file length += sizeof(dirh); dir_count = le32_to_cpu(dirh.count) + 1; + + /* dir_count should never be larger than 256 */ + if (dir_count > 256) + goto failed_read; + while (dir_count--) { /* * Read directory entry. @@ -183,6 +188,10 @@ static int squashfs_readdir(struct file size = le16_to_cpu(dire->size) + 1; + /* size should never be larger than SQUASHFS_NAME_LEN */ + if (size > SQUASHFS_NAME_LEN) + goto failed_read; + err = squashfs_read_metadata(inode->i_sb, dire->name, &block, &offset, size); if (err < 0) --- a/fs/squashfs/namei.c +++ b/fs/squashfs/namei.c @@ -176,6 +176,11 @@ static struct dentry *squashfs_lookup(st length += sizeof(dirh); dir_count = le32_to_cpu(dirh.count) + 1; + + /* dir_count should never be larger than 256 */ + if (dir_count > 256) + goto data_error; + while (dir_count--) { /* * Read directory entry. @@ -187,6 +192,10 @@ static struct dentry *squashfs_lookup(st size = le16_to_cpu(dire->size) + 1; + /* size should never be larger than SQUASHFS_NAME_LEN */ + if (size > SQUASHFS_NAME_LEN) + goto data_error; + err = squashfs_read_metadata(dir->i_sb, dire->name, &block, &offset, size); if (err < 0) @@ -228,6 +237,9 @@ exit_lookup: d_add(dentry, inode); return ERR_PTR(0); +data_error: + err = -EIO; + read_failure: ERROR("Unable to read directory block [%llx:%x]\n", squashfs_i(dir)->start + msblk->directory_table, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/