From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:46310 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753506AbeDVN6j (ORCPT ); Sun, 22 Apr 2018 09:58:39 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Theodore Tso , stable@kernel.org Subject: [PATCH 4.16 097/196] ext4: add bounds checking to ext4_xattr_find_entry() Date: Sun, 22 Apr 2018 15:51:57 +0200 Message-Id: <20180422135109.289326160@linuxfoundation.org> In-Reply-To: <20180422135104.278511750@linuxfoundation.org> References: <20180422135104.278511750@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit 9496005d6ca4cf8f5ee8f828165a8956872dc59d upstream. Add some paranoia checks to make sure we don't stray beyond the end of the valid memory region containing ext4 xattr entries while we are scanning for a match. Also rename the function to xattr_find_entry() since it is static and thus only used in fs/ext4/xattr.c Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/xattr.c | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -276,18 +276,22 @@ errout: __xattr_check_inode((inode), (header), (end), __func__, __LINE__) static int -ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, - const char *name, int sorted) +xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry, + void *end, int name_index, const char *name, int sorted) { - struct ext4_xattr_entry *entry; + struct ext4_xattr_entry *entry, *next; size_t name_len; int cmp = 1; if (name == NULL) return -EINVAL; name_len = strlen(name); - entry = *pentry; - for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { + for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) { + next = EXT4_XATTR_NEXT(entry); + if ((void *) next >= end) { + EXT4_ERROR_INODE(inode, "corrupted xattr entries"); + return -EFSCORRUPTED; + } cmp = name_index - entry->e_name_index; if (!cmp) cmp = name_len - entry->e_name_len; @@ -509,6 +513,7 @@ ext4_xattr_block_get(struct inode *inode struct buffer_head *bh = NULL; struct ext4_xattr_entry *entry; size_t size; + void *end; int error; struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode); @@ -530,7 +535,8 @@ ext4_xattr_block_get(struct inode *inode goto cleanup; ext4_xattr_block_cache_insert(ea_block_cache, bh); entry = BFIRST(bh); - error = ext4_xattr_find_entry(&entry, name_index, name, 1); + end = bh->b_data + bh->b_size; + error = xattr_find_entry(inode, &entry, end, name_index, name, 1); if (error) goto cleanup; size = le32_to_cpu(entry->e_value_size); @@ -579,7 +585,7 @@ ext4_xattr_ibody_get(struct inode *inode if (error) goto cleanup; entry = IFIRST(header); - error = ext4_xattr_find_entry(&entry, name_index, name, 0); + error = xattr_find_entry(inode, &entry, end, name_index, name, 0); if (error) goto cleanup; size = le32_to_cpu(entry->e_value_size); @@ -1808,8 +1814,8 @@ ext4_xattr_block_find(struct inode *inod bs->s.first = BFIRST(bs->bh); bs->s.end = bs->bh->b_data + bs->bh->b_size; bs->s.here = bs->s.first; - error = ext4_xattr_find_entry(&bs->s.here, i->name_index, - i->name, 1); + error = xattr_find_entry(inode, &bs->s.here, bs->s.end, + i->name_index, i->name, 1); if (error && error != -ENODATA) goto cleanup; bs->s.not_found = error; @@ -2168,8 +2174,8 @@ int ext4_xattr_ibody_find(struct inode * if (error) return error; /* Find the named attribute. */ - error = ext4_xattr_find_entry(&is->s.here, i->name_index, - i->name, 0); + error = xattr_find_entry(inode, &is->s.here, is->s.end, + i->name_index, i->name, 0); if (error && error != -ENODATA) return error; is->s.not_found = error;