From b87d1a00d3eb7fb1eba6e7db2e26342724c0410e Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Mon, 8 Jan 2007 06:59:28 +0100 Subject: [PATCH] ext2: skip pages past number of blocks in ext2_find_entry (CVE-2006-6054) This one was pointed out on the MOKB site: http://kernelfun.blogspot.com/2006/11/mokb-09-11-2006-linux-26x-ext2checkpage.html If a directory's i_size is corrupted, ext2_find_entry() will keep processing pages until the i_size is reached, even if there are no more blocks associated with the directory inode. This patch puts in some minimal sanity-checking so that we don't keep checking pages (and issuing errors) if we know there can be no more data to read, based on the block count of the directory inode. This is somewhat similar in approach to the ext3 patch I sent earlier this year. Signed-off-by: Eric Sandeen Signed-off-by: Adrian Bunk --- fs/ext2/dir.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c index b3dbd716cd3a..8a27dcc096b5 100644 --- a/fs/ext2/dir.c +++ b/fs/ext2/dir.c @@ -369,6 +369,14 @@ struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir, } if (++n >= npages) n = 0; + /* next page is past the blocks we've got */ + if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) { + ext2_error(dir->i_sb, __FUNCTION__, + "dir %lu size %lld exceeds block count %llu", + dir->i_ino, dir->i_size, + (unsigned long long)dir->i_blocks); + goto out; + } } while (n != start); out: return NULL; -- 2.39.5