From d8adb9cef7e406a9a82881695097c702bc98422f Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Sat, 10 Feb 2007 01:45:06 -0800 Subject: [PATCH] [PATCH] ext2: skip pages past number of blocks in ext2_find_entry 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: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ext2/dir.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c index 0b02ba9642d2..e89bfc8cf957 100644 --- a/fs/ext2/dir.c +++ b/fs/ext2/dir.c @@ -368,6 +368,14 @@ 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;