Messages in this thread Patch in this message | | | Date | Wed, 10 Jan 2007 17:27:21 -0800 | From | Chris Wright <> | Subject | [PATCH] ext2: skip pages past number of blocks in ext2_find_entry (CVE-2006-6054) |
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This one looks like it fell through the cracks, it's in 2.6.19.2 but not upstream yet.
thanks, -chris -- Subject: [PATCH] ext2: skip pages past number of blocks in ext2_find_entry (CVE-2006-6054) From: Eric Sandeen <sandeen@redhat.com>
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 <sandeen@redhat.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> --- Not upstream yet
fs/ext2/dir.c | 8 ++++++++ 1 file changed, 8 insertions(+)
--- linux-2.6.19.1.orig/fs/ext2/dir.c +++ linux-2.6.19.1/fs/ext2/dir.c @@ -368,6 +368,14 @@ struct ext2_dir_entry_2 * ext2_find_entr } 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; - 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/
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