[PATCH 3.4 133/146] udf: Check length of extended attributes and allocation descriptors

lizf
2015-09-15T09:12:51Z

From: Jan Kara <jack@suse.cz>

3.4.109-rc1 review patch. If anyone has any objections, please let me know.

------------------

commit 23b133bdc452aa441fcb9b82cbf6dd05cfd342d0 upstream.

Check length of extended attributes and allocation descriptors when
loading inodes from disk. Otherwise corrupted filesystems could confuse
the code and make the kernel oops.

Reported-by: Carl Henrik Lunde <chlunde@ping.uio.no>
Signed-off-by: Jan Kara <jack@suse.cz>
[lizf: Backported to 3.4:
- call make_bad_inode() and then return
- relace bs with inode->i_sb->s_blocksize]
Signed-off-by: Zefan Li <lizefan@huawei.com>
---
fs/udf/inode.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 8053ee7..330ec8c 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1392,6 +1392,19 @@ static void udf_fill_inode(struct inode *inode, struct buffer_head *bh)
iinfo->i_lenEAttr;
}

+ /*
+ * Sanity check length of allocation descriptors and extended attrs to
+ * avoid integer overflows
+ */
+ if (iinfo->i_lenEAttr > inode->i_sb->s_blocksize || iinfo->i_lenAlloc > inode->i_sb->s_blocksize) {
+ make_bad_inode(inode);
+ return;
+ }
+ /* Now do exact checks */
+ if (udf_file_entry_alloc_offset(inode) + iinfo->i_lenAlloc > inode->i_sb->s_blocksize) {
+ make_bad_inode(inode);
+ return;
+ }
/* Sanity checks for files in ICB so that we don't get confused later */
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
/*
--
1.9.1