udf: Check length of extended attributes and allocation descriptors

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>
[bwh: Backported to 2.6.32: use make_bad_inode() instead of returning error]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
CVE-2015-4167

Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 26b7f31dc623cac3af2894126b6a90ce9884d172..b8d7a0e3aece9afe7ee1991c01cf0f79296de405 100644 (file)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1284,6 +1284,19 @@ 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 > bs || iinfo->i_lenAlloc > bs) {
+               make_bad_inode(inode);
+               return;
+       }
+       /* Now do exact checks */
+       if (udf_file_entry_alloc_offset(inode) + iinfo->i_lenAlloc > bs) {
+               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) {
                /*