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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index 95cb6970c3eafc87bbe1d10a66481315e3bd3241..7b72b7dd8906b8b6c6e6b1d848f881969630b839 100644 (file)
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -1487,6 +1487,15 @@ reread:
        }
        inode->i_generation = iinfo->i_unique;
 
+       /*
+        * Sanity check length of allocation descriptors and extended attrs to
+        * avoid integer overflows
+        */
+       if (iinfo->i_lenEAttr > bs || iinfo->i_lenAlloc > bs)
+               goto out;
+       /* Now do exact checks */
+       if (udf_file_entry_alloc_offset(inode) + iinfo->i_lenAlloc > bs)
+               goto out;
        /* Sanity checks for files in ICB so that we don't get confused later */
        if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
                /*