udf: Check length of extended attributes and allocation descriptors

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>
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>

fs/udf/inode.c

@@ -1487,6 +1487,15 @@ static int udf_read_inode(struct inode *inode, bool hidden_inode)
 	}
 	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) {
 		/*