ihex: Check if zero-length record is at the end of the blob

When verifying the validity of IHEX file we need to make sure that
zero-length record we found is located at the end of the file. Not
doing that could result in an invalid file with a bogus zero-length in
the middle short-circuiting the check and being reported as valid.

Cc: Chris Healy <[e-mail]>
Cc: Kyle McMartin <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: Masahiro Yamada <[e-mail]>
Cc: David Woodhouse <[e-mail]>
Cc: Greg Kroah-Hartman <[e-mail]>
Cc: linux-kernel <[e-mail]>
Signed-off-by: Andrey Smirnov <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

include/linux/ihex.h

···
 
 	for (; rec <= end; rec = __ihex_next_binrec(rec)) {
 		/* Zero length marks end of records */
-		if (!be16_to_cpu(rec->len))
+		if (rec == end && !be16_to_cpu(rec->len))
 			return 0;
 	}
 	return -EINVAL;