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

From: Andrey Smirnov
Date: Fri Dec 21 2018 - 02:28:38 EST

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 <cphealy@xxxxxxxxx>
Cc: Kyle McMartin <kyle@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: linux-kernel <linux-kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
include/linux/ihex.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/ihex.h b/include/linux/ihex.h
index 9c701521176b..9130f307a420 100644
--- a/include/linux/ihex.h
+++ b/include/linux/ihex.h
@@ -49,7 +49,7 @@ static inline int ihex_validate_fw(const struct firmware *fw)

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;