From a14b5f7b5fbde1aec5c5359ded808fd056d5c38a Mon Sep 17 00:00:00 2001
From: Ave <ave@ave.zone>
Date: Tue, 29 Dec 2020 19:24:44 +0300
Subject: [PATCH] emrtd: Employ a workaround for data length of 0x80

This is to make US passport hashes read properly.
https://wf.lavatech.top/ave-but-random/emrtd-data-quirks#EF_SOD
---
 client/src/cmdhfemrtd.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/client/src/cmdhfemrtd.c b/client/src/cmdhfemrtd.c
index 6b966cfad..fa9c936e9 100644
--- a/client/src/cmdhfemrtd.c
+++ b/client/src/cmdhfemrtd.c
@@ -217,6 +217,11 @@ static int emrtd_get_asn1_data_length(uint8_t *datain, int datainlen, int offset
     PrintAndLogEx(DEBUG, "asn1 datalength, lenfield: %02X", lenfield);
     if (lenfield <= 0x7f) {
         return lenfield;
+    } else if (lenfield == 0x80) {
+        // TODO: 0x80 means indeterminate.
+        // Giving rest of the file is a workaround, nothing more, nothing less.
+        // More at https://letsencrypt.org/docs/a-warm-welcome-to-asn1-and-der/
+        return datainlen;
     } else if (lenfield == 0x81) {
         return ((int) * (datain + offset + 1));
     } else if (lenfield == 0x82) {
@@ -231,7 +236,7 @@ static int emrtd_get_asn1_field_length(uint8_t *datain, int datainlen, int offse
     PrintAndLogEx(DEBUG, "asn1 fieldlength, datain: %s", sprint_hex_inrow(datain, datainlen));
     int lenfield = (int) * (datain + offset);
     PrintAndLogEx(DEBUG, "asn1 fieldlength, lenfield: %02X", lenfield);
-    if (lenfield <= 0x7F) {
+    if (lenfield <= 0x80) {
         return 1;
     } else if (lenfield == 0x81) {
         return 2;