From adcbe6e7b26bce6295835b796657655aa5385b12 Mon Sep 17 00:00:00 2001
From: Nicolas Pouillard <nicolas.pouillard@gmail.com>
Date: Mon, 5 Sep 2016 17:04:06 +0200
Subject: [PATCH] gpg/decode/parse_subpackets: parse subpacket length according
 to RFC

---
 trezor_agent/gpg/decode.py | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/trezor_agent/gpg/decode.py b/trezor_agent/gpg/decode.py
index d69050c..ded5c98 100644
--- a/trezor_agent/gpg/decode.py
+++ b/trezor_agent/gpg/decode.py
@@ -25,10 +25,17 @@ def parse_subpackets(s):
 
     while True:
         try:
-            subpacket_len = s.readfmt('B')
+            first = s.readfmt('B')
         except EOFError:
             break
 
+        if first < 192:
+            subpacket_len = first
+        elif first < 255:
+            subpacket_len = ((first - 192) << 8) + s.readfmt('B') + 192
+        else:  # first == 255
+            subpacket_len = s.readfmt('>L')
+
         subpackets.append(s.read(subpacket_len))
 
     return subpackets