From 6e7bb818aeabcafe5f9872c7cbd97ef8edaa463a Mon Sep 17 00:00:00 2001
From: Pol Henarejos <pol.henarejos@cttc.es>
Date: Sun, 12 Jul 2026 22:47:06 +0200
Subject: [PATCH] C4 rejects payloads longer than four bytes, preventing
 retry-counter corruption.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>
---
 src/openpgp/cmd_put_data.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/openpgp/cmd_put_data.c b/src/openpgp/cmd_put_data.c
index 5837082..2134a4c 100644
--- a/src/openpgp/cmd_put_data.c
+++ b/src/openpgp/cmd_put_data.c
@@ -46,6 +46,9 @@ int cmd_put_data(void) {
         return SW_SECURITY_STATUS_NOT_SATISFIED();
     }
     if (fid == EF_PW_STATUS) {
+        if (apdu.nc > 4) {
+            return SW_WRONG_DATA();
+        }
         fid = EF_PW_PRIV;
         if (apdu.nc == 0) {
             return SW_WRONG_LENGTH();