Yubico and GnuPG interpretate the standard in different ways. While Yubico follows strictly the spec and expects the TAG encapsulating the output of GET_DATA, GnuPG expects consecutive DO in the response.

A possible workaround is to detect whether sub-DO are called (GnuPG) or management AID is called (Yubico).

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

src/openpgp/cmd_get_data.c

@@ -37,6 +37,9 @@ int cmd_get_data() {
         select_file(ef);
     }
     if (ef->data) {
+        if (fid == EF_PW_STATUS || fid == EF_HIST_BYTES || fid == EF_FULL_AID || fid == EF_SEC_TPL) {
+            is_gpg = true;
+        }
         uint16_t fids[] = { 1, fid };
         uint16_t data_len = parse_do(fids, 1);
         uint8_t *p = NULL;
@@ -58,8 +61,42 @@ int cmd_get_data() {
                 res_APDU_size -= dec;
             }
         }
-        //if (apdu.ne > data_len)
-        //    apdu.ne = data_len;
+        if (is_gpg == false) {
+            uint8_t off = 2;
+            if (P1(apdu) > 0x0) {
+                off++;
+            }
+            if (data_len >= 128) {
+                off++;
+            }
+            if (data_len >= 256) {
+                off++;
+            }
+            memmove(res_APDU + off, res_APDU, data_len);
+            off = 0;
+            if (P1(apdu) > 0x0) {
+                res_APDU[off++] = P1(apdu);
+                res_APDU[off++] = P2(apdu);
+            }
+            else {
+                res_APDU[off++] = P2(apdu);
+            }
+            if (data_len >= 256) {
+                res_APDU[off++] = 0x82;
+                res_APDU[off++] = (data_len >> 8) & 0xff;
+                res_APDU[off++] = data_len & 0xff;
+            }
+            else if (data_len >= 128) {
+                res_APDU[off++] = 0x81;
+                res_APDU[off++] = data_len;
+            }
+            else {
+                res_APDU[off++] = data_len;
+            }
+            res_APDU_size += off;
+        }
+        // if (apdu.ne > data_len)
+        //     apdu.ne = data_len;
     }
     return SW_OK();
 }

src/openpgp/files.c

@@ -17,6 +17,8 @@
 
 #include "files.h"
 
+bool is_gpg = true;
+
 extern const uint8_t openpgp_aid[];
 extern const uint8_t openpgp_aid_full[];
 

src/openpgp/files.h

@@ -163,4 +163,6 @@
 
 #define EF_DEV_CONF     0x1122
 
+extern bool is_gpg;
+
 #endif

src/openpgp/management.c

@@ -145,6 +145,7 @@ int man_process_apdu() {
     }
     for (const cmd_t *cmd = cmds; cmd->ins != 0x00; cmd++) {
         if (cmd->ins == INS(apdu)) {
+            is_gpg = false;
             int r = cmd->cmd_handler();
             return r;
         }