[PATCH] scd: do_decipher change for OpenPGPcard v3.0

[NIIBE Yutaka]

Hello,

This is the change required by current draft of OpenPGPcard v3.0
specification.

The decoration was not needed (for me), but, it would make sense,
perhaps.

I'm going to change Gnuk so that it will support both (w/ decoration
or w/out decoration).

diff --git a/scd/app-openpgp.c b/scd/app-openpgp.c
index 8520231..0e751e0 100644
--- a/scd/app-openpgp.c
+++ b/scd/app-openpgp.c
@@ -4046,6 +4046,7 @@ do_decipher (app_t app, const char *keyidstr,
   int exmode, le_value;
   unsigned char *fixbuf = NULL;
   int padind = 0;
+  int fixuplen = 0;

   if (!keyidstr || !*keyidstr || !indatalen)
     return gpg_error (GPG_ERR_INV_VALUE);
@@ -4092,8 +4093,6 @@ do_decipher (app_t app, const char *keyidstr,

   if (app->app_local->keyattr[1].key_type == KEY_TYPE_RSA)
     {
-      int fixuplen;
-
       /* We might encounter a couple of leading zeroes in the
          cryptogram.  Due to internal use of MPIs these leading zeroes
          are stripped.  However the OpenPGP card expects exactly 128
@@ -4146,7 +4145,26 @@ do_decipher (app_t app, const char *keyidstr,
         }
     }
   else if (app->app_local->keyattr[1].key_type == KEY_TYPE_ECC)
-    padind = -1;
+    {
+      fixuplen = 7;
+      fixbuf = xtrymalloc (fixuplen + indatalen);
+      if (!fixbuf)
+        return gpg_error_from_syserror ();
+
+      /* Build 'Cipher DO' */
+      fixbuf[0] = '\xa6';
+      fixbuf[1] = (char)(indatalen+5);
+      fixbuf[2] = '\x7f';
+      fixbuf[3] = '\x49';
+      fixbuf[4] = (char)(indatalen+2);
+      fixbuf[5] = '\x86';
+      fixbuf[6] = (char)indatalen;
+      memcpy (fixbuf+fixuplen, indata, indatalen);
+      indata = fixbuf;
+      indatalen = fixuplen + indatalen;
+
+      padind = -1;
+    }
   else
     return gpg_error (GPG_ERR_INV_VALUE);

--