agent: Create and use Token entries to track the display s/n.

* agent/findkey.c (agent_write_private_key): Add arg dispserialno and
update the token.
(agent_write_shadow_key): Add arg dispserialno and adjust all callers.
--

GnuPG-bug-id: 6135

Note that this has been forward ported from 2.2

agent/agent.h

@@ -452,10 +452,12 @@ void start_command_handler_ssh (ctrl_t, gnupg_fd_t);
 /*-- findkey.c --*/
 gpg_error_t agent_modify_description (const char *in, const char *comment,
                                       const gcry_sexp_t key, char **result);
-int agent_write_private_key (const unsigned char *grip,
+gpg_error_t agent_write_private_key (const unsigned char *grip,
-                             const void *buffer, size_t length, int force,
+                                     const void *buffer, size_t length,
-                             const char *serialno, const char *keyref,
+                                     int force,
-                             time_t timestamp);
+                                     const char *serialno, const char *keyref,
+                                     const char *dispserialno,
+                                     time_t timestamp);
 gpg_error_t agent_key_from_file (ctrl_t ctrl,
                                  const char *cache_nonce,
                                  const char *desc_text,
@@ -587,7 +589,8 @@ gpg_error_t s2k_hash_passphrase (const char *passphrase, int hashalgo,
                                  unsigned char *key, size_t keylen);
 gpg_error_t agent_write_shadow_key (const unsigned char *grip,
                                     const char *serialno, const char *keyid,
-                                    const unsigned char *pkbuf, int force);
+                                    const unsigned char *pkbuf, int force,
+                                    const char *dispserialno);
 
 
 /*-- trustlist.c --*/

agent/command-ssh.c

@@ -2432,9 +2432,14 @@ card_key_available (ctrl_t ctrl, const struct card_key_info_s *keyinfo,
   hex2bin (keyinfo->keygrip, grip, sizeof (grip));
   if ( agent_key_available (grip) )
     {
+      char *dispserialno;
+
       /* (Shadow)-key is not available in our key storage.  */
+      agent_card_getattr (ctrl, "$DISPSERIALNO", &dispserialno,
+                          keyinfo->keygrip);
       err = agent_write_shadow_key (grip, keyinfo->serialno,
-                                    keyinfo->idstr, pkbuf, 0);
+                                    keyinfo->idstr, pkbuf, 0, dispserialno);
+      xfree (dispserialno);
       if (err)
         {
           xfree (pkbuf);
@@ -3282,7 +3287,7 @@ ssh_identity_register (ctrl_t ctrl, ssh_key_type_spec_t *spec,
   /* Store this key to our key storage.  We do not store a creation
    * timestamp because we simply do not know.  */
   err = agent_write_private_key (key_grip_raw, buffer, buffer_n, 0,
-                                 NULL, NULL, 0);
+                                 NULL, NULL, NULL, 0);
   if (err)
     goto out;
 

agent/command.c

@@ -1359,7 +1359,14 @@ cmd_readkey (assuan_context_t ctx, char *line)
       if (agent_key_available (grip))
         {
           /* (Shadow)-key is not available in our key storage.  */
-          rc = agent_write_shadow_key (grip, serialno, keyid, pkbuf, 0);
+          char *dispserialno;
+          char hexgrip[40+1];
+
+          bin2hex (grip, 20, hexgrip);
+          agent_card_getattr (ctrl, "$DISPSERIALNO", &dispserialno, hexgrip);
+          rc = agent_write_shadow_key (grip, serialno, keyid, pkbuf, 0,
+                                       dispserialno);
+          xfree (dispserialno);
           if (rc)
             goto leave;
         }
@@ -2916,11 +2923,11 @@ cmd_import_key (assuan_context_t ctx, char *line)
                            ctrl->s2k_count);
       if (!err)
         err = agent_write_private_key (grip, finalkey, finalkeylen, force,
-                                       NULL, NULL, opt_timestamp);
+                                       NULL, NULL, NULL, opt_timestamp);
     }
   else
-    err = agent_write_private_key (grip, key, realkeylen, force, NULL, NULL,
+    err = agent_write_private_key (grip, key, realkeylen, force,
-                                   opt_timestamp);
+                                   NULL, NULL, NULL, opt_timestamp);
 
  leave:
   gcry_sexp_release (openpgp_sexp);

agent/cvt-openpgp.c

@@ -1148,7 +1148,7 @@ convert_from_openpgp_native (ctrl_t ctrl,
                               &protectedkey, &protectedkeylen,
                               ctrl->s2k_count))
             agent_write_private_key (grip, protectedkey, protectedkeylen, 1,
-                                     NULL, NULL, 0);
+                                     NULL, NULL, NULL, 0);
           xfree (protectedkey);
         }
       else
@@ -1157,7 +1157,7 @@ convert_from_openpgp_native (ctrl_t ctrl,
           agent_write_private_key (grip,
                                    *r_key,
                                    gcry_sexp_canon_len (*r_key, 0, NULL,NULL),
-                                   1, NULL, NULL, 0);
+                                   1, NULL, NULL, NULL, 0);
         }
     }
 

agent/divert-tpm2.c

@@ -50,7 +50,7 @@ agent_write_tpm2_shadow_key (ctrl_t ctrl, const unsigned char *grip,
 
   len = gcry_sexp_canon_len (shdkey, 0, NULL, NULL);
   err = agent_write_private_key (grip, shdkey, len, 1 /*force*/,
-                                 NULL, NULL, 0);
+                                 NULL, NULL, NULL, 0);
   xfree (shdkey);
   if (err)
     log_error ("error writing key: %s\n", gpg_strerror (err));

agent/findkey.c

@@ -84,12 +84,13 @@ linefeed_to_percent0A (const char *string)
  * storage.  With FORCE passed as true an existing key with the given
  * GRIP will get overwritten.  If SERIALNO and KEYREF are given a
  * Token line is added to the key if the extended format is used.  If
- * TIMESTAMP is not zero and the key doies not yet exists it will be
+ * TIMESTAMP is not zero and the key does not yet exists it will be
  * recorded as creation date.  */
-int
+gpg_error_t
 agent_write_private_key (const unsigned char *grip,
                          const void *buffer, size_t length, int force,
                          const char *serialno, const char *keyref,
+                         const char *dispserialno,
                          time_t timestamp)
 {
   gpg_error_t err;
@@ -100,7 +101,10 @@ agent_write_private_key (const unsigned char *grip,
   nvc_t pk = NULL;
   gcry_sexp_t key = NULL;
   int remove = 0;
+  char *token0 = NULL;
   char *token = NULL;
+  char *dispserialno_buffer = NULL;
+  char **tokenfields = NULL;
 
   bin2hex (grip, 20, hexgrip);
   strcpy (hexgrip+40, ".key");
@@ -225,19 +229,34 @@ agent_write_private_key (const unsigned char *grip,
     {
       nve_t item;
       const char *s;
+      size_t token0len;
 
-      token = strconcat (serialno, " ", keyref, NULL);
+      if (dispserialno)
-      if (!token)
+        {
+          /* Escape the DISPSERIALNO.  */
+          dispserialno_buffer = percent_plus_escape (dispserialno);
+          if (!dispserialno_buffer)
+            {
+              err = gpg_error_from_syserror ();
+              goto leave;
+            }
+          dispserialno = dispserialno_buffer;
+        }
+
+      token0 = strconcat (serialno, " ", keyref, NULL);
+      if (token0)
+        token = strconcat (token0, " - ", dispserialno? dispserialno:"-", NULL);
+      if (!token0 || !token)
         {
           err = gpg_error_from_syserror ();
           goto leave;
         }
 
-      /* fixme: the strcmp should compare only the first two strings.  */
+      token0len = strlen (token0);
       for (item = nvc_lookup (pk, "Token:");
            item;
            item = nve_next_value (item, "Token:"))
-        if ((s = nve_value (item)) && !strcmp (s, token))
+        if ((s = nve_value (item)) && !strncmp (s, token0, token0len))
           break;
       if (!item)
         {
@@ -248,6 +267,23 @@ agent_write_private_key (const unsigned char *grip,
           if (err)
             goto leave;
         }
+      else
+        {
+          /* Token exists: Update the display s/n.  It may have
+           * changed due to changes in a newer software version.  */
+          if (s && (tokenfields = strtokenize (s, " \t\n"))
+              && tokenfields[0] && tokenfields[1] && tokenfields[2]
+              && tokenfields[3]
+              && !strcmp (tokenfields[3], dispserialno))
+            ; /* No need to update Token entry.  */
+          else
+            {
+              err = nve_set (item, token);
+              if (err)
+                goto leave;
+            }
+        }
+
     }
 
   /* If a timestamp has been supplied and the key is new, write a
@@ -300,12 +336,15 @@ agent_write_private_key (const unsigned char *grip,
 
  leave:
   es_fclose (fp);
-  if (remove)
+  if (remove && fname)
     gnupg_remove (fname);
   xfree (fname);
+  xfree (token);
+  xfree (token0);
+  xfree (dispserialno_buffer);
+  xfree (tokenfields);
   gcry_sexp_release (key);
   nvc_release (pk);
-  xfree (token);
   return err;
 }
 
@@ -1794,7 +1833,8 @@ agent_delete_key (ctrl_t ctrl, const char *desc_text,
 gpg_error_t
 agent_write_shadow_key (const unsigned char *grip,
                         const char *serialno, const char *keyid,
-                        const unsigned char *pkbuf, int force)
+                        const unsigned char *pkbuf, int force,
+                        const char *dispserialno)
 {
   gpg_error_t err;
   unsigned char *shadow_info;
@@ -1821,7 +1861,8 @@ agent_write_shadow_key (const unsigned char *grip,
     }
 
   len = gcry_sexp_canon_len (shdkey, 0, NULL, NULL);
-  err = agent_write_private_key (grip, shdkey, len, force, serialno, keyid, 0);
+  err = agent_write_private_key (grip, shdkey, len, force,
+                                 serialno, keyid, dispserialno, 0);
   xfree (shdkey);
   if (err)
     log_error ("error writing key: %s\n", gpg_strerror (err));

agent/genkey.c

@@ -67,7 +67,8 @@ store_key (gcry_sexp_t private, const char *passphrase, int force,
       buf = p;
     }
 
-  rc = agent_write_private_key (grip, buf, len, force, NULL, NULL, timestamp);
+  rc = agent_write_private_key (grip, buf, len, force,
+                                NULL, NULL, NULL, timestamp);
   xfree (buf);
   return rc;
 }

agent/learncard.c

@@ -408,7 +408,15 @@ agent_handle_learn (ctrl_t ctrl, int send, void *assuan_context, int force)
           goto leave;
         }
 
-      rc = agent_write_shadow_key (grip, serialno, item->id, pubkey, force);
+      {
+        char *dispserialno;
+
+        agent_card_getattr (ctrl, "$DISPSERIALNO", &dispserialno,
+                            item->hexgrip);
+        rc = agent_write_shadow_key (grip, serialno, item->id, pubkey, force,
+                                     dispserialno);
+        xfree (dispserialno);
+      }
       xfree (pubkey);
       if (rc)
         goto leave;

agent/pksign.c

@@ -372,8 +372,15 @@ agent_pksign_do (ctrl_t ctrl, const char *cache_nonce,
             }
 
           if (keyref)
-            agent_write_shadow_key (ctrl->keygrip, serialno, keyref, pkbuf, 0);
+            {
+              char *dispserialno;
 
+              agent_card_getattr (ctrl, "$DISPSERIALNO", &dispserialno,
+                                  hexgrip);
+              agent_write_shadow_key (ctrl->keygrip, serialno, keyref, pkbuf,
+                                      0, dispserialno);
+              xfree (dispserialno);
+            }
           algo = get_pk_algo_from_key (s_pkey);
 
           xfree (serialno);

agent/protect-tool.c

@@ -813,11 +813,11 @@ agent_askpin (ctrl_t ctrl,
 
 /* Replacement for the function in findkey.c.  Here we write the key
  * to stdout. */
-int
+gpg_error_t
 agent_write_private_key (const unsigned char *grip,
                          const void *buffer, size_t length, int force,
                          const char *serialno, const char *keyref,
-                         time_t timestamp)
+                         const char *dispserialno, time_t timestamp)
 {
   char hexgrip[40+4+1];
   char *p;
@@ -826,6 +826,7 @@ agent_write_private_key (const unsigned char *grip,
   (void)serialno;
   (void)keyref;
   (void)timestamp;
+  (void)dispserialno;
 
   bin2hex (grip, 20, hexgrip);
   strcpy (hexgrip+40, ".key");