2004-08-07 Moritz Schulte <moritz@g10code.com>

* command-ssh.c (ssh_key_to_sexp_buffer): New argument: comment;
	integrate into S-Exp.
	(ssh_identity_register): New argument: comment; pass to
	ssh_key_to_sexp_buffer().
	(ssh_handler_add_identity): Pass comment to
	ssh_identity_register().
	(ssh_identity_register): Allocate description dynamically, insert
	comment; new variable: description_length; removed variable: i.
	(data_sign): Do not calculate key grip for integration in
	description; removed variable: i.

	* findkey.c (modify_description): New function.
	(agent_key_from_file): New variables: comment, comment_sexp,
	comment_length, desc_text_modified; extract comment from S-Exp,
	pass modified version to unprotect().

agent/ChangeLog

@@ -1,3 +1,21 @@
+2004-08-07  Moritz Schulte  <moritz@g10code.com>
+
+	* command-ssh.c (ssh_key_to_sexp_buffer): New argument: comment;
+	integrate into S-Exp.
+	(ssh_identity_register): New argument: comment; pass to
+	ssh_key_to_sexp_buffer().
+	(ssh_handler_add_identity): Pass comment to
+	ssh_identity_register().
+	(ssh_identity_register): Allocate description dynamically, insert
+	comment; new variable: description_length; removed variable: i.
+	(data_sign): Do not calculate key grip for integration in
+	description; removed variable: i.
+
+	* findkey.c (modify_description): New function.
+	(agent_key_from_file): New variables: comment, comment_sexp,
+	comment_length, desc_text_modified; extract comment from S-Exp,
+	pass modified version to unprotect().
+	
 2004-07-30  Moritz Schulte  <moritz@g10code.com>
 
 	* command-ssh.c: Updated Libgpg-stream (more support for secure

agent/command-ssh.c

@@ -985,14 +985,7 @@ data_sign (CTRL ctrl, unsigned char **sig, size_t *sig_n)
   size_t sig_blob_n = 0;
   size_t bytes_read = 0;
   char description[] =
-    "Please provide the passphrase for key "
+    "Please provide the passphrase for key `%c':";
-    "`0123456789012345678901234567890123456789':";
-  char key_grip[41];
-  unsigned int i = 0;
-
-  for (i = 0; i < 20; i++)
-    sprintf (&key_grip[i * 2], "%02X", (unsigned char) ctrl->keygrip[i]);
-  strncpy (strchr (description, '0'), key_grip, 40);
 
   err = agent_pksign_do (ctrl, description, &signature_sexp, 0);
   if (err)
@@ -1174,7 +1167,8 @@ ssh_handler_sign_request (ctrl_t ctrl,
 }
 
 static gpg_err_code_t
-ssh_key_to_sexp_buffer (ssh_key_secret_t *key, const char *passphrase,
+ssh_key_to_sexp_buffer (ssh_key_secret_t *key,
+			const char *comment, const char *passphrase,
 			unsigned char **buffer, size_t *buffer_n)
 {
   gpg_err_code_t err = GPG_ERR_NO_ERROR;
@@ -1190,13 +1184,15 @@ ssh_key_to_sexp_buffer (ssh_key_secret_t *key, const char *passphrase,
 			 "  (d %m)"
 			 "  (p %m)"
 			 "  (q %m)"
-			 "  (u %m)))",
+			 "  (u %m))"
+			 " (comment %s))",
 			 key->material.rsa.n,
 			 key->material.rsa.e,
 			 key->material.rsa.d,
 			 key->material.rsa.p,
 			 key->material.rsa.q,
-			 key->material.rsa.u);
+			 key->material.rsa.u,
+			 comment ? comment : "");
   if (err)
     goto out;
 
@@ -1256,18 +1252,15 @@ get_passphrase (char *description, size_t passphrase_n, char *passphrase)
 }
 
 static gpg_err_code_t
-ssh_identity_register (ssh_key_secret_t *key, int ttl)
+ssh_identity_register (ssh_key_secret_t *key, const char *comment, int ttl)
 {
   gpg_err_code_t err = GPG_ERR_NO_ERROR;
   unsigned char key_grip_raw[21] = { 0 };
   unsigned char *buffer = NULL;
   unsigned int buffer_n = 0;
   char passphrase[100] = { 0 };
-  char description[] =
+  size_t description_length = 0;
-    "Please provide the passphrase, which should  "
+  char *description = NULL;
-    "be used for protecting the received secret key "
-    "`0123456789012345678901234567890123456789':";
-  unsigned int i = 0;
   char key_grip[41];
   int ret = 0;
 
@@ -1282,16 +1275,25 @@ ssh_identity_register (ssh_key_secret_t *key, int ttl)
   if (! ret)
     goto out;
 
-  for (i = 0; i < 20; i++)
+  description_length = 95 + (comment ? strlen (comment) : 0);
-    sprintf (&key_grip[i * 2], "%02X", key_grip_raw[i]);
+  description = malloc (description_length);
-  strncpy (strchr (description, '0'), key_grip, 40);
+  if (! description)
+    {
+      err = gpg_err_code_from_errno (errno);
+      goto out;
+    }
+  else
+    sprintf (description,
+	     "Please provide the passphrase, which should be used "
+	     "for protecting the received secret key `%s':",
+	     comment ? comment : "");
 
-  err = get_passphrase (description,
+  err = get_passphrase (description, sizeof (passphrase), passphrase);
-			sizeof (passphrase), passphrase);
+  free (description);
   if (err)
     goto out;
 
-  err = ssh_key_to_sexp_buffer (key, passphrase, &buffer, &buffer_n);
+  err = ssh_key_to_sexp_buffer (key, comment, passphrase, &buffer, &buffer_n);
   if (err)
     goto out;
 
@@ -1391,7 +1393,7 @@ ssh_handler_add_identity (ctrl_t ctrl,
 
   /* FIXME: are constraints used correctly?  */
 
-  err = ssh_identity_register (&key, death);
+  err = ssh_identity_register (&key, comment, death);
   if (err)
     goto out;
 

agent/findkey.c

@@ -136,6 +136,109 @@ try_unprotect_cb (struct pin_entry_info_s *pi)
 }
 
 
+/* Modify a Key description, replacing certain special format
+   characters.  */
+static int
+modify_description (const char *description,
+		    const char *comment, size_t comment_length,
+		    char **description_modified)
+{
+  size_t description_length = strlen (description);
+  size_t description_new_length = description_length;
+  gpg_error_t err = GPG_ERR_NO_ERROR;
+  char *description_new = NULL;
+  unsigned int i = 0, j = 0;
+  unsigned int special = 0;
+
+  /* Calculate length.  */
+  for (i = 0; i < description_length; i++)
+    {
+      if (description[i] == '%')
+	special = 1;
+      else
+	{
+	  if (special)
+	    {
+	      description_new_length -= 2;
+	      switch (description[i])
+		{
+		case 'c':
+		  /* Comment.  */
+		  description_new_length += comment_length;
+		  break;
+		  
+		case 'g':
+		  /* Key grip.  */
+		  description_new_length += 40;
+		  break;
+		  
+		case '%':
+		  description_new_length += 1;
+		  break;
+		}
+	      special = 0;
+	    }
+	}
+    }
+
+  /* Allocate.  */
+  description_new = malloc (description_new_length + 1);
+  if (! description_new)
+    {
+      err = gpg_error_from_errno (errno);
+      goto out;
+    }
+
+  /* Fill.  */
+  for (i = j = 0; i < description_length; i++)
+    {
+      if (description[i] == '%')
+	special = 1;
+      else
+	{
+	  if (special)
+	    {
+	      switch (description[i])
+		{
+		case 'c':
+		  /* Comment.  */
+		  if (comment)
+		    {
+		      strncpy (description_new + j, comment, comment_length);
+		      j += comment_length;
+		    }
+		  break;
+		  
+		case 'g':
+		  /* Key grip.  */
+		  /* FIXME */
+		  break;
+		  
+		case '%':
+		  description_new[j] = '%';
+		  j++;
+		  break;
+		}
+	      special = 0;
+	    }
+	  else
+	    {
+	      description_new[j] = description[i];
+	      j++;
+	    }
+	}
+    }
+  description_new[j] = 0;
+
+ out:
+
+  *description_modified = description_new;
+
+  return err;
+}
+
+  
+
 /* Unprotect the canconical encoded S-expression key in KEYBUF.  GRIP
    should be the hex encoded keygrip of that key to be used with the
    caching mechanism. DESC_TEXT may be set to override the default
@@ -220,6 +323,10 @@ agent_key_from_file (CTRL ctrl, const char *desc_text,
   gcry_sexp_t s_skey;
   char hexgrip[40+4+1];
   int got_shadow_info = 0;
+  const char *comment = NULL;
+  gcry_sexp_t comment_sexp = NULL;
+  char *desc_text_modified = NULL;
+  size_t comment_length = 0;
   
   *result = NULL;
   if (shadow_info)
@@ -264,12 +371,26 @@ agent_key_from_file (CTRL ctrl, const char *desc_text,
   xfree (fname);
   fclose (fp);
   xfree (buf);
+
   if (rc)
     {
       log_error ("failed to build S-Exp (off=%u): %s\n",
                  (unsigned int)erroff, gpg_strerror (rc));
       return rc;
     }
+
+  comment_sexp = gcry_sexp_find_token (s_skey, "comment", 0);
+  if (comment_sexp)
+    {
+      comment = gcry_sexp_nth_data (comment_sexp, 1, &comment_length);
+      if (! comment)
+	{
+	  rc = GPG_ERR_INV_SEXP;
+	  gcry_sexp_release (s_skey);
+	  return rc;
+	}
+    }
+
   len = gcry_sexp_sprint (s_skey, GCRYSEXP_FMT_CANON, NULL, 0);
   assert (len);
   buf = xtrymalloc (len);
@@ -288,10 +409,18 @@ agent_key_from_file (CTRL ctrl, const char *desc_text,
     case PRIVATE_KEY_CLEAR:
       break; /* no unprotection needed */
     case PRIVATE_KEY_PROTECTED:
-      rc = unprotect (ctrl, desc_text, &buf, grip, ignore_cache);
+      rc = modify_description (desc_text,
+			       comment, comment_length, &desc_text_modified);
+      if (rc)
+	log_error ("failed to modify description: %s\n", gpg_strerror (rc));
+      else
+	{
+	  rc = unprotect (ctrl, desc_text_modified, &buf, grip, ignore_cache);
+	  xfree (desc_text_modified);
 	  if (rc)
 	    log_error ("failed to unprotect the secret key: %s\n",
 		       gpg_strerror (rc));
+	}
       break;
     case PRIVATE_KEY_SHADOWED:
       if (shadow_info)