* command-ssh.c (get_passphrase): Removed.

(ssh_identity_register): Partly rewritten.
(open_control_file, search_control_file, add_control_entry): New.
(ssh_handler_request_identities): Return only files listed in our
control file.

* findkey.c (unprotect): Check for allocation error.

* agent.h (opt): Add fields to record the startup terminal
settings.
* gpg-agent.c (main): Record them and do not force keep display
with --enable-ssh-support.
* command-ssh.c (start_command_handler_ssh): Use them here.

* gpg-agent.c: Renamed option --ssh-support to
--enable-ssh-support.

* command.c (cmd_readkey): New.
(register_commands): Register new command "READKEY".

* command-ssh.c (ssh_request_process): Improved logging.

* findkey.c (agent_write_private_key): Always use plain open.
Don't depend on an umask for permissions.
(agent_key_from_file): Factored file reading code out to ..
(read_key_file): .. new function.
(agent_public_key_from_file): New.

9 files changed, 690 insertions, 149 deletions

diff --git a/agent/ChangeLog b/agent/ChangeLog
index 420dc6368..47ca2debf 100644
--- a/agent/ChangeLog
+++ b/agent/ChangeLog
@@ -1,3 +1,33 @@
+2005-02-23  Werner Koch  <wk@g10code.com>
+
+	* command-ssh.c (get_passphrase): Removed.
+	(ssh_identity_register): Partly rewritten.
+	(open_control_file, search_control_file, add_control_entry): New.
+	(ssh_handler_request_identities): Return only files listed in our
+	control file.
+
+	* findkey.c (unprotect): Check for allocation error.
+
+	* agent.h (opt): Add fields to record the startup terminal
+	settings.
+	* gpg-agent.c (main): Record them and do not force keep display
+	with --enable-ssh-support.
+	* command-ssh.c (start_command_handler_ssh): Use them here.
+
+	* gpg-agent.c: Renamed option --ssh-support to
+	--enable-ssh-support.
+
+	* command.c (cmd_readkey): New.
+	(register_commands): Register new command "READKEY".
+
+	* command-ssh.c (ssh_request_process): Improved logging.
+
+	* findkey.c (agent_write_private_key): Always use plain open.
+	Don't depend on an umask for permissions.
+	(agent_key_from_file): Factored file reading code out to ..
+	(read_key_file): .. new function.
+	(agent_public_key_from_file): New.
+
 2005-02-22  Werner Koch  <wk@g10code.com>
 
 	* command-ssh.c (stream_read_string): Removed call to abort on
@@ -1092,21 +1122,21 @@
 
 Mon Aug 21 17:59:17 CEST 2000  Werner Koch  <wk@openit.de>
 
-        * gpg-agent.c (passphrase_dialog): Cleanup the window and added the
+	* gpg-agent.c (passphrase_dialog): Cleanup the window and added the
         user supplied text to the window.
         (main): Fixed segv in gtk_init when used without a command to start.
 
-        * gpg-agent.c: --flush option.
+	* gpg-agent.c: --flush option.
         (req_flush): New.
         (req_clear_passphrase): Implemented.
 
 Fri Aug 18 14:27:14 CEST 2000  Werner Koch  <wk@openit.de>
 
-        * gpg-agent.c: New.
-        * Makefile.am: New.
+	* gpg-agent.c: New.
+	* Makefile.am: New.
 
 
- Copyright 2001, 2002 Free Software Foundation, Inc.
+ Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
 
  This file is free software; as a special exception the author gives
  unlimited permission to copy and/or distribute it, with or without
diff --git a/agent/agent.h b/agent/agent.h
index a1196bc0b..0661cc4ad 100644
--- a/agent/agent.h
+++ b/agent/agent.h
@@ -53,6 +53,15 @@ struct {
   int dry_run;         /* Don't change any persistent data */
   int batch;           /* Batch mode */
   const char *homedir; /* Configuration directory name */
+
+  /* Environment setting gathred at program start. */
+  const char *startup_display;
+  const char *startup_ttyname;
+  const char *startup_ttytype;
+  const char *startup_lc_ctype;
+  const char *startup_lc_messages;
+
+
   const char *pinentry_program; /* Filename of the program to start as
                                    pinentry.  */
   const char *scdaemon_program; /* Filename of the program to handle
@@ -150,6 +159,9 @@ gpg_error_t agent_key_from_file (ctrl_t ctrl,
                                  const unsigned char *grip,
                                  unsigned char **shadow_info,
                                  int ignore_cache, gcry_sexp_t *result);
+gpg_error_t agent_public_key_from_file (ctrl_t ctrl, 
+                                        const unsigned char *grip,
+                                        gcry_sexp_t *result);
 int agent_key_available (const unsigned char *grip);
 
 /*-- query.c --*/
diff --git a/agent/command-ssh.c b/agent/command-ssh.c
index 1719602f2..8ea042e19 100644
--- a/agent/command-ssh.c
+++ b/agent/command-ssh.c
@@ -23,13 +23,14 @@
 
 #include <config.h>
 
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <dirent.h>
-#include <stdio.h>
+#include <assert.h>
 
 #include "agent.h"
 
@@ -63,7 +64,22 @@
 #define SSH_DSA_SIGNATURE_ELEMS    2
 #define SPEC_FLAG_USE_PKCS1V2 (1 << 0)
 
-
+
+/* The blurb we put into the header of a newly created control file.  */
+static const char sshcontrolblurb[] =
+"# List of allowed ssh keys.  Only keys present in this file are used\n"
+"# in the SSH protocol.  The ssh-add tool may add new entries to this\n"
+"# file to enable them; you may also add them manually.  Comment\n"
+"# lines, like this one, as well as empty lines are ignored.  Lines do\n"
+"# have a certain length limit but this is not serious limitation as\n" 
+"# the format of the entries is fixed and checked by gpg-agent. A\n"
+"# non-comment line starts with optional white spaces, followed by the\n"
+"# keygrip of the key given as 40 hex digits, optionally followed by a\n"
+"# the caching TTL in seconds and another optional field for arbitrary\n"
+"# flags.   Prepend the keygrip with an '!' mark to disable it.\n"
+"\n";
+
+
 
 /* Macros.  */
 
@@ -626,6 +642,155 @@ file_to_buffer (const char *filename, unsigned char **buffer, size_t *buffer_n)
 }
 
 
+
+
+/* Open the ssh control file and create it if not available. With
+   APPEND passed as true the file will be opened in append mode,
+   otherwise in read only mode.  On success a file pointer is stored
+   at the address of R_FP. */
+static gpg_error_t
+open_control_file (FILE **r_fp, int append)
+{
+  gpg_error_t err;
+  char *fname;
+  FILE *fp;
+
+  /* Note: As soon as we start to use non blocking functions here
+     (i.e. where Pth might switch threads) we need to employ a
+     mutex.  */
+  *r_fp = NULL;
+  fname = make_filename (opt.homedir, "sshcontrol.txt", NULL);
+  fp = fopen (fname, append? "a+":"r");
+  if (!fp && errno == ENOENT)
+    {
+      /* Fixme: "x" is a GNU extension.  We might want to use the es_
+         functions here.  */
+      fp = fopen (fname, "wx");  
+      if (!fp)
+        {
+          err = gpg_error (gpg_err_code_from_errno (errno));
+          log_error (_("can't create `%s': %s\n"), fname, gpg_strerror (err));
+          xfree (fname);
+          return err;
+        }
+      fputs (sshcontrolblurb, fp);
+      fclose (fp);
+      fp = fopen (fname, append? "a+":"r");
+    }
+
+  if (!fp)
+    {
+      err = gpg_error (gpg_err_code_from_errno (errno));
+      log_error (_("can't open `%s': %s\n"), fname, gpg_strerror (err));
+      xfree (fname);
+      return err;
+    }
+  
+  *r_fp = fp;  
+
+  return 0;
+}
+
+
+/* Search the file at stream FP from the beginning until a matching
+   HEXGRIP is found; return success in this case and store true at
+   DISABLED if the found key has been disabled.  */
+static gpg_error_t
+search_control_file (FILE *fp, const char *hexgrip, int *disabled)
+{
+  int c, i;
+  char *p, line[256];
+  
+  assert (strlen (hexgrip) == 40 );
+
+  rewind (fp);
+  *disabled = 0;
+ next_line:
+  do
+    {
+      if (!fgets (line, DIM(line)-1, fp) )
+        {
+          if (feof (fp))
+            return gpg_error (GPG_ERR_EOF);
+          return gpg_error (gpg_err_code_from_errno (errno));
+        }
+      
+      if (!*line || line[strlen(line)-1] != '\n')
+        {
+          /* Eat until end of line */
+          while ( (c=getc (fp)) != EOF && c != '\n')
+            ;
+          return gpg_error (*line? GPG_ERR_LINE_TOO_LONG
+                                 : GPG_ERR_INCOMPLETE_LINE);
+        }
+      
+      /* Allow for empty lines and spaces */
+      for (p=line; spacep (p); p++)
+        ;
+    }
+  while (!*p || *p == '\n' || *p == '#');
+  
+  *disabled = 0;
+  if (*p == '!')
+    {
+      *disabled = 1;
+      for (p++; spacep (p); p++)
+        ;
+    }
+
+  for (i=0; hexdigitp (p) && i < 40; p++, i++)
+    if (hexgrip[i] != (*p >= 'a'? (*p & 0xdf): *p))
+      goto next_line;
+  if (i != 40 || !(spacep (p) || *p == '\n'))
+    {
+      log_error ("invalid formatted line in ssh control file\n");
+      return gpg_error (GPG_ERR_BAD_DATA);
+    }
+
+  /* Fixme: Get TTL and flags.  */
+
+  return 0; /* Okay:  found it.  */
+}
+
+
+
+/* Add an entry to the control file to mark the key with the keygrip
+   HEXGRIP as usable for SSH; i.e. it will be returned when ssh asks
+   for it.  This function is in general used to add a key received
+   through the ssh-add function.  We can assume that the user wants to
+   allow ssh using this key. */
+static gpg_error_t
+add_control_entry (ctrl_t ctrl, const char *hexgrip, int ttl)
+{
+  gpg_error_t err;
+  FILE *fp;
+  int disabled;
+
+  err = open_control_file (&fp, 1);
+  if (err)
+    return err;
+
+  err = search_control_file (fp, hexgrip, &disabled);
+  if (err && gpg_err_code(err) == GPG_ERR_EOF)
+    {
+      struct tm *tp;
+      time_t atime = time (NULL);
+
+      /* Not yet in the file - add it. Becuase the file has been
+         opened in append mode, we simply need to write to it.  */
+      tp = localtime (&atime);
+      fprintf (fp, "# Key added on %04d-%02d-%02d %02d:%02d:%02d\n%s %d\n",
+               1900+tp->tm_year, tp->tm_mon+1, tp->tm_mday,
+               tp->tm_hour, tp->tm_min, tp->tm_sec,
+               hexgrip, ttl);
+               
+    }
+  fclose (fp);
+  return 0;
+}
+
+
+
 
 
 /*
@@ -1377,6 +1542,7 @@ ssh_handler_request_identities (ctrl_t ctrl,
   gpg_error_t err;
   gpg_error_t ret_err;
   int ret;
+  FILE *ctrl_fp = NULL;
 
   /* Prepare buffer stream.  */
 
@@ -1427,6 +1593,19 @@ ssh_handler_request_identities (ctrl_t ctrl,
 
   /* FIXME: make sure that buffer gets deallocated properly.  */
 
+  /* Fixme: We should better iterate over the control file and check
+     whether the key file is there.  This is better in resepct to
+     performance if tehre are a lot of key sin our key storage. */
+
+  err = open_control_file (&ctrl_fp, 0);
+  if (err)
+    goto out;
+
+#warning Really need to fix this fixme.
+  /*
+ FIXME:  First check whether a key is currently available in the card reader - this should be allowed even without being listed in sshcontrol.txt.
+  */
+
   while (1)
     {
       dir_entry = readdir (dir);
@@ -1435,6 +1614,19 @@ ssh_handler_request_identities (ctrl_t ctrl,
 	  if ((strlen (dir_entry->d_name) == 44)
 	      && (! strncmp (dir_entry->d_name + 40, ".key", 4)))
 	    {
+              char hexgrip[41];
+              int disabled;
+
+              /* We do only want to return keys listed in our control
+                 file. */
+              strncpy (hexgrip, dir_entry->d_name, 40);
+              hexgrip[40] = 0;
+              if ( strlen (hexgrip) != 40 )
+                continue;
+              if (search_control_file (ctrl_fp, hexgrip, &disabled)
+                  || disabled)
+                continue;
+
 	      strncpy (key_path + key_directory_n + 1, dir_entry->d_name, 40);
 
 	      /* Read file content.  */
@@ -1522,6 +1714,9 @@ ssh_handler_request_identities (ctrl_t ctrl,
   if (dir)
     closedir (dir);
 
+  if (ctrl_fp)
+    fclose (ctrl_fp);
+
   free (key_directory);
   xfree (key_path);
   xfree (buffer);
@@ -1802,43 +1997,6 @@ ssh_handler_sign_request (ctrl_t ctrl, estream_t request, estream_t response)
   return ret_err;
 }
 
-static gpg_error_t
-get_passphrase (ctrl_t ctrl,
-		const char *description, size_t passphrase_n, char *passphrase)
-{
-  struct pin_entry_info_s *pi;
-  gpg_error_t err;
-
-  err = 0;
-  pi = gcry_calloc_secure (1, sizeof (*pi) + passphrase_n + 1);
-  if (! pi)
-    {
-      err = gpg_error (GPG_ERR_ENOMEM);
-      goto out;
-    }
-
-  pi->min_digits = 0;		/* We want a real passphrase.  */
-  pi->max_digits = 8;
-  pi->max_tries = 1;
-  pi->failed_tries = 0;
-  pi->check_cb = NULL;
-  pi->check_cb_arg = NULL;
-  pi->cb_errtext = NULL;
-  pi->max_length = 100;
-
-  err = agent_askpin (ctrl, description, NULL, pi);
-  if (err)
-    goto out;
-
-  memcpy (passphrase, pi->pin, passphrase_n);
-  passphrase[passphrase_n] = 0;
-
- out:
-
-  xfree (pi);
-  
-  return err;
-}
 
 static gpg_error_t
 ssh_key_extract_comment (gcry_sexp_t key, char **comment)
@@ -1929,76 +2087,100 @@ ssh_key_to_buffer (gcry_sexp_t key, const char *passphrase,
   return err;
 }
 
+
+
+/* Store the ssh KEY into our local key storage and protect him after
+   asking for a passphrase.  Cache that passphrase.  TTL is the
+   maximum caching time for that key.  If the key already exists in
+   our key storage, don't do anything.  When entering a new key also
+   add an entry to the sshcontrol file.  */
 static gpg_error_t
 ssh_identity_register (ctrl_t ctrl, gcry_sexp_t key, int ttl)
 {
+  gpg_error_t err;
   unsigned char key_grip_raw[21];
-  unsigned char *buffer;
-  unsigned int buffer_n;
-  char passphrase[100];
-  char *description;
   char key_grip[41];
-  char *comment;
-  gpg_error_t err;
+  unsigned char *buffer = NULL;
+  unsigned int buffer_n;
+  char *description = NULL;
+  char *comment = NULL;
   unsigned int i;
-  int ret;
-
-  description = NULL;
-  comment = NULL;
-  buffer = NULL;
+  struct pin_entry_info_s *pi = NULL;
 
   err = ssh_key_grip (key, key_grip_raw);
   if (err)
     goto out;
 
-  key_grip_raw[sizeof (key_grip_raw) - 1] = 0;
-  ret = agent_key_available (key_grip_raw);
-  if (! ret)
-    goto out;
+  key_grip_raw[sizeof (key_grip_raw) - 1] = 0; /* FIXME:  Why?? */
 
+  /* Check whether the key is alread in our key storage.  Don't do
+     anything then.  */
+  if ( !agent_key_available (key_grip_raw) )
+    goto out; /* Yes, key is available.  */
+
+  
   err = ssh_key_extract_comment (key, &comment);
   if (err)
     goto out;
 
-  ret = asprintf (&description,
-		  "Please provide the passphrase, which should be used "
-		  "for protecting the received secret key `%s':",
-		  comment ? comment : "");
-  if (ret < 0)
+  if ( asprintf (&description,
+                 _("Please enter a passphrase to protect%%0A"
+                   "the received secret key%%0A"
+                   "   %s%%0A"
+                   "within gpg-agent's key storage"),
+                 comment ? comment : "?") < 0)
     {
-      err = gpg_err_code_from_errno (errno);
+      err = gpg_error_from_errno (errno);
       goto out;
     }
 
-  err = get_passphrase (ctrl, description, sizeof (passphrase), passphrase);
+
+  pi = gcry_calloc_secure (1, sizeof (*pi) + 100 + 1);
+  if (!pi)
+    {
+      err = gpg_error_from_errno (errno);
+      goto out;
+    }
+  pi->max_length = 100;
+  pi->max_tries = 1;
+  err = agent_askpin (ctrl, description, NULL, pi);
   if (err)
     goto out;
 
-  err = ssh_key_to_buffer (key, passphrase, &buffer, &buffer_n);
+  err = ssh_key_to_buffer (key, pi->pin, &buffer, &buffer_n);
   if (err)
     goto out;
 
+  /* Store this key to our key storage.  */
   err = agent_write_private_key (key_grip_raw, buffer, buffer_n, 0);
   if (err)
     goto out;
 
+  /* Cache this passphrase. */
   for (i = 0; i < 20; i++)
     sprintf (key_grip + 2 * i, "%02X", key_grip_raw[i]);
 
-  err = agent_put_cache (key_grip, passphrase, ttl);
+  err = agent_put_cache (key_grip, pi->pin, ttl);
   if (err)
     goto out;
 
- out:
+  /* And add an entry to the sshcontrol file.  */
+  err = add_control_entry (ctrl, key_grip, ttl);
 
+
+ out:
+  if (pi && pi->max_length)
+    wipememory (pi->pin, pi->max_length);
+  xfree (pi);
   xfree (buffer);
   xfree (comment);
-  free (description);
-  /* FIXME: verify xfree vs free.  */
+  free (description); /* (asprintf allocated, thus regular free.)  */
 
   return err;
 }
 
+
+
 static gpg_error_t
 ssh_identity_drop (gcry_sexp_t key)
 {
@@ -2234,12 +2416,9 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
   if (err)
     goto out;
 
-  if (opt.verbose) /* FIXME: using log_debug is not good with
-                      verbose. log_debug should only be used in
-                      debugging mode or in sitattions which are
-                      unexpected. */
-    log_debug ("received request of length: %u\n",
-	       request_data_size);
+  if (opt.verbose > 1)
+    log_info ("received ssh request of length %u\n",
+              (unsigned int)request_data_size);
 
   request = es_mopen (NULL, 0, 0, 1, realloc_secure, gcry_free, "r+");
   if (! request)
@@ -2277,17 +2456,28 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
       break;
   if (i == DIM (request_specs))
     {
-      log_debug ("request %u is not supported\n",
-		 request_type);
+      log_info ("ssh request %u is not supported\n", request_type);
       send_err = 1;
       goto out;
     }
 
   if (opt.verbose)
-    log_debug ("executing request handler: %s (%u)\n",
+    log_info ("ssh request handler for %s (%u) started\n",
 	       request_specs[i].identifier, request_specs[i].type);
 
   err = (*request_specs[i].handler) (ctrl, request, response);
+
+  if (opt.verbose)
+    {
+      if (err)
+        log_info ("ssh request handler for %s (%u) failed: %s\n",
+                  request_specs[i].identifier, request_specs[i].type,
+                  gpg_strerror (err));
+      else
+        log_info ("ssh request handler for %s (%u) ready\n",
+                  request_specs[i].identifier, request_specs[i].type);
+    }
+
   if (err)
     {
       send_err = 1;
@@ -2295,6 +2485,10 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
     }
 
   response_size = es_ftell (response);
+  if (opt.verbose > 1)
+    log_info ("sending ssh response of length %u\n",
+              (unsigned int)response_size);
+
   err = es_fseek (response, 0, SEEK_SET);
   if (err)
     {
@@ -2325,6 +2519,8 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
 
   if (send_err)
     {
+      if (opt.verbose > 1)
+        log_info ("sending ssh error response\n");
       err = stream_write_uint32 (stream_sock, 1);
       if (err)
 	goto leave;
@@ -2341,7 +2537,7 @@ ssh_request_process (ctrl_t ctrl, estream_t stream_sock)
     es_fclose (response);
   xfree (request_data);		/* FIXME?  */
 
-  return !! err;
+  return !!err;
 }
 
 void
@@ -2359,6 +2555,21 @@ start_command_handler_ssh (int sock_client)
   agent_init_default_ctrl (&ctrl);
   ctrl.connection_fd = sock_client;
 
+  /* Because the ssh protocol does not send us information about the
+     the current TTY setting, we resort here to use those from startup
+     or those explictly set.  */
+  if (!ctrl.display && opt.startup_display)
+    ctrl.display = strdup (opt.startup_display);
+  if (!ctrl.ttyname && opt.startup_ttyname)
+    ctrl.ttyname = strdup (opt.startup_ttyname);
+  if (!ctrl.ttytype && opt.startup_ttytype)
+    ctrl.ttytype = strdup (opt.startup_ttytype);
+  if (!ctrl.lc_ctype && opt.startup_lc_ctype)
+    ctrl.lc_ctype = strdup (opt.startup_lc_ctype);
+  if (!ctrl.lc_messages && opt.startup_lc_messages)
+    ctrl.lc_messages = strdup (opt.startup_lc_messages);
+
+
   /* Create stream from socket.  */
   stream_sock = es_fdopen (sock_client, "r+");
   if (!stream_sock)
diff --git a/agent/command.c b/agent/command.c
index dc8a4a158..997140207 100644
--- a/agent/command.c
+++ b/agent/command.c
@@ -1,5 +1,5 @@
 /* command.c - gpg-agent command handler
- * Copyright (C) 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+ * Copyright (C) 2001, 2002, 2003, 2004, 2005  Free Software Foundation, Inc.
  *
  * This file is part of GnuPG.
  *
@@ -22,12 +22,14 @@
    some buffering in secure mempory to protect session keys etc. */
 
 #include <config.h>
+
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <ctype.h>
 #include <unistd.h>
+#include <assert.h>
 
 #include <assuan.h>
 
@@ -504,6 +506,55 @@ cmd_genkey (ASSUAN_CONTEXT ctx, char *line)
 }
 
 
+
+
+/* READKEY <hexstring_with_keygrip>
+  
+   Return the public key for the given keygrip.  */
+static int
+cmd_readkey (assuan_context_t ctx, char *line)
+{
+  ctrl_t ctrl = assuan_get_pointer (ctx);
+  int rc;
+  unsigned char grip[20];
+  gcry_sexp_t s_pkey = NULL;
+
+  rc = parse_keygrip (ctx, line, grip);
+  if (rc)
+    return rc; /* Return immediately as this is already an Assuan error code.*/
+
+  rc = agent_public_key_from_file (ctrl, grip, &s_pkey);
+  if (!rc)
+    {
+      size_t len;
+      unsigned char *buf;
+
+      len = gcry_sexp_sprint (s_pkey, GCRYSEXP_FMT_CANON, NULL, 0);
+      assert (len);
+      buf = xtrymalloc (len);
+      if (!buf)
+        rc = gpg_error_from_errno (errno);
+      else
+        {
+          len = gcry_sexp_sprint (s_pkey, GCRYSEXP_FMT_CANON, buf, len);
+          assert (len);
+          rc = assuan_send_data (ctx, buf, len);
+          rc = map_assuan_err (rc);
+          xfree (buf);
+        }
+      gcry_sexp_release (s_pkey);
+    }
+
+  if (rc)
+    log_error ("command readkey failed: %s\n", gpg_strerror (rc));
+  return map_to_assuan_status (rc);
+}
+
+
+
+
+
+
 /* GET_PASSPHRASE <cache_id> [<error_message> <prompt> <description>]
 
    This function is usually used to ask for a passphrase to be used
@@ -894,6 +945,7 @@ register_commands (ASSUAN_CONTEXT ctx)
     { "PKSIGN",         cmd_pksign },
     { "PKDECRYPT",      cmd_pkdecrypt },
     { "GENKEY",         cmd_genkey },
+    { "READKEY",        cmd_readkey },
     { "GET_PASSPHRASE", cmd_get_passphrase },
     { "PRESET_PASSPHRASE", cmd_preset_passphrase },
     { "CLEAR_PASSPHRASE", cmd_clear_passphrase },
diff --git a/agent/findkey.c b/agent/findkey.c
index 1ac57ad07..86a28d511 100644
--- a/agent/findkey.c
+++ b/agent/findkey.c
@@ -39,7 +39,9 @@ struct try_unprotect_arg_s {
 };
 
 
-
+/* Write an S-expression formatted key to our key storage.  With FORCE
+   pased as true an existsing key with the given GRIP will get
+   overwritten.  */
 int
 agent_write_private_key (const unsigned char *grip,
                          const void *buffer, size_t length, int force)
@@ -48,51 +50,44 @@ agent_write_private_key (const unsigned char *grip,
   char *fname;
   FILE *fp;
   char hexgrip[40+4+1];
+  int fd;
   
   for (i=0; i < 20; i++)
     sprintf (hexgrip+2*i, "%02X", grip[i]);
   strcpy (hexgrip+40, ".key");
 
   fname = make_filename (opt.homedir, GNUPG_PRIVATE_KEYS_DIR, hexgrip, NULL);
-  if (force)
-    fp = fopen (fname, "wb");
-  else
-    {
-      int fd;
-
-      if (!access (fname, F_OK))
-      {
-        log_error ("secret key file `%s' already exists\n", fname);
-        xfree (fname);
-        return gpg_error (GPG_ERR_GENERAL);
-      }
 
-      /* We would like to create FNAME but only if it does not already
-	 exist.  We cannot make this guarantee just using POSIX (GNU
-	 provides the "x" opentype for fopen, however, this is not
-	 portable).  Thus, we use the more flexible open function and
-	 then use fdopen to obtain a stream.
+  if (!force && !access (fname, F_OK))
+    {
+      log_error ("secret key file `%s' already exists\n", fname);
+      xfree (fname);
+      return gpg_error (GPG_ERR_GENERAL);
+    }
 
-	 The mode parameter to open is what fopen uses.  It will be
-	 combined with the process' umask automatically.  */
-      fd = open (fname, O_CREAT | O_EXCL | O_RDWR,
-		 S_IRUSR | S_IWUSR 
+  /* In FORCE mode we would like to create FNAME but only if it does
+     not already exist.  We cannot make this guarantee just using
+     POSIX (GNU provides the "x" opentype for fopen, however, this is
+     not portable).  Thus, we use the more flexible open function and
+     then use fdopen to obtain a stream. */
+  fd = open (fname, force? (O_CREAT | O_TRUNC | O_WRONLY)
+                         : (O_CREAT | O_EXCL | O_WRONLY),
+             S_IRUSR | S_IWUSR 
 #ifndef HAVE_W32_SYSTEM
-                 | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH
+                 | S_IRGRP 
 #endif
                  );
-      if (fd < 0)
-	fp = 0;
-      else
-	{
-	  fp = fdopen (fd, "wb");
-	  if (!fp)
-            { 
-              int save_e = errno;
-              close (fd);
-              errno = save_e;
-            }
-	}
+  if (fd < 0)
+    fp = NULL;
+  else
+    {
+      fp = fdopen (fd, "wb");
+      if (!fp)
+        { 
+          int save_e = errno;
+          close (fd);
+          errno = save_e;
+        }
     }
 
   if (!fp) 
@@ -263,6 +258,8 @@ unprotect (CTRL ctrl, const char *desc_text,
     }
   
   pi = gcry_calloc_secure (1, sizeof (*pi) + 100);
+  if (!pi)
+    return gpg_error_from_errno (errno);
   pi->max_length = 100;
   pi->min_digits = 0;  /* we want a real passphrase */
   pi->max_digits = 8;
@@ -285,32 +282,22 @@ unprotect (CTRL ctrl, const char *desc_text,
 }
 
 
-
-/* Return the secret key as an S-Exp in RESULT after locating it using
-   the grip.  Returns NULL in RESULT if the operation should be
-   diverted to a token; SHADOW_INFO will point then to an allocated
-   S-Expression with the shadow_info part from the file.  With
-   IGNORE_CACHE passed as true the passphrase is not taken from the
-   cache.  DESC_TEXT may be set to present a custom description for the
-   pinentry. */
-gpg_error_t
-agent_key_from_file (CTRL ctrl, const char *desc_text,
-                     const unsigned char *grip, unsigned char **shadow_info,
-                     int ignore_cache, gcry_sexp_t *result)
+/* Read the key identified by GRIP from the private key directory and
+   return it as an gcrypt S-expression object in RESULT.  On failure
+   returns an error code and stores NULL at RESULT. */
+static gpg_error_t
+read_key_file (const unsigned char *grip, gcry_sexp_t *result)
 {
   int i, rc;
   char *fname;
   FILE *fp;
   struct stat st;
   unsigned char *buf;
-  size_t len, buflen, erroff;
+  size_t buflen, erroff;
   gcry_sexp_t s_skey;
   char hexgrip[40+4+1];
-  int got_shadow_info = 0;
   
   *result = NULL;
-  if (shadow_info)
-      *shadow_info = NULL;
 
   for (i=0; i < 20; i++)
     sprintf (hexgrip+2*i, "%02X", grip[i]);
@@ -336,8 +323,8 @@ agent_key_from_file (CTRL ctrl, const char *desc_text,
     }
 
   buflen = st.st_size;
-  buf = xmalloc (buflen+1);
-  if (fread (buf, buflen, 1, fp) != 1)
+  buf = xtrymalloc (buflen+1);
+  if (!buf || fread (buf, buflen, 1, fp) != 1)
     {
       rc = gpg_error_from_errno (errno);
       log_error ("error reading `%s': %s\n", fname, strerror (errno));
@@ -347,6 +334,7 @@ agent_key_from_file (CTRL ctrl, const char *desc_text,
       return rc;
     }
 
+  /* Convert the file into a gcrypt S-expression object.  */
   rc = gcry_sexp_sscan (&s_skey, &erroff, buf, buflen);
   xfree (fname);
   fclose (fp);
@@ -357,18 +345,52 @@ agent_key_from_file (CTRL ctrl, const char *desc_text,
                  (unsigned int)erroff, gpg_strerror (rc));
       return rc;
     }
+  *result = s_skey;
+  return 0;
+}
+
+
+/* Return the secret key as an S-Exp in RESULT after locating it using
+   the grip.  Returns NULL in RESULT if the operation should be
+   diverted to a token; SHADOW_INFO will point then to an allocated
+   S-Expression with the shadow_info part from the file.  With
+   IGNORE_CACHE passed as true the passphrase is not taken from the
+   cache.  DESC_TEXT may be set to present a custom description for the
+   pinentry. */
+gpg_error_t
+agent_key_from_file (ctrl_t ctrl, const char *desc_text,
+                     const unsigned char *grip, unsigned char **shadow_info,
+                     int ignore_cache, gcry_sexp_t *result)
+{
+  int rc;
+  unsigned char *buf;
+  size_t len, buflen, erroff;
+  gcry_sexp_t s_skey;
+  int got_shadow_info = 0;
+  
+  *result = NULL;
+  if (shadow_info)
+      *shadow_info = NULL;
+
+  rc = read_key_file (grip, &s_skey);
+  if (rc)
+    return rc;
+
+  /* For use with the protection functions we also need the key as an
+     canonical encoded S-expression in abuffer.  Create this buffer
+     now.  */
   len = gcry_sexp_sprint (s_skey, GCRYSEXP_FMT_CANON, NULL, 0);
   assert (len);
   buf = xtrymalloc (len);
   if (!buf)
     {
-      rc = out_of_core ();
+      rc = gpg_error_from_errno (errno);
       gcry_sexp_release (s_skey);
       return rc;
     }
   len = gcry_sexp_sprint (s_skey, GCRYSEXP_FMT_CANON, buf, len);
   assert (len);
-  gcry_sexp_release (s_skey);
+
 
   switch (agent_private_key_type (buf))
     {
@@ -381,7 +403,7 @@ agent_key_from_file (CTRL ctrl, const char *desc_text,
 	char *desc_text_final;
 	const char *comment = NULL;
 
-        /* Note, that we will take the comment as a C styring for
+        /* Note, that we will take the comment as a C string for
            display purposes; i.e. all stuff beyond a Nul character is
            ignored.  */
 	comment_sexp = gcry_sexp_find_token (s_skey, "comment", 0);
@@ -460,6 +482,8 @@ agent_key_from_file (CTRL ctrl, const char *desc_text,
       rc = gpg_error (GPG_ERR_BAD_SECKEY);
       break;
     }
+  gcry_sexp_release (s_skey);
+  s_skey = NULL;
   if (rc || got_shadow_info)
     {
       xfree (buf);
@@ -481,6 +505,200 @@ agent_key_from_file (CTRL ctrl, const char *desc_text,
   return 0;
 }
 
+
+
+/* Return the public key for the keygrip GRIP.  The result is stored
+   at RESULT.  This function extracts the public key from the private
+   key database.  On failure an error code is returned and NULL stored
+   at RESULT. */
+gpg_error_t
+agent_public_key_from_file (ctrl_t ctrl, 
+                            const unsigned char *grip,
+                            gcry_sexp_t *result)
+{
+  int i, idx, rc;
+  gcry_sexp_t s_skey;
+  const char *algoname;
+  gcry_sexp_t uri_sexp, comment_sexp;
+  const char *uri, *comment;
+  size_t uri_length, comment_length;
+  char *format, *p;
+  void *args[4+2+2+1]; /* Size is max. # of elements + 2 for uri + 2
+                           for comment + end-of-list.  */
+  int argidx;
+  gcry_sexp_t list, l2;
+  const char *name;
+  const char *s;
+  size_t n;
+  const char *elems;
+  gcry_mpi_t *array;
+
+  *result = NULL;
+
+  rc = read_key_file (grip, &s_skey);
+  if (rc)
+    return rc;
+
+  list = gcry_sexp_find_token (s_skey, "shadowed-private-key", 0 );
+  if (!list)
+    list = gcry_sexp_find_token (s_skey, "protected-private-key", 0 );
+  if (!list)
+    list = gcry_sexp_find_token (s_skey, "private-key", 0 );
+  if (!list)
+    {
+      log_error ("invalid private key format\n");
+      gcry_sexp_release (s_skey);
+      return gpg_error (GPG_ERR_BAD_SECKEY);
+    }
+
+  l2 = gcry_sexp_cadr (list);
+  gcry_sexp_release (list);
+  list = l2;
+  name = gcry_sexp_nth_data (list, 0, &n);
+  if (n==3 && !memcmp (name, "rsa", 3))
+    {
+      algoname = "rsa";
+      elems = "ne";
+    }
+  else if (n==3 && !memcmp (name, "dsa", 3))
+    {
+      algoname = "dsa";
+      elems = "pqgy";
+    }
+  else if (n==3 && !memcmp (name, "elg", 3))
+    {
+      algoname = "elg";
+      elems = "pgy";
+    }
+  else
+    {
+      log_error ("unknown private key algorithm\n");
+      gcry_sexp_release (list);
+      gcry_sexp_release (s_skey);
+      return gpg_error (GPG_ERR_BAD_SECKEY);
+    }
+
+  /* Allocate an array for the parameters and copy them out of the
+     secret key.   FIXME: We should have a generic copy function. */
+  array = xtrycalloc (strlen(elems) + 1, sizeof *array);
+  if (!array)
+    {
+      rc = gpg_error_from_errno (errno);
+      gcry_sexp_release (list);
+      gcry_sexp_release (s_skey);
+      return rc;
+    }
+
+  for (idx=0, s=elems; *s; s++, idx++ ) 
+    {
+      l2 = gcry_sexp_find_token (list, s, 1);
+      if (!l2)
+        {
+          /* Required parameter not found.  */
+          for (i=0; i<idx; i++)
+            gcry_mpi_release (array[i]);
+          xfree (array);
+          gcry_sexp_release (list);
+          gcry_sexp_release (s_skey);
+          return gpg_error (GPG_ERR_BAD_SECKEY);
+	}
+      array[idx] = gcry_sexp_nth_mpi (l2, 1, GCRYMPI_FMT_USG);
+      gcry_sexp_release (l2);
+      if (!array[idx])
+        {
+          /* Required parameter is invalid. */
+          for (i=0; i<idx; i++)
+            gcry_mpi_release (array[i]);
+          xfree (array);
+          gcry_sexp_release (list);
+          gcry_sexp_release (s_skey);
+          return gpg_error (GPG_ERR_BAD_SECKEY);
+	}
+    }
+  gcry_sexp_release (list);
+  list = NULL;
+
+  uri = NULL;
+  uri_length = 0;
+  uri_sexp = gcry_sexp_find_token (s_skey, "uri", 0);
+  if (uri_sexp)
+    uri = gcry_sexp_nth_data (uri_sexp, 1, &uri_length);
+
+  comment = NULL;
+  comment_length = 0;
+  comment_sexp = gcry_sexp_find_token (s_skey, "comment", 0);
+  if (comment_sexp)
+    comment = gcry_sexp_nth_data (comment_sexp, 1, &comment_length);
+
+  gcry_sexp_release (s_skey);
+  s_skey = NULL;
+
+
+  /* FIXME: The following thing is pretty ugly code; we should
+     investigate how to make it cleaner. Probably code to handle
+     canonical S-expressions in a memory buffer is better suioted for
+     such a task.  After all that is what we do in protect.c.  Neeed
+     to find common patterns and write a straightformward API to use
+     them.  */
+  assert (sizeof (size_t) <= sizeof (void*));
+
+  format = xtrymalloc (15+7*strlen (elems)+10+15+1+1);
+  if (!format)
+    {
+      rc = gpg_error_from_errno (errno);
+      for (i=0; array[i]; i++)
+        gcry_mpi_release (array[i]);
+      xfree (array);
+      gcry_sexp_release (uri_sexp);
+      gcry_sexp_release (comment_sexp);
+      return rc;
+    }
+
+  argidx = 0;
+  p = stpcpy (stpcpy (format, "(public-key("), algoname);
+  for (idx=0, s=elems; *s; s++, idx++ ) 
+    {
+      *p++ = '(';
+      *p++ = *s;
+      p = stpcpy (p, " %m)");
+      assert (argidx < DIM (args));
+      args[argidx++] = array[idx];
+    }
+  *p++ = ')';
+  if (uri)
+    {
+      p = stpcpy (p, "(uri %b)");
+      assert (argidx+1 < DIM (args));
+      args[argidx++] = (void *)uri_length;
+      args[argidx++] = (void *)uri;
+    }
+  if (comment)
+    {
+      p = stpcpy (p, "(comment %b)");
+      assert (argidx+1 < DIM (args));
+      args[argidx++] = (void *)comment_length;
+      args[argidx++] = (void*)comment;
+    }
+  *p++ = ')';
+  *p = 0;
+  assert (argidx < DIM (args));
+  args[argidx] = NULL;
+    
+  rc = gcry_sexp_build_array (&list, NULL, format, args);
+  xfree (format);
+  for (i=0; array[i]; i++)
+    gcry_mpi_release (array[i]);
+  xfree (array);
+  gcry_sexp_release (uri_sexp);
+  gcry_sexp_release (comment_sexp);
+
+  if (!rc)
+    *result = list;
+  return rc;
+}
+
+
+
 /* Return the secret key as an S-Exp after locating it using the grip.
    Returns NULL if key is not available. 0 = key is available */
 int
diff --git a/agent/gpg-agent.c b/agent/gpg-agent.c
index 47488ee69..338248d1a 100644
--- a/agent/gpg-agent.c
+++ b/agent/gpg-agent.c
@@ -1,5 +1,5 @@
 /* gpg-agent.c  -  The GnuPG Agent
- *	Copyright (C) 2000, 2001, 2002, 2003,
+ *	Copyright (C) 2000, 2001, 2002, 2003, 2004,
  *                    2005 Free Software Foundation, Inc.
  *
  * This file is part of GnuPG.
@@ -147,7 +147,7 @@ static ARGPARSE_OPTS opts[] = {
                              N_("allow clients to mark keys as \"trusted\"")},
   { oAllowPresetPassphrase, "allow-preset-passphrase", 0,
                              N_("allow presetting passphrase")},
-  { oSSHSupport, "ssh-support", 0, N_("enable secure ssh-agent emulation") },
+  { oSSHSupport, "enable-ssh-support", 0, N_("enable ssh-agent emulation") },
   {0}
 };
 
@@ -458,7 +458,6 @@ main (int argc, char **argv )
   int standard_socket = 0;
   gpg_error_t err;
 
-
   set_strusage (my_strusage);
   gcry_control (GCRYCTL_SUSPEND_SECMEM_WARN);
   /* Please note that we may running SUID(ROOT), so be very CAREFUL
@@ -513,6 +512,23 @@ main (int argc, char **argv )
 
   opt.homedir = default_homedir ();
 
+  /* Record the some original Denvironment settings. */
+  opt.startup_display = getenv ("DISPLAY");
+  if (opt.startup_display)
+    opt.startup_display = xstrdup (opt.startup_display);
+  opt.startup_ttyname = ttyname (0);
+  if (opt.startup_ttyname)
+    opt.startup_ttyname = xstrdup (opt.startup_ttyname);
+  opt.startup_ttytype = getenv ("TERM");
+  if (opt.startup_ttytype)
+    opt.startup_ttytype = xstrdup (opt.startup_ttytype);
+  /* Fixme: Neen to use the locale fucntion here.  */
+  opt.startup_lc_ctype = getenv ("LC_CTYPE");
+  if (opt.startup_lc_ctype) 
+    opt.startup_lc_ctype = xstrdup (opt.startup_lc_ctype);
+  opt.startup_lc_messages = getenv ("LC_MESSAGES");
+  if (opt.startup_lc_messages)
+    opt.startup_lc_messages = xstrdup (opt.startup_lc_messages);
 
   /* Check whether we have a config file on the commandline */
   orig_argc = argc;
@@ -624,11 +640,7 @@ main (int argc, char **argv )
         case oKeepTTY: opt.keep_tty = 1; break;
         case oKeepDISPLAY: opt.keep_display = 1; break;
 
-	case oSSHSupport:
-	  opt.ssh_support = 1;
-	  opt.keep_tty  = 1;
-	  opt.keep_display = 1;
-	  break;
+	case oSSHSupport:  opt.ssh_support = 1; break;
 
         default : pargs.err = configfp? 1:2; break;
 	}
@@ -784,7 +796,7 @@ main (int argc, char **argv )
 
       /* Remove the DISPLAY variable so that a pinentry does not
          default to a specific display.  There is still a default
-         display when gpg-agent weas started using --display or a
+         display when gpg-agent was started using --display or a
          client requested this using an OPTION command. */
 #ifndef HAVE_W32_SYSTEM
       if (!opt.keep_display)
diff --git a/agent/keyformat.txt b/agent/keyformat.txt
index 6c0bd8b83..726990315 100644
--- a/agent/keyformat.txt
+++ b/agent/keyformat.txt
@@ -31,8 +31,12 @@ Libgcrypt.  Here is an example of an unprotected file:
   (u #304559a..[some bytes not shown]..9b#)
  )
  (uri http://foo.bar x-foo:whatever_you_want)
+ (comment whatever)
 )
 
+"comment" and "uri" are optional.  "comment" is currently used to keep
+track of ssh key comments.
+
 Actually this form should not be used for regular purposes and only
 accepted by gpg-agent with the configuration option:
 --allow-non-canonical-key-format.  The regular way to represent the
@@ -62,6 +66,7 @@ A protected key is like this:
     (protected mode (parms) encrypted_octet_string)
    )
    (uri http://foo.bar x-foo:whatever_you_want)
+   (comment whatever)
 )  
 
 
@@ -134,6 +139,7 @@ to keys stored on a token:
     (shadowed protocol (info))
    )
    (uri http://foo.bar x-foo:whatever_you_want)
+   (comment whatever)
 )  
 
 The currently used protocol is "ti-v1" (token info version 1).  The
diff --git a/agent/protect.c b/agent/protect.c
index edcca36d9..cafeb4685 100644
--- a/agent/protect.c
+++ b/agent/protect.c
@@ -117,7 +117,7 @@ calculate_mic (const unsigned char *plainkey, unsigned char *sha1hash)
 
 /* Encrypt the parameter block starting at PROTBEGIN with length
    PROTLEN using the utf8 encoded key PASSPHRASE and return the entire
-   encrypted block in RESULT or ereturn with an error code.  SHA1HASH
+   encrypted block in RESULT or return with an error code.  SHA1HASH
    is the 20 byte SHA-1 hash required for the integrity code.
 
    The parameter block is expected to be an incomplete S-Expression of
diff --git a/agent/query.c b/agent/query.c
index 4aafcbe99..622a2662c 100644
--- a/agent/query.c
+++ b/agent/query.c
@@ -86,7 +86,7 @@ initialize_module_query (void)
 /* Unlock the pinentry so that another thread can start one and
    disconnect that pinentry - we do this after the unlock so that a
    stalled pinentry does not block other threads.  Fixme: We should
-   have a timeout in Assuan for the disconnetc operation. */
+   have a timeout in Assuan for the disconnect operation. */
 static int 
 unlock_pinentry (int rc)
 {