The Agent does now call the pin entry program; however because we have

not yet implemeted secret key protection, its purpose is somewhat
limited.  Well, the PIN entry modules can now be tested.

agent/Makefile.am

@@ -26,6 +26,8 @@ LDFLAGS = @LDFLAGS@
 gpg_agent_SOURCES = \
 	gpg-agent.c agent.h \
 	command.c \
+	query.c \
+	trans.c \
 	findkey.c \
 	pksign.c \
 	pkdecrypt.c

agent/agent.h

@@ -34,6 +34,8 @@ struct {
   int quiet;        /* be as quiet as possible */
   int dry_run;      /* don't change any persistent data */
   const char *homedir; /* configuration directory name */
+  const char *pinentry_program; 
+
 } opt;
 
 
@@ -66,9 +68,22 @@ struct server_control_s {
 };
 typedef struct server_control_s *CTRL;
 
+
+struct pin_entry_info_s {
+  int min_digits; /* min. number of digits required or 0 for freeform entry */
+  int max_digits; /* max. number of allowed digits allowed*/
+  int max_tries;
+  int failed_tries;
+  size_t max_length; /* allocated length of the buffer */
+  char pin[1];
+};
+
+
 /*-- gpg-agent.c --*/
 void agent_exit (int rc);
 
+/*-- trans.c --*/
+const char *trans (const char *text);
 
 /*-- command.c --*/
 void start_command_handler (void);
@@ -76,6 +91,8 @@ void start_command_handler (void);
 /*-- findkey.c --*/
 GCRY_SEXP agent_key_from_file (const unsigned char *grip);
 
+/*-- query.c --*/
+int agent_askpin (const char *desc_text, struct pin_entry_info_s *pininfo);
 
 /*-- pksign.c --*/
 int agent_pksign (CTRL ctrl, FILE *outfp);

agent/command.c

@@ -79,6 +79,11 @@ rc_to_assuan_status (int rc)
     case GNUPG_No_Secret_Key:     rc = ASSUAN_No_Secret_Key; break;
     case GNUPG_Invalid_Data:      rc = ASSUAN_Invalid_Data; break;
 
+    case GNUPG_Bad_PIN:
+    case GNUPG_Bad_Passphrase:
+      rc = ASSUAN_No_Secret_Key;
+      break;
+
     case GNUPG_Read_Error: 
     case GNUPG_Write_Error:
     case GNUPG_IO_Error: 
@@ -295,13 +300,11 @@ start_command_handler (void)
   ctrl.server_local->assuan_ctx = ctx;
   ctrl.server_local->message_fd = -1;
 
-  log_info ("Assuan started\n");
   for (;;)
     {
       rc = assuan_accept (ctx);
       if (rc == -1)
         {
-          log_info ("Assuan terminated\n");
           break;
         }
       else if (rc)

agent/findkey.c

@@ -30,6 +30,33 @@
 
 #include "agent.h"
 
+static int
+unprotect (GCRY_SEXP s_skey)
+{
+  struct pin_entry_info_s *pi;
+  int rc;
+
+  /* fixme: check whether the key needs unprotection */
+
+  /* fixme: allocate the pin in secure memory */
+  pi = xtrycalloc (1, sizeof (*pi) + 100);
+  pi->max_length = 100;
+  pi->min_digits = 4;
+  pi->max_digits = 8;
+  pi->max_tries = 3;
+
+  rc = agent_askpin (NULL, pi);
+  /* fixme: actually unprotect the key and ask again until we get a valid
+     PIN - agent_askpin takes care of counting failed tries */
+
+  xfree (pi);
+  return rc;
+}
+
+
+
+
+
 /* Return the secret key as an S-Exp after locating it using the grip.  Returns NULL if key is not available. */
 GCRY_SEXP
 agent_key_from_file (const unsigned char *grip)
@@ -86,6 +113,17 @@ agent_key_from_file (const unsigned char *grip)
       return NULL;
     }
 
+  rc = unprotect (s_skey);
+  if (rc)
+    {
+      gcry_sexp_release (s_skey);
+      log_error ("failed to unprotect the secret key: %s\n",
+                 gcry_strerror (rc));
+      return NULL;
+    }
+
   return s_skey;
 }
 
+
+

agent/gpg-agent.c

@@ -64,6 +64,9 @@ enum cmd_and_opt_values
   oFlush,
   oLogFile,
   oServer,
+  
+  oPinentryProgram,
+
 aTest };
 
 
@@ -72,7 +75,6 @@ static ARGPARSE_OPTS opts[] = {
   
   { 301, NULL, 0, N_("@Options:\n ") },
 
-  /* FIXME: add option --server */
   { oServer,   "server",     0, N_("run in server mode") },
   { oVerbose, "verbose",   0, N_("verbose") },
   { oQuiet,	"quiet",     0, N_("be somewhat more quiet") },
@@ -87,6 +89,10 @@ static ARGPARSE_OPTS opts[] = {
   { oLogFile, "log-file"   ,2, N_("use a log file for the server")},
   { oShutdown, "shutdown"  ,0, N_("shutdown the agent")},
   { oFlush   , "flush"     ,0, N_("flush the cache")},
+
+  { oPinentryProgram, "pinentry-program", 2 , "Path of PIN Entry program" },
+
+
   {0}
 };
 
@@ -384,6 +390,8 @@ main (int argc, char **argv )
         case oSh: csh_style = 0; break;
         case oServer: server_mode = 1; break;
 
+        case oPinentryProgram: opt.pinentry_program = pargs.r.ret_str; break;
+
         default : pargs.err = configfp? 1:2; break;
 	}
     }

agent/query.c

@@ -0,0 +1,219 @@
+/* query.c - fork of the pinentry to query stuff from the user
+ *	Copyright (C) 2001 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include <config.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "agent.h"
+#include "../assuan/assuan.h"
+
+#ifdef _POSIX_OPEN_MAX
+#define MAX_OPEN_FDS _POSIX_OPEN_MAX
+#else
+#define MAX_OPEN_FDS 20
+#endif
+
+#define LINELENGTH 1002 /* 1000 + [CR,]LF */
+
+static ASSUAN_CONTEXT entry_ctx = NULL;
+
+/* data to be passed to our callbacks */
+struct entry_parm_s {
+  int lines;
+  size_t size;
+  char *buffer;
+};
+
+
+
+
+/* Fork off the pin entry if this has not already been done */
+static int
+start_pinentry (void)
+{
+  int rc;
+  const char *pgmname;
+  ASSUAN_CONTEXT ctx;
+  const char *argv[3];
+
+  if (entry_ctx)
+    return 0; /* No need to serialize things becuase the agent is
+                 expected to tun as a single-thread (or may be in
+                 future using libpth) */
+
+
+  log_debug ("no running PIN Entry - starting it\n");
+      
+  if (fflush (NULL))
+    {
+      log_error ("error flushing pending output: %s\n", strerror (errno));
+      return seterr (Write_Error);
+    }
+
+  /* FIXME: change the default location of the program */
+  if (!opt.pinentry_program || !*opt.pinentry_program)
+    opt.pinentry_program = "../../pinentry/kpinentry/kpinentry";
+  if ( !(pgmname = strrchr (opt.pinentry_program, '/')))
+    pgmname = opt.pinentry_program;
+  else
+    pgmname++;
+
+  argv[0] = pgmname;
+  argv[1] = NULL;
+
+  /* connect to the pinentry and perform initial handshaking */
+  rc = assuan_pipe_connect (&ctx, opt.pinentry_program, (char**)argv);
+  if (rc)
+    {
+      log_error ("can't connect to the PIN entry module: %s\n",
+                 assuan_strerror (rc));
+      return seterr (No_PIN_Entry);
+    }
+  entry_ctx = ctx;
+  
+  log_debug ("connection to PIN entry established\n");
+
+  if (DBG_COMMAND)
+    {
+      log_debug ("waiting for debugger [hit RETURN when ready] .....\n");
+      getchar ();
+      log_debug ("... okay\n");
+    }
+
+  return 0;
+}
+
+
+static AssuanError
+getpin_cb (void *opaque, const void *buffer, size_t length)
+{
+  struct entry_parm_s *parm = opaque;
+
+  /* we expect the pin to fit on one line */
+  if (parm->lines || length >= parm->size)
+    return ASSUAN_Too_Much_Data;
+
+  /* fixme: we should make sure that the assuan buffer is allocated in
+     secure memory or read the response byte by byte */
+  memcpy (parm->buffer, buffer, length);
+  parm->buffer[length] = 0;
+  parm->lines++;
+  return 0;
+}
+
+
+static int
+all_digitsp( const char *s)
+{
+  for (; *s && *s >= '0' && *s <= '9'; s++)
+    ;
+  return !*s;
+}  
+
+
+
+/* Call the Entry and ask for the PIN.  We do chekc for a valid PIN
+   number here and repeat it as long as we have invalid formed
+   numbers. */
+int
+agent_askpin (const char *desc_text,
+              struct pin_entry_info_s *pininfo)
+{
+  int rc;
+  char line[LINELENGTH];
+  struct entry_parm_s parm;
+  const char *errtext = NULL;
+
+  if (!pininfo || pininfo->max_length < 1)
+    return seterr (Invalid_Value);
+  if (!desc_text)
+    desc_text = trans ("Please enter you PIN, so that the secret key "
+                       "can be unlocked for this session");
+  
+  rc = start_pinentry ();
+  if (rc)
+    return rc;
+
+  snprintf (line, DIM(line)-1, "SETDESC %s", desc_text);
+  line[DIM(line)-1] = 0;
+  rc = assuan_transact (entry_ctx, line, NULL, NULL, NULL, NULL);
+  if (rc)
+    return map_assuan_err (rc);
+
+  rc = assuan_transact (entry_ctx,
+                        pininfo->min_digits? "SETPROMPT PIN:"
+                                           : "SETPROMPT Passphrase:",
+                        NULL, NULL, NULL, NULL);
+  if (rc)
+    return map_assuan_err (rc);
+
+  for (;pininfo->failed_tries < pininfo->max_tries; pininfo->failed_tries++)
+    {
+      memset (&parm, 0, sizeof parm);
+      parm.size = pininfo->max_length;
+      parm.buffer = pininfo->pin;
+
+      if (errtext)
+        { 
+          /* fixme: should we show the try count? It must be translated */
+          snprintf (line, DIM(line)-1, "SETERROR %s (try %d of %d)",
+                    errtext, pininfo->failed_tries+1, pininfo->max_tries);
+          line[DIM(line)-1] = 0;
+          rc = assuan_transact (entry_ctx, line, NULL, NULL, NULL, NULL);
+          if (rc)
+            return map_assuan_err (rc);
+          errtext = NULL;
+        }
+      
+      rc = assuan_transact (entry_ctx, "GETPIN", getpin_cb, &parm, NULL, NULL);
+      if (rc == ASSUAN_Too_Much_Data)
+        errtext = pininfo->min_digits? trans ("PIN too long")
+                                     : trans ("Passphrase too long");
+      else if (rc)
+        return map_assuan_err (rc);
+      if (!errtext && !pininfo->min_digits)
+        return 0; /* okay, got a passphrase */
+      if (!errtext && !all_digitsp (pininfo->pin))
+        errtext = trans ("Invalid characters in PIN");
+      if (!errtext && pininfo->max_digits
+          && strlen (pininfo->pin) > pininfo->max_digits)
+        errtext = trans ("PIN too long");
+      if (!errtext
+          && strlen (pininfo->pin) < pininfo->min_digits)
+        errtext = trans ("PIN too short");
+
+      if (!errtext)
+        return 0; /* okay, got a PIN */
+    }
+
+  return pininfo->min_digits? GNUPG_Bad_PIN : GNUPG_Bad_Passphrase;
+}
+
+
+
+
+

agent/trans.c

@@ -0,0 +1,42 @@
+/* trans.c - translatable strings
+ *	Copyright (C) 2001 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+/* To avoid any problems with the gettext implementation (there used
+   to be some vulnerabilities in the last years and the use of
+   external files is a minor security problem in itself), we use our
+   own simple translation stuff */
+
+#include <config.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <assert.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "agent.h"
+
+const char *
+trans (const char *text)
+{
+  return text;
+}

common/errors.h

@@ -59,6 +59,10 @@ enum {
   GNUPG_Invalid_Session_Key = 30,
   GNUPG_Invalid_Sexp = 31,
   GNUPG_Unsupported_Algorithm = 32,
+  GNUPG_No_PIN_Entry = 33,
+  GNUPG_PIN_Entry_Error = 34,
+  GNUPG_Bad_PIN = 35,
+  GNUPG_Bad_Passphrase = 36,
 };
 
 /* Status codes - fixme: should go into another file */