gnupg/sm/call-dirmngr.c

/* call-dirmngr.c - communication with the dromngr 
 *	Copyright (C) 2002 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h> 
#include <time.h>
#include <assert.h>

#include <gcrypt.h>

#include "gpgsm.h"
#include "../assuan/assuan.h"
#include "i18n.h"

struct membuf {
  size_t len;
  size_t size;
  char *buf;
  int out_of_core;
};



static ASSUAN_CONTEXT dirmngr_ctx = NULL;
static int force_pipe_server = 0;

struct inq_certificate_parm_s {
  ASSUAN_CONTEXT ctx;
  KsbaCert cert;
};

struct lookup_parm_s {
  CTRL ctrl;
  ASSUAN_CONTEXT ctx;
  void (*cb)(void *, KsbaCert);
  void *cb_value;
  struct membuf data;
  int error;
};




/* A simple implementation of a dynamic buffer.  Use init_membuf() to
   create a buffer, put_membuf to append bytes and get_membuf to
   release and return the buffer.  Allocation errors are detected but
   only returned at the final get_membuf(), this helps not to clutter
   the code with out of core checks.  */

static void
init_membuf (struct membuf *mb, int initiallen)
{
  mb->len = 0;
  mb->size = initiallen;
  mb->out_of_core = 0;
  mb->buf = xtrymalloc (initiallen);
  if (!mb->buf)
      mb->out_of_core = 1;
}

static void
put_membuf (struct membuf *mb, const void *buf, size_t len)
{
  if (mb->out_of_core)
    return;

  if (mb->len + len >= mb->size)
    {
      char *p;
      
      mb->size += len + 1024;
      p = xtryrealloc (mb->buf, mb->size);
      if (!p)
        {
          mb->out_of_core = 1;
          return;
        }
      mb->buf = p;
    }
  memcpy (mb->buf + mb->len, buf, len);
  mb->len += len;
}

static void *
get_membuf (struct membuf *mb, size_t *len)
{
  char *p;

  if (mb->out_of_core)
    {
      xfree (mb->buf);
      mb->buf = NULL;
      return NULL;
    }

  p = mb->buf;
  *len = mb->len;
  mb->buf = NULL;
  mb->out_of_core = 1; /* don't allow a reuse */
  return p;
}





/* Try to connect to the agent via socket or fork it off and work by
   pipes.  Handle the server's initial greeting */
static int
start_dirmngr (void)
{
  int rc;
  char *infostr, *p;
  ASSUAN_CONTEXT ctx;

  if (dirmngr_ctx)
    return 0; /* fixme: We need a context for each thread or serialize
                 the access to the dirmngr */

  infostr = force_pipe_server? NULL : getenv ("DIRMNGR_INFO");
  if (!infostr)
    {
      const char *pgmname;
      const char *argv[3];
      int no_close_list[3];
      int i;

      if (opt.verbose)
        log_info (_("no running dirmngr - starting one\n"));
      
      if (fflush (NULL))
        {
          log_error ("error flushing pending output: %s\n", strerror (errno));
          return seterr (Write_Error);
        }

      if (!opt.dirmngr_program || !*opt.dirmngr_program)
        opt.dirmngr_program = "/usr/sbin/dirmngr";
      if ( !(pgmname = strrchr (opt.dirmngr_program, '/')))
        pgmname = opt.dirmngr_program;
      else
        pgmname++;

      argv[0] = pgmname;
      argv[1] = "--server";
      argv[2] = NULL;

      i=0;
      if (log_get_fd () != -1)
        no_close_list[i++] = log_get_fd ();
      no_close_list[i++] = fileno (stderr);
      no_close_list[i] = -1;

      /* connect to the agent and perform initial handshaking */
      rc = assuan_pipe_connect (&ctx, opt.dirmngr_program, (char**)argv,
                                no_close_list);
    }
  else
    {
      int prot;
      int pid;

      infostr = xstrdup (infostr);
      if ( !(p = strchr (infostr, ':')) || p == infostr)
        {
          log_error (_("malformed DIRMNGR_INFO environment variable\n"));
          xfree (infostr);
          force_pipe_server = 1;
          return start_dirmngr ();
        }
      *p++ = 0;
      pid = atoi (p);
      while (*p && *p != ':')
        p++;
      prot = *p? atoi (p+1) : 0;
      if (prot != 1)
        {
          log_error (_("dirmngr protocol version %d is not supported\n"),
                     prot);
          xfree (infostr);
          force_pipe_server = 1;
          return start_dirmngr ();
        }

      rc = assuan_socket_connect (&ctx, infostr, pid);
      xfree (infostr);
      if (rc == ASSUAN_Connect_Failed)
        {
          log_error (_("can't connect to the dirmngr - trying fall back\n"));
          force_pipe_server = 1;
          return start_dirmngr ();
        }
    }

  if (rc)
    {
      log_error ("can't connect to the dirmngr: %s\n", assuan_strerror (rc));
      return seterr (No_Dirmngr);
    }
  dirmngr_ctx = ctx;

  if (DBG_ASSUAN)
    log_debug ("connection to dirmngr established\n");
  return 0;
}



/* Handle a SENDCERT inquiry. */
static AssuanError
inq_certificate (void *opaque, const char *line)
{
  struct inq_certificate_parm_s *parm = opaque;
  AssuanError rc;
  const unsigned char *der;
  size_t derlen;

  if (!(!strncmp (line, "SENDCERT", 8) && (line[8] == ' ' || !line[8])))
    {
      log_error ("unsupported inquiry `%s'\n", line);
      return ASSUAN_Inquire_Unknown;
    }
  line += 8;

  if (!*line)
    { /* send the current certificate */
      der = ksba_cert_get_image (parm->cert, &derlen);
      if (!der)
        rc = ASSUAN_Inquire_Error;
      else
        rc = assuan_send_data (parm->ctx, der, derlen);
    }
  else 
    { /* send the given certificate */
      int err;
      KsbaCert cert;

      err = gpgsm_find_cert (line, &cert);
      if (err)
        {
          log_error ("certificate not found: %s\n", gnupg_strerror (err));
          rc = ASSUAN_Inquire_Error;
        }
      else
        {
          der = ksba_cert_get_image (cert, &derlen);
          if (!der)
            rc = ASSUAN_Inquire_Error;
          else
            rc = assuan_send_data (parm->ctx, der, derlen);
          ksba_cert_release (cert);
        }
    }

  return rc; 
}



/* Call the directory manager to check whether the certificate is valid
   Returns 0 for valid or usually one of the errors:

  GNUPG_Certificate_Revoked
  GNUPG_No_CRL_Known
  GNUPG_CRL_Too_Old
 */
int
gpgsm_dirmngr_isvalid (KsbaCert cert)
{
  int rc;
  char *certid;
  char line[ASSUAN_LINELENGTH];
  struct inq_certificate_parm_s parm;

  rc = start_dirmngr ();
  if (rc)
    return rc;

  certid = gpgsm_get_certid (cert);
  if (!certid)
    {
      log_error ("error getting the certificate ID\n");
      return seterr (General_Error);
    }

  parm.ctx = dirmngr_ctx;
  parm.cert = cert;

  snprintf (line, DIM(line)-1, "ISVALID %s", certid);
  line[DIM(line)-1] = 0;
  xfree (certid);

  rc = assuan_transact (dirmngr_ctx, line, NULL, NULL,
                        inq_certificate, &parm, NULL, NULL);
  return map_assuan_err (rc);
}



/* Lookup helpers*/
static AssuanError
lookup_cb (void *opaque, const void *buffer, size_t length)
{
  struct lookup_parm_s *parm = opaque;
  size_t len;
  char *buf;
  KsbaCert cert;
  int rc;

  if (parm->error)
    return 0;

  if (buffer)
    {
      put_membuf (&parm->data, buffer, length);
      return 0;
    }
  /* END encountered - process what we have */
  buf = get_membuf (&parm->data, &len);
  if (!buf)
    {
      parm->error = GNUPG_Out_Of_Core;
      return 0;
    }

  cert = ksba_cert_new ();
  if (!cert)
    {
      parm->error = GNUPG_Out_Of_Core;
      return 0;
    }
  rc = ksba_cert_init_from_mem (cert, buf, len);
  if (rc)
    {
      log_error ("failed to parse a certificate: %s\n", ksba_strerror (rc));
    }
  else
    {
      parm->cb (parm->cb_value, cert);
    }

  ksba_cert_release (cert);
  init_membuf (&parm->data, 4096);
  return 0;
}

/* Return a properly escaped pattern from NAMES.  The only error
   return is NULL to indicate a malloc failure. */
static char *
pattern_from_strlist (STRLIST names)
{
  STRLIST sl;
  int n;
  const char *s;
  char *pattern, *p;

  for (n=0, sl=names; sl; sl = sl->next)
    {
      for (s=sl->d; *s; s++, n++)
	{
          if (*s == '%' || *s == ' ' || *s == '+')
            n += 2;
	}
      n++;
    }

  p = pattern = xtrymalloc (n+1);
  if (!pattern)
    return NULL;

  for (n=0, sl=names; sl; sl = sl->next)
    {
      for (s=sl->d; *s; s++)
        {
          switch (*s)
            {
            case '%':
              *p++ = '%';
              *p++ = '2';
              *p++ = '5';
              break;
            case ' ':
              *p++ = '%';
              *p++ = '2';
              *p++ = '0';
              break;
            case '+':
              *p++ = '%';
              *p++ = '2';
              *p++ = 'B';
              break;
            default:
              *p++ = *s;
              break;
            }
        }
      *p++ = ' ';
    }
  if (p == pattern)
    *pattern = 0; /* is empty */
  else
    p[-1] = '\0'; /* remove trailing blank */
  
  return pattern;
}

static AssuanError
lookup_status_cb (void *opaque, const char *line)
{
  struct lookup_parm_s *parm = opaque;

  if (!strncmp (line, "TRUNCATED", 9) && (line[9]==' ' || !line[9]))
    {
      for (line +=9; *line == ' '; line++)
        ;
      gpgsm_status (parm->ctrl, STATUS_TRUNCATED, line);
    }
  return 0;
}


/* Run the Directroy Managers lookup command using the apptern
   compiled from the strings given in NAMES.  The caller must provide
   the callback CB which will be passed cert by cert. */
int 
gpgsm_dirmngr_lookup (CTRL ctrl, STRLIST names,
                      void (*cb)(void*, KsbaCert), void *cb_value)
{ 
  int rc;
  char *pattern;
  char line[ASSUAN_LINELENGTH];
  struct lookup_parm_s parm;
  size_t len;

  rc = start_dirmngr ();
  if (rc)
    return rc;

  pattern = pattern_from_strlist (names);
  if (!pattern)
    return GNUPG_Out_Of_Core;
  snprintf (line, DIM(line)-1, "LOOKUP %s", pattern);
  line[DIM(line)-1] = 0;
  xfree (pattern);

  parm.ctrl = ctrl;
  parm.ctx = dirmngr_ctx;
  parm.cb = cb;
  parm.cb_value = cb_value;
  parm.error = 0;
  init_membuf (&parm.data, 4096);

  rc = assuan_transact (dirmngr_ctx, line, lookup_cb, &parm,
                        NULL, NULL, lookup_status_cb, &parm);
  xfree (get_membuf (&parm.data, &len));
  if (rc)
    return map_assuan_err (rc);
  return parm.error;
}