Added to the repository

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2003 Free Software Foundation, Inc.
+
+   GNU Mailutils 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, or (at your option)
+   any later version.
+
+   GNU Mailutils 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 GNU Mailutils; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA  */
+
+#include "imap4d.h"
+#include <gsasl.h>
+#include <mailutils/gsasl.h>
+
+static Gsasl_ctx *ctx;   
+static Gsasl_session_ctx *sess_ctx; 
+
+static int
+create_gsasl_stream (stream_t *newstr, stream_t str, int flags)
+{
+  int rc;
+  
+  rc = gsasl_stream_create (newstr, str, sess_ctx, flags);
+  if (rc)
+    {
+      syslog (LOG_ERR, _("cannot create SASL stream: %s"),
+	      mu_errstring (rc));
+      return RESP_NO;
+    }
+
+  if ((rc = stream_open (*newstr)) != 0)
+    {
+      char *p;
+      if (stream_strerror (*newstr, &p))
+	p = mu_errstring (rc);
+      syslog (LOG_ERR, _("cannot open SASL input stream: %s"), p);
+      return RESP_NO;
+    }
+
+  return RESP_OK;
+}
+
+
+static int
+auth_gsasl (struct imap4d_command *command,
+	     char *auth_type, char *arg, char **username)
+{
+  char *input = NULL;
+  char output[512];
+  size_t output_len;
+  char *s, *client_init;
+  int rc;
+
+  client_init = util_getword (arg, &s);
+  if (!client_init)
+    return RESP_BAD;
+  util_unquote (&client_init);
+  
+  rc = gsasl_server_start (ctx, auth_type, &sess_ctx);
+  if (rc != GSASL_OK)
+    {
+      syslog (LOG_NOTICE, _("SASL gsasl_server_start: %s"),
+	      gsasl_strerror(rc));
+      return 0;
+    }
+
+  gsasl_server_application_data_set (sess_ctx, username);
+
+  input = client_init;
+  output[0] = '\0';
+  output_len = sizeof (output);
+
+  while ((rc = gsasl_server_step_base64 (sess_ctx, input, output, output_len))
+	 == GSASL_NEEDS_MORE)
+    {
+      util_send ("+ %s\r\n", output);
+      input = imap4d_readline_ex ();
+    }
+  while (rc == GSASL_NEEDS_MORE);
+
+  if (rc != GSASL_OK)
+    {
+      syslog (LOG_NOTICE, _("GSASL error: %s"), gsasl_strerror (rc));
+      return RESP_NO;
+    }
+
+  if (*username == NULL)
+    {
+      syslog (LOG_NOTICE, _("GSASL %s: cannot get username"), auth_type);
+      return RESP_NO;
+    }
+
+  if (sess_ctx)
+    {
+      stream_t in, out, new_in, new_out;
+      
+      util_get_input (&in);
+      util_get_output (&out);
+      if (create_gsasl_stream (&new_in, in, MU_STREAM_READ))
+	return RESP_NO;
+      if (create_gsasl_stream (&new_out, out, MU_STREAM_WRITE))
+	{
+	  stream_destroy (&new_in, stream_get_owner (new_in));
+	  return RESP_NO;
+	}
+
+      util_set_input (new_in);
+      util_set_output (new_out);
+    }
+
+  auth_gsasl_capa_init (1);
+  return RESP_OK;
+}
+
+static void
+auth_gsasl_capa_init (int disable)
+{
+  int rc;
+  char *listmech, *name, *s;
+  size_t size;
+
+  rc = gsasl_server_listmech (ctx, NULL, &size);
+  if (rc != GSASL_OK)
+    return;
+
+  listmech = malloc (size);
+  if (!listmech)
+    imap4d_bye (ERR_NO_MEM);
+  
+  rc = gsasl_server_listmech (ctx, listmech, &size);
+  if (rc != GSASL_OK)
+    return;
+
+  for (name = strtok_r (listmech, " ", &s); name;
+       name = strtok_r (NULL, " ", &s))
+    {
+      if (disable)
+	auth_remove (name);
+      else
+	auth_add (strdup (name), auth_gsasl);
+    }
+      
+  free (listmech);
+}
+
+/* This is for DIGEST-MD5 */
+static int
+cb_realm (Gsasl_session_ctx *ctx, char *out, size_t *outlen, size_t nth)
+{
+  char *realm = util_localname ();
+
+  if (nth > 0)
+    return GSASL_NO_MORE_REALMS;
+
+  if (out)
+    {
+      if (*outlen < strlen (realm))
+	return GSASL_TOO_SMALL_BUFFER;
+      memcpy (out, realm, strlen (realm));
+    }
+
+  *outlen = strlen (realm);
+
+  return GSASL_OK;
+}
+
+static int
+cb_validate (Gsasl_session_ctx *ctx,
+	     const char *authorization_id,
+	     const char *authentication_id,
+	     const char *password)
+{
+  char **username = gsasl_server_application_data_get (ctx);
+  *username = strdup (authentication_id ?
+		      authentication_id : authorization_id);
+  return GSASL_OK;
+}
+
+#define GSSAPI_SERVICE "imap"
+
+static int
+cb_service (Gsasl_session_ctx *ctx, char *srv, size_t *srvlen,
+	    char *host, size_t *hostlen)
+{
+  char *hostname = util_localname ();
+
+  if (srv)
+    {
+      if (*srvlen < strlen (GSSAPI_SERVICE))
+       return GSASL_TOO_SMALL_BUFFER;
+
+      memcpy (srv, GSSAPI_SERVICE, strlen (GSSAPI_SERVICE));
+    }
+
+  if (srvlen)
+    *srvlen = strlen (GSSAPI_SERVICE);
+
+  if (host)
+    {
+      if (*hostlen < strlen (hostname))
+       return GSASL_TOO_SMALL_BUFFER;
+
+      memcpy (host, hostname, strlen (hostname));
+    }
+
+  if (hostlen)
+    *hostlen = strlen (hostname);
+
+  return GSASL_OK;
+}
+
+/* This gets called when SASL mechanism EXTERNAL is invoked */
+static int
+cb_external (Gsasl_session_ctx *ctx)
+{
+  return GSASL_AUTHENTICATION_ERROR;
+}
+
+void
+auth_gsasl_init ()
+{
+  int rc;
+  
+  rc = gsasl_init (&ctx);
+  if (rc != GSASL_OK)
+    {
+      syslog (LOG_NOTICE, _("cannot initialize libgsasl: %s"),
+	      gsasl_strerror (rc));
+    }
+
+  gsasl_server_callback_realm_set (ctx, cb_realm);
+  gsasl_server_callback_external_set (ctx, cb_external);
+  gsasl_server_callback_validate_set (ctx, cb_validate);
+  gsasl_server_callback_service_set (ctx, cb_service);
+
+  auth_gsasl_capa_init (0);
+}
+