summaryrefslogtreecommitdiffstats
path: root/imap/auth_sasl.c
blob: 1cf997d4eedc37389c6c0661eb845533cfc800cf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
/*
 * Copyright (C) 2000-2006,2012 Brendan Cully <brendan@kublai.com>
 * 
 *     This program 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.
 * 
 *     This program 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */ 

/* SASL login/authentication code */

#if HAVE_CONFIG_H
# include "config.h"
#endif

#include "mutt.h"
#include "mutt_sasl.h"
#include "imap_private.h"
#include "auth.h"

#include <sasl/sasl.h>
#include <sasl/saslutil.h>

/* imap_auth_sasl: Default authenticator if available. */
imap_auth_res_t imap_auth_sasl (IMAP_DATA* idata, const char* method)
{
  sasl_conn_t* saslconn;
  sasl_interact_t* interaction = NULL;
  int rc, irc;
  char *buf = NULL;
  size_t bufsize = 0;
  const char* mech;
  const char *pc = NULL;
  unsigned int len, olen;
  unsigned char client_start;

  if (mutt_sasl_client_new (idata->conn, &saslconn) < 0)
  {
    dprint (1, (debugfile,
      "imap_auth_sasl: Error allocating SASL connection.\n"));
    return IMAP_AUTH_FAILURE;
  }

  rc = SASL_FAIL;

  /* If the user hasn't specified a method, use any available */
  if (!method)
  {
    method = idata->capstr;

    /* hack for SASL ANONYMOUS support:
     * 1. Fetch username. If it's "" or "anonymous" then
     * 2. attempt sasl_client_start with only "AUTH=ANONYMOUS" capability
     * 3. if sasl_client_start fails, fall through... */

    if (mutt_account_getuser (&idata->conn->account))
      return IMAP_AUTH_FAILURE;

    if (mutt_bit_isset (idata->capabilities, AUTH_ANON) &&
	(!idata->conn->account.user[0] ||
	 !ascii_strncmp (idata->conn->account.user, "anonymous", 9)))
      rc = sasl_client_start (saslconn, "AUTH=ANONYMOUS", NULL, &pc, &olen, 
                              &mech);
  } else if (!ascii_strcasecmp ("login", method) &&
	!strstr (NONULL (idata->capstr), "AUTH=LOGIN"))
    /* do not use SASL login for regular IMAP login (#3556) */
    return IMAP_AUTH_UNAVAIL;
  
  if (rc != SASL_OK && rc != SASL_CONTINUE)
    do
    {
      rc = sasl_client_start (saslconn, method, &interaction,
        &pc, &olen, &mech);
      if (rc == SASL_INTERACT)
	mutt_sasl_interact (interaction);
    }
    while (rc == SASL_INTERACT);

  client_start = (olen > 0);

  if (rc != SASL_OK && rc != SASL_CONTINUE)
  {
    if (method)
      dprint (2, (debugfile, "imap_auth_sasl: %s unavailable\n", method));
    else
      dprint (1, (debugfile, "imap_auth_sasl: Failure starting authentication exchange. No shared mechanisms?\n"));
    /* SASL doesn't support LOGIN, so fall back */

    return IMAP_AUTH_UNAVAIL;
  }

  mutt_message (_("Authenticating (%s)..."), mech);

  bufsize = ((olen * 2) > LONG_STRING) ? (olen * 2) : LONG_STRING;
  buf = safe_malloc (bufsize);

  snprintf (buf, bufsize, "AUTHENTICATE %s", mech);
  if (mutt_bit_isset (idata->capabilities, SASL_IR) && client_start)
  {
    len = mutt_strlen (buf);
    buf[len++] = ' ';
    if (sasl_encode64 (pc, olen, buf + len, bufsize - len, &olen) != SASL_OK)
    {
      dprint (1, (debugfile, "imap_auth_sasl: error base64-encoding client response.\n"));
      goto bail;
    }
    client_start = olen = 0;
  }
  imap_cmd_start (idata, buf);
  irc = IMAP_CMD_CONTINUE;

  /* looping protocol */
  while (rc == SASL_CONTINUE || olen > 0)
  {
    do
      irc = imap_cmd_step (idata);
    while (irc == IMAP_CMD_CONTINUE);

    if (irc == IMAP_CMD_BAD || irc == IMAP_CMD_NO)
      goto bail;

    if (irc == IMAP_CMD_RESPOND)
    {
      /* Exchange incorrectly returns +\r\n instead of + \r\n */
      if (idata->buf[1] == '\0')
      {
	buf[0] = '\0';
	len = 0;
      }
      else
      {
        len = strlen (idata->buf + 2);
        if (len > bufsize)
        {
          bufsize = len;
          safe_realloc (&buf, bufsize);
        }
        /* For sasl_decode64, the fourth parameter, outmax, doesn't
         * include space for the trailing null */
        if (sasl_decode64 (idata->buf+2, len, buf, bufsize - 1, &len) != SASL_OK)
        {
          dprint (1, (debugfile, "imap_auth_sasl: error base64-decoding server response.\n"));
          goto bail;
        }
      }
    }

    /* client-start is only available with the SASL-IR extension, but
     * SASL 2.1 seems to want to use it regardless, at least for DIGEST
     * fast reauth. Override if the server sent an initial continuation */
    if (!client_start || buf[0])
    {
      do
      {
	rc = sasl_client_step (saslconn, buf, len, &interaction, &pc, &olen);
	if (rc == SASL_INTERACT)
	  mutt_sasl_interact (interaction);
      }
      while (rc == SASL_INTERACT);
    }
    else
      client_start = 0;

    /* send out response, or line break if none needed */
    if (olen)
    {
      if ((olen * 2) > bufsize)
      {
        bufsize = olen * 2;
        safe_realloc (&buf, bufsize);
      }
      if (sasl_encode64 (pc, olen, buf, bufsize, &olen) != SASL_OK)
      {
	dprint (1, (debugfile, "imap_auth_sasl: error base64-encoding client response.\n"));
	goto bail;
      }
    }
    
    if (irc == IMAP_CMD_RESPOND)
    {
      strfcpy (buf + olen, "\r\n", bufsize - olen);
      mutt_socket_write (idata->conn, buf);
    }

    /* If SASL has errored out, send an abort string to the server */
    if (rc < 0)
    {
      mutt_socket_write (idata->conn, "*\r\n");
      dprint (1, (debugfile, "imap_auth_sasl: sasl_client_step error %d\n",rc));
    }
	  
    olen = 0;
  }

  while (irc != IMAP_CMD_OK)
    if ((irc = imap_cmd_step (idata)) != IMAP_CMD_CONTINUE)
      break;

  if (rc != SASL_OK)
    goto bail;

  if (imap_code (idata->buf))
  {
    mutt_sasl_setup_conn (idata->conn, saslconn);
    FREE (&buf);
    return IMAP_AUTH_SUCCESS;
  }

 bail:
  sasl_dispose (&saslconn);
  FREE (&buf);

  if (method)
  {
    dprint (2, (debugfile, "imap_auth_sasl: %s failed\n", method));
    return IMAP_AUTH_UNAVAIL;
  }

  mutt_error _("SASL authentication failed.");
  mutt_sleep(2);

  return IMAP_AUTH_FAILURE;
}