summaryrefslogtreecommitdiff
path: root/src/providers/ldap/sdap_access.c
blob: 4a30b74be723921bea2e9afddc74767fd9f30d5d (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
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
/*
    SSSD

    sdap_access.c

    Authors:
        Stephen Gallagher <sgallagh@redhat.com>

    Copyright (C) 2010 Red Hat

    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 3 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, see <http://www.gnu.org/licenses/>.
*/

#include <sys/param.h>
#include <security/pam_modules.h>
#include <talloc.h>
#include <tevent.h>
#include <errno.h>

#include "util/util.h"
#include "db/sysdb.h"
#include "providers/ldap/ldap_common.h"
#include "providers/ldap/sdap.h"
#include "providers/ldap/sdap_access.h"
#include "providers/ldap/sdap_async.h"
#include "providers/data_provider.h"
#include "providers/dp_backend.h"

static void sdap_access_reply(struct be_req *be_req, int pam_status)
{
    struct pam_data *pd;
    pd = talloc_get_type(be_req->req_data, struct pam_data);
    pd->pam_status = pam_status;

    if (pam_status == PAM_SUCCESS || pam_status == PAM_PERM_DENIED) {
        be_req->fn(be_req, DP_ERR_OK, pam_status, NULL);
    }

    else {
        be_req->fn(be_req, DP_ERR_FATAL, pam_status, NULL);
    }
}

static struct tevent_req *sdap_access_send(TALLOC_CTX *mem_ctx,
                                           struct tevent_context *ev,
                                           struct be_ctx *be_ctx,
                                           struct sdap_access_ctx *access_ctx,
                                           const char *username);
static void sdap_access_done(struct tevent_req *req);
void sdap_pam_access_handler(struct be_req *breq)
{
    struct pam_data *pd;
    struct tevent_req *req;
    struct sdap_access_ctx *access_ctx;

    pd = talloc_get_type(breq->req_data, struct pam_data);

    access_ctx =
            talloc_get_type(breq->be_ctx->bet_info[BET_ACCESS].pvt_bet_data,
                            struct sdap_access_ctx);

    req = sdap_access_send(breq,
                           breq->be_ctx->ev,
                           breq->be_ctx,
                           access_ctx,
                           pd->user);
    if (req == NULL) {
        DEBUG(1, ("Unable to start sdap_access request\n"));
        sdap_access_reply(breq, PAM_SYSTEM_ERR);
        return;
    }

    tevent_req_set_callback(req, sdap_access_done, breq);
}

struct sdap_access_req_ctx {
    const char *username;
    const char *filter;
    struct tevent_context *ev;
    struct sdap_access_ctx *access_ctx;
    struct sdap_id_ctx *sdap_ctx;
    struct sdap_id_op *sdap_op;
    struct sysdb_handle *handle;
    struct be_ctx *be_ctx;
    const char **attrs;
    int pam_status;
    bool cached_access;
    char *basedn;
};

static void sdap_access_decide_offline(struct tevent_req *req);
static int sdap_access_retry(struct tevent_req *req);
static void sdap_access_connect_done(struct tevent_req *subreq);
static void sdap_access_get_access_done(struct tevent_req *req);
static struct tevent_req *sdap_access_send(TALLOC_CTX *mem_ctx,
                                           struct tevent_context *ev,
                                           struct be_ctx *be_ctx,
                                           struct sdap_access_ctx *access_ctx,
                                           const char *username)
{
    errno_t ret;
    struct sdap_access_req_ctx *state;
    struct tevent_req *req;
    struct ldb_result *res;
    const char *basedn;

    req = tevent_req_create(mem_ctx, &state, struct sdap_access_req_ctx);
    if (req == NULL) {
        return NULL;
    }

    if (access_ctx->filter == NULL || *access_ctx->filter == '\0') {
        /* If no filter is set, default to restrictive */
        DEBUG(6, ("No filter set. Access is denied.\n"));
        state->pam_status = PAM_PERM_DENIED;
        tevent_req_done(req);
        tevent_req_post(req, be_ctx->ev);
        return req;
    }

    state->filter = NULL;
    state->be_ctx = be_ctx;
    state->username = username;
    state->pam_status = PAM_SYSTEM_ERR;
    state->sdap_ctx = access_ctx->id_ctx;
    state->ev = ev;
    state->access_ctx = access_ctx;

    state->attrs = talloc_array(state, const char *, 3);
    if (state->attrs == NULL) {
        DEBUG(1, ("Could not allocate attributes\n"));
        goto failed;
    }

    state->attrs[0] = SYSDB_ORIG_DN;
    state->attrs[1] = SYSDB_LDAP_ACCESS;
    state->attrs[2] = NULL;

    DEBUG(6, ("Performing access check for user [%s]\n", username));

    /* Get original user DN */
    ret = sysdb_get_user_attr(state, be_ctx->sysdb,
                              be_ctx->domain, username,
                              state->attrs,
                              &res);
    if (ret != EOK) {
        if (ret == ENOENT) {
            /* If we can't find the user, return permission denied */
            state->pam_status = PAM_PERM_DENIED;
            goto finished;
        }
        goto failed;
    }
    else {
        if (res->count == 0) {
            /* If we can't find the user, return permission denied */
            state->pam_status = PAM_PERM_DENIED;
            goto finished;
        }

        if (res->count != 1) {
            DEBUG(1, ("Invalid response from sysdb_get_user_attr\n"));
            goto failed;
        }
    }

    /* Exactly one result returned */
    state->cached_access = ldb_msg_find_attr_as_bool(res->msgs[0],
                                                     SYSDB_LDAP_ACCESS,
                                                     false);
    /* Ok, we have one result, check if we are online or offline */
    if (be_is_offline(state->be_ctx)) {
        /* Ok, we're offline. Return from the cache */
        sdap_access_decide_offline(req);
        goto finished;
    }

    /* Perform online operation */
    basedn = ldb_msg_find_attr_as_string(res->msgs[0],
                                         SYSDB_ORIG_DN,
                                         NULL);
    if(basedn == NULL) {
        DEBUG(1,("Could not find originalDN for user [%s]\n",
                 state->username));
        goto failed;
    }

    state->basedn = talloc_strdup(state, basedn);
    if (state->basedn == NULL) {
        DEBUG(1, ("Could not allocate memory for originalDN\n"));
        goto failed;
    }
    talloc_zfree(res);

    /* Construct the filter */
    state->filter = talloc_asprintf(
        state,
        "(&(%s=%s)(objectclass=%s)%s)",
        state->sdap_ctx->opts->user_map[SDAP_AT_USER_NAME].name,
        state->username,
        state->sdap_ctx->opts->user_map[SDAP_OC_USER].name,
        state->access_ctx->filter);
    if (state->filter == NULL) {
        DEBUG(0, ("Could not construct access filter\n"));
        goto failed;
    }

    DEBUG(6, ("Checking filter against LDAP\n"));

    state->sdap_op = sdap_id_op_create(state, state->sdap_ctx->conn_cache);
    if (!state->sdap_op) {
        DEBUG(2, ("sdap_id_op_create failed\n"));
        goto failed;
    }

    ret = sdap_access_retry(req);
    if (ret != EOK) {
        goto failed;
    }

    return req;

failed:
    talloc_free(req);
    return NULL;

finished:
    tevent_req_done(req);
    tevent_req_post(req, ev);
    return req;
}

static void sdap_access_decide_offline(struct tevent_req *req)
{
    struct sdap_access_req_ctx *state =
            tevent_req_data(req, struct sdap_access_req_ctx);

    if (state->cached_access) {
        DEBUG(6, ("Access granted by cached credentials\n"));
        state->pam_status = PAM_SUCCESS;
    } else {
        DEBUG(6, ("Access denied by cached credentials\n"));
        state->pam_status = PAM_PERM_DENIED;
    }
}

static int sdap_access_retry(struct tevent_req *req)
{
    struct sdap_access_req_ctx *state =
            tevent_req_data(req, struct sdap_access_req_ctx);
    struct tevent_req *subreq;
    int ret;

    subreq = sdap_id_op_connect_send(state->sdap_op, state, &ret);
    if (!subreq) {
        DEBUG(2, ("sdap_id_op_connect_send failed: %d (%s)\n", ret, strerror(ret)));
        return ret;
    }

    tevent_req_set_callback(subreq, sdap_access_connect_done, req);
    return EOK;
}

static void sdap_access_connect_done(struct tevent_req *subreq)
{
    struct tevent_req *req = tevent_req_callback_data(subreq,
                                                      struct tevent_req);
    struct sdap_access_req_ctx *state =
            tevent_req_data(req, struct sdap_access_req_ctx);
    int ret, dp_error;

    ret = sdap_id_op_connect_recv(subreq, &dp_error);
    talloc_zfree(subreq);

    if (ret != EOK) {
        if (dp_error == DP_ERR_OFFLINE) {
            sdap_access_decide_offline(req);
            tevent_req_done(req);
            return;
        }

        tevent_req_error(req, ret);
        return;
    }

    /* Connection to LDAP succeeded
     * Send filter request
     */
    subreq = sdap_get_generic_send(state,
                                   state->ev,
                                   state->sdap_ctx->opts,
                                   sdap_id_op_handle(state->sdap_op),
                                   state->basedn,
                                   LDAP_SCOPE_BASE,
                                   state->filter, NULL,
                                   NULL, 0);
    if (subreq == NULL) {
        DEBUG(1, ("Could not start LDAP communication\n"));
        state->pam_status = PAM_SYSTEM_ERR;
        tevent_req_error(req, EIO);
        return;
    }

    tevent_req_set_callback(subreq, sdap_access_get_access_done, req);
}

static void sdap_access_get_access_done(struct tevent_req *subreq)
{
    int ret, dp_error;
    size_t num_results;
    bool found = false;
    struct sysdb_attrs *attrs;
    struct sysdb_attrs **results;
    struct tevent_req *req =
            tevent_req_callback_data(subreq, struct tevent_req);
    struct sdap_access_req_ctx *state =
            tevent_req_data(req, struct sdap_access_req_ctx);
    ret = sdap_get_generic_recv(subreq, state,
                                &num_results, &results);
    talloc_zfree(subreq);

    ret = sdap_id_op_done(state->sdap_op, ret, &dp_error);
    if (ret != EOK) {
        if (dp_error == DP_ERR_OK) {
            /* retry */
            ret = sdap_access_retry(req);
            if (ret == EOK) {
                return;
            }
            state->pam_status = PAM_SYSTEM_ERR;
        } else if (dp_error == DP_ERR_OFFLINE) {
            sdap_access_decide_offline(req);
        } else {
            DEBUG(1, ("sdap_get_generic_send() returned error [%d][%s]\n",
                      ret, strerror(ret)));
            state->pam_status = PAM_SYSTEM_ERR;
        }

        goto done;
    }

    /* Check the number of responses we got
     * If it's exactly 1, we passed the check
     * If it's < 1, we failed the check
     * Anything else is an error
     */
    if (num_results < 1) {
        DEBUG(4, ("User [%s] was not found with the specified filter. "
                  "Denying access.\n", state->username));
        found = false;
    }
    else if (results == NULL) {
        DEBUG(1, ("num_results > 0, but results is NULL\n"));
        ret = EIO;
        state->pam_status = PAM_SYSTEM_ERR;
        goto done;
    }
    else if (num_results > 1) {
        /* It should not be possible to get more than one reply
         * here, since we're doing a base-scoped search
         */
        DEBUG(1, ("Received multiple replies\n"));
        ret = EIO;
        state->pam_status = PAM_SYSTEM_ERR;
        goto done;
    }
    else { /* Ok, we got a single reply */
        found = true;
    }

    if (found) {
        /* Save "allow" to the cache for future offline
         * access checks.
         */
        DEBUG(6, ("Access granted by online lookup\n"));
        state->pam_status = PAM_SUCCESS;
    }
    else {
        /* Save "disallow" to the cache for future offline
         * access checks.
         */
        DEBUG(6, ("Access denied by online lookup\n"));
        state->pam_status = PAM_PERM_DENIED;
    }

    attrs = sysdb_new_attrs(state);
    if (attrs == NULL) {
        ret = ENOMEM;
        DEBUG(1, ("Could not set up attrs\n"));
        goto done;
    }

    ret = sysdb_attrs_add_bool(attrs, SYSDB_LDAP_ACCESS,
                               state->pam_status == PAM_SUCCESS ?
                                                    true :
                                                    false);
    if (ret != EOK) {
        /* Failing to save to the cache is non-fatal.
         * Just return the result.
         */
        ret = EOK;
        DEBUG(1, ("Could not set up attrs\n"));
        goto done;
    }

    ret = sysdb_set_user_attr(attrs,
                              state->be_ctx->sysdb,
                              state->be_ctx->domain,
                              state->username,
                              attrs, SYSDB_MOD_REP);
    if (ret != EOK) {
        /* Failing to save to the cache is non-fatal.
         * Just return the result.
         */
        ret = EOK;
        DEBUG(1, ("Failed to set user access attribute\n"));
        goto done;
    }

done:
    if (ret == EOK) {
        tevent_req_done(req);
    }
    else {
        tevent_req_error(req, ret);
    }
}

static errno_t sdap_access_recv(struct tevent_req *req, int *pam_status)
{
    struct sdap_access_req_ctx *state =
            tevent_req_data(req, struct sdap_access_req_ctx);

    TEVENT_REQ_RETURN_ON_ERROR(req);

    *pam_status = state->pam_status;

    return EOK;
}

static void sdap_access_done(struct tevent_req *req)
{
    errno_t ret;
    int pam_status = PAM_SYSTEM_ERR;
    struct be_req *breq =
            tevent_req_callback_data(req, struct be_req);

    ret = sdap_access_recv(req, &pam_status);
    talloc_zfree(req);
    if (ret != EOK) {
        DEBUG(1, ("Error retrieving access check result.\n"));
        pam_status = PAM_SYSTEM_ERR;
    }

    sdap_access_reply(breq, pam_status);
}