summaryrefslogtreecommitdiff
path: root/src/providers/ldap/sdap_idmap.c
blob: e51fcc6b4623897a8e02a3a626fbc7484f99873b (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
/*
    SSSD

    Authors:
        Stephen Gallagher <sgallagh@redhat.com>

    Copyright (C) 2012 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 "util/util.h"
#include "util/dlinklist.h"
#include "util/murmurhash3.h"
#include "providers/ldap/sdap_idmap.h"

static void *
sdap_idmap_talloc(size_t size, void *pvt)
{
    return talloc_size(pvt, size);
}

static void
sdap_idmap_talloc_free(void *ptr, void *pvt)
{
    talloc_free(ptr);
}

errno_t
sdap_idmap_init(TALLOC_CTX *mem_ctx,
                struct sdap_id_ctx *id_ctx,
                struct sdap_idmap_ctx **_idmap_ctx)
{
    errno_t ret;
    TALLOC_CTX *tmp_ctx;
    enum idmap_error_code err;
    size_t i;
    struct ldb_result *res;
    const char *dom_name;
    const char *sid_str;
    id_t slice_num;
    struct sdap_idmap_ctx *idmap_ctx = NULL;
    struct sysdb_ctx *sysdb = id_ctx->be->sysdb;

    tmp_ctx = talloc_new(NULL);
    if (!tmp_ctx) return ENOMEM;

    idmap_ctx = talloc_zero(tmp_ctx, struct sdap_idmap_ctx);
    if (!idmap_ctx) {
        ret = ENOMEM;
        goto done;
    }
    idmap_ctx->id_ctx = id_ctx;

    /* Initialize the map */
    err = sss_idmap_init(sdap_idmap_talloc, idmap_ctx,
                         sdap_idmap_talloc_free,
                         &idmap_ctx->map);
    if (err != IDMAP_SUCCESS) {
        DEBUG(SSSDBG_CRIT_FAILURE,
              ("Could not initialize the ID map: [%s]\n",
               idmap_error_string(err)));
        if (err == IDMAP_OUT_OF_MEMORY) {
            ret = ENOMEM;
        } else {
            ret = EINVAL;
        }
        goto done;
    }

    /* Read in any existing mappings from the cache */
    ret = sysdb_idmap_get_mappings(tmp_ctx, sysdb, &res);
    if (ret != EOK && ret != ENOENT) {
        DEBUG(SSSDBG_FATAL_FAILURE,
              ("Could not read ID mappings from the cache: [%s]\n",
               strerror(ret)));
        goto done;
    }

    if (ret == EOK && res->count > 0) {
        DEBUG(SSSDBG_CONF_SETTINGS,
              ("Initializing [%d] domains for ID-mapping\n", res->count));

        for (i = 0; i < res->count; i++) {
            dom_name = ldb_msg_find_attr_as_string(res->msgs[i],
                                                   SYSDB_NAME,
                                                   NULL);
            if (!dom_name) {
                /* This should never happen */
                ret = EINVAL;
                goto done;
            }

            sid_str = ldb_msg_find_attr_as_string(res->msgs[i],
                                                  SYSDB_IDMAP_SID_ATTR,
                                                  NULL);
            if (!sid_str) {
                /* This should never happen */
                ret = EINVAL;
                goto done;
            }

            slice_num = ldb_msg_find_attr_as_int(res->msgs[i],
                                                 SYSDB_IDMAP_SLICE_ATTR,
                                                 -1);
            if (slice_num == -1) {
                /* This should never happen */
                ret = EINVAL;
                goto done;
            }

            ret = sdap_idmap_add_domain(idmap_ctx, dom_name,
                                        sid_str, slice_num);
            if (ret != EOK) {
                DEBUG(SSSDBG_CRIT_FAILURE,
                      ("Could not add domain [%s][%s][%u] to ID map: [%s]\n",
                       dom_name, sid_str, slice_num, strerror(ret)));
                goto done;
            }
        }
    } else {
        /* This is the first time we're setting up id-mapping
         * Store the default domain as slice 0
         */
        dom_name = dp_opt_get_string(idmap_ctx->id_ctx->opts->basic, SDAP_IDMAP_DEFAULT_DOMAIN);
        if (!dom_name) {
            /* If it's not explicitly specified, use the SSSD domain name */
            dom_name = idmap_ctx->id_ctx->be->domain->name;
            ret = dp_opt_set_string(idmap_ctx->id_ctx->opts->basic,
                                    SDAP_IDMAP_DEFAULT_DOMAIN,
                                    dom_name);
            if (ret != EOK) goto done;
        }

        sid_str = dp_opt_get_string(idmap_ctx->id_ctx->opts->basic, SDAP_IDMAP_DEFAULT_DOMAIN_SID);
        if (sid_str) {
            /* Set the default domain as slice 0 */
            ret = sdap_idmap_add_domain(idmap_ctx, dom_name,
                                        sid_str, 0);
            if (ret != EOK) {
                DEBUG(SSSDBG_CRIT_FAILURE,
                      ("Could not add domain [%s][%s][%u] to ID map: [%s]\n",
                       dom_name, sid_str, 0, strerror(ret)));
                goto done;
            }
        } else {
            if (dp_opt_get_bool(idmap_ctx->id_ctx->opts->basic, SDAP_IDMAP_AUTORID_COMPAT)) {
                /* In autorid compatibility mode, we MUST have a slice 0 */
                DEBUG(SSSDBG_CRIT_FAILURE,
                      ("WARNING: Autorid compatibility mode selected, "
                       "but %s is not set. UID/GID values may differ "
                       "between clients.\n",
                       idmap_ctx->id_ctx->opts->basic[SDAP_IDMAP_DEFAULT_DOMAIN_SID].opt_name));
            }
            /* Otherwise, we'll just fall back to hash values as they are seen */
        }
    }

    *_idmap_ctx = talloc_steal(mem_ctx, idmap_ctx);
    ret = EOK;

done:
    talloc_free(tmp_ctx);
    return ret;
}

errno_t
sdap_idmap_add_domain(struct sdap_idmap_ctx *idmap_ctx,
                      const char *dom_name,
                      const char *dom_sid,
                      id_t slice)
{
    errno_t ret;
    struct sdap_idmap_slice *new_slice;
    id_t idmap_lower;
    id_t idmap_upper;
    id_t rangesize;
    id_t max_slices;
    id_t orig_slice;
    uint32_t hash_val;
    struct sdap_idmap_slice *s;
    struct sss_idmap_range range;
    enum idmap_error_code err;

    idmap_lower = dp_opt_get_int(idmap_ctx->id_ctx->opts->basic,
                                 SDAP_IDMAP_LOWER);
    idmap_upper = dp_opt_get_int(idmap_ctx->id_ctx->opts->basic,
                                 SDAP_IDMAP_UPPER);
    rangesize = dp_opt_get_int(idmap_ctx->id_ctx->opts->basic,
                               SDAP_IDMAP_RANGESIZE);

    /* Validate that the values make sense */
    if (rangesize <= 0
            || idmap_upper <= idmap_lower
            || (idmap_upper-idmap_lower) < rangesize)
    {
        DEBUG(SSSDBG_CRIT_FAILURE,
              ("Invalid settings for range selection: [%d][%d][%d]\n",
               idmap_lower, idmap_upper, rangesize));
        return EINVAL;
    }

    max_slices = (idmap_upper - idmap_lower) / rangesize;
    if (((idmap_upper - idmap_lower) % rangesize) != 0) {
        DEBUG(SSSDBG_CONF_SETTINGS,
              ("Range size does not divide evenly. Uppermost range will "
               "not be used\n"));
    }

    new_slice = talloc_zero(idmap_ctx, struct sdap_idmap_slice);
    if (!new_slice) return ENOMEM;

    if (slice != -1) {
        /* The slice is being set explicitly.
         * This may happen at system startup when we're loading
         * previously-determined slices. In the future, we may also
         * permit configuration to select the slice for a domain
         * explicitly.
         */
        new_slice->slice_num = slice;
    } else {
        /* If slice is -1, we're being asked to pick a new slice */

        if (dp_opt_get_bool(idmap_ctx->id_ctx->opts->basic, SDAP_IDMAP_AUTORID_COMPAT)) {
            /* In autorid compatibility mode, always start at 0 and find the first
             * free value.
             */
            orig_slice = 0;
        } else {
            /* Hash the domain sid string */
            hash_val = murmurhash3(dom_sid, strlen(dom_sid), 0xdeadbeef);

            /* Now get take the modulus of the hash val and the max_slices
             * to determine its optimal position in the range.
             */
            new_slice->slice_num = hash_val % max_slices;
            orig_slice = new_slice->slice_num;
        }
        /* Verify that this slice is not already in use */
        do {
            DLIST_FOR_EACH(s, idmap_ctx->slices) {
                if (s->slice_num == new_slice->slice_num) {
                    /* This slice number matches one already registered
                     * We'll try the next available slot
                     */
                    new_slice->slice_num++;
                    if (new_slice->slice_num > max_slices) {
                        /* loop around to the beginning if necessary */
                        new_slice->slice_num = 0;
                    }
                    break;
                }
            }

            /* Keep trying until s is NULL (meaning we got to the end
             * without matching) or we have run out of slices and gotten
             * back to the first one we tried.
             */
        } while (s && new_slice->slice_num != orig_slice);

        if (s) {
            /* We looped all the way through and found no empty slots */
            DEBUG(SSSDBG_CRIT_FAILURE,
                  ("Could not add domain [%s]: no free slices\n",
                   dom_name));
            ret = ENOSPC;
            goto done;
        }
    }

    DEBUG(SSSDBG_CONF_SETTINGS,
          ("Adding domain [%s] as slice [%d]\n",
           dom_name, new_slice->slice_num));

    DLIST_ADD_END(idmap_ctx->slices, new_slice, struct sdap_idmap_slice *);
    /* Not adding a destructor to remove from this list, because it
     * should never be possible. Removal from this list can only
     * destabilize the system.
     */

    /* Create a range object to add to the mapping */
    range.min = (rangesize * new_slice->slice_num) + idmap_lower;
    range.max = range.min + rangesize;

    if (range.max > idmap_upper) {
        /* This should never happen */
        DEBUG(SSSDBG_CRIT_FAILURE,
              ("BUG: Range maximum exceeds the global maximum: %d > %d\n",
               range.max, idmap_upper));
        ret = EINVAL;
        goto done;
    }

    /* Add this domain to the map */
    err = sss_idmap_add_domain(idmap_ctx->map, dom_name, dom_sid, &range);
    if (err != IDMAP_SUCCESS) {
        DEBUG(SSSDBG_CRIT_FAILURE,
              ("Could not add domain [%s] to the map: [%d]\n",
               dom_name, err));
        ret = EIO;
        goto done;
    }

    /* Add this domain to the SYSDB cache so it will survive reboot */
    ret = sysdb_idmap_store_mapping(idmap_ctx->id_ctx->be->sysdb,
                                    dom_name, dom_sid,
                                    new_slice->slice_num);
done:
    if (ret != EOK) {
        talloc_free(new_slice);
    }
    return ret;
}

errno_t
sdap_idmap_get_dom_sid_from_object(TALLOC_CTX *mem_ctx,
                                   const char *object_sid,
                                   char **dom_sid_str)
{
    const char *p;
    long long a;
    size_t c;
    char *endptr;

    if (object_sid == NULL
            || strncmp(object_sid, DOM_SID_PREFIX, DOM_SID_PREFIX_LEN) != 0) {
        return EINVAL;
    }

    p = object_sid + DOM_SID_PREFIX_LEN;
    c = 0;

    do {
        errno = 0;
        a = strtoull(p, &endptr, 10);
        if (errno != 0 || a > UINT32_MAX) {
            return EINVAL;
        }

        if (*endptr == '-') {
            p = endptr + 1;
        } else {
            return EINVAL;
        }
        c++;
    } while(c < 3);

    /* If we made it here, we are now one character past
     * the last hyphen in the object-sid.
     * Copy the dom-sid substring.
     */
    *dom_sid_str = talloc_strndup(mem_ctx, object_sid,
                                  (endptr-object_sid));
    if (!*dom_sid_str) return ENOMEM;

    return EOK;
}

errno_t
sdap_idmap_sid_to_unix(struct sdap_idmap_ctx *idmap_ctx,
                       const char *sid_str,
                       id_t *id)
{
    errno_t ret;
    enum idmap_error_code err;
    char *dom_sid_str = NULL;

    /* Convert the SID into a UNIX ID */
    err = sss_idmap_sid_to_unix(idmap_ctx->map,
                                sid_str,
                                (uint32_t *)id);
    switch (err) {
    case IDMAP_SUCCESS:
        break;
    case IDMAP_NO_DOMAIN:
        /* This is the first time we've seen this domain
         * Create a new domain for it. We'll use the dom-sid
         * as the domain name for now, since we don't have
         * any way to get the real name.
         */
        ret = sdap_idmap_get_dom_sid_from_object(NULL, sid_str,
                                                 &dom_sid_str);
        if (ret != EOK) {
            DEBUG(SSSDBG_MINOR_FAILURE,
                  ("Could not parse domain SID from [%s]\n", sid_str));
            goto done;
        }

        ret = sdap_idmap_add_domain(idmap_ctx,
                                    dom_sid_str, dom_sid_str,
                                    -1);
        if (ret != EOK) {
            DEBUG(SSSDBG_MINOR_FAILURE,
                  ("Could not add new domain for sid [%s]\n", sid_str));
            goto done;
        }

        /* Now try converting to a UNIX ID again */
        err = sss_idmap_sid_to_unix(idmap_ctx->map,
                                    sid_str,
                                    (uint32_t *)id);
        if (err != IDMAP_SUCCESS) {
            DEBUG(SSSDBG_MINOR_FAILURE,
                  ("Could not convert objectSID [%s] to a UNIX ID\n",
                   sid_str));
            ret = EIO;
            goto done;
        }
        break;
    case IDMAP_BUILTIN_SID:
        DEBUG(SSSDBG_TRACE_FUNC,
              ("Object SID [%s] is a built-in one.\n", sid_str));
        /* ENOTSUP indicates built-in SID */
        ret = ENOTSUP;
        goto done;
        break;
    default:
        DEBUG(SSSDBG_MINOR_FAILURE,
              ("Could not convert objectSID [%s] to a UNIX ID\n",
               sid_str));
        ret = EIO;
        goto done;
    }

    ret = EOK;

done:
    talloc_free(dom_sid_str);
    return ret;
}