summaryrefslogtreecommitdiff
path: root/src/providers/ldap/ldap_child.c
blob: 160cc1ce464f4ff7ec1cfd9fc4eb31e2ddf4c5fe (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
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
/*
    SSSD

    LDAP Backend Module -- prime ccache with TGT in a child process

    Authors:
        Jakub Hrozek <jhrozek@redhat.com>

    Copyright (C) 2009 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/types.h>
#include <unistd.h>
#include <sys/stat.h>
#include <popt.h>

#include <security/pam_modules.h>

#include "util/util.h"
#include "util/sss_krb5.h"
#include "util/child_common.h"
#include "providers/dp_backend.h"

static krb5_context krb5_error_ctx;

struct input_buffer {
    const char *realm_str;
    const char *princ_str;
    const char *keytab_name;
    krb5_deltat lifetime;
};

static errno_t unpack_buffer(uint8_t *buf, size_t size,
                             struct input_buffer *ibuf)
{
    size_t p = 0;
    uint32_t len;

    DEBUG(7, ("total buffer size: %d\n", size));

    /* realm_str size and length */
    SAFEALIGN_COPY_UINT32_CHECK(&len, buf + p, size, &p);

    DEBUG(7, ("realm_str size: %d\n", len));
    if (len) {
        if ((p + len ) > size) return EINVAL;
        ibuf->realm_str = talloc_strndup(ibuf, (char *)(buf + p), len);
        DEBUG(7, ("got realm_str: %s\n", ibuf->realm_str));
        if (ibuf->realm_str == NULL) return ENOMEM;
        p += len;
    }

    /* princ_str size and length */
    SAFEALIGN_COPY_UINT32_CHECK(&len, buf + p, size, &p);

    DEBUG(7, ("princ_str size: %d\n", len));
    if (len) {
        if ((p + len ) > size) return EINVAL;
        ibuf->princ_str = talloc_strndup(ibuf, (char *)(buf + p), len);
        DEBUG(7, ("got princ_str: %s\n", ibuf->princ_str));
        if (ibuf->princ_str == NULL) return ENOMEM;
        p += len;
    }

    /* keytab_name size and length */
    SAFEALIGN_COPY_UINT32_CHECK(&len, buf + p, size, &p);

    DEBUG(7, ("keytab_name size: %d\n", len));
    if (len) {
        if ((p + len ) > size) return EINVAL;
        ibuf->keytab_name = talloc_strndup(ibuf, (char *)(buf + p), len);
        DEBUG(7, ("got keytab_name: %s\n", ibuf->keytab_name));
        if (ibuf->keytab_name == NULL) return ENOMEM;
        p += len;
    }

    /* ticket lifetime */
    SAFEALIGN_COPY_INT32_CHECK(&ibuf->lifetime, buf + p, size, &p);
    DEBUG(7, ("lifetime: %d\n", ibuf->lifetime));

    return EOK;
}

static int pack_buffer(struct response *r, int result, krb5_error_code krberr,
                       const char *msg, time_t expire_time)
{
    int len;
    size_t p = 0;

    len = strlen(msg);
    r->size = 2 * sizeof(uint32_t) + sizeof(krb5_error_code) +
              len + sizeof(time_t);

    r->buf = talloc_array(r, uint8_t, r->size);
    if(!r->buf) {
        return ENOMEM;
    }

    /* result */
    SAFEALIGN_SET_UINT32(&r->buf[p], result, &p);

    /* krb5 error code */
    safealign_memcpy(&r->buf[p], &krberr, sizeof(krberr), &p);

    /* message size */
    SAFEALIGN_SET_UINT32(&r->buf[p], len, &p);

    /* message itself */
    safealign_memcpy(&r->buf[p], msg, len, &p);

    /* ticket expiration time */
    safealign_memcpy(&r->buf[p], &expire_time, sizeof(expire_time), &p);

    return EOK;
}

static krb5_error_code ldap_child_get_tgt_sync(TALLOC_CTX *memctx,
                                               const char *realm_str,
                                               const char *princ_str,
                                               const char *keytab_name,
                                               const krb5_deltat lifetime,
                                               const char **ccname_out,
                                               time_t *expire_time_out)
{
    char *ccname;
    char *realm_name = NULL;
    char *full_princ = NULL;
    char *default_realm = NULL;
    char *tmp_str = NULL;
    krb5_context context = NULL;
    krb5_keytab keytab = NULL;
    krb5_ccache ccache = NULL;
    krb5_principal kprinc;
    krb5_creds my_creds;
    krb5_get_init_creds_opt options;
    krb5_error_code krberr;
    krb5_timestamp kdc_time_offset;
    int canonicalize = 0;
    int kdc_time_offset_usec;
    int ret;

    krberr = krb5_init_context(&context);
    if (krberr) {
        DEBUG(2, ("Failed to init kerberos context\n"));
        return krberr;
    }

    if (!realm_str) {
        krberr = krb5_get_default_realm(context, &default_realm);
        if (krberr) {
            DEBUG(2, ("Failed to get default realm name: %s\n",
                      sss_krb5_get_error_message(context, krberr)));
            goto done;
        }

        realm_name = talloc_strdup(memctx, default_realm);
        krb5_free_default_realm(context, default_realm);
        if (!realm_name) {
            krberr = KRB5KRB_ERR_GENERIC;
            goto done;
        }

    } else {
        realm_name = talloc_strdup(memctx, realm_str);
        if (!realm_name) {
            krberr = KRB5KRB_ERR_GENERIC;
            goto done;
        }
    }

    if (princ_str) {
        if (!strchr(princ_str, '@')) {
            full_princ = talloc_asprintf(memctx, "%s@%s",
                                         princ_str, realm_name);
        } else {
            full_princ = talloc_strdup(memctx, princ_str);
        }
    } else {
        char hostname[512];

        ret = gethostname(hostname, 511);
        if (ret == -1) {
            krberr = KRB5KRB_ERR_GENERIC;
            goto done;
        }
        hostname[511] = '\0';

        ret = select_principal_from_keytab(memctx, hostname, realm_name,
                                           keytab_name, &full_princ, NULL, NULL);
        if (ret) goto done;
    }
    if (!full_princ) {
        krberr = KRB5KRB_ERR_GENERIC;
        goto done;
    }
    DEBUG(4, ("Principal name is: [%s]\n", full_princ));

    krberr = krb5_parse_name(context, full_princ, &kprinc);
    if (krberr) {
        DEBUG(2, ("Unable to build principal: %s\n",
                  sss_krb5_get_error_message(context, krberr)));
        goto done;
    }

    if (keytab_name) {
        krberr = krb5_kt_resolve(context, keytab_name, &keytab);
    } else {
        krberr = krb5_kt_default(context, &keytab);
    }
    if (krberr) {
        DEBUG(0, ("Failed to read keytab file: %s\n",
                  sss_krb5_get_error_message(context, krberr)));
        goto done;
    }

    /* Verify the keytab */
    ret = sss_krb5_verify_keytab_ex(full_princ, keytab_name, context, keytab);
    if (ret) {
        DEBUG(2, ("Unable to verify principal is present in the keytab\n"));
        krberr = KRB5_KT_IOERR;
        goto done;
    }

    ccname = talloc_asprintf(memctx, "FILE:%s/ccache_%s", DB_PATH, realm_name);
    if (!ccname) {
        krberr = KRB5KRB_ERR_GENERIC;
        goto done;
    }

    krberr = krb5_cc_resolve(context, ccname, &ccache);
    if (krberr) {
        DEBUG(2, ("Failed to set cache name: %s\n",
                  sss_krb5_get_error_message(context, krberr)));
        goto done;
    }

    memset(&my_creds, 0, sizeof(my_creds));
    memset(&options, 0, sizeof(options));

    krb5_get_init_creds_opt_set_address_list(&options, NULL);
    krb5_get_init_creds_opt_set_forwardable(&options, 0);
    krb5_get_init_creds_opt_set_proxiable(&options, 0);
    krb5_get_init_creds_opt_set_tkt_life(&options, lifetime);

    tmp_str = getenv("KRB5_CANONICALIZE");
    if (tmp_str != NULL && strcasecmp(tmp_str, "true") == 0) {
        canonicalize = 1;
    }
    sss_krb5_get_init_creds_opt_set_canonicalize(&options, canonicalize);

    krberr = krb5_get_init_creds_keytab(context, &my_creds, kprinc,
                                        keytab, 0, NULL, &options);

    if (krberr) {
        DEBUG(0, ("Failed to init credentials: %s\n",
                  sss_krb5_get_error_message(context, krberr)));
        sss_log(SSS_LOG_ERR, "Failed to initialize credentials using keytab [%s]: %s. "
                             "Unable to create GSSAPI-encrypted LDAP connection.",
                             keytab_name, sss_krb5_get_error_message(context, krberr));
        goto done;
    }

    krberr = krb5_cc_initialize(context, ccache, kprinc);
    if (krberr) {
        DEBUG(2, ("Failed to init ccache: %s\n",
                  sss_krb5_get_error_message(context, krberr)));
        goto done;
    }

    krberr = krb5_cc_store_cred(context, ccache, &my_creds);
    if (krberr) {
        DEBUG(2, ("Failed to store creds: %s\n",
                  sss_krb5_get_error_message(context, krberr)));
        goto done;
    }

    krberr = krb5_get_time_offsets(context, &kdc_time_offset, &kdc_time_offset_usec);
    if (krberr) {
        DEBUG(2, ("Failed to get KDC time offset: %s\n",
                  sss_krb5_get_error_message(context, krberr)));
        kdc_time_offset = 0;
    } else {
        if (kdc_time_offset_usec > 0) {
            kdc_time_offset++;
        }
    }

    krberr = 0;
    *ccname_out = ccname;
    *expire_time_out = my_creds.times.endtime - kdc_time_offset;

done:
    if (keytab) krb5_kt_close(context, keytab);
    if (context) krb5_free_context(context);
    return krberr;
}

static int prepare_response(TALLOC_CTX *mem_ctx,
                            const char *ccname,
                            time_t expire_time,
                            krb5_error_code kerr,
                            struct response **rsp)
{
    int ret;
    struct response *r = NULL;
    const char *krb5_msg = NULL;

    r = talloc_zero(mem_ctx, struct response);
    if (!r) return ENOMEM;

    r->buf = NULL;
    r->size = 0;

    if (kerr == 0) {
        ret = pack_buffer(r, EOK, kerr, ccname, expire_time);
    } else {
        krb5_msg = sss_krb5_get_error_message(krb5_error_ctx, kerr);
        if (krb5_msg == NULL) {
            DEBUG(1, ("sss_krb5_get_error_message failed.\n"));
            return ENOMEM;
        }

        ret = pack_buffer(r, EFAULT, kerr, krb5_msg, 0);
        sss_krb5_free_error_message(krb5_error_ctx, krb5_msg);
    }

    if (ret != EOK) {
        DEBUG(1, ("pack_buffer failed\n"));
        return ret;
    }

    *rsp = r;
    return EOK;
}

int main(int argc, const char *argv[])
{
    int ret;
    int kerr;
    int opt;
    int debug_fd = -1;
    poptContext pc;
    TALLOC_CTX *main_ctx;
    uint8_t *buf = NULL;
    ssize_t len = 0;
    const char *ccname = NULL;
    time_t expire_time = 0;
    struct input_buffer *ibuf = NULL;
    struct response *resp = NULL;
    size_t written;

    struct poptOption long_options[] = {
        POPT_AUTOHELP
        {"debug-level", 'd', POPT_ARG_INT, &debug_level, 0,
         _("Debug level"), NULL},
        {"debug-timestamps", 0, POPT_ARG_INT, &debug_timestamps, 0,
         _("Add debug timestamps"), NULL},
        {"debug-microseconds", 0, POPT_ARG_INT, &debug_microseconds, 0,
         _("Show timestamps with microseconds"), NULL},
        {"debug-fd", 0, POPT_ARG_INT, &debug_fd, 0,
         _("An open file descriptor for the debug logs"), NULL},
        POPT_TABLEEND
    };

    /* Set debug level to invalid value so we can deside if -d 0 was used. */
    debug_level = SSSDBG_INVALID;

    pc = poptGetContext(argv[0], argc, argv, long_options, 0);
    while((opt = poptGetNextOpt(pc)) != -1) {
        switch(opt) {
        default:
        fprintf(stderr, "\nInvalid option %s: %s\n\n",
                  poptBadOption(pc, 0), poptStrerror(opt));
            poptPrintUsage(pc, stderr, 0);
            _exit(-1);
        }
    }

    poptFreeContext(pc);

    CONVERT_AND_SET_DEBUG_LEVEL(debug_level);

    DEBUG(7, ("ldap_child started.\n"));

    main_ctx = talloc_new(NULL);
    if (main_ctx == NULL) {
        DEBUG(1, ("talloc_new failed.\n"));
        _exit(-1);
    }

    debug_prg_name = talloc_asprintf(main_ctx, "[sssd[ldap_child[%d]]]", getpid());

    if (debug_fd != -1) {
        ret = set_debug_file_from_fd(debug_fd);
        if (ret != EOK) {
            DEBUG(1, ("set_debug_file_from_fd failed.\n"));
        }
    }

    buf = talloc_size(main_ctx, sizeof(uint8_t)*IN_BUF_SIZE);
    if (buf == NULL) {
        DEBUG(1, ("talloc_size failed.\n"));
        goto fail;
    }

    ibuf = talloc_zero(main_ctx, struct input_buffer);
    if (ibuf == NULL) {
        DEBUG(1, ("talloc_size failed.\n"));
        goto fail;
    }

    while ((ret = read(STDIN_FILENO, buf + len, IN_BUF_SIZE - len)) != 0) {
        if (ret == -1) {
            if (errno == EINTR || errno == EAGAIN) {
                continue;
            }
            DEBUG(1, ("read failed [%d][%s].\n", errno, strerror(errno)));
            goto fail;
        } else if (ret > 0) {
            len += ret;
            if (len > IN_BUF_SIZE) {
                DEBUG(1, ("read too much, this should never happen.\n"));
                goto fail;
            }
            continue;
        } else {
            DEBUG(1, ("unexpected return code of read [%d].\n", ret));
            goto fail;
        }
    }
    close(STDIN_FILENO);

    ret = unpack_buffer(buf, len, ibuf);
    if (ret != EOK) {
        DEBUG(1, ("unpack_buffer failed.[%d][%s].\n", ret, strerror(ret)));
        goto fail;
    }

    kerr = ldap_child_get_tgt_sync(main_ctx,
                                   ibuf->realm_str, ibuf->princ_str,
                                   ibuf->keytab_name, ibuf->lifetime,
                                   &ccname, &expire_time);
    if (kerr != EOK) {
        DEBUG(1, ("ldap_child_get_tgt_sync failed.\n"));
        /* Do not return, must report failure */
    }

    ret = prepare_response(main_ctx, ccname, expire_time, kerr, &resp);
    if (ret != EOK) {
        DEBUG(1, ("prepare_response failed. [%d][%s].\n", ret, strerror(ret)));
        return ENOMEM;
    }

    written = 0;
    while (written < resp->size) {
        ret = write(STDOUT_FILENO, resp->buf + written, resp->size - written);
        if (ret == -1) {
            if (errno == EAGAIN || errno == EINTR) {
                continue;
            }
            ret = errno;
            DEBUG(1, ("write failed [%d][%s].\n", ret, strerror(ret)));
            return ret;
        }
        written += ret;
    }

    close(STDOUT_FILENO);
    talloc_free(main_ctx);
    _exit(0);

fail:
    close(STDOUT_FILENO);
    talloc_free(main_ctx);
    _exit(-1);
}