summaryrefslogtreecommitdiffstats
path: root/src/providers/ldap/sdap_child_helpers.c
blob: f2412f9e59a8ee3c6d1651b6b96ce2fd36c4fdd1 (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
/*
    SSSD

    LDAP Backend Module -- child helpers

    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 <sys/wait.h>
#include <pwd.h>
#include <unistd.h>
#include <fcntl.h>

#include "util/util.h"
#include "util/sss_krb5.h"
#include "providers/ldap/ldap_common.h"
#include "providers/ldap/sdap_async_private.h"
#include "util/child_common.h"

#ifndef SSSD_LIBEXEC_PATH
#error "SSSD_LIBEXEC_PATH not defined"
#else
#define LDAP_CHILD SSSD_LIBEXEC_PATH"/ldap_child"
#endif

#ifndef LDAP_CHILD_USER
#define LDAP_CHILD_USER  "nobody"
#endif

struct sdap_child {
    /* child info */
    pid_t pid;
    int read_from_child_fd;
    int write_to_child_fd;
};

static void sdap_close_fd(int *fd)
{
    int ret;

    if (*fd == -1) {
        DEBUG(6, ("fd already closed\n"));
        return;
    }

    ret = close(*fd);
    if (ret) {
        ret = errno;
        DEBUG(2, ("Closing fd %d, return error %d (%s)\n",
                  *fd, ret, strerror(ret)));
    }

    *fd = -1;
}

static int sdap_child_destructor(void *ptr)
{
    struct sdap_child *child = talloc_get_type(ptr, struct sdap_child);

    child_cleanup(child->read_from_child_fd, child->write_to_child_fd);

    return 0;
}

static errno_t sdap_fork_child(struct tevent_context *ev,
                               struct sdap_child *child)
{
    int pipefd_to_child[2];
    int pipefd_from_child[2];
    pid_t pid;
    int ret;
    errno_t err;

    ret = pipe(pipefd_from_child);
    if (ret == -1) {
        err = errno;
        DEBUG(1, ("pipe failed [%d][%s].\n", err, strerror(err)));
        return err;
    }
    ret = pipe(pipefd_to_child);
    if (ret == -1) {
        err = errno;
        DEBUG(1, ("pipe failed [%d][%s].\n", err, strerror(err)));
        return err;
    }

    pid = fork();

    if (pid == 0) { /* child */
        err = exec_child(child,
                         pipefd_to_child, pipefd_from_child,
                         LDAP_CHILD, ldap_child_debug_fd);
        DEBUG(SSSDBG_CRIT_FAILURE, ("Could not exec LDAP child: [%d][%s].\n",
                                    err, strerror(err)));
        return err;
    } else if (pid > 0) { /* parent */
        child->pid = pid;
        child->read_from_child_fd = pipefd_from_child[0];
        close(pipefd_from_child[1]);
        child->write_to_child_fd = pipefd_to_child[1];
        close(pipefd_to_child[0]);
        fd_nonblocking(child->read_from_child_fd);
        fd_nonblocking(child->write_to_child_fd);

        ret = child_handler_setup(ev, pid, NULL, NULL);
        if (ret != EOK) {
            return ret;
        }

    } else { /* error */
        err = errno;
        DEBUG(1, ("fork failed [%d][%s].\n", err, strerror(err)));
        return err;
    }

    return EOK;
}

static errno_t create_tgt_req_send_buffer(TALLOC_CTX *mem_ctx,
                                          const char *realm_str,
                                          const char *princ_str,
                                          const char *keytab_name,
                                          int32_t lifetime,
                                          struct io_buffer **io_buf)
{
    struct io_buffer *buf;
    size_t rp;

    buf = talloc(mem_ctx, struct io_buffer);
    if (buf == NULL) {
        DEBUG(1, ("talloc failed.\n"));
        return ENOMEM;
    }

    buf->size = 4 * sizeof(uint32_t);
    if (realm_str) {
        buf->size += strlen(realm_str);
    }
    if (princ_str) {
        buf->size += strlen(princ_str);
    }
    if (keytab_name) {
        buf->size += strlen(keytab_name);
    }

    DEBUG(7, ("buffer size: %d\n", buf->size));

    buf->data = talloc_size(buf, buf->size);
    if (buf->data == NULL) {
        DEBUG(1, ("talloc_size failed.\n"));
        talloc_free(buf);
        return ENOMEM;
    }

    rp = 0;

    /* realm */
    if (realm_str) {
        SAFEALIGN_SET_UINT32(&buf->data[rp], strlen(realm_str), &rp);
        safealign_memcpy(&buf->data[rp], realm_str, strlen(realm_str), &rp);
    } else {
        SAFEALIGN_SET_UINT32(&buf->data[rp], 0, &rp);
    }

    /* principal */
    if (princ_str) {
        SAFEALIGN_SET_UINT32(&buf->data[rp], strlen(princ_str), &rp);
        safealign_memcpy(&buf->data[rp], princ_str, strlen(princ_str), &rp);
    } else {
        SAFEALIGN_SET_UINT32(&buf->data[rp], 0, &rp);
    }

    /* keytab */
    if (keytab_name) {
        SAFEALIGN_SET_UINT32(&buf->data[rp], strlen(keytab_name), &rp);
        safealign_memcpy(&buf->data[rp], keytab_name, strlen(keytab_name), &rp);
    } else {
        SAFEALIGN_SET_UINT32(&buf->data[rp], 0, &rp);
    }

    /* lifetime */
    SAFEALIGN_SET_UINT32(&buf->data[rp], lifetime, &rp);

    *io_buf = buf;
    return EOK;
}

static int parse_child_response(TALLOC_CTX *mem_ctx,
                                uint8_t *buf, ssize_t size,
                                int  *result, krb5_error_code *kerr,
                                char **ccache, time_t *expire_time_out)
{
    size_t p = 0;
    uint32_t len;
    uint32_t res;
    char *ccn;
    time_t expire_time;
    krb5_error_code krberr;

    /* operation result code */
    SAFEALIGN_COPY_UINT32_CHECK(&res, buf + p, size, &p);

    /* krb5 error code */
    safealign_memcpy(&krberr, buf+p, sizeof(krberr), &p);

    /* ccache name size */
    SAFEALIGN_COPY_UINT32_CHECK(&len, buf + p, size, &p);

    if ((p + len ) > size) return EINVAL;

    ccn = talloc_size(mem_ctx, sizeof(char) * (len + 1));
    if (ccn == NULL) {
        DEBUG(1, ("talloc_size failed.\n"));
        return ENOMEM;
    }
    safealign_memcpy(ccn, buf+p, sizeof(char) * len, &p);
    ccn[len] = '\0';

    if (p + sizeof(time_t) > size) {
        talloc_free(ccn);
        return EINVAL;
    }
    safealign_memcpy(&expire_time, buf+p, sizeof(time_t), &p);

    *result = res;
    *ccache = ccn;
    *expire_time_out = expire_time;
    *kerr = krberr;
    return EOK;
}

/* ==The-public-async-interface============================================*/

struct sdap_get_tgt_state {
    struct tevent_context *ev;
    struct sdap_child *child;
    ssize_t len;
    uint8_t *buf;
};

static errno_t set_tgt_child_timeout(struct tevent_req *req,
                                     struct tevent_context *ev,
                                     int timeout);
static void sdap_get_tgt_step(struct tevent_req *subreq);
static void sdap_get_tgt_done(struct tevent_req *subreq);

struct tevent_req *sdap_get_tgt_send(TALLOC_CTX *mem_ctx,
                                     struct tevent_context *ev,
                                     const char *realm_str,
                                     const char *princ_str,
                                     const char *keytab_name,
                                     int32_t lifetime,
                                     int timeout)
{
    struct tevent_req *req, *subreq;
    struct sdap_get_tgt_state *state;
    struct io_buffer *buf;
    int ret;

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

    state->ev = ev;

    state->child = talloc_zero(state, struct sdap_child);
    if (!state->child) {
        ret = ENOMEM;
        goto fail;
    }

    state->child->read_from_child_fd = -1;
    state->child->write_to_child_fd = -1;
    talloc_set_destructor((TALLOC_CTX *)state->child, sdap_child_destructor);

    /* prepare the data to pass to child */
    ret = create_tgt_req_send_buffer(state,
                                     realm_str, princ_str, keytab_name, lifetime,
                                     &buf);
    if (ret != EOK) {
        DEBUG(1, ("create_tgt_req_send_buffer failed.\n"));
        goto fail;
    }

    ret = sdap_fork_child(state->ev, state->child);
    if (ret != EOK) {
        DEBUG(1, ("sdap_fork_child failed.\n"));
        goto fail;
    }

    ret = set_tgt_child_timeout(req, ev, timeout);
    if (ret != EOK) {
        DEBUG(1, ("activate_child_timeout_handler failed.\n"));
        goto fail;
    }

    subreq = write_pipe_send(state, ev, buf->data, buf->size,
                             state->child->write_to_child_fd);
    if (!subreq) {
        ret = ENOMEM;
        goto fail;
    }
    tevent_req_set_callback(subreq, sdap_get_tgt_step, req);

    return req;

fail:
    tevent_req_error(req, ret);
    tevent_req_post(req, ev);
    return req;
}

static void sdap_get_tgt_step(struct tevent_req *subreq)
{
    struct tevent_req *req = tevent_req_callback_data(subreq,
                                                      struct tevent_req);
    struct sdap_get_tgt_state *state = tevent_req_data(req,
                                                  struct sdap_get_tgt_state);
    int ret;

    ret = write_pipe_recv(subreq);
    talloc_zfree(subreq);
    if (ret != EOK) {
        tevent_req_error(req, ret);
        return;
    }

    sdap_close_fd(&state->child->write_to_child_fd);

    subreq = read_pipe_send(state, state->ev,
                            state->child->read_from_child_fd);
    if (!subreq) {
        tevent_req_error(req, ENOMEM);
        return;
    }
    tevent_req_set_callback(subreq, sdap_get_tgt_done, req);
}

static void sdap_get_tgt_done(struct tevent_req *subreq)
{
    struct tevent_req *req = tevent_req_callback_data(subreq,
                                                      struct tevent_req);
    struct sdap_get_tgt_state *state = tevent_req_data(req,
                                                  struct sdap_get_tgt_state);
    int ret;

    ret = read_pipe_recv(subreq, state, &state->buf, &state->len);
    talloc_zfree(subreq);
    if (ret != EOK) {
        tevent_req_error(req, ret);
        return;
    }

    sdap_close_fd(&state->child->read_from_child_fd);

    tevent_req_done(req);
}

int sdap_get_tgt_recv(struct tevent_req *req,
                      TALLOC_CTX *mem_ctx,
                      int  *result,
                      krb5_error_code *kerr,
                      char **ccname,
                      time_t *expire_time_out)
{
    struct sdap_get_tgt_state *state = tevent_req_data(req,
                                             struct sdap_get_tgt_state);
    char *ccn;
    time_t expire_time;
    int  res;
    int ret;
    krb5_error_code krberr;

    TEVENT_REQ_RETURN_ON_ERROR(req);

    ret = parse_child_response(mem_ctx, state->buf, state->len,
                               &res, &krberr, &ccn, &expire_time);
    if (ret != EOK) {
        DEBUG(1, ("Cannot parse child response: [%d][%s]\n", ret, strerror(ret)));
        return ret;
    }

    DEBUG(6, ("Child responded: %d [%s], expired on [%ld]\n", res, ccn, (long)expire_time));
    *result = res;
    *kerr = krberr;
    *ccname = ccn;
    *expire_time_out = expire_time;
    return EOK;
}



static void get_tgt_timeout_handler(struct tevent_context *ev,
                                    struct tevent_timer *te,
                                    struct timeval tv, void *pvt)
{
    struct tevent_req *req = talloc_get_type(pvt, struct tevent_req);
    struct sdap_get_tgt_state *state = tevent_req_data(req,
                                            struct sdap_get_tgt_state);
    int ret;

    DEBUG(9, ("timeout for tgt child [%d] reached.\n", state->child->pid));

    ret = kill(state->child->pid, SIGKILL);
    if (ret == -1) {
        DEBUG(1, ("kill failed [%d][%s].\n", errno, strerror(errno)));
    }

    tevent_req_error(req, ETIMEDOUT);
}

static errno_t set_tgt_child_timeout(struct tevent_req *req,
                                     struct tevent_context *ev,
                                     int timeout)
{
    struct tevent_timer *te;
    struct timeval tv;

    DEBUG(6, ("Setting %d seconds timeout for tgt child\n", timeout));

    tv = tevent_timeval_current_ofs(timeout, 0);

    te = tevent_add_timer(ev, req, tv, get_tgt_timeout_handler, req);
    if (te == NULL) {
        DEBUG(1, ("tevent_add_timer failed.\n"));
        return ENOMEM;
    }

    return EOK;
}



/* Setup child logging */
int setup_child(struct sdap_id_ctx *ctx)
{
    int ret;
    unsigned v;
    FILE *debug_filep;

    if (debug_to_file != 0 && ldap_child_debug_fd == -1) {
        ret = open_debug_file_ex(LDAP_CHILD_LOG_FILE, &debug_filep);
        if (ret != EOK) {
            DEBUG(0, ("Error setting up logging (%d) [%s]\n",
                        ret, strerror(ret)));
            return ret;
        }

        ldap_child_debug_fd = fileno(debug_filep);
        if (ldap_child_debug_fd == -1) {
            DEBUG(0, ("fileno failed [%d][%s]\n", errno, strerror(errno)));
            ret = errno;
            return ret;
        }

        v = fcntl(ldap_child_debug_fd, F_GETFD, 0);
        fcntl(ldap_child_debug_fd, F_SETFD, v & ~FD_CLOEXEC);
    }

    return EOK;
}