summaryrefslogtreecommitdiff
path: root/src/sss_client/common.c
blob: 59eae3b1fe4101383de96f680458467a962c2248 (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
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
/*
 * System Security Services Daemon. NSS client interface
 *
 * Copyright (C) Simo Sorce 2007
 *
 * Winbind derived code:
 * Copyright (C) Tim Potter 2000
 * Copyright (C) Andrew Tridgell 2000
 * Copyright (C) Andrew Bartlett 2002
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "config.h"

#include <nss.h>
#include <security/pam_modules.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <time.h>

#include <libintl.h>
#define _(STRING) dgettext (PACKAGE, STRING)
#include "sss_cli.h"

#if HAVE_PTHREAD
#include <pthread.h>
#endif

/*
* Note we set MSG_NOSIGNAL to avoid
* having to fiddle with signal masks
* but also do not want to die in case
* SIGPIPE gets raised and the application
* does not handle it.
*/
#ifdef MSG_NOSIGNAL
#define SSS_DEFAULT_WRITE_FLAGS MSG_NOSIGNAL
#else
#define SSS_DEFAULT_WRITE_FLAGS 0
#endif

/* common functions */

int sss_cli_sd = -1; /* the sss client socket descriptor */
struct stat sss_cli_sb; /* the sss client stat buffer */

#if HAVE_FUNCTION_ATTRIBUTE_DESTRUCTOR
__attribute__((destructor))
#endif
static void sss_cli_close_socket(void)
{
    if (sss_cli_sd != -1) {
        close(sss_cli_sd);
        sss_cli_sd = -1;
    }
}

/* Requests:
 *
 * byte 0-3: 32bit unsigned with length (the complete packet length: 0 to X)
 * byte 4-7: 32bit unsigned with command code
 * byte 8-11: 32bit unsigned (reserved)
 * byte 12-15: 32bit unsigned (reserved)
 * byte 16-X: (optional) request structure associated to the command code used
 */
static enum sss_status sss_cli_send_req(enum sss_cli_command cmd,
                                        struct sss_cli_req_data *rd,
                                        int *errnop)
{
    uint32_t header[4];
    size_t datasent;

    header[0] = SSS_NSS_HEADER_SIZE + (rd?rd->len:0);
    header[1] = cmd;
    header[2] = 0;
    header[3] = 0;

    datasent = 0;

    while (datasent < header[0]) {
        struct pollfd pfd;
        int rdsent;
        int res, error;

        *errnop = 0;
        pfd.fd = sss_cli_sd;
        pfd.events = POLLOUT;

        do {
            errno = 0;
            res = poll(&pfd, 1, SSS_CLI_SOCKET_TIMEOUT);
            error = errno;

            /* If error is EINTR here, we'll try again
             * If it's any other error, we'll catch it
             * below.
             */
        } while (error == EINTR);

        switch (res) {
        case -1:
            *errnop = error;
            break;
        case 0:
            *errnop = ETIME;
            break;
        case 1:
            if (pfd.revents & (POLLERR | POLLHUP | POLLNVAL)) {
                *errnop = EPIPE;
            }
            if (!(pfd.revents & POLLOUT)) {
                *errnop = EBUSY;
            }
            break;
        default: /* more than one avail ?? */
            *errnop = EBADF;
            break;
        }
        if (*errnop) {
            sss_cli_close_socket();
            return SSS_STATUS_UNAVAIL;
        }

        errno = 0;
        if (datasent < SSS_NSS_HEADER_SIZE) {
            res = send(sss_cli_sd,
                       (char *)header + datasent,
                       SSS_NSS_HEADER_SIZE - datasent,
                       SSS_DEFAULT_WRITE_FLAGS);
        } else {
            rdsent = datasent - SSS_NSS_HEADER_SIZE;
            res = send(sss_cli_sd,
                       (const char *)rd->data + rdsent,
                       rd->len - rdsent,
                       SSS_DEFAULT_WRITE_FLAGS);
        }
        error = errno;

        if ((res == -1) || (res == 0)) {
            if ((error == EINTR) || error == EAGAIN) {
                /* If the write was interrupted, go back through
                 * the loop and try again
                 */
                continue;
            }

            /* Write failed */
            sss_cli_close_socket();
            *errnop = error;
            return SSS_STATUS_UNAVAIL;
        }

        datasent += res;
    }

    return SSS_STATUS_SUCCESS;
}

/* Replies:
 *
 * byte 0-3: 32bit unsigned with length (the complete packet length: 0 to X)
 * byte 4-7: 32bit unsigned with command code
 * byte 8-11: 32bit unsigned with the request status (server errno)
 * byte 12-15: 32bit unsigned (reserved)
 * byte 16-X: (optional) reply structure associated to the command code used
 */

static enum sss_status sss_cli_recv_rep(enum sss_cli_command cmd,
                                        uint8_t **_buf, int *_len,
                                        int *errnop)
{
    uint32_t header[4];
    size_t datarecv;
    uint8_t *buf = NULL;
    int len;
    int ret;

    header[0] = SSS_NSS_HEADER_SIZE; /* unitl we know the real lenght */
    header[1] = 0;
    header[2] = 0;
    header[3] = 0;

    datarecv = 0;
    buf = NULL;
    len = 0;
    *errnop = 0;

    while (datarecv < header[0]) {
        struct pollfd pfd;
        int bufrecv;
        int res, error;

        pfd.fd = sss_cli_sd;
        pfd.events = POLLIN;

        do {
            errno = 0;
            res = poll(&pfd, 1, SSS_CLI_SOCKET_TIMEOUT);
            error = errno;

            /* If error is EINTR here, we'll try again
             * If it's any other error, we'll catch it
             * below.
             */
        } while (error == EINTR);

        switch (res) {
        case -1:
            *errnop = error;
            break;
        case 0:
            *errnop = ETIME;
            break;
        case 1:
            if (pfd.revents & (POLLERR | POLLHUP | POLLNVAL)) {
                *errnop = EPIPE;
            }
            if (!(pfd.revents & POLLIN)) {
                *errnop = EBUSY;
            }
            break;
        default: /* more than one avail ?? */
            *errnop = EBADF;
            break;
        }
        if (*errnop) {
            sss_cli_close_socket();
            ret = SSS_STATUS_UNAVAIL;
            goto failed;
        }

        errno = 0;
        if (datarecv < SSS_NSS_HEADER_SIZE) {
            res = read(sss_cli_sd,
                       (char *)header + datarecv,
                       SSS_NSS_HEADER_SIZE - datarecv);
        } else {
            bufrecv = datarecv - SSS_NSS_HEADER_SIZE;
            res = read(sss_cli_sd,
                       (char *) buf + bufrecv,
                       header[0] - datarecv);
        }
        error = errno;

        if ((res == -1) || (res == 0)) {
            if ((error == EINTR) || error == EAGAIN) {
                /* If the read was interrupted, go back through
                 * the loop and try again
                 */
                continue;
            }

            /* Read failed.  I think the only useful thing
             * we can do here is just return -1 and fail
             * since the transaction has failed half way
             * through. */

            sss_cli_close_socket();
            *errnop = error;
            ret = SSS_STATUS_UNAVAIL;
            goto failed;
        }

        datarecv += res;

        if (datarecv == SSS_NSS_HEADER_SIZE && len == 0) {
            /* at this point recv buf is not yet
             * allocated and the header has just
             * been read, do checks and proceed */
            if (header[2] != 0) {
                /* server side error */
                sss_cli_close_socket();
                *errnop = header[2];
                if (*errnop == EAGAIN) {
                    ret = SSS_STATUS_TRYAGAIN;
                    goto failed;
                } else {
                    ret = SSS_STATUS_UNAVAIL;
                    goto failed;
                }
            }
            if (header[1] != cmd) {
                /* wrong command id */
                sss_cli_close_socket();
                *errnop = EBADMSG;
                ret = SSS_STATUS_UNAVAIL;
                goto failed;
            }
            if (header[0] > SSS_NSS_HEADER_SIZE) {
                len = header[0] - SSS_NSS_HEADER_SIZE;
                buf = malloc(len);
                if (!buf) {
                    sss_cli_close_socket();
                    *errnop = ENOMEM;
                    ret = SSS_STATUS_UNAVAIL;
                    goto failed;
                }
            }
        }
    }

    *_len = len;
    *_buf = buf;

    return SSS_STATUS_SUCCESS;

failed:
    free(buf);
    return ret;
}

/* this function will check command codes match and returned length is ok */
/* repbuf and replen report only the data section not the header */
static enum sss_status sss_cli_make_request_nochecks(
                                       enum sss_cli_command cmd,
                                       struct sss_cli_req_data *rd,
                                       uint8_t **repbuf, size_t *replen,
                                       int *errnop)
{
    enum sss_status ret;
    uint8_t *buf = NULL;
    int len = 0;

    /* send data */
    ret = sss_cli_send_req(cmd, rd, errnop);
    if (ret != SSS_STATUS_SUCCESS) {
        return ret;
    }

    /* data sent, now get reply */
    ret = sss_cli_recv_rep(cmd, &buf, &len, errnop);
    if (ret != SSS_STATUS_SUCCESS) {
        return ret;
    }

    /* we got through, now we have the custom data in buf if any,
     * return it if requested */
    if (repbuf && buf) {
        *repbuf = buf;
        if (replen) {
            *replen = len;
        }
    } else {
        free(buf);
        if (replen) {
            *replen = 0;
        }
    }

    return SSS_STATUS_SUCCESS;
}

/* GET_VERSION Reply:
 * 0-3: 32bit unsigned version number
 */

static bool sss_cli_check_version(const char *socket_name)
{
    uint8_t *repbuf = NULL;
    size_t replen;
    enum sss_status nret;
    int errnop;
    uint32_t expected_version;
    uint32_t obtained_version;
    struct sss_cli_req_data req;

    if (strcmp(socket_name, SSS_NSS_SOCKET_NAME) == 0) {
        expected_version = SSS_NSS_PROTOCOL_VERSION;
    } else if (strcmp(socket_name, SSS_PAM_SOCKET_NAME) == 0 ||
               strcmp(socket_name, SSS_PAM_PRIV_SOCKET_NAME) == 0) {
        expected_version = SSS_PAM_PROTOCOL_VERSION;
    } else if (strcmp(socket_name, SSS_SUDO_SOCKET_NAME) == 0) {
        expected_version = SSS_SUDO_PROTOCOL_VERSION;
    } else if (strcmp(socket_name, SSS_AUTOFS_SOCKET_NAME) == 0) {
        expected_version = SSS_AUTOFS_PROTOCOL_VERSION;
    } else if (strcmp(socket_name, SSS_SSH_SOCKET_NAME) == 0) {
        expected_version = SSS_SSH_PROTOCOL_VERSION;
    } else if (strcmp(socket_name, SSS_PAC_SOCKET_NAME) == 0) {
        expected_version = SSS_PAC_PROTOCOL_VERSION;
    } else {
        return false;
    }

    req.len = sizeof(expected_version);
    req.data = &expected_version;

    nret = sss_cli_make_request_nochecks(SSS_GET_VERSION, &req,
                                         &repbuf, &replen, &errnop);
    if (nret != SSS_STATUS_SUCCESS) {
        return false;
    }

    if (!repbuf) {
        return false;
    }

    obtained_version = ((uint32_t *)repbuf)[0];
    free(repbuf);

    return (obtained_version == expected_version);
}

/* this 2 functions are adapted from samba3 winbinbd's wb_common.c */

/* Make sure socket handle isn't stdin (0), stdout(1) or stderr(2) by setting
 * the limit to 3 */
#define RECURSION_LIMIT 3

static int make_nonstd_fd_internals(int fd, int limit)
{
    int new_fd;
    if (fd >= 0 && fd <= 2) {
#ifdef F_DUPFD
        if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
            return -1;
        }
        /* Paranoia */
        if (new_fd < 3) {
            close(new_fd);
            return -1;
        }
        close(fd);
        return new_fd;
#else
        if (limit <= 0)
            return -1;

        new_fd = dup(fd);
        if (new_fd == -1)
            return -1;

        /* use the program stack to hold our list of FDs to close */
        new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
        close(fd);
        return new_fd;
#endif
    }
    return fd;
}

/****************************************************************************
 Set a fd into blocking/nonblocking mode. Uses POSIX O_NONBLOCK if available,
 else
 if SYSV use O_NDELAY
 if BSD use FNDELAY
 Set close on exec also.
****************************************************************************/

static int make_safe_fd(int fd)
{
    int result, flags;
    int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
    if (new_fd == -1) {
        close(fd);
        return -1;
    }

    /* Socket should be nonblocking. */
#ifdef O_NONBLOCK
#define FLAG_TO_SET O_NONBLOCK
#else
#ifdef SYSV
#define FLAG_TO_SET O_NDELAY
#else /* BSD */
#define FLAG_TO_SET FNDELAY
#endif
#endif

    if ((flags = fcntl(new_fd, F_GETFL)) == -1) {
        close(new_fd);
        return -1;
    }

    flags |= FLAG_TO_SET;
    if (fcntl(new_fd, F_SETFL, flags) == -1) {
        close(new_fd);
        return -1;
    }

#undef FLAG_TO_SET

    /* Socket should be closed on exec() */
#ifdef FD_CLOEXEC
    result = flags = fcntl(new_fd, F_GETFD, 0);
    if (flags >= 0) {
        flags |= FD_CLOEXEC;
        result = fcntl( new_fd, F_SETFD, flags );
    }
    if (result < 0) {
        close(new_fd);
        return -1;
    }
#endif
    return new_fd;
}

static int sss_cli_open_socket(int *errnop, const char *socket_name)
{
    struct sockaddr_un nssaddr;
    bool inprogress = true;
    bool connected = false;
    unsigned int wait_time;
    unsigned int sleep_time;
    time_t start_time = time(NULL);
    int ret;
    int sd;

    memset(&nssaddr, 0, sizeof(struct sockaddr_un));
    nssaddr.sun_family = AF_UNIX;
    strncpy(nssaddr.sun_path, socket_name,
            strlen(socket_name) + 1);

    sd = socket(AF_UNIX, SOCK_STREAM, 0);
    if (sd == -1) {
        *errnop = errno;
        return -1;
    }

    /* set as non-blocking, close on exec, and make sure standard
     * descriptors are not used */
    sd = make_safe_fd(sd);
    if (sd == -1) {
        *errnop = errno;
        return -1;
    }

    /* this piece is adapted from winbind client code */
    wait_time = 0;
    sleep_time = 0;
    while (inprogress) {
        int connect_errno = 0;
        socklen_t errnosize;
        struct pollfd pfd;

        wait_time += sleep_time;

        ret = connect(sd, (struct sockaddr *)&nssaddr,
                      sizeof(nssaddr));
        if (ret == 0) {
            connected = true;
            break;
        }

        switch(errno) {
        case EINPROGRESS:
            pfd.fd = sd;
            pfd.events = POLLOUT;

            ret = poll(&pfd, 1, SSS_CLI_SOCKET_TIMEOUT - wait_time);

            if (ret > 0) {
                errnosize = sizeof(connect_errno);
                ret = getsockopt(sd, SOL_SOCKET, SO_ERROR,
                                 &connect_errno, &errnosize);
                if (ret >= 0 && connect_errno == 0) {
                    connected = true;
                    break;
                }
            }
            wait_time = time(NULL) - start_time;
            break;
        case EAGAIN:
            if (wait_time < SSS_CLI_SOCKET_TIMEOUT) {
                sleep_time = rand() % 2 + 1;
                sleep(sleep_time);
            }
            break;
        default:
            *errnop = errno;
            inprogress = false;
            break;
        }

        if (wait_time >= SSS_CLI_SOCKET_TIMEOUT) {
            inprogress = false;
        }

        if (connected) {
            inprogress = false;
        }
    }

    if (!connected) {
        close(sd);
        return -1;
    }

    ret = fstat(sd, &sss_cli_sb);
    if (ret != 0) {
        close(sd);
        return -1;
    }

    return sd;
}

static enum sss_status sss_cli_check_socket(int *errnop, const char *socket_name)
{
    static pid_t mypid;
    struct stat mysb;
    int mysd;
    int ret;

    if (getpid() != mypid) {
        ret = fstat(sss_cli_sd, &mysb);
        if (ret == 0) {
            if (S_ISSOCK(mysb.st_mode) &&
                mysb.st_dev == sss_cli_sb.st_dev &&
                mysb.st_ino == sss_cli_sb.st_ino) {
                sss_cli_close_socket();
            }
        }
        sss_cli_sd = -1;
        mypid = getpid();
    }

    /* check if the socket has been closed on the other side */
    if (sss_cli_sd != -1) {
        struct pollfd pfd;
        int res, error;

        *errnop = 0;
        pfd.fd = sss_cli_sd;
        pfd.events = POLLIN | POLLOUT;

        do {
            errno = 0;
            res = poll(&pfd, 1, SSS_CLI_SOCKET_TIMEOUT);
            error = errno;

            /* If error is EINTR here, we'll try again
             * If it's any other error, we'll catch it
             * below.
             */
        } while (error == EINTR);

        switch (res) {
        case -1:
            *errnop = error;
            break;
        case 0:
            *errnop = ETIME;
            break;
        case 1:
            if (pfd.revents & (POLLERR | POLLHUP | POLLNVAL)) {
                *errnop = EPIPE;
            }
            if (!(pfd.revents & (POLLIN | POLLOUT))) {
                *errnop = EBUSY;
            }
            break;
        default: /* more than one avail ?? */
            *errnop = EBADF;
            break;
        }
        if (*errnop == 0) {
            return SSS_STATUS_SUCCESS;
        }

        sss_cli_close_socket();
    }

    mysd = sss_cli_open_socket(errnop, socket_name);
    if (mysd == -1) {
        return SSS_STATUS_UNAVAIL;
    }

    sss_cli_sd = mysd;

    if (sss_cli_check_version(socket_name)) {
        return SSS_STATUS_SUCCESS;
    }

    sss_cli_close_socket();
    *errnop = EFAULT;
    return SSS_STATUS_UNAVAIL;
}

/* this function will check command codes match and returned length is ok */
/* repbuf and replen report only the data section not the header */
enum nss_status sss_nss_make_request(enum sss_cli_command cmd,
                      struct sss_cli_req_data *rd,
                      uint8_t **repbuf, size_t *replen,
                      int *errnop)
{
    enum sss_status ret;
    char *envval;

    /* avoid looping in the nss daemon */
    envval = getenv("_SSS_LOOPS");
    if (envval && strcmp(envval, "NO") == 0) {
        return NSS_STATUS_NOTFOUND;
    }

    ret = sss_cli_check_socket(errnop, SSS_NSS_SOCKET_NAME);
    if (ret != SSS_STATUS_SUCCESS) {
        return NSS_STATUS_UNAVAIL;
    }

    ret = sss_cli_make_request_nochecks(cmd, rd, repbuf, replen, errnop);
    switch (ret) {
    case SSS_STATUS_TRYAGAIN:
        return NSS_STATUS_TRYAGAIN;
    case SSS_STATUS_SUCCESS:
        return NSS_STATUS_SUCCESS;
    case SSS_STATUS_UNAVAIL:
    default:
        return NSS_STATUS_UNAVAIL;
    }
}

int sss_pac_make_request(enum sss_cli_command cmd,
                         struct sss_cli_req_data *rd,
                         uint8_t **repbuf, size_t *replen,
                         int *errnop)
{
    enum sss_status ret;
    char *envval;

    /* avoid looping in the nss daemon */
    envval = getenv("_SSS_LOOPS");
    if (envval && strcmp(envval, "NO") == 0) {
        return NSS_STATUS_NOTFOUND;
    }

    ret = sss_cli_check_socket(errnop, SSS_PAC_SOCKET_NAME);
    if (ret != SSS_STATUS_SUCCESS) {
        return NSS_STATUS_UNAVAIL;
    }

    ret = sss_cli_make_request_nochecks(cmd, rd, repbuf, replen, errnop);
    switch (ret) {
    case SSS_STATUS_TRYAGAIN:
        return NSS_STATUS_TRYAGAIN;
    case SSS_STATUS_SUCCESS:
        return NSS_STATUS_SUCCESS;
    case SSS_STATUS_UNAVAIL:
    default:
        return NSS_STATUS_UNAVAIL;
    }
}

errno_t check_server_cred(int sockfd)
{
#ifdef HAVE_UCRED
    int ret;
    struct ucred server_cred;
    socklen_t server_cred_len = sizeof(server_cred);

    ret = getsockopt(sockfd, SOL_SOCKET, SO_PEERCRED, &server_cred,
                     &server_cred_len);
    if (ret != 0) {
        return errno;
    }

    if (server_cred_len != sizeof(struct ucred)) {
        return ESSS_BAD_CRED_MSG;
    }

    if (server_cred.uid != 0 || server_cred.gid != 0) {
        return ESSS_SERVER_NOT_TRUSTED;
    }
#endif
    return 0;
}
int sss_pam_make_request(enum sss_cli_command cmd,
                      struct sss_cli_req_data *rd,
                      uint8_t **repbuf, size_t *replen,
                      int *errnop)
{
    int ret, statret;
    errno_t error;
    enum sss_status status;
    char *envval;
    struct stat stat_buf;

    sss_pam_lock();

    /* avoid looping in the pam daemon */
    envval = getenv("_SSS_LOOPS");
    if (envval && strcmp(envval, "NO") == 0) {
        ret = PAM_SERVICE_ERR;
        goto out;
    }

    /* only root shall use the privileged pipe */
    if (getuid() == 0 && getgid() == 0) {
        statret = stat(SSS_PAM_PRIV_SOCKET_NAME, &stat_buf);
        if (statret != 0) {
            ret = PAM_SERVICE_ERR;
            goto out;
        }
        if ( ! (stat_buf.st_uid == 0 &&
                stat_buf.st_gid == 0 &&
                S_ISSOCK(stat_buf.st_mode) &&
                (stat_buf.st_mode & ~S_IFMT) == 0600 )) {
            *errnop = ESSS_BAD_PRIV_SOCKET;
            ret = PAM_SERVICE_ERR;
            goto out;
        }

        status = sss_cli_check_socket(errnop, SSS_PAM_PRIV_SOCKET_NAME);
    } else {
        statret = stat(SSS_PAM_SOCKET_NAME, &stat_buf);
        if (statret != 0) {
            ret = PAM_SERVICE_ERR;
            goto out;
        }
        if ( ! (stat_buf.st_uid == 0 &&
                stat_buf.st_gid == 0 &&
                S_ISSOCK(stat_buf.st_mode) &&
                (stat_buf.st_mode & ~S_IFMT) == 0666 )) {
            *errnop = ESSS_BAD_PUB_SOCKET;
            ret = PAM_SERVICE_ERR;
            goto out;
        }

        status = sss_cli_check_socket(errnop, SSS_PAM_SOCKET_NAME);
    }
    if (status != SSS_STATUS_SUCCESS) {
        ret = PAM_SERVICE_ERR;
        goto out;
    }

    error = check_server_cred(sss_cli_sd);
    if (error != 0) {
        sss_cli_close_socket();
        *errnop = error;
        ret = PAM_SERVICE_ERR;
        goto out;
    }

    status = sss_cli_make_request_nochecks(cmd, rd, repbuf, replen, errnop);
    if (status == SSS_STATUS_SUCCESS) {
        ret = PAM_SUCCESS;
    } else {
        ret = PAM_SERVICE_ERR;
    }

out:
    sss_pam_unlock();
    return ret;
}

int sss_sudo_make_request(enum sss_cli_command cmd,
                          struct sss_cli_req_data *rd,
                          uint8_t **repbuf, size_t *replen,
                          int *errnop)
{
    enum sss_status ret = SSS_STATUS_UNAVAIL;

    ret = sss_cli_check_socket(errnop, SSS_SUDO_SOCKET_NAME);
    if (ret != SSS_STATUS_SUCCESS) {
        return SSS_STATUS_UNAVAIL;
    }

    ret = sss_cli_make_request_nochecks(cmd, rd, repbuf, replen, errnop);

    return ret;
}

int sss_autofs_make_request(enum sss_cli_command cmd,
                            struct sss_cli_req_data *rd,
                            uint8_t **repbuf, size_t *replen,
                            int *errnop)
{
    enum sss_status ret = SSS_STATUS_UNAVAIL;

    ret = sss_cli_check_socket(errnop, SSS_AUTOFS_SOCKET_NAME);
    if (ret != SSS_STATUS_SUCCESS) {
        return SSS_STATUS_UNAVAIL;
    }

    ret = sss_cli_make_request_nochecks(cmd, rd, repbuf, replen, errnop);

    return ret;
}

int sss_ssh_make_request(enum sss_cli_command cmd,
                         struct sss_cli_req_data *rd,
                         uint8_t **repbuf, size_t *replen,
                         int *errnop)
{
    enum sss_status ret = SSS_STATUS_UNAVAIL;

    ret = sss_cli_check_socket(errnop, SSS_SSH_SOCKET_NAME);
    if (ret != SSS_STATUS_SUCCESS) {
        return SSS_STATUS_UNAVAIL;
    }

    ret = sss_cli_make_request_nochecks(cmd, rd, repbuf, replen, errnop);

    return ret;
}


const char *ssscli_err2string(int err)
{
    const char *m;

    switch(err) {
        case ESSS_BAD_PRIV_SOCKET:
            return _("Privileged socket has wrong ownership or permissions.");
            break;
        case ESSS_BAD_PUB_SOCKET:
            return _("Public socket has wrong ownership or permissions.");
            break;
        case ESSS_BAD_CRED_MSG:
            return _("Unexpected format of the server credential message.");
            break;
        case ESSS_SERVER_NOT_TRUSTED:
            return _("SSSD is not run by root.");
            break;
        default:
            m = strerror(err);
            if (m == NULL) {
                return _("An error occurred, but no description can be found.");
            }
            return m;
            break;
    }

    return _("Unexpected error while looking for an error description");
}

/* Return strlen(str) or maxlen, whichever is shorter
 * Returns EINVAL if str is NULL, EFBIG if str is longer than maxlen
 * _len will return the result
 *
 * This function is useful for preventing buffer overflow attacks.
 */
errno_t sss_strnlen(const char *str, size_t maxlen, size_t *len)
{
    if (!str) {
        return EINVAL;
    }

#if defined __USE_GNU
    *len = strnlen(str, maxlen);
#else
    *len = 0;
    while (*len < maxlen) {
        if (str[*len] == '\0') break;
        len++;
    }
#endif

    if (*len == maxlen && str[*len] != '\0') {
        return EFBIG;
    }

    return 0;
}

#if HAVE_PTHREAD
static pthread_mutex_t sss_nss_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t sss_pam_mutex = PTHREAD_MUTEX_INITIALIZER;

void sss_nss_lock(void)
{
    pthread_mutex_lock(&sss_nss_mutex);
}
void sss_nss_unlock(void)
{
    pthread_mutex_unlock(&sss_nss_mutex);
}
void sss_pam_lock(void)
{
    pthread_mutex_lock(&sss_pam_mutex);
}
void sss_pam_unlock(void)
{
    pthread_mutex_unlock(&sss_pam_mutex);
}

#else

/* sorry no mutexes available */
void sss_nss_lock(void) { return; }
void sss_nss_unlock(void) { return; }
void sss_pam_lock(void) { return; }
void sss_pam_unlock(void) { return; }
#endif


errno_t sss_readrep_copy_string(const char *in,
                                size_t *offset,
                                size_t *slen,
                                size_t *dlen,
                                char **out,
                                size_t *size)
{
    size_t i = 0;
    while (*slen > *offset && *dlen > 0) {
        (*out)[i] = in[*offset];
        if ((*out)[i] == '\0') break;
        i++;
        (*offset)++;
        (*dlen)--;
    }
    if (*slen <= *offset) { /* premature end of buf */
        return EBADMSG;
    }
    if (*dlen == 0) { /* not enough memory */
        return ERANGE; /* not ENOMEM, ERANGE is what glibc looks for */
    }
    (*offset)++;
    (*dlen)--;
    if (size) {
        *size = i;
    }

    return EOK;
}