1
/* -*- coding: utf-8; mode: c; mode: orgtbl -*- */
1
/* -*- coding: utf-8 -*- */
3
3
* Mandos plugin runner - Run Mandos plugins
5
* Copyright © 2008-2017 Teddy Hogeborn
6
* Copyright © 2008-2017 Björn Påhlsson
8
* This file is part of Mandos.
10
* Mandos is free software: you can redistribute it and/or modify it
11
* under the terms of the GNU General Public License as published by
12
* the Free Software Foundation, either version 3 of the License, or
13
* (at your option) any later version.
15
* Mandos is distributed in the hope that it will be useful, but
5
* Copyright © 2008,2009 Teddy Hogeborn
6
* Copyright © 2008,2009 Björn Påhlsson
8
* This program is free software: you can redistribute it and/or
9
* modify it under the terms of the GNU General Public License as
10
* published by the Free Software Foundation, either version 3 of the
11
* License, or (at your option) any later version.
13
* This program is distributed in the hope that it will be useful, but
16
14
* WITHOUT ANY WARRANTY; without even the implied warranty of
17
15
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18
16
* General Public License for more details.
20
18
* You should have received a copy of the GNU General Public License
21
* along with Mandos. If not, see <http://www.gnu.org/licenses/>.
19
* along with this program. If not, see
20
* <http://www.gnu.org/licenses/>.
23
* Contact the authors at <mandos@recompile.se>.
22
* Contact the authors at <mandos@fukt.bsnet.se>.
26
25
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
28
27
#include <stddef.h> /* size_t, NULL */
29
#include <stdlib.h> /* malloc(), exit(), EXIT_SUCCESS,
28
#include <stdlib.h> /* malloc(), exit(), EXIT_FAILURE,
29
EXIT_SUCCESS, realloc() */
31
30
#include <stdbool.h> /* bool, true, false */
32
#include <stdio.h> /* fileno(), fprintf(),
33
stderr, STDOUT_FILENO, fclose() */
34
#include <sys/types.h> /* fstat(), struct stat, waitpid(),
35
WIFEXITED(), WEXITSTATUS(), wait(),
36
pid_t, uid_t, gid_t, getuid(),
31
#include <stdio.h> /* perror, fileno(), fprintf(),
32
stderr, STDOUT_FILENO */
33
#include <sys/types.h> /* DIR, opendir(), stat(), struct
34
stat, waitpid(), WIFEXITED(),
35
WEXITSTATUS(), wait(), pid_t,
36
uid_t, gid_t, getuid(), getgid(),
38
38
#include <sys/select.h> /* fd_set, select(), FD_ZERO(),
39
39
FD_SET(), FD_ISSET(), FD_CLR */
40
40
#include <sys/wait.h> /* wait(), waitpid(), WIFEXITED(),
41
WEXITSTATUS(), WTERMSIG() */
42
#include <sys/stat.h> /* struct stat, fstat(), S_ISREG() */
41
WEXITSTATUS(), WTERMSIG(),
43
#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
43
44
#include <iso646.h> /* and, or, not */
44
#include <dirent.h> /* struct dirent, scandirat() */
45
#include <unistd.h> /* fcntl(), F_GETFD, F_SETFD,
46
FD_CLOEXEC, write(), STDOUT_FILENO,
47
struct stat, fstat(), close(),
48
setgid(), setuid(), S_ISREG(),
49
faccessat() pipe2(), fork(),
50
_exit(), dup2(), fexecve(), read()
45
#include <dirent.h> /* DIR, struct dirent, opendir(),
46
readdir(), closedir(), dirfd() */
47
#include <unistd.h> /* struct stat, stat(), S_ISREG(),
48
fcntl(), setuid(), setgid(),
49
F_GETFD, F_SETFD, FD_CLOEXEC,
50
access(), pipe(), fork(), close()
51
dup2(), STDOUT_FILENO, _exit(),
52
execv(), write(), read(),
52
54
#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
53
FD_CLOEXEC, openat(), scandirat(),
55
#include <string.h> /* strsep, strlen(), strsignal(),
56
strcmp(), strncmp() */
56
#include <string.h> /* strsep, strlen(), asprintf(),
57
58
#include <errno.h> /* errno */
58
59
#include <argp.h> /* struct argp_option, struct
59
60
argp_state, struct argp,
417
377
.doc = "Group ID the plugins will run as", .group = 3 },
418
378
{ .name = "debug", .key = 132,
419
379
.doc = "Debug mode", .group = 4 },
420
{ .name = "plugin-helper-dir", .key = 133,
422
.doc = "Specify a different plugin helper directory",
425
* These reproduce what we would get without ARGP_NO_HELP
427
{ .name = "help", .key = '?',
428
.doc = "Give this help list", .group = -1 },
429
{ .name = "usage", .key = -3,
430
.doc = "Give a short usage message", .group = -1 },
431
{ .name = "version", .key = 'V',
432
.doc = "Print program version", .group = -1 },
436
__attribute__((nonnull(3)))
437
error_t parse_opt(int key, char *arg, struct argp_state *state){
383
error_t parse_opt(int key, char *arg, __attribute__((unused))
384
struct argp_state *state){
442
387
case 'g': /* --global-options */
444
389
char *plugin_option;
445
390
while((plugin_option = strsep(&arg, ",")) != NULL){
391
if(plugin_option[0] == '\0'){
446
394
if(not add_argument(getplugin(NULL), plugin_option)){
395
perror("add_argument");
396
return ARGP_ERR_UNKNOWN;
453
401
case 'G': /* --global-env */
454
if(add_environment(getplugin(NULL), arg, true)){
405
if(not add_environment(getplugin(NULL), arg, true)){
406
perror("add_environment");
458
409
case 'o': /* --options-for */
460
char *option_list = strchr(arg, ':');
461
if(option_list == NULL){
462
argp_error(state, "No colon in \"%s\"", arg);
469
argp_error(state, "Empty plugin name");
474
while((option = strsep(&option_list, ",")) != NULL){
475
if(not add_argument(getplugin(arg), option)){
411
char *plugin_name = strsep(&arg, ":");
412
if(plugin_name[0] == '\0'){
416
while((plugin_option = strsep(&arg, ",")) != NULL){
417
if(not add_argument(getplugin(plugin_name), plugin_option)){
418
perror("add_argument");
419
return ARGP_ERR_UNKNOWN;
482
424
case 'E': /* --env-for */
484
429
char *envdef = strchr(arg, ':');
485
430
if(envdef == NULL){
486
argp_error(state, "No colon in \"%s\"", arg);
493
argp_error(state, "Empty plugin name");
497
if(add_environment(getplugin(arg), envdef, true)){
434
if(not add_environment(getplugin(arg), envdef+1, true)){
435
perror("add_environment");
502
439
case 'd': /* --disable */
504
441
plugin *p = getplugin(arg);
443
return ARGP_ERR_UNKNOWN;
511
448
case 'e': /* --enable */
513
450
plugin *p = getplugin(arg);
452
return ARGP_ERR_UNKNOWN;
520
457
case 128: /* --plugin-dir */
522
459
plugindir = strdup(arg);
523
if(plugindir != NULL){
460
if(plugindir == NULL){
527
464
case 129: /* --config-file */
528
465
/* This is already done by parse_opt_config_file() */
530
467
case 130: /* --userid */
531
tmp_id = strtoimax(arg, &tmp, 10);
469
tmpmax = strtoimax(arg, &tmp, 10);
532
470
if(errno != 0 or tmp == arg or *tmp != '\0'
533
or tmp_id != (uid_t)tmp_id){
534
argp_error(state, "Bad user ID number: \"%s\", using %"
535
PRIdMAX, arg, (intmax_t)uid);
471
or tmpmax != (uid_t)tmpmax){
472
fprintf(stderr, "Bad user ID number: \"%s\", using %"
473
PRIdMAX "\n", arg, (intmax_t)uid);
541
478
case 131: /* --groupid */
542
tmp_id = strtoimax(arg, &tmp, 10);
480
tmpmax = strtoimax(arg, &tmp, 10);
543
481
if(errno != 0 or tmp == arg or *tmp != '\0'
544
or tmp_id != (gid_t)tmp_id){
545
argp_error(state, "Bad group ID number: \"%s\", using %"
546
PRIdMAX, arg, (intmax_t)gid);
482
or tmpmax != (gid_t)tmpmax){
483
fprintf(stderr, "Bad group ID number: \"%s\", using %"
484
PRIdMAX "\n", arg, (intmax_t)gid);
552
489
case 132: /* --debug */
555
case 133: /* --plugin-helper-dir */
556
free(pluginhelperdir);
557
pluginhelperdir = strdup(arg);
558
if(pluginhelperdir != NULL){
563
* These reproduce what we would get without ARGP_NO_HELP
565
case '?': /* --help */
566
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
567
argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
568
case -3: /* --usage */
569
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
570
argp_state_help(state, state->out_stream,
571
ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
572
case 'V': /* --version */
573
fprintf(state->out_stream, "%s\n", argp_program_version);
577
493
* When adding more options before this line, remember to also add a
578
494
* "case" to the "parse_opt_config_file" function below.
694
599
new_arg = strdup(p);
695
600
if(new_arg == NULL){
696
error(0, errno, "strdup");
697
exitstatus = EX_OSERR;
602
exitstatus = EXIT_FAILURE;
702
607
custom_argc += 1;
704
char **new_argv = realloc(custom_argv, sizeof(char *)
705
* ((size_t)custom_argc + 1));
706
if(new_argv == NULL){
707
error(0, errno, "realloc");
708
exitstatus = EX_OSERR;
713
custom_argv = new_argv;
608
custom_argv = realloc(custom_argv, sizeof(char *)
609
* ((unsigned int) custom_argc + 1));
610
if(custom_argv == NULL){
612
exitstatus = EXIT_FAILURE;
716
616
custom_argv[custom_argc-1] = new_arg;
717
617
custom_argv[custom_argc] = NULL;
721
ret = fclose(conffp);
722
} while(ret == EOF and errno == EINTR);
724
error(0, errno, "fclose");
725
exitstatus = EX_IOERR;
730
622
/* Check for harmful errors and go to fallback. Other errors might
731
623
not affect opening plugins */
732
624
if(errno == EMFILE or errno == ENFILE or errno == ENOMEM){
733
error(0, errno, "fopen");
734
exitstatus = EX_OSERR;
626
exitstatus = EXIT_FAILURE;
738
/* If there were any arguments from the configuration file, pass
739
them to parser as command line arguments */
630
/* If there was any arguments from configuration file,
631
pass them to parser as command arguments */
740
632
if(custom_argv != NULL){
741
ret = argp_parse(&argp, custom_argc, custom_argv,
742
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
750
error(0, errno, "argp_parse");
751
exitstatus = EX_OSERR;
754
exitstatus = EX_CONFIG;
633
ret = argp_parse(&argp, custom_argc, custom_argv, ARGP_IN_ORDER,
635
if(ret == ARGP_ERR_UNKNOWN){
636
fprintf(stderr, "Unknown error while parsing arguments\n");
637
exitstatus = EXIT_FAILURE;
759
642
/* Parse actual command line arguments, to let them override the
761
ret = argp_parse(&argp, argc, argv,
762
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
770
error(0, errno, "argp_parse");
771
exitstatus = EX_OSERR;
774
exitstatus = EX_USAGE;
779
char *pluginhelperenv;
781
ret = asprintf(&pluginhelperenv, "MANDOSPLUGINHELPERDIR=%s",
782
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
784
bret = add_environment(getplugin(NULL), pluginhelperenv, true);
786
if(ret == -1 or not bret){
787
error(0, errno, "Failed to set MANDOSPLUGINHELPERDIR"
788
" environment variable to \"%s\" for all plugins\n",
789
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
792
free(pluginhelperenv);
644
ret = argp_parse(&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
645
if(ret == ARGP_ERR_UNKNOWN){
646
fprintf(stderr, "Unknown error while parsing arguments\n");
647
exitstatus = EXIT_FAILURE;
797
for(plugin *p = plugin_list; p != NULL; p = p->next){
652
for(plugin *p = plugin_list; p != NULL; p=p->next){
798
653
fprintf(stderr, "Plugin: %s has %d arguments\n",
799
654
p->name ? p->name : "Global", p->argc - 1);
800
655
for(char **a = p->argv; *a != NULL; a++){
811
/* Work around Debian bug #633582:
812
<https://bugs.debian.org/633582> */
813
int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
814
if(plugindir_fd == -1){
816
error(0, errno, "open(\"" PDIR "\")");
819
ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
821
error(0, errno, "fstat");
823
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
824
ret = fchown(plugindir_fd, uid, gid);
826
error(0, errno, "fchown");
834
/* Lower permissions */
665
/* Strip permissions down to nobody */
837
error(0, errno, "setgid");
839
670
ret = setuid(uid);
841
error(0, errno, "setuid");
844
/* Open plugin directory with close_on_exec flag */
675
if(plugindir == NULL){
678
dir = opendir(plugindir);
682
perror("Could not open plugin dir");
683
exitstatus = EXIT_FAILURE;
687
/* Set the FD_CLOEXEC flag on the directory, if possible */
846
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
849
#else /* not O_CLOEXEC */
851
#endif /* not O_CLOEXEC */
854
error(0, errno, "Could not open plugin dir");
855
exitstatus = EX_UNAVAILABLE;
860
/* Set the FD_CLOEXEC flag on the directory */
861
ret = set_cloexec_flag(dir_fd);
863
error(0, errno, "set_cloexec_flag");
864
exitstatus = EX_OSERR;
867
#endif /* O_CLOEXEC */
870
int good_name(const struct dirent * const dirent){
871
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
872
"*.dpkg-old", "*.dpkg-bak",
873
"*.dpkg-divert", NULL };
875
#pragma GCC diagnostic push
876
#pragma GCC diagnostic ignored "-Wcast-qual"
878
for(const char **pat = (const char **)patterns;
879
*pat != NULL; pat++){
881
#pragma GCC diagnostic pop
883
if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
886
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
887
" matching pattern %s\n", dirent->d_name, *pat);
689
int dir_fd = dirfd(dir);
691
ret = set_cloexec_flag(dir_fd);
693
perror("set_cloexec_flag");
694
exitstatus = EXIT_FAILURE;
895
int numplugins = scandirat(dir_fd, ".", &direntries, good_name,
897
if(numplugins == -1){
898
error(0, errno, "Could not scan plugin dir");
900
exitstatus = EX_OSERR;
904
700
FD_ZERO(&rfds_all);
906
702
/* Read and execute any executable in the plugin directory*/
907
for(int i = 0; i < numplugins; i++){
909
int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
911
error(0, errno, "Could not open plugin");
704
dirst = readdir(dir);
706
/* All directory entries have been processed */
710
exitstatus = EXIT_FAILURE;
716
d_name_len = strlen(dirst->d_name);
718
/* Ignore dotfiles, backup files and other junk */
720
bool bad_name = false;
722
const char const *bad_prefixes[] = { ".", "#", NULL };
724
const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
727
".dpkg-divert", NULL };
728
for(const char **pre = bad_prefixes; *pre != NULL; pre++){
729
size_t pre_len = strlen(*pre);
730
if((d_name_len >= pre_len)
731
and strncmp((dirst->d_name), *pre, pre_len) == 0){
733
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
734
" with bad prefix %s\n", dirst->d_name, *pre);
743
for(const char **suf = bad_suffixes; *suf != NULL; suf++){
744
size_t suf_len = strlen(*suf);
745
if((d_name_len >= suf_len)
746
and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
749
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
750
" with bad suffix %s\n", dirst->d_name, *suf);
763
if(plugindir == NULL){
764
ret = asprintf(&filename, PDIR "/%s", dirst->d_name);
766
ret = asprintf(&filename, "%s/%s", plugindir, dirst->d_name);
915
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
773
ret = stat(filename, &st);
917
error(0, errno, "stat");
923
780
/* Ignore non-executable files */
924
if(not S_ISREG(st.st_mode)
925
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
781
if(not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){
928
fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
929
" with bad type or mode\n",
930
plugindir != NULL ? plugindir : PDIR,
931
direntries[i]->d_name);
783
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
784
" with bad type or mode\n", filename);
938
plugin *p = getplugin(direntries[i]->d_name);
790
plugin *p = getplugin(dirst->d_name);
940
error(0, errno, "getplugin");
947
798
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
948
direntries[i]->d_name);
958
808
for(char **a = g->argv + 1; *a != NULL; a++){
959
809
if(not add_argument(p, *a)){
960
error(0, errno, "add_argument");
810
perror("add_argument");
963
813
/* Add global environment variables */
964
814
for(char **e = g->environ; *e != NULL; e++){
965
815
if(not add_environment(p, *e, false)){
966
error(0, errno, "add_environment");
816
perror("add_environment");
971
/* If this plugin has any environment variables, we need to
972
duplicate the environment from this process, too. */
821
/* If this plugin has any environment variables, we will call
822
using execve and need to duplicate the environment from this
973
824
if(p->environ[0] != NULL){
974
825
for(char **e = environ; *e != NULL; e++){
975
826
if(not add_environment(p, *e, false)){
976
error(0, errno, "add_environment");
827
perror("add_environment");
983
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
984
#else /* O_CLOEXEC */
985
ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
986
#endif /* O_CLOEXEC */
988
error(0, errno, "pipe");
989
exitstatus = EX_OSERR;
993
if(pipefd[0] >= FD_SETSIZE){
994
fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
998
exitstatus = EX_OSERR;
836
exitstatus = EXIT_FAILURE;
1003
839
/* Ask OS to automatic close the pipe on exec */
1004
840
ret = set_cloexec_flag(pipefd[0]);
1006
error(0, errno, "set_cloexec_flag");
1009
exitstatus = EX_OSERR;
1010
free(direntries[i]);
842
perror("set_cloexec_flag");
843
exitstatus = EXIT_FAILURE;
1013
846
ret = set_cloexec_flag(pipefd[1]);
1015
error(0, errno, "set_cloexec_flag");
1018
exitstatus = EX_OSERR;
1019
free(direntries[i]);
848
perror("set_cloexec_flag");
849
exitstatus = EXIT_FAILURE;
1022
#endif /* not O_CLOEXEC */
1023
852
/* Block SIGCHLD until process is safely in process list */
1024
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
1025
&sigchld_action.sa_mask,
853
ret = sigprocmask(SIG_BLOCK, &sigchld_action.sa_mask, NULL);
1028
error(0, errno, "sigprocmask");
1029
exitstatus = EX_OSERR;
1030
free(direntries[i]);
855
perror("sigprocmask");
856
exitstatus = EXIT_FAILURE;
1033
859
/* Starting a new process to be watched */
1037
} while(pid == -1 and errno == EINTR);
1039
error(0, errno, "fork");
1040
TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1041
&sigchld_action.sa_mask, NULL));
1044
exitstatus = EX_OSERR;
1045
free(direntries[i]);
863
exitstatus = EXIT_FAILURE;
1049
867
/* this is the child process */
1050
868
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1052
error(0, errno, "sigaction");
1055
873
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1057
error(0, errno, "sigprocmask");
875
perror("sigprocmask");
1061
879
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1063
error(0, errno, "dup2");
1067
if(fexecve(plugin_fd, p->argv,
1068
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1069
error(0, errno, "fexecve for %s/%s",
1070
plugindir != NULL ? plugindir : PDIR,
1071
direntries[i]->d_name);
886
/* If dir has no file descriptor, we could not set FD_CLOEXEC
887
above and must now close it manually here. */
890
if(p->environ[0] == NULL){
891
if(execv(filename, p->argv) < 0){
896
if(execve(filename, p->argv, p->environ) < 0){
1076
903
/* Parent process */
1077
904
close(pipefd[1]); /* Close unused write end of pipe */
1079
plugin *new_plugin = getplugin(direntries[i]->d_name);
906
plugin *new_plugin = getplugin(dirst->d_name);
1080
907
if(new_plugin == NULL){
1081
error(0, errno, "getplugin");
1082
ret = (int)(TEMP_FAILURE_RETRY
1083
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
909
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1086
error(0, errno, "sigprocmask");
911
perror("sigprocmask");
1088
exitstatus = EX_OSERR;
1089
free(direntries[i]);
913
exitstatus = EXIT_FAILURE;
1092
free(direntries[i]);
1094
917
new_plugin->pid = pid;
1095
918
new_plugin->fd = pipefd[0];
1097
920
/* Unblock SIGCHLD so signal handler can be run if this process
1098
921
has already completed */
1099
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1100
&sigchld_action.sa_mask,
922
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1103
error(0, errno, "sigprocmask");
1104
exitstatus = EX_OSERR;
924
perror("sigprocmask");
925
exitstatus = EXIT_FAILURE;