3
3
* Mandos plugin runner - Run Mandos plugins
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
5
* Copyright © 2008-2020 Teddy Hogeborn
6
* Copyright © 2008-2020 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
14
16
* WITHOUT ANY WARRANTY; without even the implied warranty of
15
17
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16
18
* General Public License for more details.
18
20
* You should have received a copy of the GNU General Public License
19
* along with this program. If not, see
20
* <http://www.gnu.org/licenses/>.
21
* along with Mandos. If not, see <http://www.gnu.org/licenses/>.
22
* Contact the authors at <mandos@fukt.bsnet.se>.
23
* Contact the authors at <mandos@recompile.se>.
25
26
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
27
28
#include <stddef.h> /* size_t, NULL */
28
#include <stdlib.h> /* malloc(), exit(), EXIT_FAILURE,
29
EXIT_SUCCESS, realloc() */
29
#include <stdlib.h> /* malloc(), reallocarray(), realloc(),
30
EXIT_SUCCESS, exit() */
30
31
#include <stdbool.h> /* bool, true, false */
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(),
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(),
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(),
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WEXITSTATUS(), WTERMSIG(),
43
#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
41
WEXITSTATUS(), WTERMSIG() */
42
#include <sys/stat.h> /* struct stat, fstat(), S_ISREG() */
44
43
#include <iso646.h> /* and, or, not */
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(),
44
#include <dirent.h> /* struct dirent, scandirat() */
45
#include <unistd.h> /* fcntl(), F_GETFD, F_SETFD,
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FD_CLOEXEC, write(), STDOUT_FILENO,
47
struct stat, fstat(), close(),
48
setgid(), setuid(), S_ISREG(),
49
faccessat() pipe2(), fork(),
50
_exit(), dup2(), fexecve(), read(),
54
52
#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
56
#include <string.h> /* strsep, strlen(), asprintf(),
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FD_CLOEXEC, openat(), scandirat(),
55
#include <string.h> /* strsep, strlen(), strsignal(),
56
strcmp(), strncmp() */
58
57
#include <errno.h> /* errno */
59
58
#include <argp.h> /* struct argp_option, struct
60
59
argp_state, struct argp,
394
428
.doc = "Group ID the plugins will run as", .group = 3 },
395
429
{ .name = "debug", .key = 132,
396
430
.doc = "Debug mode", .group = 4 },
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{ .name = "plugin-helper-dir", .key = 133,
433
.doc = "Specify a different plugin helper directory",
436
* These reproduce what we would get without ARGP_NO_HELP
438
{ .name = "help", .key = '?',
439
.doc = "Give this help list", .group = -1 },
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{ .name = "usage", .key = -3,
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.doc = "Give a short usage message", .group = -1 },
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{ .name = "version", .key = 'V',
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.doc = "Print program version", .group = -1 },
400
error_t parse_opt(int key, char *arg, __attribute__((unused))
401
struct argp_state *state){
447
__attribute__((nonnull(3)))
448
error_t parse_opt(int key, char *arg, struct argp_state *state){
405
453
case 'g': /* --global-options */
407
455
char *plugin_option;
408
456
while((plugin_option = strsep(&arg, ",")) != NULL){
409
if(plugin_option[0] == '\0'){
412
457
if(not add_argument(getplugin(NULL), plugin_option)){
413
perror("add_argument");
414
return ARGP_ERR_UNKNOWN;
419
464
case 'G': /* --global-env */
423
if(not add_environment(getplugin(NULL), arg, true)){
424
perror("add_environment");
465
if(add_environment(getplugin(NULL), arg, true)){
427
469
case 'o': /* --options-for */
429
char *plugin_name = strsep(&arg, ":");
430
if(plugin_name[0] == '\0'){
434
while((plugin_option = strsep(&arg, ",")) != NULL){
435
if(not add_argument(getplugin(plugin_name), plugin_option)){
436
perror("add_argument");
437
return ARGP_ERR_UNKNOWN;
471
char *option_list = strchr(arg, ':');
472
if(option_list == NULL){
473
argp_error(state, "No colon in \"%s\"", arg);
480
argp_error(state, "Empty plugin name");
485
while((option = strsep(&option_list, ",")) != NULL){
486
if(not add_argument(getplugin(arg), option)){
442
493
case 'E': /* --env-for */
447
495
char *envdef = strchr(arg, ':');
448
496
if(envdef == NULL){
497
argp_error(state, "No colon in \"%s\"", arg);
452
if(not add_environment(getplugin(arg), envdef+1, true)){
453
perror("add_environment");
504
argp_error(state, "Empty plugin name");
508
if(add_environment(getplugin(arg), envdef, true)){
457
513
case 'd': /* --disable */
459
515
plugin *p = getplugin(arg);
461
return ARGP_ERR_UNKNOWN;
466
522
case 'e': /* --enable */
468
524
plugin *p = getplugin(arg);
470
return ARGP_ERR_UNKNOWN;
475
531
case 128: /* --plugin-dir */
477
533
plugindir = strdup(arg);
478
if(plugindir == NULL){
534
if(plugindir != NULL){
482
538
case 129: /* --config-file */
483
539
/* This is already done by parse_opt_config_file() */
485
541
case 130: /* --userid */
487
tmpmax = strtoimax(arg, &tmp, 10);
542
tmp_id = strtoimax(arg, &tmp, 10);
488
543
if(errno != 0 or tmp == arg or *tmp != '\0'
489
or tmpmax != (uid_t)tmpmax){
490
fprintf(stderr, "Bad user ID number: \"%s\", using %"
491
PRIdMAX "\n", arg, (intmax_t)uid);
544
or tmp_id != (uid_t)tmp_id){
545
argp_error(state, "Bad user ID number: \"%s\", using %"
546
PRIdMAX, arg, (intmax_t)uid);
496
552
case 131: /* --groupid */
498
tmpmax = strtoimax(arg, &tmp, 10);
553
tmp_id = strtoimax(arg, &tmp, 10);
499
554
if(errno != 0 or tmp == arg or *tmp != '\0'
500
or tmpmax != (gid_t)tmpmax){
501
fprintf(stderr, "Bad group ID number: \"%s\", using %"
502
PRIdMAX "\n", arg, (intmax_t)gid);
555
or tmp_id != (gid_t)tmp_id){
556
argp_error(state, "Bad group ID number: \"%s\", using %"
557
PRIdMAX, arg, (intmax_t)gid);
507
563
case 132: /* --debug */
566
case 133: /* --plugin-helper-dir */
567
free(pluginhelperdir);
568
pluginhelperdir = strdup(arg);
569
if(pluginhelperdir != NULL){
574
* These reproduce what we would get without ARGP_NO_HELP
576
case '?': /* --help */
577
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
578
argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
579
__builtin_unreachable();
580
case -3: /* --usage */
581
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
582
argp_state_help(state, state->out_stream,
583
ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
584
__builtin_unreachable();
585
case 'V': /* --version */
586
fprintf(state->out_stream, "%s\n", argp_program_version);
511
590
* When adding more options before this line, remember to also add a
512
591
* "case" to the "parse_opt_config_file" function below.
648
759
/* Check for harmful errors and go to fallback. Other errors might
649
760
not affect opening plugins */
650
761
if(errno == EMFILE or errno == ENFILE or errno == ENOMEM){
652
exitstatus = EXIT_FAILURE;
762
error(0, errno, "fopen");
763
exitstatus = EX_OSERR;
656
/* If there was any arguments from configuration file,
657
pass them to parser as command arguments */
767
/* If there were any arguments from the configuration file, pass
768
them to parser as command line arguments */
658
769
if(custom_argv != NULL){
659
ret = argp_parse(&argp, custom_argc, custom_argv, ARGP_IN_ORDER,
661
if(ret == ARGP_ERR_UNKNOWN){
662
fprintf(stderr, "Unknown error while parsing arguments\n");
663
exitstatus = EXIT_FAILURE;
770
ret = argp_parse(&argp, custom_argc, custom_argv,
771
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
779
error(0, errno, "argp_parse");
780
exitstatus = EX_OSERR;
783
exitstatus = EX_CONFIG;
668
788
/* Parse actual command line arguments, to let them override the
670
ret = argp_parse(&argp, argc, argv, ARGP_IN_ORDER, 0, NULL);
671
if(ret == ARGP_ERR_UNKNOWN){
672
fprintf(stderr, "Unknown error while parsing arguments\n");
673
exitstatus = EXIT_FAILURE;
790
ret = argp_parse(&argp, argc, argv,
791
ARGP_IN_ORDER | ARGP_NO_EXIT | ARGP_NO_HELP,
799
error(0, errno, "argp_parse");
800
exitstatus = EX_OSERR;
803
exitstatus = EX_USAGE;
808
char *pluginhelperenv;
810
ret = asprintf(&pluginhelperenv, "MANDOSPLUGINHELPERDIR=%s",
811
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
813
bret = add_environment(getplugin(NULL), pluginhelperenv, true);
815
if(ret == -1 or not bret){
816
error(0, errno, "Failed to set MANDOSPLUGINHELPERDIR"
817
" environment variable to \"%s\" for all plugins\n",
818
pluginhelperdir != NULL ? pluginhelperdir : PHDIR);
821
free(pluginhelperenv);
678
for(plugin *p = plugin_list; p != NULL; p=p->next){
826
for(plugin *p = plugin_list; p != NULL; p = p->next){
679
827
fprintf(stderr, "Plugin: %s has %d arguments\n",
680
828
p->name ? p->name : "Global", p->argc - 1);
681
829
for(char **a = p->argv; *a != NULL; a++){
691
/* Strip permissions down to nobody */
840
/* Work around Debian bug #633582:
841
<https://bugs.debian.org/633582> */
842
int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
843
if(plugindir_fd == -1){
845
error(0, errno, "open(\"" PDIR "\")");
848
ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
850
error(0, errno, "fstat");
852
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
853
ret = fchown(plugindir_fd, uid, gid);
855
error(0, errno, "fchown");
862
/* Work around Debian bug #981302
863
<https://bugs.debian.org/981302> */
864
if(lstat("/dev/fd", &st) != 0 and errno == ENOENT){
865
ret = symlink("/proc/self/fd", "/dev/fd");
867
error(0, errno, "Failed to create /dev/fd symlink");
872
/* Lower permissions */
875
error(0, errno, "setgid");
696
877
ret = setuid(uid);
701
if(plugindir == NULL){
704
dir = opendir(plugindir);
708
perror("Could not open plugin dir");
709
exitstatus = EXIT_FAILURE;
713
/* Set the FD_CLOEXEC flag on the directory, if possible */
879
error(0, errno, "setuid");
882
/* Open plugin directory with close_on_exec flag */
715
int dir_fd = dirfd(dir);
717
ret = set_cloexec_flag(dir_fd);
719
perror("set_cloexec_flag");
720
exitstatus = EXIT_FAILURE;
884
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
887
#else /* not O_CLOEXEC */
889
#endif /* not O_CLOEXEC */
892
error(0, errno, "Could not open plugin dir");
893
exitstatus = EX_UNAVAILABLE;
898
/* Set the FD_CLOEXEC flag on the directory */
899
ret = set_cloexec_flag(dir_fd);
901
error(0, errno, "set_cloexec_flag");
902
exitstatus = EX_OSERR;
905
#endif /* O_CLOEXEC */
908
int good_name(const struct dirent * const dirent){
909
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
910
"*.dpkg-old", "*.dpkg-bak",
911
"*.dpkg-divert", NULL };
913
#pragma GCC diagnostic push
914
#pragma GCC diagnostic ignored "-Wcast-qual"
916
for(const char **pat = (const char **)patterns;
917
*pat != NULL; pat++){
919
#pragma GCC diagnostic pop
921
if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
924
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
925
" matching pattern %s\n", dirent->d_name, *pat);
933
int numplugins = scandirat(dir_fd, ".", &direntries, good_name,
935
if(numplugins == -1){
936
error(0, errno, "Could not scan plugin dir");
938
exitstatus = EX_OSERR;
726
942
FD_ZERO(&rfds_all);
728
944
/* Read and execute any executable in the plugin directory*/
731
dirst = readdir(dir);
732
} while(dirst == NULL and errno == EINTR);
734
/* All directory entries have been processed */
738
exitstatus = EXIT_FAILURE;
744
d_name_len = strlen(dirst->d_name);
746
/* Ignore dotfiles, backup files and other junk */
748
bool bad_name = false;
750
const char const *bad_prefixes[] = { ".", "#", NULL };
752
const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
755
".dpkg-divert", NULL };
756
for(const char **pre = bad_prefixes; *pre != NULL; pre++){
757
size_t pre_len = strlen(*pre);
758
if((d_name_len >= pre_len)
759
and strncmp((dirst->d_name), *pre, pre_len) == 0){
761
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
762
" with bad prefix %s\n", dirst->d_name, *pre);
771
for(const char **suf = bad_suffixes; *suf != NULL; suf++){
772
size_t suf_len = strlen(*suf);
773
if((d_name_len >= suf_len)
774
and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
777
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
778
" with bad suffix %s\n", dirst->d_name, *suf);
791
if(plugindir == NULL){
792
ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, PDIR "/%s",
795
ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, "%s/%s",
945
for(int i = 0; i < numplugins; i++){
947
int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
949
error(0, errno, "Could not open plugin");
804
ret = (int)TEMP_FAILURE_RETRY(stat(filename, &st));
953
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
955
error(0, errno, "stat");
811
961
/* Ignore non-executable files */
812
962
if(not S_ISREG(st.st_mode)
813
or (TEMP_FAILURE_RETRY(access(filename, X_OK)) != 0)){
963
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
815
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
816
" with bad type or mode\n", filename);
966
fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
967
" with bad type or mode\n",
968
plugindir != NULL ? plugindir : PDIR,
969
direntries[i]->d_name);
822
plugin *p = getplugin(dirst->d_name);
976
plugin *p = getplugin(direntries[i]->d_name);
978
error(0, errno, "getplugin");
830
985
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
986
direntries[i]->d_name);
840
996
for(char **a = g->argv + 1; *a != NULL; a++){
841
997
if(not add_argument(p, *a)){
842
perror("add_argument");
998
error(0, errno, "add_argument");
845
1001
/* Add global environment variables */
846
1002
for(char **e = g->environ; *e != NULL; e++){
847
1003
if(not add_environment(p, *e, false)){
848
perror("add_environment");
1004
error(0, errno, "add_environment");
853
/* If this plugin has any environment variables, we will call
854
using execve and need to duplicate the environment from this
1009
/* If this plugin has any environment variables, we need to
1010
duplicate the environment from this process, too. */
856
1011
if(p->environ[0] != NULL){
857
1012
for(char **e = environ; *e != NULL; e++){
858
1013
if(not add_environment(p, *e, false)){
859
perror("add_environment");
1014
error(0, errno, "add_environment");
865
1021
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
1022
#else /* O_CLOEXEC */
1023
ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
1024
#endif /* O_CLOEXEC */
868
exitstatus = EXIT_FAILURE;
1026
error(0, errno, "pipe");
1027
exitstatus = EX_OSERR;
1028
free(direntries[i]);
1031
if(pipefd[0] >= FD_SETSIZE){
1032
fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
1036
exitstatus = EX_OSERR;
1037
free(direntries[i]);
871
1041
/* Ask OS to automatic close the pipe on exec */
872
1042
ret = set_cloexec_flag(pipefd[0]);
874
perror("set_cloexec_flag");
875
exitstatus = EXIT_FAILURE;
1044
error(0, errno, "set_cloexec_flag");
1047
exitstatus = EX_OSERR;
1048
free(direntries[i]);
878
1051
ret = set_cloexec_flag(pipefd[1]);
880
perror("set_cloexec_flag");
881
exitstatus = EXIT_FAILURE;
1053
error(0, errno, "set_cloexec_flag");
1056
exitstatus = EX_OSERR;
1057
free(direntries[i]);
1060
#endif /* not O_CLOEXEC */
884
1061
/* Block SIGCHLD until process is safely in process list */
885
1062
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
886
1063
&sigchld_action.sa_mask,
889
perror("sigprocmask");
890
exitstatus = EXIT_FAILURE;
1066
error(0, errno, "sigprocmask");
1067
exitstatus = EX_OSERR;
1068
free(direntries[i]);
893
1071
/* Starting a new process to be watched */
897
1075
} while(pid == -1 and errno == EINTR);
900
exitstatus = EXIT_FAILURE;
1077
error(0, errno, "fork");
1078
TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1079
&sigchld_action.sa_mask, NULL));
1082
exitstatus = EX_OSERR;
1083
free(direntries[i]);
904
1087
/* this is the child process */
905
1088
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1090
error(0, errno, "sigaction");
910
1093
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
912
perror("sigprocmask");
1095
error(0, errno, "sigprocmask");
916
1099
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1101
error(0, errno, "dup2");
923
/* If dir has no file descriptor, we could not set FD_CLOEXEC
924
above and must now close it manually here. */
927
if(p->environ[0] == NULL){
928
if(execv(filename, p->argv) < 0){
933
if(execve(filename, p->argv, p->environ) < 0){
1105
if(fexecve(plugin_fd, p->argv,
1106
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1107
error(0, errno, "fexecve for %s/%s",
1108
plugindir != NULL ? plugindir : PDIR,
1109
direntries[i]->d_name);
940
1114
/* Parent process */
941
TEMP_FAILURE_RETRY(close(pipefd[1])); /* Close unused write end of
944
plugin *new_plugin = getplugin(dirst->d_name);
1115
close(pipefd[1]); /* Close unused write end of pipe */
1117
plugin *new_plugin = getplugin(direntries[i]->d_name);
945
1118
if(new_plugin == NULL){
1119
error(0, errno, "getplugin");
947
1120
ret = (int)(TEMP_FAILURE_RETRY
948
1121
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
951
perror("sigprocmask");
1124
error(0, errno, "sigprocmask");
953
exitstatus = EXIT_FAILURE;
1126
exitstatus = EX_OSERR;
1127
free(direntries[i]);
1130
free(direntries[i]);
957
1132
new_plugin->pid = pid;
958
1133
new_plugin->fd = pipefd[0];
1136
fprintf(stderr, "Plugin %s started (PID %" PRIdMAX ")\n",
1137
new_plugin->name, (intmax_t) (new_plugin->pid));
960
1140
/* Unblock SIGCHLD so signal handler can be run if this process
961
1141
has already completed */
962
1142
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
963
1143
&sigchld_action.sa_mask,
966
perror("sigprocmask");
967
exitstatus = EXIT_FAILURE;
1146
error(0, errno, "sigprocmask");
1147
exitstatus = EX_OSERR;