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 © 2008-2021 Teddy Hogeborn
6
* Copyright © 2008-2021 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
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
26
asprintf(), O_CLOEXEC */
26
#define _GNU_SOURCE /* strchrnul(), TEMP_FAILURE_RETRY(),
27
getline(), asprintf(), O_CLOEXEC,
28
scandirat(), pipe2() */
29
#include <argp.h> /* argp_program_version,
30
argp_program_bug_address,
32
struct argp_state, argp_error(),
33
ARGP_NO_EXIT, argp_state_help,
35
ARGP_HELP_USAGE, ARGP_HELP_EXIT_OK,
36
ARGP_KEY_ARG, ARGP_ERR_UNKNOWN,
37
struct argp, argp_parse(),
38
ARGP_IN_ORDER, ARGP_NO_HELP */
39
#include <stdbool.h> /* bool, false, true */
40
#include <sys/types.h> /* pid_t, sig_atomic_t, uid_t, gid_t,
41
getuid(), setgid(), setuid() */
27
42
#include <stddef.h> /* size_t, NULL */
28
#include <stdlib.h> /* malloc(), exit(), EXIT_FAILURE,
29
EXIT_SUCCESS, realloc() */
30
#include <stdbool.h> /* bool, true, false */
31
#include <stdio.h> /* perror, fileno(), fprintf(),
32
stderr, STDOUT_FILENO */
33
#include <sys/types.h> /* DIR, fdopendir(), stat(), struct
34
stat, waitpid(), WIFEXITED(),
35
WEXITSTATUS(), wait(), pid_t,
36
uid_t, gid_t, getuid(), getgid(),
38
#include <sys/select.h> /* fd_set, select(), FD_ZERO(),
39
FD_SET(), FD_ISSET(), FD_CLR */
40
#include <sys/wait.h> /* wait(), waitpid(), WIFEXITED(),
41
WEXITSTATUS(), WTERMSIG(),
43
#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
44
#include <iso646.h> /* and, or, not */
45
#include <dirent.h> /* DIR, struct dirent, fdopendir(),
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(),
43
#include <iso646.h> /* or, and, not */
44
#include <string.h> /* strcmp(), strdup(), strchrnul(),
45
strncmp(), strlen(), strcpy(),
46
strsep(), strchr(), strsignal() */
47
#include <stdlib.h> /* malloc(), free(), reallocarray(),
48
realloc(), EXIT_SUCCESS */
49
#include <errno.h> /* errno, EINTR, ENOMEM, ECHILD,
50
error_t, EINVAL, EMFILE, ENFILE,
52
#include <stdint.h> /* SIZE_MAX */
53
#define _GNU_SOURCE /* strchrnul(), TEMP_FAILURE_RETRY(),
54
getline(), asprintf(), O_CLOEXEC,
55
scandirat(), pipe2() */
56
#include <unistd.h> /* TEMP_FAILURE_RETRY(), ssize_t,
57
write(), STDOUT_FILENO, uid_t,
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gid_t, getuid(), fchown(), close(),
59
symlink(), setgid(), setuid(),
60
faccessat(), X_OK, pipe(), pipe2(),
61
fork(), _exit(), dup2(), fexecve(),
54
63
#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
56
#include <string.h> /* strsep, strlen(), asprintf(),
58
#include <errno.h> /* errno */
59
#include <argp.h> /* struct argp_option, struct
60
argp_state, struct argp,
61
argp_parse(), ARGP_ERR_UNKNOWN,
62
ARGP_KEY_END, ARGP_KEY_ARG,
64
#include <signal.h> /* struct sigaction, sigemptyset(),
65
sigaddset(), sigaction(),
66
sigprocmask(), SIG_BLOCK, SIGCHLD,
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SIG_UNBLOCK, kill(), sig_atomic_t
69
#include <errno.h> /* errno, EBADF */
70
#include <inttypes.h> /* intmax_t, PRIdMAX, strtoimax() */
71
#include <sysexits.h> /* EX_OSERR, EX_USAGE */
64
FD_CLOEXEC, open(), O_RDONLY,
65
O_CLOEXEC, openat() */
66
#include <sys/wait.h> /* waitpid(), WNOHANG, WIFEXITED(),
67
WEXITSTATUS(), WIFSIGNALED(),
69
#include <error.h> /* error() */
70
#include <stdio.h> /* FILE, fprintf(), fopen(),
71
getline(), fclose(), EOF,
73
#include <dirent.h> /* struct dirent, scandirat(),
75
#include <sys/stat.h> /* struct stat, fstat(), S_ISDIR(),
77
#include <sys/select.h> /* fd_set, FD_ZERO(), FD_SETSIZE,
78
FD_SET(), select(), FD_CLR(),
80
#include <signal.h> /* struct sigaction, SA_NOCLDSTOP,
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sigemptyset(), sigaddset(),
82
SIGCHLD, sigprocmask(), SIG_BLOCK,
83
SIG_UNBLOCK, kill(), SIGTERM */
84
#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_IOERR,
85
EX_CONFIG, EX_UNAVAILABLE, EX_OK */
86
#include <inttypes.h> /* intmax_t, strtoimax(), PRIdMAX */
87
#include <fnmatch.h> /* fnmatch(), FNM_FILE_NAME,
88
FNM_PERIOD, FNM_NOMATCH */
73
90
#define BUFFER_SIZE 256
75
92
#define PDIR "/lib/mandos/plugins.d"
93
#define PHDIR "/lib/mandos/plugin-helpers"
76
94
#define AFILE "/conf/conf.d/mandos/plugin-runner.conf"
78
96
const char *argp_program_version = "plugin-runner " VERSION;
79
const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
97
const char *argp_program_bug_address = "<mandos@recompile.se>";
81
99
typedef struct plugin{
82
100
char *name; /* can be NULL or any plugin name */
485
538
plugin *p = getplugin(arg);
487
540
p->disabled = false;
491
545
case 128: /* --plugin-dir */
493
547
plugindir = strdup(arg);
548
if(plugindir != NULL){
495
552
case 129: /* --config-file */
496
553
/* This is already done by parse_opt_config_file() */
498
555
case 130: /* --userid */
499
tmpmax = strtoimax(arg, &tmp, 10);
556
tmp_id = strtoimax(arg, &tmp, 10);
500
557
if(errno != 0 or tmp == arg or *tmp != '\0'
501
or tmpmax != (uid_t)tmpmax){
558
or tmp_id != (uid_t)tmp_id){
502
559
argp_error(state, "Bad user ID number: \"%s\", using %"
503
560
PRIdMAX, arg, (intmax_t)uid);
508
566
case 131: /* --groupid */
509
tmpmax = strtoimax(arg, &tmp, 10);
567
tmp_id = strtoimax(arg, &tmp, 10);
510
568
if(errno != 0 or tmp == arg or *tmp != '\0'
511
or tmpmax != (gid_t)tmpmax){
569
or tmp_id != (gid_t)tmp_id){
512
570
argp_error(state, "Bad group ID number: \"%s\", using %"
513
571
PRIdMAX, arg, (intmax_t)gid);
518
577
case 132: /* --debug */
580
case 133: /* --plugin-helper-dir */
581
free(pluginhelperdir);
582
pluginhelperdir = strdup(arg);
583
if(pluginhelperdir != NULL){
522
588
* These reproduce what we would get without ARGP_NO_HELP
524
590
case '?': /* --help */
525
591
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
526
592
argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
593
__builtin_unreachable();
527
594
case -3: /* --usage */
528
595
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
529
596
argp_state_help(state, state->out_stream,
530
597
ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
598
__builtin_unreachable();
531
599
case 'V': /* --version */
532
600
fprintf(state->out_stream, "%s\n", argp_program_version);
533
601
exit(EXIT_SUCCESS);
742
/* Strip permissions down to nobody */
854
/* Work around Debian bug #633582:
855
<https://bugs.debian.org/633582> */
856
int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
857
if(plugindir_fd == -1){
859
error(0, errno, "open(\"" PDIR "\")");
862
ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
864
error(0, errno, "fstat");
866
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
867
ret = fchown(plugindir_fd, uid, gid);
869
error(0, errno, "fchown");
876
/* Work around Debian bug #981302
877
<https://bugs.debian.org/981302> */
878
if(lstat("/dev/fd", &st) != 0 and errno == ENOENT){
879
ret = symlink("/proc/self/fd", "/dev/fd");
881
error(0, errno, "Failed to create /dev/fd symlink");
886
/* Lower permissions */
889
error(0, errno, "setgid");
747
891
ret = setuid(uid);
893
error(0, errno, "setuid");
752
896
/* Open plugin directory with close_on_exec flag */
755
if(plugindir == NULL){
756
dir_fd = open(PDIR, O_RDONLY |
759
#else /* not O_CLOEXEC */
761
#endif /* not O_CLOEXEC */
764
dir_fd = open(plugindir, O_RDONLY |
767
#else /* not O_CLOEXEC */
769
#endif /* not O_CLOEXEC */
898
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
901
#else /* not O_CLOEXEC */
903
#endif /* not O_CLOEXEC */
772
905
if(dir_fd == -1){
773
perror("Could not open plugin dir");
774
exitstatus = EXIT_FAILURE;
906
error(0, errno, "Could not open plugin dir");
907
exitstatus = EX_UNAVAILABLE;
779
912
/* Set the FD_CLOEXEC flag on the directory */
780
913
ret = set_cloexec_flag(dir_fd);
782
perror("set_cloexec_flag");
783
TEMP_FAILURE_RETRY(close(dir_fd));
784
exitstatus = EXIT_FAILURE;
915
error(0, errno, "set_cloexec_flag");
916
exitstatus = EX_OSERR;
787
919
#endif /* O_CLOEXEC */
789
dir = fdopendir(dir_fd);
791
perror("Could not open plugin dir");
792
TEMP_FAILURE_RETRY(close(dir_fd));
793
exitstatus = EXIT_FAILURE;
922
int good_name(const struct dirent * const dirent){
923
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
924
"*.dpkg-old", "*.dpkg-bak",
925
"*.dpkg-divert", NULL };
927
#pragma GCC diagnostic push
928
#pragma GCC diagnostic ignored "-Wcast-qual"
930
for(const char **pat = (const char **)patterns;
931
*pat != NULL; pat++){
933
#pragma GCC diagnostic pop
935
if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
938
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
939
" matching pattern %s\n", dirent->d_name, *pat);
947
int numplugins = scandirat(dir_fd, ".", &direntries, good_name,
949
if(numplugins == -1){
950
error(0, errno, "Could not scan plugin dir");
952
exitstatus = EX_OSERR;
798
956
FD_ZERO(&rfds_all);
800
958
/* Read and execute any executable in the plugin directory*/
803
dirst = readdir(dir);
804
} while(dirst == NULL and errno == EINTR);
806
/* All directory entries have been processed */
810
exitstatus = EXIT_FAILURE;
816
d_name_len = strlen(dirst->d_name);
818
/* Ignore dotfiles, backup files and other junk */
820
bool bad_name = false;
822
const char const *bad_prefixes[] = { ".", "#", NULL };
824
const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
827
".dpkg-divert", NULL };
828
for(const char **pre = bad_prefixes; *pre != NULL; pre++){
829
size_t pre_len = strlen(*pre);
830
if((d_name_len >= pre_len)
831
and strncmp((dirst->d_name), *pre, pre_len) == 0){
833
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
834
" with bad prefix %s\n", dirst->d_name, *pre);
843
for(const char **suf = bad_suffixes; *suf != NULL; suf++){
844
size_t suf_len = strlen(*suf);
845
if((d_name_len >= suf_len)
846
and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
849
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
850
" with bad suffix %s\n", dirst->d_name, *suf);
863
if(plugindir == NULL){
864
ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, PDIR "/%s",
867
ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, "%s/%s",
959
for(int i = 0; i < numplugins; i++){
961
int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
963
error(0, errno, "Could not open plugin");
876
ret = (int)TEMP_FAILURE_RETRY(stat(filename, &st));
967
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
969
error(0, errno, "stat");
883
975
/* Ignore non-executable files */
884
976
if(not S_ISREG(st.st_mode)
885
or (TEMP_FAILURE_RETRY(access(filename, X_OK)) != 0)){
977
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
887
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
888
" with bad type or mode\n", filename);
980
fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
981
" with bad type or mode\n",
982
plugindir != NULL ? plugindir : PDIR,
983
direntries[i]->d_name);
894
plugin *p = getplugin(dirst->d_name);
990
plugin *p = getplugin(direntries[i]->d_name);
992
error(0, errno, "getplugin");
902
999
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
1000
direntries[i]->d_name);
1003
free(direntries[i]);
912
1010
for(char **a = g->argv + 1; *a != NULL; a++){
913
1011
if(not add_argument(p, *a)){
914
perror("add_argument");
1012
error(0, errno, "add_argument");
917
1015
/* Add global environment variables */
918
1016
for(char **e = g->environ; *e != NULL; e++){
919
1017
if(not add_environment(p, *e, false)){
920
perror("add_environment");
1018
error(0, errno, "add_environment");
925
/* If this plugin has any environment variables, we will call
926
using execve and need to duplicate the environment from this
1023
/* If this plugin has any environment variables, we need to
1024
duplicate the environment from this process, too. */
928
1025
if(p->environ[0] != NULL){
929
1026
for(char **e = environ; *e != NULL; e++){
930
1027
if(not add_environment(p, *e, false)){
931
perror("add_environment");
1028
error(0, errno, "add_environment");
937
1035
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
1036
#else /* O_CLOEXEC */
1037
ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
1038
#endif /* O_CLOEXEC */
940
exitstatus = EXIT_FAILURE;
1040
error(0, errno, "pipe");
1041
exitstatus = EX_OSERR;
1042
free(direntries[i]);
1045
if(pipefd[0] >= FD_SETSIZE){
1046
fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
1050
exitstatus = EX_OSERR;
1051
free(direntries[i]);
943
1055
/* Ask OS to automatic close the pipe on exec */
944
1056
ret = set_cloexec_flag(pipefd[0]);
946
perror("set_cloexec_flag");
947
exitstatus = EXIT_FAILURE;
1058
error(0, errno, "set_cloexec_flag");
1061
exitstatus = EX_OSERR;
1062
free(direntries[i]);
950
1065
ret = set_cloexec_flag(pipefd[1]);
952
perror("set_cloexec_flag");
953
exitstatus = EXIT_FAILURE;
1067
error(0, errno, "set_cloexec_flag");
1070
exitstatus = EX_OSERR;
1071
free(direntries[i]);
1074
#endif /* not O_CLOEXEC */
956
1075
/* Block SIGCHLD until process is safely in process list */
957
1076
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
958
1077
&sigchld_action.sa_mask,
961
perror("sigprocmask");
962
exitstatus = EXIT_FAILURE;
1080
error(0, errno, "sigprocmask");
1081
exitstatus = EX_OSERR;
1082
free(direntries[i]);
965
1085
/* Starting a new process to be watched */
969
1089
} while(pid == -1 and errno == EINTR);
972
exitstatus = EXIT_FAILURE;
1091
error(0, errno, "fork");
1092
TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1093
&sigchld_action.sa_mask, NULL));
1096
exitstatus = EX_OSERR;
1097
free(direntries[i]);
976
1101
/* this is the child process */
977
1102
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1104
error(0, errno, "sigaction");
982
1107
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
984
perror("sigprocmask");
1109
error(0, errno, "sigprocmask");
988
1113
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1115
error(0, errno, "dup2");
995
/* If dir has no file descriptor, we could not set FD_CLOEXEC
996
above and must now close it manually here. */
999
if(p->environ[0] == NULL){
1000
if(execv(filename, p->argv) < 0){
1002
_exit(EXIT_FAILURE);
1005
if(execve(filename, p->argv, p->environ) < 0){
1007
_exit(EXIT_FAILURE);
1119
if(fexecve(plugin_fd, p->argv,
1120
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1121
error(0, errno, "fexecve for %s/%s",
1122
plugindir != NULL ? plugindir : PDIR,
1123
direntries[i]->d_name);
1010
1126
/* no return */
1012
1128
/* Parent process */
1013
TEMP_FAILURE_RETRY(close(pipefd[1])); /* Close unused write end of
1016
plugin *new_plugin = getplugin(dirst->d_name);
1129
close(pipefd[1]); /* Close unused write end of pipe */
1131
plugin *new_plugin = getplugin(direntries[i]->d_name);
1017
1132
if(new_plugin == NULL){
1018
perror("getplugin");
1133
error(0, errno, "getplugin");
1019
1134
ret = (int)(TEMP_FAILURE_RETRY
1020
1135
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
1023
perror("sigprocmask");
1138
error(0, errno, "sigprocmask");
1025
exitstatus = EXIT_FAILURE;
1140
exitstatus = EX_OSERR;
1141
free(direntries[i]);
1144
free(direntries[i]);
1029
1146
new_plugin->pid = pid;
1030
1147
new_plugin->fd = pipefd[0];
1150
fprintf(stderr, "Plugin %s started (PID %" PRIdMAX ")\n",
1151
new_plugin->name, (intmax_t) (new_plugin->pid));
1032
1154
/* Unblock SIGCHLD so signal handler can be run if this process
1033
1155
has already completed */
1034
1156
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1035
1157
&sigchld_action.sa_mask,
1038
perror("sigprocmask");
1039
exitstatus = EXIT_FAILURE;
1160
error(0, errno, "sigprocmask");
1161
exitstatus = EX_OSERR;
1043
FD_SET(new_plugin->fd, &rfds_all); /* Spurious warning from
1165
FD_SET(new_plugin->fd, &rfds_all);
1046
1167
if(maxfd < new_plugin->fd){
1047
1168
maxfd = new_plugin->fd;
1051
TEMP_FAILURE_RETRY(closedir(dir));
1053
1176
free_plugin(getplugin(NULL));
1055
1178
for(plugin *p = plugin_list; p != NULL; p = p->next){