3
3
* Mandos plugin runner - Run Mandos plugins
5
* Copyright © 2008-2022 Teddy Hogeborn
6
* Copyright © 2008-2022 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
#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() */
25
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),
26
asprintf(), O_CLOEXEC */
42
27
#include <stddef.h> /* size_t, NULL */
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,
58
gid_t, getuid(), fchown(), close(),
59
symlink(), setgid(), setuid(),
60
faccessat(), X_OK, pipe(), pipe2(),
61
fork(), _exit(), dup2(), fexecve(),
28
#include <stdlib.h> /* malloc(), exit(), EXIT_SUCCESS,
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,
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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(),
63
54
#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,
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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() */
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#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,
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FD_SET(), select(), FD_CLR(),
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#include <signal.h> /* struct sigaction, SA_NOCLDSTOP,
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sigemptyset(), sigaddset(),
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SIGCHLD, sigprocmask(), SIG_BLOCK,
83
SIG_UNBLOCK, kill(), SIGTERM */
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,
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ARGP_KEY_END, ARGP_KEY_ARG,
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#include <signal.h> /* struct sigaction, sigemptyset(),
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sigaddset(), sigaction(),
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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() */
84
71
#include <sysexits.h> /* EX_OSERR, EX_USAGE, EX_IOERR,
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EX_CONFIG, EX_UNAVAILABLE, EX_OK */
86
#include <inttypes.h> /* intmax_t, strtoimax(), PRIdMAX */
87
#include <fnmatch.h> /* fnmatch(), FNM_FILE_NAME,
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FNM_PERIOD, FNM_NOMATCH */
90
74
#define BUFFER_SIZE 256
92
76
#define PDIR "/lib/mandos/plugins.d"
93
#define PHDIR "/lib/mandos/plugin-helpers"
94
77
#define AFILE "/conf/conf.d/mandos/plugin-runner.conf"
96
79
const char *argp_program_version = "plugin-runner " VERSION;
97
const char *argp_program_bug_address = "<mandos@recompile.se>";
80
const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
99
82
typedef struct plugin{
100
83
char *name; /* can be NULL or any plugin name */
538
486
plugin *p = getplugin(arg);
540
488
p->disabled = false;
545
492
case 128: /* --plugin-dir */
547
494
plugindir = strdup(arg);
548
if(plugindir != NULL){
552
496
case 129: /* --config-file */
553
497
/* This is already done by parse_opt_config_file() */
555
499
case 130: /* --userid */
556
tmp_id = strtoimax(arg, &tmp, 10);
500
tmpmax = strtoimax(arg, &tmp, 10);
557
501
if(errno != 0 or tmp == arg or *tmp != '\0'
558
or tmp_id != (uid_t)tmp_id){
502
or tmpmax != (uid_t)tmpmax){
559
503
argp_error(state, "Bad user ID number: \"%s\", using %"
560
504
PRIdMAX, arg, (intmax_t)uid);
566
509
case 131: /* --groupid */
567
tmp_id = strtoimax(arg, &tmp, 10);
510
tmpmax = strtoimax(arg, &tmp, 10);
568
511
if(errno != 0 or tmp == arg or *tmp != '\0'
569
or tmp_id != (gid_t)tmp_id){
512
or tmpmax != (gid_t)tmpmax){
570
513
argp_error(state, "Bad group ID number: \"%s\", using %"
571
514
PRIdMAX, arg, (intmax_t)gid);
577
519
case 132: /* --debug */
580
case 133: /* --plugin-helper-dir */
581
free(pluginhelperdir);
582
pluginhelperdir = strdup(arg);
583
if(pluginhelperdir != NULL){
588
523
* These reproduce what we would get without ARGP_NO_HELP
590
525
case '?': /* --help */
591
526
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
592
527
argp_state_help(state, state->out_stream, ARGP_HELP_STD_HELP);
593
__builtin_unreachable();
594
528
case -3: /* --usage */
595
529
state->flags &= ~(unsigned int)ARGP_NO_EXIT; /* force exit */
596
530
argp_state_help(state, state->out_stream,
597
531
ARGP_HELP_USAGE | ARGP_HELP_EXIT_OK);
598
__builtin_unreachable();
599
532
case 'V': /* --version */
600
533
fprintf(state->out_stream, "%s\n", argp_program_version);
601
534
exit(EXIT_SUCCESS);
855
/* Work around Debian bug #633582:
856
<https://bugs.debian.org/633582> */
857
int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
858
if(plugindir_fd == -1){
860
error(0, errno, "open(\"" PDIR "\")");
863
ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
865
error(0, errno, "fstat");
867
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
868
ret = fchown(plugindir_fd, uid, gid);
870
error(0, errno, "fchown");
877
/* Work around Debian bug #981302
878
<https://bugs.debian.org/981302> */
879
if(lstat("/dev/fd", &st) != 0 and errno == ENOENT){
880
ret = symlink("/proc/self/fd", "/dev/fd");
882
error(0, errno, "Failed to create /dev/fd symlink");
887
/* Lower permissions */
743
/* Strip permissions down to nobody */
890
error(0, errno, "setgid");
892
748
ret = setuid(uid);
894
error(0, errno, "setuid");
897
753
/* Open plugin directory with close_on_exec flag */
899
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
902
#else /* not O_CLOEXEC */
904
#endif /* not O_CLOEXEC */
756
if(plugindir == NULL){
757
dir_fd = open(PDIR, O_RDONLY |
760
#else /* not O_CLOEXEC */
762
#endif /* not O_CLOEXEC */
765
dir_fd = open(plugindir, O_RDONLY |
768
#else /* not O_CLOEXEC */
770
#endif /* not O_CLOEXEC */
906
773
if(dir_fd == -1){
907
error(0, errno, "Could not open plugin dir");
774
perror("Could not open plugin dir");
908
775
exitstatus = EX_UNAVAILABLE;
913
780
/* Set the FD_CLOEXEC flag on the directory */
914
781
ret = set_cloexec_flag(dir_fd);
916
error(0, errno, "set_cloexec_flag");
783
perror("set_cloexec_flag");
784
TEMP_FAILURE_RETRY(close(dir_fd));
917
785
exitstatus = EX_OSERR;
920
788
#endif /* O_CLOEXEC */
923
int good_name(const struct dirent * const dirent){
924
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
925
"*.dpkg-old", "*.dpkg-bak",
926
"*.dpkg-divert", NULL };
928
#pragma GCC diagnostic push
929
#pragma GCC diagnostic ignored "-Wcast-qual"
931
for(const char **pat = (const char **)patterns;
932
*pat != NULL; pat++){
934
#pragma GCC diagnostic pop
936
if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
939
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
940
" matching pattern %s\n", dirent->d_name, *pat);
790
dir = fdopendir(dir_fd);
792
perror("Could not open plugin dir");
793
TEMP_FAILURE_RETRY(close(dir_fd));
794
exitstatus = EX_OSERR;
948
int numplugins = scandirat(dir_fd, ".", &direntries, good_name,
950
if(numplugins == -1){
951
error(0, errno, "Could not scan plugin dir");
953
exitstatus = EX_OSERR;
957
799
FD_ZERO(&rfds_all);
959
801
/* Read and execute any executable in the plugin directory*/
960
for(int i = 0; i < numplugins; i++){
962
int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
964
error(0, errno, "Could not open plugin");
804
dirst = readdir(dir);
805
} while(dirst == NULL and errno == EINTR);
807
/* All directory entries have been processed */
811
exitstatus = EX_IOERR;
817
d_name_len = strlen(dirst->d_name);
819
/* Ignore dotfiles, backup files and other junk */
821
bool bad_name = false;
823
const char const *bad_prefixes[] = { ".", "#", NULL };
825
const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
828
".dpkg-divert", NULL };
829
for(const char **pre = bad_prefixes; *pre != NULL; pre++){
830
size_t pre_len = strlen(*pre);
831
if((d_name_len >= pre_len)
832
and strncmp((dirst->d_name), *pre, pre_len) == 0){
834
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
835
" with bad prefix %s\n", dirst->d_name, *pre);
844
for(const char **suf = bad_suffixes; *suf != NULL; suf++){
845
size_t suf_len = strlen(*suf);
846
if((d_name_len >= suf_len)
847
and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
850
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
851
" with bad suffix %s\n", dirst->d_name, *suf);
864
if(plugindir == NULL){
865
ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, PDIR "/%s",
868
ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, "%s/%s",
968
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
877
ret = (int)TEMP_FAILURE_RETRY(stat(filename, &st));
970
error(0, errno, "stat");
976
884
/* Ignore non-executable files */
977
885
if(not S_ISREG(st.st_mode)
978
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
886
or (TEMP_FAILURE_RETRY(access(filename, X_OK)) != 0)){
981
fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
982
" with bad type or mode\n",
983
plugindir != NULL ? plugindir : PDIR,
984
direntries[i]->d_name);
888
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
889
" with bad type or mode\n", filename);
991
plugin *p = getplugin(direntries[i]->d_name);
895
plugin *p = getplugin(dirst->d_name);
993
error(0, errno, "getplugin");
1000
903
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
1001
direntries[i]->d_name);
1004
free(direntries[i]);
1011
913
for(char **a = g->argv + 1; *a != NULL; a++){
1012
914
if(not add_argument(p, *a)){
1013
error(0, errno, "add_argument");
915
perror("add_argument");
1016
918
/* Add global environment variables */
1017
919
for(char **e = g->environ; *e != NULL; e++){
1018
920
if(not add_environment(p, *e, false)){
1019
error(0, errno, "add_environment");
921
perror("add_environment");
1024
/* If this plugin has any environment variables, we need to
1025
duplicate the environment from this process, too. */
926
/* If this plugin has any environment variables, we will call
927
using execve and need to duplicate the environment from this
1026
929
if(p->environ[0] != NULL){
1027
930
for(char **e = environ; *e != NULL; e++){
1028
931
if(not add_environment(p, *e, false)){
1029
error(0, errno, "add_environment");
932
perror("add_environment");
1036
938
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
1037
#else /* O_CLOEXEC */
1038
ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
1039
#endif /* O_CLOEXEC */
1041
error(0, errno, "pipe");
1042
exitstatus = EX_OSERR;
1043
free(direntries[i]);
1046
if(pipefd[0] >= FD_SETSIZE){
1047
fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
1051
exitstatus = EX_OSERR;
1052
free(direntries[i]);
941
exitstatus = EX_OSERR;
1056
944
/* Ask OS to automatic close the pipe on exec */
1057
945
ret = set_cloexec_flag(pipefd[0]);
1059
error(0, errno, "set_cloexec_flag");
947
perror("set_cloexec_flag");
1062
948
exitstatus = EX_OSERR;
1063
free(direntries[i]);
1066
951
ret = set_cloexec_flag(pipefd[1]);
1068
error(0, errno, "set_cloexec_flag");
953
perror("set_cloexec_flag");
1071
954
exitstatus = EX_OSERR;
1072
free(direntries[i]);
1075
#endif /* not O_CLOEXEC */
1076
957
/* Block SIGCHLD until process is safely in process list */
1077
958
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
1078
959
&sigchld_action.sa_mask,
1081
error(0, errno, "sigprocmask");
962
perror("sigprocmask");
1082
963
exitstatus = EX_OSERR;
1083
free(direntries[i]);
1086
966
/* Starting a new process to be watched */
1090
970
} while(pid == -1 and errno == EINTR);
1092
error(0, errno, "fork");
1093
TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1094
&sigchld_action.sa_mask, NULL));
1097
973
exitstatus = EX_OSERR;
1098
free(direntries[i]);
1102
977
/* this is the child process */
1103
978
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1105
error(0, errno, "sigaction");
1106
981
_exit(EX_OSERR);
1108
983
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1110
error(0, errno, "sigprocmask");
985
perror("sigprocmask");
1111
986
_exit(EX_OSERR);
1114
989
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1116
error(0, errno, "dup2");
1117
992
_exit(EX_OSERR);
1120
if(fexecve(plugin_fd, p->argv,
1121
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1122
error(0, errno, "fexecve for %s/%s",
1123
plugindir != NULL ? plugindir : PDIR,
1124
direntries[i]->d_name);
996
/* If dir has no file descriptor, we could not set FD_CLOEXEC
997
above and must now close it manually here. */
1000
if(p->environ[0] == NULL){
1001
if(execv(filename, p->argv) < 0){
1006
if(execve(filename, p->argv, p->environ) < 0){
1127
1011
/* no return */
1129
1013
/* Parent process */
1130
close(pipefd[1]); /* Close unused write end of pipe */
1132
plugin *new_plugin = getplugin(direntries[i]->d_name);
1014
TEMP_FAILURE_RETRY(close(pipefd[1])); /* Close unused write end of
1017
plugin *new_plugin = getplugin(dirst->d_name);
1133
1018
if(new_plugin == NULL){
1134
error(0, errno, "getplugin");
1019
perror("getplugin");
1135
1020
ret = (int)(TEMP_FAILURE_RETRY
1136
1021
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
1139
error(0, errno, "sigprocmask");
1024
perror("sigprocmask");
1141
1026
exitstatus = EX_OSERR;
1142
free(direntries[i]);
1145
free(direntries[i]);
1147
1030
new_plugin->pid = pid;
1148
1031
new_plugin->fd = pipefd[0];
1151
fprintf(stderr, "Plugin %s started (PID %" PRIdMAX ")\n",
1152
new_plugin->name, (intmax_t) (new_plugin->pid));
1155
1033
/* Unblock SIGCHLD so signal handler can be run if this process
1156
1034
has already completed */
1157
1035
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1158
1036
&sigchld_action.sa_mask,
1161
error(0, errno, "sigprocmask");
1039
perror("sigprocmask");
1162
1040
exitstatus = EX_OSERR;
1166
FD_SET(new_plugin->fd, &rfds_all);
1044
FD_SET(new_plugin->fd, &rfds_all); /* Spurious warning from
1168
1047
if(maxfd < new_plugin->fd){
1169
1048
maxfd = new_plugin->fd;
1052
TEMP_FAILURE_RETRY(closedir(dir));
1177
1054
free_plugin(getplugin(NULL));
1179
1056
for(plugin *p = plugin_list; p != NULL; p = p->next){