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(),
26
asprintf(), O_CLOEXEC */
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, fdopendir(), 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, 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(),
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,
512
485
plugin *p = getplugin(arg);
514
487
p->disabled = false;
519
491
case 128: /* --plugin-dir */
521
493
plugindir = strdup(arg);
522
if(plugindir != NULL){
526
495
case 129: /* --config-file */
527
496
/* This is already done by parse_opt_config_file() */
529
498
case 130: /* --userid */
530
tmp_id = strtoimax(arg, &tmp, 10);
499
tmpmax = strtoimax(arg, &tmp, 10);
531
500
if(errno != 0 or tmp == arg or *tmp != '\0'
532
or tmp_id != (uid_t)tmp_id){
501
or tmpmax != (uid_t)tmpmax){
533
502
argp_error(state, "Bad user ID number: \"%s\", using %"
534
503
PRIdMAX, arg, (intmax_t)uid);
540
508
case 131: /* --groupid */
541
tmp_id = strtoimax(arg, &tmp, 10);
509
tmpmax = strtoimax(arg, &tmp, 10);
542
510
if(errno != 0 or tmp == arg or *tmp != '\0'
543
or tmp_id != (gid_t)tmp_id){
511
or tmpmax != (gid_t)tmpmax){
544
512
argp_error(state, "Bad group ID number: \"%s\", using %"
545
513
PRIdMAX, arg, (intmax_t)gid);
551
518
case 132: /* --debug */
554
case 133: /* --plugin-helper-dir */
555
free(pluginhelperdir);
556
pluginhelperdir = strdup(arg);
557
if(pluginhelperdir != NULL){
562
522
* These reproduce what we would get without ARGP_NO_HELP
810
/* Work around Debian bug #633582:
811
<https://bugs.debian.org/633582> */
812
int plugindir_fd = open(/* plugindir or */ PDIR, O_RDONLY);
813
if(plugindir_fd == -1){
815
error(0, errno, "open(\"" PDIR "\")");
818
ret = (int)TEMP_FAILURE_RETRY(fstat(plugindir_fd, &st));
820
error(0, errno, "fstat");
822
if(S_ISDIR(st.st_mode) and st.st_uid == 0 and st.st_gid == 0){
823
ret = fchown(plugindir_fd, uid, gid);
825
error(0, errno, "fchown");
833
/* Lower permissions */
742
/* Strip permissions down to nobody */
836
error(0, errno, "setgid");
838
747
ret = setuid(uid);
840
error(0, errno, "setuid");
843
752
/* Open plugin directory with close_on_exec flag */
845
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
848
#else /* not O_CLOEXEC */
850
#endif /* not O_CLOEXEC */
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 */
852
772
if(dir_fd == -1){
853
error(0, errno, "Could not open plugin dir");
854
exitstatus = EX_UNAVAILABLE;
773
perror("Could not open plugin dir");
774
exitstatus = EXIT_FAILURE;
859
779
/* Set the FD_CLOEXEC flag on the directory */
860
780
ret = set_cloexec_flag(dir_fd);
862
error(0, errno, "set_cloexec_flag");
863
exitstatus = EX_OSERR;
782
perror("set_cloexec_flag");
783
TEMP_FAILURE_RETRY(close(dir_fd));
784
exitstatus = EXIT_FAILURE;
866
787
#endif /* O_CLOEXEC */
869
int good_name(const struct dirent * const dirent){
870
const char * const patterns[] = { ".*", "#*#", "*~", "*.dpkg-new",
871
"*.dpkg-old", "*.dpkg-bak",
872
"*.dpkg-divert", NULL };
874
#pragma GCC diagnostic push
875
#pragma GCC diagnostic ignored "-Wcast-qual"
877
for(const char **pat = (const char **)patterns;
878
*pat != NULL; pat++){
880
#pragma GCC diagnostic pop
882
if(fnmatch(*pat, dirent->d_name, FNM_FILE_NAME | FNM_PERIOD)
885
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
886
" matching pattern %s\n", dirent->d_name, *pat);
789
dir = fdopendir(dir_fd);
791
perror("Could not open plugin dir");
792
TEMP_FAILURE_RETRY(close(dir_fd));
793
exitstatus = EXIT_FAILURE;
894
int numplugins = scandirat(dir_fd, ".", &direntries, good_name,
896
if(numplugins == -1){
897
error(0, errno, "Could not scan plugin dir");
899
exitstatus = EX_OSERR;
903
798
FD_ZERO(&rfds_all);
905
800
/* Read and execute any executable in the plugin directory*/
906
for(int i = 0; i < numplugins; i++){
908
int plugin_fd = openat(dir_fd, direntries[i]->d_name, O_RDONLY);
910
error(0, errno, "Could not open plugin");
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",
914
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
876
ret = (int)TEMP_FAILURE_RETRY(stat(filename, &st));
916
error(0, errno, "stat");
922
883
/* Ignore non-executable files */
923
884
if(not S_ISREG(st.st_mode)
924
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
885
or (TEMP_FAILURE_RETRY(access(filename, X_OK)) != 0)){
927
fprintf(stderr, "Ignoring plugin dir entry \"%s/%s\""
928
" with bad type or mode\n",
929
plugindir != NULL ? plugindir : PDIR,
930
direntries[i]->d_name);
887
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
888
" with bad type or mode\n", filename);
937
plugin *p = getplugin(direntries[i]->d_name);
894
plugin *p = getplugin(dirst->d_name);
939
error(0, errno, "getplugin");
946
902
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
947
direntries[i]->d_name);
957
912
for(char **a = g->argv + 1; *a != NULL; a++){
958
913
if(not add_argument(p, *a)){
959
error(0, errno, "add_argument");
914
perror("add_argument");
962
917
/* Add global environment variables */
963
918
for(char **e = g->environ; *e != NULL; e++){
964
919
if(not add_environment(p, *e, false)){
965
error(0, errno, "add_environment");
920
perror("add_environment");
970
/* If this plugin has any environment variables, we need to
971
duplicate the environment from this process, too. */
925
/* If this plugin has any environment variables, we will call
926
using execve and need to duplicate the environment from this
972
928
if(p->environ[0] != NULL){
973
929
for(char **e = environ; *e != NULL; e++){
974
930
if(not add_environment(p, *e, false)){
975
error(0, errno, "add_environment");
931
perror("add_environment");
982
937
ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));
983
#else /* O_CLOEXEC */
984
ret = (int)TEMP_FAILURE_RETRY(pipe2(pipefd, O_CLOEXEC));
985
#endif /* O_CLOEXEC */
987
error(0, errno, "pipe");
988
exitstatus = EX_OSERR;
992
if(pipefd[0] >= FD_SETSIZE){
993
fprintf(stderr, "pipe()[0] (%d) >= FD_SETSIZE (%d)", pipefd[0],
997
exitstatus = EX_OSERR;
940
exitstatus = EXIT_FAILURE;
1002
943
/* Ask OS to automatic close the pipe on exec */
1003
944
ret = set_cloexec_flag(pipefd[0]);
1005
error(0, errno, "set_cloexec_flag");
1008
exitstatus = EX_OSERR;
1009
free(direntries[i]);
946
perror("set_cloexec_flag");
947
exitstatus = EXIT_FAILURE;
1012
950
ret = set_cloexec_flag(pipefd[1]);
1014
error(0, errno, "set_cloexec_flag");
1017
exitstatus = EX_OSERR;
1018
free(direntries[i]);
952
perror("set_cloexec_flag");
953
exitstatus = EXIT_FAILURE;
1021
#endif /* not O_CLOEXEC */
1022
956
/* Block SIGCHLD until process is safely in process list */
1023
957
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
1024
958
&sigchld_action.sa_mask,
1027
error(0, errno, "sigprocmask");
1028
exitstatus = EX_OSERR;
1029
free(direntries[i]);
961
perror("sigprocmask");
962
exitstatus = EXIT_FAILURE;
1032
965
/* Starting a new process to be watched */
1036
969
} while(pid == -1 and errno == EINTR);
1038
error(0, errno, "fork");
1039
TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,
1040
&sigchld_action.sa_mask, NULL));
1043
exitstatus = EX_OSERR;
1044
free(direntries[i]);
972
exitstatus = EXIT_FAILURE;
1048
976
/* this is the child process */
1049
977
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1051
error(0, errno, "sigaction");
1054
982
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1056
error(0, errno, "sigprocmask");
984
perror("sigprocmask");
1060
988
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1062
error(0, errno, "dup2");
1066
if(fexecve(plugin_fd, p->argv,
1067
(p->environ[0] != NULL) ? p->environ : environ) < 0){
1068
error(0, errno, "fexecve for %s/%s",
1069
plugindir != NULL ? plugindir : PDIR,
1070
direntries[i]->d_name);
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);
1073
1010
/* no return */
1075
1012
/* Parent process */
1076
close(pipefd[1]); /* Close unused write end of pipe */
1078
plugin *new_plugin = getplugin(direntries[i]->d_name);
1013
TEMP_FAILURE_RETRY(close(pipefd[1])); /* Close unused write end of
1016
plugin *new_plugin = getplugin(dirst->d_name);
1079
1017
if(new_plugin == NULL){
1080
error(0, errno, "getplugin");
1018
perror("getplugin");
1081
1019
ret = (int)(TEMP_FAILURE_RETRY
1082
1020
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
1085
error(0, errno, "sigprocmask");
1023
perror("sigprocmask");
1087
exitstatus = EX_OSERR;
1088
free(direntries[i]);
1025
exitstatus = EXIT_FAILURE;
1091
free(direntries[i]);
1093
1029
new_plugin->pid = pid;
1094
1030
new_plugin->fd = pipefd[0];
1202
1141
bool bret = print_out_password(proc->buffer,
1203
1142
proc->buffer_length);
1205
error(0, errno, "print_out_password");
1206
exitstatus = EX_IOERR;
1144
perror("print_out_password");
1145
exitstatus = EXIT_FAILURE;
1211
1150
/* This process has not completed. Does it have any output? */
1212
if(proc->eof or not FD_ISSET(proc->fd, &rfds)){
1151
if(proc->eof or not FD_ISSET(proc->fd, &rfds)){ /* Spurious
1213
1154
/* This process had nothing to say at this time */
1214
1155
proc = proc->next;
1217
1158
/* Before reading, make the process' data buffer large enough */
1218
1159
if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){
1219
char *new_buffer = realloc(proc->buffer, proc->buffer_size
1220
+ (size_t) BUFFER_SIZE);
1221
if(new_buffer == NULL){
1222
error(0, errno, "malloc");
1223
exitstatus = EX_OSERR;
1160
proc->buffer = realloc(proc->buffer, proc->buffer_size
1161
+ (size_t) BUFFER_SIZE);
1162
if(proc->buffer == NULL){
1164
exitstatus = EXIT_FAILURE;
1226
proc->buffer = new_buffer;
1227
1167
proc->buffer_size += BUFFER_SIZE;
1229
1169
/* Read from the process */