3
3
* Mandos plugin runner - Run Mandos plugins
5
* Copyright © 2008-2018 Teddy Hogeborn
6
* Copyright © 2008-2018 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
28
#include <stdlib.h> /* malloc(), exit(), EXIT_SUCCESS,
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
486
plugin *p = getplugin(arg);
514
488
p->disabled = false;
519
492
case 128: /* --plugin-dir */
521
494
plugindir = strdup(arg);
522
if(plugindir != NULL){
526
496
case 129: /* --config-file */
527
497
/* This is already done by parse_opt_config_file() */
529
499
case 130: /* --userid */
530
tmp_id = strtoimax(arg, &tmp, 10);
500
tmpmax = strtoimax(arg, &tmp, 10);
531
501
if(errno != 0 or tmp == arg or *tmp != '\0'
532
or tmp_id != (uid_t)tmp_id){
502
or tmpmax != (uid_t)tmpmax){
533
503
argp_error(state, "Bad user ID number: \"%s\", using %"
534
504
PRIdMAX, arg, (intmax_t)uid);
540
509
case 131: /* --groupid */
541
tmp_id = strtoimax(arg, &tmp, 10);
510
tmpmax = strtoimax(arg, &tmp, 10);
542
511
if(errno != 0 or tmp == arg or *tmp != '\0'
543
or tmp_id != (gid_t)tmp_id){
512
or tmpmax != (gid_t)tmpmax){
544
513
argp_error(state, "Bad group ID number: \"%s\", using %"
545
514
PRIdMAX, arg, (intmax_t)gid);
551
519
case 132: /* --debug */
554
case 133: /* --plugin-helper-dir */
555
free(pluginhelperdir);
556
pluginhelperdir = strdup(arg);
557
if(pluginhelperdir != NULL){
562
523
* These reproduce what we would get without ARGP_NO_HELP
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 */
743
/* Strip permissions down to nobody */
837
error(0, errno, "setgid");
839
748
ret = setuid(uid);
841
error(0, errno, "setuid");
844
753
/* Open plugin directory with close_on_exec flag */
846
dir_fd = open(plugindir != NULL ? plugindir : PDIR, O_RDONLY |
849
#else /* not O_CLOEXEC */
851
#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 */
853
773
if(dir_fd == -1){
854
error(0, errno, "Could not open plugin dir");
774
perror("Could not open plugin dir");
855
775
exitstatus = EX_UNAVAILABLE;
860
780
/* Set the FD_CLOEXEC flag on the directory */
861
781
ret = set_cloexec_flag(dir_fd);
863
error(0, errno, "set_cloexec_flag");
783
perror("set_cloexec_flag");
784
TEMP_FAILURE_RETRY(close(dir_fd));
864
785
exitstatus = EX_OSERR;
867
788
#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);
790
dir = fdopendir(dir_fd);
792
perror("Could not open plugin dir");
793
TEMP_FAILURE_RETRY(close(dir_fd));
794
exitstatus = EX_OSERR;
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
799
FD_ZERO(&rfds_all);
906
801
/* 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");
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",
915
ret = (int)TEMP_FAILURE_RETRY(fstat(plugin_fd, &st));
877
ret = (int)TEMP_FAILURE_RETRY(stat(filename, &st));
917
error(0, errno, "stat");
923
884
/* Ignore non-executable files */
924
885
if(not S_ISREG(st.st_mode)
925
or (TEMP_FAILURE_RETRY(faccessat(dir_fd, direntries[i]->d_name,
886
or (TEMP_FAILURE_RETRY(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);
888
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
889
" with bad type or mode\n", filename);
938
plugin *p = getplugin(direntries[i]->d_name);
895
plugin *p = getplugin(dirst->d_name);
940
error(0, errno, "getplugin");
947
903
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
948
direntries[i]->d_name);
958
913
for(char **a = g->argv + 1; *a != NULL; a++){
959
914
if(not add_argument(p, *a)){
960
error(0, errno, "add_argument");
915
perror("add_argument");
963
918
/* Add global environment variables */
964
919
for(char **e = g->environ; *e != NULL; e++){
965
920
if(not add_environment(p, *e, false)){
966
error(0, errno, "add_environment");
921
perror("add_environment");
971
/* If this plugin has any environment variables, we need to
972
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
973
929
if(p->environ[0] != NULL){
974
930
for(char **e = environ; *e != NULL; e++){
975
931
if(not add_environment(p, *e, false)){
976
error(0, errno, "add_environment");
932
perror("add_environment");
983
938
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;
941
exitstatus = EX_OSERR;
1003
944
/* Ask OS to automatic close the pipe on exec */
1004
945
ret = set_cloexec_flag(pipefd[0]);
1006
error(0, errno, "set_cloexec_flag");
947
perror("set_cloexec_flag");
1009
948
exitstatus = EX_OSERR;
1010
free(direntries[i]);
1013
951
ret = set_cloexec_flag(pipefd[1]);
1015
error(0, errno, "set_cloexec_flag");
953
perror("set_cloexec_flag");
1018
954
exitstatus = EX_OSERR;
1019
free(direntries[i]);
1022
#endif /* not O_CLOEXEC */
1023
957
/* Block SIGCHLD until process is safely in process list */
1024
958
ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,
1025
959
&sigchld_action.sa_mask,
1028
error(0, errno, "sigprocmask");
962
perror("sigprocmask");
1029
963
exitstatus = EX_OSERR;
1030
free(direntries[i]);
1033
966
/* Starting a new process to be watched */
1037
970
} 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
973
exitstatus = EX_OSERR;
1045
free(direntries[i]);
1049
977
/* this is the child process */
1050
978
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
1052
error(0, errno, "sigaction");
1053
981
_exit(EX_OSERR);
1055
983
ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
1057
error(0, errno, "sigprocmask");
985
perror("sigprocmask");
1058
986
_exit(EX_OSERR);
1061
989
ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
1063
error(0, errno, "dup2");
1064
992
_exit(EX_OSERR);
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);
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){
1074
1011
/* no return */
1076
1013
/* Parent process */
1077
close(pipefd[1]); /* Close unused write end of pipe */
1079
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);
1080
1018
if(new_plugin == NULL){
1081
error(0, errno, "getplugin");
1019
perror("getplugin");
1082
1020
ret = (int)(TEMP_FAILURE_RETRY
1083
1021
(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,
1086
error(0, errno, "sigprocmask");
1024
perror("sigprocmask");
1088
1026
exitstatus = EX_OSERR;
1089
free(direntries[i]);
1092
free(direntries[i]);
1094
1030
new_plugin->pid = pid;
1095
1031
new_plugin->fd = pipefd[0];