18
18
* along with this program. If not, see
19
19
* <http://www.gnu.org/licenses/>.
21
* Contact the authors at <https://www.fukt.bsnet.se/~belorn/> and
22
* <https://www.fukt.bsnet.se/~teddy/>.
21
* Contact the authors at <mandos@fukt.bsnet.se>.
25
#define _FORTIFY_SOURCE 2
24
#define _GNU_SOURCE /* TEMP_FAILURE_RETRY() */
27
#include <stdio.h> /* popen, fileno */
28
#include <iso646.h> /* and, or, not */
29
#include <sys/types.h> /* DIR, opendir, stat, struct stat, waitpid,
30
WIFEXITED, WEXITSTATUS, wait */
31
#include <sys/wait.h> /* wait */
32
#include <dirent.h> /* DIR, opendir */
33
#include <sys/stat.h> /* stat, struct stat */
34
#include <unistd.h> /* stat, struct stat, chdir */
35
#include <stdlib.h> /* EXIT_FAILURE */
36
#include <sys/select.h> /* fd_set, select, FD_ZERO, FD_SET,
38
#include <string.h> /* strlen, strcpy, strcat */
39
#include <stdbool.h> /* true */
40
#include <sys/wait.h> /* waitpid, WIFEXITED, WEXITSTATUS */
41
#include <errno.h> /* errno */
42
#include <argp.h> /* argp */
26
#include <stdio.h> /* popen(), fileno(), fprintf(),
27
stderr, STDOUT_FILENO */
28
#include <iso646.h> /* and, or, not */
29
#include <sys/types.h> /* DIR, opendir(), stat(),
30
struct stat, waitpid(),
31
WIFEXITED(), WEXITSTATUS(),
33
#include <sys/wait.h> /* wait() */
34
#include <dirent.h> /* DIR, struct dirent, opendir(),
35
readdir(), closedir() */
36
#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */
37
#include <unistd.h> /* struct stat, stat(), S_ISREG(),
39
#include <fcntl.h> /* fcntl() */
40
#include <stddef.h> /* NULL */
41
#include <stdlib.h> /* EXIT_FAILURE */
42
#include <sys/select.h> /* fd_set, select(), FD_ZERO(),
43
FD_SET(), FD_ISSET() */
44
#include <string.h> /* strlen(), strcpy(), strcat() */
45
#include <stdbool.h> /* true */
46
#include <sys/wait.h> /* waitpid(), WIFEXITED(),
48
#include <errno.h> /* errno */
49
#include <argp.h> /* struct argp_option,
50
struct argp_state, struct argp,
100
112
p->argv[p->argc] = NULL;
116
* Based on the example in the GNU LibC manual chapter 13.13 "File
118
* *Note File Descriptor Flags:(libc)Descriptor Flags.
120
int set_cloexec_flag(int fd)
122
int ret = fcntl(fd, F_GETFD, 0);
123
/* If reading the flags failed, return error indication now. */
127
/* Store modified flag word in the descriptor. */
128
return fcntl(fd, F_SETFD, ret | FD_CLOEXEC);
103
131
#define BUFFER_SIZE 256
105
const char *argp_program_version =
106
"plugbasedclient 0.9";
107
const char *argp_program_bug_address =
108
"<mandos@fukt.bsnet.se>";
110
"Mandos plugin runner -- Run Mandos plugins";
111
/* A description of the arguments we accept. */
112
static char args_doc[] = "";
133
const char *argp_program_version = "plugbasedclient 0.9";
134
const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";
136
process *process_list = NULL;
138
/* Mark a process as completed when it exits, and save its exit
140
void handle_sigchld(__attribute__((unused)) int sig){
141
process *proc = process_list;
143
pid_t pid = wait(&status);
144
while(proc != NULL and proc->pid != pid){
148
/* Process not found in process list */
151
proc->status = status;
152
proc->completed = true;
114
155
int main(int argc, char *argv[]){
115
const char *plugindir = "plugins.d";
156
const char *plugindir = "/conf/conf.d/mandos/plugins.d";
116
157
size_t d_name_len;
118
159
struct dirent *dirst;
121
162
int ret, maxfd = 0;
122
process *process_list = NULL;
123
163
uid_t uid = 65534;
124
164
gid_t gid = 65534;
166
int exitstatus = EXIT_SUCCESS;
167
struct sigaction old_sigchld_action;
168
struct sigaction sigchld_action = { .sa_handler = handle_sigchld,
169
.sa_flags = SA_NOCLDSTOP };
171
/* Establish a signal handler */
172
sigemptyset(&sigchld_action.sa_mask);
173
ret = sigaddset(&sigchld_action.sa_mask, SIGCHLD);
178
ret = sigaction(SIGCHLD, &sigchld_action, &old_sigchld_action);
125
184
/* The options we understand. */
126
185
struct argp_option options[] = {
127
186
{ .name = "global-options", .key = 'g',
128
.arg = "option[,option[,...]]", .flags = 0,
129
.doc = "Options effecting all plugins" },
187
.arg = "OPTION[,OPTION[,...]]",
188
.doc = "Options passed to all plugins" },
130
189
{ .name = "options-for", .key = 'o',
131
.arg = "plugin:option[,option[,...]]", .flags = 0,
132
.doc = "Options effecting only specified plugins" },
133
{ .name = "disable-plugin", .key = 'd',
134
.arg = "Plugin[,Plugin[,...]]", .flags = 0,
135
.doc = "Option to disable specififed plugins" },
190
.arg = "PLUGIN:OPTION[,OPTION[,...]]",
191
.doc = "Options passed only to specified plugin" },
192
{ .name = "disable", .key = 'd',
194
.doc = "Disable a specific plugin", .group = 1 },
136
195
{ .name = "plugin-dir", .key = 128,
137
.arg = "Directory", .flags = 0,
138
.doc = "Option to change directory to search for plugins" },
197
.doc = "Specify a different plugin directory", .group = 2 },
139
198
{ .name = "userid", .key = 129,
140
.arg = "Id", .flags = 0,
141
.doc = "Option to change which user id the plugins will run as" },
199
.arg = "ID", .flags = 0,
200
.doc = "User ID the plugins will run as", .group = 2 },
142
201
{ .name = "groupid", .key = 130,
143
.arg = "Id", .flags = 0,
144
.doc = "Option to change which group id the plugins will run as" },
202
.arg = "ID", .flags = 0,
203
.doc = "Group ID the plugins will run as", .group = 2 },
204
{ .name = "debug", .key = 131,
205
.doc = "Debug mode", .group = 3 },
148
209
error_t parse_opt (int key, char *arg, struct argp_state *state) {
149
/* Get the INPUT argument from `argp_parse', which we
150
know is a pointer to our arguments structure. */
210
/* Get the INPUT argument from `argp_parse', which we know is a
211
pointer to our plugin list pointer. */
151
212
plugin **plugins = state->input;
154
215
if (arg != NULL){
155
216
char *p = strtok(arg, ",");
157
addarguments(getplugin(NULL, plugins), p);
218
addargument(getplugin(NULL, plugins), p);
158
219
p = strtok(NULL, ",");
245
322
d_name_len = strlen(dirst->d_name);
247
// Ignore dotfiles and backup files
248
if (dirst->d_name[0] == '.'
249
or dirst->d_name[d_name_len - 1] == '~'){
324
// Ignore dotfiles, backup files and other junk
326
bool bad_name = false;
328
const char const *bad_prefixes[] = { ".", "#", NULL };
330
const char const *bad_suffixes[] = { "~", "#", ".dpkg-new",
332
".dpkg-divert", NULL };
333
for(const char **pre = bad_prefixes; *pre != NULL; pre++){
334
size_t pre_len = strlen(*pre);
335
if((d_name_len >= pre_len)
336
and strncmp((dirst->d_name), *pre, pre_len) == 0){
338
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
339
" with bad prefix %s\n", dirst->d_name, *pre);
350
for(const char **suf = bad_suffixes; *suf != NULL; suf++){
351
size_t suf_len = strlen(*suf);
352
if((d_name_len >= suf_len)
353
and (strcmp((dirst->d_name)+d_name_len-suf_len, *suf)
356
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
357
" with bad suffix %s\n", dirst->d_name, *suf);
253
369
char *filename = malloc(d_name_len + strlen(plugindir) + 2);
254
strcpy(filename, plugindir);
255
strcat(filename, "/");
256
strcat(filename, dirst->d_name);
370
if (filename == NULL){
372
exitstatus = EXIT_FAILURE;
375
strcpy(filename, plugindir); /* Spurious warning */
376
strcat(filename, "/"); /* Spurious warning */
377
strcat(filename, dirst->d_name); /* Spurious warning */
258
379
stat(filename, &st);
260
if (S_ISREG(st.st_mode)
261
and (access(filename, X_OK) == 0)
262
and not (getplugin(dirst->d_name, &plugin_list)->disable)){
263
// Starting a new process to be watched
264
process *new_process = malloc(sizeof(process));
271
new_process->pid = fork();
272
if(new_process->pid == 0){
273
/* this is the child process */
381
if (not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){
383
fprintf(stderr, "Ignoring plugin dir entry \"%s\""
384
" with bad type or mode\n", filename);
389
if(getplugin(dirst->d_name, &plugin_list)->disabled){
391
fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",
397
plugin *p = getplugin(dirst->d_name, &plugin_list);
399
/* Add global arguments to argument list for this plugin */
400
plugin *g = getplugin(NULL, &plugin_list);
401
for(char **a = g->argv + 1; *a != NULL; a++){
409
exitstatus = EXIT_FAILURE;
412
ret = set_cloexec_flag(pipefd[0]);
414
perror("set_cloexec_flag");
415
exitstatus = EXIT_FAILURE;
418
ret = set_cloexec_flag(pipefd[1]);
420
perror("set_cloexec_flag");
421
exitstatus = EXIT_FAILURE;
424
/* Block SIGCHLD until process is safely in process list */
425
ret = sigprocmask (SIG_BLOCK, &sigchld_action.sa_mask, NULL);
427
perror("sigprocmask");
428
exitstatus = EXIT_FAILURE;
431
// Starting a new process to be watched
434
/* this is the child process */
435
ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);
440
ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
442
perror("sigprocmask");
445
dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
448
/* If dir has no file descriptor, we could not set FD_CLOEXEC
449
above and must now close it manually here. */
275
close(pipefd[0]); /* close unused read end of pipe */
276
dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */
278
plugin *p = getplugin(dirst->d_name, &plugin_list);
279
plugin *g = getplugin(NULL, &plugin_list);
280
for(char **a = g->argv + 1; *a != NULL; a++){
283
if(execv(filename, p->argv) < 0){
290
close(pipefd[1]); /* close unused write end of pipe */
291
new_process->fd = pipefd[0];
292
new_process->buffer = malloc(BUFFER_SIZE);
293
if (new_process->buffer == NULL){
297
new_process->buffer_size = BUFFER_SIZE;
298
new_process->buffer_length = 0;
299
FD_SET(new_process->fd, &rfds_orig);
301
if (maxfd < new_process->fd){
302
maxfd = new_process->fd;
306
new_process->next = process_list;
307
process_list = new_process;
452
if(execv(filename, p->argv) < 0){
460
close(pipefd[1]); /* close unused write end of pipe */
461
process *new_process = malloc(sizeof(process));
462
if (new_process == NULL){
464
ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
466
perror("sigprocmask");
468
exitstatus = EXIT_FAILURE;
472
*new_process = (struct process){ .pid = pid,
474
.next = process_list };
476
process_list = new_process;
477
/* Unblock SIGCHLD so signal handler can be run if this process
478
has already completed */
479
ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);
481
perror("sigprocmask");
482
exitstatus = EXIT_FAILURE;
486
FD_SET(new_process->fd, &rfds_all);
488
if (maxfd < new_process->fd){
489
maxfd = new_process->fd;
494
/* Free the plugin list */
495
for(plugin *next; plugin_list != NULL; plugin_list = next){
496
next = plugin_list->next;
497
free(plugin_list->argv);
313
if (process_list != NULL){
315
fd_set rfds = rfds_orig;
316
int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);
317
if (select_ret == -1){
321
for(process *process_itr = process_list; process_itr != NULL;
322
process_itr = process_itr->next){
323
if(FD_ISSET(process_itr->fd, &rfds)){
324
if(process_itr->buffer_length + BUFFER_SIZE
325
> process_itr->buffer_size){
326
process_itr->buffer = realloc(process_itr->buffer,
327
process_itr->buffer_size
328
+ (size_t) BUFFER_SIZE);
329
if (process_itr->buffer == NULL){
333
process_itr->buffer_size += BUFFER_SIZE;
335
ret = read(process_itr->fd, process_itr->buffer
336
+ process_itr->buffer_length, BUFFER_SIZE);
338
/* Read error from this process; ignore it */
341
process_itr->buffer_length += (size_t) ret;
344
/* wait for process exit */
346
waitpid(process_itr->pid, &status, 0);
347
if(WIFEXITED(status) and WEXITSTATUS(status) == 0){
348
for(size_t written = 0;
349
written < process_itr->buffer_length;){
350
ret = write(STDOUT_FILENO,
351
process_itr->buffer + written,
352
process_itr->buffer_length - written);
357
written += (size_t)ret;
361
FD_CLR(process_itr->fd, &rfds_orig);
504
if (process_list == NULL){
505
fprintf(stderr, "No plugin processes started, exiting\n");
506
exitstatus = EXIT_FAILURE;
510
fd_set rfds = rfds_all;
511
int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);
512
if (select_ret == -1){
514
exitstatus = EXIT_FAILURE;
517
/* OK, now either a process completed, or something can be read
519
for(process *proc = process_list; proc ; proc = proc->next){
520
/* Is this process completely done? */
521
if(proc->eof and proc->completed){
522
/* Only accept the plugin output if it exited cleanly */
523
if(not WIFEXITED(proc->status)
524
or WEXITSTATUS(proc->status) != 0){
525
/* Bad exit by plugin */
527
if(WIFEXITED(proc->status)){
528
fprintf(stderr, "Plugin %d exited with status %d\n",
529
proc->pid, WEXITSTATUS(proc->status));
530
} else if(WIFSIGNALED(proc->status)) {
531
fprintf(stderr, "Plugin %d killed by signal %d\n",
532
proc->pid, WTERMSIG(proc->status));
533
} else if(WCOREDUMP(proc->status)){
534
fprintf(stderr, "Plugin %d dumped core\n", proc->pid);
537
/* Remove the plugin */
538
FD_CLR(proc->fd, &rfds_all);
539
/* Block signal while modifying process_list */
540
ret = sigprocmask (SIG_BLOCK, &sigchld_action.sa_mask, NULL);
542
perror("sigprocmask");
543
exitstatus = EXIT_FAILURE;
546
/* Delete this process entry from the list */
547
if(process_list == proc){
548
/* First one - simple */
549
process_list = proc->next;
551
/* Second one or later */
552
for(process *p = process_list; p != NULL; p = p->next){
554
p->next = proc->next;
559
/* We are done modifying process list, so unblock signal */
560
ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask,
563
perror("sigprocmask");
567
/* We deleted this process from the list, so we can't go
568
proc->next. Therefore, start over from the beginning of
572
/* This process exited nicely, so print its buffer */
573
for(size_t written = 0; written < proc->buffer_length;
574
written += (size_t)ret){
575
ret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO,
576
proc->buffer + written,
581
exitstatus = EXIT_FAILURE;
587
/* This process has not completed. Does it have any output? */
588
if(proc->eof or not FD_ISSET(proc->fd, &rfds)){
589
/* This process had nothing to say at this time */
592
/* Before reading, make the process' data buffer large enough */
593
if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){
594
proc->buffer = realloc(proc->buffer, proc->buffer_size
595
+ (size_t) BUFFER_SIZE);
596
if (proc->buffer == NULL){
598
exitstatus = EXIT_FAILURE;
601
proc->buffer_size += BUFFER_SIZE;
603
/* Read from the process */
604
ret = read(proc->fd, proc->buffer + proc->buffer_length,
607
/* Read error from this process; ignore the error */
614
proc->buffer_length += (size_t) ret;
618
if(process_list == NULL){
619
fprintf(stderr, "All plugin processes failed, exiting\n");
620
exitstatus = EXIT_FAILURE;
371
for(process *process_itr = process_list; process_itr != NULL;
372
process_itr = process_itr->next){
373
close(process_itr->fd);
374
kill(process_itr->pid, SIGTERM);
375
free(process_itr->buffer);
624
/* Restore old signal handler */
625
sigaction(SIGCHLD, &old_sigchld_action, NULL);
627
/* Free the plugin list */
628
for(plugin *next; plugin_list != NULL; plugin_list = next){
629
next = plugin_list->next;
630
free(plugin_list->argv);
638
/* Free the process list and kill the processes */
639
for(process *next; process_list != NULL; process_list = next){
640
next = process_list->next;
641
close(process_list->fd);
642
kill(process_list->pid, SIGTERM);
643
free(process_list->buffer);
647
/* Wait for any remaining child processes to terminate */