/mandos/release : revision 68

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#define _GNU_SOURCE /* TEMP_FAILURE_RETRY() */

25

26

#include <stdio.h> /* popen(), fileno(), fprintf(),

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stderr, STDOUT_FILENO */

26

#include <stddef.h> /* size_t, NULL */

27

#include <stdlib.h> /* malloc(), exit(), EXIT_FAILURE,

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EXIT_SUCCESS, realloc() */

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#include <stdbool.h> /* bool, true, false */

30

#include <stdio.h> /* perror, popen(), fileno(),

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fprintf(), stderr, STDOUT_FILENO */

32

#include <sys/types.h> /* DIR, opendir(), stat(), struct

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stat, waitpid(), WIFEXITED(),

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WEXITSTATUS(), wait(), pid_t,

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uid_t, gid_t, getuid(), getgid(),

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dirfd() */

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#include <sys/select.h> /* fd_set, select(), FD_ZERO(),

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FD_SET(), FD_ISSET(), FD_CLR */

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#include <sys/wait.h> /* wait(), waitpid(), WIFEXITED(),

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WEXITSTATUS() */

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#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */

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42

#include <iso646.h> /* and, or, not */

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#include <sys/types.h> /* DIR, opendir(), stat(),

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struct stat, waitpid(),

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WIFEXITED(), WEXITSTATUS(),

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wait() */

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#include <sys/wait.h> /* wait() */

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43

#include <dirent.h> /* DIR, struct dirent, opendir(),

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readdir(), closedir() */

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#include <sys/stat.h> /* struct stat, stat(), S_ISREG() */

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readdir(), closedir(), dirfd() */

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#include <unistd.h> /* struct stat, stat(), S_ISREG(),

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fcntl() */

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#include <fcntl.h> /* fcntl() */

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#include <stddef.h> /* NULL */

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#include <stdlib.h> /* EXIT_FAILURE */

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#include <sys/select.h> /* fd_set, select(), FD_ZERO(),

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FD_SET(), FD_ISSET() */

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#include <string.h> /* strlen(), strcpy(), strcat() */

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#include <stdbool.h> /* true */

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#include <sys/wait.h> /* waitpid(), WIFEXITED(),

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WEXITSTATUS() */

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fcntl(), setuid(), setgid(),

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F_GETFD, F_SETFD, FD_CLOEXEC,

48

access(), pipe(), fork(), close()

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dup2, STDOUT_FILENO, _exit(),

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execv(), write(), read(),

51

close() */

52

#include <fcntl.h> /* fcntl(), F_GETFD, F_SETFD,

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FD_CLOEXEC */

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#include <string.h> /* strtok, strlen(), strcpy(),

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strcat() */

48

56

#include <errno.h> /* errno */

49

#include <argp.h> /* struct argp_option,

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struct argp_state, struct argp,

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argp_parse() */

57

#include <argp.h> /* struct argp_option, struct

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argp_state, struct argp,

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argp_parse(), ARGP_ERR_UNKNOWN,

60

ARGP_KEY_END, ARGP_KEY_ARG, error_t */

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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() */

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#include <errno.h> /* errno, EBADF */

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#define BUFFER_SIZE 256

68

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const char *argp_program_version = "mandos-client 1.0";

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const char *argp_program_bug_address = "<mandos@fukt.bsnet.se>";

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struct process;

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73

58

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char *buffer;

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size_t buffer_size;

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79

size_t buffer_length;

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bool eof;

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bool completed;

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int status;

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struct process *next;

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84

} process;

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85

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struct plugin *next;

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92

} plugin;

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93

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plugin *getplugin(char *name, plugin **plugin_list){

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static plugin *getplugin(char *name, plugin **plugin_list){

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for (plugin *p = *plugin_list; p != NULL; p = p->next){

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if ((p->name == name)

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or (p->name and name and (strcmp(p->name, name) == 0))){

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120

return new_plugin;

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121

}

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void addargument(plugin *p, char *arg){

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static void addargument(plugin *p, char *arg){

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124

p->argv[p->argc] = arg;

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p->argv = realloc(p->argv, sizeof(char *) * (size_t)(p->argc + 2));

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126

if (p->argv == NULL){

114

136

* Descriptor Flags".

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137

* *Note File Descriptor Flags:(libc)Descriptor Flags.

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138

*/

117

int set_cloexec_flag(int fd)

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static int set_cloexec_flag(int fd)

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{

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int ret = fcntl(fd, F_GETFD, 0);

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/* If reading the flags failed, return error indication now. */

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return fcntl(fd, F_SETFD, ret | FD_CLOEXEC);

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}

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#define BUFFER_SIZE 256

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const char *argp_program_version =

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"plugbasedclient 0.9";

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const char *argp_program_bug_address =

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"<mandos@fukt.bsnet.se>";

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process *process_list = NULL;

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/* Mark a process as completed when it exits, and save its exit

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status. */

154

void handle_sigchld(__attribute__((unused)) int sig){

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process *proc = process_list;

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int status;

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pid_t pid = wait(&status);

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if(pid == -1){

159

perror("wait");

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return;

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}

162

while(proc != NULL and proc->pid != pid){

163

proc = proc->next;

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}

165

if(proc == NULL){

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/* Process not found in process list */

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return;

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}

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proc->status = status;

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proc->completed = true;

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}

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bool print_out_password(const char *buffer, size_t length){

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ssize_t ret;

175

if(length>0 and buffer[length-1] == '\n'){

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length--;

177

}

178

for(size_t written = 0; written < length; written += (size_t)ret){

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ret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO, buffer + written,

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length - written));

181

if(ret < 0){

182

return false;

183

}

184

}

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return true;

186

}

135

187

136

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int main(int argc, char *argv[]){

137

189

const char *plugindir = "/conf/conf.d/mandos/plugins.d";

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190

size_t d_name_len;

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DIR *dir;

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DIR *dir = NULL;

140

192

struct dirent *dirst;

141

193

struct stat st;

142

194

fd_set rfds_all;

143

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int ret, maxfd = 0;

144

process *process_list = NULL;

196

uid_t uid = 65534;

197

gid_t gid = 65534;

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bool debug = false;

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199

int exitstatus = EXIT_SUCCESS;

200

struct sigaction old_sigchld_action;

201

struct sigaction sigchld_action = { .sa_handler = handle_sigchld,

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.sa_flags = SA_NOCLDSTOP };

203

char *plus_options = NULL;

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char **plus_argv = NULL;

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/* Establish a signal handler */

207

sigemptyset(&sigchld_action.sa_mask);

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ret = sigaddset(&sigchld_action.sa_mask, SIGCHLD);

209

if(ret < 0){

210

perror("sigaddset");

211

exit(EXIT_FAILURE);

212

}

213

ret = sigaction(SIGCHLD, &sigchld_action, &old_sigchld_action);

214

if(ret < 0){

215

perror("sigaction");

216

exit(EXIT_FAILURE);

217

}

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/* The options we understand. */

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struct argp_option options[] = {

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{ .name = "plugin-dir", .key = 128,

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.arg = "DIRECTORY",

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.doc = "Specify a different plugin directory", .group = 2 },

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{ .name = "debug", .key = 129,

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{ .name = "userid", .key = 129,

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.arg = "ID", .flags = 0,

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.doc = "User ID the plugins will run as", .group = 2 },

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{ .name = "groupid", .key = 130,

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.arg = "ID", .flags = 0,

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.doc = "Group ID the plugins will run as", .group = 2 },

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{ .name = "debug", .key = 131,

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.doc = "Debug mode", .group = 3 },

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{ .name = NULL }

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242

};

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error_t parse_opt (int key, char *arg, struct argp_state *state) {

168

/* Get the INPUT argument from `argp_parse', which we

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know is a pointer to our plugin list pointer. */

245

/* Get the INPUT argument from `argp_parse', which we know is a

246

pointer to our plugin list pointer. */

170

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plugin **plugins = state->input;

171

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switch (key) {

172

249

case 'g':

175

252

do{

176

253

addargument(getplugin(NULL, plugins), p);

177

254

p = strtok(NULL, ",");

178

} while (p);

255

} while (p != NULL);

179

256

}

180

257

break;

181

258

case 'o':

182

259

if (arg != NULL){

183

260

char *name = strtok(arg, ":");

184

261

char *p = strtok(NULL, ":");

185

if(p){

262

if(p != NULL){

186

263

p = strtok(p, ",");

187

264

do{

188

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addargument(getplugin(name, plugins), p);

189

266

p = strtok(NULL, ",");

190

} while (p);

267

} while (p != NULL);

191

268

}

192

269

}

193

270

break;

200

277

plugindir = arg;

201

278

break;

202

279

case 129:

280

uid = (uid_t)strtol(arg, NULL, 10);

281

break;

282

case 130:

283

gid = (gid_t)strtol(arg, NULL, 10);

284

break;

285

case 131:

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286

debug = true;

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287

break;

205

288

case ARGP_KEY_ARG:

206

argp_usage (state);

289

if(plus_options != NULL or arg == NULL or arg[0] != '+'){

290

argp_usage (state);

291

}

292

plus_options = arg;

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293

break;

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294

case ARGP_KEY_END:

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295

break;

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plugin *plugin_list = NULL;

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struct argp argp = { .options = options, .parser = parse_opt,

219

.args_doc = "",

305

.args_doc = "[+PLUS_SEPARATED_OPTIONS]",

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.doc = "Mandos plugin runner -- Run plugins" };

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307

222

argp_parse (&argp, argc, argv, 0, 0, &plugin_list);

308

ret = argp_parse (&argp, argc, argv, 0, 0, &plugin_list);

309

if (ret == ARGP_ERR_UNKNOWN){

310

fprintf(stderr, "Unknown error while parsing arguments\n");

311

exitstatus = EXIT_FAILURE;

312

goto end;

313

}

314

315

if(plus_options){

316

/* This is a mangled argument in the form of

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"+--option+--other-option=parameter+--yet-another-option", etc */

318

/* Make new argc and argv vars, and call argp_parse() again. */

319

plus_options++; /* skip the first '+' character */

320

const char delims[] = "+";

321

char *arg;

322

int new_argc = 1;

323

plus_argv = malloc(sizeof(char*) * 2);

324

if(plus_argv == NULL){

325

perror("malloc");

326

exitstatus = EXIT_FAILURE;

327

goto end;

328

}

329

plus_argv[0] = argv[0];

330

plus_argv[1] = NULL;

331

arg = strtok(plus_options, delims); /* Get first argument */

332

while(arg != NULL){

333

new_argc++;

334

plus_argv = realloc(plus_argv, sizeof(char *)

335

* ((unsigned int) new_argc + 1));

336

if(plus_argv == NULL){

337

perror("realloc");

338

exitstatus = EXIT_FAILURE;

339

goto end;

340

}

341

plus_argv[new_argc-1] = arg;

342

plus_argv[new_argc] = NULL;

343

arg = strtok(NULL, delims); /* Get next argument */

344

}

345

ret = argp_parse (&argp, new_argc, plus_argv, 0, 0, &plugin_list);

346

if (ret == ARGP_ERR_UNKNOWN){

347

fprintf(stderr, "Unknown error while parsing arguments\n");

348

exitstatus = EXIT_FAILURE;

349

goto end;

350

}

351

}

223

352

224

353

if(debug){

225

354

for(plugin *p = plugin_list; p != NULL; p=p->next){

231

360

}

232

361

}

233

362

363

ret = setuid(uid);

364

if (ret == -1){

365

perror("setuid");

366

}

367

368

setgid(gid);

369

if (ret == -1){

370

perror("setgid");

371

}

372

234

373

dir = opendir(plugindir);

235

374

if(dir == NULL){

236

375

perror("Could not open plugin dir");

237

376

exitstatus = EXIT_FAILURE;

238

377

goto end;

239

378

}

379

240

380

/* Set the FD_CLOEXEC flag on the directory, if possible */

241

381

{

242

382

int dir_fd = dirfd(dir);

250

390

}

251

391

}

252

392

253

if(dir == NULL){

254

fprintf(stderr, "Can not open directory\n");

255

return EXIT_FAILURE;

256

}

257

258

393

FD_ZERO(&rfds_all);

259

394

260

395

while(true){

262

397

263

398

// All directory entries have been processed

264

399

if(dirst == NULL){

400

if (errno == EBADF){

401

perror("readdir");

402

exitstatus = EXIT_FAILURE;

403

goto end;

404

}

265

405

break;

266

406

}

267

407

318

458

exitstatus = EXIT_FAILURE;

319

459

goto end;

320

460

}

321

strcpy(filename, plugindir);

322

strcat(filename, "/");

323

strcat(filename, dirst->d_name);

324

325

stat(filename, &st);

326

461

strcpy(filename, plugindir); /* Spurious warning */

462

strcat(filename, "/"); /* Spurious warning */

463

strcat(filename, dirst->d_name); /* Spurious warning */

464

465

ret = stat(filename, &st);

466

if (ret == -1){

467

perror("stat");

468

exitstatus = EXIT_FAILURE;

469

goto end;

470

}

471

327

472

if (not S_ISREG(st.st_mode) or (access(filename, X_OK) != 0)){

328

473

if(debug){

329

474

fprintf(stderr, "Ignoring plugin dir entry \"%s\""

330

475

" with bad type or mode\n", filename);

331

476

}

477

free(filename);

332

478

continue;

333

479

}

334

480

if(getplugin(dirst->d_name, &plugin_list)->disabled){

336

482

fprintf(stderr, "Ignoring disabled plugin \"%s\"\n",

337

483

dirst->d_name);

338

484

}

485

free(filename);

339

486

continue;

340

487

}

341

488

plugin *p = getplugin(dirst->d_name, &plugin_list);

365

512

exitstatus = EXIT_FAILURE;

366

513

goto end;

367

514

}

515

/* Block SIGCHLD until process is safely in process list */

516

ret = sigprocmask (SIG_BLOCK, &sigchld_action.sa_mask, NULL);

517

if(ret < 0){

518

perror("sigprocmask");

519

exitstatus = EXIT_FAILURE;

520

goto end;

521

}

368

522

// Starting a new process to be watched

369

523

pid_t pid = fork();

370

524

if(pid == 0){

371

525

/* this is the child process */

372

dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */

526

ret = sigaction(SIGCHLD, &old_sigchld_action, NULL);

527

if(ret < 0){

528

perror("sigaction");

529

_exit(EXIT_FAILURE);

530

}

531

ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);

532

if(ret < 0){

533

perror("sigprocmask");

534

_exit(EXIT_FAILURE);

535

}

536

537

ret = dup2(pipefd[1], STDOUT_FILENO); /* replace our stdout */

538

if(ret == -1){

539

perror("dup2");

540

_exit(EXIT_FAILURE);

541

}

373

542

374

543

if(dirfd(dir) < 0){

375

544

/* If dir has no file descriptor, we could not set FD_CLOEXEC

376

and must close it manually */

545

above and must now close it manually here. */

377

546

closedir(dir);

378

547

}

379

548

if(execv(filename, p->argv) < 0){

383

552

/* no return */

384

553

}

385

554

/* parent process */

555

free(filename);

386

556

close(pipefd[1]); /* close unused write end of pipe */

387

557

process *new_process = malloc(sizeof(process));

388

558

if (new_process == NULL){

389

559

perror("malloc");

560

ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);

561

if(ret < 0){

562

perror("sigprocmask");

563

}

390

564

exitstatus = EXIT_FAILURE;

391

565

goto end;

392

566

}

394

568

*new_process = (struct process){ .pid = pid,

395

569

.fd = pipefd[0],

396

570

.next = process_list };

571

// List handling

572

process_list = new_process;

573

/* Unblock SIGCHLD so signal handler can be run if this process

574

has already completed */

575

ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask, NULL);

576

if(ret < 0){

577

perror("sigprocmask");

578

exitstatus = EXIT_FAILURE;

579

goto end;

580

}

581

397

582

FD_SET(new_process->fd, &rfds_all);

398

583

399

584

if (maxfd < new_process->fd){

400

585

maxfd = new_process->fd;

401

586

}

402

587

403

//List handling

404

process_list = new_process;

405

588

}

406

589

407

590

/* Free the plugin list */

412

595

}

413

596

414

597

closedir(dir);

415

598

dir = NULL;

599

416

600

if (process_list == NULL){

417

fprintf(stderr, "No plugin processes started, exiting\n");

418

return EXIT_FAILURE;

601

fprintf(stderr, "No plugin processes started. Incorrect plugin"

602

" directory?\n");

603

process_list = NULL;

419

604

}

420

while(true){

605

while(process_list){

421

606

fd_set rfds = rfds_all;

422

607

int select_ret = select(maxfd+1, &rfds, NULL, NULL, NULL);

423

608

if (select_ret == -1){

425

610

exitstatus = EXIT_FAILURE;

426

611

goto end;

427

612

}

613

/* OK, now either a process completed, or something can be read

614

from one of them */

428

615

for(process *proc = process_list; proc ; proc = proc->next){

429

if(not FD_ISSET(proc->fd, &rfds)){

616

/* Is this process completely done? */

617

if(proc->eof and proc->completed){

618

/* Only accept the plugin output if it exited cleanly */

619

if(not WIFEXITED(proc->status)

620

or WEXITSTATUS(proc->status) != 0){

621

/* Bad exit by plugin */

622

if(debug){

623

if(WIFEXITED(proc->status)){

624

fprintf(stderr, "Plugin %u exited with status %d\n",

625

(unsigned int) (proc->pid),

626

WEXITSTATUS(proc->status));

627

} else if(WIFSIGNALED(proc->status)) {

628

fprintf(stderr, "Plugin %u killed by signal %d\n",

629

(unsigned int) (proc->pid),

630

WTERMSIG(proc->status));

631

} else if(WCOREDUMP(proc->status)){

632

fprintf(stderr, "Plugin %d dumped core\n",

633

(unsigned int) (proc->pid));

634

}

635

}

636

/* Remove the plugin */

637

FD_CLR(proc->fd, &rfds_all);

638

/* Block signal while modifying process_list */

639

ret = sigprocmask (SIG_BLOCK, &sigchld_action.sa_mask, NULL);

640

if(ret < 0){

641

perror("sigprocmask");

642

exitstatus = EXIT_FAILURE;

643

goto end;

644

}

645

/* Delete this process entry from the list */

646

if(process_list == proc){

647

/* First one - simple */

648

process_list = proc->next;

649

} else {

650

/* Second one or later */

651

for(process *p = process_list; p != NULL; p = p->next){

652

if(p->next == proc){

653

p->next = proc->next;

654

break;

655

}

656

}

657

}

658

/* We are done modifying process list, so unblock signal */

659

ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask,

660

NULL);

661

if(ret < 0){

662

perror("sigprocmask");

663

}

664

free(proc->buffer);

665

free(proc);

666

/* We deleted this process from the list, so we can't go

667

proc->next. Therefore, start over from the beginning of

668

the process list */

669

break;

670

}

671

/* This process exited nicely, so print its buffer */

672

673

bool bret = print_out_password(proc->buffer, proc->buffer_length);

674

if(not bret){

675

perror("print_out_password");

676

exitstatus = EXIT_FAILURE;

677

}

678

goto end;

679

}

680

/* This process has not completed. Does it have any output? */

681

if(proc->eof or not FD_ISSET(proc->fd, &rfds)){

682

/* This process had nothing to say at this time */

430

683

continue;

431

684

}

685

/* Before reading, make the process' data buffer large enough */

432

686

if(proc->buffer_length + BUFFER_SIZE > proc->buffer_size){

433

687

proc->buffer = realloc(proc->buffer, proc->buffer_size

434

688

+ (size_t) BUFFER_SIZE);

439

693

}

440

694

proc->buffer_size += BUFFER_SIZE;

441

695

}

696

/* Read from the process */

442

697

ret = read(proc->fd, proc->buffer + proc->buffer_length,

443

698

BUFFER_SIZE);

444

699

if(ret < 0){

445

/* Read error from this process; ignore it */

700

/* Read error from this process; ignore the error */

446

701

continue;

447

702

}

448

proc->buffer_length += (size_t) ret;

449

703

if(ret == 0){

450

704

/* got EOF */

451

/* wait for process exit */

452

int status;

453

waitpid(proc->pid, &status, 0);

454

if(not WIFEXITED(status) or WEXITSTATUS(status) != 0){

455

FD_CLR(proc->fd, &rfds_all);

456

continue;

457

}

458

for(size_t written = 0;

459

written < proc->buffer_length; written += (size_t)ret){

460

ret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO,

461

proc->buffer + written,

462

proc->buffer_length

463

- written));

464

if(ret < 0){

465

perror("write");

466

exitstatus = EXIT_FAILURE;

467

goto end;

468

}

469

}

470

goto end;

705

proc->eof = true;

706

} else {

707

proc->buffer_length += (size_t) ret;

471

708

}

472

709

}

473

710

}

474

711

712

475

713

end:

714

715

if(process_list == NULL or exitstatus != EXIT_SUCCESS){

716

/* Fallback if all plugins failed or an error occured */

717

bool bret;

718

fprintf(stderr, "Going to fallback mode using getpass(3)\n");

719

char *passwordbuffer = getpass("Password: ");

720

bret = print_out_password(passwordbuffer, strlen(passwordbuffer));

721

if(not bret){

722

perror("print_out_password");

723

exitstatus = EXIT_FAILURE;

724

goto end;

725

}

726

}

727

728

/* Restore old signal handler */

729

sigaction(SIGCHLD, &old_sigchld_action, NULL);

730

731

free(plus_argv);

732

733

/* Free the plugin list */

734

for(plugin *next; plugin_list != NULL; plugin_list = next){

735

next = plugin_list->next;

736

free(plugin_list->argv);

737

free(plugin_list);

738

}

739

740

if(dir != NULL){

741

closedir(dir);

742

}

743

744

/* Free the process list and kill the processes */

476

745

for(process *next; process_list != NULL; process_list = next){

746

next = process_list->next;

477

747

close(process_list->fd);

478

kill(process_list->pid, SIGTERM);

748

ret = kill(process_list->pid, SIGTERM);

749

if(ret == -1 and errno != ESRCH){

750

/* set-uid proccesses migth not get closed */

751

perror("kill");

752

}

479

753

free(process_list->buffer);

480

754

free(process_list);

481

755

}

482

756

483

while(true){

484

int status;

485

ret = wait(&status);

486

if (ret == -1){

487

if(errno != ECHILD){

488

perror("wait");

489

}

490

break;

491

}

492

}

757

/* Wait for any remaining child processes to terminate */

758

do{

759

ret = wait(NULL);

760

} while(ret >= 0);

761

if(errno != ECHILD){

762

perror("wait");

763

}

764

493

765

return exitstatus;

494

766

}