/mandos/trunk : revision 24.1.38

23

24

#define _GNU_SOURCE /* TEMP_FAILURE_RETRY() */

25

26

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

27

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() */

29

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

30

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

31

fprintf(), stderr, STDOUT_FILENO */

32

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

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stat, waitpid(), WIFEXITED(),

34

WEXITSTATUS(), wait(), pid_t,

35

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

36

dirfd() */

37

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

38

FD_SET(), FD_ISSET(), FD_CLR */

39

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

40

WEXITSTATUS() */

41

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

28

42

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

29

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

30

struct stat, waitpid(),

31

WIFEXITED(), WEXITSTATUS(),

32

wait() */

33

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

34

43

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

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readdir(), closedir() */

36

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

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

37

45

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

38

fcntl() */

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(),

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WEXITSTATUS() */

46

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

47

F_GETFD, F_SETFD, FD_CLOEXEC,

48

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

49

dup2, STDOUT_FILENO, _exit(),

50

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

51

close() */

52

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

53

FD_CLOEXEC */

54

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

55

strcat() */

48

56

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

49

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

50

struct argp_state, struct argp,

51

argp_parse() */

57

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

58

argp_state, struct argp,

59

argp_parse(), ARGP_ERR_UNKNOWN,

60

ARGP_KEY_END, ARGP_KEY_ARG, error_t */

61

#include <signal.h> /* struct sigaction, sigemptyset(),

62

sigaddset(), sigaction(),

63

sigprocmask(), SIG_BLOCK, SIGCHLD,

64

SIG_UNBLOCK, kill() */

65

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

66

67

#define BUFFER_SIZE 256

68

69

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

70

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

52

71

53

72

struct process;

54

73

58

77

char *buffer;

59

78

size_t buffer_size;

60

79

size_t buffer_length;

80

bool eof;

81

bool completed;

82

int status;

61

83

struct process *next;

62

84

} process;

63

85

69

91

struct plugin *next;

70

92

} plugin;

71

93

72

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

94

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

73

95

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

74

96

if ((p->name == name)

75

97

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

98

120

return new_plugin;

99

121

}

100

122

101

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

123

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

102

124

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

103

125

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

104

126

if (p->argv == NULL){

114

136

* Descriptor Flags".

115

137

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

116

138

*/

117

int set_cloexec_flag(int fd)

139

static int set_cloexec_flag(int fd)

118

140

{

119

141

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

120

142

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

125

147

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

126

148

}

127

149

128

129

#define BUFFER_SIZE 256

130

131

const char *argp_program_version =

132

"plugbasedclient 0.9";

133

const char *argp_program_bug_address =

134

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

150

process *process_list = NULL;

151

152

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

153

status. */

154

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

155

process *proc = process_list;

156

int status;

157

pid_t pid = wait(&status);

158

if(pid == -1){

159

perror("wait");

160

return;

161

}

162

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

163

proc = proc->next;

164

}

165

if(proc == NULL){

166

/* Process not found in process list */

167

return;

168

}

169

proc->status = status;

170

proc->completed = true;

171

}

135

172

136

173

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

137

174

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

138

175

size_t d_name_len;

139

DIR *dir;

176

DIR *dir = NULL;

140

177

struct dirent *dirst;

141

178

struct stat st;

142

179

fd_set rfds_all;

143

180

int ret, maxfd = 0;

144

process *process_list = NULL;

181

uid_t uid = 65534;

182

gid_t gid = 65534;

145

183

bool debug = false;

146

184

int exitstatus = EXIT_SUCCESS;

185

struct sigaction old_sigchld_action;

186

struct sigaction sigchld_action = { .sa_handler = handle_sigchld,

187

.sa_flags = SA_NOCLDSTOP };

188

char *plus_options = NULL;

189

char **plus_argv = NULL;

190

191

/* Establish a signal handler */

192

sigemptyset(&sigchld_action.sa_mask);

193

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

194

if(ret < 0){

195

perror("sigaddset");

196

exit(EXIT_FAILURE);

197

}

198

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

199

if(ret < 0){

200

perror("sigaction");

201

exit(EXIT_FAILURE);

202

}

147

203

148

204

/* The options we understand. */

149

205

struct argp_option options[] = {

159

215

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

160

216

.arg = "DIRECTORY",

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

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

218

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

219

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

220

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

221

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

222

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

223

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

224

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

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225

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

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{ .name = NULL }

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227

};

166

228

167

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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

169

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

230

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

231

pointer to our plugin list pointer. */

170

232

plugin **plugins = state->input;

171

233

switch (key) {

172

234

case 'g':

175

237

do{

176

238

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

177

239

p = strtok(NULL, ",");

178

} while (p);

240

} while (p != NULL);

179

241

}

180

242

break;

181

243

case 'o':

182

244

if (arg != NULL){

183

245

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

184

246

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

185

if(p){

247

if(p != NULL){

186

248

p = strtok(p, ",");

187

249

do{

188

250

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

189

251

p = strtok(NULL, ",");

190

} while (p);

252

} while (p != NULL);

191

253

}

192

254

}

193

255

break;

200

262

plugindir = arg;

201

263

break;

202

264

case 129:

265

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

266

break;

267

case 130:

268

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

269

break;

270

case 131:

203

271

debug = true;

204

272

break;

205

273

case ARGP_KEY_ARG:

206

argp_usage (state);

274

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

275

argp_usage (state);

276

}

277

plus_options = arg;

207

278

break;

208

279

case ARGP_KEY_END:

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280

break;

216

287

plugin *plugin_list = NULL;

217

288

218

289

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

219

.args_doc = "",

290

.args_doc = "[+PLUS_SEPARATED_OPTIONS]",

220

291

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

221

292

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

293

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

294

if (ret == ARGP_ERR_UNKNOWN){

295

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

296

exitstatus = EXIT_FAILURE;

297

goto end;

298

}

299

300

if(plus_options){

301

/* This is a mangled argument in the form of

302

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

303

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

304

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

305

const char delims[] = "+";

306

char *arg;

307

int new_argc = 1;

308

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

309

if(plus_argv == NULL){

310

perror("malloc");

311

exitstatus = EXIT_FAILURE;

312

goto end;

313

}

314

plus_argv[0] = argv[0];

315

plus_argv[1] = NULL;

316

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

317

while(arg != NULL){

318

new_argc++;

319

plus_argv = realloc(plus_argv, sizeof(char *)

320

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

321

if(plus_argv == NULL){

322

perror("realloc");

323

exitstatus = EXIT_FAILURE;

324

goto end;

325

}

326

plus_argv[new_argc-1] = arg;

327

plus_argv[new_argc] = NULL;

328

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

329

}

330

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

331

if (ret == ARGP_ERR_UNKNOWN){

332

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

333

exitstatus = EXIT_FAILURE;

334

goto end;

335

}

336

}

223

337

224

338

if(debug){

225

339

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

231

345

}

232

346

}

233

347

348

ret = setuid(uid);

349

if (ret == -1){

350

perror("setuid");

351

}

352

353

setgid(gid);

354

if (ret == -1){

355

perror("setgid");

356

}

357

234

358

dir = opendir(plugindir);

235

359

if(dir == NULL){

236

360

perror("Could not open plugin dir");

237

361

exitstatus = EXIT_FAILURE;

238

362

goto end;

239

363

}

364

240

365

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

241

366

{

242

367

int dir_fd = dirfd(dir);

250

375

}

251

376

}

252

377

253

if(dir == NULL){

254

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

255

return EXIT_FAILURE;

256

}

257

258

378

FD_ZERO(&rfds_all);

259

379

260

380

while(true){

262

382

263

383

// All directory entries have been processed

264

384

if(dirst == NULL){

385

if (errno == EBADF){

386

perror("readdir");

387

exitstatus = EXIT_FAILURE;

388

goto end;

389

}

265

390

break;

266

391

}

267

392

318

443

exitstatus = EXIT_FAILURE;

319

444

goto end;

320

445

}

321

strcpy(filename, plugindir);

322

strcat(filename, "/");

323

strcat(filename, dirst->d_name);

324

325

stat(filename, &st);

326

446

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

447

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

448

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

449

450

ret = stat(filename, &st);

451

if (ret == -1){

452

perror("stat");

453

exitstatus = EXIT_FAILURE;

454

goto end;

455

}

456

327

457

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

328

458

if(debug){

329

459

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

330

460

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

331

461

}

462

free(filename);

332

463

continue;

333

464

}

334

465

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

336

467

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

337

468

dirst->d_name);

338

469

}

470

free(filename);

339

471

continue;

340

472

}

341

473

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

365

497

exitstatus = EXIT_FAILURE;

366

498

goto end;

367

499

}

500

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

501

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

502

if(ret < 0){

503

perror("sigprocmask");

504

exitstatus = EXIT_FAILURE;

505

goto end;

506

}

368

507

// Starting a new process to be watched

369

508

pid_t pid = fork();

370

509

if(pid == 0){

371

510

/* this is the child process */

372

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

511

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

512

if(ret < 0){

513

perror("sigaction");

514

_exit(EXIT_FAILURE);

515

}

516

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

517

if(ret < 0){

518

perror("sigprocmask");

519

_exit(EXIT_FAILURE);

520

}

521

522

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

523

if(ret == -1){

524

perror("dup2");

525

_exit(EXIT_FAILURE);

526

}

373

527

374

528

if(dirfd(dir) < 0){

375

529

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

376

and must close it manually */

530

above and must now close it manually here. */

377

531

closedir(dir);

378

532

}

379

533

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

383

537

/* no return */

384

538

}

385

539

/* parent process */

540

free(filename);

386

541

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

387

542

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

388

543

if (new_process == NULL){

389

544

perror("malloc");

545

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

546

if(ret < 0){

547

perror("sigprocmask");

548

}

390

549

exitstatus = EXIT_FAILURE;

391

550

goto end;

392

551

}

394

553

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

395

554

.fd = pipefd[0],

396

555

.next = process_list };

556

// List handling

557

process_list = new_process;

558

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

559

has already completed */

560

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

561

if(ret < 0){

562

perror("sigprocmask");

563

exitstatus = EXIT_FAILURE;

564

goto end;

565

}

566

397

567

FD_SET(new_process->fd, &rfds_all);

398

568

399

569

if (maxfd < new_process->fd){

400

570

maxfd = new_process->fd;

401

571

}

402

572

403

//List handling

404

process_list = new_process;

405

573

}

406

574

407

575

/* Free the plugin list */

412

580

}

413

581

414

582

closedir(dir);

415

583

dir = NULL;

584

416

585

if (process_list == NULL){

417

586

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

418

return EXIT_FAILURE;

587

exitstatus = EXIT_FAILURE;

588

goto end;

419

589

}

420

while(true){

590

while(process_list){

421

591

fd_set rfds = rfds_all;

422

592

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

423

593

if (select_ret == -1){

425

595

exitstatus = EXIT_FAILURE;

426

596

goto end;

427

597

}

598

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

599

from one of them */

428

600

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

429

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

601

/* Is this process completely done? */

602

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

603

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

604

if(not WIFEXITED(proc->status)

605

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

606

/* Bad exit by plugin */

607

if(debug){

608

if(WIFEXITED(proc->status)){

609

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

610

proc->pid, WEXITSTATUS(proc->status));

611

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

612

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

613

proc->pid, WTERMSIG(proc->status));

614

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

615

fprintf(stderr, "Plugin %d dumped core\n", proc->pid);

616

}

617

}

618

/* Remove the plugin */

619

FD_CLR(proc->fd, &rfds_all);

620

/* Block signal while modifying process_list */

621

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

622

if(ret < 0){

623

perror("sigprocmask");

624

exitstatus = EXIT_FAILURE;

625

goto end;

626

}

627

/* Delete this process entry from the list */

628

if(process_list == proc){

629

/* First one - simple */

630

process_list = proc->next;

631

} else {

632

/* Second one or later */

633

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

634

if(p->next == proc){

635

p->next = proc->next;

636

break;

637

}

638

}

639

}

640

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

641

ret = sigprocmask (SIG_UNBLOCK, &sigchld_action.sa_mask,

642

NULL);

643

if(ret < 0){

644

perror("sigprocmask");

645

}

646

free(proc->buffer);

647

free(proc);

648

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

649

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

650

the process list */

651

break;

652

}

653

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

654

for(size_t written = 0; written < proc->buffer_length;

655

written += (size_t)ret){

656

ret = TEMP_FAILURE_RETRY(write(STDOUT_FILENO,

657

proc->buffer + written,

658

proc->buffer_length

659

- written));

660

if(ret < 0){

661

perror("write");

662

exitstatus = EXIT_FAILURE;

663

goto end;

664

}

665

}

666

goto end;

667

}

668

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

669

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

670

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

430

671

continue;

431

672

}

673

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

432

674

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

433

675

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

434

676

+ (size_t) BUFFER_SIZE);

439

681

}

440

682

proc->buffer_size += BUFFER_SIZE;

441

683

}

684

/* Read from the process */

442

685

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

443

686

BUFFER_SIZE);

444

687

if(ret < 0){

445

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

688

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

446

689

continue;

447

690

}

448

proc->buffer_length += (size_t) ret;

449

691

if(ret == 0){

450

692

/* 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;

693

proc->eof = true;

694

} else {

695

proc->buffer_length += (size_t) ret;

471

696

}

472

697

}

473

698

}

699

if(process_list == NULL){

700

fprintf(stderr, "All plugin processes failed, exiting\n");

701

exitstatus = EXIT_FAILURE;

702

}

474

703

475

704

end:

705

/* Restore old signal handler */

706

sigaction(SIGCHLD, &old_sigchld_action, NULL);

707

708

free(plus_argv);

709

710

/* Free the plugin list */

711

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

712

next = plugin_list->next;

713

free(plugin_list->argv);

714

free(plugin_list);

715

}

716

717

if(dir != NULL){

718

closedir(dir);

719

}

720

721

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

476

722

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

723

next = process_list->next;

477

724

close(process_list->fd);

478

kill(process_list->pid, SIGTERM);

725

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

726

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

727

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

728

perror("kill");

729

}

479

730

free(process_list->buffer);

480

731

free(process_list);

481

732

}

482

733

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

}

734

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

735

do{

736

ret = wait(NULL);

737

} while(ret >= 0);

738

if(errno != ECHILD){

739

perror("wait");

740

}

741

493

742

return exitstatus;

494

743

}