/mandos/trunk : revision 375

1

/* -*- coding: utf-8 -*- */

1

/* -*- coding: utf-8; mode: c; mode: orgtbl -*- */

2

/*

3

* Mandos plugin runner - Run Mandos plugins

4

*

38

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

39

FD_SET(), FD_ISSET(), FD_CLR */

40

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

41

WEXITSTATUS() */

41

WEXITSTATUS(), WTERMSIG(),

42

WCOREDUMP() */

42

43

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

43

44

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

44

45

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

52

53

close() */

53

54

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

54

55

FD_CLOEXEC */

55

#include <string.h> /* strsep, strlen(), asprintf() */

56

#include <string.h> /* strsep, strlen(), asprintf(),

57

strsignal() */

56

58

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

57

59

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

58

60

argp_state, struct argp,

62

64

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

63

65

sigaddset(), sigaction(),

64

66

sigprocmask(), SIG_BLOCK, SIGCHLD,

65

SIG_UNBLOCK, kill() */

67

SIG_UNBLOCK, kill(), sig_atomic_t

68

*/

66

69

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

67

#include <inttypes.h> /* intmax_t, SCNdMAX, PRIdMAX, */

70

#include <inttypes.h> /* intmax_t, PRIdMAX, strtoimax() */

68

71

69

72

#define BUFFER_SIZE 256

70

73

81

84

char **environ;

82

85

int envc;

83

86

bool disabled;

84

87

85

88

/* Variables used for running processes*/

86

89

pid_t pid;

87

90

int fd;

89

92

size_t buffer_size;

90

93

size_t buffer_length;

91

94

bool eof;

92

volatile bool completed;

93

volatile int status;

95

volatile sig_atomic_t completed;

96

int status;

94

97

struct plugin *next;

95

98

} plugin;

96

99

107

110

}

108

111

}

109

112

/* Create a new plugin */

110

plugin *new_plugin = malloc(sizeof(plugin));

113

plugin *new_plugin = NULL;

114

do {

115

new_plugin = malloc(sizeof(plugin));

116

} while(new_plugin == NULL and errno == EINTR);

111

117

if(new_plugin == NULL){

112

118

return NULL;

113

119

}

114

120

char *copy_name = NULL;

115

121

if(name != NULL){

116

copy_name = strdup(name);

122

do {

123

copy_name = strdup(name);

124

} while(copy_name == NULL and errno == EINTR);

117

125

if(copy_name == NULL){

118

126

free(new_plugin);

119

127

return NULL;

120

128

}

121

129

}

122

130

123

*new_plugin = (plugin) { .name = copy_name,

124

.argc = 1,

125

.disabled = false,

126

.next = plugin_list };

131

*new_plugin = (plugin){ .name = copy_name,

132

.argc = 1,

133

.disabled = false,

134

.next = plugin_list };

127

135

128

new_plugin->argv = malloc(sizeof(char *) * 2);

136

do {

137

new_plugin->argv = malloc(sizeof(char *) * 2);

138

} while(new_plugin->argv == NULL and errno == EINTR);

129

139

if(new_plugin->argv == NULL){

130

140

free(copy_name);

131

141

free(new_plugin);

134

144

new_plugin->argv[0] = copy_name;

135

145

new_plugin->argv[1] = NULL;

136

146

137

new_plugin->environ = malloc(sizeof(char *));

147

do {

148

new_plugin->environ = malloc(sizeof(char *));

149

} while(new_plugin->environ == NULL and errno == EINTR);

138

150

if(new_plugin->environ == NULL){

139

151

free(copy_name);

140

152

free(new_plugin->argv);

152

164

static bool add_to_char_array(const char *new, char ***array,

153

165

int *len){

154

166

/* Resize the pointed-to array to hold one more pointer */

155

*array = realloc(*array, sizeof(char *)

156

* (size_t) ((*len) + 2));

167

do {

168

*array = realloc(*array, sizeof(char *)

169

* (size_t) ((*len) + 2));

170

} while(*array == NULL and errno == EINTR);

157

171

/* Malloc check */

158

172

if(*array == NULL){

159

173

return false;

160

174

}

161

175

/* Make a copy of the new string */

162

char *copy = strdup(new);

176

char *copy;

177

do {

178

copy = strdup(new);

179

} while(copy == NULL and errno == EINTR);

163

180

if(copy == NULL){

164

181

return false;

165

182

}

191

208

if(strncmp(*e, def, namelen + 1) == 0){

192

209

/* It already exists */

193

210

if(replace){

194

char *new = realloc(*e, strlen(def) + 1);

211

char *new;

212

do {

213

new = realloc(*e, strlen(def) + 1);

214

} while(new == NULL and errno == EINTR);

195

215

if(new == NULL){

196

216

return false;

197

217

}

207

227

/*

208

228

* Based on the example in the GNU LibC manual chapter 13.13 "File

209

229

* Descriptor Flags".

210

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

230

| [[info:libc:Descriptor%20Flags][File Descriptor Flags]] |

211

231

*/

212

232

static int set_cloexec_flag(int fd){

213

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

233

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

214

234

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

215

235

if(ret < 0){

216

236

return ret;

217

237

}

218

238

/* Store modified flag word in the descriptor. */

219

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

239

return (int)TEMP_FAILURE_RETRY(fcntl(fd, F_SETFD,

240

ret | FD_CLOEXEC));

220

241

}

221

242

222

243

223

244

/* Mark processes as completed when they exit, and save their exit

224

245

status. */

225

246

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

247

int old_errno = errno;

226

248

while(true){

227

249

plugin *proc = plugin_list;

228

250

int status;

232

254

break;

233

255

}

234

256

if(pid == -1){

235

if(errno != ECHILD){

236

perror("waitpid");

257

if(errno == ECHILD){

258

/* No child processes */

259

break;

237

260

}

238

/* No child processes */

239

break;

261

perror("waitpid");

240

262

}

241

263

242

264

/* A child exited, find it in process_list */

248

270

continue;

249

271

}

250

272

proc->status = status;

251

proc->completed = true;

273

proc->completed = 1;

252

274

}

275

errno = old_errno;

253

276

}

254

277

255

278

/* Prints out a password to stdout */

277

300

}

278

301

free(plugin_node->environ);

279

302

free(plugin_node->buffer);

280

303

281

304

/* Removes the plugin from the singly-linked list */

282

305

if(plugin_node == plugin_list){

283

306

/* First one - simple */

310

333

struct dirent *dirst;

311

334

struct stat st;

312

335

fd_set rfds_all;

313

int ret, numchars, maxfd = 0;

336

int ret, maxfd = 0;

314

337

ssize_t sret;

315

intmax_t tmpmax;

316

338

uid_t uid = 65534;

317

339

gid_t gid = 65534;

318

340

bool debug = false;

376

398

};

377

399

378

400

error_t parse_opt(int key, char *arg, __attribute__((unused))

379

struct argp_state *state) {

380

switch(key) {

401

struct argp_state *state){

402

switch(key){

403

char *tmp;

404

intmax_t tmpmax;

381

405

case 'g': /* --global-options */

382

406

if(arg != NULL){

383

char *p;

384

while((p = strsep(&arg, ",")) != NULL){

385

if(p[0] == '\0'){

407

char *plugin_option;

408

while((plugin_option = strsep(&arg, ",")) != NULL){

409

if(plugin_option[0] == '\0'){

386

410

continue;

387

411

}

388

if(not add_argument(getplugin(NULL), p)){

412

if(not add_argument(getplugin(NULL), plugin_option)){

389

413

perror("add_argument");

390

414

return ARGP_ERR_UNKNOWN;

391

415

}

402

426

break;

403

427

case 'o': /* --options-for */

404

428

if(arg != NULL){

405

char *p_name = strsep(&arg, ":");

406

if(p_name[0] == '\0' or arg == NULL){

407

break;

408

}

409

char *opt = strsep(&arg, ":");

410

if(opt[0] == '\0' or opt == NULL){

411

break;

412

}

413

char *p;

414

while((p = strsep(&opt, ",")) != NULL){

415

if(p[0] == '\0'){

416

continue;

417

}

418

if(not add_argument(getplugin(p_name), p)){

429

char *plugin_name = strsep(&arg, ":");

430

if(plugin_name[0] == '\0'){

431

break;

432

}

433

char *plugin_option;

434

while((plugin_option = strsep(&arg, ",")) != NULL){

435

if(not add_argument(getplugin(plugin_name), plugin_option)){

419

436

perror("add_argument");

420

437

return ARGP_ERR_UNKNOWN;

421

438

}

460

477

plugindir = strdup(arg);

461

478

if(plugindir == NULL){

462

479

perror("strdup");

463

}

480

}

464

481

break;

465

482

case 129: /* --config-file */

466

483

/* This is already done by parse_opt_config_file() */

467

484

break;

468

485

case 130: /* --userid */

469

ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);

470

if(ret < 1 or tmpmax != (uid_t)tmpmax

471

or arg[numchars] != '\0'){

486

errno = 0;

487

tmpmax = strtoimax(arg, &tmp, 10);

488

if(errno != 0 or tmp == arg or *tmp != '\0'

489

or tmpmax != (uid_t)tmpmax){

472

490

fprintf(stderr, "Bad user ID number: \"%s\", using %"

473

491

PRIdMAX "\n", arg, (intmax_t)uid);

474

492

} else {

476

494

}

477

495

break;

478

496

case 131: /* --groupid */

479

ret = sscanf(arg, "%" SCNdMAX "%n", &tmpmax, &numchars);

480

if(ret < 1 or tmpmax != (gid_t)tmpmax

481

or arg[numchars] != '\0'){

497

errno = 0;

498

tmpmax = strtoimax(arg, &tmp, 10);

499

if(errno != 0 or tmp == arg or *tmp != '\0'

500

or tmpmax != (gid_t)tmpmax){

482

501

fprintf(stderr, "Bad group ID number: \"%s\", using %"

483

502

PRIdMAX "\n", arg, (intmax_t)gid);

484

503

} else {

512

531

ignores everything but the --config-file option. */

513

532

error_t parse_opt_config_file(int key, char *arg,

514

533

__attribute__((unused))

515

struct argp_state *state) {

516

switch(key) {

534

struct argp_state *state){

535

switch(key){

517

536

case 'g': /* --global-options */

518

537

case 'G': /* --global-env */

519

538

case 'o': /* --options-for */

528

547

if(argfile == NULL){

529

548

perror("strdup");

530

549

}

531

break;

550

break;

532

551

case 130: /* --userid */

533

552

case 131: /* --groupid */

534

553

case 132: /* --debug */

563

582

conffp = fopen(AFILE, "r");

564

583

} else {

565

584

conffp = fopen(argfile, "r");

566

}

585

}

567

586

if(conffp != NULL){

568

587

char *org_line = NULL;

569

588

char *p, *arg, *new_arg, *line;

570

589

size_t size = 0;

571

590

const char whitespace_delims[] = " \r\t\f\v\n";

572

591

const char comment_delim[] = "#";

573

592

574

593

custom_argc = 1;

575

594

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

576

595

if(custom_argv == NULL){

580

599

}

581

600

custom_argv[0] = argv[0];

582

601

custom_argv[1] = NULL;

583

602

584

603

/* for each line in the config file, strip whitespace and ignore

585

604

commented text */

586

605

while(true){

588

607

if(sret == -1){

589

608

break;

590

609

}

591

610

592

611

line = org_line;

593

612

arg = strsep(&line, comment_delim);

594

613

while((p = strsep(&arg, whitespace_delims)) != NULL){

613

632

goto fallback;

614

633

}

615

634

custom_argv[custom_argc-1] = new_arg;

616

custom_argv[custom_argc] = NULL;

635

custom_argv[custom_argc] = NULL;

617

636

}

618

637

}

638

do {

639

ret = fclose(conffp);

640

} while(ret == EOF and errno == EINTR);

641

if(ret == EOF){

642

perror("fclose");

643

exitstatus = EXIT_FAILURE;

644

goto fallback;

645

}

619

646

free(org_line);

620

647

} else {

621

648

/* Check for harmful errors and go to fallback. Other errors might

662

689

}

663

690

664

691

/* Strip permissions down to nobody */

692

setgid(gid);

693

if(ret == -1){

694

perror("setgid");

695

}

665

696

ret = setuid(uid);

666

697

if(ret == -1){

667

698

perror("setuid");

668

}

669

setgid(gid);

670

if(ret == -1){

671

perror("setgid");

672

699

}

673

700

674

701

if(plugindir == NULL){

700

727

701

728

/* Read and execute any executable in the plugin directory*/

702

729

while(true){

703

dirst = readdir(dir);

730

do {

731

dirst = readdir(dir);

732

} while(dirst == NULL and errno == EINTR);

704

733

705

734

/* All directory entries have been processed */

706

735

if(dirst == NULL){

757

786

continue;

758

787

}

759

788

}

760

789

761

790

char *filename;

762

791

if(plugindir == NULL){

763

ret = asprintf(&filename, PDIR "/%s", dirst->d_name);

792

ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, PDIR "/%s",

793

dirst->d_name));

764

794

} else {

765

ret = asprintf(&filename, "%s/%s", plugindir, dirst->d_name);

795

ret = (int)TEMP_FAILURE_RETRY(asprintf(&filename, "%s/%s",

796

plugindir,

797

dirst->d_name));

766

798

}

767

799

if(ret < 0){

768

800

perror("asprintf");

769

801

continue;

770

802

}

771

803

772

ret = stat(filename, &st);

804

ret = (int)TEMP_FAILURE_RETRY(stat(filename, &st));

773

805

if(ret == -1){

774

806

perror("stat");

775

807

free(filename);

776

808

continue;

777

809

}

778

810

779

811

/* Ignore non-executable files */

780

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

812

if(not S_ISREG(st.st_mode)

813

or (TEMP_FAILURE_RETRY(access(filename, X_OK)) != 0)){

781

814

if(debug){

782

815

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

783

816

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

829

862

}

830

863

831

864

int pipefd[2];

832

ret = pipe(pipefd);

865

ret = (int)TEMP_FAILURE_RETRY(pipe(pipefd));

833

866

if(ret == -1){

834

867

perror("pipe");

835

868

exitstatus = EXIT_FAILURE;

849

882

goto fallback;

850

883

}

851

884

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

852

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

885

ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,

886

&sigchld_action.sa_mask,

887

NULL));

853

888

if(ret < 0){

854

889

perror("sigprocmask");

855

890

exitstatus = EXIT_FAILURE;

856

891

goto fallback;

857

892

}

858

893

/* Starting a new process to be watched */

859

pid_t pid = fork();

894

pid_t pid;

895

do {

896

pid = fork();

897

} while(pid == -1 and errno == EINTR);

860

898

if(pid == -1){

861

899

perror("fork");

862

900

exitstatus = EXIT_FAILURE;

900

938

/* no return */

901

939

}

902

940

/* Parent process */

903

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

941

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

942

pipe */

904

943

free(filename);

905

944

plugin *new_plugin = getplugin(dirst->d_name);

906

945

if(new_plugin == NULL){

907

946

perror("getplugin");

908

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

947

ret = (int)(TEMP_FAILURE_RETRY

948

(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,

949

NULL)));

909

950

if(ret < 0){

910

951

perror("sigprocmask");

911

952

}

918

959

919

960

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

920

961

has already completed */

921

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

962

ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,

963

&sigchld_action.sa_mask,

964

NULL));

922

965

if(ret < 0){

923

966

perror("sigprocmask");

924

967

exitstatus = EXIT_FAILURE;

932

975

}

933

976

}

934

977

935

closedir(dir);

978

TEMP_FAILURE_RETRY(closedir(dir));

936

979

dir = NULL;

980

free_plugin(getplugin(NULL));

937

981

938

982

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

939

983

if(p->pid != 0){

950

994

while(plugin_list){

951

995

fd_set rfds = rfds_all;

952

996

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

953

if(select_ret == -1){

997

if(select_ret == -1 and errno != EINTR){

954

998

perror("select");

955

999

exitstatus = EXIT_FAILURE;

956

1000

goto fallback;

959

1003

from one of them */

960

1004

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

961

1005

/* Is this process completely done? */

962

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

1006

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

963

1007

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

964

1008

if(not WIFEXITED(proc->status)

965

1009

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

966

1010

/* Bad exit by plugin */

967

1011

968

1012

if(debug){

969

1013

if(WIFEXITED(proc->status)){

970

fprintf(stderr, "Plugin %" PRIdMAX " exited with status"

971

" %d\n", (intmax_t) (proc->pid),

1014

fprintf(stderr, "Plugin %s [%" PRIdMAX "] exited with"

1015

" status %d\n", proc->name,

1016

(intmax_t) (proc->pid),

972

1017

WEXITSTATUS(proc->status));

973

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

974

fprintf(stderr, "Plugin %" PRIdMAX " killed by signal"

975

" %d\n", (intmax_t) (proc->pid),

976

WTERMSIG(proc->status));

1018

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

1019

fprintf(stderr, "Plugin %s [%" PRIdMAX "] killed by"

1020

" signal %d: %s\n", proc->name,

1021

(intmax_t) (proc->pid),

1022

WTERMSIG(proc->status),

1023

strsignal(WTERMSIG(proc->status)));

977

1024

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

978

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

979

(intmax_t) (proc->pid));

1025

fprintf(stderr, "Plugin %s [%" PRIdMAX "] dumped"

1026

" core\n", proc->name, (intmax_t) (proc->pid));

980

1027

}

981

1028

}

982

1029

983

1030

/* Remove the plugin */

984

1031

FD_CLR(proc->fd, &rfds_all);

985

1032

986

1033

/* Block signal while modifying process_list */

987

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

1034

ret = (int)TEMP_FAILURE_RETRY(sigprocmask

1035

(SIG_BLOCK,

1036

&sigchld_action.sa_mask,

1037

NULL));

988

1038

if(ret < 0){

989

1039

perror("sigprocmask");

990

1040

exitstatus = EXIT_FAILURE;

996

1046

proc = next_plugin;

997

1047

998

1048

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

999

ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,

1000

NULL);

1049

ret = (int)(TEMP_FAILURE_RETRY

1050

(sigprocmask(SIG_UNBLOCK,

1051

&sigchld_action.sa_mask, NULL)));

1001

1052

if(ret < 0){

1002

1053

perror("sigprocmask");

1003

1054

exitstatus = EXIT_FAILURE;

1040

1091

proc->buffer_size += BUFFER_SIZE;

1041

1092

}

1042

1093

/* Read from the process */

1043

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

1044

BUFFER_SIZE);

1094

sret = TEMP_FAILURE_RETRY(read(proc->fd,

1095

proc->buffer

1096

+ proc->buffer_length,

1097

BUFFER_SIZE));

1045

1098

if(sret < 0){

1046

1099

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

1047

1100

proc = proc->next;

1055

1108

}

1056

1109

}

1057

1110

}

1058

1059

1111

1112

1060

1113

fallback:

1061

1114

1062

1115

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

1109

1162

}

1110

1163

1111

1164

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

1112

do{

1165

do {

1113

1166

ret = wait(NULL);

1114

1167

} while(ret >= 0);

1115

1168

if(errno != ECHILD){