/mandos/trunk : revision 287

1

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

1

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

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(), WTERMSIG(),

42

WCOREDUMP() */

41

WEXITSTATUS() */

43

42

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

44

43

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

45

44

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

53

52

close() */

54

53

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

55

54

FD_CLOEXEC */

56

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

57

strsignal() */

55

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

58

56

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

59

57

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

60

58

argp_state, struct argp,

64

62

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

65

63

sigaddset(), sigaction(),

66

64

sigprocmask(), SIG_BLOCK, SIGCHLD,

67

SIG_UNBLOCK, kill(), sig_atomic_t

68

*/

65

SIG_UNBLOCK, kill() */

69

66

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

70

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

67

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

71

68

72

69

#define BUFFER_SIZE 256

73

70

84

81

char **environ;

85

82

int envc;

86

83

bool disabled;

87

84

88

85

/* Variables used for running processes*/

89

86

pid_t pid;

90

87

int fd;

92

89

size_t buffer_size;

93

90

size_t buffer_length;

94

91

bool eof;

95

volatile sig_atomic_t completed;

96

int status;

92

volatile bool completed;

93

volatile int status;

97

94

struct plugin *next;

98

95

} plugin;

99

96

110

107

}

111

108

}

112

109

/* Create a new plugin */

113

plugin *new_plugin = NULL;

114

do {

115

new_plugin = malloc(sizeof(plugin));

116

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

110

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

117

111

if(new_plugin == NULL){

118

112

return NULL;

119

113

}

120

114

char *copy_name = NULL;

121

115

if(name != NULL){

122

do {

123

copy_name = strdup(name);

124

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

116

copy_name = strdup(name);

125

117

if(copy_name == NULL){

126

118

free(new_plugin);

127

119

return NULL;

128

120

}

129

121

}

130

122

131

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

132

.argc = 1,

133

.disabled = false,

134

.next = plugin_list };

123

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

124

.argc = 1,

125

.disabled = false,

126

.next = plugin_list };

135

127

136

do {

137

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

138

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

128

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

139

129

if(new_plugin->argv == NULL){

140

130

free(copy_name);

141

131

free(new_plugin);

144

134

new_plugin->argv[0] = copy_name;

145

135

new_plugin->argv[1] = NULL;

146

136

147

do {

148

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

149

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

137

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

150

138

if(new_plugin->environ == NULL){

151

139

free(copy_name);

152

140

free(new_plugin->argv);

164

152

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

165

153

int *len){

166

154

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

167

do {

168

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

169

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

170

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

155

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

156

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

171

157

/* Malloc check */

172

158

if(*array == NULL){

173

159

return false;

174

160

}

175

161

/* Make a copy of the new string */

176

char *copy;

177

do {

178

copy = strdup(new);

179

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

162

char *copy = strdup(new);

180

163

if(copy == NULL){

181

164

return false;

182

165

}

208

191

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

209

192

/* It already exists */

210

193

if(replace){

211

char *new;

212

do {

213

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

214

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

194

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

215

195

if(new == NULL){

216

196

return false;

217

197

}

227

207

/*

228

208

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

229

209

* Descriptor Flags".

230

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

210

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

231

211

*/

232

212

static int set_cloexec_flag(int fd){

233

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

213

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

234

214

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

235

215

if(ret < 0){

236

216

return ret;

237

217

}

238

218

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

239

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

219

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

240

220

}

241

221

242

222

243

223

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

244

224

status. */

245

225

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

246

int old_errno = errno;

247

226

while(true){

248

227

plugin *proc = plugin_list;

249

228

int status;

253

232

break;

254

233

}

255

234

if(pid == -1){

256

if(errno == ECHILD){

257

/* No child processes */

258

break;

235

if(errno != ECHILD){

236

perror("waitpid");

259

237

}

260

perror("waitpid");

238

/* No child processes */

239

break;

261

240

}

262

241

263

242

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

269

248

continue;

270

249

}

271

250

proc->status = status;

272

proc->completed = 1;

251

proc->completed = true;

273

252

}

274

errno = old_errno;

275

253

}

276

254

277

255

/* Prints out a password to stdout */

299

277

}

300

278

free(plugin_node->environ);

301

279

free(plugin_node->buffer);

302

280

303

281

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

304

282

if(plugin_node == plugin_list){

305

283

/* First one - simple */

332

310

struct dirent *dirst;

333

311

struct stat st;

334

312

fd_set rfds_all;

335

int ret, maxfd = 0;

313

int ret, numchars, maxfd = 0;

336

314

ssize_t sret;

315

intmax_t tmpmax;

337

316

uid_t uid = 65534;

338

317

gid_t gid = 65534;

339

318

bool debug = false;

397

376

};

398

377

399

378

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

400

struct argp_state *state){

401

switch(key){

402

char *tmp;

403

intmax_t tmpmax;

379

struct argp_state *state) {

380

switch(key) {

404

381

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

405

382

if(arg != NULL){

406

char *plugin_option;

407

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

408

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

383

char *p;

384

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

385

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

409

386

continue;

410

387

}

411

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

388

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

412

389

perror("add_argument");

413

390

return ARGP_ERR_UNKNOWN;

414

391

}

425

402

break;

426

403

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

427

404

if(arg != NULL){

428

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

429

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

430

break;

431

}

432

char *plugin_option;

433

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

434

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

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)){

435

419

perror("add_argument");

436

420

return ARGP_ERR_UNKNOWN;

437

421

}

476

460

plugindir = strdup(arg);

477

461

if(plugindir == NULL){

478

462

perror("strdup");

479

}

463

}

480

464

break;

481

465

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

482

466

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

483

467

break;

484

468

case 130: /* --userid */

485

errno = 0;

486

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

487

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

488

or tmpmax != (uid_t)tmpmax){

469

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

470

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

471

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

489

472

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

490

473

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

491

474

} else {

493

476

}

494

477

break;

495

478

case 131: /* --groupid */

496

errno = 0;

497

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

498

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

499

or tmpmax != (gid_t)tmpmax){

479

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

480

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

481

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

500

482

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

501

483

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

502

484

} else {

530

512

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

531

513

error_t parse_opt_config_file(int key, char *arg,

532

514

__attribute__((unused))

533

struct argp_state *state){

534

switch(key){

515

struct argp_state *state) {

516

switch(key) {

535

517

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

536

518

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

537

519

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

546

528

if(argfile == NULL){

547

529

perror("strdup");

548

530

}

549

break;

531

break;

550

532

case 130: /* --userid */

551

533

case 131: /* --groupid */

552

534

case 132: /* --debug */

581

563

conffp = fopen(AFILE, "r");

582

564

} else {

583

565

conffp = fopen(argfile, "r");

584

}

566

}

585

567

if(conffp != NULL){

586

568

char *org_line = NULL;

587

569

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

588

570

size_t size = 0;

589

571

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

590

572

const char comment_delim[] = "#";

591

573

592

574

custom_argc = 1;

593

575

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

594

576

if(custom_argv == NULL){

598

580

}

599

581

custom_argv[0] = argv[0];

600

582

custom_argv[1] = NULL;

601

583

602

584

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

603

585

commented text */

604

586

while(true){

606

588

if(sret == -1){

607

589

break;

608

590

}

609

591

610

592

line = org_line;

611

593

arg = strsep(&line, comment_delim);

612

594

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

631

613

goto fallback;

632

614

}

633

615

custom_argv[custom_argc-1] = new_arg;

634

custom_argv[custom_argc] = NULL;

616

custom_argv[custom_argc] = NULL;

635

617

}

636

618

}

637

do {

638

ret = fclose(conffp);

639

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

640

if(ret == EOF){

641

perror("fclose");

642

exitstatus = EXIT_FAILURE;

643

goto fallback;

644

}

645

619

free(org_line);

646

620

} else {

647

621

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

688

662

}

689

663

690

664

/* Strip permissions down to nobody */

665

ret = setuid(uid);

666

if(ret == -1){

667

perror("setuid");

668

}

691

669

setgid(gid);

692

670

if(ret == -1){

693

671

perror("setgid");

694

672

}

695

ret = setuid(uid);

696

if(ret == -1){

697

perror("setuid");

698

}

699

673

700

674

if(plugindir == NULL){

701

675

dir = opendir(PDIR);

726

700

727

701

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

728

702

while(true){

729

do {

730

dirst = readdir(dir);

731

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

703

dirst = readdir(dir);

732

704

733

705

/* All directory entries have been processed */

734

706

if(dirst == NULL){

785

757

continue;

786

758

}

787

759

}

788

760

789

761

char *filename;

790

762

if(plugindir == NULL){

791

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

792

dirst->d_name));

763

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

793

764

} else {

794

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

795

dirst->d_name));

765

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

796

766

}

797

767

if(ret < 0){

798

768

perror("asprintf");

799

769

continue;

800

770

}

801

771

802

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

772

ret = stat(filename, &st);

803

773

if(ret == -1){

804

774

perror("stat");

805

775

free(filename);

806

776

continue;

807

777

}

808

778

809

779

/* Ignore non-executable files */

810

if(not S_ISREG(st.st_mode)

811

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

780

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

812

781

if(debug){

813

782

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

814

783

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

860

829

}

861

830

862

831

int pipefd[2];

863

ret = TEMP_FAILURE_RETRY(pipe(pipefd));

832

ret = pipe(pipefd);

864

833

if(ret == -1){

865

834

perror("pipe");

866

835

exitstatus = EXIT_FAILURE;

880

849

goto fallback;

881

850

}

882

851

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

883

ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,

884

&sigchld_action.sa_mask,

885

NULL));

852

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

886

853

if(ret < 0){

887

854

perror("sigprocmask");

888

855

exitstatus = EXIT_FAILURE;

889

856

goto fallback;

890

857

}

891

858

/* Starting a new process to be watched */

892

pid_t pid;

893

do {

894

pid = fork();

895

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

859

pid_t pid = fork();

896

860

if(pid == -1){

897

861

perror("fork");

898

862

exitstatus = EXIT_FAILURE;

936

900

/* no return */

937

901

}

938

902

/* Parent process */

939

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

940

pipe */

903

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

941

904

free(filename);

942

905

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

943

906

if(new_plugin == NULL){

944

907

perror("getplugin");

945

ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,

946

&sigchld_action.sa_mask,

947

NULL));

908

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

948

909

if(ret < 0){

949

910

perror("sigprocmask");

950

911

}

957

918

958

919

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

959

920

has already completed */

960

ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,

961

&sigchld_action.sa_mask,

962

NULL));

921

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

963

922

if(ret < 0){

964

923

perror("sigprocmask");

965

924

exitstatus = EXIT_FAILURE;

973

932

}

974

933

}

975

934

976

TEMP_FAILURE_RETRY(closedir(dir));

935

closedir(dir);

977

936

dir = NULL;

978

free_plugin(getplugin(NULL));

979

937

980

938

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

981

939

if(p->pid != 0){

992

950

while(plugin_list){

993

951

fd_set rfds = rfds_all;

994

952

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

995

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

953

if(select_ret == -1){

996

954

perror("select");

997

955

exitstatus = EXIT_FAILURE;

998

956

goto fallback;

1001

959

from one of them */

1002

960

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

1003

961

/* Is this process completely done? */

1004

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

962

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

1005

963

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

1006

964

if(not WIFEXITED(proc->status)

1007

965

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

1008

966

/* Bad exit by plugin */

1009

967

1010

968

if(debug){

1011

969

if(WIFEXITED(proc->status)){

1012

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

1013

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

1014

(intmax_t) (proc->pid),

970

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

971

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

1015

972

WEXITSTATUS(proc->status));

1016

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

1017

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

1018

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

1019

(intmax_t) (proc->pid),

1020

WTERMSIG(proc->status),

1021

strsignal(WTERMSIG(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));

1022

977

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

1023

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

1024

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

978

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

979

(intmax_t) (proc->pid));

1025

980

}

1026

981

}

1027

982

1028

983

/* Remove the plugin */

1029

984

FD_CLR(proc->fd, &rfds_all);

1030

985

1031

986

/* Block signal while modifying process_list */

1032

ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,

1033

&sigchld_action.sa_mask,

1034

NULL));

987

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

1035

988

if(ret < 0){

1036

989

perror("sigprocmask");

1037

990

exitstatus = EXIT_FAILURE;

1043

996

proc = next_plugin;

1044

997

1045

998

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

1046

ret = TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,

1047

&sigchld_action.sa_mask,

1048

NULL));

999

ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,

1000

NULL);

1049

1001

if(ret < 0){

1050

1002

perror("sigprocmask");

1051

1003

exitstatus = EXIT_FAILURE;

1088

1040

proc->buffer_size += BUFFER_SIZE;

1089

1041

}

1090

1042

/* Read from the process */

1091

sret = TEMP_FAILURE_RETRY(read(proc->fd,

1092

proc->buffer

1093

+ proc->buffer_length,

1094

BUFFER_SIZE));

1043

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

1044

BUFFER_SIZE);

1095

1045

if(sret < 0){

1096

1046

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

1097

1047

proc = proc->next;

1105

1055

}

1106

1056

}

1107

1057

}

1108

1109

1058

1059

1110

1060

fallback:

1111

1061

1112

1062

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

1159

1109

}

1160

1110

1161

1111

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

1162

do {

1112

do{

1163

1113

ret = wait(NULL);

1164

1114

} while(ret >= 0);

1165

1115

if(errno != ECHILD){