/mandos/trunk : revision 384

1

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

1

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

2

/*

3

* Mandos plugin runner - Run Mandos plugins

4

*

23

*/

24

25

#define _GNU_SOURCE /* TEMP_FAILURE_RETRY(), getline(),

26

asprintf() */

26

asprintf(), O_CLOEXEC */

27

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

28

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

29

EXIT_SUCCESS, realloc() */

30

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

31

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

32

stderr, STDOUT_FILENO */

33

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

33

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

34

stat, waitpid(), WIFEXITED(),

35

WEXITSTATUS(), wait(), pid_t,

36

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

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

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

45

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

45

46

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

46

47

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

47

48

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

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,

65

67

SIG_UNBLOCK, kill(), sig_atomic_t

66

68

*/

67

69

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

68

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

70

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

69

71

70

72

#define BUFFER_SIZE 256

71

73

82

84

char **environ;

83

85

int envc;

84

86

bool disabled;

85

87

86

88

/* Variables used for running processes*/

87

89

pid_t pid;

88

90

int fd;

108

110

}

109

111

}

110

112

/* Create a new plugin */

111

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);

112

117

if(new_plugin == NULL){

113

118

return NULL;

114

119

}

115

120

char *copy_name = NULL;

116

121

if(name != NULL){

117

copy_name = strdup(name);

122

do {

123

copy_name = strdup(name);

124

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

118

125

if(copy_name == NULL){

119

126

free(new_plugin);

120

127

return NULL;

126

133

.disabled = false,

127

134

.next = plugin_list };

128

135

129

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);

130

139

if(new_plugin->argv == NULL){

131

140

free(copy_name);

132

141

free(new_plugin);

135

144

new_plugin->argv[0] = copy_name;

136

145

new_plugin->argv[1] = NULL;

137

146

138

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

147

do {

148

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

149

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

139

150

if(new_plugin->environ == NULL){

140

151

free(copy_name);

141

152

free(new_plugin->argv);

153

164

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

154

165

int *len){

155

166

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

156

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

157

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

167

do {

168

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

169

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

170

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

158

171

/* Malloc check */

159

172

if(*array == NULL){

160

173

return false;

161

174

}

162

175

/* Make a copy of the new string */

163

char *copy = strdup(new);

176

char *copy;

177

do {

178

copy = strdup(new);

179

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

164

180

if(copy == NULL){

165

181

return false;

166

182

}

192

208

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

193

209

/* It already exists */

194

210

if(replace){

195

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);

196

215

if(new == NULL){

197

216

return false;

198

217

}

208

227

/*

209

228

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

210

229

* Descriptor Flags".

211

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

230

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

212

231

*/

213

232

static int set_cloexec_flag(int fd){

214

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

233

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

215

234

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

216

235

if(ret < 0){

217

236

return ret;

218

237

}

219

238

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

220

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

239

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

240

ret | FD_CLOEXEC));

221

241

}

222

242

223

243

280

300

}

281

301

free(plugin_node->environ);

282

302

free(plugin_node->buffer);

283

303

284

304

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

285

305

if(plugin_node == plugin_list){

286

306

/* First one - simple */

313

333

struct dirent *dirst;

314

334

struct stat st;

315

335

fd_set rfds_all;

316

int ret, numchars, maxfd = 0;

336

int ret, maxfd = 0;

317

337

ssize_t sret;

318

intmax_t tmpmax;

319

338

uid_t uid = 65534;

320

339

gid_t gid = 65534;

321

340

bool debug = false;

381

400

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

382

401

struct argp_state *state){

383

402

switch(key){

403

char *tmp;

404

intmax_t tmpmax;

384

405

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

385

406

if(arg != NULL){

386

407

char *plugin_option;

456

477

plugindir = strdup(arg);

457

478

if(plugindir == NULL){

458

479

perror("strdup");

459

}

480

}

460

481

break;

461

482

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

462

483

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

463

484

break;

464

485

case 130: /* --userid */

465

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

466

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

467

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){

468

490

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

469

491

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

470

492

} else {

472

494

}

473

495

break;

474

496

case 131: /* --groupid */

475

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

476

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

477

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){

478

501

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

479

502

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

480

503

} else {

524

547

if(argfile == NULL){

525

548

perror("strdup");

526

549

}

527

break;

550

break;

528

551

case 130: /* --userid */

529

552

case 131: /* --groupid */

530

553

case 132: /* --debug */

559

582

conffp = fopen(AFILE, "r");

560

583

} else {

561

584

conffp = fopen(argfile, "r");

562

}

585

}

563

586

if(conffp != NULL){

564

587

char *org_line = NULL;

565

588

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

566

589

size_t size = 0;

567

590

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

568

591

const char comment_delim[] = "#";

569

592

570

593

custom_argc = 1;

571

594

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

572

595

if(custom_argv == NULL){

576

599

}

577

600

custom_argv[0] = argv[0];

578

601

custom_argv[1] = NULL;

579

602

580

603

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

581

604

commented text */

582

605

while(true){

584

607

if(sret == -1){

585

608

break;

586

609

}

587

610

588

611

line = org_line;

589

612

arg = strsep(&line, comment_delim);

590

613

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

609

632

goto fallback;

610

633

}

611

634

custom_argv[custom_argc-1] = new_arg;

612

custom_argv[custom_argc] = NULL;

635

custom_argv[custom_argc] = NULL;

613

636

}

614

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

}

615

646

free(org_line);

616

647

} else {

617

648

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

667

698

perror("setuid");

668

699

}

669

700

670

if(plugindir == NULL){

671

dir = opendir(PDIR);

672

} else {

673

dir = opendir(plugindir);

674

}

675

676

if(dir == NULL){

677

perror("Could not open plugin dir");

678

exitstatus = EXIT_FAILURE;

679

goto fallback;

680

}

681

682

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

701

/* Open plugin directory with close_on_exec flag */

683

702

{

684

int dir_fd = dirfd(dir);

685

if(dir_fd >= 0){

686

ret = set_cloexec_flag(dir_fd);

687

if(ret < 0){

688

perror("set_cloexec_flag");

689

exitstatus = EXIT_FAILURE;

690

goto fallback;

691

}

703

int dir_fd = -1;

704

if(plugindir == NULL){

705

dir_fd = open(PDIR, O_RDONLY |

706

#ifdef O_CLOEXEC

707

O_CLOEXEC

708

#else /* not O_CLOEXEC */

709

0

710

#endif /* not O_CLOEXEC */

711

);

712

} else {

713

dir_fd = open(plugindir, O_RDONLY |

714

#ifdef O_CLOEXEC

715

O_CLOEXEC

716

#else /* not O_CLOEXEC */

717

0

718

#endif /* not O_CLOEXEC */

719

);

720

}

721

if(dir_fd == -1){

722

perror("Could not open plugin dir");

723

exitstatus = EXIT_FAILURE;

724

goto fallback;

725

}

726

727

#ifndef O_CLOEXEC

728

/* Set the FD_CLOEXEC flag on the directory */

729

ret = set_cloexec_flag(dir_fd);

730

if(ret < 0){

731

perror("set_cloexec_flag");

732

TEMP_FAILURE_RETRY(close(dir_fd));

733

exitstatus = EXIT_FAILURE;

734

goto fallback;

735

}

736

#endif /* O_CLOEXEC */

737

738

dir = fdopendir(dir_fd);

739

if(dir == NULL){

740

perror("Could not open plugin dir");

741

TEMP_FAILURE_RETRY(close(dir_fd));

742

exitstatus = EXIT_FAILURE;

743

goto fallback;

692

744

}

693

745

}

694

746

696

748

697

749

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

698

750

while(true){

699

dirst = readdir(dir);

751

do {

752

dirst = readdir(dir);

753

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

700

754

701

755

/* All directory entries have been processed */

702

756

if(dirst == NULL){

753

807

continue;

754

808

}

755

809

}

756

810

757

811

char *filename;

758

812

if(plugindir == NULL){

759

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

813

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

814

dirst->d_name));

760

815

} else {

761

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

816

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

817

plugindir,

818

dirst->d_name));

762

819

}

763

820

if(ret < 0){

764

821

perror("asprintf");

765

822

continue;

766

823

}

767

824

768

ret = stat(filename, &st);

825

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

769

826

if(ret == -1){

770

827

perror("stat");

771

828

free(filename);

772

829

continue;

773

830

}

774

831

775

832

/* Ignore non-executable files */

776

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

833

if(not S_ISREG(st.st_mode)

834

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

777

835

if(debug){

778

836

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

779

837

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

825

883

}

826

884

827

885

int pipefd[2];

828

ret = pipe(pipefd);

886

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

829

887

if(ret == -1){

830

888

perror("pipe");

831

889

exitstatus = EXIT_FAILURE;

845

903

goto fallback;

846

904

}

847

905

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

848

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

906

ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_BLOCK,

907

&sigchld_action.sa_mask,

908

NULL));

849

909

if(ret < 0){

850

910

perror("sigprocmask");

851

911

exitstatus = EXIT_FAILURE;

852

912

goto fallback;

853

913

}

854

914

/* Starting a new process to be watched */

855

pid_t pid = fork();

915

pid_t pid;

916

do {

917

pid = fork();

918

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

856

919

if(pid == -1){

857

920

perror("fork");

858

921

exitstatus = EXIT_FAILURE;

896

959

/* no return */

897

960

}

898

961

/* Parent process */

899

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

962

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

963

pipe */

900

964

free(filename);

901

965

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

902

966

if(new_plugin == NULL){

903

967

perror("getplugin");

904

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

968

ret = (int)(TEMP_FAILURE_RETRY

969

(sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,

970

NULL)));

905

971

if(ret < 0){

906

972

perror("sigprocmask");

907

973

}

914

980

915

981

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

916

982

has already completed */

917

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

983

ret = (int)TEMP_FAILURE_RETRY(sigprocmask(SIG_UNBLOCK,

984

&sigchld_action.sa_mask,

985

NULL));

918

986

if(ret < 0){

919

987

perror("sigprocmask");

920

988

exitstatus = EXIT_FAILURE;

921

989

goto fallback;

922

990

}

923

991

924

FD_SET(new_plugin->fd, &rfds_all);

992

FD_SET(new_plugin->fd, &rfds_all); /* Spurious warning from

993

-Wconversion */

925

994

926

995

if(maxfd < new_plugin->fd){

927

996

maxfd = new_plugin->fd;

928

997

}

929

998

}

930

999

931

closedir(dir);

1000

TEMP_FAILURE_RETRY(closedir(dir));

932

1001

dir = NULL;

933

1002

free_plugin(getplugin(NULL));

934

1003

947

1016

while(plugin_list){

948

1017

fd_set rfds = rfds_all;

949

1018

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

950

if(select_ret == -1){

1019

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

951

1020

perror("select");

952

1021

exitstatus = EXIT_FAILURE;

953

1022

goto fallback;

961

1030

if(not WIFEXITED(proc->status)

962

1031

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

963

1032

/* Bad exit by plugin */

964

1033

965

1034

if(debug){

966

1035

if(WIFEXITED(proc->status)){

967

1036

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

970

1039

WEXITSTATUS(proc->status));

971

1040

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

972

1041

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

973

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

1042

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

974

1043

(intmax_t) (proc->pid),

975

WTERMSIG(proc->status));

1044

WTERMSIG(proc->status),

1045

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

976

1046

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

977

1047

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

978

1048

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

980

1050

}

981

1051

982

1052

/* Remove the plugin */

983

FD_CLR(proc->fd, &rfds_all);

984

1053

FD_CLR(proc->fd, &rfds_all); /* Spurious warning from

1054

-Wconversion */

1055

985

1056

/* Block signal while modifying process_list */

986

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

1057

ret = (int)TEMP_FAILURE_RETRY(sigprocmask

1058

(SIG_BLOCK,

1059

&sigchld_action.sa_mask,

1060

NULL));

987

1061

if(ret < 0){

988

1062

perror("sigprocmask");

989

1063

exitstatus = EXIT_FAILURE;

995

1069

proc = next_plugin;

996

1070

997

1071

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

998

ret = sigprocmask(SIG_UNBLOCK, &sigchld_action.sa_mask,

999

NULL);

1072

ret = (int)(TEMP_FAILURE_RETRY

1073

(sigprocmask(SIG_UNBLOCK,

1074

&sigchld_action.sa_mask, NULL)));

1000

1075

if(ret < 0){

1001

1076

perror("sigprocmask");

1002

1077

exitstatus = EXIT_FAILURE;

1022

1097

}

1023

1098

1024

1099

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

1025

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

1100

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

1101

warning from

1102

-Wconversion */

1026

1103

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

1027

1104

proc = proc->next;

1028

1105

continue;

1039

1116

proc->buffer_size += BUFFER_SIZE;

1040

1117

}

1041

1118

/* Read from the process */

1042

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

1043

BUFFER_SIZE);

1119

sret = TEMP_FAILURE_RETRY(read(proc->fd,

1120

proc->buffer

1121

+ proc->buffer_length,

1122

BUFFER_SIZE));

1044

1123

if(sret < 0){

1045

1124

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

1046

1125

proc = proc->next;

1054

1133

}

1055

1134

}

1056

1135

}

1057

1058

1136

1137

1059

1138

fallback:

1060

1139

1061

1140

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

1108

1187

}

1109

1188

1110

1189

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

1111

do{

1190

do {

1112

1191

ret = wait(NULL);

1113

1192

} while(ret >= 0);

1114

1193

if(errno != ECHILD){