Annotation of embedaddon/sudo/plugins/sample/sample_plugin.c, revision 1.1
1.1 ! misho 1: /*
! 2: * Copyright (c) 2010-2011 Todd C. Miller <Todd.Miller@courtesan.com>
! 3: *
! 4: * Permission to use, copy, modify, and distribute this software for any
! 5: * purpose with or without fee is hereby granted, provided that the above
! 6: * copyright notice and this permission notice appear in all copies.
! 7: *
! 8: * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
! 9: * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
! 10: * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
! 11: * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
! 12: * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
! 13: * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
! 14: * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
! 15: */
! 16:
! 17: #include <config.h>
! 18:
! 19: #include <sys/types.h>
! 20: #include <sys/param.h>
! 21: #include <sys/stat.h>
! 22: #include <sys/wait.h>
! 23:
! 24: #include <stdio.h>
! 25: #ifdef STDC_HEADERS
! 26: # include <stdlib.h>
! 27: # include <stddef.h>
! 28: #else
! 29: # ifdef HAVE_STDLIB_H
! 30: # include <stdlib.h>
! 31: # endif
! 32: #endif /* STDC_HEADERS */
! 33: #ifdef HAVE_STRING_H
! 34: # if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
! 35: # include <memory.h>
! 36: # endif
! 37: # include <string.h>
! 38: #endif /* HAVE_STRING_H */
! 39: #ifdef HAVE_STRINGS_H
! 40: # include <strings.h>
! 41: #endif /* HAVE_STRINGS_H */
! 42: #ifdef HAVE_UNISTD_H
! 43: # include <unistd.h>
! 44: #endif /* HAVE_UNISTD_H */
! 45: #include <ctype.h>
! 46: #include <fcntl.h>
! 47: #include <limits.h>
! 48: #include <grp.h>
! 49: #include <pwd.h>
! 50: #include <stdarg.h>
! 51:
! 52: #include <pathnames.h>
! 53: #include "sudo_plugin.h"
! 54: #include "missing.h"
! 55:
! 56: /*
! 57: * Sample plugin module that allows any user who knows the password
! 58: * ("test") to run any command as root. Since there is no credential
! 59: * caching the validate and invalidate functions are NULL.
! 60: */
! 61:
! 62: #ifdef __TANDEM
! 63: # define ROOT_UID 65535
! 64: #else
! 65: # define ROOT_UID 0
! 66: #endif
! 67:
! 68: #undef TRUE
! 69: #define TRUE 1
! 70: #undef FALSE
! 71: #define FALSE 0
! 72: #undef ERROR
! 73: #define ERROR -1
! 74:
! 75: static struct plugin_state {
! 76: char **envp;
! 77: char * const *settings;
! 78: char * const *user_info;
! 79: } plugin_state;
! 80: static sudo_conv_t sudo_conv;
! 81: static sudo_printf_t sudo_log;
! 82: static FILE *input, *output;
! 83: static uid_t runas_uid = ROOT_UID;
! 84: static gid_t runas_gid = -1;
! 85: static int use_sudoedit = FALSE;
! 86:
! 87: /*
! 88: * Allocate storage for a name=value string and return it.
! 89: */
! 90: static char *
! 91: fmt_string(const char *var, const char *val)
! 92: {
! 93: size_t var_len = strlen(var);
! 94: size_t val_len = strlen(val);
! 95: char *cp, *str;
! 96:
! 97: cp = str = malloc(var_len + 1 + val_len + 1);
! 98: if (str != NULL) {
! 99: memcpy(cp, var, var_len);
! 100: cp += var_len;
! 101: *cp++ = '=';
! 102: memcpy(cp, val, val_len);
! 103: cp += val_len;
! 104: *cp = '\0';
! 105: }
! 106:
! 107: return str;
! 108: }
! 109:
! 110: /*
! 111: * Plugin policy open function.
! 112: */
! 113: static int
! 114: policy_open(unsigned int version, sudo_conv_t conversation,
! 115: sudo_printf_t sudo_printf, char * const settings[],
! 116: char * const user_info[], char * const user_env[])
! 117: {
! 118: char * const *ui;
! 119: struct passwd *pw;
! 120: const char *runas_user = NULL;
! 121: struct group *gr;
! 122: const char *runas_group = NULL;
! 123:
! 124: if (!sudo_conv)
! 125: sudo_conv = conversation;
! 126: if (!sudo_log)
! 127: sudo_log = sudo_printf;
! 128:
! 129: if (SUDO_API_VERSION_GET_MAJOR(version) != SUDO_API_VERSION_MAJOR) {
! 130: sudo_log(SUDO_CONV_ERROR_MSG,
! 131: "the sample plugin requires API version %d.x\n",
! 132: SUDO_API_VERSION_MAJOR);
! 133: return ERROR;
! 134: }
! 135:
! 136: /* Only allow commands to be run as root. */
! 137: for (ui = settings; *ui != NULL; ui++) {
! 138: if (strncmp(*ui, "runas_user=", sizeof("runas_user=") - 1) == 0) {
! 139: runas_user = *ui + sizeof("runas_user=") - 1;
! 140: }
! 141: if (strncmp(*ui, "runas_group=", sizeof("runas_group=") - 1) == 0) {
! 142: runas_group = *ui + sizeof("runas_group=") - 1;
! 143: }
! 144: #if !defined(HAVE_GETPROGNAME) && !defined(HAVE___PROGNAME)
! 145: if (strncmp(*ui, "progname=", sizeof("progname=") - 1) == 0) {
! 146: setprogname(*ui + sizeof("progname=") - 1);
! 147: }
! 148: #endif
! 149: /* Check to see if sudo was called as sudoedit or with -e flag. */
! 150: if (strncmp(*ui, "sudoedit=", sizeof("sudoedit=") - 1) == 0) {
! 151: if (strcasecmp(*ui + sizeof("sudoedit=") - 1, "true") == 0)
! 152: use_sudoedit = TRUE;
! 153: }
! 154: /* This plugin doesn't support running sudo with no arguments. */
! 155: if (strncmp(*ui, "implied_shell=", sizeof("implied_shell=") - 1) == 0) {
! 156: if (strcasecmp(*ui + sizeof("implied_shell=") - 1, "true") == 0)
! 157: return -2; /* usage error */
! 158: }
! 159: }
! 160: if (runas_user != NULL) {
! 161: if ((pw = getpwnam(runas_user)) == NULL) {
! 162: sudo_log(SUDO_CONV_ERROR_MSG, "unknown user %s\n", runas_user);
! 163: return 0;
! 164: }
! 165: runas_uid = pw->pw_uid;
! 166: }
! 167: if (runas_group != NULL) {
! 168: if ((gr = getgrnam(runas_group)) == NULL) {
! 169: sudo_log(SUDO_CONV_ERROR_MSG, "unknown group %s\n", runas_group);
! 170: return 0;
! 171: }
! 172: runas_gid = gr->gr_gid;
! 173: }
! 174:
! 175: /* Plugin state. */
! 176: plugin_state.envp = (char **)user_env;
! 177: plugin_state.settings = settings;
! 178: plugin_state.user_info = user_info;
! 179:
! 180: return 1;
! 181: }
! 182:
! 183: static char *
! 184: find_in_path(char *command, char **envp)
! 185: {
! 186: struct stat sb;
! 187: char *path, *path0, **ep, *cp;
! 188: char pathbuf[PATH_MAX], *qualified = NULL;
! 189:
! 190: if (strchr(command, '/') != NULL)
! 191: return command;
! 192:
! 193: path = _PATH_DEFPATH;
! 194: for (ep = plugin_state.envp; *ep != NULL; ep++) {
! 195: if (strncmp(*ep, "PATH=", 5) == 0) {
! 196: path = *ep + 5;
! 197: break;
! 198: }
! 199: }
! 200: path = path0 = strdup(path);
! 201: do {
! 202: if ((cp = strchr(path, ':')))
! 203: *cp = '\0';
! 204: snprintf(pathbuf, sizeof(pathbuf), "%s/%s", *path ? path : ".",
! 205: command);
! 206: if (stat(pathbuf, &sb) == 0) {
! 207: if (S_ISREG(sb.st_mode) && (sb.st_mode & 0000111)) {
! 208: qualified = pathbuf;
! 209: break;
! 210: }
! 211: }
! 212: path = cp + 1;
! 213: } while (cp != NULL);
! 214: free(path0);
! 215: return qualified ? strdup(qualified) : NULL;
! 216: }
! 217:
! 218: static int
! 219: check_passwd(void)
! 220: {
! 221: struct sudo_conv_message msg;
! 222: struct sudo_conv_reply repl;
! 223:
! 224: /* Prompt user for password via conversation function. */
! 225: memset(&msg, 0, sizeof(msg));
! 226: msg.msg_type = SUDO_CONV_PROMPT_ECHO_OFF;
! 227: msg.msg = "Password: ";
! 228: memset(&repl, 0, sizeof(repl));
! 229: sudo_conv(1, &msg, &repl);
! 230: if (repl.reply == NULL) {
! 231: sudo_log(SUDO_CONV_ERROR_MSG, "missing password\n");
! 232: return FALSE;
! 233: }
! 234: if (strcmp(repl.reply, "test") != 0) {
! 235: sudo_log(SUDO_CONV_ERROR_MSG, "incorrect password\n");
! 236: return FALSE;
! 237: }
! 238: return TRUE;
! 239: }
! 240:
! 241: static char **
! 242: build_command_info(char *command)
! 243: {
! 244: static char **command_info;
! 245: int i = 0;
! 246:
! 247: /* Setup command info. */
! 248: command_info = calloc(32, sizeof(char *));
! 249: if (command_info == NULL)
! 250: return NULL;
! 251: if ((command_info[i++] = fmt_string("command", command)) == NULL ||
! 252: asprintf(&command_info[i++], "runas_euid=%ld", (long)runas_uid) == -1 ||
! 253: asprintf(&command_info[i++], "runas_uid=%ld", (long)runas_uid) == -1) {
! 254: return NULL;
! 255: }
! 256: if (runas_gid != -1) {
! 257: if (asprintf(&command_info[i++], "runas_gid=%ld", (long)runas_gid) == -1 ||
! 258: asprintf(&command_info[i++], "runas_egid=%ld", (long)runas_gid) == -1) {
! 259: return NULL;
! 260: }
! 261: }
! 262: if (use_sudoedit) {
! 263: command_info[i] = strdup("sudoedit=true");
! 264: if (command_info[i++] == NULL)
! 265: return NULL;
! 266: }
! 267: #ifdef USE_TIMEOUT
! 268: command_info[i++] = "timeout=30";
! 269: #endif
! 270: return command_info;
! 271: }
! 272:
! 273: static char *
! 274: find_editor(int nfiles, char * const files[], char **argv_out[])
! 275: {
! 276: char *cp, **ep, **nargv, *editor, *editor_path;
! 277: int ac, i, nargc, wasblank;
! 278:
! 279: /* Lookup EDITOR in user's environment. */
! 280: editor = _PATH_VI;
! 281: for (ep = plugin_state.envp; *ep != NULL; ep++) {
! 282: if (strncmp(*ep, "EDITOR=", 7) == 0) {
! 283: editor = *ep + 7;
! 284: break;
! 285: }
! 286: }
! 287: editor = strdup(editor);
! 288: if (editor == NULL) {
! 289: sudo_log(SUDO_CONV_ERROR_MSG, "unable to allocate memory\n");
! 290: return NULL;
! 291: }
! 292:
! 293: /*
! 294: * Split editor into an argument vector; editor is reused (do not free).
! 295: * The EDITOR environment variables may contain command
! 296: * line args so look for those and alloc space for them too.
! 297: */
! 298: nargc = 1;
! 299: for (wasblank = 0, cp = editor; *cp != '\0'; cp++) {
! 300: if (isblank((unsigned char) *cp))
! 301: wasblank = 1;
! 302: else if (wasblank) {
! 303: wasblank = 0;
! 304: nargc++;
! 305: }
! 306: }
! 307: /* If we can't find the editor in the user's PATH, give up. */
! 308: cp = strtok(editor, " \t");
! 309: if (cp == NULL ||
! 310: (editor_path = find_in_path(editor, plugin_state.envp)) == NULL) {
! 311: return NULL;
! 312: }
! 313: nargv = (char **) malloc((nargc + 1 + nfiles + 1) * sizeof(char *));
! 314: if (nargv == NULL) {
! 315: sudo_log(SUDO_CONV_ERROR_MSG, "unable to allocate memory\n");
! 316: return NULL;
! 317: }
! 318: for (ac = 0; cp != NULL && ac < nargc; ac++) {
! 319: nargv[ac] = cp;
! 320: cp = strtok(NULL, " \t");
! 321: }
! 322: nargv[ac++] = "--";
! 323: for (i = 0; i < nfiles; )
! 324: nargv[ac++] = files[i++];
! 325: nargv[ac] = NULL;
! 326:
! 327: *argv_out = nargv;
! 328: return editor_path;
! 329: }
! 330:
! 331: /*
! 332: * Plugin policy check function.
! 333: * Simple example that prompts for a password, hard-coded to "test".
! 334: */
! 335: static int
! 336: policy_check(int argc, char * const argv[],
! 337: char *env_add[], char **command_info_out[],
! 338: char **argv_out[], char **user_env_out[])
! 339: {
! 340: char *command;
! 341:
! 342: if (!argc || argv[0] == NULL) {
! 343: sudo_log(SUDO_CONV_ERROR_MSG, "no command specified\n");
! 344: return FALSE;
! 345: }
! 346:
! 347: if (!check_passwd())
! 348: return FALSE;
! 349:
! 350: command = find_in_path(argv[0], plugin_state.envp);
! 351: if (command == NULL) {
! 352: sudo_log(SUDO_CONV_ERROR_MSG, "%s: command not found\n", argv[0]);
! 353: return FALSE;
! 354: }
! 355:
! 356: /* If "sudo vi" is run, auto-convert to sudoedit. */
! 357: if (strcmp(command, _PATH_VI) == 0)
! 358: use_sudoedit = TRUE;
! 359:
! 360: if (use_sudoedit) {
! 361: /* Rebuild argv using editor */
! 362: command = find_editor(argc - 1, argv + 1, argv_out);
! 363: if (command == NULL) {
! 364: sudo_log(SUDO_CONV_ERROR_MSG, "unable to find valid editor\n");
! 365: return ERROR;
! 366: }
! 367: use_sudoedit = TRUE;
! 368: } else {
! 369: /* No changes needd to argv */
! 370: *argv_out = (char **)argv;
! 371: }
! 372:
! 373: /* No changes to envp */
! 374: *user_env_out = plugin_state.envp;
! 375:
! 376: /* Setup command info. */
! 377: *command_info_out = build_command_info(command);
! 378: if (*command_info_out == NULL) {
! 379: sudo_log(SUDO_CONV_ERROR_MSG, "out of memory\n");
! 380: return ERROR;
! 381: }
! 382:
! 383: return TRUE;
! 384: }
! 385:
! 386: static int
! 387: policy_list(int argc, char * const argv[], int verbose, const char *list_user)
! 388: {
! 389: /*
! 390: * List user's capabilities.
! 391: */
! 392: sudo_log(SUDO_CONV_INFO_MSG, "Validated users may run any command\n");
! 393: return TRUE;
! 394: }
! 395:
! 396: static int
! 397: policy_version(int verbose)
! 398: {
! 399: sudo_log(SUDO_CONV_INFO_MSG, "Sample policy plugin version %s\n", PACKAGE_VERSION);
! 400: return TRUE;
! 401: }
! 402:
! 403: static void
! 404: policy_close(int exit_status, int error)
! 405: {
! 406: /*
! 407: * The policy might log the command exit status here.
! 408: * In this example, we just print a message.
! 409: */
! 410: if (error) {
! 411: sudo_log(SUDO_CONV_ERROR_MSG, "Command error: %s\n", strerror(error));
! 412: } else {
! 413: if (WIFEXITED(exit_status)) {
! 414: sudo_log(SUDO_CONV_INFO_MSG, "Command exited with status %d\n",
! 415: WEXITSTATUS(exit_status));
! 416: } else if (WIFSIGNALED(exit_status)) {
! 417: sudo_log(SUDO_CONV_INFO_MSG, "Command killed by signal %d\n",
! 418: WTERMSIG(exit_status));
! 419: }
! 420: }
! 421: }
! 422:
! 423: static int
! 424: io_open(unsigned int version, sudo_conv_t conversation,
! 425: sudo_printf_t sudo_printf, char * const settings[],
! 426: char * const user_info[], char * const command_info[],
! 427: int argc, char * const argv[], char * const user_env[])
! 428: {
! 429: int fd;
! 430: char path[PATH_MAX];
! 431:
! 432: if (!sudo_conv)
! 433: sudo_conv = conversation;
! 434: if (!sudo_log)
! 435: sudo_log = sudo_printf;
! 436:
! 437: /* Open input and output files. */
! 438: snprintf(path, sizeof(path), "/var/tmp/sample-%u.output",
! 439: (unsigned int)getpid());
! 440: fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0644);
! 441: if (fd == -1)
! 442: return FALSE;
! 443: output = fdopen(fd, "w");
! 444:
! 445: snprintf(path, sizeof(path), "/var/tmp/sample-%u.input",
! 446: (unsigned int)getpid());
! 447: fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0644);
! 448: if (fd == -1)
! 449: return FALSE;
! 450: input = fdopen(fd, "w");
! 451:
! 452: return TRUE;
! 453: }
! 454:
! 455: static void
! 456: io_close(int exit_status, int error)
! 457: {
! 458: fclose(input);
! 459: fclose(output);
! 460: }
! 461:
! 462: static int
! 463: io_version(int verbose)
! 464: {
! 465: sudo_log(SUDO_CONV_INFO_MSG, "Sample I/O plugin version %s\n",
! 466: PACKAGE_VERSION);
! 467: return TRUE;
! 468: }
! 469:
! 470: static int
! 471: io_log_input(const char *buf, unsigned int len)
! 472: {
! 473: fwrite(buf, len, 1, input);
! 474: return TRUE;
! 475: }
! 476:
! 477: static int
! 478: io_log_output(const char *buf, unsigned int len)
! 479: {
! 480: fwrite(buf, len, 1, output);
! 481: return TRUE;
! 482: }
! 483:
! 484: struct policy_plugin sample_policy = {
! 485: SUDO_POLICY_PLUGIN,
! 486: SUDO_API_VERSION,
! 487: policy_open,
! 488: policy_close,
! 489: policy_version,
! 490: policy_check,
! 491: policy_list,
! 492: NULL, /* validate */
! 493: NULL /* invalidate */
! 494: };
! 495:
! 496: /*
! 497: * Note: This plugin does not differentiate between tty and pipe I/O.
! 498: * It all gets logged to the same file.
! 499: */
! 500: struct io_plugin sample_io = {
! 501: SUDO_IO_PLUGIN,
! 502: SUDO_API_VERSION,
! 503: io_open,
! 504: io_close,
! 505: io_version,
! 506: io_log_input, /* tty input */
! 507: io_log_output, /* tty output */
! 508: io_log_input, /* command stdin if not tty */
! 509: io_log_output, /* command stdout if not tty */
! 510: io_log_output /* command stderr if not tty */
! 511: };
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