Annotation of embedaddon/sudo/plugins/sample/sample_plugin.c, revision 1.1.1.3
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 */
1.1.1.2 misho 33: #ifdef HAVE_STDBOOL_H
34: # include <stdbool.h>
35: #else
36: # include "compat/stdbool.h"
37: #endif /* HAVE_STDBOOL_H */
1.1 misho 38: #ifdef HAVE_STRING_H
39: # if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
40: # include <memory.h>
41: # endif
42: # include <string.h>
43: #endif /* HAVE_STRING_H */
44: #ifdef HAVE_STRINGS_H
45: # include <strings.h>
46: #endif /* HAVE_STRINGS_H */
47: #ifdef HAVE_UNISTD_H
48: # include <unistd.h>
49: #endif /* HAVE_UNISTD_H */
50: #include <ctype.h>
51: #include <fcntl.h>
52: #include <limits.h>
53: #include <grp.h>
54: #include <pwd.h>
55: #include <stdarg.h>
56:
57: #include <pathnames.h>
58: #include "sudo_plugin.h"
59: #include "missing.h"
60:
61: /*
62: * Sample plugin module that allows any user who knows the password
63: * ("test") to run any command as root. Since there is no credential
64: * caching the validate and invalidate functions are NULL.
65: */
66:
67: #ifdef __TANDEM
68: # define ROOT_UID 65535
69: #else
70: # define ROOT_UID 0
71: #endif
72:
73: static struct plugin_state {
74: char **envp;
75: char * const *settings;
76: char * const *user_info;
77: } plugin_state;
78: static sudo_conv_t sudo_conv;
79: static sudo_printf_t sudo_log;
80: static FILE *input, *output;
81: static uid_t runas_uid = ROOT_UID;
82: static gid_t runas_gid = -1;
1.1.1.2 misho 83: static int use_sudoedit = false;
1.1 misho 84:
85: /*
86: * Allocate storage for a name=value string and return it.
87: */
88: static char *
89: fmt_string(const char *var, const char *val)
90: {
91: size_t var_len = strlen(var);
92: size_t val_len = strlen(val);
93: char *cp, *str;
94:
95: cp = str = malloc(var_len + 1 + val_len + 1);
96: if (str != NULL) {
97: memcpy(cp, var, var_len);
98: cp += var_len;
99: *cp++ = '=';
100: memcpy(cp, val, val_len);
101: cp += val_len;
102: *cp = '\0';
103: }
104:
105: return str;
106: }
107:
108: /*
109: * Plugin policy open function.
110: */
111: static int
112: policy_open(unsigned int version, sudo_conv_t conversation,
113: sudo_printf_t sudo_printf, char * const settings[],
1.1.1.2 misho 114: char * const user_info[], char * const user_env[], char * const args[])
1.1 misho 115: {
116: char * const *ui;
117: struct passwd *pw;
118: const char *runas_user = NULL;
119: struct group *gr;
120: const char *runas_group = NULL;
121:
122: if (!sudo_conv)
123: sudo_conv = conversation;
124: if (!sudo_log)
125: sudo_log = sudo_printf;
126:
127: if (SUDO_API_VERSION_GET_MAJOR(version) != SUDO_API_VERSION_MAJOR) {
128: sudo_log(SUDO_CONV_ERROR_MSG,
129: "the sample plugin requires API version %d.x\n",
130: SUDO_API_VERSION_MAJOR);
1.1.1.2 misho 131: return -1;
1.1 misho 132: }
133:
134: /* Only allow commands to be run as root. */
135: for (ui = settings; *ui != NULL; ui++) {
136: if (strncmp(*ui, "runas_user=", sizeof("runas_user=") - 1) == 0) {
137: runas_user = *ui + sizeof("runas_user=") - 1;
138: }
139: if (strncmp(*ui, "runas_group=", sizeof("runas_group=") - 1) == 0) {
140: runas_group = *ui + sizeof("runas_group=") - 1;
141: }
142: #if !defined(HAVE_GETPROGNAME) && !defined(HAVE___PROGNAME)
143: if (strncmp(*ui, "progname=", sizeof("progname=") - 1) == 0) {
144: setprogname(*ui + sizeof("progname=") - 1);
145: }
146: #endif
147: /* Check to see if sudo was called as sudoedit or with -e flag. */
148: if (strncmp(*ui, "sudoedit=", sizeof("sudoedit=") - 1) == 0) {
149: if (strcasecmp(*ui + sizeof("sudoedit=") - 1, "true") == 0)
1.1.1.2 misho 150: use_sudoedit = true;
1.1 misho 151: }
152: /* This plugin doesn't support running sudo with no arguments. */
153: if (strncmp(*ui, "implied_shell=", sizeof("implied_shell=") - 1) == 0) {
154: if (strcasecmp(*ui + sizeof("implied_shell=") - 1, "true") == 0)
155: return -2; /* usage error */
156: }
157: }
158: if (runas_user != NULL) {
159: if ((pw = getpwnam(runas_user)) == NULL) {
160: sudo_log(SUDO_CONV_ERROR_MSG, "unknown user %s\n", runas_user);
161: return 0;
162: }
163: runas_uid = pw->pw_uid;
164: }
165: if (runas_group != NULL) {
166: if ((gr = getgrnam(runas_group)) == NULL) {
167: sudo_log(SUDO_CONV_ERROR_MSG, "unknown group %s\n", runas_group);
168: return 0;
169: }
170: runas_gid = gr->gr_gid;
171: }
172:
173: /* Plugin state. */
174: plugin_state.envp = (char **)user_env;
175: plugin_state.settings = settings;
176: plugin_state.user_info = user_info;
177:
178: return 1;
179: }
180:
181: static char *
182: find_in_path(char *command, char **envp)
183: {
184: struct stat sb;
185: char *path, *path0, **ep, *cp;
186: char pathbuf[PATH_MAX], *qualified = NULL;
187:
188: if (strchr(command, '/') != NULL)
189: return command;
190:
191: path = _PATH_DEFPATH;
192: for (ep = plugin_state.envp; *ep != NULL; ep++) {
193: if (strncmp(*ep, "PATH=", 5) == 0) {
194: path = *ep + 5;
195: break;
196: }
197: }
198: path = path0 = strdup(path);
199: do {
200: if ((cp = strchr(path, ':')))
201: *cp = '\0';
202: snprintf(pathbuf, sizeof(pathbuf), "%s/%s", *path ? path : ".",
203: command);
204: if (stat(pathbuf, &sb) == 0) {
205: if (S_ISREG(sb.st_mode) && (sb.st_mode & 0000111)) {
206: qualified = pathbuf;
207: break;
208: }
209: }
210: path = cp + 1;
211: } while (cp != NULL);
212: free(path0);
213: return qualified ? strdup(qualified) : NULL;
214: }
215:
216: static int
217: check_passwd(void)
218: {
219: struct sudo_conv_message msg;
220: struct sudo_conv_reply repl;
221:
222: /* Prompt user for password via conversation function. */
223: memset(&msg, 0, sizeof(msg));
224: msg.msg_type = SUDO_CONV_PROMPT_ECHO_OFF;
225: msg.msg = "Password: ";
226: memset(&repl, 0, sizeof(repl));
227: sudo_conv(1, &msg, &repl);
228: if (repl.reply == NULL) {
229: sudo_log(SUDO_CONV_ERROR_MSG, "missing password\n");
1.1.1.2 misho 230: return false;
1.1 misho 231: }
232: if (strcmp(repl.reply, "test") != 0) {
233: sudo_log(SUDO_CONV_ERROR_MSG, "incorrect password\n");
1.1.1.2 misho 234: return false;
1.1 misho 235: }
1.1.1.2 misho 236: return true;
1.1 misho 237: }
238:
239: static char **
1.1.1.3 ! misho 240: build_command_info(const char *command)
1.1 misho 241: {
242: static char **command_info;
243: int i = 0;
244:
245: /* Setup command info. */
246: command_info = calloc(32, sizeof(char *));
247: if (command_info == NULL)
248: return NULL;
249: if ((command_info[i++] = fmt_string("command", command)) == NULL ||
250: asprintf(&command_info[i++], "runas_euid=%ld", (long)runas_uid) == -1 ||
251: asprintf(&command_info[i++], "runas_uid=%ld", (long)runas_uid) == -1) {
252: return NULL;
253: }
254: if (runas_gid != -1) {
255: if (asprintf(&command_info[i++], "runas_gid=%ld", (long)runas_gid) == -1 ||
256: asprintf(&command_info[i++], "runas_egid=%ld", (long)runas_gid) == -1) {
257: return NULL;
258: }
259: }
260: if (use_sudoedit) {
261: command_info[i] = strdup("sudoedit=true");
262: if (command_info[i++] == NULL)
263: return NULL;
264: }
265: #ifdef USE_TIMEOUT
266: command_info[i++] = "timeout=30";
267: #endif
268: return command_info;
269: }
270:
271: static char *
272: find_editor(int nfiles, char * const files[], char **argv_out[])
273: {
274: char *cp, **ep, **nargv, *editor, *editor_path;
275: int ac, i, nargc, wasblank;
276:
277: /* Lookup EDITOR in user's environment. */
278: editor = _PATH_VI;
279: for (ep = plugin_state.envp; *ep != NULL; ep++) {
280: if (strncmp(*ep, "EDITOR=", 7) == 0) {
281: editor = *ep + 7;
282: break;
283: }
284: }
285: editor = strdup(editor);
286: if (editor == NULL) {
287: sudo_log(SUDO_CONV_ERROR_MSG, "unable to allocate memory\n");
288: return NULL;
289: }
290:
291: /*
292: * Split editor into an argument vector; editor is reused (do not free).
293: * The EDITOR environment variables may contain command
294: * line args so look for those and alloc space for them too.
295: */
296: nargc = 1;
297: for (wasblank = 0, cp = editor; *cp != '\0'; cp++) {
298: if (isblank((unsigned char) *cp))
299: wasblank = 1;
300: else if (wasblank) {
301: wasblank = 0;
302: nargc++;
303: }
304: }
305: /* If we can't find the editor in the user's PATH, give up. */
306: cp = strtok(editor, " \t");
307: if (cp == NULL ||
308: (editor_path = find_in_path(editor, plugin_state.envp)) == NULL) {
309: return NULL;
310: }
1.1.1.3 ! misho 311: if (editor_path != editor)
! 312: free(editor);
1.1 misho 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");
1.1.1.3 ! misho 316: free(editor_path);
1.1 misho 317: return NULL;
318: }
319: for (ac = 0; cp != NULL && ac < nargc; ac++) {
320: nargv[ac] = cp;
321: cp = strtok(NULL, " \t");
322: }
323: nargv[ac++] = "--";
324: for (i = 0; i < nfiles; )
325: nargv[ac++] = files[i++];
326: nargv[ac] = NULL;
327:
328: *argv_out = nargv;
329: return editor_path;
330: }
331:
332: /*
333: * Plugin policy check function.
334: * Simple example that prompts for a password, hard-coded to "test".
335: */
336: static int
337: policy_check(int argc, char * const argv[],
338: char *env_add[], char **command_info_out[],
339: char **argv_out[], char **user_env_out[])
340: {
341: char *command;
342:
343: if (!argc || argv[0] == NULL) {
344: sudo_log(SUDO_CONV_ERROR_MSG, "no command specified\n");
1.1.1.2 misho 345: return false;
1.1 misho 346: }
347:
348: if (!check_passwd())
1.1.1.2 misho 349: return false;
1.1 misho 350:
351: command = find_in_path(argv[0], plugin_state.envp);
352: if (command == NULL) {
353: sudo_log(SUDO_CONV_ERROR_MSG, "%s: command not found\n", argv[0]);
1.1.1.2 misho 354: return false;
1.1 misho 355: }
356:
357: /* If "sudo vi" is run, auto-convert to sudoedit. */
358: if (strcmp(command, _PATH_VI) == 0)
1.1.1.2 misho 359: use_sudoedit = true;
1.1 misho 360:
361: if (use_sudoedit) {
362: /* Rebuild argv using editor */
1.1.1.3 ! misho 363: free(command);
1.1 misho 364: command = find_editor(argc - 1, argv + 1, argv_out);
365: if (command == NULL) {
366: sudo_log(SUDO_CONV_ERROR_MSG, "unable to find valid editor\n");
1.1.1.2 misho 367: return -1;
1.1 misho 368: }
1.1.1.2 misho 369: use_sudoedit = true;
1.1 misho 370: } else {
371: /* No changes needd to argv */
372: *argv_out = (char **)argv;
373: }
374:
375: /* No changes to envp */
376: *user_env_out = plugin_state.envp;
377:
378: /* Setup command info. */
379: *command_info_out = build_command_info(command);
1.1.1.3 ! misho 380: free(command);
1.1 misho 381: if (*command_info_out == NULL) {
382: sudo_log(SUDO_CONV_ERROR_MSG, "out of memory\n");
1.1.1.2 misho 383: return -1;
1.1 misho 384: }
385:
1.1.1.2 misho 386: return true;
1.1 misho 387: }
388:
389: static int
390: policy_list(int argc, char * const argv[], int verbose, const char *list_user)
391: {
392: /*
393: * List user's capabilities.
394: */
395: sudo_log(SUDO_CONV_INFO_MSG, "Validated users may run any command\n");
1.1.1.2 misho 396: return true;
1.1 misho 397: }
398:
399: static int
400: policy_version(int verbose)
401: {
402: sudo_log(SUDO_CONV_INFO_MSG, "Sample policy plugin version %s\n", PACKAGE_VERSION);
1.1.1.2 misho 403: return true;
1.1 misho 404: }
405:
406: static void
407: policy_close(int exit_status, int error)
408: {
409: /*
410: * The policy might log the command exit status here.
411: * In this example, we just print a message.
412: */
413: if (error) {
414: sudo_log(SUDO_CONV_ERROR_MSG, "Command error: %s\n", strerror(error));
415: } else {
416: if (WIFEXITED(exit_status)) {
417: sudo_log(SUDO_CONV_INFO_MSG, "Command exited with status %d\n",
418: WEXITSTATUS(exit_status));
419: } else if (WIFSIGNALED(exit_status)) {
420: sudo_log(SUDO_CONV_INFO_MSG, "Command killed by signal %d\n",
421: WTERMSIG(exit_status));
422: }
423: }
424: }
425:
426: static int
427: io_open(unsigned int version, sudo_conv_t conversation,
428: sudo_printf_t sudo_printf, char * const settings[],
429: char * const user_info[], char * const command_info[],
1.1.1.2 misho 430: int argc, char * const argv[], char * const user_env[], char * const args[])
1.1 misho 431: {
432: int fd;
433: char path[PATH_MAX];
434:
435: if (!sudo_conv)
436: sudo_conv = conversation;
437: if (!sudo_log)
438: sudo_log = sudo_printf;
439:
440: /* Open input and output files. */
441: snprintf(path, sizeof(path), "/var/tmp/sample-%u.output",
442: (unsigned int)getpid());
443: fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0644);
444: if (fd == -1)
1.1.1.2 misho 445: return false;
1.1 misho 446: output = fdopen(fd, "w");
447:
448: snprintf(path, sizeof(path), "/var/tmp/sample-%u.input",
449: (unsigned int)getpid());
450: fd = open(path, O_WRONLY|O_CREAT|O_EXCL, 0644);
451: if (fd == -1)
1.1.1.2 misho 452: return false;
1.1 misho 453: input = fdopen(fd, "w");
454:
1.1.1.2 misho 455: return true;
1.1 misho 456: }
457:
458: static void
459: io_close(int exit_status, int error)
460: {
461: fclose(input);
462: fclose(output);
463: }
464:
465: static int
466: io_version(int verbose)
467: {
468: sudo_log(SUDO_CONV_INFO_MSG, "Sample I/O plugin version %s\n",
469: PACKAGE_VERSION);
1.1.1.2 misho 470: return true;
1.1 misho 471: }
472:
473: static int
474: io_log_input(const char *buf, unsigned int len)
475: {
1.1.1.2 misho 476: ignore_result(fwrite(buf, len, 1, input));
477: return true;
1.1 misho 478: }
479:
480: static int
481: io_log_output(const char *buf, unsigned int len)
482: {
1.1.1.2 misho 483: ignore_result(fwrite(buf, len, 1, output));
484: return true;
1.1 misho 485: }
486:
487: struct policy_plugin sample_policy = {
488: SUDO_POLICY_PLUGIN,
489: SUDO_API_VERSION,
490: policy_open,
491: policy_close,
492: policy_version,
493: policy_check,
494: policy_list,
495: NULL, /* validate */
1.1.1.2 misho 496: NULL, /* invalidate */
497: NULL, /* init_session */
498: NULL, /* register_hooks */
499: NULL /* deregister_hooks */
1.1 misho 500: };
501:
502: /*
503: * Note: This plugin does not differentiate between tty and pipe I/O.
504: * It all gets logged to the same file.
505: */
506: struct io_plugin sample_io = {
507: SUDO_IO_PLUGIN,
508: SUDO_API_VERSION,
509: io_open,
510: io_close,
511: io_version,
512: io_log_input, /* tty input */
513: io_log_output, /* tty output */
514: io_log_input, /* command stdin if not tty */
515: io_log_output, /* command stdout if not tty */
516: io_log_output /* command stderr if not tty */
517: };
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