1: /*
2: * Copyright (c) 2010-2013 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/stat.h>
21: #include <sys/wait.h>
22:
23: #include <stdio.h>
24: #ifdef STDC_HEADERS
25: # include <stdlib.h>
26: # include <stddef.h>
27: #else
28: # ifdef HAVE_STDLIB_H
29: # include <stdlib.h>
30: # endif
31: #endif /* STDC_HEADERS */
32: #ifdef HAVE_STDBOOL_H
33: # include <stdbool.h>
34: #else
35: # include "compat/stdbool.h"
36: #endif /* HAVE_STDBOOL_H */
37: #ifdef HAVE_STRING_H
38: # if defined(HAVE_MEMORY_H) && !defined(STDC_HEADERS)
39: # include <memory.h>
40: # endif
41: # include <string.h>
42: #endif /* HAVE_STRING_H */
43: #ifdef HAVE_STRINGS_H
44: # include <strings.h>
45: #endif /* HAVE_STRINGS_H */
46: #ifdef HAVE_UNISTD_H
47: # include <unistd.h>
48: #endif /* HAVE_UNISTD_H */
49: #include <ctype.h>
50: #include <fcntl.h>
51: #include <limits.h>
52: #include <grp.h>
53: #include <pwd.h>
54: #include <stdarg.h>
55:
56: #include <pathnames.h>
57: #include "sudo_plugin.h"
58: #include "missing.h"
59:
60: /*
61: * Sample plugin module that allows any user who knows the password
62: * ("test") to run any command as root. Since there is no credential
63: * caching the validate and invalidate functions are NULL.
64: */
65:
66: #ifdef __TANDEM
67: # define ROOT_UID 65535
68: #else
69: # define ROOT_UID 0
70: #endif
71:
72: static struct plugin_state {
73: char **envp;
74: char * const *settings;
75: char * const *user_info;
76: } plugin_state;
77: static sudo_conv_t sudo_conv;
78: static sudo_printf_t sudo_log;
79: static FILE *input, *output;
80: static uid_t runas_uid = ROOT_UID;
81: static gid_t runas_gid = -1;
82: static int use_sudoedit = false;
83:
84: /*
85: * Allocate storage for a name=value string and return it.
86: */
87: static char *
88: fmt_string(const char *var, const char *val)
89: {
90: size_t var_len = strlen(var);
91: size_t val_len = strlen(val);
92: char *cp, *str;
93:
94: cp = str = malloc(var_len + 1 + val_len + 1);
95: if (str != NULL) {
96: memcpy(cp, var, var_len);
97: cp += var_len;
98: *cp++ = '=';
99: memcpy(cp, val, val_len);
100: cp += val_len;
101: *cp = '\0';
102: }
103:
104: return str;
105: }
106:
107: /*
108: * Plugin policy open function.
109: */
110: static int
111: policy_open(unsigned int version, sudo_conv_t conversation,
112: sudo_printf_t sudo_printf, char * const settings[],
113: char * const user_info[], char * const user_env[], char * const args[])
114: {
115: char * const *ui;
116: struct passwd *pw;
117: const char *runas_user = NULL;
118: struct group *gr;
119: const char *runas_group = NULL;
120:
121: if (!sudo_conv)
122: sudo_conv = conversation;
123: if (!sudo_log)
124: sudo_log = sudo_printf;
125:
126: if (SUDO_API_VERSION_GET_MAJOR(version) != SUDO_API_VERSION_MAJOR) {
127: sudo_log(SUDO_CONV_ERROR_MSG,
128: "the sample plugin requires API version %d.x\n",
129: SUDO_API_VERSION_MAJOR);
130: return -1;
131: }
132:
133: /* Only allow commands to be run as root. */
134: for (ui = settings; *ui != NULL; ui++) {
135: if (strncmp(*ui, "runas_user=", sizeof("runas_user=") - 1) == 0) {
136: runas_user = *ui + sizeof("runas_user=") - 1;
137: }
138: if (strncmp(*ui, "runas_group=", sizeof("runas_group=") - 1) == 0) {
139: runas_group = *ui + sizeof("runas_group=") - 1;
140: }
141: #if !defined(HAVE_GETPROGNAME) && !defined(HAVE___PROGNAME)
142: if (strncmp(*ui, "progname=", sizeof("progname=") - 1) == 0) {
143: setprogname(*ui + sizeof("progname=") - 1);
144: }
145: #endif
146: /* Check to see if sudo was called as sudoedit or with -e flag. */
147: if (strncmp(*ui, "sudoedit=", sizeof("sudoedit=") - 1) == 0) {
148: if (strcasecmp(*ui + sizeof("sudoedit=") - 1, "true") == 0)
149: use_sudoedit = true;
150: }
151: /* This plugin doesn't support running sudo with no arguments. */
152: if (strncmp(*ui, "implied_shell=", sizeof("implied_shell=") - 1) == 0) {
153: if (strcasecmp(*ui + sizeof("implied_shell=") - 1, "true") == 0)
154: return -2; /* usage error */
155: }
156: }
157: if (runas_user != NULL) {
158: if ((pw = getpwnam(runas_user)) == NULL) {
159: sudo_log(SUDO_CONV_ERROR_MSG, "unknown user %s\n", runas_user);
160: return 0;
161: }
162: runas_uid = pw->pw_uid;
163: }
164: if (runas_group != NULL) {
165: if ((gr = getgrnam(runas_group)) == NULL) {
166: sudo_log(SUDO_CONV_ERROR_MSG, "unknown group %s\n", runas_group);
167: return 0;
168: }
169: runas_gid = gr->gr_gid;
170: }
171:
172: /* Plugin state. */
173: plugin_state.envp = (char **)user_env;
174: plugin_state.settings = settings;
175: plugin_state.user_info = user_info;
176:
177: return 1;
178: }
179:
180: static char *
181: find_in_path(char *command, char **envp)
182: {
183: struct stat sb;
184: char *path, *path0, **ep, *cp;
185: char pathbuf[PATH_MAX], *qualified = NULL;
186:
187: if (strchr(command, '/') != NULL)
188: return command;
189:
190: path = _PATH_DEFPATH;
191: for (ep = plugin_state.envp; *ep != NULL; ep++) {
192: if (strncmp(*ep, "PATH=", 5) == 0) {
193: path = *ep + 5;
194: break;
195: }
196: }
197: path = path0 = strdup(path);
198: do {
199: if ((cp = strchr(path, ':')))
200: *cp = '\0';
201: snprintf(pathbuf, sizeof(pathbuf), "%s/%s", *path ? path : ".",
202: command);
203: if (stat(pathbuf, &sb) == 0) {
204: if (S_ISREG(sb.st_mode) && (sb.st_mode & 0000111)) {
205: qualified = pathbuf;
206: break;
207: }
208: }
209: path = cp + 1;
210: } while (cp != NULL);
211: free(path0);
212: return qualified ? strdup(qualified) : NULL;
213: }
214:
215: static int
216: check_passwd(void)
217: {
218: struct sudo_conv_message msg;
219: struct sudo_conv_reply repl;
220:
221: /* Prompt user for password via conversation function. */
222: memset(&msg, 0, sizeof(msg));
223: msg.msg_type = SUDO_CONV_PROMPT_ECHO_OFF;
224: msg.msg = "Password: ";
225: memset(&repl, 0, sizeof(repl));
226: sudo_conv(1, &msg, &repl);
227: if (repl.reply == NULL) {
228: sudo_log(SUDO_CONV_ERROR_MSG, "missing password\n");
229: return false;
230: }
231: if (strcmp(repl.reply, "test") != 0) {
232: sudo_log(SUDO_CONV_ERROR_MSG, "incorrect password\n");
233: return false;
234: }
235: return true;
236: }
237:
238: static char **
239: build_command_info(const char *command)
240: {
241: static char **command_info;
242: int i = 0;
243:
244: /* Setup command info. */
245: command_info = calloc(32, sizeof(char *));
246: if (command_info == NULL)
247: return NULL;
248: if ((command_info[i++] = fmt_string("command", command)) == NULL ||
249: asprintf(&command_info[i++], "runas_euid=%ld", (long)runas_uid) == -1 ||
250: asprintf(&command_info[i++], "runas_uid=%ld", (long)runas_uid) == -1) {
251: return NULL;
252: }
253: if (runas_gid != -1) {
254: if (asprintf(&command_info[i++], "runas_gid=%ld", (long)runas_gid) == -1 ||
255: asprintf(&command_info[i++], "runas_egid=%ld", (long)runas_gid) == -1) {
256: return NULL;
257: }
258: }
259: if (use_sudoedit) {
260: command_info[i] = strdup("sudoedit=true");
261: if (command_info[i++] == NULL)
262: return NULL;
263: }
264: #ifdef USE_TIMEOUT
265: command_info[i++] = "timeout=30";
266: #endif
267: return command_info;
268: }
269:
270: static char *
271: find_editor(int nfiles, char * const files[], char **argv_out[])
272: {
273: char *cp, **ep, **nargv, *editor, *editor_path;
274: int ac, i, nargc, wasblank;
275:
276: /* Lookup EDITOR in user's environment. */
277: editor = _PATH_VI;
278: for (ep = plugin_state.envp; *ep != NULL; ep++) {
279: if (strncmp(*ep, "EDITOR=", 7) == 0) {
280: editor = *ep + 7;
281: break;
282: }
283: }
284: editor = strdup(editor);
285: if (editor == NULL) {
286: sudo_log(SUDO_CONV_ERROR_MSG, "unable to allocate memory\n");
287: return NULL;
288: }
289:
290: /*
291: * Split editor into an argument vector; editor is reused (do not free).
292: * The EDITOR environment variables may contain command
293: * line args so look for those and alloc space for them too.
294: */
295: nargc = 1;
296: for (wasblank = 0, cp = editor; *cp != '\0'; cp++) {
297: if (isblank((unsigned char) *cp))
298: wasblank = 1;
299: else if (wasblank) {
300: wasblank = 0;
301: nargc++;
302: }
303: }
304: /* If we can't find the editor in the user's PATH, give up. */
305: cp = strtok(editor, " \t");
306: if (cp == NULL ||
307: (editor_path = find_in_path(editor, plugin_state.envp)) == NULL) {
308: free(editor);
309: return NULL;
310: }
311: if (editor_path != editor)
312: free(editor);
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: free(editor_path);
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");
345: return false;
346: }
347:
348: if (!check_passwd())
349: return false;
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]);
354: return false;
355: }
356:
357: /* If "sudo vi" is run, auto-convert to sudoedit. */
358: if (strcmp(command, _PATH_VI) == 0)
359: use_sudoedit = true;
360:
361: if (use_sudoedit) {
362: /* Rebuild argv using editor */
363: free(command);
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");
367: return -1;
368: }
369: use_sudoedit = true;
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);
380: free(command);
381: if (*command_info_out == NULL) {
382: sudo_log(SUDO_CONV_ERROR_MSG, "out of memory\n");
383: return -1;
384: }
385:
386: return true;
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");
396: return true;
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);
403: return true;
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[],
430: int argc, char * const argv[], char * const user_env[], char * const args[])
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)
445: return false;
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)
452: return false;
453: input = fdopen(fd, "w");
454:
455: return true;
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);
470: return true;
471: }
472:
473: static int
474: io_log_input(const char *buf, unsigned int len)
475: {
476: ignore_result(fwrite(buf, len, 1, input));
477: return true;
478: }
479:
480: static int
481: io_log_output(const char *buf, unsigned int len)
482: {
483: ignore_result(fwrite(buf, len, 1, output));
484: return true;
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 */
496: NULL, /* invalidate */
497: NULL, /* init_session */
498: NULL, /* register_hooks */
499: NULL /* deregister_hooks */
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: __dso_public 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: };
FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>
![[BACK]](/icons/cvsweb/back.gif){kind=icon}
Return to sample_plugin.c CVS log ![[TXT]](/icons/cvsweb/text.gif){kind=icon}
![[DIR]](/icons/cvsweb/dir.gif){kind=icon}
Up to [ELWIX - Embedded LightWeight unIX -] / embedaddon / sudo / plugins / sample