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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