1: /*
2: * Copyright (c) 2009-2011 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 <stdio.h>
23: #ifdef STDC_HEADERS
24: # include <stdlib.h>
25: # include <stddef.h>
26: #else
27: # ifdef HAVE_STDLIB_H
28: # include <stdlib.h>
29: # endif
30: #endif /* STDC_HEADERS */
31: #ifdef HAVE_STRING_H
32: # include <string.h>
33: #endif /* HAVE_STRING_H */
34: #ifdef HAVE_STRINGS_H
35: # include <strings.h>
36: #endif /* HAVE_STRINGS_H */
37: #ifdef HAVE_UNISTD_H
38: # include <unistd.h>
39: #endif /* HAVE_UNISTD_H */
40: #ifdef HAVE_DLOPEN
41: # include <dlfcn.h>
42: #else
43: # include "compat/dlfcn.h"
44: #endif
45: #include <errno.h>
46:
47: #include "sudo.h"
48: #include "sudo_plugin.h"
49: #include "sudo_plugin_int.h"
50:
51: #ifndef RTLD_GLOBAL
52: # define RTLD_GLOBAL 0
53: #endif
54:
55: #ifdef _PATH_SUDO_NOEXEC
56: const char *noexec_path = _PATH_SUDO_NOEXEC;
57: #endif
58:
59: /*
60: * Read in /etc/sudo.conf
61: * Returns a list of plugins.
62: */
63: static struct plugin_info_list *
64: sudo_read_conf(const char *conf_file)
65: {
66: FILE *fp;
67: char *cp, *name, *path;
68: struct plugin_info *info;
69: static struct plugin_info_list pil; /* XXX */
70:
71: if ((fp = fopen(conf_file, "r")) == NULL)
72: goto done;
73:
74: while ((cp = sudo_parseln(fp)) != NULL) {
75: /* Skip blank or comment lines */
76: if (*cp == '\0')
77: continue;
78:
79: /* Look for a line starting with "Path" */
80: if (strncasecmp(cp, "Path", 4) == 0) {
81: /* Parse line */
82: if ((name = strtok(cp + 4, " \t")) == NULL ||
83: (path = strtok(NULL, " \t")) == NULL) {
84: continue;
85: }
86: if (strcasecmp(name, "askpass") == 0)
87: askpass_path = estrdup(path);
88: #ifdef _PATH_SUDO_NOEXEC
89: else if (strcasecmp(name, "noexec") == 0)
90: noexec_path = estrdup(path);
91: #endif
92: continue;
93: }
94:
95: /* Look for a line starting with "Plugin" */
96: if (strncasecmp(cp, "Plugin", 6) == 0) {
97: /* Parse line */
98: if ((name = strtok(cp + 6, " \t")) == NULL ||
99: (path = strtok(NULL, " \t")) == NULL) {
100: continue;
101: }
102: info = emalloc(sizeof(*info));
103: info->symbol_name = estrdup(name);
104: info->path = estrdup(path);
105: info->prev = info;
106: info->next = NULL;
107: tq_append(&pil, info);
108: continue;
109: }
110: }
111: fclose(fp);
112:
113: done:
114: if (tq_empty(&pil)) {
115: /* Default policy plugin */
116: info = emalloc(sizeof(*info));
117: info->symbol_name = "sudoers_policy";
118: info->path = SUDOERS_PLUGIN;
119: info->prev = info;
120: info->next = NULL;
121: tq_append(&pil, info);
122:
123: /* Default I/O plugin */
124: info = emalloc(sizeof(*info));
125: info->symbol_name = "sudoers_io";
126: info->path = SUDOERS_PLUGIN;
127: info->prev = info;
128: info->next = NULL;
129: tq_append(&pil, info);
130: }
131:
132: return &pil;
133: }
134:
135: /*
136: * Load the plugins listed in conf_file.
137: */
138: int
139: sudo_load_plugins(const char *conf_file,
140: struct plugin_container *policy_plugin,
141: struct plugin_container_list *io_plugins)
142: {
143: struct generic_plugin *plugin;
144: struct plugin_container *container;
145: struct plugin_info *info;
146: struct plugin_info_list *plugin_list;
147: struct stat sb;
148: void *handle;
149: char path[PATH_MAX];
150: int rval = FALSE;
151:
152: /* Parse sudo.conf */
153: plugin_list = sudo_read_conf(conf_file);
154:
155: tq_foreach_fwd(plugin_list, info) {
156: if (info->path[0] == '/') {
157: if (strlcpy(path, info->path, sizeof(path)) >= sizeof(path)) {
158: warningx(_("%s: %s"), info->path, strerror(ENAMETOOLONG));
159: goto done;
160: }
161: } else {
162: if (snprintf(path, sizeof(path), "%s%s", _PATH_SUDO_PLUGIN_DIR,
163: info->path) >= sizeof(path)) {
164: warningx(_("%s%s: %s"), _PATH_SUDO_PLUGIN_DIR, info->path,
165: strerror(ENAMETOOLONG));
166: goto done;
167: }
168: }
169: if (stat(path, &sb) != 0) {
170: warning("%s", path);
171: goto done;
172: }
173: if (sb.st_uid != ROOT_UID) {
174: warningx(_("%s must be owned by uid %d"), path, ROOT_UID);
175: goto done;
176: }
177: if ((sb.st_mode & (S_IWGRP|S_IWOTH)) != 0) {
178: warningx(_("%s must be only be writable by owner"), path);
179: goto done;
180: }
181:
182: /* Open plugin and map in symbol */
183: handle = dlopen(path, RTLD_LAZY|RTLD_GLOBAL);
184: if (!handle) {
185: warningx(_("unable to dlopen %s: %s"), path, dlerror());
186: goto done;
187: }
188: plugin = dlsym(handle, info->symbol_name);
189: if (!plugin) {
190: warningx(_("%s: unable to find symbol %s"), path,
191: info->symbol_name);
192: goto done;
193: }
194:
195: if (plugin->type != SUDO_POLICY_PLUGIN && plugin->type != SUDO_IO_PLUGIN) {
196: warningx(_("%s: unknown policy type %d"), path, plugin->type);
197: goto done;
198: }
199: if (SUDO_API_VERSION_GET_MAJOR(plugin->version) != SUDO_API_VERSION_MAJOR) {
200: warningx(_("%s: incompatible policy major version %d, expected %d"),
201: path, SUDO_API_VERSION_GET_MAJOR(plugin->version),
202: SUDO_API_VERSION_MAJOR);
203: goto done;
204: }
205: if (plugin->type == SUDO_POLICY_PLUGIN) {
206: if (policy_plugin->handle) {
207: warningx(_("%s: only a single policy plugin may be loaded"),
208: conf_file);
209: goto done;
210: }
211: policy_plugin->handle = handle;
212: policy_plugin->name = info->symbol_name;
213: policy_plugin->u.generic = plugin;
214: } else if (plugin->type == SUDO_IO_PLUGIN) {
215: container = emalloc(sizeof(*container));
216: container->prev = container;
217: container->next = NULL;
218: container->handle = handle;
219: container->name = info->symbol_name;
220: container->u.generic = plugin;
221: tq_append(io_plugins, container);
222: }
223: }
224: if (policy_plugin->handle == NULL) {
225: warningx(_("%s: at least one policy plugin must be specified"),
226: conf_file);
227: goto done;
228: }
229: if (policy_plugin->u.policy->check_policy == NULL) {
230: warningx(_("policy plugin %s does not include a check_policy method"),
231: policy_plugin->name);
232: goto done;
233: }
234:
235: rval = TRUE;
236:
237: done:
238: return rval;
239: }
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