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1 | /* $OpenBSD: auth-options.c,v 1.43 2008/06/10 23:06:19 djm Exp $ */ | |
2 | /* | |
3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
6 | * As far as I am concerned, the code I have written for this software | |
7 | * can be used freely for any purpose. Any derived versions of this | |
8 | * software must be clearly marked as such, and if the derived work is | |
9 | * incompatible with the protocol description in the RFC file, it must be | |
10 | * called by a name other than "ssh" or "Secure Shell". | |
11 | */ | |
12 | ||
13 | #include "includes.h" | |
14 | ||
15 | #include <sys/types.h> | |
16 | ||
17 | #include <netdb.h> | |
18 | #include <pwd.h> | |
19 | #include <string.h> | |
20 | #include <stdio.h> | |
21 | #include <stdarg.h> | |
22 | ||
23 | #include "openbsd-compat/sys-queue.h" | |
24 | #include "xmalloc.h" | |
25 | #include "match.h" | |
26 | #include "log.h" | |
27 | #include "canohost.h" | |
28 | #include "buffer.h" | |
29 | #include "channels.h" | |
30 | #include "auth-options.h" | |
31 | #include "servconf.h" | |
32 | #include "misc.h" | |
33 | #include "key.h" | |
34 | #include "hostfile.h" | |
35 | #include "auth.h" | |
36 | #ifdef GSSAPI | |
37 | #include "ssh-gss.h" | |
38 | #endif | |
39 | #include "monitor_wrap.h" | |
40 | ||
41 | /* Flags set authorized_keys flags */ | |
42 | int no_port_forwarding_flag = 0; | |
43 | int no_agent_forwarding_flag = 0; | |
44 | int no_x11_forwarding_flag = 0; | |
45 | int no_pty_flag = 0; | |
46 | int no_user_rc = 0; | |
47 | ||
48 | /* "command=" option. */ | |
49 | char *forced_command = NULL; | |
50 | ||
51 | /* "environment=" options. */ | |
52 | struct envstring *custom_environment = NULL; | |
53 | ||
54 | /* "tunnel=" option. */ | |
55 | int forced_tun_device = -1; | |
56 | ||
57 | extern ServerOptions options; | |
58 | ||
59 | void | |
60 | auth_clear_options(void) | |
61 | { | |
62 | no_agent_forwarding_flag = 0; | |
63 | no_port_forwarding_flag = 0; | |
64 | no_pty_flag = 0; | |
65 | no_x11_forwarding_flag = 0; | |
66 | no_user_rc = 0; | |
67 | while (custom_environment) { | |
68 | struct envstring *ce = custom_environment; | |
69 | custom_environment = ce->next; | |
70 | xfree(ce->s); | |
71 | xfree(ce); | |
72 | } | |
73 | if (forced_command) { | |
74 | xfree(forced_command); | |
75 | forced_command = NULL; | |
76 | } | |
77 | forced_tun_device = -1; | |
78 | channel_clear_permitted_opens(); | |
79 | auth_debug_reset(); | |
80 | } | |
81 | ||
82 | /* | |
83 | * return 1 if access is granted, 0 if not. | |
84 | * side effect: sets key option flags | |
85 | */ | |
86 | int | |
87 | auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum) | |
88 | { | |
89 | const char *cp; | |
90 | int i; | |
91 | ||
92 | /* reset options */ | |
93 | auth_clear_options(); | |
94 | ||
95 | if (!opts) | |
96 | return 1; | |
97 | ||
98 | while (*opts && *opts != ' ' && *opts != '\t') { | |
99 | cp = "no-port-forwarding"; | |
100 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
101 | auth_debug_add("Port forwarding disabled."); | |
102 | no_port_forwarding_flag = 1; | |
103 | opts += strlen(cp); | |
104 | goto next_option; | |
105 | } | |
106 | cp = "no-agent-forwarding"; | |
107 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
108 | auth_debug_add("Agent forwarding disabled."); | |
109 | no_agent_forwarding_flag = 1; | |
110 | opts += strlen(cp); | |
111 | goto next_option; | |
112 | } | |
113 | cp = "no-X11-forwarding"; | |
114 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
115 | auth_debug_add("X11 forwarding disabled."); | |
116 | no_x11_forwarding_flag = 1; | |
117 | opts += strlen(cp); | |
118 | goto next_option; | |
119 | } | |
120 | cp = "no-pty"; | |
121 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
122 | auth_debug_add("Pty allocation disabled."); | |
123 | no_pty_flag = 1; | |
124 | opts += strlen(cp); | |
125 | goto next_option; | |
126 | } | |
127 | cp = "no-user-rc"; | |
128 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
129 | auth_debug_add("User rc file execution disabled."); | |
130 | no_user_rc = 1; | |
131 | opts += strlen(cp); | |
132 | goto next_option; | |
133 | } | |
134 | cp = "command=\""; | |
135 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
136 | opts += strlen(cp); | |
137 | forced_command = xmalloc(strlen(opts) + 1); | |
138 | i = 0; | |
139 | while (*opts) { | |
140 | if (*opts == '"') | |
141 | break; | |
142 | if (*opts == '\\' && opts[1] == '"') { | |
143 | opts += 2; | |
144 | forced_command[i++] = '"'; | |
145 | continue; | |
146 | } | |
147 | forced_command[i++] = *opts++; | |
148 | } | |
149 | if (!*opts) { | |
150 | debug("%.100s, line %lu: missing end quote", | |
151 | file, linenum); | |
152 | auth_debug_add("%.100s, line %lu: missing end quote", | |
153 | file, linenum); | |
154 | xfree(forced_command); | |
155 | forced_command = NULL; | |
156 | goto bad_option; | |
157 | } | |
158 | forced_command[i] = '\0'; | |
159 | auth_debug_add("Forced command: %.900s", forced_command); | |
160 | opts++; | |
161 | goto next_option; | |
162 | } | |
163 | cp = "environment=\""; | |
164 | if (options.permit_user_env && | |
165 | strncasecmp(opts, cp, strlen(cp)) == 0) { | |
166 | char *s; | |
167 | struct envstring *new_envstring; | |
168 | ||
169 | opts += strlen(cp); | |
170 | s = xmalloc(strlen(opts) + 1); | |
171 | i = 0; | |
172 | while (*opts) { | |
173 | if (*opts == '"') | |
174 | break; | |
175 | if (*opts == '\\' && opts[1] == '"') { | |
176 | opts += 2; | |
177 | s[i++] = '"'; | |
178 | continue; | |
179 | } | |
180 | s[i++] = *opts++; | |
181 | } | |
182 | if (!*opts) { | |
183 | debug("%.100s, line %lu: missing end quote", | |
184 | file, linenum); | |
185 | auth_debug_add("%.100s, line %lu: missing end quote", | |
186 | file, linenum); | |
187 | xfree(s); | |
188 | goto bad_option; | |
189 | } | |
190 | s[i] = '\0'; | |
191 | auth_debug_add("Adding to environment: %.900s", s); | |
192 | debug("Adding to environment: %.900s", s); | |
193 | opts++; | |
194 | new_envstring = xmalloc(sizeof(struct envstring)); | |
195 | new_envstring->s = s; | |
196 | new_envstring->next = custom_environment; | |
197 | custom_environment = new_envstring; | |
198 | goto next_option; | |
199 | } | |
200 | cp = "from=\""; | |
201 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
202 | const char *remote_ip = get_remote_ipaddr(); | |
203 | const char *remote_host = get_canonical_hostname( | |
204 | options.use_dns); | |
205 | char *patterns = xmalloc(strlen(opts) + 1); | |
206 | ||
207 | opts += strlen(cp); | |
208 | i = 0; | |
209 | while (*opts) { | |
210 | if (*opts == '"') | |
211 | break; | |
212 | if (*opts == '\\' && opts[1] == '"') { | |
213 | opts += 2; | |
214 | patterns[i++] = '"'; | |
215 | continue; | |
216 | } | |
217 | patterns[i++] = *opts++; | |
218 | } | |
219 | if (!*opts) { | |
220 | debug("%.100s, line %lu: missing end quote", | |
221 | file, linenum); | |
222 | auth_debug_add("%.100s, line %lu: missing end quote", | |
223 | file, linenum); | |
224 | xfree(patterns); | |
225 | goto bad_option; | |
226 | } | |
227 | patterns[i] = '\0'; | |
228 | opts++; | |
229 | switch (match_host_and_ip(remote_host, remote_ip, | |
230 | patterns)) { | |
231 | case 1: | |
232 | xfree(patterns); | |
233 | /* Host name matches. */ | |
234 | goto next_option; | |
235 | case -1: | |
236 | debug("%.100s, line %lu: invalid criteria", | |
237 | file, linenum); | |
238 | auth_debug_add("%.100s, line %lu: " | |
239 | "invalid criteria", file, linenum); | |
240 | /* FALLTHROUGH */ | |
241 | case 0: | |
242 | xfree(patterns); | |
243 | logit("Authentication tried for %.100s with " | |
244 | "correct key but not from a permitted " | |
245 | "host (host=%.200s, ip=%.200s).", | |
246 | pw->pw_name, remote_host, remote_ip); | |
247 | auth_debug_add("Your host '%.200s' is not " | |
248 | "permitted to use this key for login.", | |
249 | remote_host); | |
250 | break; | |
251 | } | |
252 | /* deny access */ | |
253 | return 0; | |
254 | } | |
255 | cp = "permitopen=\""; | |
256 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
257 | char *host, *p; | |
258 | u_short port; | |
259 | char *patterns = xmalloc(strlen(opts) + 1); | |
260 | ||
261 | opts += strlen(cp); | |
262 | i = 0; | |
263 | while (*opts) { | |
264 | if (*opts == '"') | |
265 | break; | |
266 | if (*opts == '\\' && opts[1] == '"') { | |
267 | opts += 2; | |
268 | patterns[i++] = '"'; | |
269 | continue; | |
270 | } | |
271 | patterns[i++] = *opts++; | |
272 | } | |
273 | if (!*opts) { | |
274 | debug("%.100s, line %lu: missing end quote", | |
275 | file, linenum); | |
276 | auth_debug_add("%.100s, line %lu: missing " | |
277 | "end quote", file, linenum); | |
278 | xfree(patterns); | |
279 | goto bad_option; | |
280 | } | |
281 | patterns[i] = '\0'; | |
282 | opts++; | |
283 | p = patterns; | |
284 | host = hpdelim(&p); | |
285 | if (host == NULL || strlen(host) >= NI_MAXHOST) { | |
286 | debug("%.100s, line %lu: Bad permitopen " | |
287 | "specification <%.100s>", file, linenum, | |
288 | patterns); | |
289 | auth_debug_add("%.100s, line %lu: " | |
290 | "Bad permitopen specification", file, | |
291 | linenum); | |
292 | xfree(patterns); | |
293 | goto bad_option; | |
294 | } | |
295 | host = cleanhostname(host); | |
296 | if (p == NULL || (port = a2port(p)) == 0) { | |
297 | debug("%.100s, line %lu: Bad permitopen port " | |
298 | "<%.100s>", file, linenum, p ? p : ""); | |
299 | auth_debug_add("%.100s, line %lu: " | |
300 | "Bad permitopen port", file, linenum); | |
301 | xfree(patterns); | |
302 | goto bad_option; | |
303 | } | |
304 | if (options.allow_tcp_forwarding) | |
305 | channel_add_permitted_opens(host, port); | |
306 | xfree(patterns); | |
307 | goto next_option; | |
308 | } | |
309 | cp = "tunnel=\""; | |
310 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
311 | char *tun = NULL; | |
312 | opts += strlen(cp); | |
313 | tun = xmalloc(strlen(opts) + 1); | |
314 | i = 0; | |
315 | while (*opts) { | |
316 | if (*opts == '"') | |
317 | break; | |
318 | tun[i++] = *opts++; | |
319 | } | |
320 | if (!*opts) { | |
321 | debug("%.100s, line %lu: missing end quote", | |
322 | file, linenum); | |
323 | auth_debug_add("%.100s, line %lu: missing end quote", | |
324 | file, linenum); | |
325 | xfree(tun); | |
326 | forced_tun_device = -1; | |
327 | goto bad_option; | |
328 | } | |
329 | tun[i] = '\0'; | |
330 | forced_tun_device = a2tun(tun, NULL); | |
331 | xfree(tun); | |
332 | if (forced_tun_device == SSH_TUNID_ERR) { | |
333 | debug("%.100s, line %lu: invalid tun device", | |
334 | file, linenum); | |
335 | auth_debug_add("%.100s, line %lu: invalid tun device", | |
336 | file, linenum); | |
337 | forced_tun_device = -1; | |
338 | goto bad_option; | |
339 | } | |
340 | auth_debug_add("Forced tun device: %d", forced_tun_device); | |
341 | opts++; | |
342 | goto next_option; | |
343 | } | |
344 | next_option: | |
345 | /* | |
346 | * Skip the comma, and move to the next option | |
347 | * (or break out if there are no more). | |
348 | */ | |
349 | if (!*opts) | |
350 | fatal("Bugs in auth-options.c option processing."); | |
351 | if (*opts == ' ' || *opts == '\t') | |
352 | break; /* End of options. */ | |
353 | if (*opts != ',') | |
354 | goto bad_option; | |
355 | opts++; | |
356 | /* Process the next option. */ | |
357 | } | |
358 | ||
359 | if (!use_privsep) | |
360 | auth_debug_send(); | |
361 | ||
362 | /* grant access */ | |
363 | return 1; | |
364 | ||
365 | bad_option: | |
366 | logit("Bad options in %.100s file, line %lu: %.50s", | |
367 | file, linenum, opts); | |
368 | auth_debug_add("Bad options in %.100s file, line %lu: %.50s", | |
369 | file, linenum, opts); | |
370 | ||
371 | if (!use_privsep) | |
372 | auth_debug_send(); | |
373 | ||
374 | /* deny access */ | |
375 | return 0; | |
376 | } |