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1 | /* | |
2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * As far as I am concerned, the code I have written for this software | |
6 | * can be used freely for any purpose. Any derived versions of this | |
7 | * software must be clearly marked as such, and if the derived work is | |
8 | * incompatible with the protocol description in the RFC file, it must be | |
9 | * called by a name other than "ssh" or "Secure Shell". | |
10 | */ | |
11 | ||
12 | #include "includes.h" | |
13 | RCSID("$OpenBSD: auth-options.c,v 1.15 2001/03/16 19:06:28 markus Exp $"); | |
14 | ||
15 | #include "packet.h" | |
16 | #include "xmalloc.h" | |
17 | #include "match.h" | |
18 | #include "log.h" | |
19 | #include "canohost.h" | |
20 | #include "channels.h" | |
21 | #include "auth-options.h" | |
22 | #include "servconf.h" | |
23 | ||
24 | /* Flags set authorized_keys flags */ | |
25 | int no_port_forwarding_flag = 0; | |
26 | int no_agent_forwarding_flag = 0; | |
27 | int no_x11_forwarding_flag = 0; | |
28 | int no_pty_flag = 0; | |
29 | ||
30 | /* "command=" option. */ | |
31 | char *forced_command = NULL; | |
32 | ||
33 | /* "environment=" options. */ | |
34 | struct envstring *custom_environment = NULL; | |
35 | ||
36 | extern ServerOptions options; | |
37 | ||
38 | void | |
39 | auth_clear_options(void) | |
40 | { | |
41 | no_agent_forwarding_flag = 0; | |
42 | no_port_forwarding_flag = 0; | |
43 | no_pty_flag = 0; | |
44 | no_x11_forwarding_flag = 0; | |
45 | while (custom_environment) { | |
46 | struct envstring *ce = custom_environment; | |
47 | custom_environment = ce->next; | |
48 | xfree(ce->s); | |
49 | xfree(ce); | |
50 | } | |
51 | if (forced_command) { | |
52 | xfree(forced_command); | |
53 | forced_command = NULL; | |
54 | } | |
55 | channel_clear_permitted_opens(); | |
56 | } | |
57 | ||
58 | /* | |
59 | * return 1 if access is granted, 0 if not. | |
60 | * side effect: sets key option flags | |
61 | */ | |
62 | int | |
63 | auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum) | |
64 | { | |
65 | const char *cp; | |
66 | int i; | |
67 | ||
68 | /* reset options */ | |
69 | auth_clear_options(); | |
70 | ||
71 | if (!opts) | |
72 | return 1; | |
73 | ||
74 | while (*opts && *opts != ' ' && *opts != '\t') { | |
75 | cp = "no-port-forwarding"; | |
76 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
77 | packet_send_debug("Port forwarding disabled."); | |
78 | no_port_forwarding_flag = 1; | |
79 | opts += strlen(cp); | |
80 | goto next_option; | |
81 | } | |
82 | cp = "no-agent-forwarding"; | |
83 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
84 | packet_send_debug("Agent forwarding disabled."); | |
85 | no_agent_forwarding_flag = 1; | |
86 | opts += strlen(cp); | |
87 | goto next_option; | |
88 | } | |
89 | cp = "no-X11-forwarding"; | |
90 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
91 | packet_send_debug("X11 forwarding disabled."); | |
92 | no_x11_forwarding_flag = 1; | |
93 | opts += strlen(cp); | |
94 | goto next_option; | |
95 | } | |
96 | cp = "no-pty"; | |
97 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
98 | packet_send_debug("Pty allocation disabled."); | |
99 | no_pty_flag = 1; | |
100 | opts += strlen(cp); | |
101 | goto next_option; | |
102 | } | |
103 | cp = "command=\""; | |
104 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
105 | opts += strlen(cp); | |
106 | forced_command = xmalloc(strlen(opts) + 1); | |
107 | i = 0; | |
108 | while (*opts) { | |
109 | if (*opts == '"') | |
110 | break; | |
111 | if (*opts == '\\' && opts[1] == '"') { | |
112 | opts += 2; | |
113 | forced_command[i++] = '"'; | |
114 | continue; | |
115 | } | |
116 | forced_command[i++] = *opts++; | |
117 | } | |
118 | if (!*opts) { | |
119 | debug("%.100s, line %lu: missing end quote", | |
120 | file, linenum); | |
121 | packet_send_debug("%.100s, line %lu: missing end quote", | |
122 | file, linenum); | |
123 | xfree(forced_command); | |
124 | forced_command = NULL; | |
125 | goto bad_option; | |
126 | } | |
127 | forced_command[i] = 0; | |
128 | packet_send_debug("Forced command: %.900s", forced_command); | |
129 | opts++; | |
130 | goto next_option; | |
131 | } | |
132 | cp = "environment=\""; | |
133 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
134 | char *s; | |
135 | struct envstring *new_envstring; | |
136 | ||
137 | opts += strlen(cp); | |
138 | s = xmalloc(strlen(opts) + 1); | |
139 | i = 0; | |
140 | while (*opts) { | |
141 | if (*opts == '"') | |
142 | break; | |
143 | if (*opts == '\\' && opts[1] == '"') { | |
144 | opts += 2; | |
145 | s[i++] = '"'; | |
146 | continue; | |
147 | } | |
148 | s[i++] = *opts++; | |
149 | } | |
150 | if (!*opts) { | |
151 | debug("%.100s, line %lu: missing end quote", | |
152 | file, linenum); | |
153 | packet_send_debug("%.100s, line %lu: missing end quote", | |
154 | file, linenum); | |
155 | xfree(s); | |
156 | goto bad_option; | |
157 | } | |
158 | s[i] = 0; | |
159 | packet_send_debug("Adding to environment: %.900s", s); | |
160 | debug("Adding to environment: %.900s", s); | |
161 | opts++; | |
162 | new_envstring = xmalloc(sizeof(struct envstring)); | |
163 | new_envstring->s = s; | |
164 | new_envstring->next = custom_environment; | |
165 | custom_environment = new_envstring; | |
166 | goto next_option; | |
167 | } | |
168 | cp = "from=\""; | |
169 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
170 | int mname, mip; | |
171 | const char *remote_ip = get_remote_ipaddr(); | |
172 | const char *remote_host = get_canonical_hostname( | |
173 | options.reverse_mapping_check); | |
174 | char *patterns = xmalloc(strlen(opts) + 1); | |
175 | ||
176 | opts += strlen(cp); | |
177 | i = 0; | |
178 | while (*opts) { | |
179 | if (*opts == '"') | |
180 | break; | |
181 | if (*opts == '\\' && opts[1] == '"') { | |
182 | opts += 2; | |
183 | patterns[i++] = '"'; | |
184 | continue; | |
185 | } | |
186 | patterns[i++] = *opts++; | |
187 | } | |
188 | if (!*opts) { | |
189 | debug("%.100s, line %lu: missing end quote", | |
190 | file, linenum); | |
191 | packet_send_debug("%.100s, line %lu: missing end quote", | |
192 | file, linenum); | |
193 | xfree(patterns); | |
194 | goto bad_option; | |
195 | } | |
196 | patterns[i] = 0; | |
197 | opts++; | |
198 | /* | |
199 | * Deny access if we get a negative | |
200 | * match for the hostname or the ip | |
201 | * or if we get not match at all | |
202 | */ | |
203 | mname = match_hostname(remote_host, patterns, | |
204 | strlen(patterns)); | |
205 | mip = match_hostname(remote_ip, patterns, | |
206 | strlen(patterns)); | |
207 | xfree(patterns); | |
208 | if (mname == -1 || mip == -1 || | |
209 | (mname != 1 && mip != 1)) { | |
210 | log("Authentication tried for %.100s with " | |
211 | "correct key but not from a permitted " | |
212 | "host (host=%.200s, ip=%.200s).", | |
213 | pw->pw_name, remote_host, remote_ip); | |
214 | packet_send_debug("Your host '%.200s' is not " | |
215 | "permitted to use this key for login.", | |
216 | remote_host); | |
217 | /* deny access */ | |
218 | return 0; | |
219 | } | |
220 | /* Host name matches. */ | |
221 | goto next_option; | |
222 | } | |
223 | cp = "permitopen=\""; | |
224 | if (strncasecmp(opts, cp, strlen(cp)) == 0) { | |
225 | u_short port; | |
226 | char *c, *ep; | |
227 | char *patterns = xmalloc(strlen(opts) + 1); | |
228 | ||
229 | opts += strlen(cp); | |
230 | i = 0; | |
231 | while (*opts) { | |
232 | if (*opts == '"') | |
233 | break; | |
234 | if (*opts == '\\' && opts[1] == '"') { | |
235 | opts += 2; | |
236 | patterns[i++] = '"'; | |
237 | continue; | |
238 | } | |
239 | patterns[i++] = *opts++; | |
240 | } | |
241 | if (!*opts) { | |
242 | debug("%.100s, line %lu: missing end quote", | |
243 | file, linenum); | |
244 | packet_send_debug("%.100s, line %lu: missing end quote", | |
245 | file, linenum); | |
246 | xfree(patterns); | |
247 | goto bad_option; | |
248 | } | |
249 | patterns[i] = 0; | |
250 | opts++; | |
251 | c = strchr(patterns, ':'); | |
252 | if (c == NULL) { | |
253 | debug("%.100s, line %lu: permitopen: missing colon <%.100s>", | |
254 | file, linenum, patterns); | |
255 | packet_send_debug("%.100s, line %lu: missing colon", | |
256 | file, linenum); | |
257 | xfree(patterns); | |
258 | goto bad_option; | |
259 | } | |
260 | *c = 0; | |
261 | c++; | |
262 | port = strtol(c, &ep, 0); | |
263 | if (c == ep) { | |
264 | debug("%.100s, line %lu: permitopen: missing port <%.100s>", | |
265 | file, linenum, patterns); | |
266 | packet_send_debug("%.100s, line %lu: missing port", | |
267 | file, linenum); | |
268 | xfree(patterns); | |
269 | goto bad_option; | |
270 | } | |
271 | channel_add_permitted_opens(patterns, port); | |
272 | xfree(patterns); | |
273 | goto next_option; | |
274 | } | |
275 | next_option: | |
276 | /* | |
277 | * Skip the comma, and move to the next option | |
278 | * (or break out if there are no more). | |
279 | */ | |
280 | if (!*opts) | |
281 | fatal("Bugs in auth-options.c option processing."); | |
282 | if (*opts == ' ' || *opts == '\t') | |
283 | break; /* End of options. */ | |
284 | if (*opts != ',') | |
285 | goto bad_option; | |
286 | opts++; | |
287 | /* Process the next option. */ | |
288 | } | |
289 | /* grant access */ | |
290 | return 1; | |
291 | ||
292 | bad_option: | |
293 | log("Bad options in %.100s file, line %lu: %.50s", | |
294 | file, linenum, opts); | |
295 | packet_send_debug("Bad options in %.100s file, line %lu: %.50s", | |
296 | file, linenum, opts); | |
297 | /* deny access */ | |
298 | return 0; | |
299 | } |