Annotation of src/usr.bin/ssh/auth-options.c, Revision 1.18
1.3 deraadt 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:
1.1 markus 12: #include "includes.h"
1.18 ! markus 13: RCSID("$OpenBSD: auth-options.c,v 1.17 2001/05/30 12:55:06 markus Exp $");
1.1 markus 14:
15: #include "packet.h"
16: #include "xmalloc.h"
17: #include "match.h"
1.11 markus 18: #include "log.h"
19: #include "canohost.h"
1.18 ! markus 20: #include "channels.h"
1.11 markus 21: #include "auth-options.h"
1.12 markus 22: #include "servconf.h"
1.1 markus 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:
1.12 markus 36: extern ServerOptions options;
37:
1.5 markus 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: }
1.15 markus 55: channel_clear_permitted_opens();
1.5 markus 56: }
57:
1.10 markus 58: /*
59: * return 1 if access is granted, 0 if not.
60: * side effect: sets key option flags
61: */
1.1 markus 62: int
1.12 markus 63: auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum)
1.1 markus 64: {
65: const char *cp;
1.15 markus 66: int i;
1.5 markus 67:
68: /* reset options */
69: auth_clear_options();
1.13 markus 70:
71: if (!opts)
72: return 1;
1.5 markus 73:
1.12 markus 74: while (*opts && *opts != ' ' && *opts != '\t') {
1.1 markus 75: cp = "no-port-forwarding";
1.12 markus 76: if (strncasecmp(opts, cp, strlen(cp)) == 0) {
1.1 markus 77: packet_send_debug("Port forwarding disabled.");
78: no_port_forwarding_flag = 1;
1.12 markus 79: opts += strlen(cp);
1.1 markus 80: goto next_option;
81: }
82: cp = "no-agent-forwarding";
1.12 markus 83: if (strncasecmp(opts, cp, strlen(cp)) == 0) {
1.1 markus 84: packet_send_debug("Agent forwarding disabled.");
85: no_agent_forwarding_flag = 1;
1.12 markus 86: opts += strlen(cp);
1.1 markus 87: goto next_option;
88: }
89: cp = "no-X11-forwarding";
1.12 markus 90: if (strncasecmp(opts, cp, strlen(cp)) == 0) {
1.1 markus 91: packet_send_debug("X11 forwarding disabled.");
92: no_x11_forwarding_flag = 1;
1.12 markus 93: opts += strlen(cp);
1.1 markus 94: goto next_option;
95: }
96: cp = "no-pty";
1.12 markus 97: if (strncasecmp(opts, cp, strlen(cp)) == 0) {
1.1 markus 98: packet_send_debug("Pty allocation disabled.");
99: no_pty_flag = 1;
1.12 markus 100: opts += strlen(cp);
1.1 markus 101: goto next_option;
102: }
103: cp = "command=\"";
1.12 markus 104: if (strncasecmp(opts, cp, strlen(cp)) == 0) {
105: opts += strlen(cp);
106: forced_command = xmalloc(strlen(opts) + 1);
1.1 markus 107: i = 0;
1.12 markus 108: while (*opts) {
109: if (*opts == '"')
1.1 markus 110: break;
1.12 markus 111: if (*opts == '\\' && opts[1] == '"') {
112: opts += 2;
1.1 markus 113: forced_command[i++] = '"';
114: continue;
115: }
1.12 markus 116: forced_command[i++] = *opts++;
1.1 markus 117: }
1.12 markus 118: if (!*opts) {
1.1 markus 119: debug("%.100s, line %lu: missing end quote",
1.10 markus 120: file, linenum);
1.1 markus 121: packet_send_debug("%.100s, line %lu: missing end quote",
1.10 markus 122: file, linenum);
1.14 markus 123: xfree(forced_command);
124: forced_command = NULL;
125: goto bad_option;
1.1 markus 126: }
127: forced_command[i] = 0;
128: packet_send_debug("Forced command: %.900s", forced_command);
1.12 markus 129: opts++;
1.1 markus 130: goto next_option;
131: }
132: cp = "environment=\"";
1.12 markus 133: if (strncasecmp(opts, cp, strlen(cp)) == 0) {
1.1 markus 134: char *s;
135: struct envstring *new_envstring;
1.15 markus 136:
1.12 markus 137: opts += strlen(cp);
138: s = xmalloc(strlen(opts) + 1);
1.1 markus 139: i = 0;
1.12 markus 140: while (*opts) {
141: if (*opts == '"')
1.1 markus 142: break;
1.12 markus 143: if (*opts == '\\' && opts[1] == '"') {
144: opts += 2;
1.1 markus 145: s[i++] = '"';
146: continue;
147: }
1.12 markus 148: s[i++] = *opts++;
1.1 markus 149: }
1.12 markus 150: if (!*opts) {
1.1 markus 151: debug("%.100s, line %lu: missing end quote",
1.10 markus 152: file, linenum);
1.1 markus 153: packet_send_debug("%.100s, line %lu: missing end quote",
1.10 markus 154: file, linenum);
1.14 markus 155: xfree(s);
156: goto bad_option;
1.1 markus 157: }
158: s[i] = 0;
159: packet_send_debug("Adding to environment: %.900s", s);
160: debug("Adding to environment: %.900s", s);
1.12 markus 161: opts++;
1.1 markus 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=\"";
1.12 markus 169: if (strncasecmp(opts, cp, strlen(cp)) == 0) {
1.1 markus 170: int mname, mip;
1.12 markus 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);
1.15 markus 175:
1.12 markus 176: opts += strlen(cp);
1.1 markus 177: i = 0;
1.12 markus 178: while (*opts) {
179: if (*opts == '"')
1.1 markus 180: break;
1.12 markus 181: if (*opts == '\\' && opts[1] == '"') {
182: opts += 2;
1.1 markus 183: patterns[i++] = '"';
184: continue;
185: }
1.12 markus 186: patterns[i++] = *opts++;
1.1 markus 187: }
1.12 markus 188: if (!*opts) {
1.1 markus 189: debug("%.100s, line %lu: missing end quote",
1.10 markus 190: file, linenum);
1.1 markus 191: packet_send_debug("%.100s, line %lu: missing end quote",
1.10 markus 192: file, linenum);
1.14 markus 193: xfree(patterns);
194: goto bad_option;
1.1 markus 195: }
196: patterns[i] = 0;
1.12 markus 197: opts++;
1.1 markus 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: */
1.12 markus 203: mname = match_hostname(remote_host, patterns,
204: strlen(patterns));
205: mip = match_hostname(remote_ip, patterns,
206: strlen(patterns));
1.1 markus 207: xfree(patterns);
208: if (mname == -1 || mip == -1 ||
209: (mname != 1 && mip != 1)) {
1.12 markus 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);
1.1 markus 217: /* deny access */
218: return 0;
219: }
220: /* Host name matches. */
1.15 markus 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: }
1.16 markus 271: if (options.allow_tcp_forwarding)
272: channel_add_permitted_opens(patterns, port);
1.15 markus 273: xfree(patterns);
1.1 markus 274: goto next_option;
275: }
276: next_option:
277: /*
278: * Skip the comma, and move to the next option
279: * (or break out if there are no more).
280: */
1.12 markus 281: if (!*opts)
1.1 markus 282: fatal("Bugs in auth-options.c option processing.");
1.12 markus 283: if (*opts == ' ' || *opts == '\t')
1.1 markus 284: break; /* End of options. */
1.12 markus 285: if (*opts != ',')
1.1 markus 286: goto bad_option;
1.12 markus 287: opts++;
1.1 markus 288: /* Process the next option. */
289: }
290: /* grant access */
291: return 1;
292:
293: bad_option:
294: log("Bad options in %.100s file, line %lu: %.50s",
1.12 markus 295: file, linenum, opts);
1.1 markus 296: packet_send_debug("Bad options in %.100s file, line %lu: %.50s",
1.12 markus 297: file, linenum, opts);
1.1 markus 298: /* deny access */
299: return 0;
300: }