[openssh.git] / auth-options.c

/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 */

#include "includes.h"
RCSID("$OpenBSD: auth-options.c,v 1.33 2005/12/08 18:34:11 reyk Exp $");

#include "xmalloc.h"
#include "match.h"
#include "log.h"
#include "canohost.h"
#include "channels.h"
#include "auth-options.h"
#include "servconf.h"
#include "misc.h"
#include "monitor_wrap.h"
#include "auth.h"

/* Flags set authorized_keys flags */
int no_port_forwarding_flag = 0;
int no_agent_forwarding_flag = 0;
int no_x11_forwarding_flag = 0;
int no_pty_flag = 0;

/* "command=" option. */
char *forced_command = NULL;

/* "environment=" options. */
struct envstring *custom_environment = NULL;

/* "tunnel=" option. */
int forced_tun_device = -1;

extern ServerOptions options;

void
auth_clear_options(void)
{
	no_agent_forwarding_flag = 0;
	no_port_forwarding_flag = 0;
	no_pty_flag = 0;
	no_x11_forwarding_flag = 0;
	while (custom_environment) {
		struct envstring *ce = custom_environment;
		custom_environment = ce->next;
		xfree(ce->s);
		xfree(ce);
	}
	if (forced_command) {
		xfree(forced_command);
		forced_command = NULL;
	}
	forced_tun_device = -1;
	channel_clear_permitted_opens();
	auth_debug_reset();
}

/*
 * return 1 if access is granted, 0 if not.
 * side effect: sets key option flags
 */
int
auth_parse_options(struct passwd *pw, char *opts, char *file, u_long linenum)
{
	const char *cp;
	int i;

	/* reset options */
	auth_clear_options();

	if (!opts)
		return 1;

	while (*opts && *opts != ' ' && *opts != '\t') {
		cp = "no-port-forwarding";
		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
			auth_debug_add("Port forwarding disabled.");
			no_port_forwarding_flag = 1;
			opts += strlen(cp);
			goto next_option;
		}
		cp = "no-agent-forwarding";
		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
			auth_debug_add("Agent forwarding disabled.");
			no_agent_forwarding_flag = 1;
			opts += strlen(cp);
			goto next_option;
		}
		cp = "no-X11-forwarding";
		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
			auth_debug_add("X11 forwarding disabled.");
			no_x11_forwarding_flag = 1;
			opts += strlen(cp);
			goto next_option;
		}
		cp = "no-pty";
		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
			auth_debug_add("Pty allocation disabled.");
			no_pty_flag = 1;
			opts += strlen(cp);
			goto next_option;
		}
		cp = "command=\"";
		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
			opts += strlen(cp);
			forced_command = xmalloc(strlen(opts) + 1);
			i = 0;
			while (*opts) {
				if (*opts == '"')
					break;
				if (*opts == '\\' && opts[1] == '"') {
					opts += 2;
					forced_command[i++] = '"';
					continue;
				}
				forced_command[i++] = *opts++;
			}
			if (!*opts) {
				debug("%.100s, line %lu: missing end quote",
				    file, linenum);
				auth_debug_add("%.100s, line %lu: missing end quote",
				    file, linenum);
				xfree(forced_command);
				forced_command = NULL;
				goto bad_option;
			}
			forced_command[i] = 0;
			auth_debug_add("Forced command: %.900s", forced_command);
			opts++;
			goto next_option;
		}
		cp = "environment=\"";
		if (options.permit_user_env &&
		    strncasecmp(opts, cp, strlen(cp)) == 0) {
			char *s;
			struct envstring *new_envstring;

			opts += strlen(cp);
			s = xmalloc(strlen(opts) + 1);
			i = 0;
			while (*opts) {
				if (*opts == '"')
					break;
				if (*opts == '\\' && opts[1] == '"') {
					opts += 2;
					s[i++] = '"';
					continue;
				}
				s[i++] = *opts++;
			}
			if (!*opts) {
				debug("%.100s, line %lu: missing end quote",
				    file, linenum);
				auth_debug_add("%.100s, line %lu: missing end quote",
				    file, linenum);
				xfree(s);
				goto bad_option;
			}
			s[i] = 0;
			auth_debug_add("Adding to environment: %.900s", s);
			debug("Adding to environment: %.900s", s);
			opts++;
			new_envstring = xmalloc(sizeof(struct envstring));
			new_envstring->s = s;
			new_envstring->next = custom_environment;
			custom_environment = new_envstring;
			goto next_option;
		}
		cp = "from=\"";
		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
			const char *remote_ip = get_remote_ipaddr();
			const char *remote_host = get_canonical_hostname(
			    options.use_dns);
			char *patterns = xmalloc(strlen(opts) + 1);

			opts += strlen(cp);
			i = 0;
			while (*opts) {
				if (*opts == '"')
					break;
				if (*opts == '\\' && opts[1] == '"') {
					opts += 2;
					patterns[i++] = '"';
					continue;
				}
				patterns[i++] = *opts++;
			}
			if (!*opts) {
				debug("%.100s, line %lu: missing end quote",
				    file, linenum);
				auth_debug_add("%.100s, line %lu: missing end quote",
				    file, linenum);
				xfree(patterns);
				goto bad_option;
			}
			patterns[i] = 0;
			opts++;
			if (match_host_and_ip(remote_host, remote_ip,
			    patterns) != 1) {
				xfree(patterns);
				logit("Authentication tried for %.100s with "
				    "correct key but not from a permitted "
				    "host (host=%.200s, ip=%.200s).",
				    pw->pw_name, remote_host, remote_ip);
				auth_debug_add("Your host '%.200s' is not "
				    "permitted to use this key for login.",
				    remote_host);
				/* deny access */
				return 0;
			}
			xfree(patterns);
			/* Host name matches. */
			goto next_option;
		}
		cp = "permitopen=\"";
		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
			char *host, *p;
			u_short port;
			char *patterns = xmalloc(strlen(opts) + 1);

			opts += strlen(cp);
			i = 0;
			while (*opts) {
				if (*opts == '"')
					break;
				if (*opts == '\\' && opts[1] == '"') {
					opts += 2;
					patterns[i++] = '"';
					continue;
				}
				patterns[i++] = *opts++;
			}
			if (!*opts) {
				debug("%.100s, line %lu: missing end quote",
				    file, linenum);
				auth_debug_add("%.100s, line %lu: missing "
				    "end quote", file, linenum);
				xfree(patterns);
				goto bad_option;
			}
			patterns[i] = 0;
			opts++;
			p = patterns;
			host = hpdelim(&p);
			if (host == NULL || strlen(host) >= NI_MAXHOST) {
				debug("%.100s, line %lu: Bad permitopen "
				    "specification <%.100s>", file, linenum,
				    patterns);
				auth_debug_add("%.100s, line %lu: "
				    "Bad permitopen specification", file,
				    linenum);
				xfree(patterns);
				goto bad_option;
			}
			host = cleanhostname(host);
			if (p == NULL || (port = a2port(p)) == 0) {
				debug("%.100s, line %lu: Bad permitopen port "
				    "<%.100s>", file, linenum, p ? p : "");
				auth_debug_add("%.100s, line %lu: "
				    "Bad permitopen port", file, linenum);
				xfree(patterns);
				goto bad_option;
			}
			if (options.allow_tcp_forwarding)
				channel_add_permitted_opens(host, port);
			xfree(patterns);
			goto next_option;
		}
		cp = "tunnel=\"";
		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
			char *tun = NULL;
			opts += strlen(cp);
			tun = xmalloc(strlen(opts) + 1);
			i = 0;
			while (*opts) {
				if (*opts == '"')
					break;
				tun[i++] = *opts++;
			}
			if (!*opts) {
				debug("%.100s, line %lu: missing end quote",
				    file, linenum);
				auth_debug_add("%.100s, line %lu: missing end quote",
				    file, linenum);
				xfree(tun);
				forced_tun_device = -1;
				goto bad_option;
			}
			tun[i] = 0;
			forced_tun_device = a2tun(tun, NULL);
			xfree(tun);
			if (forced_tun_device == SSH_TUNID_ERR) {
				debug("%.100s, line %lu: invalid tun device",
				    file, linenum);
				auth_debug_add("%.100s, line %lu: invalid tun device",
				    file, linenum);
				forced_tun_device = -1;
				goto bad_option;
			}
			auth_debug_add("Forced tun device: %d", forced_tun_device);
			opts++;
			goto next_option;
		}
next_option:
		/*
		 * Skip the comma, and move to the next option
		 * (or break out if there are no more).
		 */
		if (!*opts)
			fatal("Bugs in auth-options.c option processing.");
		if (*opts == ' ' || *opts == '\t')
			break;		/* End of options. */
		if (*opts != ',')
			goto bad_option;
		opts++;
		/* Process the next option. */
	}

	if (!use_privsep)
		auth_debug_send();

	/* grant access */
	return 1;

bad_option:
	logit("Bad options in %.100s file, line %lu: %.50s",
	    file, linenum, opts);
	auth_debug_add("Bad options in %.100s file, line %lu: %.50s",
	    file, linenum, opts);

	if (!use_privsep)
		auth_debug_send();

	/* deny access */
	return 0;
}
Commit	Line	Data
bcbf86ec	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
bcbf86ec	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
38c295d6	12	#include "includes.h"
a4f24bf8	13	RCSID("$OpenBSD: auth-options.c,v 1.33 2005/12/08 18:34:11 reyk Exp $");
38c295d6	14
38c295d6	15	#include "xmalloc.h"
38c295d6	16	#include "match.h"
42f11eb2	17	#include "log.h"
42f11eb2	18	#include "canohost.h"
a5efa1bb	19	#include "channels.h"
42f11eb2	20	#include "auth-options.h"
61e96248	21	#include "servconf.h"
ed787d14	22	#include "misc.h"
1853d1ef	23	#include "monitor_wrap.h"
01dafcb5	24	#include "auth.h"
38c295d6	25
	26	/* Flags set authorized_keys flags */
	27	int no_port_forwarding_flag = 0;
	28	int no_agent_forwarding_flag = 0;
	29	int no_x11_forwarding_flag = 0;
	30	int no_pty_flag = 0;
	31
	32	/* "command=" option. */
	33	char *forced_command = NULL;
	34
	35	/* "environment=" options. */
	36	struct envstring *custom_environment = NULL;
	37
d20f3c9e	38	/* "tunnel=" option. */
	39	int forced_tun_device = -1;
	40
61e96248	41	extern ServerOptions options;
61e96248	42
94ec8c6b	43	void
	44	auth_clear_options(void)
	45	{
	46	no_agent_forwarding_flag = 0;
	47	no_port_forwarding_flag = 0;
	48	no_pty_flag = 0;
	49	no_x11_forwarding_flag = 0;
	50	while (custom_environment) {
	51	struct envstring *ce = custom_environment;
	52	custom_environment = ce->next;
	53	xfree(ce->s);
	54	xfree(ce);
	55	}
	56	if (forced_command) {
	57	xfree(forced_command);
	58	forced_command = NULL;
	59	}
d20f3c9e	60	forced_tun_device = -1;
01794848	61	channel_clear_permitted_opens();
01dafcb5	62	auth_debug_reset();
94ec8c6b	63	}
94ec8c6b	64
42f11eb2	65	/*
	66	* return 1 if access is granted, 0 if not.
	67	* side effect: sets key option flags
	68	*/
38c295d6	69	int
61e96248	70	auth_parse_options(struct passwd pw, char opts, char *file, u_long linenum)
38c295d6	71	{
38c295d6	72	const char *cp;
01794848	73	int i;
94ec8c6b	74
	75	/* reset options */
	76	auth_clear_options();
	77
e0b2cf6b	78	if (!opts)
	79	return 1;
	80
61e96248	81	while (opts && opts != ' ' && *opts != '\t') {
38c295d6	82	cp = "no-port-forwarding";
61e96248	83	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	84	auth_debug_add("Port forwarding disabled.");
38c295d6	85	no_port_forwarding_flag = 1;
61e96248	86	opts += strlen(cp);
38c295d6	87	goto next_option;
	88	}
	89	cp = "no-agent-forwarding";
61e96248	90	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	91	auth_debug_add("Agent forwarding disabled.");
38c295d6	92	no_agent_forwarding_flag = 1;
61e96248	93	opts += strlen(cp);
38c295d6	94	goto next_option;
	95	}
	96	cp = "no-X11-forwarding";
61e96248	97	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	98	auth_debug_add("X11 forwarding disabled.");
38c295d6	99	no_x11_forwarding_flag = 1;
61e96248	100	opts += strlen(cp);
38c295d6	101	goto next_option;
	102	}
	103	cp = "no-pty";
61e96248	104	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	105	auth_debug_add("Pty allocation disabled.");
38c295d6	106	no_pty_flag = 1;
61e96248	107	opts += strlen(cp);
38c295d6	108	goto next_option;
	109	}
	110	cp = "command=\"";
61e96248	111	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	112	opts += strlen(cp);
61e96248	113	forced_command = xmalloc(strlen(opts) + 1);
38c295d6	114	i = 0;
61e96248	115	while (*opts) {
61e96248	116	if (*opts == '"')
38c295d6	117	break;
61e96248	118	if (*opts == '\\' && opts[1] == '"') {
61e96248	119	opts += 2;
38c295d6	120	forced_command[i++] = '"';
	121	continue;
	122	}
61e96248	123	forced_command[i++] = *opts++;
38c295d6	124	}
61e96248	125	if (!*opts) {
38c295d6	126	debug("%.100s, line %lu: missing end quote",
42f11eb2	127	file, linenum);
01dafcb5	128	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	129	file, linenum);
acc9d6d7	130	xfree(forced_command);
	131	forced_command = NULL;
	132	goto bad_option;
38c295d6	133	}
38c295d6	134	forced_command[i] = 0;
01dafcb5	135	auth_debug_add("Forced command: %.900s", forced_command);
61e96248	136	opts++;
38c295d6	137	goto next_option;
	138	}
	139	cp = "environment=\"";
f00bab84	140	if (options.permit_user_env &&
f00bab84	141	strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	142	char *s;
38c295d6	143	struct envstring *new_envstring;
01794848	144
61e96248	145	opts += strlen(cp);
61e96248	146	s = xmalloc(strlen(opts) + 1);
38c295d6	147	i = 0;
61e96248	148	while (*opts) {
61e96248	149	if (*opts == '"')
38c295d6	150	break;
61e96248	151	if (*opts == '\\' && opts[1] == '"') {
61e96248	152	opts += 2;
38c295d6	153	s[i++] = '"';
	154	continue;
	155	}
61e96248	156	s[i++] = *opts++;
38c295d6	157	}
61e96248	158	if (!*opts) {
38c295d6	159	debug("%.100s, line %lu: missing end quote",
42f11eb2	160	file, linenum);
01dafcb5	161	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	162	file, linenum);
acc9d6d7	163	xfree(s);
acc9d6d7	164	goto bad_option;
38c295d6	165	}
38c295d6	166	s[i] = 0;
01dafcb5	167	auth_debug_add("Adding to environment: %.900s", s);
38c295d6	168	debug("Adding to environment: %.900s", s);
61e96248	169	opts++;
38c295d6	170	new_envstring = xmalloc(sizeof(struct envstring));
	171	new_envstring->s = s;
	172	new_envstring->next = custom_environment;
	173	custom_environment = new_envstring;
	174	goto next_option;
	175	}
	176	cp = "from=\"";
61e96248	177	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	178	const char *remote_ip = get_remote_ipaddr();
61e96248	179	const char *remote_host = get_canonical_hostname(
c5a7d788	180	options.use_dns);
61e96248	181	char *patterns = xmalloc(strlen(opts) + 1);
01794848	182
61e96248	183	opts += strlen(cp);
38c295d6	184	i = 0;
61e96248	185	while (*opts) {
61e96248	186	if (*opts == '"')
38c295d6	187	break;
61e96248	188	if (*opts == '\\' && opts[1] == '"') {
61e96248	189	opts += 2;
38c295d6	190	patterns[i++] = '"';
	191	continue;
	192	}
61e96248	193	patterns[i++] = *opts++;
38c295d6	194	}
61e96248	195	if (!*opts) {
38c295d6	196	debug("%.100s, line %lu: missing end quote",
42f11eb2	197	file, linenum);
01dafcb5	198	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	199	file, linenum);
acc9d6d7	200	xfree(patterns);
acc9d6d7	201	goto bad_option;
38c295d6	202	}
38c295d6	203	patterns[i] = 0;
61e96248	204	opts++;
2cee8a25	205	if (match_host_and_ip(remote_host, remote_ip,
	206	patterns) != 1) {
	207	xfree(patterns);
bbe88b6d	208	logit("Authentication tried for %.100s with "
61e96248	209	"correct key but not from a permitted "
	210	"host (host=%.200s, ip=%.200s).",
	211	pw->pw_name, remote_host, remote_ip);
01dafcb5	212	auth_debug_add("Your host '%.200s' is not "
61e96248	213	"permitted to use this key for login.",
61e96248	214	remote_host);
38c295d6	215	/* deny access */
	216	return 0;
	217	}
2cee8a25	218	xfree(patterns);
38c295d6	219	/* Host name matches. */
	220	goto next_option;
	221	}
01794848	222	cp = "permitopen=\"";
01794848	223	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
3867aa0a	224	char host, p;
01794848	225	u_short port;
01794848	226	char *patterns = xmalloc(strlen(opts) + 1);
	227
	228	opts += strlen(cp);
	229	i = 0;
	230	while (*opts) {
	231	if (*opts == '"')
	232	break;
	233	if (*opts == '\\' && opts[1] == '"') {
	234	opts += 2;
	235	patterns[i++] = '"';
	236	continue;
	237	}
	238	patterns[i++] = *opts++;
	239	}
	240	if (!*opts) {
	241	debug("%.100s, line %lu: missing end quote",
	242	file, linenum);
3867aa0a	243	auth_debug_add("%.100s, line %lu: missing "
3867aa0a	244	"end quote", file, linenum);
01794848	245	xfree(patterns);
	246	goto bad_option;
	247	}
	248	patterns[i] = 0;
	249	opts++;
3867aa0a	250	p = patterns;
	251	host = hpdelim(&p);
	252	if (host == NULL \|\| strlen(host) >= NI_MAXHOST) {
	253	debug("%.100s, line %lu: Bad permitopen "
16d3d2bc	254	"specification <%.100s>", file, linenum,
3867aa0a	255	patterns);
01dafcb5	256	auth_debug_add("%.100s, line %lu: "
3867aa0a	257	"Bad permitopen specification", file,
3867aa0a	258	linenum);
01794848	259	xfree(patterns);
	260	goto bad_option;
	261	}
f8cc7664	262	host = cleanhostname(host);
f8cc7664	263	if (p == NULL \|\| (port = a2port(p)) == 0) {
3867aa0a	264	debug("%.100s, line %lu: Bad permitopen port "
3867aa0a	265	"<%.100s>", file, linenum, p ? p : "");
01dafcb5	266	auth_debug_add("%.100s, line %lu: "
ed787d14	267	"Bad permitopen port", file, linenum);
01794848	268	xfree(patterns);
	269	goto bad_option;
	270	}
b1ed8313	271	if (options.allow_tcp_forwarding)
ed787d14	272	channel_add_permitted_opens(host, port);
01794848	273	xfree(patterns);
	274	goto next_option;
	275	}
d20f3c9e	276	cp = "tunnel=\"";
	277	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	278	char *tun = NULL;
	279	opts += strlen(cp);
	280	tun = xmalloc(strlen(opts) + 1);
	281	i = 0;
	282	while (*opts) {
	283	if (*opts == '"')
	284	break;
	285	tun[i++] = *opts++;
	286	}
	287	if (!*opts) {
	288	debug("%.100s, line %lu: missing end quote",
	289	file, linenum);
	290	auth_debug_add("%.100s, line %lu: missing end quote",
	291	file, linenum);
	292	xfree(tun);
	293	forced_tun_device = -1;
	294	goto bad_option;
	295	}
	296	tun[i] = 0;
	297	forced_tun_device = a2tun(tun, NULL);
	298	xfree(tun);
a4f24bf8	299	if (forced_tun_device == SSH_TUNID_ERR) {
d20f3c9e	300	debug("%.100s, line %lu: invalid tun device",
	301	file, linenum);
	302	auth_debug_add("%.100s, line %lu: invalid tun device",
	303	file, linenum);
	304	forced_tun_device = -1;
	305	goto bad_option;
	306	}
	307	auth_debug_add("Forced tun device: %d", forced_tun_device);
	308	opts++;
	309	goto next_option;
	310	}
38c295d6	311	next_option:
	312	/*
	313	* Skip the comma, and move to the next option
	314	* (or break out if there are no more).
	315	*/
61e96248	316	if (!*opts)
38c295d6	317	fatal("Bugs in auth-options.c option processing.");
61e96248	318	if (opts == ' ' \|\| opts == '\t')
38c295d6	319	break; /* End of options. */
61e96248	320	if (*opts != ',')
38c295d6	321	goto bad_option;
61e96248	322	opts++;
38c295d6	323	/* Process the next option. */
38c295d6	324	}
1853d1ef	325
1853d1ef	326	if (!use_privsep)
01dafcb5	327	auth_debug_send();
1853d1ef	328
38c295d6	329	/* grant access */
	330	return 1;
	331
	332	bad_option:
bbe88b6d	333	logit("Bad options in %.100s file, line %lu: %.50s",
61e96248	334	file, linenum, opts);
01dafcb5	335	auth_debug_add("Bad options in %.100s file, line %lu: %.50s",
61e96248	336	file, linenum, opts);
1853d1ef	337
1853d1ef	338	if (!use_privsep)
01dafcb5	339	auth_debug_send();
1853d1ef	340
38c295d6	341	/* deny access */
	342	return 0;
	343	}