[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 1.28 2003/06/02 09:17:34 markus 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;

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;
	}
	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[256], sport[6];
			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++;
			if (sscanf(patterns, "%255[^:]:%5[0-9]", host, sport) != 2 &&
			    sscanf(patterns, "%255[^/]/%5[0-9]", host, sport) != 2) {
				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;
			}
			if ((port = a2port(sport)) == 0) {
				debug("%.100s, line %lu: Bad permitopen port <%.100s>",
				    file, linenum, sport);
				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;
		}
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"
c5a7d788	13	RCSID("$OpenBSD: auth-options.c,v 1.28 2003/06/02 09:17:34 markus 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
61e96248	38	extern ServerOptions options;
61e96248	39
94ec8c6b	40	void
	41	auth_clear_options(void)
	42	{
	43	no_agent_forwarding_flag = 0;
	44	no_port_forwarding_flag = 0;
	45	no_pty_flag = 0;
	46	no_x11_forwarding_flag = 0;
	47	while (custom_environment) {
	48	struct envstring *ce = custom_environment;
	49	custom_environment = ce->next;
	50	xfree(ce->s);
	51	xfree(ce);
	52	}
	53	if (forced_command) {
	54	xfree(forced_command);
	55	forced_command = NULL;
	56	}
01794848	57	channel_clear_permitted_opens();
01dafcb5	58	auth_debug_reset();
94ec8c6b	59	}
94ec8c6b	60
42f11eb2	61	/*
	62	* return 1 if access is granted, 0 if not.
	63	* side effect: sets key option flags
	64	*/
38c295d6	65	int
61e96248	66	auth_parse_options(struct passwd pw, char opts, char *file, u_long linenum)
38c295d6	67	{
38c295d6	68	const char *cp;
01794848	69	int i;
94ec8c6b	70
	71	/* reset options */
	72	auth_clear_options();
	73
e0b2cf6b	74	if (!opts)
	75	return 1;
	76
61e96248	77	while (opts && opts != ' ' && *opts != '\t') {
38c295d6	78	cp = "no-port-forwarding";
61e96248	79	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	80	auth_debug_add("Port forwarding disabled.");
38c295d6	81	no_port_forwarding_flag = 1;
61e96248	82	opts += strlen(cp);
38c295d6	83	goto next_option;
	84	}
	85	cp = "no-agent-forwarding";
61e96248	86	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	87	auth_debug_add("Agent forwarding disabled.");
38c295d6	88	no_agent_forwarding_flag = 1;
61e96248	89	opts += strlen(cp);
38c295d6	90	goto next_option;
	91	}
	92	cp = "no-X11-forwarding";
61e96248	93	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	94	auth_debug_add("X11 forwarding disabled.");
38c295d6	95	no_x11_forwarding_flag = 1;
61e96248	96	opts += strlen(cp);
38c295d6	97	goto next_option;
	98	}
	99	cp = "no-pty";
61e96248	100	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	101	auth_debug_add("Pty allocation disabled.");
38c295d6	102	no_pty_flag = 1;
61e96248	103	opts += strlen(cp);
38c295d6	104	goto next_option;
	105	}
	106	cp = "command=\"";
61e96248	107	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	108	opts += strlen(cp);
61e96248	109	forced_command = xmalloc(strlen(opts) + 1);
38c295d6	110	i = 0;
61e96248	111	while (*opts) {
61e96248	112	if (*opts == '"')
38c295d6	113	break;
61e96248	114	if (*opts == '\\' && opts[1] == '"') {
61e96248	115	opts += 2;
38c295d6	116	forced_command[i++] = '"';
	117	continue;
	118	}
61e96248	119	forced_command[i++] = *opts++;
38c295d6	120	}
61e96248	121	if (!*opts) {
38c295d6	122	debug("%.100s, line %lu: missing end quote",
42f11eb2	123	file, linenum);
01dafcb5	124	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	125	file, linenum);
acc9d6d7	126	xfree(forced_command);
	127	forced_command = NULL;
	128	goto bad_option;
38c295d6	129	}
38c295d6	130	forced_command[i] = 0;
01dafcb5	131	auth_debug_add("Forced command: %.900s", forced_command);
61e96248	132	opts++;
38c295d6	133	goto next_option;
	134	}
	135	cp = "environment=\"";
f00bab84	136	if (options.permit_user_env &&
f00bab84	137	strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	138	char *s;
38c295d6	139	struct envstring *new_envstring;
01794848	140
61e96248	141	opts += strlen(cp);
61e96248	142	s = xmalloc(strlen(opts) + 1);
38c295d6	143	i = 0;
61e96248	144	while (*opts) {
61e96248	145	if (*opts == '"')
38c295d6	146	break;
61e96248	147	if (*opts == '\\' && opts[1] == '"') {
61e96248	148	opts += 2;
38c295d6	149	s[i++] = '"';
	150	continue;
	151	}
61e96248	152	s[i++] = *opts++;
38c295d6	153	}
61e96248	154	if (!*opts) {
38c295d6	155	debug("%.100s, line %lu: missing end quote",
42f11eb2	156	file, linenum);
01dafcb5	157	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	158	file, linenum);
acc9d6d7	159	xfree(s);
acc9d6d7	160	goto bad_option;
38c295d6	161	}
38c295d6	162	s[i] = 0;
01dafcb5	163	auth_debug_add("Adding to environment: %.900s", s);
38c295d6	164	debug("Adding to environment: %.900s", s);
61e96248	165	opts++;
38c295d6	166	new_envstring = xmalloc(sizeof(struct envstring));
	167	new_envstring->s = s;
	168	new_envstring->next = custom_environment;
	169	custom_environment = new_envstring;
	170	goto next_option;
	171	}
	172	cp = "from=\"";
61e96248	173	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	174	const char *remote_ip = get_remote_ipaddr();
61e96248	175	const char *remote_host = get_canonical_hostname(
c5a7d788	176	options.use_dns);
61e96248	177	char *patterns = xmalloc(strlen(opts) + 1);
01794848	178
61e96248	179	opts += strlen(cp);
38c295d6	180	i = 0;
61e96248	181	while (*opts) {
61e96248	182	if (*opts == '"')
38c295d6	183	break;
61e96248	184	if (*opts == '\\' && opts[1] == '"') {
61e96248	185	opts += 2;
38c295d6	186	patterns[i++] = '"';
	187	continue;
	188	}
61e96248	189	patterns[i++] = *opts++;
38c295d6	190	}
61e96248	191	if (!*opts) {
38c295d6	192	debug("%.100s, line %lu: missing end quote",
42f11eb2	193	file, linenum);
01dafcb5	194	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	195	file, linenum);
acc9d6d7	196	xfree(patterns);
acc9d6d7	197	goto bad_option;
38c295d6	198	}
38c295d6	199	patterns[i] = 0;
61e96248	200	opts++;
2cee8a25	201	if (match_host_and_ip(remote_host, remote_ip,
	202	patterns) != 1) {
	203	xfree(patterns);
bbe88b6d	204	logit("Authentication tried for %.100s with "
61e96248	205	"correct key but not from a permitted "
	206	"host (host=%.200s, ip=%.200s).",
	207	pw->pw_name, remote_host, remote_ip);
01dafcb5	208	auth_debug_add("Your host '%.200s' is not "
61e96248	209	"permitted to use this key for login.",
61e96248	210	remote_host);
38c295d6	211	/* deny access */
	212	return 0;
	213	}
2cee8a25	214	xfree(patterns);
38c295d6	215	/* Host name matches. */
	216	goto next_option;
	217	}
01794848	218	cp = "permitopen=\"";
01794848	219	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
ed787d14	220	char host[256], sport[6];
01794848	221	u_short port;
01794848	222	char *patterns = xmalloc(strlen(opts) + 1);
	223
	224	opts += strlen(cp);
	225	i = 0;
	226	while (*opts) {
	227	if (*opts == '"')
	228	break;
	229	if (*opts == '\\' && opts[1] == '"') {
	230	opts += 2;
	231	patterns[i++] = '"';
	232	continue;
	233	}
	234	patterns[i++] = *opts++;
	235	}
	236	if (!*opts) {
	237	debug("%.100s, line %lu: missing end quote",
	238	file, linenum);
01dafcb5	239	auth_debug_add("%.100s, line %lu: missing end quote",
01794848	240	file, linenum);
	241	xfree(patterns);
	242	goto bad_option;
	243	}
	244	patterns[i] = 0;
	245	opts++;
ed787d14	246	if (sscanf(patterns, "%255[^:]:%5[0-9]", host, sport) != 2 &&
	247	sscanf(patterns, "%255[^/]/%5[0-9]", host, sport) != 2) {
	248	debug("%.100s, line %lu: Bad permitopen specification "
	249	"<%.100s>", file, linenum, patterns);
01dafcb5	250	auth_debug_add("%.100s, line %lu: "
ed787d14	251	"Bad permitopen specification", file, linenum);
01794848	252	xfree(patterns);
	253	goto bad_option;
	254	}
ed787d14	255	if ((port = a2port(sport)) == 0) {
	256	debug("%.100s, line %lu: Bad permitopen port <%.100s>",
	257	file, linenum, sport);
01dafcb5	258	auth_debug_add("%.100s, line %lu: "
ed787d14	259	"Bad permitopen port", file, linenum);
01794848	260	xfree(patterns);
	261	goto bad_option;
	262	}
b1ed8313	263	if (options.allow_tcp_forwarding)
ed787d14	264	channel_add_permitted_opens(host, port);
01794848	265	xfree(patterns);
	266	goto next_option;
	267	}
38c295d6	268	next_option:
	269	/*
	270	* Skip the comma, and move to the next option
	271	* (or break out if there are no more).
	272	*/
61e96248	273	if (!*opts)
38c295d6	274	fatal("Bugs in auth-options.c option processing.");
61e96248	275	if (opts == ' ' \|\| opts == '\t')
38c295d6	276	break; /* End of options. */
61e96248	277	if (*opts != ',')
38c295d6	278	goto bad_option;
61e96248	279	opts++;
38c295d6	280	/* Process the next option. */
38c295d6	281	}
1853d1ef	282
1853d1ef	283	if (!use_privsep)
01dafcb5	284	auth_debug_send();
1853d1ef	285
38c295d6	286	/* grant access */
	287	return 1;
	288
	289	bad_option:
bbe88b6d	290	logit("Bad options in %.100s file, line %lu: %.50s",
61e96248	291	file, linenum, opts);
01dafcb5	292	auth_debug_add("Bad options in %.100s file, line %lu: %.50s",
61e96248	293	file, linenum, opts);
1853d1ef	294
1853d1ef	295	if (!use_privsep)
01dafcb5	296	auth_debug_send();
1853d1ef	297
38c295d6	298	/* deny access */
	299	return 0;
	300	}