[openssh.git] / auth-options.c

/* $OpenBSD: auth-options.c,v 1.39 2006/07/22 20:48:22 stevesk Exp $ */
/*
 * 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"

#include <sys/types.h>

#include <netdb.h>
#include <pwd.h>
#include <string.h>

#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
00146caa	1	/* $OpenBSD: auth-options.c,v 1.39 2006/07/22 20:48:22 stevesk Exp $ */
bcbf86ec	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
bcbf86ec	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
38c295d6	13	#include "includes.h"
38c295d6	14
b1842393	15	#include <sys/types.h>
b1842393	16
28cb0a43	17	#include <netdb.h>
b1842393	18	#include <pwd.h>
00146caa	19	#include <string.h>
b1842393	20
38c295d6	21	#include "xmalloc.h"
38c295d6	22	#include "match.h"
42f11eb2	23	#include "log.h"
42f11eb2	24	#include "canohost.h"
a5efa1bb	25	#include "channels.h"
42f11eb2	26	#include "auth-options.h"
61e96248	27	#include "servconf.h"
ed787d14	28	#include "misc.h"
1853d1ef	29	#include "monitor_wrap.h"
01dafcb5	30	#include "auth.h"
38c295d6	31
	32	/* Flags set authorized_keys flags */
	33	int no_port_forwarding_flag = 0;
	34	int no_agent_forwarding_flag = 0;
	35	int no_x11_forwarding_flag = 0;
	36	int no_pty_flag = 0;
	37
	38	/* "command=" option. */
	39	char *forced_command = NULL;
	40
	41	/* "environment=" options. */
	42	struct envstring *custom_environment = NULL;
	43
d20f3c9e	44	/* "tunnel=" option. */
	45	int forced_tun_device = -1;
	46
61e96248	47	extern ServerOptions options;
61e96248	48
94ec8c6b	49	void
	50	auth_clear_options(void)
	51	{
	52	no_agent_forwarding_flag = 0;
	53	no_port_forwarding_flag = 0;
	54	no_pty_flag = 0;
	55	no_x11_forwarding_flag = 0;
	56	while (custom_environment) {
	57	struct envstring *ce = custom_environment;
	58	custom_environment = ce->next;
	59	xfree(ce->s);
	60	xfree(ce);
	61	}
	62	if (forced_command) {
	63	xfree(forced_command);
	64	forced_command = NULL;
	65	}
d20f3c9e	66	forced_tun_device = -1;
01794848	67	channel_clear_permitted_opens();
01dafcb5	68	auth_debug_reset();
94ec8c6b	69	}
94ec8c6b	70
42f11eb2	71	/*
	72	* return 1 if access is granted, 0 if not.
	73	* side effect: sets key option flags
	74	*/
38c295d6	75	int
61e96248	76	auth_parse_options(struct passwd pw, char opts, char *file, u_long linenum)
38c295d6	77	{
38c295d6	78	const char *cp;
01794848	79	int i;
94ec8c6b	80
	81	/* reset options */
	82	auth_clear_options();
	83
e0b2cf6b	84	if (!opts)
	85	return 1;
	86
61e96248	87	while (opts && opts != ' ' && *opts != '\t') {
38c295d6	88	cp = "no-port-forwarding";
61e96248	89	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	90	auth_debug_add("Port forwarding disabled.");
38c295d6	91	no_port_forwarding_flag = 1;
61e96248	92	opts += strlen(cp);
38c295d6	93	goto next_option;
	94	}
	95	cp = "no-agent-forwarding";
61e96248	96	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	97	auth_debug_add("Agent forwarding disabled.");
38c295d6	98	no_agent_forwarding_flag = 1;
61e96248	99	opts += strlen(cp);
38c295d6	100	goto next_option;
	101	}
	102	cp = "no-X11-forwarding";
61e96248	103	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	104	auth_debug_add("X11 forwarding disabled.");
38c295d6	105	no_x11_forwarding_flag = 1;
61e96248	106	opts += strlen(cp);
38c295d6	107	goto next_option;
	108	}
	109	cp = "no-pty";
61e96248	110	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	111	auth_debug_add("Pty allocation disabled.");
38c295d6	112	no_pty_flag = 1;
61e96248	113	opts += strlen(cp);
38c295d6	114	goto next_option;
	115	}
	116	cp = "command=\"";
61e96248	117	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	118	opts += strlen(cp);
61e96248	119	forced_command = xmalloc(strlen(opts) + 1);
38c295d6	120	i = 0;
61e96248	121	while (*opts) {
61e96248	122	if (*opts == '"')
38c295d6	123	break;
61e96248	124	if (*opts == '\\' && opts[1] == '"') {
61e96248	125	opts += 2;
38c295d6	126	forced_command[i++] = '"';
	127	continue;
	128	}
61e96248	129	forced_command[i++] = *opts++;
38c295d6	130	}
61e96248	131	if (!*opts) {
38c295d6	132	debug("%.100s, line %lu: missing end quote",
42f11eb2	133	file, linenum);
01dafcb5	134	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	135	file, linenum);
acc9d6d7	136	xfree(forced_command);
	137	forced_command = NULL;
	138	goto bad_option;
38c295d6	139	}
774de098	140	forced_command[i] = '\0';
01dafcb5	141	auth_debug_add("Forced command: %.900s", forced_command);
61e96248	142	opts++;
38c295d6	143	goto next_option;
	144	}
	145	cp = "environment=\"";
f00bab84	146	if (options.permit_user_env &&
f00bab84	147	strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	148	char *s;
38c295d6	149	struct envstring *new_envstring;
01794848	150
61e96248	151	opts += strlen(cp);
61e96248	152	s = xmalloc(strlen(opts) + 1);
38c295d6	153	i = 0;
61e96248	154	while (*opts) {
61e96248	155	if (*opts == '"')
38c295d6	156	break;
61e96248	157	if (*opts == '\\' && opts[1] == '"') {
61e96248	158	opts += 2;
38c295d6	159	s[i++] = '"';
	160	continue;
	161	}
61e96248	162	s[i++] = *opts++;
38c295d6	163	}
61e96248	164	if (!*opts) {
38c295d6	165	debug("%.100s, line %lu: missing end quote",
42f11eb2	166	file, linenum);
01dafcb5	167	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	168	file, linenum);
acc9d6d7	169	xfree(s);
acc9d6d7	170	goto bad_option;
38c295d6	171	}
774de098	172	s[i] = '\0';
01dafcb5	173	auth_debug_add("Adding to environment: %.900s", s);
38c295d6	174	debug("Adding to environment: %.900s", s);
61e96248	175	opts++;
38c295d6	176	new_envstring = xmalloc(sizeof(struct envstring));
	177	new_envstring->s = s;
	178	new_envstring->next = custom_environment;
	179	custom_environment = new_envstring;
	180	goto next_option;
	181	}
	182	cp = "from=\"";
61e96248	183	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	184	const char *remote_ip = get_remote_ipaddr();
61e96248	185	const char *remote_host = get_canonical_hostname(
c5a7d788	186	options.use_dns);
61e96248	187	char *patterns = xmalloc(strlen(opts) + 1);
01794848	188
61e96248	189	opts += strlen(cp);
38c295d6	190	i = 0;
61e96248	191	while (*opts) {
61e96248	192	if (*opts == '"')
38c295d6	193	break;
61e96248	194	if (*opts == '\\' && opts[1] == '"') {
61e96248	195	opts += 2;
38c295d6	196	patterns[i++] = '"';
	197	continue;
	198	}
61e96248	199	patterns[i++] = *opts++;
38c295d6	200	}
61e96248	201	if (!*opts) {
38c295d6	202	debug("%.100s, line %lu: missing end quote",
42f11eb2	203	file, linenum);
01dafcb5	204	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	205	file, linenum);
acc9d6d7	206	xfree(patterns);
acc9d6d7	207	goto bad_option;
38c295d6	208	}
774de098	209	patterns[i] = '\0';
61e96248	210	opts++;
2cee8a25	211	if (match_host_and_ip(remote_host, remote_ip,
	212	patterns) != 1) {
	213	xfree(patterns);
bbe88b6d	214	logit("Authentication tried for %.100s with "
61e96248	215	"correct key but not from a permitted "
	216	"host (host=%.200s, ip=%.200s).",
	217	pw->pw_name, remote_host, remote_ip);
01dafcb5	218	auth_debug_add("Your host '%.200s' is not "
61e96248	219	"permitted to use this key for login.",
61e96248	220	remote_host);
38c295d6	221	/* deny access */
	222	return 0;
	223	}
2cee8a25	224	xfree(patterns);
38c295d6	225	/* Host name matches. */
	226	goto next_option;
	227	}
01794848	228	cp = "permitopen=\"";
01794848	229	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
3867aa0a	230	char host, p;
01794848	231	u_short port;
01794848	232	char *patterns = xmalloc(strlen(opts) + 1);
	233
	234	opts += strlen(cp);
	235	i = 0;
	236	while (*opts) {
	237	if (*opts == '"')
	238	break;
	239	if (*opts == '\\' && opts[1] == '"') {
	240	opts += 2;
	241	patterns[i++] = '"';
	242	continue;
	243	}
	244	patterns[i++] = *opts++;
	245	}
	246	if (!*opts) {
	247	debug("%.100s, line %lu: missing end quote",
	248	file, linenum);
3867aa0a	249	auth_debug_add("%.100s, line %lu: missing "
3867aa0a	250	"end quote", file, linenum);
01794848	251	xfree(patterns);
	252	goto bad_option;
	253	}
774de098	254	patterns[i] = '\0';
01794848	255	opts++;
3867aa0a	256	p = patterns;
	257	host = hpdelim(&p);
	258	if (host == NULL \|\| strlen(host) >= NI_MAXHOST) {
	259	debug("%.100s, line %lu: Bad permitopen "
16d3d2bc	260	"specification <%.100s>", file, linenum,
3867aa0a	261	patterns);
01dafcb5	262	auth_debug_add("%.100s, line %lu: "
3867aa0a	263	"Bad permitopen specification", file,
3867aa0a	264	linenum);
01794848	265	xfree(patterns);
	266	goto bad_option;
	267	}
f8cc7664	268	host = cleanhostname(host);
f8cc7664	269	if (p == NULL \|\| (port = a2port(p)) == 0) {
3867aa0a	270	debug("%.100s, line %lu: Bad permitopen port "
3867aa0a	271	"<%.100s>", file, linenum, p ? p : "");
01dafcb5	272	auth_debug_add("%.100s, line %lu: "
ed787d14	273	"Bad permitopen port", file, linenum);
01794848	274	xfree(patterns);
	275	goto bad_option;
	276	}
b1ed8313	277	if (options.allow_tcp_forwarding)
ed787d14	278	channel_add_permitted_opens(host, port);
01794848	279	xfree(patterns);
	280	goto next_option;
	281	}
d20f3c9e	282	cp = "tunnel=\"";
	283	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
	284	char *tun = NULL;
	285	opts += strlen(cp);
	286	tun = xmalloc(strlen(opts) + 1);
	287	i = 0;
	288	while (*opts) {
	289	if (*opts == '"')
	290	break;
	291	tun[i++] = *opts++;
	292	}
	293	if (!*opts) {
	294	debug("%.100s, line %lu: missing end quote",
	295	file, linenum);
	296	auth_debug_add("%.100s, line %lu: missing end quote",
	297	file, linenum);
	298	xfree(tun);
	299	forced_tun_device = -1;
	300	goto bad_option;
	301	}
774de098	302	tun[i] = '\0';
d20f3c9e	303	forced_tun_device = a2tun(tun, NULL);
d20f3c9e	304	xfree(tun);
a4f24bf8	305	if (forced_tun_device == SSH_TUNID_ERR) {
d20f3c9e	306	debug("%.100s, line %lu: invalid tun device",
	307	file, linenum);
	308	auth_debug_add("%.100s, line %lu: invalid tun device",
	309	file, linenum);
	310	forced_tun_device = -1;
	311	goto bad_option;
	312	}
	313	auth_debug_add("Forced tun device: %d", forced_tun_device);
	314	opts++;
	315	goto next_option;
	316	}
38c295d6	317	next_option:
	318	/*
	319	* Skip the comma, and move to the next option
	320	* (or break out if there are no more).
	321	*/
61e96248	322	if (!*opts)
38c295d6	323	fatal("Bugs in auth-options.c option processing.");
61e96248	324	if (opts == ' ' \|\| opts == '\t')
38c295d6	325	break; /* End of options. */
61e96248	326	if (*opts != ',')
38c295d6	327	goto bad_option;
61e96248	328	opts++;
38c295d6	329	/* Process the next option. */
38c295d6	330	}
1853d1ef	331
1853d1ef	332	if (!use_privsep)
01dafcb5	333	auth_debug_send();
1853d1ef	334
38c295d6	335	/* grant access */
	336	return 1;
	337
	338	bad_option:
bbe88b6d	339	logit("Bad options in %.100s file, line %lu: %.50s",
61e96248	340	file, linenum, opts);
01dafcb5	341	auth_debug_add("Bad options in %.100s file, line %lu: %.50s",
61e96248	342	file, linenum, opts);
1853d1ef	343
1853d1ef	344	if (!use_privsep)
01dafcb5	345	auth_debug_send();
1853d1ef	346
38c295d6	347	/* deny access */
	348	return 0;
	349	}