[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 1.24 2002/05/13 20:44:58 markus Exp $");

#include "packet.h"
#include "xmalloc.h"
#include "match.h"
#include "log.h"
#include "canohost.h"
#include "channels.h"
#include "auth-options.h"
#include "servconf.h"
#include "bufaux.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 (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.verify_reverse_mapping);
			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);
				log("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:
	log("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"
01dafcb5	13	RCSID("$OpenBSD: auth-options.c,v 1.24 2002/05/13 20:44:58 markus Exp $");
38c295d6	14
38c295d6	15	#include "packet.h"
	16	#include "xmalloc.h"
	17	#include "match.h"
42f11eb2	18	#include "log.h"
42f11eb2	19	#include "canohost.h"
a5efa1bb	20	#include "channels.h"
42f11eb2	21	#include "auth-options.h"
61e96248	22	#include "servconf.h"
1853d1ef	23	#include "bufaux.h"
ed787d14	24	#include "misc.h"
1853d1ef	25	#include "monitor_wrap.h"
01dafcb5	26	#include "auth.h"
38c295d6	27
	28	/* Flags set authorized_keys flags */
	29	int no_port_forwarding_flag = 0;
	30	int no_agent_forwarding_flag = 0;
	31	int no_x11_forwarding_flag = 0;
	32	int no_pty_flag = 0;
	33
	34	/* "command=" option. */
	35	char *forced_command = NULL;
	36
	37	/* "environment=" options. */
	38	struct envstring *custom_environment = NULL;
	39
61e96248	40	extern ServerOptions options;
61e96248	41
94ec8c6b	42	void
	43	auth_clear_options(void)
	44	{
	45	no_agent_forwarding_flag = 0;
	46	no_port_forwarding_flag = 0;
	47	no_pty_flag = 0;
	48	no_x11_forwarding_flag = 0;
	49	while (custom_environment) {
	50	struct envstring *ce = custom_environment;
	51	custom_environment = ce->next;
	52	xfree(ce->s);
	53	xfree(ce);
	54	}
	55	if (forced_command) {
	56	xfree(forced_command);
	57	forced_command = NULL;
	58	}
01794848	59	channel_clear_permitted_opens();
01dafcb5	60	auth_debug_reset();
94ec8c6b	61	}
94ec8c6b	62
42f11eb2	63	/*
	64	* return 1 if access is granted, 0 if not.
	65	* side effect: sets key option flags
	66	*/
38c295d6	67	int
61e96248	68	auth_parse_options(struct passwd pw, char opts, char *file, u_long linenum)
38c295d6	69	{
38c295d6	70	const char *cp;
01794848	71	int i;
94ec8c6b	72
	73	/* reset options */
	74	auth_clear_options();
	75
e0b2cf6b	76	if (!opts)
	77	return 1;
	78
61e96248	79	while (opts && opts != ' ' && *opts != '\t') {
38c295d6	80	cp = "no-port-forwarding";
61e96248	81	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	82	auth_debug_add("Port forwarding disabled.");
38c295d6	83	no_port_forwarding_flag = 1;
61e96248	84	opts += strlen(cp);
38c295d6	85	goto next_option;
	86	}
	87	cp = "no-agent-forwarding";
61e96248	88	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	89	auth_debug_add("Agent forwarding disabled.");
38c295d6	90	no_agent_forwarding_flag = 1;
61e96248	91	opts += strlen(cp);
38c295d6	92	goto next_option;
	93	}
	94	cp = "no-X11-forwarding";
61e96248	95	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	96	auth_debug_add("X11 forwarding disabled.");
38c295d6	97	no_x11_forwarding_flag = 1;
61e96248	98	opts += strlen(cp);
38c295d6	99	goto next_option;
	100	}
	101	cp = "no-pty";
61e96248	102	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
01dafcb5	103	auth_debug_add("Pty allocation disabled.");
38c295d6	104	no_pty_flag = 1;
61e96248	105	opts += strlen(cp);
38c295d6	106	goto next_option;
	107	}
	108	cp = "command=\"";
61e96248	109	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	110	opts += strlen(cp);
61e96248	111	forced_command = xmalloc(strlen(opts) + 1);
38c295d6	112	i = 0;
61e96248	113	while (*opts) {
61e96248	114	if (*opts == '"')
38c295d6	115	break;
61e96248	116	if (*opts == '\\' && opts[1] == '"') {
61e96248	117	opts += 2;
38c295d6	118	forced_command[i++] = '"';
	119	continue;
	120	}
61e96248	121	forced_command[i++] = *opts++;
38c295d6	122	}
61e96248	123	if (!*opts) {
38c295d6	124	debug("%.100s, line %lu: missing end quote",
42f11eb2	125	file, linenum);
01dafcb5	126	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	127	file, linenum);
acc9d6d7	128	xfree(forced_command);
	129	forced_command = NULL;
	130	goto bad_option;
38c295d6	131	}
38c295d6	132	forced_command[i] = 0;
01dafcb5	133	auth_debug_add("Forced command: %.900s", forced_command);
61e96248	134	opts++;
38c295d6	135	goto next_option;
	136	}
	137	cp = "environment=\"";
61e96248	138	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	139	char *s;
38c295d6	140	struct envstring *new_envstring;
01794848	141
61e96248	142	opts += strlen(cp);
61e96248	143	s = xmalloc(strlen(opts) + 1);
38c295d6	144	i = 0;
61e96248	145	while (*opts) {
61e96248	146	if (*opts == '"')
38c295d6	147	break;
61e96248	148	if (*opts == '\\' && opts[1] == '"') {
61e96248	149	opts += 2;
38c295d6	150	s[i++] = '"';
	151	continue;
	152	}
61e96248	153	s[i++] = *opts++;
38c295d6	154	}
61e96248	155	if (!*opts) {
38c295d6	156	debug("%.100s, line %lu: missing end quote",
42f11eb2	157	file, linenum);
01dafcb5	158	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	159	file, linenum);
acc9d6d7	160	xfree(s);
acc9d6d7	161	goto bad_option;
38c295d6	162	}
38c295d6	163	s[i] = 0;
01dafcb5	164	auth_debug_add("Adding to environment: %.900s", s);
38c295d6	165	debug("Adding to environment: %.900s", s);
61e96248	166	opts++;
38c295d6	167	new_envstring = xmalloc(sizeof(struct envstring));
	168	new_envstring->s = s;
	169	new_envstring->next = custom_environment;
	170	custom_environment = new_envstring;
	171	goto next_option;
	172	}
	173	cp = "from=\"";
61e96248	174	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	175	const char *remote_ip = get_remote_ipaddr();
61e96248	176	const char *remote_host = get_canonical_hostname(
bf4c5edc	177	options.verify_reverse_mapping);
61e96248	178	char *patterns = xmalloc(strlen(opts) + 1);
01794848	179
61e96248	180	opts += strlen(cp);
38c295d6	181	i = 0;
61e96248	182	while (*opts) {
61e96248	183	if (*opts == '"')
38c295d6	184	break;
61e96248	185	if (*opts == '\\' && opts[1] == '"') {
61e96248	186	opts += 2;
38c295d6	187	patterns[i++] = '"';
	188	continue;
	189	}
61e96248	190	patterns[i++] = *opts++;
38c295d6	191	}
61e96248	192	if (!*opts) {
38c295d6	193	debug("%.100s, line %lu: missing end quote",
42f11eb2	194	file, linenum);
01dafcb5	195	auth_debug_add("%.100s, line %lu: missing end quote",
42f11eb2	196	file, linenum);
acc9d6d7	197	xfree(patterns);
acc9d6d7	198	goto bad_option;
38c295d6	199	}
38c295d6	200	patterns[i] = 0;
61e96248	201	opts++;
2cee8a25	202	if (match_host_and_ip(remote_host, remote_ip,
	203	patterns) != 1) {
	204	xfree(patterns);
61e96248	205	log("Authentication tried for %.100s with "
	206	"correct key but not from a permitted "
	207	"host (host=%.200s, ip=%.200s).",
	208	pw->pw_name, remote_host, remote_ip);
01dafcb5	209	auth_debug_add("Your host '%.200s' is not "
61e96248	210	"permitted to use this key for login.",
61e96248	211	remote_host);
38c295d6	212	/* deny access */
	213	return 0;
	214	}
2cee8a25	215	xfree(patterns);
38c295d6	216	/* Host name matches. */
	217	goto next_option;
	218	}
01794848	219	cp = "permitopen=\"";
01794848	220	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
ed787d14	221	char host[256], sport[6];
01794848	222	u_short port;
01794848	223	char *patterns = xmalloc(strlen(opts) + 1);
	224
	225	opts += strlen(cp);
	226	i = 0;
	227	while (*opts) {
	228	if (*opts == '"')
	229	break;
	230	if (*opts == '\\' && opts[1] == '"') {
	231	opts += 2;
	232	patterns[i++] = '"';
	233	continue;
	234	}
	235	patterns[i++] = *opts++;
	236	}
	237	if (!*opts) {
	238	debug("%.100s, line %lu: missing end quote",
	239	file, linenum);
01dafcb5	240	auth_debug_add("%.100s, line %lu: missing end quote",
01794848	241	file, linenum);
	242	xfree(patterns);
	243	goto bad_option;
	244	}
	245	patterns[i] = 0;
	246	opts++;
ed787d14	247	if (sscanf(patterns, "%255[^:]:%5[0-9]", host, sport) != 2 &&
	248	sscanf(patterns, "%255[^/]/%5[0-9]", host, sport) != 2) {
	249	debug("%.100s, line %lu: Bad permitopen specification "
	250	"<%.100s>", file, linenum, patterns);
01dafcb5	251	auth_debug_add("%.100s, line %lu: "
ed787d14	252	"Bad permitopen specification", file, linenum);
01794848	253	xfree(patterns);
	254	goto bad_option;
	255	}
ed787d14	256	if ((port = a2port(sport)) == 0) {
	257	debug("%.100s, line %lu: Bad permitopen port <%.100s>",
	258	file, linenum, sport);
01dafcb5	259	auth_debug_add("%.100s, line %lu: "
ed787d14	260	"Bad permitopen port", file, linenum);
01794848	261	xfree(patterns);
	262	goto bad_option;
	263	}
b1ed8313	264	if (options.allow_tcp_forwarding)
ed787d14	265	channel_add_permitted_opens(host, port);
01794848	266	xfree(patterns);
	267	goto next_option;
	268	}
38c295d6	269	next_option:
	270	/*
	271	* Skip the comma, and move to the next option
	272	* (or break out if there are no more).
	273	*/
61e96248	274	if (!*opts)
38c295d6	275	fatal("Bugs in auth-options.c option processing.");
61e96248	276	if (opts == ' ' \|\| opts == '\t')
38c295d6	277	break; /* End of options. */
61e96248	278	if (*opts != ',')
38c295d6	279	goto bad_option;
61e96248	280	opts++;
38c295d6	281	/* Process the next option. */
38c295d6	282	}
1853d1ef	283
1853d1ef	284	if (!use_privsep)
01dafcb5	285	auth_debug_send();
1853d1ef	286
38c295d6	287	/* grant access */
	288	return 1;
	289
	290	bad_option:
	291	log("Bad options in %.100s file, line %lu: %.50s",
61e96248	292	file, linenum, opts);
01dafcb5	293	auth_debug_add("Bad options in %.100s file, line %lu: %.50s",
61e96248	294	file, linenum, opts);
1853d1ef	295
1853d1ef	296	if (!use_privsep)
01dafcb5	297	auth_debug_send();
1853d1ef	298
38c295d6	299	/* deny access */
	300	return 0;
	301	}