[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 1.21 2002/01/29 14:32:03 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 "misc.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();
}

/*
 * 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) {
			packet_send_debug("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) {
			packet_send_debug("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) {
			packet_send_debug("X11 forwarding disabled.");
			no_x11_forwarding_flag = 1;
			opts += strlen(cp);
			goto next_option;
		}
		cp = "no-pty";
		if (strncasecmp(opts, cp, strlen(cp)) == 0) {
			packet_send_debug("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);
				packet_send_debug("%.100s, line %lu: missing end quote",
				    file, linenum);
				xfree(forced_command);
				forced_command = NULL;
				goto bad_option;
			}
			forced_command[i] = 0;
			packet_send_debug("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);
				packet_send_debug("%.100s, line %lu: missing end quote",
				    file, linenum);
				xfree(s);
				goto bad_option;
			}
			s[i] = 0;
			packet_send_debug("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);
				packet_send_debug("%.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);
				packet_send_debug("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);
				packet_send_debug("%.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);
				packet_send_debug("%.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);
				packet_send_debug("%.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. */
	}
	/* grant access */
	return 1;

bad_option:
	log("Bad options in %.100s file, line %lu: %.50s",
	    file, linenum, opts);
	packet_send_debug("Bad options in %.100s file, line %lu: %.50s",
	    file, linenum, opts);
	/* 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"
bf4c5edc	13	RCSID("$OpenBSD: auth-options.c,v 1.21 2002/01/29 14:32:03 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"
ed787d14	23	#include "misc.h"
38c295d6	24
	25	/* Flags set authorized_keys flags */
	26	int no_port_forwarding_flag = 0;
	27	int no_agent_forwarding_flag = 0;
	28	int no_x11_forwarding_flag = 0;
	29	int no_pty_flag = 0;
	30
	31	/* "command=" option. */
	32	char *forced_command = NULL;
	33
	34	/* "environment=" options. */
	35	struct envstring *custom_environment = NULL;
	36
61e96248	37	extern ServerOptions options;
61e96248	38
94ec8c6b	39	void
	40	auth_clear_options(void)
	41	{
	42	no_agent_forwarding_flag = 0;
	43	no_port_forwarding_flag = 0;
	44	no_pty_flag = 0;
	45	no_x11_forwarding_flag = 0;
	46	while (custom_environment) {
	47	struct envstring *ce = custom_environment;
	48	custom_environment = ce->next;
	49	xfree(ce->s);
	50	xfree(ce);
	51	}
	52	if (forced_command) {
	53	xfree(forced_command);
	54	forced_command = NULL;
	55	}
01794848	56	channel_clear_permitted_opens();
94ec8c6b	57	}
94ec8c6b	58
42f11eb2	59	/*
	60	* return 1 if access is granted, 0 if not.
	61	* side effect: sets key option flags
	62	*/
38c295d6	63	int
61e96248	64	auth_parse_options(struct passwd pw, char opts, char *file, u_long linenum)
38c295d6	65	{
38c295d6	66	const char *cp;
01794848	67	int i;
94ec8c6b	68
	69	/* reset options */
	70	auth_clear_options();
	71
e0b2cf6b	72	if (!opts)
	73	return 1;
	74
61e96248	75	while (opts && opts != ' ' && *opts != '\t') {
38c295d6	76	cp = "no-port-forwarding";
61e96248	77	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	78	packet_send_debug("Port forwarding disabled.");
38c295d6	79	no_port_forwarding_flag = 1;
61e96248	80	opts += strlen(cp);
38c295d6	81	goto next_option;
	82	}
	83	cp = "no-agent-forwarding";
61e96248	84	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	85	packet_send_debug("Agent forwarding disabled.");
38c295d6	86	no_agent_forwarding_flag = 1;
61e96248	87	opts += strlen(cp);
38c295d6	88	goto next_option;
	89	}
	90	cp = "no-X11-forwarding";
61e96248	91	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	92	packet_send_debug("X11 forwarding disabled.");
38c295d6	93	no_x11_forwarding_flag = 1;
61e96248	94	opts += strlen(cp);
38c295d6	95	goto next_option;
	96	}
	97	cp = "no-pty";
61e96248	98	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	99	packet_send_debug("Pty allocation disabled.");
38c295d6	100	no_pty_flag = 1;
61e96248	101	opts += strlen(cp);
38c295d6	102	goto next_option;
	103	}
	104	cp = "command=\"";
61e96248	105	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	106	opts += strlen(cp);
61e96248	107	forced_command = xmalloc(strlen(opts) + 1);
38c295d6	108	i = 0;
61e96248	109	while (*opts) {
61e96248	110	if (*opts == '"')
38c295d6	111	break;
61e96248	112	if (*opts == '\\' && opts[1] == '"') {
61e96248	113	opts += 2;
38c295d6	114	forced_command[i++] = '"';
	115	continue;
	116	}
61e96248	117	forced_command[i++] = *opts++;
38c295d6	118	}
61e96248	119	if (!*opts) {
38c295d6	120	debug("%.100s, line %lu: missing end quote",
42f11eb2	121	file, linenum);
38c295d6	122	packet_send_debug("%.100s, line %lu: missing end quote",
42f11eb2	123	file, linenum);
acc9d6d7	124	xfree(forced_command);
	125	forced_command = NULL;
	126	goto bad_option;
38c295d6	127	}
	128	forced_command[i] = 0;
	129	packet_send_debug("Forced command: %.900s", forced_command);
61e96248	130	opts++;
38c295d6	131	goto next_option;
	132	}
	133	cp = "environment=\"";
61e96248	134	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	135	char *s;
38c295d6	136	struct envstring *new_envstring;
01794848	137
61e96248	138	opts += strlen(cp);
61e96248	139	s = xmalloc(strlen(opts) + 1);
38c295d6	140	i = 0;
61e96248	141	while (*opts) {
61e96248	142	if (*opts == '"')
38c295d6	143	break;
61e96248	144	if (*opts == '\\' && opts[1] == '"') {
61e96248	145	opts += 2;
38c295d6	146	s[i++] = '"';
	147	continue;
	148	}
61e96248	149	s[i++] = *opts++;
38c295d6	150	}
61e96248	151	if (!*opts) {
38c295d6	152	debug("%.100s, line %lu: missing end quote",
42f11eb2	153	file, linenum);
38c295d6	154	packet_send_debug("%.100s, line %lu: missing end quote",
42f11eb2	155	file, linenum);
acc9d6d7	156	xfree(s);
acc9d6d7	157	goto bad_option;
38c295d6	158	}
	159	s[i] = 0;
	160	packet_send_debug("Adding to environment: %.900s", s);
	161	debug("Adding to environment: %.900s", s);
61e96248	162	opts++;
38c295d6	163	new_envstring = xmalloc(sizeof(struct envstring));
	164	new_envstring->s = s;
	165	new_envstring->next = custom_environment;
	166	custom_environment = new_envstring;
	167	goto next_option;
	168	}
	169	cp = "from=\"";
61e96248	170	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
61e96248	171	const char *remote_ip = get_remote_ipaddr();
61e96248	172	const char *remote_host = get_canonical_hostname(
bf4c5edc	173	options.verify_reverse_mapping);
61e96248	174	char *patterns = xmalloc(strlen(opts) + 1);
01794848	175
61e96248	176	opts += strlen(cp);
38c295d6	177	i = 0;
61e96248	178	while (*opts) {
61e96248	179	if (*opts == '"')
38c295d6	180	break;
61e96248	181	if (*opts == '\\' && opts[1] == '"') {
61e96248	182	opts += 2;
38c295d6	183	patterns[i++] = '"';
	184	continue;
	185	}
61e96248	186	patterns[i++] = *opts++;
38c295d6	187	}
61e96248	188	if (!*opts) {
38c295d6	189	debug("%.100s, line %lu: missing end quote",
42f11eb2	190	file, linenum);
38c295d6	191	packet_send_debug("%.100s, line %lu: missing end quote",
42f11eb2	192	file, linenum);
acc9d6d7	193	xfree(patterns);
acc9d6d7	194	goto bad_option;
38c295d6	195	}
38c295d6	196	patterns[i] = 0;
61e96248	197	opts++;
2cee8a25	198	if (match_host_and_ip(remote_host, remote_ip,
	199	patterns) != 1) {
	200	xfree(patterns);
61e96248	201	log("Authentication tried for %.100s with "
	202	"correct key but not from a permitted "
	203	"host (host=%.200s, ip=%.200s).",
	204	pw->pw_name, remote_host, remote_ip);
	205	packet_send_debug("Your host '%.200s' is not "
	206	"permitted to use this key for login.",
	207	remote_host);
38c295d6	208	/* deny access */
	209	return 0;
	210	}
2cee8a25	211	xfree(patterns);
38c295d6	212	/* Host name matches. */
	213	goto next_option;
	214	}
01794848	215	cp = "permitopen=\"";
01794848	216	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
ed787d14	217	char host[256], sport[6];
01794848	218	u_short port;
01794848	219	char *patterns = xmalloc(strlen(opts) + 1);
	220
	221	opts += strlen(cp);
	222	i = 0;
	223	while (*opts) {
	224	if (*opts == '"')
	225	break;
	226	if (*opts == '\\' && opts[1] == '"') {
	227	opts += 2;
	228	patterns[i++] = '"';
	229	continue;
	230	}
	231	patterns[i++] = *opts++;
	232	}
	233	if (!*opts) {
	234	debug("%.100s, line %lu: missing end quote",
	235	file, linenum);
	236	packet_send_debug("%.100s, line %lu: missing end quote",
	237	file, linenum);
	238	xfree(patterns);
	239	goto bad_option;
	240	}
	241	patterns[i] = 0;
	242	opts++;
ed787d14	243	if (sscanf(patterns, "%255[^:]:%5[0-9]", host, sport) != 2 &&
	244	sscanf(patterns, "%255[^/]/%5[0-9]", host, sport) != 2) {
	245	debug("%.100s, line %lu: Bad permitopen specification "
	246	"<%.100s>", file, linenum, patterns);
	247	packet_send_debug("%.100s, line %lu: "
	248	"Bad permitopen specification", file, linenum);
01794848	249	xfree(patterns);
	250	goto bad_option;
	251	}
ed787d14	252	if ((port = a2port(sport)) == 0) {
	253	debug("%.100s, line %lu: Bad permitopen port <%.100s>",
	254	file, linenum, sport);
	255	packet_send_debug("%.100s, line %lu: "
	256	"Bad permitopen port", file, linenum);
01794848	257	xfree(patterns);
	258	goto bad_option;
	259	}
b1ed8313	260	if (options.allow_tcp_forwarding)
ed787d14	261	channel_add_permitted_opens(host, port);
01794848	262	xfree(patterns);
	263	goto next_option;
	264	}
38c295d6	265	next_option:
	266	/*
	267	* Skip the comma, and move to the next option
	268	* (or break out if there are no more).
	269	*/
61e96248	270	if (!*opts)
38c295d6	271	fatal("Bugs in auth-options.c option processing.");
61e96248	272	if (opts == ' ' \|\| opts == '\t')
38c295d6	273	break; /* End of options. */
61e96248	274	if (*opts != ',')
38c295d6	275	goto bad_option;
61e96248	276	opts++;
38c295d6	277	/* Process the next option. */
	278	}
	279	/* grant access */
	280	return 1;
	281
	282	bad_option:
	283	log("Bad options in %.100s file, line %lu: %.50s",
61e96248	284	file, linenum, opts);
38c295d6	285	packet_send_debug("Bad options in %.100s file, line %lu: %.50s",
61e96248	286	file, linenum, opts);
38c295d6	287	/* deny access */
	288	return 0;
	289	}