[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 1.12 2001/02/03 10:08:36 markus Exp $");

#include "packet.h"
#include "xmalloc.h"
#include "match.h"
#include "log.h"
#include "canohost.h"
#include "auth-options.h"
#include "servconf.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;
	}
}

/*
 * 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;
	if (!opts)
		return 1;

	/* reset options */
	auth_clear_options();

	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) {
			int i;
			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);
				continue;
			}
			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) {
			int i;
			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);
				continue;
			}
			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) {
			int mname, mip;
			const char *remote_ip = get_remote_ipaddr();
			const char *remote_host = get_canonical_hostname(
			    options.reverse_mapping_check);
			char *patterns = xmalloc(strlen(opts) + 1);
			int i;
			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);
				continue;
			}
			patterns[i] = 0;
			opts++;
			/*
			 * Deny access if we get a negative
			 * match for the hostname or the ip
			 * or if we get not match at all
			 */
			mname = match_hostname(remote_host, patterns,
			    strlen(patterns));
			mip = match_hostname(remote_ip, patterns,
			    strlen(patterns));
			xfree(patterns);
			if (mname == -1 || mip == -1 ||
			    (mname != 1 && mip != 1)) {
				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;
			}
			/* Host name matches. */
			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"
61e96248	13	RCSID("$OpenBSD: auth-options.c,v 1.12 2001/02/03 10:08:36 markus Exp $");
38c295d6	14
38c295d6	15	#include "packet.h"
	16	#include "xmalloc.h"
	17	#include "match.h"
42f11eb2	18	#include "log.h"
	19	#include "canohost.h"
	20	#include "auth-options.h"
61e96248	21	#include "servconf.h"
38c295d6	22
	23	/* Flags set authorized_keys flags */
	24	int no_port_forwarding_flag = 0;
	25	int no_agent_forwarding_flag = 0;
	26	int no_x11_forwarding_flag = 0;
	27	int no_pty_flag = 0;
	28
	29	/* "command=" option. */
	30	char *forced_command = NULL;
	31
	32	/* "environment=" options. */
	33	struct envstring *custom_environment = NULL;
	34
61e96248	35	extern ServerOptions options;
61e96248	36
94ec8c6b	37	void
	38	auth_clear_options(void)
	39	{
	40	no_agent_forwarding_flag = 0;
	41	no_port_forwarding_flag = 0;
	42	no_pty_flag = 0;
	43	no_x11_forwarding_flag = 0;
	44	while (custom_environment) {
	45	struct envstring *ce = custom_environment;
	46	custom_environment = ce->next;
	47	xfree(ce->s);
	48	xfree(ce);
	49	}
	50	if (forced_command) {
	51	xfree(forced_command);
	52	forced_command = NULL;
	53	}
	54	}
	55
42f11eb2	56	/*
	57	* return 1 if access is granted, 0 if not.
	58	* side effect: sets key option flags
	59	*/
38c295d6	60	int
61e96248	61	auth_parse_options(struct passwd pw, char opts, char *file, u_long linenum)
38c295d6	62	{
38c295d6	63	const char *cp;
61e96248	64	if (!opts)
38c295d6	65	return 1;
94ec8c6b	66
	67	/* reset options */
	68	auth_clear_options();
	69
61e96248	70	while (opts && opts != ' ' && *opts != '\t') {
38c295d6	71	cp = "no-port-forwarding";
61e96248	72	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	73	packet_send_debug("Port forwarding disabled.");
38c295d6	74	no_port_forwarding_flag = 1;
61e96248	75	opts += strlen(cp);
38c295d6	76	goto next_option;
	77	}
	78	cp = "no-agent-forwarding";
61e96248	79	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	80	packet_send_debug("Agent forwarding disabled.");
38c295d6	81	no_agent_forwarding_flag = 1;
61e96248	82	opts += strlen(cp);
38c295d6	83	goto next_option;
	84	}
	85	cp = "no-X11-forwarding";
61e96248	86	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	87	packet_send_debug("X11 forwarding disabled.");
38c295d6	88	no_x11_forwarding_flag = 1;
61e96248	89	opts += strlen(cp);
38c295d6	90	goto next_option;
	91	}
	92	cp = "no-pty";
61e96248	93	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	94	packet_send_debug("Pty allocation disabled.");
38c295d6	95	no_pty_flag = 1;
61e96248	96	opts += strlen(cp);
38c295d6	97	goto next_option;
	98	}
	99	cp = "command=\"";
61e96248	100	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	101	int i;
61e96248	102	opts += strlen(cp);
61e96248	103	forced_command = xmalloc(strlen(opts) + 1);
38c295d6	104	i = 0;
61e96248	105	while (*opts) {
61e96248	106	if (*opts == '"')
38c295d6	107	break;
61e96248	108	if (*opts == '\\' && opts[1] == '"') {
61e96248	109	opts += 2;
38c295d6	110	forced_command[i++] = '"';
	111	continue;
	112	}
61e96248	113	forced_command[i++] = *opts++;
38c295d6	114	}
61e96248	115	if (!*opts) {
38c295d6	116	debug("%.100s, line %lu: missing end quote",
42f11eb2	117	file, linenum);
38c295d6	118	packet_send_debug("%.100s, line %lu: missing end quote",
42f11eb2	119	file, linenum);
38c295d6	120	continue;
	121	}
	122	forced_command[i] = 0;
	123	packet_send_debug("Forced command: %.900s", forced_command);
61e96248	124	opts++;
38c295d6	125	goto next_option;
	126	}
	127	cp = "environment=\"";
61e96248	128	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	129	int i;
	130	char *s;
	131	struct envstring *new_envstring;
61e96248	132	opts += strlen(cp);
61e96248	133	s = xmalloc(strlen(opts) + 1);
38c295d6	134	i = 0;
61e96248	135	while (*opts) {
61e96248	136	if (*opts == '"')
38c295d6	137	break;
61e96248	138	if (*opts == '\\' && opts[1] == '"') {
61e96248	139	opts += 2;
38c295d6	140	s[i++] = '"';
	141	continue;
	142	}
61e96248	143	s[i++] = *opts++;
38c295d6	144	}
61e96248	145	if (!*opts) {
38c295d6	146	debug("%.100s, line %lu: missing end quote",
42f11eb2	147	file, linenum);
38c295d6	148	packet_send_debug("%.100s, line %lu: missing end quote",
42f11eb2	149	file, linenum);
38c295d6	150	continue;
	151	}
	152	s[i] = 0;
	153	packet_send_debug("Adding to environment: %.900s", s);
	154	debug("Adding to environment: %.900s", s);
61e96248	155	opts++;
38c295d6	156	new_envstring = xmalloc(sizeof(struct envstring));
	157	new_envstring->s = s;
	158	new_envstring->next = custom_environment;
	159	custom_environment = new_envstring;
	160	goto next_option;
	161	}
	162	cp = "from=\"";
61e96248	163	if (strncasecmp(opts, cp, strlen(cp)) == 0) {
38c295d6	164	int mname, mip;
61e96248	165	const char *remote_ip = get_remote_ipaddr();
	166	const char *remote_host = get_canonical_hostname(
	167	options.reverse_mapping_check);
	168	char *patterns = xmalloc(strlen(opts) + 1);
38c295d6	169	int i;
61e96248	170	opts += strlen(cp);
38c295d6	171	i = 0;
61e96248	172	while (*opts) {
61e96248	173	if (*opts == '"')
38c295d6	174	break;
61e96248	175	if (*opts == '\\' && opts[1] == '"') {
61e96248	176	opts += 2;
38c295d6	177	patterns[i++] = '"';
	178	continue;
	179	}
61e96248	180	patterns[i++] = *opts++;
38c295d6	181	}
61e96248	182	if (!*opts) {
38c295d6	183	debug("%.100s, line %lu: missing end quote",
42f11eb2	184	file, linenum);
38c295d6	185	packet_send_debug("%.100s, line %lu: missing end quote",
42f11eb2	186	file, linenum);
38c295d6	187	continue;
	188	}
	189	patterns[i] = 0;
61e96248	190	opts++;
38c295d6	191	/*
	192	* Deny access if we get a negative
	193	* match for the hostname or the ip
	194	* or if we get not match at all
	195	*/
61e96248	196	mname = match_hostname(remote_host, patterns,
	197	strlen(patterns));
	198	mip = match_hostname(remote_ip, patterns,
	199	strlen(patterns));
38c295d6	200	xfree(patterns);
	201	if (mname == -1 \|\| mip == -1 \|\|
	202	(mname != 1 && mip != 1)) {
61e96248	203	log("Authentication tried for %.100s with "
	204	"correct key but not from a permitted "
	205	"host (host=%.200s, ip=%.200s).",
	206	pw->pw_name, remote_host, remote_ip);
	207	packet_send_debug("Your host '%.200s' is not "
	208	"permitted to use this key for login.",
	209	remote_host);
38c295d6	210	/* deny access */
	211	return 0;
	212	}
	213	/* Host name matches. */
	214	goto next_option;
	215	}
	216	next_option:
	217	/*
	218	* Skip the comma, and move to the next option
	219	* (or break out if there are no more).
	220	*/
61e96248	221	if (!*opts)
38c295d6	222	fatal("Bugs in auth-options.c option processing.");
61e96248	223	if (opts == ' ' \|\| opts == '\t')
38c295d6	224	break; /* End of options. */
61e96248	225	if (*opts != ',')
38c295d6	226	goto bad_option;
61e96248	227	opts++;
38c295d6	228	/* Process the next option. */
	229	}
	230	/* grant access */
	231	return 1;
	232
	233	bad_option:
	234	log("Bad options in %.100s file, line %lu: %.50s",
61e96248	235	file, linenum, opts);
38c295d6	236	packet_send_debug("Bad options in %.100s file, line %lu: %.50s",
61e96248	237	file, linenum, opts);
38c295d6	238	/* deny access */
	239	return 0;
	240	}