[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 1.11 2001/01/21 19:05:41 markus Exp $");

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

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 *options, char *file, u_long linenum)
{
	const char *cp;
	if (!options)
		return 1;

	/* reset options */
	auth_clear_options();

	while (*options && *options != ' ' && *options != '\t') {
		cp = "no-port-forwarding";
		if (strncasecmp(options, cp, strlen(cp)) == 0) {
			packet_send_debug("Port forwarding disabled.");
			no_port_forwarding_flag = 1;
			options += strlen(cp);
			goto next_option;
		}
		cp = "no-agent-forwarding";
		if (strncasecmp(options, cp, strlen(cp)) == 0) {
			packet_send_debug("Agent forwarding disabled.");
			no_agent_forwarding_flag = 1;
			options += strlen(cp);
			goto next_option;
		}
		cp = "no-X11-forwarding";
		if (strncasecmp(options, cp, strlen(cp)) == 0) {
			packet_send_debug("X11 forwarding disabled.");
			no_x11_forwarding_flag = 1;
			options += strlen(cp);
			goto next_option;
		}
		cp = "no-pty";
		if (strncasecmp(options, cp, strlen(cp)) == 0) {
			packet_send_debug("Pty allocation disabled.");
			no_pty_flag = 1;
			options += strlen(cp);
			goto next_option;
		}
		cp = "command=\"";
		if (strncasecmp(options, cp, strlen(cp)) == 0) {
			int i;
			options += strlen(cp);
			forced_command = xmalloc(strlen(options) + 1);
			i = 0;
			while (*options) {
				if (*options == '"')
					break;
				if (*options == '\\' && options[1] == '"') {
					options += 2;
					forced_command[i++] = '"';
					continue;
				}
				forced_command[i++] = *options++;
			}
			if (!*options) {
				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);
			options++;
			goto next_option;
		}
		cp = "environment=\"";
		if (strncasecmp(options, cp, strlen(cp)) == 0) {
			int i;
			char *s;
			struct envstring *new_envstring;
			options += strlen(cp);
			s = xmalloc(strlen(options) + 1);
			i = 0;
			while (*options) {
				if (*options == '"')
					break;
				if (*options == '\\' && options[1] == '"') {
					options += 2;
					s[i++] = '"';
					continue;
				}
				s[i++] = *options++;
			}
			if (!*options) {
				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);
			options++;
			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(options, cp, strlen(cp)) == 0) {
			int mname, mip;
			char *patterns = xmalloc(strlen(options) + 1);
			int i;
			options += strlen(cp);
			i = 0;
			while (*options) {
				if (*options == '"')
					break;
				if (*options == '\\' && options[1] == '"') {
					options += 2;
					patterns[i++] = '"';
					continue;
				}
				patterns[i++] = *options++;
			}
			if (!*options) {
				debug("%.100s, line %lu: missing end quote",
				    file, linenum);
				packet_send_debug("%.100s, line %lu: missing end quote",
				    file, linenum);
				continue;
			}
			patterns[i] = 0;
			options++;
			/*
			 * 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(get_canonical_hostname(),
			    patterns, strlen(patterns));
			mip = match_hostname(get_remote_ipaddr(),
			    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, get_canonical_hostname(),
				    get_remote_ipaddr());
				packet_send_debug("Your host '%.200s' is not permitted to use this key for login.",
				get_canonical_hostname());
				/* 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 (!*options)
			fatal("Bugs in auth-options.c option processing.");
		if (*options == ' ' || *options == '\t')
			break;		/* End of options. */
		if (*options != ',')
			goto bad_option;
		options++;
		/* Process the next option. */
	}
	/* grant access */
	return 1;

bad_option:
	log("Bad options in %.100s file, line %lu: %.50s",
	    file, linenum, options);
	packet_send_debug("Bad options in %.100s file, line %lu: %.50s",
	    file, linenum, options);
	/* 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"
42f11eb2	13	RCSID("$OpenBSD: auth-options.c,v 1.11 2001/01/21 19:05:41 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"
38c295d6	21
	22	/* Flags set authorized_keys flags */
	23	int no_port_forwarding_flag = 0;
	24	int no_agent_forwarding_flag = 0;
	25	int no_x11_forwarding_flag = 0;
	26	int no_pty_flag = 0;
	27
	28	/* "command=" option. */
	29	char *forced_command = NULL;
	30
	31	/* "environment=" options. */
	32	struct envstring *custom_environment = NULL;
	33
94ec8c6b	34	void
	35	auth_clear_options(void)
	36	{
	37	no_agent_forwarding_flag = 0;
	38	no_port_forwarding_flag = 0;
	39	no_pty_flag = 0;
	40	no_x11_forwarding_flag = 0;
	41	while (custom_environment) {
	42	struct envstring *ce = custom_environment;
	43	custom_environment = ce->next;
	44	xfree(ce->s);
	45	xfree(ce);
	46	}
	47	if (forced_command) {
	48	xfree(forced_command);
	49	forced_command = NULL;
	50	}
	51	}
	52
42f11eb2	53	/*
	54	* return 1 if access is granted, 0 if not.
	55	* side effect: sets key option flags
	56	*/
38c295d6	57	int
42f11eb2	58	auth_parse_options(struct passwd pw, char options, char *file, u_long linenum)
38c295d6	59	{
	60	const char *cp;
	61	if (!options)
	62	return 1;
94ec8c6b	63
	64	/* reset options */
	65	auth_clear_options();
	66
38c295d6	67	while (options && options != ' ' && *options != '\t') {
38c295d6	68	cp = "no-port-forwarding";
d343d900	69	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	70	packet_send_debug("Port forwarding disabled.");
	71	no_port_forwarding_flag = 1;
	72	options += strlen(cp);
	73	goto next_option;
	74	}
	75	cp = "no-agent-forwarding";
d343d900	76	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	77	packet_send_debug("Agent forwarding disabled.");
	78	no_agent_forwarding_flag = 1;
	79	options += strlen(cp);
	80	goto next_option;
	81	}
	82	cp = "no-X11-forwarding";
d343d900	83	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	84	packet_send_debug("X11 forwarding disabled.");
	85	no_x11_forwarding_flag = 1;
	86	options += strlen(cp);
	87	goto next_option;
	88	}
	89	cp = "no-pty";
d343d900	90	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	91	packet_send_debug("Pty allocation disabled.");
	92	no_pty_flag = 1;
	93	options += strlen(cp);
	94	goto next_option;
	95	}
	96	cp = "command=\"";
d343d900	97	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	98	int i;
	99	options += strlen(cp);
	100	forced_command = xmalloc(strlen(options) + 1);
	101	i = 0;
	102	while (*options) {
	103	if (*options == '"')
	104	break;
	105	if (*options == '\\' && options[1] == '"') {
	106	options += 2;
	107	forced_command[i++] = '"';
	108	continue;
	109	}
	110	forced_command[i++] = *options++;
	111	}
	112	if (!*options) {
	113	debug("%.100s, line %lu: missing end quote",
42f11eb2	114	file, linenum);
38c295d6	115	packet_send_debug("%.100s, line %lu: missing end quote",
42f11eb2	116	file, linenum);
38c295d6	117	continue;
	118	}
	119	forced_command[i] = 0;
	120	packet_send_debug("Forced command: %.900s", forced_command);
	121	options++;
	122	goto next_option;
	123	}
	124	cp = "environment=\"";
d343d900	125	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	126	int i;
	127	char *s;
	128	struct envstring *new_envstring;
	129	options += strlen(cp);
	130	s = xmalloc(strlen(options) + 1);
	131	i = 0;
	132	while (*options) {
	133	if (*options == '"')
	134	break;
	135	if (*options == '\\' && options[1] == '"') {
	136	options += 2;
	137	s[i++] = '"';
	138	continue;
	139	}
	140	s[i++] = *options++;
	141	}
	142	if (!*options) {
	143	debug("%.100s, line %lu: missing end quote",
42f11eb2	144	file, linenum);
38c295d6	145	packet_send_debug("%.100s, line %lu: missing end quote",
42f11eb2	146	file, linenum);
38c295d6	147	continue;
	148	}
	149	s[i] = 0;
	150	packet_send_debug("Adding to environment: %.900s", s);
	151	debug("Adding to environment: %.900s", s);
	152	options++;
	153	new_envstring = xmalloc(sizeof(struct envstring));
	154	new_envstring->s = s;
	155	new_envstring->next = custom_environment;
	156	custom_environment = new_envstring;
	157	goto next_option;
	158	}
	159	cp = "from=\"";
d343d900	160	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	161	int mname, mip;
	162	char *patterns = xmalloc(strlen(options) + 1);
	163	int i;
	164	options += strlen(cp);
	165	i = 0;
	166	while (*options) {
	167	if (*options == '"')
	168	break;
	169	if (*options == '\\' && options[1] == '"') {
	170	options += 2;
	171	patterns[i++] = '"';
	172	continue;
	173	}
	174	patterns[i++] = *options++;
	175	}
	176	if (!*options) {
	177	debug("%.100s, line %lu: missing end quote",
42f11eb2	178	file, linenum);
38c295d6	179	packet_send_debug("%.100s, line %lu: missing end quote",
42f11eb2	180	file, linenum);
38c295d6	181	continue;
	182	}
	183	patterns[i] = 0;
	184	options++;
	185	/*
	186	* Deny access if we get a negative
	187	* match for the hostname or the ip
	188	* or if we get not match at all
	189	*/
	190	mname = match_hostname(get_canonical_hostname(),
	191	patterns, strlen(patterns));
	192	mip = match_hostname(get_remote_ipaddr(),
	193	patterns, strlen(patterns));
	194	xfree(patterns);
	195	if (mname == -1 \|\| mip == -1 \|\|
	196	(mname != 1 && mip != 1)) {
	197	log("Authentication tried for %.100s with correct key but not from a permitted host (host=%.200s, ip=%.200s).",
	198	pw->pw_name, get_canonical_hostname(),
	199	get_remote_ipaddr());
	200	packet_send_debug("Your host '%.200s' is not permitted to use this key for login.",
	201	get_canonical_hostname());
38c295d6	202	/* deny access */
	203	return 0;
	204	}
	205	/* Host name matches. */
	206	goto next_option;
	207	}
	208	next_option:
	209	/*
	210	* Skip the comma, and move to the next option
	211	* (or break out if there are no more).
	212	*/
	213	if (!*options)
	214	fatal("Bugs in auth-options.c option processing.");
	215	if (options == ' ' \|\| options == '\t')
	216	break; /* End of options. */
	217	if (*options != ',')
	218	goto bad_option;
	219	options++;
	220	/* Process the next option. */
	221	}
	222	/* grant access */
	223	return 1;
	224
	225	bad_option:
	226	log("Bad options in %.100s file, line %lu: %.50s",
42f11eb2	227	file, linenum, options);
38c295d6	228	packet_send_debug("Bad options in %.100s file, line %lu: %.50s",
42f11eb2	229	file, linenum, options);
38c295d6	230	/* deny access */
	231	return 0;
	232	}