[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 1.8 2001/01/13 18:38:00 markus Exp $");

#include "ssh.h"
#include "packet.h"
#include "xmalloc.h"
#include "match.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, 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",
				    SSH_USER_PERMITTED_KEYS, linenum);
				packet_send_debug("%.100s, line %lu: missing end quote",
				    SSH_USER_PERMITTED_KEYS, 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",
				    SSH_USER_PERMITTED_KEYS, linenum);
				packet_send_debug("%.100s, line %lu: missing end quote",
				    SSH_USER_PERMITTED_KEYS, 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",
				    SSH_USER_PERMITTED_KEYS, linenum);
				packet_send_debug("%.100s, line %lu: missing end quote",
				    SSH_USER_PERMITTED_KEYS, 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",
	    SSH_USER_PERMITTED_KEYS, linenum, options);
	packet_send_debug("Bad options in %.100s file, line %lu: %.50s",
	    SSH_USER_PERMITTED_KEYS, 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"
b5c334cc	13	RCSID("$OpenBSD: auth-options.c,v 1.8 2001/01/13 18:38:00 markus Exp $");
38c295d6	14
	15	#include "ssh.h"
	16	#include "packet.h"
	17	#include "xmalloc.h"
	18	#include "match.h"
	19
	20	/* Flags set authorized_keys flags */
	21	int no_port_forwarding_flag = 0;
	22	int no_agent_forwarding_flag = 0;
	23	int no_x11_forwarding_flag = 0;
	24	int no_pty_flag = 0;
	25
	26	/* "command=" option. */
	27	char *forced_command = NULL;
	28
	29	/* "environment=" options. */
	30	struct envstring *custom_environment = NULL;
	31
94ec8c6b	32	void
	33	auth_clear_options(void)
	34	{
	35	no_agent_forwarding_flag = 0;
	36	no_port_forwarding_flag = 0;
	37	no_pty_flag = 0;
	38	no_x11_forwarding_flag = 0;
	39	while (custom_environment) {
	40	struct envstring *ce = custom_environment;
	41	custom_environment = ce->next;
	42	xfree(ce->s);
	43	xfree(ce);
	44	}
	45	if (forced_command) {
	46	xfree(forced_command);
	47	forced_command = NULL;
	48	}
	49	}
	50
38c295d6	51	/* return 1 if access is granted, 0 if not. side effect: sets key option flags */
38c295d6	52	int
1e3b8b07	53	auth_parse_options(struct passwd pw, char options, u_long linenum)
38c295d6	54	{
	55	const char *cp;
	56	if (!options)
	57	return 1;
94ec8c6b	58
	59	/* reset options */
	60	auth_clear_options();
	61
38c295d6	62	while (options && options != ' ' && *options != '\t') {
38c295d6	63	cp = "no-port-forwarding";
d343d900	64	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	65	packet_send_debug("Port forwarding disabled.");
	66	no_port_forwarding_flag = 1;
	67	options += strlen(cp);
	68	goto next_option;
	69	}
	70	cp = "no-agent-forwarding";
d343d900	71	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	72	packet_send_debug("Agent forwarding disabled.");
	73	no_agent_forwarding_flag = 1;
	74	options += strlen(cp);
	75	goto next_option;
	76	}
	77	cp = "no-X11-forwarding";
d343d900	78	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	79	packet_send_debug("X11 forwarding disabled.");
	80	no_x11_forwarding_flag = 1;
	81	options += strlen(cp);
	82	goto next_option;
	83	}
	84	cp = "no-pty";
d343d900	85	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	86	packet_send_debug("Pty allocation disabled.");
	87	no_pty_flag = 1;
	88	options += strlen(cp);
	89	goto next_option;
	90	}
	91	cp = "command=\"";
d343d900	92	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	93	int i;
	94	options += strlen(cp);
	95	forced_command = xmalloc(strlen(options) + 1);
	96	i = 0;
	97	while (*options) {
	98	if (*options == '"')
	99	break;
	100	if (*options == '\\' && options[1] == '"') {
	101	options += 2;
	102	forced_command[i++] = '"';
	103	continue;
	104	}
	105	forced_command[i++] = *options++;
	106	}
	107	if (!*options) {
	108	debug("%.100s, line %lu: missing end quote",
94ec8c6b	109	SSH_USER_PERMITTED_KEYS, linenum);
38c295d6	110	packet_send_debug("%.100s, line %lu: missing end quote",
94ec8c6b	111	SSH_USER_PERMITTED_KEYS, linenum);
38c295d6	112	continue;
	113	}
	114	forced_command[i] = 0;
	115	packet_send_debug("Forced command: %.900s", forced_command);
	116	options++;
	117	goto next_option;
	118	}
	119	cp = "environment=\"";
d343d900	120	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	121	int i;
	122	char *s;
	123	struct envstring *new_envstring;
	124	options += strlen(cp);
	125	s = xmalloc(strlen(options) + 1);
	126	i = 0;
	127	while (*options) {
	128	if (*options == '"')
	129	break;
	130	if (*options == '\\' && options[1] == '"') {
	131	options += 2;
	132	s[i++] = '"';
	133	continue;
	134	}
	135	s[i++] = *options++;
	136	}
	137	if (!*options) {
	138	debug("%.100s, line %lu: missing end quote",
94ec8c6b	139	SSH_USER_PERMITTED_KEYS, linenum);
38c295d6	140	packet_send_debug("%.100s, line %lu: missing end quote",
94ec8c6b	141	SSH_USER_PERMITTED_KEYS, linenum);
38c295d6	142	continue;
	143	}
	144	s[i] = 0;
	145	packet_send_debug("Adding to environment: %.900s", s);
	146	debug("Adding to environment: %.900s", s);
	147	options++;
	148	new_envstring = xmalloc(sizeof(struct envstring));
	149	new_envstring->s = s;
	150	new_envstring->next = custom_environment;
	151	custom_environment = new_envstring;
	152	goto next_option;
	153	}
	154	cp = "from=\"";
d343d900	155	if (strncasecmp(options, cp, strlen(cp)) == 0) {
38c295d6	156	int mname, mip;
	157	char *patterns = xmalloc(strlen(options) + 1);
	158	int i;
	159	options += strlen(cp);
	160	i = 0;
	161	while (*options) {
	162	if (*options == '"')
	163	break;
	164	if (*options == '\\' && options[1] == '"') {
	165	options += 2;
	166	patterns[i++] = '"';
	167	continue;
	168	}
	169	patterns[i++] = *options++;
	170	}
	171	if (!*options) {
	172	debug("%.100s, line %lu: missing end quote",
	173	SSH_USER_PERMITTED_KEYS, linenum);
	174	packet_send_debug("%.100s, line %lu: missing end quote",
	175	SSH_USER_PERMITTED_KEYS, linenum);
	176	continue;
	177	}
	178	patterns[i] = 0;
	179	options++;
	180	/*
	181	* Deny access if we get a negative
	182	* match for the hostname or the ip
	183	* or if we get not match at all
	184	*/
	185	mname = match_hostname(get_canonical_hostname(),
	186	patterns, strlen(patterns));
	187	mip = match_hostname(get_remote_ipaddr(),
	188	patterns, strlen(patterns));
	189	xfree(patterns);
	190	if (mname == -1 \|\| mip == -1 \|\|
	191	(mname != 1 && mip != 1)) {
	192	log("Authentication tried for %.100s with correct key but not from a permitted host (host=%.200s, ip=%.200s).",
	193	pw->pw_name, get_canonical_hostname(),
	194	get_remote_ipaddr());
	195	packet_send_debug("Your host '%.200s' is not permitted to use this key for login.",
	196	get_canonical_hostname());
38c295d6	197	/* deny access */
	198	return 0;
	199	}
	200	/* Host name matches. */
	201	goto next_option;
	202	}
	203	next_option:
	204	/*
	205	* Skip the comma, and move to the next option
	206	* (or break out if there are no more).
	207	*/
	208	if (!*options)
	209	fatal("Bugs in auth-options.c option processing.");
	210	if (options == ' ' \|\| options == '\t')
	211	break; /* End of options. */
	212	if (*options != ',')
	213	goto bad_option;
	214	options++;
	215	/* Process the next option. */
	216	}
	217	/* grant access */
	218	return 1;
	219
	220	bad_option:
	221	log("Bad options in %.100s file, line %lu: %.50s",
	222	SSH_USER_PERMITTED_KEYS, linenum, options);
	223	packet_send_debug("Bad options in %.100s file, line %lu: %.50s",
	224	SSH_USER_PERMITTED_KEYS, linenum, options);
	225	/* deny access */
	226	return 0;
	227	}