[gssapi-openssh.git] / openssh / authfd.c

/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 * Functions for connecting the local authentication agent.
 *
 * 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".
 *
 * SSH2 implementation,
 * Copyright (c) 2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"
RCSID("$OpenBSD: authfd.c,v 1.63 2003/11/21 11:57:03 djm Exp $");

#include <openssl/evp.h>

#include "ssh.h"
#include "rsa.h"
#include "buffer.h"
#include "bufaux.h"
#include "xmalloc.h"
#include "getput.h"
#include "key.h"
#include "authfd.h"
#include "cipher.h"
#include "kex.h"
#include "compat.h"
#include "log.h"
#include "atomicio.h"

static int agent_present = 0;

/* helper */
int	decode_reply(int type);

/* macro to check for "agent failure" message */
#define agent_failed(x) \
    ((x == SSH_AGENT_FAILURE) || (x == SSH_COM_AGENT2_FAILURE) || \
    (x == SSH2_AGENT_FAILURE))

int
ssh_agent_present(void)
{
	int authfd;

	if (agent_present)
		return 1;
	if ((authfd = ssh_get_authentication_socket()) == -1)
		return 0;
	else {
		ssh_close_authentication_socket(authfd);
		return 1;
	}
}

/* Returns the number of the authentication fd, or -1 if there is none. */

int
ssh_get_authentication_socket(void)
{
	const char *authsocket;
	int sock;
	struct sockaddr_un sunaddr;

	authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
	if (!authsocket)
		return -1;

	sunaddr.sun_family = AF_UNIX;
	strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));

	sock = socket(AF_UNIX, SOCK_STREAM, 0);
	if (sock < 0)
		return -1;

	/* close on exec */
	if (fcntl(sock, F_SETFD, 1) == -1) {
		close(sock);
		return -1;
	}
	if (connect(sock, (struct sockaddr *) &sunaddr, sizeof sunaddr) < 0) {
		close(sock);
		return -1;
	}
	agent_present = 1;
	return sock;
}

static int
ssh_request_reply(AuthenticationConnection *auth, Buffer *request, Buffer *reply)
{
	int l;
	u_int len;
	char buf[1024];

	/* Get the length of the message, and format it in the buffer. */
	len = buffer_len(request);
	PUT_32BIT(buf, len);

	/* Send the length and then the packet to the agent. */
	if (atomicio(vwrite, auth->fd, buf, 4) != 4 ||
	    atomicio(vwrite, auth->fd, buffer_ptr(request),
	    buffer_len(request)) != buffer_len(request)) {
		error("Error writing to authentication socket.");
		return 0;
	}
	/*
	 * Wait for response from the agent.  First read the length of the
	 * response packet.
	 */
	len = 4;
	while (len > 0) {
		l = read(auth->fd, buf + 4 - len, len);
		if (l == -1 && (errno == EAGAIN || errno == EINTR))
			continue;
		if (l <= 0) {
			error("Error reading response length from authentication socket.");
			return 0;
		}
		len -= l;
	}

	/* Extract the length, and check it for sanity. */
	len = GET_32BIT(buf);
	if (len > 256 * 1024)
		fatal("Authentication response too long: %u", len);

	/* Read the rest of the response in to the buffer. */
	buffer_clear(reply);
	while (len > 0) {
		l = len;
		if (l > sizeof(buf))
			l = sizeof(buf);
		l = read(auth->fd, buf, l);
		if (l == -1 && (errno == EAGAIN || errno == EINTR))
			continue;
		if (l <= 0) {
			error("Error reading response from authentication socket.");
			return 0;
		}
		buffer_append(reply, buf, l);
		len -= l;
	}
	return 1;
}

/*
 * Closes the agent socket if it should be closed (depends on how it was
 * obtained).  The argument must have been returned by
 * ssh_get_authentication_socket().
 */

void
ssh_close_authentication_socket(int sock)
{
	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
		close(sock);
}

/*
 * Opens and connects a private socket for communication with the
 * authentication agent.  Returns the file descriptor (which must be
 * shut down and closed by the caller when no longer needed).
 * Returns NULL if an error occurred and the connection could not be
 * opened.
 */

AuthenticationConnection *
ssh_get_authentication_connection(void)
{
	AuthenticationConnection *auth;
	int sock;

	sock = ssh_get_authentication_socket();

	/*
	 * Fail if we couldn't obtain a connection.  This happens if we
	 * exited due to a timeout.
	 */
	if (sock < 0)
		return NULL;

	auth = xmalloc(sizeof(*auth));
	auth->fd = sock;
	buffer_init(&auth->identities);
	auth->howmany = 0;

	return auth;
}

/*
 * Closes the connection to the authentication agent and frees any associated
 * memory.
 */

void
ssh_close_authentication_connection(AuthenticationConnection *auth)
{
	buffer_free(&auth->identities);
	close(auth->fd);
	xfree(auth);
}

/* Lock/unlock agent */
int
ssh_lock_agent(AuthenticationConnection *auth, int lock, const char *password)
{
	int type;
	Buffer msg;

	buffer_init(&msg);
	buffer_put_char(&msg, lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK);
	buffer_put_cstring(&msg, password);

	if (ssh_request_reply(auth, &msg, &msg) == 0) {
		buffer_free(&msg);
		return 0;
	}
	type = buffer_get_char(&msg);
	buffer_free(&msg);
	return decode_reply(type);
}

/*
 * Returns the first authentication identity held by the agent.
 */

int
ssh_get_num_identities(AuthenticationConnection *auth, int version)
{
	int type, code1 = 0, code2 = 0;
	Buffer request;

	switch (version) {
	case 1:
		code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
		code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
		break;
	case 2:
		code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
		code2 = SSH2_AGENT_IDENTITIES_ANSWER;
		break;
	default:
		return 0;
	}

	/*
	 * Send a message to the agent requesting for a list of the
	 * identities it can represent.
	 */
	buffer_init(&request);
	buffer_put_char(&request, code1);

	buffer_clear(&auth->identities);
	if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
		buffer_free(&request);
		return 0;
	}
	buffer_free(&request);

	/* Get message type, and verify that we got a proper answer. */
	type = buffer_get_char(&auth->identities);
	if (agent_failed(type)) {
		return 0;
	} else if (type != code2) {
		fatal("Bad authentication reply message type: %d", type);
	}

	/* Get the number of entries in the response and check it for sanity. */
	auth->howmany = buffer_get_int(&auth->identities);
	if ((u_int)auth->howmany > 1024)
		fatal("Too many identities in authentication reply: %d",
		    auth->howmany);

	return auth->howmany;
}

Key *
ssh_get_first_identity(AuthenticationConnection *auth, char **comment, int version)
{
	/* get number of identities and return the first entry (if any). */
	if (ssh_get_num_identities(auth, version) > 0)
		return ssh_get_next_identity(auth, comment, version);
	return NULL;
}

Key *
ssh_get_next_identity(AuthenticationConnection *auth, char **comment, int version)
{
	u_int bits;
	u_char *blob;
	u_int blen;
	Key *key = NULL;

	/* Return failure if no more entries. */
	if (auth->howmany <= 0)
		return NULL;

	/*
	 * Get the next entry from the packet.  These will abort with a fatal
	 * error if the packet is too short or contains corrupt data.
	 */
	switch (version) {
	case 1:
		key = key_new(KEY_RSA1);
		bits = buffer_get_int(&auth->identities);
		buffer_get_bignum(&auth->identities, key->rsa->e);
		buffer_get_bignum(&auth->identities, key->rsa->n);
		*comment = buffer_get_string(&auth->identities, NULL);
		if (bits != BN_num_bits(key->rsa->n))
			logit("Warning: identity keysize mismatch: actual %d, announced %u",
			    BN_num_bits(key->rsa->n), bits);
		break;
	case 2:
		blob = buffer_get_string(&auth->identities, &blen);
		*comment = buffer_get_string(&auth->identities, NULL);
		key = key_from_blob(blob, blen);
		xfree(blob);
		break;
	default:
		return NULL;
		break;
	}
	/* Decrement the number of remaining entries. */
	auth->howmany--;
	return key;
}

/*
 * Generates a random challenge, sends it to the agent, and waits for
 * response from the agent.  Returns true (non-zero) if the agent gave the
 * correct answer, zero otherwise.  Response type selects the style of
 * response desired, with 0 corresponding to protocol version 1.0 (no longer
 * supported) and 1 corresponding to protocol version 1.1.
 */

int
ssh_decrypt_challenge(AuthenticationConnection *auth,
    Key* key, BIGNUM *challenge,
    u_char session_id[16],
    u_int response_type,
    u_char response[16])
{
	Buffer buffer;
	int success = 0;
	int i;
	int type;

	if (key->type != KEY_RSA1)
		return 0;
	if (response_type == 0) {
		logit("Compatibility with ssh protocol version 1.0 no longer supported.");
		return 0;
	}
	buffer_init(&buffer);
	buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
	buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
	buffer_put_bignum(&buffer, key->rsa->e);
	buffer_put_bignum(&buffer, key->rsa->n);
	buffer_put_bignum(&buffer, challenge);
	buffer_append(&buffer, session_id, 16);
	buffer_put_int(&buffer, response_type);

	if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
		buffer_free(&buffer);
		return 0;
	}
	type = buffer_get_char(&buffer);

	if (agent_failed(type)) {
		logit("Agent admitted failure to authenticate using the key.");
	} else if (type != SSH_AGENT_RSA_RESPONSE) {
		fatal("Bad authentication response: %d", type);
	} else {
		success = 1;
		/*
		 * Get the response from the packet.  This will abort with a
		 * fatal error if the packet is corrupt.
		 */
		for (i = 0; i < 16; i++)
			response[i] = buffer_get_char(&buffer);
	}
	buffer_free(&buffer);
	return success;
}

/* ask agent to sign data, returns -1 on error, 0 on success */
int
ssh_agent_sign(AuthenticationConnection *auth,
    Key *key,
    u_char **sigp, u_int *lenp,
    u_char *data, u_int datalen)
{
	extern int datafellows;
	Buffer msg;
	u_char *blob;
	u_int blen;
	int type, flags = 0;
	int ret = -1;

	if (key_to_blob(key, &blob, &blen) == 0)
		return -1;

	if (datafellows & SSH_BUG_SIGBLOB)
		flags = SSH_AGENT_OLD_SIGNATURE;

	buffer_init(&msg);
	buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
	buffer_put_string(&msg, blob, blen);
	buffer_put_string(&msg, data, datalen);
	buffer_put_int(&msg, flags);
	xfree(blob);

	if (ssh_request_reply(auth, &msg, &msg) == 0) {
		buffer_free(&msg);
		return -1;
	}
	type = buffer_get_char(&msg);
	if (agent_failed(type)) {
		logit("Agent admitted failure to sign using the key.");
	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
		fatal("Bad authentication response: %d", type);
	} else {
		ret = 0;
		*sigp = buffer_get_string(&msg, lenp);
	}
	buffer_free(&msg);
	return ret;
}

/* Encode key for a message to the agent. */

static void
ssh_encode_identity_rsa1(Buffer *b, RSA *key, const char *comment)
{
	buffer_put_int(b, BN_num_bits(key->n));
	buffer_put_bignum(b, key->n);
	buffer_put_bignum(b, key->e);
	buffer_put_bignum(b, key->d);
	/* To keep within the protocol: p < q for ssh. in SSL p > q */
	buffer_put_bignum(b, key->iqmp);	/* ssh key->u */
	buffer_put_bignum(b, key->q);	/* ssh key->p, SSL key->q */
	buffer_put_bignum(b, key->p);	/* ssh key->q, SSL key->p */
	buffer_put_cstring(b, comment);
}

static void
ssh_encode_identity_ssh2(Buffer *b, Key *key, const char *comment)
{
	buffer_put_cstring(b, key_ssh_name(key));
	switch (key->type) {
	case KEY_RSA:
		buffer_put_bignum2(b, key->rsa->n);
		buffer_put_bignum2(b, key->rsa->e);
		buffer_put_bignum2(b, key->rsa->d);
		buffer_put_bignum2(b, key->rsa->iqmp);
		buffer_put_bignum2(b, key->rsa->p);
		buffer_put_bignum2(b, key->rsa->q);
		break;
	case KEY_DSA:
		buffer_put_bignum2(b, key->dsa->p);
		buffer_put_bignum2(b, key->dsa->q);
		buffer_put_bignum2(b, key->dsa->g);
		buffer_put_bignum2(b, key->dsa->pub_key);
		buffer_put_bignum2(b, key->dsa->priv_key);
		break;
	}
	buffer_put_cstring(b, comment);
}

/*
 * Adds an identity to the authentication server.  This call is not meant to
 * be used by normal applications.
 */

int
ssh_add_identity_constrained(AuthenticationConnection *auth, Key *key,
    const char *comment, u_int life, u_int confirm)
{
	Buffer msg;
	int type, constrained = (life || confirm);

	buffer_init(&msg);

	switch (key->type) {
	case KEY_RSA1:
		type = constrained ?
		    SSH_AGENTC_ADD_RSA_ID_CONSTRAINED :
		    SSH_AGENTC_ADD_RSA_IDENTITY;
		buffer_put_char(&msg, type);
		ssh_encode_identity_rsa1(&msg, key->rsa, comment);
		break;
	case KEY_RSA:
	case KEY_DSA:
		type = constrained ?
		    SSH2_AGENTC_ADD_ID_CONSTRAINED :
		    SSH2_AGENTC_ADD_IDENTITY;
		buffer_put_char(&msg, type);
		ssh_encode_identity_ssh2(&msg, key, comment);
		break;
	default:
		buffer_free(&msg);
		return 0;
		break;
	}
	if (constrained) {
		if (life != 0) {
			buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
			buffer_put_int(&msg, life);
		}
		if (confirm != 0)
			buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_CONFIRM);
	}
	if (ssh_request_reply(auth, &msg, &msg) == 0) {
		buffer_free(&msg);
		return 0;
	}
	type = buffer_get_char(&msg);
	buffer_free(&msg);
	return decode_reply(type);
}

int
ssh_add_identity(AuthenticationConnection *auth, Key *key, const char *comment)
{
	return ssh_add_identity_constrained(auth, key, comment, 0, 0);
}

/*
 * Removes an identity from the authentication server.  This call is not
 * meant to be used by normal applications.
 */

int
ssh_remove_identity(AuthenticationConnection *auth, Key *key)
{
	Buffer msg;
	int type;
	u_char *blob;
	u_int blen;

	buffer_init(&msg);

	if (key->type == KEY_RSA1) {
		buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
		buffer_put_int(&msg, BN_num_bits(key->rsa->n));
		buffer_put_bignum(&msg, key->rsa->e);
		buffer_put_bignum(&msg, key->rsa->n);
	} else if (key->type == KEY_DSA || key->type == KEY_RSA) {
		key_to_blob(key, &blob, &blen);
		buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
		buffer_put_string(&msg, blob, blen);
		xfree(blob);
	} else {
		buffer_free(&msg);
		return 0;
	}
	if (ssh_request_reply(auth, &msg, &msg) == 0) {
		buffer_free(&msg);
		return 0;
	}
	type = buffer_get_char(&msg);
	buffer_free(&msg);
	return decode_reply(type);
}

int
ssh_update_card(AuthenticationConnection *auth, int add,
    const char *reader_id, const char *pin, u_int life, u_int confirm)
{
	Buffer msg;
	int type, constrained = (life || confirm);

	if (add) {
		type = constrained ?
		    SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED :
		    SSH_AGENTC_ADD_SMARTCARD_KEY;
	} else
		type = SSH_AGENTC_REMOVE_SMARTCARD_KEY;

	buffer_init(&msg);
	buffer_put_char(&msg, type);
	buffer_put_cstring(&msg, reader_id);
	buffer_put_cstring(&msg, pin);

	if (constrained) {
		if (life != 0) {
			buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
			buffer_put_int(&msg, life);
		}
		if (confirm != 0)
			buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_CONFIRM);
	}

	if (ssh_request_reply(auth, &msg, &msg) == 0) {
		buffer_free(&msg);
		return 0;
	}
	type = buffer_get_char(&msg);
	buffer_free(&msg);
	return decode_reply(type);
}

/*
 * Removes all identities from the agent.  This call is not meant to be used
 * by normal applications.
 */

int
ssh_remove_all_identities(AuthenticationConnection *auth, int version)
{
	Buffer msg;
	int type;
	int code = (version==1) ?
		SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
		SSH2_AGENTC_REMOVE_ALL_IDENTITIES;

	buffer_init(&msg);
	buffer_put_char(&msg, code);

	if (ssh_request_reply(auth, &msg, &msg) == 0) {
		buffer_free(&msg);
		return 0;
	}
	type = buffer_get_char(&msg);
	buffer_free(&msg);
	return decode_reply(type);
}

int
decode_reply(int type)
{
	switch (type) {
	case SSH_AGENT_FAILURE:
	case SSH_COM_AGENT2_FAILURE:
	case SSH2_AGENT_FAILURE:
		logit("SSH_AGENT_FAILURE");
		return 0;
	case SSH_AGENT_SUCCESS:
		return 1;
	default:
		fatal("Bad response from authentication agent: %d", type);
	}
	/* NOTREACHED */
	return 0;
}
Commit	Line	Data
3c0ef626	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
	5	* Functions for connecting the local authentication agent.
	6	*
	7	* As far as I am concerned, the code I have written for this software
	8	* can be used freely for any purpose. Any derived versions of this
	9	* software must be clearly marked as such, and if the derived work is
	10	* incompatible with the protocol description in the RFC file, it must be
	11	* called by a name other than "ssh" or "Secure Shell".
	12	*
	13	* SSH2 implementation,
	14	* Copyright (c) 2000 Markus Friedl. All rights reserved.
	15	*
	16	* Redistribution and use in source and binary forms, with or without
	17	* modification, are permitted provided that the following conditions
	18	* are met:
	19	* 1. Redistributions of source code must retain the above copyright
	20	* notice, this list of conditions and the following disclaimer.
	21	* 2. Redistributions in binary form must reproduce the above copyright
	22	* notice, this list of conditions and the following disclaimer in the
	23	* documentation and/or other materials provided with the distribution.
	24	*
	25	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	26	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	27	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	28	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	29	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	30	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	31	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	32	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	33	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	34	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	35	*/
	36
	37	#include "includes.h"
12408a1b	38	RCSID("$OpenBSD: authfd.c,v 1.63 2003/11/21 11:57:03 djm Exp $");
3c0ef626	39
	40	#include <openssl/evp.h>
	41
	42	#include "ssh.h"
	43	#include "rsa.h"
	44	#include "buffer.h"
	45	#include "bufaux.h"
	46	#include "xmalloc.h"
	47	#include "getput.h"
	48	#include "key.h"
	49	#include "authfd.h"
	50	#include "cipher.h"
	51	#include "kex.h"
	52	#include "compat.h"
	53	#include "log.h"
	54	#include "atomicio.h"
	55
41b2f314	56	static int agent_present = 0;
41b2f314	57
3c0ef626	58	/* helper */
	59	int decode_reply(int type);
	60
	61	/* macro to check for "agent failure" message */
	62	#define agent_failed(x) \
	63	((x == SSH_AGENT_FAILURE) \|\| (x == SSH_COM_AGENT2_FAILURE) \|\| \
f5799ae1	64	(x == SSH2_AGENT_FAILURE))
3c0ef626	65
41b2f314	66	int
	67	ssh_agent_present(void)
	68	{
	69	int authfd;
	70
	71	if (agent_present)
	72	return 1;
	73	if ((authfd = ssh_get_authentication_socket()) == -1)
	74	return 0;
	75	else {
	76	ssh_close_authentication_socket(authfd);
	77	return 1;
	78	}
	79	}
	80
3c0ef626	81	/* Returns the number of the authentication fd, or -1 if there is none. */
	82
	83	int
	84	ssh_get_authentication_socket(void)
	85	{
	86	const char *authsocket;
	87	int sock;
	88	struct sockaddr_un sunaddr;
	89
	90	authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
	91	if (!authsocket)
	92	return -1;
	93
	94	sunaddr.sun_family = AF_UNIX;
	95	strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
	96
	97	sock = socket(AF_UNIX, SOCK_STREAM, 0);
	98	if (sock < 0)
	99	return -1;
	100
	101	/* close on exec */
	102	if (fcntl(sock, F_SETFD, 1) == -1) {
	103	close(sock);
	104	return -1;
	105	}
	106	if (connect(sock, (struct sockaddr *) &sunaddr, sizeof sunaddr) < 0) {
	107	close(sock);
	108	return -1;
	109	}
41b2f314	110	agent_present = 1;
3c0ef626	111	return sock;
	112	}
	113
	114	static int
	115	ssh_request_reply(AuthenticationConnection auth, Buffer request, Buffer *reply)
	116	{
12408a1b	117	int l;
12408a1b	118	u_int len;
3c0ef626	119	char buf[1024];
	120
	121	/* Get the length of the message, and format it in the buffer. */
	122	len = buffer_len(request);
	123	PUT_32BIT(buf, len);
	124
	125	/* Send the length and then the packet to the agent. */
0fff78ff	126	if (atomicio(vwrite, auth->fd, buf, 4) != 4 \|\|
0fff78ff	127	atomicio(vwrite, auth->fd, buffer_ptr(request),
3c0ef626	128	buffer_len(request)) != buffer_len(request)) {
	129	error("Error writing to authentication socket.");
	130	return 0;
	131	}
	132	/*
	133	* Wait for response from the agent. First read the length of the
	134	* response packet.
	135	*/
	136	len = 4;
	137	while (len > 0) {
	138	l = read(auth->fd, buf + 4 - len, len);
	139	if (l == -1 && (errno == EAGAIN \|\| errno == EINTR))
	140	continue;
	141	if (l <= 0) {
	142	error("Error reading response length from authentication socket.");
	143	return 0;
	144	}
	145	len -= l;
	146	}
	147
	148	/* Extract the length, and check it for sanity. */
	149	len = GET_32BIT(buf);
	150	if (len > 256 * 1024)
12408a1b	151	fatal("Authentication response too long: %u", len);
3c0ef626	152
	153	/* Read the rest of the response in to the buffer. */
	154	buffer_clear(reply);
	155	while (len > 0) {
	156	l = len;
	157	if (l > sizeof(buf))
	158	l = sizeof(buf);
	159	l = read(auth->fd, buf, l);
	160	if (l == -1 && (errno == EAGAIN \|\| errno == EINTR))
	161	continue;
	162	if (l <= 0) {
	163	error("Error reading response from authentication socket.");
	164	return 0;
	165	}
680cee3b	166	buffer_append(reply, buf, l);
3c0ef626	167	len -= l;
	168	}
	169	return 1;
	170	}
	171
	172	/*
	173	* Closes the agent socket if it should be closed (depends on how it was
	174	* obtained). The argument must have been returned by
	175	* ssh_get_authentication_socket().
	176	*/
	177
	178	void
	179	ssh_close_authentication_socket(int sock)
	180	{
	181	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
	182	close(sock);
	183	}
	184
	185	/*
	186	* Opens and connects a private socket for communication with the
	187	* authentication agent. Returns the file descriptor (which must be
	188	* shut down and closed by the caller when no longer needed).
	189	* Returns NULL if an error occurred and the connection could not be
	190	* opened.
	191	*/
	192
	193	AuthenticationConnection *
	194	ssh_get_authentication_connection(void)
	195	{
	196	AuthenticationConnection *auth;
	197	int sock;
	198
	199	sock = ssh_get_authentication_socket();
	200
	201	/*
	202	* Fail if we couldn't obtain a connection. This happens if we
	203	* exited due to a timeout.
	204	*/
	205	if (sock < 0)
	206	return NULL;
	207
	208	auth = xmalloc(sizeof(*auth));
	209	auth->fd = sock;
	210	buffer_init(&auth->identities);
	211	auth->howmany = 0;
	212
	213	return auth;
	214	}
	215
	216	/*
	217	* Closes the connection to the authentication agent and frees any associated
	218	* memory.
	219	*/
	220
	221	void
	222	ssh_close_authentication_connection(AuthenticationConnection *auth)
	223	{
	224	buffer_free(&auth->identities);
	225	close(auth->fd);
	226	xfree(auth);
	227	}
	228
f5799ae1	229	/* Lock/unlock agent */
	230	int
	231	ssh_lock_agent(AuthenticationConnection auth, int lock, const char password)
	232	{
	233	int type;
	234	Buffer msg;
	235
	236	buffer_init(&msg);
	237	buffer_put_char(&msg, lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK);
	238	buffer_put_cstring(&msg, password);
	239
	240	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	241	buffer_free(&msg);
	242	return 0;
	243	}
	244	type = buffer_get_char(&msg);
	245	buffer_free(&msg);
	246	return decode_reply(type);
	247	}
	248
3c0ef626	249	/*
	250	* Returns the first authentication identity held by the agent.
	251	*/
	252
	253	int
	254	ssh_get_num_identities(AuthenticationConnection *auth, int version)
	255	{
	256	int type, code1 = 0, code2 = 0;
	257	Buffer request;
	258
e9a17296	259	switch (version) {
3c0ef626	260	case 1:
	261	code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
	262	code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
	263	break;
	264	case 2:
	265	code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
	266	code2 = SSH2_AGENT_IDENTITIES_ANSWER;
	267	break;
	268	default:
	269	return 0;
	270	}
	271
	272	/*
	273	* Send a message to the agent requesting for a list of the
	274	* identities it can represent.
	275	*/
	276	buffer_init(&request);
	277	buffer_put_char(&request, code1);
	278
	279	buffer_clear(&auth->identities);
	280	if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
	281	buffer_free(&request);
	282	return 0;
	283	}
	284	buffer_free(&request);
	285
	286	/* Get message type, and verify that we got a proper answer. */
	287	type = buffer_get_char(&auth->identities);
	288	if (agent_failed(type)) {
	289	return 0;
	290	} else if (type != code2) {
	291	fatal("Bad authentication reply message type: %d", type);
	292	}
	293
	294	/* Get the number of entries in the response and check it for sanity. */
	295	auth->howmany = buffer_get_int(&auth->identities);
12408a1b	296	if ((u_int)auth->howmany > 1024)
3c0ef626	297	fatal("Too many identities in authentication reply: %d",
	298	auth->howmany);
	299
	300	return auth->howmany;
	301	}
	302
	303	Key *
	304	ssh_get_first_identity(AuthenticationConnection auth, char *comment, int version)
	305	{
	306	/* get number of identities and return the first entry (if any). */
	307	if (ssh_get_num_identities(auth, version) > 0)
	308	return ssh_get_next_identity(auth, comment, version);
	309	return NULL;
	310	}
	311
	312	Key *
	313	ssh_get_next_identity(AuthenticationConnection auth, char *comment, int version)
	314	{
	315	u_int bits;
	316	u_char *blob;
	317	u_int blen;
	318	Key *key = NULL;
	319
	320	/* Return failure if no more entries. */
	321	if (auth->howmany <= 0)
	322	return NULL;
	323
	324	/*
	325	* Get the next entry from the packet. These will abort with a fatal
	326	* error if the packet is too short or contains corrupt data.
	327	*/
e9a17296	328	switch (version) {
3c0ef626	329	case 1:
	330	key = key_new(KEY_RSA1);
	331	bits = buffer_get_int(&auth->identities);
	332	buffer_get_bignum(&auth->identities, key->rsa->e);
	333	buffer_get_bignum(&auth->identities, key->rsa->n);
	334	*comment = buffer_get_string(&auth->identities, NULL);
	335	if (bits != BN_num_bits(key->rsa->n))
0fff78ff	336	logit("Warning: identity keysize mismatch: actual %d, announced %u",
3c0ef626	337	BN_num_bits(key->rsa->n), bits);
	338	break;
	339	case 2:
	340	blob = buffer_get_string(&auth->identities, &blen);
	341	*comment = buffer_get_string(&auth->identities, NULL);
	342	key = key_from_blob(blob, blen);
	343	xfree(blob);
	344	break;
	345	default:
	346	return NULL;
	347	break;
	348	}
	349	/* Decrement the number of remaining entries. */
	350	auth->howmany--;
	351	return key;
	352	}
	353
	354	/*
	355	* Generates a random challenge, sends it to the agent, and waits for
	356	* response from the agent. Returns true (non-zero) if the agent gave the
	357	* correct answer, zero otherwise. Response type selects the style of
	358	* response desired, with 0 corresponding to protocol version 1.0 (no longer
	359	* supported) and 1 corresponding to protocol version 1.1.
	360	*/
	361
	362	int
	363	ssh_decrypt_challenge(AuthenticationConnection *auth,
	364	Key* key, BIGNUM *challenge,
	365	u_char session_id[16],
	366	u_int response_type,
	367	u_char response[16])
	368	{
	369	Buffer buffer;
	370	int success = 0;
	371	int i;
	372	int type;
	373
	374	if (key->type != KEY_RSA1)
	375	return 0;
	376	if (response_type == 0) {
0fff78ff	377	logit("Compatibility with ssh protocol version 1.0 no longer supported.");
3c0ef626	378	return 0;
	379	}
	380	buffer_init(&buffer);
	381	buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
	382	buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
	383	buffer_put_bignum(&buffer, key->rsa->e);
	384	buffer_put_bignum(&buffer, key->rsa->n);
	385	buffer_put_bignum(&buffer, challenge);
e9a17296	386	buffer_append(&buffer, session_id, 16);
3c0ef626	387	buffer_put_int(&buffer, response_type);
	388
	389	if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
	390	buffer_free(&buffer);
	391	return 0;
	392	}
	393	type = buffer_get_char(&buffer);
	394
	395	if (agent_failed(type)) {
0fff78ff	396	logit("Agent admitted failure to authenticate using the key.");
3c0ef626	397	} else if (type != SSH_AGENT_RSA_RESPONSE) {
	398	fatal("Bad authentication response: %d", type);
	399	} else {
	400	success = 1;
	401	/*
	402	* Get the response from the packet. This will abort with a
	403	* fatal error if the packet is corrupt.
	404	*/
	405	for (i = 0; i < 16; i++)
	406	response[i] = buffer_get_char(&buffer);
	407	}
	408	buffer_free(&buffer);
	409	return success;
	410	}
	411
	412	/* ask agent to sign data, returns -1 on error, 0 on success */
	413	int
	414	ssh_agent_sign(AuthenticationConnection *auth,
	415	Key *key,
e9a17296	416	u_char *sigp, u_int lenp,
e9a17296	417	u_char *data, u_int datalen)
3c0ef626	418	{
	419	extern int datafellows;
	420	Buffer msg;
	421	u_char *blob;
	422	u_int blen;
	423	int type, flags = 0;
	424	int ret = -1;
	425
	426	if (key_to_blob(key, &blob, &blen) == 0)
	427	return -1;
	428
	429	if (datafellows & SSH_BUG_SIGBLOB)
	430	flags = SSH_AGENT_OLD_SIGNATURE;
	431
	432	buffer_init(&msg);
	433	buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
	434	buffer_put_string(&msg, blob, blen);
	435	buffer_put_string(&msg, data, datalen);
	436	buffer_put_int(&msg, flags);
	437	xfree(blob);
	438
	439	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	440	buffer_free(&msg);
	441	return -1;
	442	}
	443	type = buffer_get_char(&msg);
	444	if (agent_failed(type)) {
0fff78ff	445	logit("Agent admitted failure to sign using the key.");
3c0ef626	446	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
	447	fatal("Bad authentication response: %d", type);
	448	} else {
	449	ret = 0;
	450	*sigp = buffer_get_string(&msg, lenp);
	451	}
	452	buffer_free(&msg);
	453	return ret;
	454	}
	455
	456	/* Encode key for a message to the agent. */
	457
	458	static void
	459	ssh_encode_identity_rsa1(Buffer b, RSA key, const char *comment)
	460	{
3c0ef626	461	buffer_put_int(b, BN_num_bits(key->n));
	462	buffer_put_bignum(b, key->n);
	463	buffer_put_bignum(b, key->e);
	464	buffer_put_bignum(b, key->d);
	465	/* To keep within the protocol: p < q for ssh. in SSL p > q */
	466	buffer_put_bignum(b, key->iqmp); /* ssh key->u */
	467	buffer_put_bignum(b, key->q); /* ssh key->p, SSL key->q */
	468	buffer_put_bignum(b, key->p); /* ssh key->q, SSL key->p */
	469	buffer_put_cstring(b, comment);
	470	}
	471
	472	static void
	473	ssh_encode_identity_ssh2(Buffer b, Key key, const char *comment)
	474	{
3c0ef626	475	buffer_put_cstring(b, key_ssh_name(key));
e9a17296	476	switch (key->type) {
3c0ef626	477	case KEY_RSA:
	478	buffer_put_bignum2(b, key->rsa->n);
	479	buffer_put_bignum2(b, key->rsa->e);
	480	buffer_put_bignum2(b, key->rsa->d);
	481	buffer_put_bignum2(b, key->rsa->iqmp);
	482	buffer_put_bignum2(b, key->rsa->p);
	483	buffer_put_bignum2(b, key->rsa->q);
	484	break;
	485	case KEY_DSA:
	486	buffer_put_bignum2(b, key->dsa->p);
	487	buffer_put_bignum2(b, key->dsa->q);
	488	buffer_put_bignum2(b, key->dsa->g);
	489	buffer_put_bignum2(b, key->dsa->pub_key);
	490	buffer_put_bignum2(b, key->dsa->priv_key);
	491	break;
	492	}
	493	buffer_put_cstring(b, comment);
	494	}
	495
	496	/*
	497	* Adds an identity to the authentication server. This call is not meant to
	498	* be used by normal applications.
	499	*/
	500
	501	int
f5799ae1	502	ssh_add_identity_constrained(AuthenticationConnection auth, Key key,
6a9b3198	503	const char *comment, u_int life, u_int confirm)
3c0ef626	504	{
3c0ef626	505	Buffer msg;
6a9b3198	506	int type, constrained = (life \|\| confirm);
3c0ef626	507
	508	buffer_init(&msg);
	509
	510	switch (key->type) {
	511	case KEY_RSA1:
f5799ae1	512	type = constrained ?
	513	SSH_AGENTC_ADD_RSA_ID_CONSTRAINED :
	514	SSH_AGENTC_ADD_RSA_IDENTITY;
	515	buffer_put_char(&msg, type);
3c0ef626	516	ssh_encode_identity_rsa1(&msg, key->rsa, comment);
	517	break;
	518	case KEY_RSA:
	519	case KEY_DSA:
f5799ae1	520	type = constrained ?
	521	SSH2_AGENTC_ADD_ID_CONSTRAINED :
	522	SSH2_AGENTC_ADD_IDENTITY;
	523	buffer_put_char(&msg, type);
3c0ef626	524	ssh_encode_identity_ssh2(&msg, key, comment);
	525	break;
	526	default:
	527	buffer_free(&msg);
	528	return 0;
	529	break;
	530	}
f5799ae1	531	if (constrained) {
	532	if (life != 0) {
	533	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
	534	buffer_put_int(&msg, life);
	535	}
6a9b3198	536	if (confirm != 0)
6a9b3198	537	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_CONFIRM);
f5799ae1	538	}
3c0ef626	539	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	540	buffer_free(&msg);
	541	return 0;
	542	}
	543	type = buffer_get_char(&msg);
	544	buffer_free(&msg);
	545	return decode_reply(type);
	546	}
	547
f5799ae1	548	int
	549	ssh_add_identity(AuthenticationConnection auth, Key key, const char *comment)
	550	{
6a9b3198	551	return ssh_add_identity_constrained(auth, key, comment, 0, 0);
f5799ae1	552	}
f5799ae1	553
3c0ef626	554	/*
	555	* Removes an identity from the authentication server. This call is not
	556	* meant to be used by normal applications.
	557	*/
	558
	559	int
	560	ssh_remove_identity(AuthenticationConnection auth, Key key)
	561	{
	562	Buffer msg;
	563	int type;
	564	u_char *blob;
	565	u_int blen;
	566
	567	buffer_init(&msg);
	568
	569	if (key->type == KEY_RSA1) {
	570	buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
	571	buffer_put_int(&msg, BN_num_bits(key->rsa->n));
	572	buffer_put_bignum(&msg, key->rsa->e);
	573	buffer_put_bignum(&msg, key->rsa->n);
	574	} else if (key->type == KEY_DSA \|\| key->type == KEY_RSA) {
	575	key_to_blob(key, &blob, &blen);
	576	buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
	577	buffer_put_string(&msg, blob, blen);
	578	xfree(blob);
	579	} else {
	580	buffer_free(&msg);
	581	return 0;
	582	}
	583	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	584	buffer_free(&msg);
	585	return 0;
	586	}
	587	type = buffer_get_char(&msg);
	588	buffer_free(&msg);
	589	return decode_reply(type);
	590	}
	591
	592	int
12408a1b	593	ssh_update_card(AuthenticationConnection *auth, int add,
0fff78ff	594	const char reader_id, const char pin, u_int life, u_int confirm)
3c0ef626	595	{
3c0ef626	596	Buffer msg;
0fff78ff	597	int type, constrained = (life \|\| confirm);
	598
	599	if (add) {
	600	type = constrained ?
	601	SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED :
	602	SSH_AGENTC_ADD_SMARTCARD_KEY;
	603	} else
	604	type = SSH_AGENTC_REMOVE_SMARTCARD_KEY;
3c0ef626	605
3c0ef626	606	buffer_init(&msg);
0fff78ff	607	buffer_put_char(&msg, type);
3c0ef626	608	buffer_put_cstring(&msg, reader_id);
700318f3	609	buffer_put_cstring(&msg, pin);
12408a1b	610
0fff78ff	611	if (constrained) {
	612	if (life != 0) {
	613	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
	614	buffer_put_int(&msg, life);
	615	}
	616	if (confirm != 0)
	617	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_CONFIRM);
	618	}
	619
3c0ef626	620	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	621	buffer_free(&msg);
	622	return 0;
	623	}
	624	type = buffer_get_char(&msg);
	625	buffer_free(&msg);
	626	return decode_reply(type);
	627	}
	628
	629	/*
	630	* Removes all identities from the agent. This call is not meant to be used
	631	* by normal applications.
	632	*/
	633
	634	int
	635	ssh_remove_all_identities(AuthenticationConnection *auth, int version)
	636	{
	637	Buffer msg;
	638	int type;
	639	int code = (version==1) ?
	640	SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
	641	SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
	642
	643	buffer_init(&msg);
	644	buffer_put_char(&msg, code);
	645
	646	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	647	buffer_free(&msg);
	648	return 0;
	649	}
	650	type = buffer_get_char(&msg);
	651	buffer_free(&msg);
	652	return decode_reply(type);
	653	}
	654
	655	int
	656	decode_reply(int type)
	657	{
	658	switch (type) {
	659	case SSH_AGENT_FAILURE:
	660	case SSH_COM_AGENT2_FAILURE:
	661	case SSH2_AGENT_FAILURE:
0fff78ff	662	logit("SSH_AGENT_FAILURE");
3c0ef626	663	return 0;
	664	case SSH_AGENT_SUCCESS:
	665	return 1;
	666	default:
	667	fatal("Bad response from authentication agent: %d", type);
	668	}
	669	/* NOTREACHED */
	670	return 0;
	671	}