[openssh.git] / 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 1.65 2005/05/24 17:32:43 avsm 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.
	 */
	if (atomicio(read, auth->fd, buf, 4) != 4) {
	    error("Error reading response length from authentication socket.");
	    return 0;
	}

	/* 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);
		if (atomicio(read, auth->fd, buf, l) != l) {
			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
8efc0c15	1	/*
5260325f	2	* Author: Tatu Ylonen <ylo@cs.hut.fi>
5260325f	3	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5260325f	4	* All rights reserved
5260325f	5	* Functions for connecting the local authentication agent.
6ae2364d	6	*
bcbf86ec	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	*
2e73a022	13	* SSH2 implementation,
bcbf86ec	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.
2e73a022	24	*
bcbf86ec	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.
5260325f	35	*/
8efc0c15	36
8efc0c15	37	#include "includes.h"
05624c18	38	RCSID("$OpenBSD: authfd.c,v 1.65 2005/05/24 17:32:43 avsm Exp $");
42f11eb2	39
42f11eb2	40	#include <openssl/evp.h>
8efc0c15	41
	42	#include "ssh.h"
	43	#include "rsa.h"
8efc0c15	44	#include "buffer.h"
	45	#include "bufaux.h"
	46	#include "xmalloc.h"
	47	#include "getput.h"
4c8722d9	48	#include "key.h"
4c8722d9	49	#include "authfd.h"
42f11eb2	50	#include "cipher.h"
4c8722d9	51	#include "kex.h"
188adeb2	52	#include "compat.h"
42f11eb2	53	#include "log.h"
42f11eb2	54	#include "atomicio.h"
8efc0c15	55
8b10e20e	56	static int agent_present = 0;
8b10e20e	57
089fbbd2	58	/* helper */
c345cf9d	59	int decode_reply(int type);
089fbbd2	60
94ec8c6b	61	/* macro to check for "agent failure" message */
94ec8c6b	62	#define agent_failed(x) \
65e683bd	63	((x == SSH_AGENT_FAILURE) \|\| (x == SSH_COM_AGENT2_FAILURE) \|\| \
7203d6bb	64	(x == SSH2_AGENT_FAILURE))
94ec8c6b	65
8b10e20e	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
8efc0c15	81	/* Returns the number of the authentication fd, or -1 if there is none. */
	82
	83	int
1e3b8b07	84	ssh_get_authentication_socket(void)
8efc0c15	85	{
5260325f	86	const char *authsocket;
f34f05d5	87	int sock;
5260325f	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	}
f34f05d5	106	if (connect(sock, (struct sockaddr *) &sunaddr, sizeof sunaddr) < 0) {
5260325f	107	close(sock);
	108	return -1;
	109	}
8b10e20e	110	agent_present = 1;
5260325f	111	return sock;
8efc0c15	112	}
8efc0c15	113
396c147e	114	static int
2e73a022	115	ssh_request_reply(AuthenticationConnection auth, Buffer request, Buffer *reply)
c345cf9d	116	{
bb92e5cc	117	int l;
bb92e5cc	118	u_int len;
c345cf9d	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. */
dc54438a	126	if (atomicio(vwrite, auth->fd, buf, 4) != 4 \|\|
dc54438a	127	atomicio(vwrite, auth->fd, buffer_ptr(request),
c345cf9d	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	*/
f581b6e8	136	if (atomicio(read, auth->fd, buf, 4) != 4) {
	137	error("Error reading response length from authentication socket.");
	138	return 0;
c345cf9d	139	}
	140
	141	/* Extract the length, and check it for sanity. */
	142	len = GET_32BIT(buf);
	143	if (len > 256 * 1024)
bb92e5cc	144	fatal("Authentication response too long: %u", len);
c345cf9d	145
	146	/* Read the rest of the response in to the buffer. */
	147	buffer_clear(reply);
	148	while (len > 0) {
	149	l = len;
	150	if (l > sizeof(buf))
	151	l = sizeof(buf);
05624c18	152	if (atomicio(read, auth->fd, buf, l) != l) {
c345cf9d	153	error("Error reading response from authentication socket.");
	154	return 0;
	155	}
6c69a6a9	156	buffer_append(reply, buf, l);
c345cf9d	157	len -= l;
	158	}
	159	return 1;
	160	}
	161
aa3378df	162	/*
	163	* Closes the agent socket if it should be closed (depends on how it was
	164	* obtained). The argument must have been returned by
	165	* ssh_get_authentication_socket().
	166	*/
8efc0c15	167
6ae2364d	168	void
5260325f	169	ssh_close_authentication_socket(int sock)
8efc0c15	170	{
5260325f	171	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
5260325f	172	close(sock);
8efc0c15	173	}
8efc0c15	174
aa3378df	175	/*
	176	* Opens and connects a private socket for communication with the
	177	* authentication agent. Returns the file descriptor (which must be
	178	* shut down and closed by the caller when no longer needed).
	179	* Returns NULL if an error occurred and the connection could not be
	180	* opened.
	181	*/
8efc0c15	182
5260325f	183	AuthenticationConnection *
1e3b8b07	184	ssh_get_authentication_connection(void)
8efc0c15	185	{
5260325f	186	AuthenticationConnection *auth;
	187	int sock;
	188
	189	sock = ssh_get_authentication_socket();
	190
aa3378df	191	/*
	192	* Fail if we couldn't obtain a connection. This happens if we
	193	* exited due to a timeout.
	194	*/
5260325f	195	if (sock < 0)
	196	return NULL;
	197
5260325f	198	auth = xmalloc(sizeof(*auth));
5260325f	199	auth->fd = sock;
5260325f	200	buffer_init(&auth->identities);
	201	auth->howmany = 0;
	202
	203	return auth;
8efc0c15	204	}
8efc0c15	205
aa3378df	206	/*
	207	* Closes the connection to the authentication agent and frees any associated
	208	* memory.
	209	*/
8efc0c15	210
6ae2364d	211	void
2e73a022	212	ssh_close_authentication_connection(AuthenticationConnection *auth)
8efc0c15	213	{
2e73a022	214	buffer_free(&auth->identities);
	215	close(auth->fd);
	216	xfree(auth);
8efc0c15	217	}
8efc0c15	218
3db7f994	219	/* Lock/unlock agent */
	220	int
	221	ssh_lock_agent(AuthenticationConnection auth, int lock, const char password)
	222	{
	223	int type;
	224	Buffer msg;
	225
	226	buffer_init(&msg);
	227	buffer_put_char(&msg, lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK);
	228	buffer_put_cstring(&msg, password);
	229
	230	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	231	buffer_free(&msg);
	232	return 0;
	233	}
	234	type = buffer_get_char(&msg);
	235	buffer_free(&msg);
	236	return decode_reply(type);
	237	}
	238
aa3378df	239	/*
aa3378df	240	* Returns the first authentication identity held by the agent.
aa3378df	241	*/
8efc0c15	242
fa08c86b	243	int
fa08c86b	244	ssh_get_num_identities(AuthenticationConnection *auth, int version)
8efc0c15	245	{
2e73a022	246	int type, code1 = 0, code2 = 0;
c345cf9d	247	Buffer request;
2e73a022	248
6aacefa7	249	switch (version) {
2e73a022	250	case 1:
	251	code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
	252	code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
	253	break;
	254	case 2:
	255	code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
	256	code2 = SSH2_AGENT_IDENTITIES_ANSWER;
	257	break;
	258	default:
fa08c86b	259	return 0;
2e73a022	260	}
5260325f	261
aa3378df	262	/*
	263	* Send a message to the agent requesting for a list of the
	264	* identities it can represent.
	265	*/
c345cf9d	266	buffer_init(&request);
2e73a022	267	buffer_put_char(&request, code1);
5260325f	268
5260325f	269	buffer_clear(&auth->identities);
c345cf9d	270	if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
c345cf9d	271	buffer_free(&request);
fa08c86b	272	return 0;
8efc0c15	273	}
c345cf9d	274	buffer_free(&request);
5260325f	275
5260325f	276	/* Get message type, and verify that we got a proper answer. */
c345cf9d	277	type = buffer_get_char(&auth->identities);
94ec8c6b	278	if (agent_failed(type)) {
fa08c86b	279	return 0;
2e73a022	280	} else if (type != code2) {
c345cf9d	281	fatal("Bad authentication reply message type: %d", type);
2e73a022	282	}
5260325f	283
	284	/* Get the number of entries in the response and check it for sanity. */
	285	auth->howmany = buffer_get_int(&auth->identities);
bb92e5cc	286	if ((u_int)auth->howmany > 1024)
54b974dc	287	fatal("Too many identities in authentication reply: %d",
c345cf9d	288	auth->howmany);
5260325f	289
fa08c86b	290	return auth->howmany;
	291	}
	292
	293	Key *
	294	ssh_get_first_identity(AuthenticationConnection auth, char *comment, int version)
	295	{
	296	/* get number of identities and return the first entry (if any). */
	297	if (ssh_get_num_identities(auth, version) > 0)
	298	return ssh_get_next_identity(auth, comment, version);
	299	return NULL;
8efc0c15	300	}
8efc0c15	301
2e73a022	302	Key *
2e73a022	303	ssh_get_next_identity(AuthenticationConnection auth, char *comment, int version)
8efc0c15	304	{
1e3b8b07	305	u_int bits;
	306	u_char *blob;
	307	u_int blen;
2e73a022	308	Key *key = NULL;
4d195447	309
5260325f	310	/* Return failure if no more entries. */
5260325f	311	if (auth->howmany <= 0)
2e73a022	312	return NULL;
8efc0c15	313
aa3378df	314	/*
	315	* Get the next entry from the packet. These will abort with a fatal
	316	* error if the packet is too short or contains corrupt data.
	317	*/
6aacefa7	318	switch (version) {
2e73a022	319	case 1:
fa08c86b	320	key = key_new(KEY_RSA1);
2e73a022	321	bits = buffer_get_int(&auth->identities);
	322	buffer_get_bignum(&auth->identities, key->rsa->e);
	323	buffer_get_bignum(&auth->identities, key->rsa->n);
	324	*comment = buffer_get_string(&auth->identities, NULL);
	325	if (bits != BN_num_bits(key->rsa->n))
bbe88b6d	326	logit("Warning: identity keysize mismatch: actual %d, announced %u",
2e73a022	327	BN_num_bits(key->rsa->n), bits);
	328	break;
	329	case 2:
	330	blob = buffer_get_string(&auth->identities, &blen);
	331	*comment = buffer_get_string(&auth->identities, NULL);
fa08c86b	332	key = key_from_blob(blob, blen);
2e73a022	333	xfree(blob);
	334	break;
	335	default:
	336	return NULL;
	337	break;
	338	}
5260325f	339	/* Decrement the number of remaining entries. */
5260325f	340	auth->howmany--;
2e73a022	341	return key;
8efc0c15	342	}
8efc0c15	343
aa3378df	344	/*
	345	* Generates a random challenge, sends it to the agent, and waits for
	346	* response from the agent. Returns true (non-zero) if the agent gave the
	347	* correct answer, zero otherwise. Response type selects the style of
	348	* response desired, with 0 corresponding to protocol version 1.0 (no longer
	349	* supported) and 1 corresponding to protocol version 1.1.
	350	*/
8efc0c15	351
	352	int
	353	ssh_decrypt_challenge(AuthenticationConnection *auth,
2e73a022	354	Key* key, BIGNUM *challenge,
1e3b8b07	355	u_char session_id[16],
	356	u_int response_type,
	357	u_char response[16])
8efc0c15	358	{
5260325f	359	Buffer buffer;
c345cf9d	360	int success = 0;
	361	int i;
	362	int type;
5260325f	363
fa08c86b	364	if (key->type != KEY_RSA1)
2e73a022	365	return 0;
2e73a022	366	if (response_type == 0) {
bbe88b6d	367	logit("Compatibility with ssh protocol version 1.0 no longer supported.");
2e73a022	368	return 0;
2e73a022	369	}
5260325f	370	buffer_init(&buffer);
c345cf9d	371	buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
2e73a022	372	buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
	373	buffer_put_bignum(&buffer, key->rsa->e);
	374	buffer_put_bignum(&buffer, key->rsa->n);
5260325f	375	buffer_put_bignum(&buffer, challenge);
e6207598	376	buffer_append(&buffer, session_id, 16);
5260325f	377	buffer_put_int(&buffer, response_type);
5260325f	378
c345cf9d	379	if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
5260325f	380	buffer_free(&buffer);
	381	return 0;
	382	}
c345cf9d	383	type = buffer_get_char(&buffer);
5260325f	384
94ec8c6b	385	if (agent_failed(type)) {
bbe88b6d	386	logit("Agent admitted failure to authenticate using the key.");
c345cf9d	387	} else if (type != SSH_AGENT_RSA_RESPONSE) {
	388	fatal("Bad authentication response: %d", type);
	389	} else {
	390	success = 1;
	391	/*
	392	* Get the response from the packet. This will abort with a
	393	* fatal error if the packet is corrupt.
	394	*/
	395	for (i = 0; i < 16; i++)
	396	response[i] = buffer_get_char(&buffer);
8efc0c15	397	}
5260325f	398	buffer_free(&buffer);
c345cf9d	399	return success;
5260325f	400	}
8efc0c15	401
2e73a022	402	/* ask agent to sign data, returns -1 on error, 0 on success */
	403	int
	404	ssh_agent_sign(AuthenticationConnection *auth,
	405	Key *key,
c66f9d0e	406	u_char *sigp, u_int lenp,
c66f9d0e	407	u_char *data, u_int datalen)
2e73a022	408	{
188adeb2	409	extern int datafellows;
2e73a022	410	Buffer msg;
1e3b8b07	411	u_char *blob;
1e3b8b07	412	u_int blen;
188adeb2	413	int type, flags = 0;
2e73a022	414	int ret = -1;
2e73a022	415
fa08c86b	416	if (key_to_blob(key, &blob, &blen) == 0)
2e73a022	417	return -1;
2e73a022	418
188adeb2	419	if (datafellows & SSH_BUG_SIGBLOB)
	420	flags = SSH_AGENT_OLD_SIGNATURE;
	421
2e73a022	422	buffer_init(&msg);
	423	buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
	424	buffer_put_string(&msg, blob, blen);
	425	buffer_put_string(&msg, data, datalen);
188adeb2	426	buffer_put_int(&msg, flags);
2e73a022	427	xfree(blob);
	428
	429	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	430	buffer_free(&msg);
	431	return -1;
	432	}
	433	type = buffer_get_char(&msg);
94ec8c6b	434	if (agent_failed(type)) {
bbe88b6d	435	logit("Agent admitted failure to sign using the key.");
2e73a022	436	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
	437	fatal("Bad authentication response: %d", type);
	438	} else {
	439	ret = 0;
	440	*sigp = buffer_get_string(&msg, lenp);
	441	}
	442	buffer_free(&msg);
	443	return ret;
	444	}
	445
4c8722d9	446	/* Encode key for a message to the agent. */
4c8722d9	447
396c147e	448	static void
fa08c86b	449	ssh_encode_identity_rsa1(Buffer b, RSA key, const char *comment)
4c8722d9	450	{
4c8722d9	451	buffer_put_int(b, BN_num_bits(key->n));
	452	buffer_put_bignum(b, key->n);
	453	buffer_put_bignum(b, key->e);
	454	buffer_put_bignum(b, key->d);
	455	/* To keep within the protocol: p < q for ssh. in SSL p > q */
	456	buffer_put_bignum(b, key->iqmp); /* ssh key->u */
	457	buffer_put_bignum(b, key->q); /* ssh key->p, SSL key->q */
	458	buffer_put_bignum(b, key->p); /* ssh key->q, SSL key->p */
449c5ba5	459	buffer_put_cstring(b, comment);
4c8722d9	460	}
4c8722d9	461
396c147e	462	static void
fa08c86b	463	ssh_encode_identity_ssh2(Buffer b, Key key, const char *comment)
4c8722d9	464	{
fa08c86b	465	buffer_put_cstring(b, key_ssh_name(key));
6aacefa7	466	switch (key->type) {
fa08c86b	467	case KEY_RSA:
	468	buffer_put_bignum2(b, key->rsa->n);
	469	buffer_put_bignum2(b, key->rsa->e);
	470	buffer_put_bignum2(b, key->rsa->d);
	471	buffer_put_bignum2(b, key->rsa->iqmp);
	472	buffer_put_bignum2(b, key->rsa->p);
	473	buffer_put_bignum2(b, key->rsa->q);
	474	break;
	475	case KEY_DSA:
	476	buffer_put_bignum2(b, key->dsa->p);
	477	buffer_put_bignum2(b, key->dsa->q);
	478	buffer_put_bignum2(b, key->dsa->g);
	479	buffer_put_bignum2(b, key->dsa->pub_key);
	480	buffer_put_bignum2(b, key->dsa->priv_key);
	481	break;
	482	}
	483	buffer_put_cstring(b, comment);
4c8722d9	484	}
4c8722d9	485
aa3378df	486	/*
	487	* Adds an identity to the authentication server. This call is not meant to
	488	* be used by normal applications.
	489	*/
8efc0c15	490
6ae2364d	491	int
ee900f87	492	ssh_add_identity_constrained(AuthenticationConnection auth, Key key,
c4087616	493	const char *comment, u_int life, u_int confirm)
8efc0c15	494	{
2e73a022	495	Buffer msg;
c4087616	496	int type, constrained = (life \|\| confirm);
5260325f	497
2e73a022	498	buffer_init(&msg);
4c8722d9	499
4c8722d9	500	switch (key->type) {
fa08c86b	501	case KEY_RSA1:
ee900f87	502	type = constrained ?
	503	SSH_AGENTC_ADD_RSA_ID_CONSTRAINED :
	504	SSH_AGENTC_ADD_RSA_IDENTITY;
	505	buffer_put_char(&msg, type);
fa08c86b	506	ssh_encode_identity_rsa1(&msg, key->rsa, comment);
4c8722d9	507	break;
fa08c86b	508	case KEY_RSA:
4c8722d9	509	case KEY_DSA:
ee900f87	510	type = constrained ?
	511	SSH2_AGENTC_ADD_ID_CONSTRAINED :
	512	SSH2_AGENTC_ADD_IDENTITY;
	513	buffer_put_char(&msg, type);
fa08c86b	514	ssh_encode_identity_ssh2(&msg, key, comment);
4c8722d9	515	break;
4c8722d9	516	default:
2e73a022	517	buffer_free(&msg);
4c8722d9	518	return 0;
	519	break;
	520	}
ee900f87	521	if (constrained) {
	522	if (life != 0) {
	523	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
	524	buffer_put_int(&msg, life);
	525	}
c4087616	526	if (confirm != 0)
c4087616	527	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_CONFIRM);
ee900f87	528	}
2e73a022	529	if (ssh_request_reply(auth, &msg, &msg) == 0) {
2e73a022	530	buffer_free(&msg);
5260325f	531	return 0;
5260325f	532	}
2e73a022	533	type = buffer_get_char(&msg);
2e73a022	534	buffer_free(&msg);
c345cf9d	535	return decode_reply(type);
5260325f	536	}
5260325f	537
ee900f87	538	int
	539	ssh_add_identity(AuthenticationConnection auth, Key key, const char *comment)
	540	{
c4087616	541	return ssh_add_identity_constrained(auth, key, comment, 0, 0);
ee900f87	542	}
ee900f87	543
aa3378df	544	/*
	545	* Removes an identity from the authentication server. This call is not
	546	* meant to be used by normal applications.
	547	*/
8efc0c15	548
6ae2364d	549	int
2e73a022	550	ssh_remove_identity(AuthenticationConnection auth, Key key)
8efc0c15	551	{
2e73a022	552	Buffer msg;
c345cf9d	553	int type;
1e3b8b07	554	u_char *blob;
1e3b8b07	555	u_int blen;
2e73a022	556
	557	buffer_init(&msg);
	558
fa08c86b	559	if (key->type == KEY_RSA1) {
2e73a022	560	buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
	561	buffer_put_int(&msg, BN_num_bits(key->rsa->n));
	562	buffer_put_bignum(&msg, key->rsa->e);
	563	buffer_put_bignum(&msg, key->rsa->n);
fa08c86b	564	} else if (key->type == KEY_DSA \|\| key->type == KEY_RSA) {
fa08c86b	565	key_to_blob(key, &blob, &blen);
2e73a022	566	buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
	567	buffer_put_string(&msg, blob, blen);
	568	xfree(blob);
	569	} else {
	570	buffer_free(&msg);
5260325f	571	return 0;
5260325f	572	}
2e73a022	573	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	574	buffer_free(&msg);
	575	return 0;
	576	}
	577	type = buffer_get_char(&msg);
	578	buffer_free(&msg);
c345cf9d	579	return decode_reply(type);
5260325f	580	}
5260325f	581
983def13	582	int
aff51935	583	ssh_update_card(AuthenticationConnection *auth, int add,
ca719034	584	const char reader_id, const char pin, u_int life, u_int confirm)
983def13	585	{
983def13	586	Buffer msg;
ca719034	587	int type, constrained = (life \|\| confirm);
	588
	589	if (add) {
	590	type = constrained ?
	591	SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED :
	592	SSH_AGENTC_ADD_SMARTCARD_KEY;
	593	} else
	594	type = SSH_AGENTC_REMOVE_SMARTCARD_KEY;
983def13	595
983def13	596	buffer_init(&msg);
ca719034	597	buffer_put_char(&msg, type);
9ff6f66f	598	buffer_put_cstring(&msg, reader_id);
76139bd8	599	buffer_put_cstring(&msg, pin);
b6453d99	600
ca719034	601	if (constrained) {
	602	if (life != 0) {
	603	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
	604	buffer_put_int(&msg, life);
	605	}
	606	if (confirm != 0)
	607	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_CONFIRM);
	608	}
	609
983def13	610	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	611	buffer_free(&msg);
	612	return 0;
	613	}
	614	type = buffer_get_char(&msg);
	615	buffer_free(&msg);
	616	return decode_reply(type);
	617	}
	618
aa3378df	619	/*
	620	* Removes all identities from the agent. This call is not meant to be used
	621	* by normal applications.
	622	*/
8efc0c15	623
6ae2364d	624	int
2e73a022	625	ssh_remove_all_identities(AuthenticationConnection *auth, int version)
8efc0c15	626	{
2e73a022	627	Buffer msg;
c345cf9d	628	int type;
2e73a022	629	int code = (version==1) ?
	630	SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
	631	SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
5260325f	632
2e73a022	633	buffer_init(&msg);
2e73a022	634	buffer_put_char(&msg, code);
5260325f	635
2e73a022	636	if (ssh_request_reply(auth, &msg, &msg) == 0) {
2e73a022	637	buffer_free(&msg);
5260325f	638	return 0;
5260325f	639	}
2e73a022	640	type = buffer_get_char(&msg);
2e73a022	641	buffer_free(&msg);
c345cf9d	642	return decode_reply(type);
089fbbd2	643	}
089fbbd2	644
2b87da3b	645	int
c345cf9d	646	decode_reply(int type)
089fbbd2	647	{
5260325f	648	switch (type) {
5260325f	649	case SSH_AGENT_FAILURE:
94ec8c6b	650	case SSH_COM_AGENT2_FAILURE:
65e683bd	651	case SSH2_AGENT_FAILURE:
bbe88b6d	652	logit("SSH_AGENT_FAILURE");
5260325f	653	return 0;
5260325f	654	case SSH_AGENT_SUCCESS:
5260325f	655	return 1;
5260325f	656	default:
089fbbd2	657	fatal("Bad response from authentication agent: %d", type);
8efc0c15	658	}
5260325f	659	/* NOTREACHED */
	660	return 0;
	661	}