[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 1.55 2002/06/19 00:27:55 deraadt 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"

/* 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))

/* 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;
	}
	return sock;
}

static int
ssh_request_reply(AuthenticationConnection *auth, Buffer *request, Buffer *reply)
{
	int l, 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(write, auth->fd, buf, 4) != 4 ||
	    atomicio(write, 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: %d", 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, (char *) 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 (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))
			log("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) {
		log("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)) {
		log("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)) {
		log("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)
{
	Buffer msg;
	int type, constrained = (life != 0);

	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 (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);
}

/*
 * 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)
{
	Buffer msg;
	int type;

	buffer_init(&msg);
	buffer_put_char(&msg, add ? SSH_AGENTC_ADD_SMARTCARD_KEY :
	    SSH_AGENTC_REMOVE_SMARTCARD_KEY);
	buffer_put_cstring(&msg, reader_id);
	buffer_put_cstring(&msg, pin);
	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:
		log("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"
f5799ae1	38	RCSID("$OpenBSD: authfd.c,v 1.55 2002/06/19 00:27:55 deraadt 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
	56	/* helper */
	57	int decode_reply(int type);
	58
	59	/* macro to check for "agent failure" message */
	60	#define agent_failed(x) \
	61	((x == SSH_AGENT_FAILURE) \|\| (x == SSH_COM_AGENT2_FAILURE) \|\| \
f5799ae1	62	(x == SSH2_AGENT_FAILURE))
3c0ef626	63
	64	/* Returns the number of the authentication fd, or -1 if there is none. */
	65
	66	int
	67	ssh_get_authentication_socket(void)
	68	{
	69	const char *authsocket;
	70	int sock;
	71	struct sockaddr_un sunaddr;
	72
	73	authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
	74	if (!authsocket)
	75	return -1;
	76
	77	sunaddr.sun_family = AF_UNIX;
	78	strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
	79
	80	sock = socket(AF_UNIX, SOCK_STREAM, 0);
	81	if (sock < 0)
	82	return -1;
	83
	84	/* close on exec */
	85	if (fcntl(sock, F_SETFD, 1) == -1) {
	86	close(sock);
	87	return -1;
	88	}
	89	if (connect(sock, (struct sockaddr *) &sunaddr, sizeof sunaddr) < 0) {
	90	close(sock);
	91	return -1;
	92	}
	93	return sock;
	94	}
	95
	96	static int
	97	ssh_request_reply(AuthenticationConnection auth, Buffer request, Buffer *reply)
	98	{
	99	int l, len;
	100	char buf[1024];
	101
	102	/* Get the length of the message, and format it in the buffer. */
	103	len = buffer_len(request);
	104	PUT_32BIT(buf, len);
	105
	106	/* Send the length and then the packet to the agent. */
	107	if (atomicio(write, auth->fd, buf, 4) != 4 \|\|
	108	atomicio(write, auth->fd, buffer_ptr(request),
	109	buffer_len(request)) != buffer_len(request)) {
	110	error("Error writing to authentication socket.");
	111	return 0;
	112	}
	113	/*
	114	* Wait for response from the agent. First read the length of the
	115	* response packet.
	116	*/
	117	len = 4;
	118	while (len > 0) {
	119	l = read(auth->fd, buf + 4 - len, len);
	120	if (l == -1 && (errno == EAGAIN \|\| errno == EINTR))
	121	continue;
	122	if (l <= 0) {
	123	error("Error reading response length from authentication socket.");
	124	return 0;
	125	}
	126	len -= l;
127	}
128
129	/* Extract the length, and check it for sanity. */
130	len = GET_32BIT(buf);
131	if (len > 256 * 1024)
132	fatal("Authentication response too long: %d", len);
133
134	/* Read the rest of the response in to the buffer. */
135	buffer_clear(reply);
136	while (len > 0) {
137	l = len;
138	if (l > sizeof(buf))
139	l = sizeof(buf);
140	l = read(auth->fd, buf, l);
141	if (l == -1 && (errno == EAGAIN \|\| errno == EINTR))
142	continue;
143	if (l <= 0) {
144	error("Error reading response from authentication socket.");
145	return 0;
146	}
147	buffer_append(reply, (char *) buf, l);
148	len -= l;
149	}
150	return 1;
151	}
152
153	/*
154	* Closes the agent socket if it should be closed (depends on how it was
155	* obtained). The argument must have been returned by
156	* ssh_get_authentication_socket().
157	*/
158
159	void
160	ssh_close_authentication_socket(int sock)
161	{
162	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
163	close(sock);
164	}
165
166	/*
167	* Opens and connects a private socket for communication with the
168	* authentication agent. Returns the file descriptor (which must be
169	* shut down and closed by the caller when no longer needed).
170	* Returns NULL if an error occurred and the connection could not be
171	* opened.
172	*/
173
174	AuthenticationConnection *
175	ssh_get_authentication_connection(void)
176	{
177	AuthenticationConnection *auth;
178	int sock;
179
180	sock = ssh_get_authentication_socket();
181
182	/*
183	* Fail if we couldn't obtain a connection. This happens if we
184	* exited due to a timeout.
185	*/
186	if (sock < 0)
187	return NULL;
188
189	auth = xmalloc(sizeof(*auth));
190	auth->fd = sock;
191	buffer_init(&auth->identities);
192	auth->howmany = 0;
193
194	return auth;
195	}
196
197	/*
198	* Closes the connection to the authentication agent and frees any associated
199	* memory.
200	*/
201
202	void
203	ssh_close_authentication_connection(AuthenticationConnection *auth)
204	{
205	buffer_free(&auth->identities);
206	close(auth->fd);
207	xfree(auth);
208	}
209
f5799ae1	210	/* Lock/unlock agent */
	211	int
	212	ssh_lock_agent(AuthenticationConnection auth, int lock, const char password)
	213	{
	214	int type;
	215	Buffer msg;
	216
	217	buffer_init(&msg);
	218	buffer_put_char(&msg, lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK);
	219	buffer_put_cstring(&msg, password);
	220
	221	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	222	buffer_free(&msg);
	223	return 0;
	224	}
	225	type = buffer_get_char(&msg);
	226	buffer_free(&msg);
	227	return decode_reply(type);
	228	}
	229
3c0ef626	230	/*
	231	* Returns the first authentication identity held by the agent.
	232	*/
	233
	234	int
	235	ssh_get_num_identities(AuthenticationConnection *auth, int version)
	236	{
	237	int type, code1 = 0, code2 = 0;
	238	Buffer request;
	239
e9a17296	240	switch (version) {
3c0ef626	241	case 1:
	242	code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
	243	code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
	244	break;
	245	case 2:
	246	code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
	247	code2 = SSH2_AGENT_IDENTITIES_ANSWER;
	248	break;
	249	default:
	250	return 0;
	251	}
	252
	253	/*
	254	* Send a message to the agent requesting for a list of the
	255	* identities it can represent.
	256	*/
	257	buffer_init(&request);
	258	buffer_put_char(&request, code1);
	259
	260	buffer_clear(&auth->identities);
	261	if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
	262	buffer_free(&request);
	263	return 0;
	264	}
	265	buffer_free(&request);
	266
	267	/* Get message type, and verify that we got a proper answer. */
	268	type = buffer_get_char(&auth->identities);
	269	if (agent_failed(type)) {
	270	return 0;
	271	} else if (type != code2) {
	272	fatal("Bad authentication reply message type: %d", type);
	273	}
	274
	275	/* Get the number of entries in the response and check it for sanity. */
	276	auth->howmany = buffer_get_int(&auth->identities);
	277	if (auth->howmany > 1024)
	278	fatal("Too many identities in authentication reply: %d",
	279	auth->howmany);
	280
	281	return auth->howmany;
	282	}
	283
	284	Key *
	285	ssh_get_first_identity(AuthenticationConnection auth, char *comment, int version)
	286	{
	287	/* get number of identities and return the first entry (if any). */
	288	if (ssh_get_num_identities(auth, version) > 0)
	289	return ssh_get_next_identity(auth, comment, version);
	290	return NULL;
	291	}
	292
	293	Key *
	294	ssh_get_next_identity(AuthenticationConnection auth, char *comment, int version)
	295	{
	296	u_int bits;
	297	u_char *blob;
	298	u_int blen;
	299	Key *key = NULL;
	300
	301	/* Return failure if no more entries. */
	302	if (auth->howmany <= 0)
	303	return NULL;
	304
305	/*
306	* Get the next entry from the packet. These will abort with a fatal
307	* error if the packet is too short or contains corrupt data.
308	*/
e9a17296	309	switch (version) {
3c0ef626	310	case 1:
	311	key = key_new(KEY_RSA1);
	312	bits = buffer_get_int(&auth->identities);
	313	buffer_get_bignum(&auth->identities, key->rsa->e);
	314	buffer_get_bignum(&auth->identities, key->rsa->n);
	315	*comment = buffer_get_string(&auth->identities, NULL);
	316	if (bits != BN_num_bits(key->rsa->n))
	317	log("Warning: identity keysize mismatch: actual %d, announced %u",
	318	BN_num_bits(key->rsa->n), bits);
	319	break;
	320	case 2:
	321	blob = buffer_get_string(&auth->identities, &blen);
	322	*comment = buffer_get_string(&auth->identities, NULL);
	323	key = key_from_blob(blob, blen);
	324	xfree(blob);
	325	break;
	326	default:
	327	return NULL;
	328	break;
	329	}
	330	/* Decrement the number of remaining entries. */
	331	auth->howmany--;
	332	return key;
	333	}
	334
	335	/*
	336	* Generates a random challenge, sends it to the agent, and waits for
	337	* response from the agent. Returns true (non-zero) if the agent gave the
	338	* correct answer, zero otherwise. Response type selects the style of
	339	* response desired, with 0 corresponding to protocol version 1.0 (no longer
	340	* supported) and 1 corresponding to protocol version 1.1.
	341	*/
	342
	343	int
	344	ssh_decrypt_challenge(AuthenticationConnection *auth,
	345	Key* key, BIGNUM *challenge,
	346	u_char session_id[16],
	347	u_int response_type,
	348	u_char response[16])
	349	{
	350	Buffer buffer;
	351	int success = 0;
	352	int i;
	353	int type;
	354
	355	if (key->type != KEY_RSA1)
	356	return 0;
	357	if (response_type == 0) {
	358	log("Compatibility with ssh protocol version 1.0 no longer supported.");
	359	return 0;
	360	}
	361	buffer_init(&buffer);
	362	buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
	363	buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
	364	buffer_put_bignum(&buffer, key->rsa->e);
	365	buffer_put_bignum(&buffer, key->rsa->n);
	366	buffer_put_bignum(&buffer, challenge);
e9a17296	367	buffer_append(&buffer, session_id, 16);
3c0ef626	368	buffer_put_int(&buffer, response_type);
	369
	370	if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
	371	buffer_free(&buffer);
	372	return 0;
	373	}
	374	type = buffer_get_char(&buffer);
	375
	376	if (agent_failed(type)) {
	377	log("Agent admitted failure to authenticate using the key.");
	378	} else if (type != SSH_AGENT_RSA_RESPONSE) {
	379	fatal("Bad authentication response: %d", type);
	380	} else {
	381	success = 1;
	382	/*
	383	* Get the response from the packet. This will abort with a
	384	* fatal error if the packet is corrupt.
	385	*/
	386	for (i = 0; i < 16; i++)
	387	response[i] = buffer_get_char(&buffer);
	388	}
	389	buffer_free(&buffer);
	390	return success;
	391	}
	392
	393	/* ask agent to sign data, returns -1 on error, 0 on success */
	394	int
	395	ssh_agent_sign(AuthenticationConnection *auth,
	396	Key *key,
e9a17296	397	u_char *sigp, u_int lenp,
e9a17296	398	u_char *data, u_int datalen)
3c0ef626	399	{
	400	extern int datafellows;
	401	Buffer msg;
	402	u_char *blob;
	403	u_int blen;
	404	int type, flags = 0;
	405	int ret = -1;
	406
	407	if (key_to_blob(key, &blob, &blen) == 0)
	408	return -1;
	409
	410	if (datafellows & SSH_BUG_SIGBLOB)
	411	flags = SSH_AGENT_OLD_SIGNATURE;
	412
	413	buffer_init(&msg);
	414	buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
	415	buffer_put_string(&msg, blob, blen);
	416	buffer_put_string(&msg, data, datalen);
	417	buffer_put_int(&msg, flags);
	418	xfree(blob);
	419
	420	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	421	buffer_free(&msg);
	422	return -1;
	423	}
	424	type = buffer_get_char(&msg);
	425	if (agent_failed(type)) {
	426	log("Agent admitted failure to sign using the key.");
	427	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
	428	fatal("Bad authentication response: %d", type);
	429	} else {
	430	ret = 0;
	431	*sigp = buffer_get_string(&msg, lenp);
	432	}
	433	buffer_free(&msg);
	434	return ret;
	435	}
	436
	437	/* Encode key for a message to the agent. */
	438
	439	static void
	440	ssh_encode_identity_rsa1(Buffer b, RSA key, const char *comment)
	441	{
3c0ef626	442	buffer_put_int(b, BN_num_bits(key->n));
	443	buffer_put_bignum(b, key->n);
	444	buffer_put_bignum(b, key->e);
	445	buffer_put_bignum(b, key->d);
	446	/* To keep within the protocol: p < q for ssh. in SSL p > q */
	447	buffer_put_bignum(b, key->iqmp); /* ssh key->u */
	448	buffer_put_bignum(b, key->q); /* ssh key->p, SSL key->q */
	449	buffer_put_bignum(b, key->p); /* ssh key->q, SSL key->p */
	450	buffer_put_cstring(b, comment);
	451	}
	452
	453	static void
	454	ssh_encode_identity_ssh2(Buffer b, Key key, const char *comment)
	455	{
3c0ef626	456	buffer_put_cstring(b, key_ssh_name(key));
e9a17296	457	switch (key->type) {
3c0ef626	458	case KEY_RSA:
	459	buffer_put_bignum2(b, key->rsa->n);
	460	buffer_put_bignum2(b, key->rsa->e);
	461	buffer_put_bignum2(b, key->rsa->d);
	462	buffer_put_bignum2(b, key->rsa->iqmp);
	463	buffer_put_bignum2(b, key->rsa->p);
	464	buffer_put_bignum2(b, key->rsa->q);
	465	break;
	466	case KEY_DSA:
	467	buffer_put_bignum2(b, key->dsa->p);
	468	buffer_put_bignum2(b, key->dsa->q);
	469	buffer_put_bignum2(b, key->dsa->g);
	470	buffer_put_bignum2(b, key->dsa->pub_key);
	471	buffer_put_bignum2(b, key->dsa->priv_key);
	472	break;
	473	}
	474	buffer_put_cstring(b, comment);
	475	}
	476
	477	/*
	478	* Adds an identity to the authentication server. This call is not meant to
	479	* be used by normal applications.
	480	*/
	481
	482	int
f5799ae1	483	ssh_add_identity_constrained(AuthenticationConnection auth, Key key,
f5799ae1	484	const char *comment, u_int life)
3c0ef626	485	{
3c0ef626	486	Buffer msg;
f5799ae1	487	int type, constrained = (life != 0);
3c0ef626	488
	489	buffer_init(&msg);
	490
	491	switch (key->type) {
	492	case KEY_RSA1:
f5799ae1	493	type = constrained ?
	494	SSH_AGENTC_ADD_RSA_ID_CONSTRAINED :
	495	SSH_AGENTC_ADD_RSA_IDENTITY;
	496	buffer_put_char(&msg, type);
3c0ef626	497	ssh_encode_identity_rsa1(&msg, key->rsa, comment);
	498	break;
	499	case KEY_RSA:
	500	case KEY_DSA:
f5799ae1	501	type = constrained ?
	502	SSH2_AGENTC_ADD_ID_CONSTRAINED :
	503	SSH2_AGENTC_ADD_IDENTITY;
	504	buffer_put_char(&msg, type);
3c0ef626	505	ssh_encode_identity_ssh2(&msg, key, comment);
	506	break;
	507	default:
	508	buffer_free(&msg);
	509	return 0;
	510	break;
	511	}
f5799ae1	512	if (constrained) {
	513	if (life != 0) {
	514	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
	515	buffer_put_int(&msg, life);
	516	}
	517	}
3c0ef626	518	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	519	buffer_free(&msg);
	520	return 0;
	521	}
	522	type = buffer_get_char(&msg);
	523	buffer_free(&msg);
	524	return decode_reply(type);
	525	}
	526
f5799ae1	527	int
	528	ssh_add_identity(AuthenticationConnection auth, Key key, const char *comment)
	529	{
	530	return ssh_add_identity_constrained(auth, key, comment, 0);
	531	}
	532
3c0ef626	533	/*
	534	* Removes an identity from the authentication server. This call is not
	535	* meant to be used by normal applications.
	536	*/
	537
	538	int
	539	ssh_remove_identity(AuthenticationConnection auth, Key key)
	540	{
	541	Buffer msg;
	542	int type;
	543	u_char *blob;
	544	u_int blen;
	545
	546	buffer_init(&msg);
	547
	548	if (key->type == KEY_RSA1) {
	549	buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
	550	buffer_put_int(&msg, BN_num_bits(key->rsa->n));
	551	buffer_put_bignum(&msg, key->rsa->e);
	552	buffer_put_bignum(&msg, key->rsa->n);
	553	} else if (key->type == KEY_DSA \|\| key->type == KEY_RSA) {
	554	key_to_blob(key, &blob, &blen);
	555	buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
	556	buffer_put_string(&msg, blob, blen);
	557	xfree(blob);
	558	} else {
	559	buffer_free(&msg);
	560	return 0;
	561	}
	562	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	563	buffer_free(&msg);
	564	return 0;
	565	}
	566	type = buffer_get_char(&msg);
	567	buffer_free(&msg);
	568	return decode_reply(type);
	569	}
	570
	571	int
700318f3	572	ssh_update_card(AuthenticationConnection auth, int add, const char reader_id, const char *pin)
3c0ef626	573	{
	574	Buffer msg;
	575	int type;
	576
	577	buffer_init(&msg);
	578	buffer_put_char(&msg, add ? SSH_AGENTC_ADD_SMARTCARD_KEY :
	579	SSH_AGENTC_REMOVE_SMARTCARD_KEY);
	580	buffer_put_cstring(&msg, reader_id);
700318f3	581	buffer_put_cstring(&msg, pin);
3c0ef626	582	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	583	buffer_free(&msg);
	584	return 0;
	585	}
	586	type = buffer_get_char(&msg);
	587	buffer_free(&msg);
	588	return decode_reply(type);
	589	}
	590
	591	/*
	592	* Removes all identities from the agent. This call is not meant to be used
	593	* by normal applications.
	594	*/
	595
	596	int
	597	ssh_remove_all_identities(AuthenticationConnection *auth, int version)
	598	{
	599	Buffer msg;
	600	int type;
	601	int code = (version==1) ?
	602	SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
	603	SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
	604
	605	buffer_init(&msg);
	606	buffer_put_char(&msg, code);
	607
	608	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	609	buffer_free(&msg);
	610	return 0;
	611	}
	612	type = buffer_get_char(&msg);
	613	buffer_free(&msg);
	614	return decode_reply(type);
	615	}
	616
	617	int
	618	decode_reply(int type)
	619	{
	620	switch (type) {
	621	case SSH_AGENT_FAILURE:
	622	case SSH_COM_AGENT2_FAILURE:
	623	case SSH2_AGENT_FAILURE:
	624	log("SSH_AGENT_FAILURE");
	625	return 0;
	626	case SSH_AGENT_SUCCESS:
	627	return 1;
	628	default:
	629	fatal("Bad response from authentication agent: %d", type);
	630	}
	631	/* NOTREACHED */
	632	return 0;
	633	}