[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 1.44 2001/08/07 10:37:46 markus 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, len;
	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));
	len = SUN_LEN(&sunaddr)+1;
#ifdef HAVE_SUN_LEN_IN_SOCKADDR_UN
	sunaddr.sun_len = len;
#endif /* HAVE_SUN_LEN_IN_SOCKADDR_UN */

	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, len) < 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);
}

/*
 * 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, (char *) 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, int *lenp,
    u_char *data, 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_clear(b);
	buffer_put_char(b, SSH_AGENTC_ADD_RSA_IDENTITY);
	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_clear(b);
	buffer_put_char(b, SSH2_AGENTC_ADD_IDENTITY);
	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(AuthenticationConnection *auth, Key *key, const char *comment)
{
	Buffer msg;
	int type;

	buffer_init(&msg);

	switch (key->type) {
	case KEY_RSA1:
		ssh_encode_identity_rsa1(&msg, key->rsa, comment);
		break;
	case KEY_RSA:
	case KEY_DSA:
		ssh_encode_identity_ssh2(&msg, key, comment);
		break;
	default:
		buffer_free(&msg);
		return 0;
		break;
	}
	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 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)
{
	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);
	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
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"
65e683bd	38	RCSID("$OpenBSD: authfd.c,v 1.44 2001/08/07 10:37:46 markus 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
089fbbd2	56	/* helper */
c345cf9d	57	int decode_reply(int type);
089fbbd2	58
94ec8c6b	59	/* macro to check for "agent failure" message */
94ec8c6b	60	#define agent_failed(x) \
65e683bd	61	((x == SSH_AGENT_FAILURE) \|\| (x == SSH_COM_AGENT2_FAILURE) \|\| \
65e683bd	62	(x == SSH2_AGENT_FAILURE))
94ec8c6b	63
8efc0c15	64	/* Returns the number of the authentication fd, or -1 if there is none. */
	65
	66	int
1e3b8b07	67	ssh_get_authentication_socket(void)
8efc0c15	68	{
5260325f	69	const char *authsocket;
c345cf9d	70	int sock, len;
5260325f	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));
c345cf9d	79	len = SUN_LEN(&sunaddr)+1;
c3f7d267	80	#ifdef HAVE_SUN_LEN_IN_SOCKADDR_UN
c3f7d267	81	sunaddr.sun_len = len;
c345cf9d	82	#endif /* HAVE_SUN_LEN_IN_SOCKADDR_UN */
5260325f	83
	84	sock = socket(AF_UNIX, SOCK_STREAM, 0);
	85	if (sock < 0)
	86	return -1;
	87
	88	/* close on exec */
	89	if (fcntl(sock, F_SETFD, 1) == -1) {
	90	close(sock);
	91	return -1;
	92	}
c345cf9d	93	if (connect(sock, (struct sockaddr *) & sunaddr, len) < 0) {
5260325f	94	close(sock);
	95	return -1;
	96	}
	97	return sock;
8efc0c15	98	}
8efc0c15	99
396c147e	100	static int
2e73a022	101	ssh_request_reply(AuthenticationConnection auth, Buffer request, Buffer *reply)
c345cf9d	102	{
	103	int l, len;
	104	char buf[1024];
	105
	106	/* Get the length of the message, and format it in the buffer. */
	107	len = buffer_len(request);
	108	PUT_32BIT(buf, len);
	109
	110	/* Send the length and then the packet to the agent. */
	111	if (atomicio(write, auth->fd, buf, 4) != 4 \|\|
	112	atomicio(write, auth->fd, buffer_ptr(request),
	113	buffer_len(request)) != buffer_len(request)) {
	114	error("Error writing to authentication socket.");
	115	return 0;
	116	}
	117	/*
	118	* Wait for response from the agent. First read the length of the
	119	* response packet.
	120	*/
	121	len = 4;
	122	while (len > 0) {
	123	l = read(auth->fd, buf + 4 - len, len);
bbc62e59	124	if (l == -1 && (errno == EAGAIN \|\| errno == EINTR))
cd332296	125	continue;
c345cf9d	126	if (l <= 0) {
	127	error("Error reading response length from authentication socket.");
	128	return 0;
	129	}
	130	len -= l;
	131	}
	132
	133	/* Extract the length, and check it for sanity. */
	134	len = GET_32BIT(buf);
	135	if (len > 256 * 1024)
	136	fatal("Authentication response too long: %d", len);
	137
	138	/* Read the rest of the response in to the buffer. */
	139	buffer_clear(reply);
	140	while (len > 0) {
	141	l = len;
	142	if (l > sizeof(buf))
	143	l = sizeof(buf);
	144	l = read(auth->fd, buf, l);
bbc62e59	145	if (l == -1 && (errno == EAGAIN \|\| errno == EINTR))
cd332296	146	continue;
c345cf9d	147	if (l <= 0) {
	148	error("Error reading response from authentication socket.");
	149	return 0;
	150	}
	151	buffer_append(reply, (char *) buf, l);
	152	len -= l;
	153	}
	154	return 1;
	155	}
	156
aa3378df	157	/*
	158	* Closes the agent socket if it should be closed (depends on how it was
	159	* obtained). The argument must have been returned by
	160	* ssh_get_authentication_socket().
	161	*/
8efc0c15	162
6ae2364d	163	void
5260325f	164	ssh_close_authentication_socket(int sock)
8efc0c15	165	{
5260325f	166	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
5260325f	167	close(sock);
8efc0c15	168	}
8efc0c15	169
aa3378df	170	/*
	171	* Opens and connects a private socket for communication with the
	172	* authentication agent. Returns the file descriptor (which must be
	173	* shut down and closed by the caller when no longer needed).
	174	* Returns NULL if an error occurred and the connection could not be
	175	* opened.
	176	*/
8efc0c15	177
5260325f	178	AuthenticationConnection *
1e3b8b07	179	ssh_get_authentication_connection(void)
8efc0c15	180	{
5260325f	181	AuthenticationConnection *auth;
	182	int sock;
	183
	184	sock = ssh_get_authentication_socket();
	185
aa3378df	186	/*
	187	* Fail if we couldn't obtain a connection. This happens if we
	188	* exited due to a timeout.
	189	*/
5260325f	190	if (sock < 0)
	191	return NULL;
	192
5260325f	193	auth = xmalloc(sizeof(*auth));
5260325f	194	auth->fd = sock;
5260325f	195	buffer_init(&auth->identities);
	196	auth->howmany = 0;
	197
	198	return auth;
8efc0c15	199	}
8efc0c15	200
aa3378df	201	/*
	202	* Closes the connection to the authentication agent and frees any associated
	203	* memory.
	204	*/
8efc0c15	205
6ae2364d	206	void
2e73a022	207	ssh_close_authentication_connection(AuthenticationConnection *auth)
8efc0c15	208	{
2e73a022	209	buffer_free(&auth->identities);
	210	close(auth->fd);
	211	xfree(auth);
8efc0c15	212	}
8efc0c15	213
aa3378df	214	/*
aa3378df	215	* Returns the first authentication identity held by the agent.
aa3378df	216	*/
8efc0c15	217
fa08c86b	218	int
fa08c86b	219	ssh_get_num_identities(AuthenticationConnection *auth, int version)
8efc0c15	220	{
2e73a022	221	int type, code1 = 0, code2 = 0;
c345cf9d	222	Buffer request;
2e73a022	223
	224	switch(version){
	225	case 1:
	226	code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
	227	code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
	228	break;
	229	case 2:
	230	code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
	231	code2 = SSH2_AGENT_IDENTITIES_ANSWER;
	232	break;
	233	default:
fa08c86b	234	return 0;
2e73a022	235	}
5260325f	236
aa3378df	237	/*
	238	* Send a message to the agent requesting for a list of the
	239	* identities it can represent.
	240	*/
c345cf9d	241	buffer_init(&request);
2e73a022	242	buffer_put_char(&request, code1);
5260325f	243
5260325f	244	buffer_clear(&auth->identities);
c345cf9d	245	if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
c345cf9d	246	buffer_free(&request);
fa08c86b	247	return 0;
8efc0c15	248	}
c345cf9d	249	buffer_free(&request);
5260325f	250
5260325f	251	/* Get message type, and verify that we got a proper answer. */
c345cf9d	252	type = buffer_get_char(&auth->identities);
94ec8c6b	253	if (agent_failed(type)) {
fa08c86b	254	return 0;
2e73a022	255	} else if (type != code2) {
c345cf9d	256	fatal("Bad authentication reply message type: %d", type);
2e73a022	257	}
5260325f	258
	259	/* Get the number of entries in the response and check it for sanity. */
	260	auth->howmany = buffer_get_int(&auth->identities);
	261	if (auth->howmany > 1024)
54b974dc	262	fatal("Too many identities in authentication reply: %d",
c345cf9d	263	auth->howmany);
5260325f	264
fa08c86b	265	return auth->howmany;
	266	}
	267
	268	Key *
	269	ssh_get_first_identity(AuthenticationConnection auth, char *comment, int version)
	270	{
	271	/* get number of identities and return the first entry (if any). */
	272	if (ssh_get_num_identities(auth, version) > 0)
	273	return ssh_get_next_identity(auth, comment, version);
	274	return NULL;
8efc0c15	275	}
8efc0c15	276
2e73a022	277	Key *
2e73a022	278	ssh_get_next_identity(AuthenticationConnection auth, char *comment, int version)
8efc0c15	279	{
1e3b8b07	280	u_int bits;
	281	u_char *blob;
	282	u_int blen;
2e73a022	283	Key *key = NULL;
4d195447	284
5260325f	285	/* Return failure if no more entries. */
5260325f	286	if (auth->howmany <= 0)
2e73a022	287	return NULL;
8efc0c15	288
aa3378df	289	/*
	290	* Get the next entry from the packet. These will abort with a fatal
	291	* error if the packet is too short or contains corrupt data.
	292	*/
2e73a022	293	switch(version){
2e73a022	294	case 1:
fa08c86b	295	key = key_new(KEY_RSA1);
2e73a022	296	bits = buffer_get_int(&auth->identities);
	297	buffer_get_bignum(&auth->identities, key->rsa->e);
	298	buffer_get_bignum(&auth->identities, key->rsa->n);
	299	*comment = buffer_get_string(&auth->identities, NULL);
	300	if (bits != BN_num_bits(key->rsa->n))
	301	log("Warning: identity keysize mismatch: actual %d, announced %u",
	302	BN_num_bits(key->rsa->n), bits);
	303	break;
	304	case 2:
	305	blob = buffer_get_string(&auth->identities, &blen);
	306	*comment = buffer_get_string(&auth->identities, NULL);
fa08c86b	307	key = key_from_blob(blob, blen);
2e73a022	308	xfree(blob);
	309	break;
	310	default:
	311	return NULL;
	312	break;
	313	}
5260325f	314	/* Decrement the number of remaining entries. */
5260325f	315	auth->howmany--;
2e73a022	316	return key;
8efc0c15	317	}
8efc0c15	318
aa3378df	319	/*
	320	* Generates a random challenge, sends it to the agent, and waits for
	321	* response from the agent. Returns true (non-zero) if the agent gave the
	322	* correct answer, zero otherwise. Response type selects the style of
	323	* response desired, with 0 corresponding to protocol version 1.0 (no longer
	324	* supported) and 1 corresponding to protocol version 1.1.
	325	*/
8efc0c15	326
	327	int
	328	ssh_decrypt_challenge(AuthenticationConnection *auth,
2e73a022	329	Key* key, BIGNUM *challenge,
1e3b8b07	330	u_char session_id[16],
	331	u_int response_type,
	332	u_char response[16])
8efc0c15	333	{
5260325f	334	Buffer buffer;
c345cf9d	335	int success = 0;
	336	int i;
	337	int type;
5260325f	338
fa08c86b	339	if (key->type != KEY_RSA1)
2e73a022	340	return 0;
	341	if (response_type == 0) {
	342	log("Compatibility with ssh protocol version 1.0 no longer supported.");
	343	return 0;
	344	}
5260325f	345	buffer_init(&buffer);
c345cf9d	346	buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
2e73a022	347	buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
	348	buffer_put_bignum(&buffer, key->rsa->e);
	349	buffer_put_bignum(&buffer, key->rsa->n);
5260325f	350	buffer_put_bignum(&buffer, challenge);
	351	buffer_append(&buffer, (char *) session_id, 16);
	352	buffer_put_int(&buffer, response_type);
	353
c345cf9d	354	if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
5260325f	355	buffer_free(&buffer);
	356	return 0;
	357	}
c345cf9d	358	type = buffer_get_char(&buffer);
5260325f	359
94ec8c6b	360	if (agent_failed(type)) {
5260325f	361	log("Agent admitted failure to authenticate using the key.");
c345cf9d	362	} else if (type != SSH_AGENT_RSA_RESPONSE) {
	363	fatal("Bad authentication response: %d", type);
	364	} else {
	365	success = 1;
	366	/*
	367	* Get the response from the packet. This will abort with a
	368	* fatal error if the packet is corrupt.
	369	*/
	370	for (i = 0; i < 16; i++)
	371	response[i] = buffer_get_char(&buffer);
8efc0c15	372	}
5260325f	373	buffer_free(&buffer);
c345cf9d	374	return success;
5260325f	375	}
8efc0c15	376
2e73a022	377	/* ask agent to sign data, returns -1 on error, 0 on success */
	378	int
	379	ssh_agent_sign(AuthenticationConnection *auth,
	380	Key *key,
1e3b8b07	381	u_char *sigp, int lenp,
1e3b8b07	382	u_char *data, int datalen)
2e73a022	383	{
188adeb2	384	extern int datafellows;
2e73a022	385	Buffer msg;
1e3b8b07	386	u_char *blob;
1e3b8b07	387	u_int blen;
188adeb2	388	int type, flags = 0;
2e73a022	389	int ret = -1;
2e73a022	390
fa08c86b	391	if (key_to_blob(key, &blob, &blen) == 0)
2e73a022	392	return -1;
2e73a022	393
188adeb2	394	if (datafellows & SSH_BUG_SIGBLOB)
	395	flags = SSH_AGENT_OLD_SIGNATURE;
	396
2e73a022	397	buffer_init(&msg);
	398	buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
	399	buffer_put_string(&msg, blob, blen);
	400	buffer_put_string(&msg, data, datalen);
188adeb2	401	buffer_put_int(&msg, flags);
2e73a022	402	xfree(blob);
	403
	404	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	405	buffer_free(&msg);
	406	return -1;
	407	}
	408	type = buffer_get_char(&msg);
94ec8c6b	409	if (agent_failed(type)) {
2e73a022	410	log("Agent admitted failure to sign using the key.");
	411	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
	412	fatal("Bad authentication response: %d", type);
	413	} else {
	414	ret = 0;
	415	*sigp = buffer_get_string(&msg, lenp);
	416	}
	417	buffer_free(&msg);
	418	return ret;
	419	}
	420
4c8722d9	421	/* Encode key for a message to the agent. */
4c8722d9	422
396c147e	423	static void
fa08c86b	424	ssh_encode_identity_rsa1(Buffer b, RSA key, const char *comment)
4c8722d9	425	{
	426	buffer_clear(b);
	427	buffer_put_char(b, SSH_AGENTC_ADD_RSA_IDENTITY);
	428	buffer_put_int(b, BN_num_bits(key->n));
	429	buffer_put_bignum(b, key->n);
	430	buffer_put_bignum(b, key->e);
	431	buffer_put_bignum(b, key->d);
	432	/* To keep within the protocol: p < q for ssh. in SSL p > q */
	433	buffer_put_bignum(b, key->iqmp); /* ssh key->u */
	434	buffer_put_bignum(b, key->q); /* ssh key->p, SSL key->q */
	435	buffer_put_bignum(b, key->p); /* ssh key->q, SSL key->p */
449c5ba5	436	buffer_put_cstring(b, comment);
4c8722d9	437	}
4c8722d9	438
396c147e	439	static void
fa08c86b	440	ssh_encode_identity_ssh2(Buffer b, Key key, const char *comment)
4c8722d9	441	{
	442	buffer_clear(b);
	443	buffer_put_char(b, SSH2_AGENTC_ADD_IDENTITY);
fa08c86b	444	buffer_put_cstring(b, key_ssh_name(key));
	445	switch(key->type){
	446	case KEY_RSA:
	447	buffer_put_bignum2(b, key->rsa->n);
	448	buffer_put_bignum2(b, key->rsa->e);
	449	buffer_put_bignum2(b, key->rsa->d);
	450	buffer_put_bignum2(b, key->rsa->iqmp);
	451	buffer_put_bignum2(b, key->rsa->p);
	452	buffer_put_bignum2(b, key->rsa->q);
	453	break;
	454	case KEY_DSA:
	455	buffer_put_bignum2(b, key->dsa->p);
	456	buffer_put_bignum2(b, key->dsa->q);
	457	buffer_put_bignum2(b, key->dsa->g);
	458	buffer_put_bignum2(b, key->dsa->pub_key);
	459	buffer_put_bignum2(b, key->dsa->priv_key);
	460	break;
	461	}
	462	buffer_put_cstring(b, comment);
4c8722d9	463	}
4c8722d9	464
aa3378df	465	/*
	466	* Adds an identity to the authentication server. This call is not meant to
	467	* be used by normal applications.
	468	*/
8efc0c15	469
6ae2364d	470	int
4c8722d9	471	ssh_add_identity(AuthenticationConnection auth, Key key, const char *comment)
8efc0c15	472	{
2e73a022	473	Buffer msg;
c345cf9d	474	int type;
5260325f	475
2e73a022	476	buffer_init(&msg);
4c8722d9	477
4c8722d9	478	switch (key->type) {
fa08c86b	479	case KEY_RSA1:
fa08c86b	480	ssh_encode_identity_rsa1(&msg, key->rsa, comment);
4c8722d9	481	break;
fa08c86b	482	case KEY_RSA:
4c8722d9	483	case KEY_DSA:
fa08c86b	484	ssh_encode_identity_ssh2(&msg, key, comment);
4c8722d9	485	break;
4c8722d9	486	default:
2e73a022	487	buffer_free(&msg);
4c8722d9	488	return 0;
	489	break;
	490	}
2e73a022	491	if (ssh_request_reply(auth, &msg, &msg) == 0) {
2e73a022	492	buffer_free(&msg);
5260325f	493	return 0;
5260325f	494	}
2e73a022	495	type = buffer_get_char(&msg);
2e73a022	496	buffer_free(&msg);
c345cf9d	497	return decode_reply(type);
5260325f	498	}
5260325f	499
aa3378df	500	/*
	501	* Removes an identity from the authentication server. This call is not
	502	* meant to be used by normal applications.
	503	*/
8efc0c15	504
6ae2364d	505	int
2e73a022	506	ssh_remove_identity(AuthenticationConnection auth, Key key)
8efc0c15	507	{
2e73a022	508	Buffer msg;
c345cf9d	509	int type;
1e3b8b07	510	u_char *blob;
1e3b8b07	511	u_int blen;
2e73a022	512
	513	buffer_init(&msg);
	514
fa08c86b	515	if (key->type == KEY_RSA1) {
2e73a022	516	buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
	517	buffer_put_int(&msg, BN_num_bits(key->rsa->n));
	518	buffer_put_bignum(&msg, key->rsa->e);
	519	buffer_put_bignum(&msg, key->rsa->n);
fa08c86b	520	} else if (key->type == KEY_DSA \|\| key->type == KEY_RSA) {
fa08c86b	521	key_to_blob(key, &blob, &blen);
2e73a022	522	buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
	523	buffer_put_string(&msg, blob, blen);
	524	xfree(blob);
	525	} else {
	526	buffer_free(&msg);
5260325f	527	return 0;
5260325f	528	}
2e73a022	529	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	530	buffer_free(&msg);
	531	return 0;
	532	}
	533	type = buffer_get_char(&msg);
	534	buffer_free(&msg);
c345cf9d	535	return decode_reply(type);
5260325f	536	}
5260325f	537
983def13	538	int
9ff6f66f	539	ssh_update_card(AuthenticationConnection auth, int add, const char reader_id)
983def13	540	{
	541	Buffer msg;
	542	int type;
	543
	544	buffer_init(&msg);
	545	buffer_put_char(&msg, add ? SSH_AGENTC_ADD_SMARTCARD_KEY :
	546	SSH_AGENTC_REMOVE_SMARTCARD_KEY);
9ff6f66f	547	buffer_put_cstring(&msg, reader_id);
983def13	548	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	549	buffer_free(&msg);
	550	return 0;
	551	}
	552	type = buffer_get_char(&msg);
	553	buffer_free(&msg);
	554	return decode_reply(type);
	555	}
	556
aa3378df	557	/*
	558	* Removes all identities from the agent. This call is not meant to be used
	559	* by normal applications.
	560	*/
8efc0c15	561
6ae2364d	562	int
2e73a022	563	ssh_remove_all_identities(AuthenticationConnection *auth, int version)
8efc0c15	564	{
2e73a022	565	Buffer msg;
c345cf9d	566	int type;
2e73a022	567	int code = (version==1) ?
	568	SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
	569	SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
5260325f	570
2e73a022	571	buffer_init(&msg);
2e73a022	572	buffer_put_char(&msg, code);
5260325f	573
2e73a022	574	if (ssh_request_reply(auth, &msg, &msg) == 0) {
2e73a022	575	buffer_free(&msg);
5260325f	576	return 0;
5260325f	577	}
2e73a022	578	type = buffer_get_char(&msg);
2e73a022	579	buffer_free(&msg);
c345cf9d	580	return decode_reply(type);
089fbbd2	581	}
089fbbd2	582
2b87da3b	583	int
c345cf9d	584	decode_reply(int type)
089fbbd2	585	{
5260325f	586	switch (type) {
5260325f	587	case SSH_AGENT_FAILURE:
94ec8c6b	588	case SSH_COM_AGENT2_FAILURE:
65e683bd	589	case SSH2_AGENT_FAILURE:
c345cf9d	590	log("SSH_AGENT_FAILURE");
5260325f	591	return 0;
5260325f	592	case SSH_AGENT_SUCCESS:
5260325f	593	return 1;
5260325f	594	default:
089fbbd2	595	fatal("Bad response from authentication agent: %d", type);
8efc0c15	596	}
5260325f	597	/* NOTREACHED */
	598	return 0;
	599	}