[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 1.36 2001/03/01 02:11:25 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))

/* 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;
}

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 <= 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 <= 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\n",
		    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. */

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_string(b, comment, strlen(comment));
}

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);
}

/*
 * 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:
		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"
c3f7d267	38	RCSID("$OpenBSD: authfd.c,v 1.36 2001/03/01 02:11:25 deraadt 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 */
	60	#define agent_failed(x) \
	61	((x == SSH_AGENT_FAILURE) \|\| (x == SSH_COM_AGENT2_FAILURE))
	62
8efc0c15	63	/* Returns the number of the authentication fd, or -1 if there is none. */
	64
	65	int
1e3b8b07	66	ssh_get_authentication_socket(void)
8efc0c15	67	{
5260325f	68	const char *authsocket;
c345cf9d	69	int sock, len;
5260325f	70	struct sockaddr_un sunaddr;
	71
	72	authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
	73	if (!authsocket)
	74	return -1;
	75
	76	sunaddr.sun_family = AF_UNIX;
	77	strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
c345cf9d	78	len = SUN_LEN(&sunaddr)+1;
c3f7d267	79	#ifdef HAVE_SUN_LEN_IN_SOCKADDR_UN
c3f7d267	80	sunaddr.sun_len = len;
c345cf9d	81	#endif /* HAVE_SUN_LEN_IN_SOCKADDR_UN */
5260325f	82
	83	sock = socket(AF_UNIX, SOCK_STREAM, 0);
	84	if (sock < 0)
	85	return -1;
	86
	87	/* close on exec */
	88	if (fcntl(sock, F_SETFD, 1) == -1) {
	89	close(sock);
	90	return -1;
	91	}
c345cf9d	92	if (connect(sock, (struct sockaddr *) & sunaddr, len) < 0) {
5260325f	93	close(sock);
	94	return -1;
	95	}
	96	return sock;
8efc0c15	97	}
8efc0c15	98
c345cf9d	99	int
2e73a022	100	ssh_request_reply(AuthenticationConnection auth, Buffer request, Buffer *reply)
c345cf9d	101	{
	102	int l, len;
	103	char buf[1024];
	104
	105	/* Get the length of the message, and format it in the buffer. */
	106	len = buffer_len(request);
	107	PUT_32BIT(buf, len);
	108
	109	/* Send the length and then the packet to the agent. */
	110	if (atomicio(write, auth->fd, buf, 4) != 4 \|\|
	111	atomicio(write, auth->fd, buffer_ptr(request),
	112	buffer_len(request)) != buffer_len(request)) {
	113	error("Error writing to authentication socket.");
	114	return 0;
	115	}
	116	/*
	117	* Wait for response from the agent. First read the length of the
	118	* response packet.
	119	*/
	120	len = 4;
	121	while (len > 0) {
	122	l = read(auth->fd, buf + 4 - len, len);
	123	if (l <= 0) {
	124	error("Error reading response length from authentication socket.");
	125	return 0;
	126	}
	127	len -= l;
	128	}
	129
	130	/* Extract the length, and check it for sanity. */
	131	len = GET_32BIT(buf);
	132	if (len > 256 * 1024)
	133	fatal("Authentication response too long: %d", len);
	134
	135	/* Read the rest of the response in to the buffer. */
	136	buffer_clear(reply);
	137	while (len > 0) {
	138	l = len;
	139	if (l > sizeof(buf))
	140	l = sizeof(buf);
	141	l = read(auth->fd, buf, l);
	142	if (l <= 0) {
	143	error("Error reading response from authentication socket.");
	144	return 0;
	145	}
	146	buffer_append(reply, (char *) buf, l);
	147	len -= l;
	148	}
	149	return 1;
	150	}
	151
aa3378df	152	/*
	153	* Closes the agent socket if it should be closed (depends on how it was
	154	* obtained). The argument must have been returned by
	155	* ssh_get_authentication_socket().
	156	*/
8efc0c15	157
6ae2364d	158	void
5260325f	159	ssh_close_authentication_socket(int sock)
8efc0c15	160	{
5260325f	161	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
5260325f	162	close(sock);
8efc0c15	163	}
8efc0c15	164
aa3378df	165	/*
	166	* Opens and connects a private socket for communication with the
	167	* authentication agent. Returns the file descriptor (which must be
	168	* shut down and closed by the caller when no longer needed).
	169	* Returns NULL if an error occurred and the connection could not be
	170	* opened.
	171	*/
8efc0c15	172
5260325f	173	AuthenticationConnection *
1e3b8b07	174	ssh_get_authentication_connection(void)
8efc0c15	175	{
5260325f	176	AuthenticationConnection *auth;
	177	int sock;
	178
	179	sock = ssh_get_authentication_socket();
	180
aa3378df	181	/*
	182	* Fail if we couldn't obtain a connection. This happens if we
	183	* exited due to a timeout.
	184	*/
5260325f	185	if (sock < 0)
	186	return NULL;
	187
5260325f	188	auth = xmalloc(sizeof(*auth));
5260325f	189	auth->fd = sock;
5260325f	190	buffer_init(&auth->identities);
	191	auth->howmany = 0;
	192
	193	return auth;
8efc0c15	194	}
8efc0c15	195
aa3378df	196	/*
	197	* Closes the connection to the authentication agent and frees any associated
	198	* memory.
	199	*/
8efc0c15	200
6ae2364d	201	void
2e73a022	202	ssh_close_authentication_connection(AuthenticationConnection *auth)
8efc0c15	203	{
2e73a022	204	buffer_free(&auth->identities);
	205	close(auth->fd);
	206	xfree(auth);
8efc0c15	207	}
8efc0c15	208
aa3378df	209	/*
aa3378df	210	* Returns the first authentication identity held by the agent.
aa3378df	211	*/
8efc0c15	212
fa08c86b	213	int
fa08c86b	214	ssh_get_num_identities(AuthenticationConnection *auth, int version)
8efc0c15	215	{
2e73a022	216	int type, code1 = 0, code2 = 0;
c345cf9d	217	Buffer request;
2e73a022	218
	219	switch(version){
	220	case 1:
	221	code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
	222	code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
	223	break;
	224	case 2:
	225	code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
	226	code2 = SSH2_AGENT_IDENTITIES_ANSWER;
	227	break;
	228	default:
fa08c86b	229	return 0;
2e73a022	230	}
5260325f	231
aa3378df	232	/*
	233	* Send a message to the agent requesting for a list of the
	234	* identities it can represent.
	235	*/
c345cf9d	236	buffer_init(&request);
2e73a022	237	buffer_put_char(&request, code1);
5260325f	238
5260325f	239	buffer_clear(&auth->identities);
c345cf9d	240	if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
c345cf9d	241	buffer_free(&request);
fa08c86b	242	return 0;
8efc0c15	243	}
c345cf9d	244	buffer_free(&request);
5260325f	245
5260325f	246	/* Get message type, and verify that we got a proper answer. */
c345cf9d	247	type = buffer_get_char(&auth->identities);
94ec8c6b	248	if (agent_failed(type)) {
fa08c86b	249	return 0;
2e73a022	250	} else if (type != code2) {
c345cf9d	251	fatal("Bad authentication reply message type: %d", type);
2e73a022	252	}
5260325f	253
	254	/* Get the number of entries in the response and check it for sanity. */
	255	auth->howmany = buffer_get_int(&auth->identities);
	256	if (auth->howmany > 1024)
c345cf9d	257	fatal("Too many identities in authentication reply: %d\n",
c345cf9d	258	auth->howmany);
5260325f	259
fa08c86b	260	return auth->howmany;
	261	}
	262
	263	Key *
	264	ssh_get_first_identity(AuthenticationConnection auth, char *comment, int version)
	265	{
	266	/* get number of identities and return the first entry (if any). */
	267	if (ssh_get_num_identities(auth, version) > 0)
	268	return ssh_get_next_identity(auth, comment, version);
	269	return NULL;
8efc0c15	270	}
8efc0c15	271
2e73a022	272	Key *
2e73a022	273	ssh_get_next_identity(AuthenticationConnection auth, char *comment, int version)
8efc0c15	274	{
1e3b8b07	275	u_int bits;
	276	u_char *blob;
	277	u_int blen;
2e73a022	278	Key *key = NULL;
4d195447	279
5260325f	280	/* Return failure if no more entries. */
5260325f	281	if (auth->howmany <= 0)
2e73a022	282	return NULL;
8efc0c15	283
aa3378df	284	/*
	285	* Get the next entry from the packet. These will abort with a fatal
	286	* error if the packet is too short or contains corrupt data.
	287	*/
2e73a022	288	switch(version){
2e73a022	289	case 1:
fa08c86b	290	key = key_new(KEY_RSA1);
2e73a022	291	bits = buffer_get_int(&auth->identities);
	292	buffer_get_bignum(&auth->identities, key->rsa->e);
	293	buffer_get_bignum(&auth->identities, key->rsa->n);
	294	*comment = buffer_get_string(&auth->identities, NULL);
	295	if (bits != BN_num_bits(key->rsa->n))
	296	log("Warning: identity keysize mismatch: actual %d, announced %u",
	297	BN_num_bits(key->rsa->n), bits);
	298	break;
	299	case 2:
	300	blob = buffer_get_string(&auth->identities, &blen);
	301	*comment = buffer_get_string(&auth->identities, NULL);
fa08c86b	302	key = key_from_blob(blob, blen);
2e73a022	303	xfree(blob);
	304	break;
	305	default:
	306	return NULL;
	307	break;
	308	}
5260325f	309	/* Decrement the number of remaining entries. */
5260325f	310	auth->howmany--;
2e73a022	311	return key;
8efc0c15	312	}
8efc0c15	313
aa3378df	314	/*
	315	* Generates a random challenge, sends it to the agent, and waits for
	316	* response from the agent. Returns true (non-zero) if the agent gave the
	317	* correct answer, zero otherwise. Response type selects the style of
	318	* response desired, with 0 corresponding to protocol version 1.0 (no longer
	319	* supported) and 1 corresponding to protocol version 1.1.
	320	*/
8efc0c15	321
	322	int
	323	ssh_decrypt_challenge(AuthenticationConnection *auth,
2e73a022	324	Key* key, BIGNUM *challenge,
1e3b8b07	325	u_char session_id[16],
	326	u_int response_type,
	327	u_char response[16])
8efc0c15	328	{
5260325f	329	Buffer buffer;
c345cf9d	330	int success = 0;
	331	int i;
	332	int type;
5260325f	333
fa08c86b	334	if (key->type != KEY_RSA1)
2e73a022	335	return 0;
	336	if (response_type == 0) {
	337	log("Compatibility with ssh protocol version 1.0 no longer supported.");
	338	return 0;
	339	}
5260325f	340	buffer_init(&buffer);
c345cf9d	341	buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
2e73a022	342	buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
	343	buffer_put_bignum(&buffer, key->rsa->e);
	344	buffer_put_bignum(&buffer, key->rsa->n);
5260325f	345	buffer_put_bignum(&buffer, challenge);
	346	buffer_append(&buffer, (char *) session_id, 16);
	347	buffer_put_int(&buffer, response_type);
	348
c345cf9d	349	if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
5260325f	350	buffer_free(&buffer);
	351	return 0;
	352	}
c345cf9d	353	type = buffer_get_char(&buffer);
5260325f	354
94ec8c6b	355	if (agent_failed(type)) {
5260325f	356	log("Agent admitted failure to authenticate using the key.");
c345cf9d	357	} else if (type != SSH_AGENT_RSA_RESPONSE) {
	358	fatal("Bad authentication response: %d", type);
	359	} else {
	360	success = 1;
	361	/*
	362	* Get the response from the packet. This will abort with a
	363	* fatal error if the packet is corrupt.
	364	*/
	365	for (i = 0; i < 16; i++)
	366	response[i] = buffer_get_char(&buffer);
8efc0c15	367	}
5260325f	368	buffer_free(&buffer);
c345cf9d	369	return success;
5260325f	370	}
8efc0c15	371
2e73a022	372	/* ask agent to sign data, returns -1 on error, 0 on success */
	373	int
	374	ssh_agent_sign(AuthenticationConnection *auth,
	375	Key *key,
1e3b8b07	376	u_char *sigp, int lenp,
1e3b8b07	377	u_char *data, int datalen)
2e73a022	378	{
188adeb2	379	extern int datafellows;
2e73a022	380	Buffer msg;
1e3b8b07	381	u_char *blob;
1e3b8b07	382	u_int blen;
188adeb2	383	int type, flags = 0;
2e73a022	384	int ret = -1;
2e73a022	385
fa08c86b	386	if (key_to_blob(key, &blob, &blen) == 0)
2e73a022	387	return -1;
2e73a022	388
188adeb2	389	if (datafellows & SSH_BUG_SIGBLOB)
	390	flags = SSH_AGENT_OLD_SIGNATURE;
	391
2e73a022	392	buffer_init(&msg);
	393	buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
	394	buffer_put_string(&msg, blob, blen);
	395	buffer_put_string(&msg, data, datalen);
188adeb2	396	buffer_put_int(&msg, flags);
2e73a022	397	xfree(blob);
	398
	399	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	400	buffer_free(&msg);
	401	return -1;
	402	}
	403	type = buffer_get_char(&msg);
94ec8c6b	404	if (agent_failed(type)) {
2e73a022	405	log("Agent admitted failure to sign using the key.");
	406	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
	407	fatal("Bad authentication response: %d", type);
	408	} else {
	409	ret = 0;
	410	*sigp = buffer_get_string(&msg, lenp);
	411	}
	412	buffer_free(&msg);
	413	return ret;
	414	}
	415
4c8722d9	416	/* Encode key for a message to the agent. */
	417
	418	void
fa08c86b	419	ssh_encode_identity_rsa1(Buffer b, RSA key, const char *comment)
4c8722d9	420	{
	421	buffer_clear(b);
	422	buffer_put_char(b, SSH_AGENTC_ADD_RSA_IDENTITY);
	423	buffer_put_int(b, BN_num_bits(key->n));
	424	buffer_put_bignum(b, key->n);
	425	buffer_put_bignum(b, key->e);
	426	buffer_put_bignum(b, key->d);
	427	/* To keep within the protocol: p < q for ssh. in SSL p > q */
	428	buffer_put_bignum(b, key->iqmp); /* ssh key->u */
	429	buffer_put_bignum(b, key->q); /* ssh key->p, SSL key->q */
	430	buffer_put_bignum(b, key->p); /* ssh key->q, SSL key->p */
	431	buffer_put_string(b, comment, strlen(comment));
	432	}
	433
	434	void
fa08c86b	435	ssh_encode_identity_ssh2(Buffer b, Key key, const char *comment)
4c8722d9	436	{
	437	buffer_clear(b);
	438	buffer_put_char(b, SSH2_AGENTC_ADD_IDENTITY);
fa08c86b	439	buffer_put_cstring(b, key_ssh_name(key));
	440	switch(key->type){
	441	case KEY_RSA:
	442	buffer_put_bignum2(b, key->rsa->n);
	443	buffer_put_bignum2(b, key->rsa->e);
	444	buffer_put_bignum2(b, key->rsa->d);
	445	buffer_put_bignum2(b, key->rsa->iqmp);
	446	buffer_put_bignum2(b, key->rsa->p);
	447	buffer_put_bignum2(b, key->rsa->q);
	448	break;
	449	case KEY_DSA:
	450	buffer_put_bignum2(b, key->dsa->p);
	451	buffer_put_bignum2(b, key->dsa->q);
	452	buffer_put_bignum2(b, key->dsa->g);
	453	buffer_put_bignum2(b, key->dsa->pub_key);
	454	buffer_put_bignum2(b, key->dsa->priv_key);
	455	break;
	456	}
	457	buffer_put_cstring(b, comment);
4c8722d9	458	}
4c8722d9	459
aa3378df	460	/*
	461	* Adds an identity to the authentication server. This call is not meant to
	462	* be used by normal applications.
	463	*/
8efc0c15	464
6ae2364d	465	int
4c8722d9	466	ssh_add_identity(AuthenticationConnection auth, Key key, const char *comment)
8efc0c15	467	{
2e73a022	468	Buffer msg;
c345cf9d	469	int type;
5260325f	470
2e73a022	471	buffer_init(&msg);
4c8722d9	472
4c8722d9	473	switch (key->type) {
fa08c86b	474	case KEY_RSA1:
fa08c86b	475	ssh_encode_identity_rsa1(&msg, key->rsa, comment);
4c8722d9	476	break;
fa08c86b	477	case KEY_RSA:
4c8722d9	478	case KEY_DSA:
fa08c86b	479	ssh_encode_identity_ssh2(&msg, key, comment);
4c8722d9	480	break;
4c8722d9	481	default:
2e73a022	482	buffer_free(&msg);
4c8722d9	483	return 0;
	484	break;
	485	}
2e73a022	486	if (ssh_request_reply(auth, &msg, &msg) == 0) {
2e73a022	487	buffer_free(&msg);
5260325f	488	return 0;
5260325f	489	}
2e73a022	490	type = buffer_get_char(&msg);
2e73a022	491	buffer_free(&msg);
c345cf9d	492	return decode_reply(type);
5260325f	493	}
5260325f	494
aa3378df	495	/*
	496	* Removes an identity from the authentication server. This call is not
	497	* meant to be used by normal applications.
	498	*/
8efc0c15	499
6ae2364d	500	int
2e73a022	501	ssh_remove_identity(AuthenticationConnection auth, Key key)
8efc0c15	502	{
2e73a022	503	Buffer msg;
c345cf9d	504	int type;
1e3b8b07	505	u_char *blob;
1e3b8b07	506	u_int blen;
2e73a022	507
	508	buffer_init(&msg);
	509
fa08c86b	510	if (key->type == KEY_RSA1) {
2e73a022	511	buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
	512	buffer_put_int(&msg, BN_num_bits(key->rsa->n));
	513	buffer_put_bignum(&msg, key->rsa->e);
	514	buffer_put_bignum(&msg, key->rsa->n);
fa08c86b	515	} else if (key->type == KEY_DSA \|\| key->type == KEY_RSA) {
fa08c86b	516	key_to_blob(key, &blob, &blen);
2e73a022	517	buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
	518	buffer_put_string(&msg, blob, blen);
	519	xfree(blob);
	520	} else {
	521	buffer_free(&msg);
5260325f	522	return 0;
5260325f	523	}
2e73a022	524	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	525	buffer_free(&msg);
	526	return 0;
	527	}
	528	type = buffer_get_char(&msg);
	529	buffer_free(&msg);
c345cf9d	530	return decode_reply(type);
5260325f	531	}
5260325f	532
aa3378df	533	/*
	534	* Removes all identities from the agent. This call is not meant to be used
	535	* by normal applications.
	536	*/
8efc0c15	537
6ae2364d	538	int
2e73a022	539	ssh_remove_all_identities(AuthenticationConnection *auth, int version)
8efc0c15	540	{
2e73a022	541	Buffer msg;
c345cf9d	542	int type;
2e73a022	543	int code = (version==1) ?
	544	SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
	545	SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
5260325f	546
2e73a022	547	buffer_init(&msg);
2e73a022	548	buffer_put_char(&msg, code);
5260325f	549
2e73a022	550	if (ssh_request_reply(auth, &msg, &msg) == 0) {
2e73a022	551	buffer_free(&msg);
5260325f	552	return 0;
5260325f	553	}
2e73a022	554	type = buffer_get_char(&msg);
2e73a022	555	buffer_free(&msg);
c345cf9d	556	return decode_reply(type);
089fbbd2	557	}
089fbbd2	558
2b87da3b	559	int
c345cf9d	560	decode_reply(int type)
089fbbd2	561	{
5260325f	562	switch (type) {
5260325f	563	case SSH_AGENT_FAILURE:
94ec8c6b	564	case SSH_COM_AGENT2_FAILURE:
c345cf9d	565	log("SSH_AGENT_FAILURE");
5260325f	566	return 0;
5260325f	567	case SSH_AGENT_SUCCESS:
5260325f	568	return 1;
5260325f	569	default:
089fbbd2	570	fatal("Bad response from authentication agent: %d", type);
8efc0c15	571	}
5260325f	572	/* NOTREACHED */
	573	return 0;
	574	}