[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 1.58 2003/01/23 13:50:27 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"

static int agent_present = 0;

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

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

int
ssh_agent_present(void)
{
	int authfd;

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

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

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

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

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

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

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

static int
ssh_request_reply(AuthenticationConnection *auth, Buffer *request, Buffer *reply)
{
	int l, 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, 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, u_int confirm)
{
	Buffer msg;
	int type, constrained = (life || confirm);

	buffer_init(&msg);

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

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

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

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

	buffer_init(&msg);

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

int
ssh_update_card(AuthenticationConnection *auth, int add, const char *reader_id, const char *pin)
{
	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"
6a9b3198	38	RCSID("$OpenBSD: authfd.c,v 1.58 2003/01/23 13:50:27 markus Exp $");
3c0ef626	39
	40	#include <openssl/evp.h>
	41
	42	#include "ssh.h"
	43	#include "rsa.h"
	44	#include "buffer.h"
	45	#include "bufaux.h"
	46	#include "xmalloc.h"
	47	#include "getput.h"
	48	#include "key.h"
	49	#include "authfd.h"
	50	#include "cipher.h"
	51	#include "kex.h"
	52	#include "compat.h"
	53	#include "log.h"
	54	#include "atomicio.h"
	55
41b2f314	56	static int agent_present = 0;
41b2f314	57
3c0ef626	58	/* helper */
	59	int decode_reply(int type);
	60
	61	/* macro to check for "agent failure" message */
	62	#define agent_failed(x) \
	63	((x == SSH_AGENT_FAILURE) \|\| (x == SSH_COM_AGENT2_FAILURE) \|\| \
f5799ae1	64	(x == SSH2_AGENT_FAILURE))
3c0ef626	65
41b2f314	66	int
	67	ssh_agent_present(void)
	68	{
	69	int authfd;
	70
	71	if (agent_present)
	72	return 1;
	73	if ((authfd = ssh_get_authentication_socket()) == -1)
	74	return 0;
	75	else {
	76	ssh_close_authentication_socket(authfd);
	77	return 1;
	78	}
	79	}
	80
3c0ef626	81	/* Returns the number of the authentication fd, or -1 if there is none. */
	82
	83	int
	84	ssh_get_authentication_socket(void)
	85	{
	86	const char *authsocket;
	87	int sock;
	88	struct sockaddr_un sunaddr;
	89
	90	authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
	91	if (!authsocket)
	92	return -1;
	93
	94	sunaddr.sun_family = AF_UNIX;
	95	strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
	96
	97	sock = socket(AF_UNIX, SOCK_STREAM, 0);
	98	if (sock < 0)
	99	return -1;
	100
	101	/* close on exec */
	102	if (fcntl(sock, F_SETFD, 1) == -1) {
	103	close(sock);
	104	return -1;
	105	}
	106	if (connect(sock, (struct sockaddr *) &sunaddr, sizeof sunaddr) < 0) {
	107	close(sock);
	108	return -1;
	109	}
41b2f314	110	agent_present = 1;
3c0ef626	111	return sock;
	112	}
	113
	114	static int
	115	ssh_request_reply(AuthenticationConnection auth, Buffer request, Buffer *reply)
	116	{
	117	int l, len;
	118	char buf[1024];
	119
	120	/* Get the length of the message, and format it in the buffer. */
	121	len = buffer_len(request);
	122	PUT_32BIT(buf, len);
	123
	124	/* Send the length and then the packet to the agent. */
	125	if (atomicio(write, auth->fd, buf, 4) != 4 \|\|
	126	atomicio(write, auth->fd, buffer_ptr(request),
	127	buffer_len(request)) != buffer_len(request)) {
	128	error("Error writing to authentication socket.");
	129	return 0;
	130	}
	131	/*
	132	* Wait for response from the agent. First read the length of the
	133	* response packet.
	134	*/
	135	len = 4;
	136	while (len > 0) {
	137	l = read(auth->fd, buf + 4 - len, len);
	138	if (l == -1 && (errno == EAGAIN \|\| errno == EINTR))
	139	continue;
	140	if (l <= 0) {
	141	error("Error reading response length from authentication socket.");
	142	return 0;
	143	}
	144	len -= l;
	145	}
	146
	147	/* Extract the length, and check it for sanity. */
	148	len = GET_32BIT(buf);
	149	if (len > 256 * 1024)
	150	fatal("Authentication response too long: %d", len);
	151
	152	/* Read the rest of the response in to the buffer. */
	153	buffer_clear(reply);
	154	while (len > 0) {
	155	l = len;
	156	if (l > sizeof(buf))
	157	l = sizeof(buf);
	158	l = read(auth->fd, buf, l);
	159	if (l == -1 && (errno == EAGAIN \|\| errno == EINTR))
	160	continue;
	161	if (l <= 0) {
	162	error("Error reading response from authentication socket.");
	163	return 0;
	164	}
680cee3b	165	buffer_append(reply, buf, l);
3c0ef626	166	len -= l;
	167	}
	168	return 1;
	169	}
	170
	171	/*
	172	* Closes the agent socket if it should be closed (depends on how it was
	173	* obtained). The argument must have been returned by
	174	* ssh_get_authentication_socket().
	175	*/
	176
	177	void
	178	ssh_close_authentication_socket(int sock)
	179	{
	180	if (getenv(SSH_AUTHSOCKET_ENV_NAME))
	181	close(sock);
	182	}
	183
	184	/*
	185	* Opens and connects a private socket for communication with the
	186	* authentication agent. Returns the file descriptor (which must be
	187	* shut down and closed by the caller when no longer needed).
	188	* Returns NULL if an error occurred and the connection could not be
	189	* opened.
	190	*/
	191
	192	AuthenticationConnection *
	193	ssh_get_authentication_connection(void)
	194	{
	195	AuthenticationConnection *auth;
	196	int sock;
	197
	198	sock = ssh_get_authentication_socket();
	199
	200	/*
	201	* Fail if we couldn't obtain a connection. This happens if we
	202	* exited due to a timeout.
	203	*/
	204	if (sock < 0)
	205	return NULL;
	206
	207	auth = xmalloc(sizeof(*auth));
	208	auth->fd = sock;
	209	buffer_init(&auth->identities);
	210	auth->howmany = 0;
	211
	212	return auth;
	213	}
	214
	215	/*
	216	* Closes the connection to the authentication agent and frees any associated
	217	* memory.
	218	*/
	219
	220	void
	221	ssh_close_authentication_connection(AuthenticationConnection *auth)
	222	{
	223	buffer_free(&auth->identities);
	224	close(auth->fd);
	225	xfree(auth);
	226	}
	227
f5799ae1	228	/* Lock/unlock agent */
	229	int
	230	ssh_lock_agent(AuthenticationConnection auth, int lock, const char password)
	231	{
	232	int type;
	233	Buffer msg;
	234
	235	buffer_init(&msg);
	236	buffer_put_char(&msg, lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK);
	237	buffer_put_cstring(&msg, password);
	238
	239	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	240	buffer_free(&msg);
	241	return 0;
	242	}
	243	type = buffer_get_char(&msg);
	244	buffer_free(&msg);
	245	return decode_reply(type);
	246	}
	247
3c0ef626	248	/*
	249	* Returns the first authentication identity held by the agent.
	250	*/
	251
	252	int
	253	ssh_get_num_identities(AuthenticationConnection *auth, int version)
	254	{
	255	int type, code1 = 0, code2 = 0;
	256	Buffer request;
	257
e9a17296	258	switch (version) {
3c0ef626	259	case 1:
	260	code1 = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
	261	code2 = SSH_AGENT_RSA_IDENTITIES_ANSWER;
	262	break;
	263	case 2:
	264	code1 = SSH2_AGENTC_REQUEST_IDENTITIES;
	265	code2 = SSH2_AGENT_IDENTITIES_ANSWER;
	266	break;
	267	default:
	268	return 0;
	269	}
	270
	271	/*
	272	* Send a message to the agent requesting for a list of the
	273	* identities it can represent.
	274	*/
	275	buffer_init(&request);
	276	buffer_put_char(&request, code1);
	277
	278	buffer_clear(&auth->identities);
	279	if (ssh_request_reply(auth, &request, &auth->identities) == 0) {
	280	buffer_free(&request);
	281	return 0;
	282	}
	283	buffer_free(&request);
	284
	285	/* Get message type, and verify that we got a proper answer. */
	286	type = buffer_get_char(&auth->identities);
	287	if (agent_failed(type)) {
	288	return 0;
	289	} else if (type != code2) {
	290	fatal("Bad authentication reply message type: %d", type);
	291	}
	292
	293	/* Get the number of entries in the response and check it for sanity. */
	294	auth->howmany = buffer_get_int(&auth->identities);
	295	if (auth->howmany > 1024)
	296	fatal("Too many identities in authentication reply: %d",
	297	auth->howmany);
	298
	299	return auth->howmany;
	300	}
	301
	302	Key *
	303	ssh_get_first_identity(AuthenticationConnection auth, char *comment, int version)
	304	{
	305	/* get number of identities and return the first entry (if any). */
	306	if (ssh_get_num_identities(auth, version) > 0)
	307	return ssh_get_next_identity(auth, comment, version);
	308	return NULL;
	309	}
	310
	311	Key *
	312	ssh_get_next_identity(AuthenticationConnection auth, char *comment, int version)
	313	{
	314	u_int bits;
	315	u_char *blob;
	316	u_int blen;
	317	Key *key = NULL;
	318
	319	/* Return failure if no more entries. */
	320	if (auth->howmany <= 0)
	321	return NULL;
	322
323	/*
324	* Get the next entry from the packet. These will abort with a fatal
325	* error if the packet is too short or contains corrupt data.
326	*/
e9a17296	327	switch (version) {
3c0ef626	328	case 1:
	329	key = key_new(KEY_RSA1);
	330	bits = buffer_get_int(&auth->identities);
	331	buffer_get_bignum(&auth->identities, key->rsa->e);
	332	buffer_get_bignum(&auth->identities, key->rsa->n);
	333	*comment = buffer_get_string(&auth->identities, NULL);
	334	if (bits != BN_num_bits(key->rsa->n))
	335	log("Warning: identity keysize mismatch: actual %d, announced %u",
	336	BN_num_bits(key->rsa->n), bits);
	337	break;
	338	case 2:
	339	blob = buffer_get_string(&auth->identities, &blen);
	340	*comment = buffer_get_string(&auth->identities, NULL);
	341	key = key_from_blob(blob, blen);
	342	xfree(blob);
	343	break;
	344	default:
	345	return NULL;
	346	break;
	347	}
	348	/* Decrement the number of remaining entries. */
	349	auth->howmany--;
	350	return key;
	351	}
	352
	353	/*
	354	* Generates a random challenge, sends it to the agent, and waits for
	355	* response from the agent. Returns true (non-zero) if the agent gave the
	356	* correct answer, zero otherwise. Response type selects the style of
	357	* response desired, with 0 corresponding to protocol version 1.0 (no longer
	358	* supported) and 1 corresponding to protocol version 1.1.
	359	*/
	360
	361	int
	362	ssh_decrypt_challenge(AuthenticationConnection *auth,
	363	Key* key, BIGNUM *challenge,
	364	u_char session_id[16],
	365	u_int response_type,
	366	u_char response[16])
	367	{
	368	Buffer buffer;
	369	int success = 0;
	370	int i;
	371	int type;
	372
	373	if (key->type != KEY_RSA1)
	374	return 0;
	375	if (response_type == 0) {
	376	log("Compatibility with ssh protocol version 1.0 no longer supported.");
	377	return 0;
	378	}
	379	buffer_init(&buffer);
	380	buffer_put_char(&buffer, SSH_AGENTC_RSA_CHALLENGE);
	381	buffer_put_int(&buffer, BN_num_bits(key->rsa->n));
	382	buffer_put_bignum(&buffer, key->rsa->e);
	383	buffer_put_bignum(&buffer, key->rsa->n);
	384	buffer_put_bignum(&buffer, challenge);
e9a17296	385	buffer_append(&buffer, session_id, 16);
3c0ef626	386	buffer_put_int(&buffer, response_type);
	387
	388	if (ssh_request_reply(auth, &buffer, &buffer) == 0) {
	389	buffer_free(&buffer);
	390	return 0;
	391	}
	392	type = buffer_get_char(&buffer);
	393
	394	if (agent_failed(type)) {
	395	log("Agent admitted failure to authenticate using the key.");
	396	} else if (type != SSH_AGENT_RSA_RESPONSE) {
	397	fatal("Bad authentication response: %d", type);
	398	} else {
	399	success = 1;
	400	/*
	401	* Get the response from the packet. This will abort with a
	402	* fatal error if the packet is corrupt.
	403	*/
	404	for (i = 0; i < 16; i++)
	405	response[i] = buffer_get_char(&buffer);
	406	}
	407	buffer_free(&buffer);
	408	return success;
	409	}
	410
	411	/* ask agent to sign data, returns -1 on error, 0 on success */
	412	int
	413	ssh_agent_sign(AuthenticationConnection *auth,
	414	Key *key,
e9a17296	415	u_char *sigp, u_int lenp,
e9a17296	416	u_char *data, u_int datalen)
3c0ef626	417	{
	418	extern int datafellows;
	419	Buffer msg;
	420	u_char *blob;
	421	u_int blen;
	422	int type, flags = 0;
	423	int ret = -1;
	424
	425	if (key_to_blob(key, &blob, &blen) == 0)
	426	return -1;
	427
	428	if (datafellows & SSH_BUG_SIGBLOB)
	429	flags = SSH_AGENT_OLD_SIGNATURE;
	430
	431	buffer_init(&msg);
	432	buffer_put_char(&msg, SSH2_AGENTC_SIGN_REQUEST);
	433	buffer_put_string(&msg, blob, blen);
	434	buffer_put_string(&msg, data, datalen);
	435	buffer_put_int(&msg, flags);
	436	xfree(blob);
	437
	438	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	439	buffer_free(&msg);
	440	return -1;
	441	}
	442	type = buffer_get_char(&msg);
	443	if (agent_failed(type)) {
	444	log("Agent admitted failure to sign using the key.");
	445	} else if (type != SSH2_AGENT_SIGN_RESPONSE) {
	446	fatal("Bad authentication response: %d", type);
	447	} else {
	448	ret = 0;
	449	*sigp = buffer_get_string(&msg, lenp);
	450	}
	451	buffer_free(&msg);
	452	return ret;
	453	}
	454
	455	/* Encode key for a message to the agent. */
	456
	457	static void
	458	ssh_encode_identity_rsa1(Buffer b, RSA key, const char *comment)
	459	{
3c0ef626	460	buffer_put_int(b, BN_num_bits(key->n));
	461	buffer_put_bignum(b, key->n);
	462	buffer_put_bignum(b, key->e);
	463	buffer_put_bignum(b, key->d);
	464	/* To keep within the protocol: p < q for ssh. in SSL p > q */
	465	buffer_put_bignum(b, key->iqmp); /* ssh key->u */
	466	buffer_put_bignum(b, key->q); /* ssh key->p, SSL key->q */
	467	buffer_put_bignum(b, key->p); /* ssh key->q, SSL key->p */
	468	buffer_put_cstring(b, comment);
	469	}
	470
	471	static void
	472	ssh_encode_identity_ssh2(Buffer b, Key key, const char *comment)
	473	{
3c0ef626	474	buffer_put_cstring(b, key_ssh_name(key));
e9a17296	475	switch (key->type) {
3c0ef626	476	case KEY_RSA:
	477	buffer_put_bignum2(b, key->rsa->n);
	478	buffer_put_bignum2(b, key->rsa->e);
	479	buffer_put_bignum2(b, key->rsa->d);
	480	buffer_put_bignum2(b, key->rsa->iqmp);
	481	buffer_put_bignum2(b, key->rsa->p);
	482	buffer_put_bignum2(b, key->rsa->q);
	483	break;
	484	case KEY_DSA:
	485	buffer_put_bignum2(b, key->dsa->p);
	486	buffer_put_bignum2(b, key->dsa->q);
	487	buffer_put_bignum2(b, key->dsa->g);
	488	buffer_put_bignum2(b, key->dsa->pub_key);
	489	buffer_put_bignum2(b, key->dsa->priv_key);
	490	break;
	491	}
	492	buffer_put_cstring(b, comment);
	493	}
	494
	495	/*
	496	* Adds an identity to the authentication server. This call is not meant to
	497	* be used by normal applications.
	498	*/
	499
	500	int
f5799ae1	501	ssh_add_identity_constrained(AuthenticationConnection auth, Key key,
6a9b3198	502	const char *comment, u_int life, u_int confirm)
3c0ef626	503	{
3c0ef626	504	Buffer msg;
6a9b3198	505	int type, constrained = (life \|\| confirm);
3c0ef626	506
	507	buffer_init(&msg);
	508
	509	switch (key->type) {
	510	case KEY_RSA1:
f5799ae1	511	type = constrained ?
	512	SSH_AGENTC_ADD_RSA_ID_CONSTRAINED :
	513	SSH_AGENTC_ADD_RSA_IDENTITY;
	514	buffer_put_char(&msg, type);
3c0ef626	515	ssh_encode_identity_rsa1(&msg, key->rsa, comment);
	516	break;
	517	case KEY_RSA:
	518	case KEY_DSA:
f5799ae1	519	type = constrained ?
	520	SSH2_AGENTC_ADD_ID_CONSTRAINED :
	521	SSH2_AGENTC_ADD_IDENTITY;
	522	buffer_put_char(&msg, type);
3c0ef626	523	ssh_encode_identity_ssh2(&msg, key, comment);
	524	break;
	525	default:
	526	buffer_free(&msg);
	527	return 0;
	528	break;
	529	}
f5799ae1	530	if (constrained) {
	531	if (life != 0) {
	532	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_LIFETIME);
	533	buffer_put_int(&msg, life);
	534	}
6a9b3198	535	if (confirm != 0)
6a9b3198	536	buffer_put_char(&msg, SSH_AGENT_CONSTRAIN_CONFIRM);
f5799ae1	537	}
3c0ef626	538	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	539	buffer_free(&msg);
	540	return 0;
	541	}
	542	type = buffer_get_char(&msg);
	543	buffer_free(&msg);
	544	return decode_reply(type);
	545	}
	546
f5799ae1	547	int
	548	ssh_add_identity(AuthenticationConnection auth, Key key, const char *comment)
	549	{
6a9b3198	550	return ssh_add_identity_constrained(auth, key, comment, 0, 0);
f5799ae1	551	}
f5799ae1	552
3c0ef626	553	/*
	554	* Removes an identity from the authentication server. This call is not
	555	* meant to be used by normal applications.
	556	*/
	557
	558	int
	559	ssh_remove_identity(AuthenticationConnection auth, Key key)
	560	{
	561	Buffer msg;
	562	int type;
	563	u_char *blob;
	564	u_int blen;
	565
	566	buffer_init(&msg);
	567
	568	if (key->type == KEY_RSA1) {
	569	buffer_put_char(&msg, SSH_AGENTC_REMOVE_RSA_IDENTITY);
	570	buffer_put_int(&msg, BN_num_bits(key->rsa->n));
	571	buffer_put_bignum(&msg, key->rsa->e);
	572	buffer_put_bignum(&msg, key->rsa->n);
	573	} else if (key->type == KEY_DSA \|\| key->type == KEY_RSA) {
	574	key_to_blob(key, &blob, &blen);
	575	buffer_put_char(&msg, SSH2_AGENTC_REMOVE_IDENTITY);
	576	buffer_put_string(&msg, blob, blen);
	577	xfree(blob);
	578	} else {
	579	buffer_free(&msg);
	580	return 0;
	581	}
	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	int
700318f3	592	ssh_update_card(AuthenticationConnection auth, int add, const char reader_id, const char *pin)
3c0ef626	593	{
	594	Buffer msg;
	595	int type;
	596
	597	buffer_init(&msg);
	598	buffer_put_char(&msg, add ? SSH_AGENTC_ADD_SMARTCARD_KEY :
	599	SSH_AGENTC_REMOVE_SMARTCARD_KEY);
	600	buffer_put_cstring(&msg, reader_id);
700318f3	601	buffer_put_cstring(&msg, pin);
3c0ef626	602	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	603	buffer_free(&msg);
	604	return 0;
	605	}
	606	type = buffer_get_char(&msg);
	607	buffer_free(&msg);
	608	return decode_reply(type);
	609	}
	610
	611	/*
	612	* Removes all identities from the agent. This call is not meant to be used
	613	* by normal applications.
	614	*/
	615
	616	int
	617	ssh_remove_all_identities(AuthenticationConnection *auth, int version)
	618	{
	619	Buffer msg;
	620	int type;
	621	int code = (version==1) ?
	622	SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES :
	623	SSH2_AGENTC_REMOVE_ALL_IDENTITIES;
	624
	625	buffer_init(&msg);
	626	buffer_put_char(&msg, code);
	627
	628	if (ssh_request_reply(auth, &msg, &msg) == 0) {
	629	buffer_free(&msg);
	630	return 0;
	631	}
	632	type = buffer_get_char(&msg);
	633	buffer_free(&msg);
	634	return decode_reply(type);
	635	}
	636
	637	int
	638	decode_reply(int type)
	639	{
	640	switch (type) {
	641	case SSH_AGENT_FAILURE:
	642	case SSH_COM_AGENT2_FAILURE:
	643	case SSH2_AGENT_FAILURE:
	644	log("SSH_AGENT_FAILURE");
	645	return 0;
	646	case SSH_AGENT_SUCCESS:
	647	return 1;
	648	default:
	649	fatal("Bad response from authentication agent: %d", type);
	650	}
	651	/* NOTREACHED */
	652	return 0;
	653	}