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|
/* $OpenBSD: authfd.c,v 1.117 2019/09/03 08:29:15 djm Exp $ */
/*
* 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"
#include <sys/types.h>
#include <sys/un.h>
#include <sys/socket.h>
#include <fcntl.h>
#include <stdlib.h>
#include <signal.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include "xmalloc.h"
#include "ssh.h"
#include "sshbuf.h"
#include "sshkey.h"
#include "authfd.h"
#include "cipher.h"
#include "compat.h"
#include "log.h"
#include "atomicio.h"
#include "misc.h"
#include "ssherr.h"
#define MAX_AGENT_IDENTITIES 2048 /* Max keys in agent reply */
#define MAX_AGENT_REPLY_LEN (256 * 1024) /* Max bytes in agent reply */
/* macro to check for "agent failure" message */
#define agent_failed(x) \
((x == SSH_AGENT_FAILURE) || \
(x == SSH_COM_AGENT2_FAILURE) || \
(x == SSH2_AGENT_FAILURE))
/* Convert success/failure response from agent to a err.h status */
static int
decode_reply(u_char type)
{
if (agent_failed(type))
return SSH_ERR_AGENT_FAILURE;
else if (type == SSH_AGENT_SUCCESS)
return 0;
else
return SSH_ERR_INVALID_FORMAT;
}
/* Returns the number of the authentication fd, or -1 if there is none. */
int
ssh_get_authentication_socket(int *fdp)
{
const char *authsocket;
int sock, oerrno;
struct sockaddr_un sunaddr;
if (fdp != NULL)
*fdp = -1;
authsocket = getenv(SSH_AUTHSOCKET_ENV_NAME);
if (authsocket == NULL || *authsocket == '\0')
return SSH_ERR_AGENT_NOT_PRESENT;
memset(&sunaddr, 0, sizeof(sunaddr));
sunaddr.sun_family = AF_UNIX;
strlcpy(sunaddr.sun_path, authsocket, sizeof(sunaddr.sun_path));
if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
return SSH_ERR_SYSTEM_ERROR;
/* close on exec */
if (fcntl(sock, F_SETFD, FD_CLOEXEC) == -1 ||
connect(sock, (struct sockaddr *)&sunaddr, sizeof(sunaddr)) == -1) {
oerrno = errno;
close(sock);
errno = oerrno;
return SSH_ERR_SYSTEM_ERROR;
}
if (fdp != NULL)
*fdp = sock;
else
close(sock);
return 0;
}
/* Communicate with agent: send request and read reply */
static int
ssh_request_reply(int sock, struct sshbuf *request, struct sshbuf *reply)
{
int r;
size_t l, len;
char buf[1024];
/* Get the length of the message, and format it in the buffer. */
len = sshbuf_len(request);
POKE_U32(buf, len);
/* Send the length and then the packet to the agent. */
if (atomicio(vwrite, sock, buf, 4) != 4 ||
atomicio(vwrite, sock, sshbuf_mutable_ptr(request),
sshbuf_len(request)) != sshbuf_len(request))
return SSH_ERR_AGENT_COMMUNICATION;
/*
* Wait for response from the agent. First read the length of the
* response packet.
*/
if (atomicio(read, sock, buf, 4) != 4)
return SSH_ERR_AGENT_COMMUNICATION;
/* Extract the length, and check it for sanity. */
len = PEEK_U32(buf);
if (len > MAX_AGENT_REPLY_LEN)
return SSH_ERR_INVALID_FORMAT;
/* Read the rest of the response in to the buffer. */
sshbuf_reset(reply);
while (len > 0) {
l = len;
if (l > sizeof(buf))
l = sizeof(buf);
if (atomicio(read, sock, buf, l) != l)
return SSH_ERR_AGENT_COMMUNICATION;
if ((r = sshbuf_put(reply, buf, l)) != 0)
return r;
len -= l;
}
return 0;
}
/*
* 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);
}
/* Lock/unlock agent */
int
ssh_lock_agent(int sock, int lock, const char *password)
{
int r;
u_char type = lock ? SSH_AGENTC_LOCK : SSH_AGENTC_UNLOCK;
struct sshbuf *msg;
if ((msg = sshbuf_new()) == NULL)
return SSH_ERR_ALLOC_FAIL;
if ((r = sshbuf_put_u8(msg, type)) != 0 ||
(r = sshbuf_put_cstring(msg, password)) != 0)
goto out;
if ((r = ssh_request_reply(sock, msg, msg)) != 0)
goto out;
if ((r = sshbuf_get_u8(msg, &type)) != 0)
goto out;
r = decode_reply(type);
out:
sshbuf_free(msg);
return r;
}
static int
deserialise_identity2(struct sshbuf *ids, struct sshkey **keyp, char **commentp)
{
int r;
char *comment = NULL;
const u_char *blob;
size_t blen;
if ((r = sshbuf_get_string_direct(ids, &blob, &blen)) != 0 ||
(r = sshbuf_get_cstring(ids, &comment, NULL)) != 0)
goto out;
if ((r = sshkey_from_blob(blob, blen, keyp)) != 0)
goto out;
if (commentp != NULL) {
*commentp = comment;
comment = NULL;
}
r = 0;
out:
free(comment);
return r;
}
/*
* Fetch list of identities held by the agent.
*/
int
ssh_fetch_identitylist(int sock, struct ssh_identitylist **idlp)
{
u_char type;
u_int32_t num, i;
struct sshbuf *msg;
struct ssh_identitylist *idl = NULL<
|