#define DEBUG
/*
* daemon.c
* --------
* A daemon to arbitrate shared access to a serial connection to the HSM.
*
* Copyright (c) 2016, NORDUnet A/S All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - 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.
*
* - Neither the name of the NORDUnet nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT
* HOLDER OR CONTRIBUTORS 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 <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <poll.h>
#include <getopt.h> /* required with -std=c99 */
#include <termios.h> /* for default speed */
#include "slip_internal.h"
#include "xdr_internal.h"
static char usage[] =
"usage: %s [-n socketname] [-d ttydevice] [-s ttyspeed]\n";
/* select() is hopelessly broken, and epoll() is Linux-specific, so we'll use
* poll() until such a time as libevent or libev seems more appropriate.
* Unfortunately, poll() doesn't come with any macros or functions to manage
* the pollfd array, so we have to invent them.
*/
static struct pollfd *pollfds = NULL;
static nfds_t nfds = 0;
static nfds_t npollfds = 0;
static void poll_add(int fd)
{
/* add 4 entries at a time to avoid having to realloc too often */
#define NNEW 4
/* expand the array if necessary */
if (nfds == npollfds) {
npollfds = nfds + NNEW;
pollfds = realloc(pollfds, npollfds * sizeof(struct pollfd));
if (pollfds == NULL) {
perror("realloc");
exit(EXIT_FAILURE);
}
/* zero the new entries for hygiene */
memset(&pollfds[nfds], 0, NNEW * sizeof(struct pollfd));
}
/* populate the new entry */
pollfds[nfds].fd = fd;
pollfds[nfds].events = POLLIN;
++nfds;
}
static void poll_remove(int fd)
{
nfds_t i;
/* search the pollfd array */
for (i = 0; i < nfds; ++i) {
if (pollfds[i].fd == fd) {
/* shift remainder of the array left by one */
memmove(&pollfds[i], &pollfds[i + 1], (nfds - i - 1) * sizeof(struct pollfd));
/* zero the last entry for hygiene */
memset(&pollfds[nfds - 1], 0, sizeof(struct pollfd));
--nfds;
return;
}
}
/* if it's not found, return without an error */
}
#ifndef MAX_PKT_SIZE /* move this to hal_internal.h */
#define MAX_PKT_SIZE 4096
#endif
typedef struct {
size_t len;
uint8_t buf[MAX_PKT_SIZE];
} rpc_buffer_t;
static rpc_buffer_t ibuf, obuf;
#ifndef DEVICE
#define DEVICE "/dev/ttyUSB0"
#endif
#ifndef SPEED
#define SPEED B921600
#endif
#ifndef SOCKET_NAME
#define SOCKET_NAME "/tmp/cryptechd.socket"
#endif
char *socket_name = SOCKET_NAME;
/* Set up an atexit handler to remove the filesystem entry for the unix domain
* socket. This will trigger on error exits, but not on the "normal" SIGKILL.
*/
void atexit_cleanup(void)
{
unlink(socket_name);
}
#ifdef DEBUG
static void hexdump(uint8_t *buf, uint32_t len)
{
for (uint32_t i = 0; i < len; ++i)
printf("%02x%c", buf[i], ((i & 0x07) == 0x07) ? '\n' : ' ');
if ((len & 0x07) != 0)
printf("\n");
}
#endif
int main(int argc, char *argv[])
{
struct sockaddr_un name;
int ret;
int lsock;
int dsock;
int opt;
char *device = DEVICE;
speed_t speed = SPEED;
while ((opt = getopt(argc, argv, "hn:d:s:")) != -1) {
switch (opt) {
case 'h':
printf(usage, argv[0]);
exit(EXIT_SUCCESS);
case 'n':
socket_name = optarg;
break;
case 'd':
device = optarg;
break;
case 's':
switch (atoi(optarg)) {
case 115200:
speed = B115200;
break;
case 921600:
speed = B921600;
break;
default:
printf("invalid speed value %s\n", optarg);
exit(EXIT_FAILURE);
}
break;
default:
printf(usage, argv[0]);
exit(EXIT_FAILURE);
}
}
if (atexit(atexit_cleanup) != 0) {
perror("atexit");
exit(EXIT_FAILURE);
}
if (hal_serial_init(device, speed) != HAL_OK)
exit(EXIT_FAILURE);
int serial_fd = hal_serial_get_fd();
poll_add(serial_fd);
/* Remove the filesystem entry for the unix domain socket. The usual way
* to stop a daemon is SIGKILL, which we can't catch, so the file remains,
* and will prevent us from binding the socket.
*
* XXX We should also scan the process table, to make sure the daemon
* isn't already running.
*/
unlink(socket_name);
/* Create the listening socket.
*/
lsock = socket(AF_UNIX, SOCK_SEQPACKET, 0);
if (lsock == -1) {
perror("socket");
exit(EXIT_FAILURE);
}
poll_add(lsock);
/* For portability, clear the whole address structure, since some
* implementations have additional (nonstandard) fields in the structure.
*/
memset(&name, 0, sizeof(struct sockaddr_un));
/* Bind the listening socket.
*/
name.sun_family = AF_UNIX;
strncpy(name.sun_path, socket_name, sizeof(name.sun_path) - 1);
ret = bind(lsock, (const struct sockaddr *) &name, sizeof(struct sockaddr_un));
if (ret == -1) {
perror("bind");
exit(EXIT_FAILURE);
}
/* Prepare to accept connections.
*/
ret = listen(lsock, 20);
if (ret == -1) {
perror("listen");
exit(EXIT_FAILURE);
}
/* The main loop.
*/
for (;;) {
/* Blocking poll on all descriptors of interest.
*/
ret = poll(pollfds, nfds, -1);
if (ret == -1) {
perror("poll");
exit(EXIT_FAILURE);
}
for (nfds_t i = 0; i < nfds; ++i) {
if (pollfds[i].revents != 0) {
/* XXX POLLERR|POLLHUP|POLLNVAL */
/* serial port */
if (pollfds[i].fd == serial_fd) {
int complete;
hal_slip_recv_char(ibuf.buf, &ibuf.len, sizeof(ibuf.buf), &complete);
if (complete) {
#ifdef DEBUG
printf("serial port received response:\n");
hexdump(ibuf.buf, ibuf.len);
#endif
/* We've got a complete rpc response packet. */
const uint8_t *bufptr = ibuf.buf;
const uint8_t * const limit = ibuf.buf + ibuf.len;
uint32_t sock;
/* First word of the response is the client ID. */
hal_xdr_decode_int(&bufptr, limit, &sock);
/* Pass response on to the client that requested it. */
send(sock, bufptr, ibuf.len - 4, 0);
/* Reinitialize the receive buffer. */
memset(&ibuf, 0, sizeof(ibuf));
}
}
/* listening socket */
else if (pollfds[i].fd == lsock) {
/* Accept incoming connection. */
dsock = accept(lsock, NULL, NULL);
if (ret == -1) {
perror("accept");
exit(EXIT_FAILURE);
}
poll_add(dsock);
#ifdef DEBUG
printf("listening socket accept data socket %d\n", dsock);
#endif
}
/* client data socket */
else {
uint8_t *bufptr = obuf.buf;
const uint8_t * const limit = obuf.buf + MAX_PKT_SIZE;
/* First word of the request is the client ID. */
hal_xdr_encode_int(&bufptr, limit, pollfds[i].fd);
/* Get the client's rpc request packet. */
obuf.len = recv(pollfds[i].fd, bufptr, MAX_PKT_SIZE - 4, 0);
#ifdef DEBUG
printf("data socket %d received request:\n", pollfds[i].fd);
hexdump(obuf.buf, obuf.len + 4);
#endif
/* Fill in the client handle arg as needed. */
uint32_t opcode;
hal_xdr_decode_int((const uint8_t ** const)&bufptr, limit, &opcode);
switch (opcode) {
case RPC_FUNC_SET_PIN:
case RPC_FUNC_LOGIN:
case RPC_FUNC_LOGOUT:
case RPC_FUNC_IS_LOGGED_IN:
case RPC_FUNC_HASH_INITIALIZE:
case RPC_FUNC_PKEY_LOAD:
case RPC_FUNC_PKEY_FIND:
case RPC_FUNC_PKEY_GENERATE_RSA:
case RPC_FUNC_PKEY_GENERATE_EC:
/* first argument is client handle */
hal_xdr_encode_int(&bufptr, limit, pollfds[i].fd);
break;
default:
break;
}
if (obuf.len > 0) {
#ifdef DEBUG
printf("passing to serial port\n");
#endif
/* Pass it on to the serial port. */
hal_slip_send(obuf.buf, obuf.len + 4);
}
else {
#ifdef DEBUG
printf("closing data socket\n");
#endif
/* Client has closed the socket. */
close(pollfds[i].fd);
poll_remove(pollfds[i].fd);
}
/* Reinitialize the transmit buffer. */
memset(&obuf, 0, sizeof(obuf));
}
}
}
}
/*NOTREACHED*/
exit(EXIT_SUCCESS);
}
