HardenedBSD/usr.sbin/ppp/server.c

/*-
 * Copyright (c) 1997 Brian Somers <brian@Awfulhak.org>
 * 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 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 AUTHOR 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.
 *
 * $FreeBSD$
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/un.h>

#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <termios.h>
#include <unistd.h>

#include "log.h"
#include "descriptor.h"
#include "server.h"
#include "id.h"
#include "prompt.h"

static int
server_UpdateSet(struct descriptor *d, fd_set *r, fd_set *w, fd_set *e, int *n)
{
  struct server *s = descriptor2server(d);
  struct prompt *p;
  int sets;

  sets = 0;
  if (r && s->fd >= 0) {
    if (*n < s->fd + 1)
      *n = s->fd + 1;
    FD_SET(s->fd, r);
    log_Printf(LogTIMER, "server: fdset(r) %d\n", s->fd);
    sets++;
  }

  for (p = log_PromptList(); p; p = p->next)
    sets += descriptor_UpdateSet(&p->desc, r, w, e, n);

  return sets;
}

static int
server_IsSet(struct descriptor *d, const fd_set *fdset)
{
  struct server *s = descriptor2server(d);
  struct prompt *p;

  if (s->fd >= 0 && FD_ISSET(s->fd, fdset))
    return 1;

  for (p = log_PromptList(); p; p = p->next)
    if (descriptor_IsSet(&p->desc, fdset))
      return 1;

  return 0;
}

#define IN_SIZE sizeof(struct sockaddr_in)
#define UN_SIZE sizeof(struct sockaddr_in)
#define ADDRSZ (IN_SIZE > UN_SIZE ? IN_SIZE : UN_SIZE)

static void
server_Read(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
{
  struct server *s = descriptor2server(d);
  char hisaddr[ADDRSZ];
  struct sockaddr *sa = (struct sockaddr *)hisaddr;
  struct sockaddr_in *in = (struct sockaddr_in *)hisaddr;
  int ssize = ADDRSZ, wfd;
  struct prompt *p;

  if (s->fd >= 0 && FD_ISSET(s->fd, fdset)) {
    wfd = accept(s->fd, sa, &ssize);
    if (wfd < 0)
      log_Printf(LogERROR, "server_Read: accept(): %s\n", strerror(errno));
  } else
    wfd = -1;

  if (wfd >= 0)
    switch (sa->sa_family) {
      case AF_LOCAL:
        log_Printf(LogPHASE, "Connected to local client.\n");
        break;

      case AF_INET:
        if (ntohs(in->sin_port) < 1024) {
          log_Printf(LogALERT, "Rejected client connection from %s:%u"
                    "(invalid port number) !\n",
                    inet_ntoa(in->sin_addr), ntohs(in->sin_port));
          close(wfd);
          wfd = -1;
          break;
        }
        log_Printf(LogPHASE, "Connected to client from %s:%u\n",
                  inet_ntoa(in->sin_addr), in->sin_port);
        break;

      default:
        write(wfd, "Unrecognised access !\n", 22);
        close(wfd);
        wfd = -1;
        break;
    }

  if (wfd >= 0) {
    if ((p = prompt_Create(s, bundle, wfd)) == NULL) {
      write(wfd, "Connection refused.\n", 20);
      close(wfd);
    } else {
      switch (sa->sa_family) {
        case AF_LOCAL:
          p->src.type = "local";
          strncpy(p->src.from, s->rm, sizeof p->src.from - 1);
          p->src.from[sizeof p->src.from - 1] = '\0';
          break;
        case AF_INET:
          p->src.type = "tcp";
          snprintf(p->src.from, sizeof p->src.from, "%s:%u",
                   inet_ntoa(in->sin_addr), in->sin_port);
          break;
      }
      prompt_TtyCommandMode(p);
      prompt_Required(p);
    }
  }

  log_PromptListChanged = 0;
  for (p = log_PromptList(); p; p = p->next)
    if (descriptor_IsSet(&p->desc, fdset)) {
      descriptor_Read(&p->desc, bundle, fdset);
      if (log_PromptListChanged)
        break;
    }
}

static int
server_Write(struct descriptor *d, struct bundle *bundle, const fd_set *fdset)
{
  /* We never want to write here ! */
  log_Printf(LogALERT, "server_Write: Internal error: Bad call !\n");
  return 0;
}

struct server server = {
  {
    SERVER_DESCRIPTOR,
    server_UpdateSet,
    server_IsSet,
    server_Read,
    server_Write
  },
  -1
};

int
server_LocalOpen(struct bundle *bundle, const char *name, mode_t mask)
{
  int s;

  if (server.rm && !strcmp(server.rm, name)) {
    if (chmod(server.rm, mask))
      log_Printf(LogERROR, "Local: chmod: %s\n", strerror(errno));
    return 0;
  }

  memset(&server.ifsun, '\0', sizeof server.ifsun);
  server.ifsun.sun_len = strlen(name);
  if (server.ifsun.sun_len > sizeof server.ifsun.sun_path - 1) {
    log_Printf(LogERROR, "Local: %s: Path too long\n", name);
    return 2;
  }
  server.ifsun.sun_family = AF_LOCAL;
  strcpy(server.ifsun.sun_path, name);

  s = ID0socket(PF_LOCAL, SOCK_STREAM, 0);
  if (s < 0) {
    log_Printf(LogERROR, "Local: socket: %s\n", strerror(errno));
    return 3;
  }
  setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &s, sizeof s);
  if (mask != (mode_t)-1)
    mask = umask(mask);
  if (bind(s, (struct sockaddr *)&server.ifsun, sizeof server.ifsun) < 0) {
    if (mask != (mode_t)-1)
      umask(mask);
    log_Printf(LogWARN, "Local: bind: %s\n", strerror(errno));
    close(s);
    return 4;
  }
  if (mask != (mode_t)-1)
    umask(mask);
  if (listen(s, 5) != 0) {
    log_Printf(LogERROR, "Local: Unable to listen to socket - BUNDLE overload?\n");
    close(s);
    ID0unlink(name);
    return 5;
  }
  server_Close(bundle);
  server.fd = s;
  server.rm = server.ifsun.sun_path;
  log_Printf(LogPHASE, "Listening at local socket %s.\n", name);
  return 0;
}

int
server_TcpOpen(struct bundle *bundle, int port)
{
  struct sockaddr_in ifsin;
  int s;

  if (server.port == port)
    return 0;

  s = ID0socket(PF_INET, SOCK_STREAM, 0);
  if (s < 0) {
    log_Printf(LogERROR, "Tcp: socket: %s\n", strerror(errno));
    return 7;
  }
  memset(&ifsin, '\0', sizeof ifsin);
  ifsin.sin_family = AF_INET;
  ifsin.sin_addr.s_addr = INADDR_ANY;
  ifsin.sin_port = htons(port);
  setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &s, sizeof s);
  if (bind(s, (struct sockaddr *)&ifsin, sizeof ifsin) < 0) {
    log_Printf(LogWARN, "Tcp: bind: %s\n", strerror(errno));
    close(s);
    return 8;
  }
  if (listen(s, 5) != 0) {
    log_Printf(LogERROR, "Tcp: Unable to listen to socket: %s\n",
               strerror(errno));
    close(s);
    return 9;
  }
  server_Close(bundle);
  server.fd = s;
  server.port = port;
  log_Printf(LogPHASE, "Listening at port %d.\n", port);
  return 0;
}

int
server_Close(struct bundle *bundle)
{
  if (server.fd >= 0) {
    if (server.rm) {
      struct sockaddr_un un;
      int sz = sizeof un;

      if (getsockname(server.fd, (struct sockaddr *)&un, &sz) == 0 &&
          un.sun_family == AF_LOCAL && sz == sizeof un)
        ID0unlink(un.sun_path);
      server.rm = NULL;
    }
    close(server.fd);
    server.fd = -1;
    server.port = 0;
    /* Drop associated prompts */
    log_DestroyPrompts(&server);
    return 1;
  }
  return 0;
}