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HardenedBSD/usr.sbin/ppp/main.c
Warner Losh b3e7694832 Remove $FreeBSD$: two-line .h pattern 
Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/
2023-08-16 11:54:16 -06:00

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C
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/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
* based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
* Internet Initiative Japan, Inc (IIJ)
* 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.
*/
#include <sys/param.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <sys/un.h>
#include <sys/socket.h>
#include <net/route.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <termios.h>
#include <unistd.h>
#include <sys/stat.h>
#ifndef NONAT
#ifdef LOCALNAT
#include "alias.h"
#else
#include <alias.h>
#endif
#endif
#include "layer.h"
#include "probe.h"
#include "mbuf.h"
#include "log.h"
#include "defs.h"
#include "id.h"
#include "timer.h"
#include "fsm.h"
#include "lqr.h"
#include "hdlc.h"
#include "lcp.h"
#include "ccp.h"
#include "iplist.h"
#include "throughput.h"
#include "slcompress.h"
#include "ncpaddr.h"
#include "ipcp.h"
#include "filter.h"
#include "descriptor.h"
#include "link.h"
#include "mp.h"
#ifndef NORADIUS
#include "radius.h"
#endif
#include "ipv6cp.h"
#include "ncp.h"
#include "bundle.h"
#include "auth.h"
#include "systems.h"
#include "sig.h"
#include "main.h"
#include "server.h"
#include "prompt.h"
#include "chat.h"
#include "chap.h"
#include "cbcp.h"
#include "datalink.h"
#include "iface.h"
#ifndef O_NONBLOCK
#ifdef O_NDELAY
#define O_NONBLOCK O_NDELAY
#endif
#endif
static void DoLoop(struct bundle *);
static void TerminalStop(int);
static struct bundle *SignalBundle;
static struct prompt *SignalPrompt;
struct libalias *la;
void
Cleanup(void)
{
SignalBundle->CleaningUp = 1;
bundle_Close(SignalBundle, NULL, CLOSE_STAYDOWN);
}
void
AbortProgram(int excode)
{
if (SignalBundle)
server_Close(SignalBundle);
log_Printf(LogPHASE, "PPP Terminated (%s).\n", ex_desc(excode));
if (SignalBundle) {
bundle_Close(SignalBundle, NULL, CLOSE_STAYDOWN);
bundle_Destroy(SignalBundle);
}
log_Close();
exit(excode);
}
static void
CloseConnection(int signo)
{
/* NOTE, these are manual, we've done a setsid() */
sig_signal(SIGINT, SIG_IGN);
log_Printf(LogPHASE, "Caught signal %d, abort connection(s)\n", signo);
bundle_Down(SignalBundle, CLOSE_STAYDOWN);
sig_signal(SIGINT, CloseConnection);
}
static void
CloseSession(int signo)
{
log_Printf(LogPHASE, "Signal %d, terminate.\n", signo);
Cleanup();
}
static pid_t BGPid = 0;
static void
KillChild(int signo)
{
signal(signo, SIG_IGN);
log_Printf(LogPHASE, "Parent: Signal %d\n", signo);
kill(BGPid, SIGINT);
}
static void
TerminalCont(int signo __unused)
{
signal(SIGCONT, SIG_DFL);
prompt_Continue(SignalPrompt);
}
static void
TerminalStop(int signo __unused)
{
prompt_Suspend(SignalPrompt);
signal(SIGCONT, TerminalCont);
raise(SIGSTOP);
}
static void
BringDownServer(int signo __unused)
{
/* Drops all child prompts too ! */
if (server_Close(SignalBundle))
log_Printf(LogPHASE, "Closed server socket\n");
}
static void
RestartServer(int signo __unused)
{
/* Drops all child prompts and re-opens the socket */
server_Reopen(SignalBundle);
}
static void
Usage(void)
{
fprintf(stderr, "usage: ppp [-auto | -foreground | -background | -direct |"
" -dedicated | -ddial | -interactive]"
#ifndef NONAT
" [-nat]"
#endif
" [-quiet] [-unit N] [system ...]\n");
exit(EX_START);
}
struct switches {
unsigned nat : 1;
unsigned fg : 1;
unsigned quiet : 1;
int mode;
int unit;
};
static int
ProcessArgs(int argc, char **argv, struct switches *sw)
{
int optc, newmode, arg;
char *cp;
optc = 0;
memset(sw, '\0', sizeof *sw);
sw->mode = PHYS_INTERACTIVE;
sw->unit = -1;
for (arg = 1; arg < argc && *argv[arg] == '-'; arg++, optc++) {
cp = argv[arg] + 1;
newmode = Nam2mode(cp);
switch (newmode) {
case PHYS_NONE:
if (strcmp(cp, "nat") == 0) {
#ifdef NONAT
log_Printf(LogWARN, "%s ignored: NAT is compiled out\n", argv[arg]);
#else
sw->nat = 1;
#endif
optc--; /* this option isn't exclusive */
} else if (strcmp(cp, "alias") == 0) {
#ifdef NONAT
log_Printf(LogWARN, "%s ignored: NAT is compiled out\n", argv[arg]);
fprintf(stderr, "%s ignored: NAT is compiled out\n", argv[arg]);
#else
log_Printf(LogWARN, "%s is deprecated\n", argv[arg]);
fprintf(stderr, "%s is deprecated\n", argv[arg]);
sw->nat = 1;
#endif
optc--; /* this option isn't exclusive */
} else if (strncmp(cp, "unit", 4) == 0) {
optc--; /* this option isn't exclusive */
if (cp[4] == '\0') {
optc--; /* nor is the argument */
if (++arg == argc) {
fprintf(stderr, "-unit: Expected unit number\n");
Usage();
} else
sw->unit = atoi(argv[arg]);
} else
sw->unit = atoi(cp + 4);
} else if (strcmp(cp, "quiet") == 0) {
sw->quiet = 1;
optc--; /* this option isn't exclusive */
} else
Usage();
break;
case PHYS_ALL:
Usage();
break;
default:
sw->mode = newmode;
if (newmode == PHYS_FOREGROUND)
sw->fg = 1;
}
}
if (optc > 1) {
fprintf(stderr, "You may specify only one mode.\n");
exit(EX_START);
}
if (sw->mode == PHYS_AUTO && arg == argc) {
fprintf(stderr, "A system must be specified in auto mode.\n");
exit(EX_START);
}
return arg; /* Don't SetLabel yet ! */
}
static void
CheckLabel(const char *label, struct prompt *prompt, int mode)
{
const char *err;
if ((err = system_IsValid(label, prompt, mode)) != NULL) {
fprintf(stderr, "%s: %s\n", label, err);
if (mode == PHYS_DIRECT)
log_Printf(LogWARN, "Label %s rejected -direct connection: %s\n",
label, err);
log_Close();
exit(1);
}
}
int
main(int argc, char **argv)
{
char *name;
const char *lastlabel;
int arg, holdfd[3], label;
unsigned f;
struct bundle *bundle;
struct prompt *prompt;
struct switches sw;
probe_Init();
/*
* We open 3 descriptors to ensure that STDIN_FILENO, STDOUT_FILENO and
* STDERR_FILENO are always open. These are closed before DoLoop(),
* but *after* we've avoided the possibility of erroneously closing
* an important descriptor with close(STD{IN,OUT,ERR}_FILENO).
*/
if ((holdfd[0] = open(_PATH_DEVNULL, O_RDWR)) == -1) {
fprintf(stderr, "Cannot open %s !\n", _PATH_DEVNULL);
return 2;
}
for (f = 1; f < sizeof holdfd / sizeof *holdfd; f++)
holdfd[f] = dup(holdfd[0]);
name = strrchr(argv[0], '/');
log_Open(name ? name + 1 : argv[0]);
#ifndef NONAT
la = LibAliasInit(NULL);
#endif
label = ProcessArgs(argc, argv, &sw);
/*
* A FreeBSD & OpenBSD hack to dodge a bug in the tty driver that drops
* output occasionally.... I must find the real reason some time. To
* display the dodgy behaviour, comment out this bit, make yourself a large
* routing table and then run ppp in interactive mode. The `show route'
* command will drop chunks of data !!!
*/
if (sw.mode == PHYS_INTERACTIVE) {
close(STDIN_FILENO);
if (open(_PATH_TTY, O_RDONLY) != STDIN_FILENO) {
fprintf(stderr, "Cannot open %s for input !\n", _PATH_TTY);
return 2;
}
}
/* Allow output for the moment (except in direct mode) */
if (sw.mode == PHYS_DIRECT)
prompt = NULL;
else
SignalPrompt = prompt = prompt_Create(NULL, NULL, PROMPT_STD);
ID0init();
if (ID0realuid() != 0) {
char conf[200], *ptr;
snprintf(conf, sizeof conf, "%s/%s", PPP_CONFDIR, CONFFILE);
do {
struct stat sb;
if (stat(conf, &sb) == 0 && sb.st_mode & S_IWOTH) {
log_Printf(LogALERT, "ppp: Access violation: Please protect %s\n",
conf);
return -1;
}
ptr = conf + strlen(conf)-2;
while (ptr > conf && *ptr != '/')
*ptr-- = '\0';
} while (ptr >= conf);
}
if (label < argc)
for (arg = label; arg < argc; arg++)
CheckLabel(argv[arg], prompt, sw.mode);
else
CheckLabel("default", prompt, sw.mode);
if (!sw.quiet)
prompt_Printf(prompt, "Working in %s mode\n", mode2Nam(sw.mode));
if ((bundle = bundle_Create(TUN_PREFIX, sw.mode, sw.unit)) == NULL)
return EX_START;
/* NOTE: We may now have changed argv[1] via a ``set proctitle'' */
SignalBundle = bundle;
bundle->NatEnabled = sw.nat;
if (sw.nat)
opt_enable(bundle, OPT_IFACEALIAS);
if (system_Select(bundle, "default", CONFFILE, prompt, NULL) < 0)
prompt_Printf(prompt, "Warning: No default entry found in config file.\n");
sig_signal(SIGHUP, CloseSession);
sig_signal(SIGTERM, CloseSession);
sig_signal(SIGINT, CloseConnection);
sig_signal(SIGQUIT, CloseSession);
sig_signal(SIGALRM, SIG_IGN);
signal(SIGPIPE, SIG_IGN);
if (sw.mode == PHYS_INTERACTIVE)
sig_signal(SIGTSTP, TerminalStop);
sig_signal(SIGUSR1, RestartServer);
sig_signal(SIGUSR2, BringDownServer);
lastlabel = argv[argc - 1];
for (arg = label; arg < argc; arg++) {
/* In case we use LABEL or ``set enddisc label'' */
bundle_SetLabel(bundle, lastlabel);
system_Select(bundle, argv[arg], CONFFILE, prompt, NULL);
}
if (label < argc)
/* In case the last label did a ``load'' */
bundle_SetLabel(bundle, lastlabel);
if (sw.mode == PHYS_AUTO &&
ncprange_family(&bundle->ncp.ipcp.cfg.peer_range) == AF_UNSPEC) {
prompt_Printf(prompt, "You must ``set ifaddr'' with a peer address "
"in auto mode.\n");
AbortProgram(EX_START);
}
if (prompt) {
prompt->bundle = bundle; /* couldn't do it earlier */
if (!sw.quiet)
prompt_Printf(prompt, "Using interface: %s\n", bundle->iface->name);
}
if (sw.mode != PHYS_INTERACTIVE) {
if (sw.mode != PHYS_DIRECT) {
if (!sw.fg) {
int bgpipe[2];
pid_t bgpid;
if (sw.mode == PHYS_BACKGROUND && pipe(bgpipe)) {
log_Printf(LogERROR, "pipe: %s\n", strerror(errno));
AbortProgram(EX_SOCK);
}
bgpid = fork();
if (bgpid == -1) {
log_Printf(LogERROR, "fork: %s\n", strerror(errno));
AbortProgram(EX_SOCK);
}
if (bgpid) {
char c = EX_NORMAL;
int ret;
if (sw.mode == PHYS_BACKGROUND) {
close(bgpipe[1]);
BGPid = bgpid;
/* If we get a signal, kill the child */
signal(SIGHUP, KillChild);
signal(SIGTERM, KillChild);
signal(SIGINT, KillChild);
signal(SIGQUIT, KillChild);
/* Wait for our child to close its pipe before we exit */
while ((ret = read(bgpipe[0], &c, 1)) == 1) {
switch (c) {
case EX_NORMAL:
if (!sw.quiet) {
prompt_Printf(prompt, "PPP enabled\n");
log_Printf(LogPHASE, "Parent: PPP enabled\n");
}
break;
case EX_REDIAL:
if (!sw.quiet)
prompt_Printf(prompt, "Attempting redial\n");
continue;
case EX_RECONNECT:
if (!sw.quiet)
prompt_Printf(prompt, "Attempting reconnect\n");
continue;
default:
prompt_Printf(prompt, "Child failed (%s)\n",
ex_desc((int)c));
log_Printf(LogPHASE, "Parent: Child failed (%s)\n",
ex_desc((int) c));
}
break;
}
if (ret != 1) {
prompt_Printf(prompt, "Child exit, no status.\n");
log_Printf(LogPHASE, "Parent: Child exit, no status.\n");
}
close(bgpipe[0]);
}
return c;
} else if (sw.mode == PHYS_BACKGROUND) {
close(bgpipe[0]);
bundle->notify.fd = bgpipe[1];
}
bundle_ChangedPID(bundle);
bundle_LockTun(bundle); /* we have a new pid */
}
/* -auto, -dedicated, -ddial, -foreground & -background */
prompt_Destroy(prompt, 0);
close(STDOUT_FILENO);
close(STDERR_FILENO);
close(STDIN_FILENO);
if (!sw.fg)
setsid();
} else {
/*
* -direct - STDIN_FILENO gets used by physical_Open. STDOUT_FILENO
* *may* get used in exec/pipe mode.
*/
prompt_TtyInit(NULL);
close(STDERR_FILENO);
}
} else {
/* -interactive */
close(STDERR_FILENO);
prompt_TtyInit(prompt);
prompt_TtyCommandMode(prompt);
prompt_Required(prompt);
}
/* We can get rid of these now */
for (f = 0; f < sizeof holdfd / sizeof *holdfd; f++)
close(holdfd[f]);
log_Printf(LogPHASE, "PPP Started (%s mode).\n", mode2Nam(sw.mode));
DoLoop(bundle);
AbortProgram(EX_NORMAL);
return EX_NORMAL;
}
static void
DoLoop(struct bundle *bundle)
{
fd_set *rfds, *wfds, *efds;
int i, nfds, nothing_done;
if ((rfds = mkfdset()) == NULL) {
log_Printf(LogERROR, "DoLoop: Cannot create fd_set\n");
return;
}
if ((wfds = mkfdset()) == NULL) {
log_Printf(LogERROR, "DoLoop: Cannot create fd_set\n");
free(rfds);
return;
}
if ((efds = mkfdset()) == NULL) {
log_Printf(LogERROR, "DoLoop: Cannot create fd_set\n");
free(rfds);
free(wfds);
return;
}
for (; !bundle_IsDead(bundle); bundle_CleanDatalinks(bundle)) {
nfds = 0;
zerofdset(rfds);
zerofdset(wfds);
zerofdset(efds);
/* All our datalinks, the tun device and the MP socket */
descriptor_UpdateSet(&bundle->desc, rfds, wfds, efds, &nfds);
/* All our prompts and the diagnostic socket */
descriptor_UpdateSet(&server.desc, rfds, NULL, NULL, &nfds);
bundle_CleanDatalinks(bundle);
if (bundle_IsDead(bundle))
/* Don't select - we'll be here forever */
break;
/*
* It's possible that we've had a signal since we last checked. If
* we don't check again before calling select(), we may end up stuck
* after having missed the event.... sig_Handle() tries to be as
* quick as possible if nothing is likely to have happened.
* This is only really likely if we block in open(... O_NONBLOCK)
* which will happen with a misconfigured device.
*/
if (sig_Handle())
continue;
i = select(nfds, rfds, wfds, efds, NULL);
if (i < 0 && errno != EINTR) {
log_Printf(LogERROR, "DoLoop: select(): %s\n", strerror(errno));
if (log_IsKept(LogTIMER)) {
struct timeval t;
for (i = 0; i <= nfds; i++) {
if (FD_ISSET(i, rfds)) {
log_Printf(LogTIMER, "Read set contains %d\n", i);
FD_CLR(i, rfds);
t.tv_sec = t.tv_usec = 0;
if (select(nfds, rfds, wfds, efds, &t) != -1) {
log_Printf(LogTIMER, "The culprit !\n");
break;
}
}
if (FD_ISSET(i, wfds)) {
log_Printf(LogTIMER, "Write set contains %d\n", i);
FD_CLR(i, wfds);
t.tv_sec = t.tv_usec = 0;
if (select(nfds, rfds, wfds, efds, &t) != -1) {
log_Printf(LogTIMER, "The culprit !\n");
break;
}
}
if (FD_ISSET(i, efds)) {
log_Printf(LogTIMER, "Error set contains %d\n", i);
FD_CLR(i, efds);
t.tv_sec = t.tv_usec = 0;
if (select(nfds, rfds, wfds, efds, &t) != -1) {
log_Printf(LogTIMER, "The culprit !\n");
break;
}
}
}
}
break;
}
log_Printf(LogTIMER, "Select returns %d\n", i);
sig_Handle();
if (i <= 0)
continue;
for (i = 0; i <= nfds; i++)
if (FD_ISSET(i, efds)) {
log_Printf(LogPHASE, "Exception detected on descriptor %d\n", i);
/* We deal gracefully with link descriptor exceptions */
if (!bundle_Exception(bundle, i)) {
log_Printf(LogERROR, "Exception cannot be handled !\n");
break;
}
}
if (i <= nfds)
break;
nothing_done = 1;
if (descriptor_IsSet(&server.desc, rfds)) {
descriptor_Read(&server.desc, bundle, rfds);
nothing_done = 0;
}
if (descriptor_IsSet(&bundle->desc, rfds)) {
descriptor_Read(&bundle->desc, bundle, rfds);
nothing_done = 0;
}
if (descriptor_IsSet(&bundle->desc, wfds))
if (descriptor_Write(&bundle->desc, bundle, wfds) <= 0 && nothing_done) {
/*
* This is disastrous. The OS has told us that something is
* writable, and all our write()s have failed. Rather than
* going back immediately to do our UpdateSet()s and select(),
* we sleep for a bit to avoid gobbling up all cpu time.
*/
struct timeval t;
t.tv_sec = 0;
t.tv_usec = 100000;
select(0, NULL, NULL, NULL, &t);
}
}
log_Printf(LogDEBUG, "DoLoop done.\n");
}
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