const char *
system_IsValid(const char *name, struct prompt *prompt, int mode)
{
/*
* Note: The ReadSystem() calls only result in calls to the Allow*
* functions. arg->bundle will be set to NULL for these commands !
*/
int def, how, rs;
int defuserok;
def = !strcmp(name, "default");
how = ID0realuid() == 0 ? SYSTEM_EXISTS : SYSTEM_VALIDATE;
userok = -1;
modeok = 1;
modereq = mode;
rs = ReadSystem(NULL, "default", CONFFILE, prompt, NULL, how);
defuserok = userok;
userok = -1;
if (!def) {
if (rs == -1)
rs = 0; /* we don't care that ``default'' doesn't exist */
if (rs == 0)
rs = ReadSystem(NULL, name, CONFFILE, prompt, NULL, how);
if (rs == -1)
return "Configuration label not found";
if (rs == -2)
return PPP_CONFDIR "/" CONFFILE " : File not found";
}
if (userok == -1)
userok = defuserok;
if (how == SYSTEM_EXISTS)
userok = modeok = 1;
if (!userok)
return "User access denied";
if (!modeok)
return "Mode denied for this label";
return NULL;
}
int
AllowUsers(struct cmdargs const *arg)
{
/* arg->bundle may be NULL (see system_IsValid()) ! */
int f;
struct passwd *pwd;
if (userok == -1)
userok = 0;
pwd = getpwuid(ID0realuid());
if (pwd != NULL)
for (f = arg->argn; f < arg->argc; f++)
if (!strcmp("*", arg->argv[f]) || !strcmp(pwd->pw_name, arg->argv[f])) {
userok = 1;
break;
}
endpwent();
return 0;
}
static void
chap_StartChild(struct chap *chap, char *prog, const char *name)
{
char *argv[MAXARGS], *nargv[MAXARGS];
int argc, fd;
int in[2], out[2];
pid_t pid;
if (chap->child.fd != -1) {
log_Printf(LogWARN, "Chap: %s: Program already running\n", prog);
return;
}
if (pipe(in) == -1) {
log_Printf(LogERROR, "Chap: pipe: %s\n", strerror(errno));
return;
}
if (pipe(out) == -1) {
log_Printf(LogERROR, "Chap: pipe: %s\n", strerror(errno));
close(in[0]);
close(in[1]);
return;
}
pid = getpid();
switch ((chap->child.pid = fork())) {
case -1:
log_Printf(LogERROR, "Chap: fork: %s\n", strerror(errno));
close(in[0]);
close(in[1]);
close(out[0]);
close(out[1]);
chap->child.pid = 0;
return;
case 0:
timer_TermService();
if ((argc = command_Interpret(prog, strlen(prog), argv)) <= 0) {
if (argc < 0) {
log_Printf(LogWARN, "CHAP: Invalid command syntax\n");
_exit(255);
}
_exit(0);
}
close(in[1]);
close(out[0]);
if (out[1] == STDIN_FILENO)
out[1] = dup(out[1]);
dup2(in[0], STDIN_FILENO);
dup2(out[1], STDOUT_FILENO);
close(STDERR_FILENO);
if (open(_PATH_DEVNULL, O_RDWR) != STDERR_FILENO) {
log_Printf(LogALERT, "Chap: Failed to open %s: %s\n",
_PATH_DEVNULL, strerror(errno));
exit(1);
}
for (fd = getdtablesize(); fd > STDERR_FILENO; fd--)
fcntl(fd, F_SETFD, 1);
#ifndef NOSUID
setuid(ID0realuid());
#endif
command_Expand(nargv, argc, (char const *const *)argv,
chap->auth.physical->dl->bundle, 0, pid);
execvp(nargv[0], nargv);
printf("exec() of %s failed: %s\n", nargv[0], strerror(errno));
_exit(255);
default:
close(in[0]);
close(out[1]);
chap->child.fd = out[0];
chap->child.buf.len = 0;
write(in[1], chap->auth.in.name, strlen(chap->auth.in.name));
write(in[1], "\n", 1);
write(in[1], chap->challenge.peer + 1, *chap->challenge.peer);
write(in[1], "\n", 1);
write(in[1], name, strlen(name));
write(in[1], "\n", 1);
close(in[1]);
break;
}
}
int
main(int argc, char **argv)
{
char *name;
const char *lastlabel;
int arg, f, holdfd[3], label;
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
PacketAliasInit();
#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'' */
if (prompt) {
prompt->bundle = bundle; /* couldn't do it earlier */
if (!sw.quiet)
prompt_Printf(prompt, "Using interface: %s\n", bundle->iface->name);
}
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 (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 */
prompt_TtyInit(NULL);
close(STDOUT_FILENO);
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;
}
/*
* Move string from ``from'' to ``to'', interpreting ``~'' and $....
* Returns NULL if string expansion failed due to lack of buffer space.
*/
const char *
InterpretArg(const char *from, char *to, size_t tosiz)
{
char *ptr, *startto, *endto;
struct passwd *pwd;
int len, instring;
const char *env;
instring = 0;
startto = to;
endto = to + tosiz - 1;
while(issep(*from))
from++;
while (*from != '\0') {
if (to >= endto)
return NULL;
switch (*from) {
case '"':
instring = !instring;
*to++ = *from++;
break;
case '\\':
switch (*++from) {
case '$':
case '~':
break; /* Swallow the escapes */
default:
*to++ = '\\'; /* Pass the escapes on, maybe skipping \# */
break;
}
if (to >= endto)
return NULL;
*to++ = *from++;
break;
case '$':
if (from[1] == '$') {
*to = '\0'; /* For an empty var name below */
from += 2;
} else if (from[1] == '{') {
ptr = strchr(from+2, '}');
if (ptr) {
len = ptr - from - 2;
if (endto - to < len )
return NULL;
if (len) {
strncpy(to, from+2, len);
to[len] = '\0';
from = ptr+1;
} else {
*to++ = *from++;
continue;
}
} else {
*to++ = *from++;
continue;
}
} else {
ptr = to;
for (from++; (isalnum(*from) || *from == '_') && ptr < endto; from++)
*ptr++ = *from;
*ptr = '\0';
}
if (to >= endto)
return NULL;
if (*to == '\0')
*to++ = '$';
else if ((env = getenv(to)) != NULL) {
if (endto - to < strlen(env))
return NULL;
strncpy(to, env, endto - to);
*endto = '\0';
to += strlen(to);
}
break;
case '~':
ptr = strchr(++from, '/');
len = ptr ? ptr - from : strlen(from);
if (len == 0)
pwd = getpwuid(ID0realuid());
else {
if (endto - to < len)
return NULL;
strncpy(to, from, len);
to[len] = '\0';
pwd = getpwnam(to);
}
if (to >= endto)
return NULL;
if (pwd == NULL)
*to++ = '~';
else {
if (endto - to < strlen(pwd->pw_dir))
return NULL;
strncpy(to, pwd->pw_dir, endto - to);
*endto = '\0';
to += strlen(to);
from += len;
}
endpwent();
break;
default:
*to++ = *from++;
break;
}
}
while (to > startto) {
to--;
if (!issep(*to)) {
to++;
break;
}
}
*to = '\0';
return from;
}
struct device *
exec_Create(struct physical *p)
{
struct execdevice *dev;
dev = NULL;
if (p->fd < 0) {
if (*p->name.full == '!') {
int fids[2], type;
if ((dev = malloc(sizeof *dev)) == NULL) {
log_Printf(LogWARN, "%s: Cannot allocate an exec device: %s\n",
p->link.name, strerror(errno));
return NULL;
}
dev->fd_out = -1;
p->fd--; /* We own the device but maybe can't use it - change fd */
type = physical_IsSync(p) ? SOCK_DGRAM : SOCK_STREAM;
if (socketpair(AF_UNIX, type, PF_UNSPEC, fids) < 0) {
log_Printf(LogPHASE, "Unable to create pipe for line exec: %s\n",
strerror(errno));
free(dev);
dev = NULL;
} else {
static int child_status; /* This variable is abused ! */
int stat, argc, i, ret, wret, pidpipe[2];
pid_t pid, realpid;
char *argv[MAXARGS];
stat = fcntl(fids[0], F_GETFL, 0);
if (stat > 0) {
stat |= O_NONBLOCK;
fcntl(fids[0], F_SETFL, stat);
}
realpid = getpid();
if (pipe(pidpipe) == -1) {
log_Printf(LogPHASE, "Unable to pipe for line exec: %s\n",
strerror(errno));
close(fids[1]);
close(fids[0]);
free(dev);
dev = NULL;
} else switch ((pid = fork())) {
case -1:
log_Printf(LogPHASE, "Unable to fork for line exec: %s\n",
strerror(errno));
close(pidpipe[0]);
close(pidpipe[1]);
close(fids[1]);
close(fids[0]);
break;
case 0:
close(pidpipe[0]);
close(fids[0]);
timer_TermService();
#ifndef NOSUID
setuid(ID0realuid());
#endif
child_status = 0;
switch ((pid = vfork())) {
case 0:
close(pidpipe[1]);
break;
case -1:
ret = errno;
log_Printf(LogPHASE, "Unable to vfork to drop parent: %s\n",
strerror(errno));
close(pidpipe[1]);
_exit(ret);
default:
write(pidpipe[1], &pid, sizeof pid);
close(pidpipe[1]);
_exit(child_status); /* The error from exec() ! */
}
log_Printf(LogDEBUG, "Exec'ing ``%s''\n", p->name.base);
if ((argc = MakeArgs(p->name.base, argv, VECSIZE(argv),
PARSE_REDUCE|PARSE_NOHASH)) < 0) {
log_Printf(LogWARN, "Syntax error in exec command\n");
_exit(ESRCH);
}
command_Expand(argv, argc, (char const *const *)argv,
p->dl->bundle, 0, realpid);
dup2(fids[1], STDIN_FILENO);
dup2(fids[1], STDOUT_FILENO);
dup2(fids[1], STDERR_FILENO);
for (i = getdtablesize(); i > STDERR_FILENO; i--)
fcntl(i, F_SETFD, 1);
execvp(*argv, argv);
child_status = errno; /* Only works for vfork() */
printf("execvp failed: %s: %s\r\n", *argv, strerror(child_status));
_exit(child_status);
break;
default:
close(pidpipe[1]);
close(fids[1]);
if (read(pidpipe[0], &p->session_owner, sizeof p->session_owner) !=
sizeof p->session_owner)
p->session_owner = (pid_t)-1;
close(pidpipe[0]);
while ((wret = waitpid(pid, &stat, 0)) == -1 && errno == EINTR)
;
if (wret == -1) {
log_Printf(LogWARN, "Waiting for child process: %s\n",
strerror(errno));
close(fids[0]);
p->session_owner = (pid_t)-1;
break;
} else if (WIFSIGNALED(stat)) {
log_Printf(LogWARN, "Child process received sig %d !\n",
WTERMSIG(stat));
close(fids[0]);
p->session_owner = (pid_t)-1;
break;
} else if (WIFSTOPPED(stat)) {
log_Printf(LogWARN, "Child process received stop sig %d !\n",
WSTOPSIG(stat));
/* I guess that's ok.... */
} else if ((ret = WEXITSTATUS(stat))) {
log_Printf(LogWARN, "Cannot exec \"%s\": %s\n", p->name.base,
strerror(ret));
close(fids[0]);
p->session_owner = (pid_t)-1;
break;
}
p->fd = fids[0];
log_Printf(LogDEBUG, "Using descriptor %d for child\n", p->fd);
}
}
}
} else {
struct stat st;
if (fstat(p->fd, &st) != -1 && (st.st_mode & S_IFIFO)) {
if ((dev = malloc(sizeof *dev)) == NULL)
log_Printf(LogWARN, "%s: Cannot allocate an exec device: %s\n",
p->link.name, strerror(errno));
else if (p->fd == STDIN_FILENO) {
log_Printf(LogPHASE, "%s: Using stdin/stdout to communicate with "
"parent (pipe mode)\n", p->link.name);
dev->fd_out = dup(STDOUT_FILENO);
/* Hook things up so that we monitor dev->fd_out */
p->desc.UpdateSet = exec_UpdateSet;
p->desc.IsSet = exec_IsSet;
} else
dev->fd_out = -1;
}
}
if (dev) {
memcpy(&dev->dev, &baseexecdevice, sizeof dev->dev);
physical_SetupStack(p, dev->dev.name, PHYSICAL_NOFORCE);
if (p->cfg.cd.necessity != CD_DEFAULT)
log_Printf(LogWARN, "Carrier settings ignored\n");
return &dev->dev;
}
return NULL;
}
