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freebsd/usr.sbin/inetd/inetd.c
Garrett Wollman 71704f34b1 Disable UDP service looping attack.
1994-12-21 19:08:45 +00:00

1452 lines
35 KiB
C
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/*
* Copyright (c) 1983, 1991, 1993, 1994
* The Regents of the University of California. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
*/
#ifndef lint
static char copyright[] =
"@(#) Copyright (c) 1983, 1991, 1993, 1994\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
/* from: @(#)inetd.c 8.4 (Berkeley) 4/13/94"; */
static char inetd_c_rcsid[] =
"$Id$";
#endif /* not lint */
/*
* Inetd - Internet super-server
*
* This program invokes all internet services as needed. Connection-oriented
* services are invoked each time a connection is made, by creating a process.
* This process is passed the connection as file descriptor 0 and is expected
* to do a getpeername to find out the source host and port.
*
* Datagram oriented services are invoked when a datagram
* arrives; a process is created and passed a pending message
* on file descriptor 0. Datagram servers may either connect
* to their peer, freeing up the original socket for inetd
* to receive further messages on, or ``take over the socket'',
* processing all arriving datagrams and, eventually, timing
* out. The first type of server is said to be ``multi-threaded'';
* the second type of server ``single-threaded''.
*
* Inetd uses a configuration file which is read at startup
* and, possibly, at some later time in response to a hangup signal.
* The configuration file is ``free format'' with fields given in the
* order shown below. Continuation lines for an entry must being with
* a space or tab. All fields must be present in each entry.
*
* service name must be in /etc/services or must
* name a tcpmux service
* socket type stream/dgram/raw/rdm/seqpacket
* protocol must be in /etc/protocols
* wait/nowait single-threaded/multi-threaded
* user user to run daemon as
* server program full path name
* server program arguments maximum of MAXARGS (20)
*
* TCP services without official port numbers are handled with the
* RFC1078-based tcpmux internal service. Tcpmux listens on port 1 for
* requests. When a connection is made from a foreign host, the service
* requested is passed to tcpmux, which looks it up in the servtab list
* and returns the proper entry for the service. Tcpmux returns a
* negative reply if the service doesn't exist, otherwise the invoked
* server is expected to return the positive reply if the service type in
* inetd.conf file has the prefix "tcpmux/". If the service type has the
* prefix "tcpmux/+", tcpmux will return the positive reply for the
* process; this is for compatibility with older server code, and also
* allows you to invoke programs that use stdin/stdout without putting any
* special server code in them. Services that use tcpmux are "nowait"
* because they do not have a well-known port and hence cannot listen
* for new requests.
*
* For RPC services
* service name/version must be in /etc/rpc
* socket type stream/dgram/raw/rdm/seqpacket
* protocol must be in /etc/protocols
* wait/nowait single-threaded/multi-threaded
* user user to run daemon as
* server program full path name
* server program arguments maximum of MAXARGS
*
* Comment lines are indicated by a `#' in column 1.
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <rpc/rpc.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "pathnames.h"
#define TOOMANY 256 /* don't start more than TOOMANY */
#define CNT_INTVL 60 /* servers in CNT_INTVL sec. */
#define RETRYTIME (60*10) /* retry after bind or server fail */
#define SIGBLOCK (sigmask(SIGCHLD)|sigmask(SIGHUP)|sigmask(SIGALRM))
int debug = 0;
int log = 0;
int nsock, maxsock;
fd_set allsock;
int options;
int timingout;
int toomany = TOOMANY;
struct servent *sp;
struct rpcent *rpc;
struct servtab {
char *se_service; /* name of service */
int se_socktype; /* type of socket to use */
char *se_proto; /* protocol used */
short se_wait; /* single threaded server */
short se_checked; /* looked at during merge */
char *se_user; /* user name to run as */
struct biltin *se_bi; /* if built-in, description */
char *se_server; /* server program */
#define MAXARGV 20
char *se_argv[MAXARGV+1]; /* program arguments */
int se_fd; /* open descriptor */
int se_type; /* type */
struct sockaddr_in se_ctrladdr;/* bound address */
int se_rpc; /* ==1 if RPC service */
int se_rpc_prog; /* RPC program number */
u_int se_rpc_lowvers; /* RPC low version */
u_int se_rpc_highvers; /* RPC high version */
int se_count; /* number started since se_time */
struct timeval se_time; /* start of se_count */
struct servtab *se_next;
} *servtab;
#define NORM_TYPE 0
#define MUX_TYPE 1
#define MUXPLUS_TYPE 2
#define ISMUX(sep) (((sep)->se_type == MUX_TYPE) || \
((sep)->se_type == MUXPLUS_TYPE))
#define ISMUXPLUS(sep) ((sep)->se_type == MUXPLUS_TYPE)
void chargen_dg __P((int, struct servtab *));
void chargen_stream __P((int, struct servtab *));
void close_sep __P((struct servtab *));
void config __P((int));
void daytime_dg __P((int, struct servtab *));
void daytime_stream __P((int, struct servtab *));
void discard_dg __P((int, struct servtab *));
void discard_stream __P((int, struct servtab *));
void echo_dg __P((int, struct servtab *));
void echo_stream __P((int, struct servtab *));
void endconfig __P((void));
struct servtab *enter __P((struct servtab *));
void freeconfig __P((struct servtab *));
struct servtab *getconfigent __P((void));
void machtime_dg __P((int, struct servtab *));
void machtime_stream __P((int, struct servtab *));
char *newstr __P((char *));
char *nextline __P((FILE *));
void print_service __P((char *, struct servtab *));
void reapchild __P((int));
void retry __P((int));
int setconfig __P((void));
void setup __P((struct servtab *));
char *sskip __P((char **));
char *skip __P((char **));
struct servtab *tcpmux __P((int));
void unregisterrpc __P((register struct servtab *sep));
struct biltin {
char *bi_service; /* internally provided service name */
int bi_socktype; /* type of socket supported */
short bi_fork; /* 1 if should fork before call */
short bi_wait; /* 1 if should wait for child */
void (*bi_fn)(); /* function which performs it */
} biltins[] = {
/* Echo received data */
{ "echo", SOCK_STREAM, 1, 0, echo_stream },
{ "echo", SOCK_DGRAM, 0, 0, echo_dg },
/* Internet /dev/null */
{ "discard", SOCK_STREAM, 1, 0, discard_stream },
{ "discard", SOCK_DGRAM, 0, 0, discard_dg },
/* Return 32 bit time since 1970 */
{ "time", SOCK_STREAM, 0, 0, machtime_stream },
{ "time", SOCK_DGRAM, 0, 0, machtime_dg },
/* Return human-readable time */
{ "daytime", SOCK_STREAM, 0, 0, daytime_stream },
{ "daytime", SOCK_DGRAM, 0, 0, daytime_dg },
/* Familiar character generator */
{ "chargen", SOCK_STREAM, 1, 0, chargen_stream },
{ "chargen", SOCK_DGRAM, 0, 0, chargen_dg },
{ "tcpmux", SOCK_STREAM, 1, 0, (void (*)())tcpmux },
{ NULL }
};
#define NUMINT (sizeof(intab) / sizeof(struct inent))
char *CONFIG = _PATH_INETDCONF;
char **Argv;
char *LastArg;
int
main(argc, argv, envp)
int argc;
char *argv[], *envp[];
{
struct servtab *sep;
struct passwd *pwd;
struct sigvec sv;
int tmpint, ch, dofork;
pid_t pid;
char buf[50];
struct sockaddr_in peer;
int i;
Argv = argv;
if (envp == 0 || *envp == 0)
envp = argv;
while (*envp)
envp++;
LastArg = envp[-1] + strlen(envp[-1]);
openlog("inetd", LOG_PID | LOG_NOWAIT, LOG_DAEMON);
while ((ch = getopt(argc, argv, "dlR:")) != EOF)
switch(ch) {
case 'd':
debug = 1;
options |= SO_DEBUG;
break;
case 'l':
log = 1;
break;
case 'R': { /* invocation rate */
char *p;
tmpint = strtol(optarg, &p, 0);
if (tmpint < 1 || *p)
syslog(LOG_ERR,
"-R %s: bad value for service invocation rate",
optarg);
else
toomany = tmpint;
break;
}
case '?':
default:
syslog(LOG_ERR,
"usage: inetd [-dl] [-R rate] [conf-file]");
exit(1);
}
argc -= optind;
argv += optind;
if (argc > 0)
CONFIG = argv[0];
if (debug == 0) {
daemon(0, 0);
}
memset(&sv, 0, sizeof(sv));
sv.sv_mask = SIGBLOCK;
sv.sv_handler = retry;
sigvec(SIGALRM, &sv, (struct sigvec *)0);
config(SIGHUP);
sv.sv_handler = config;
sigvec(SIGHUP, &sv, (struct sigvec *)0);
sv.sv_handler = reapchild;
sigvec(SIGCHLD, &sv, (struct sigvec *)0);
{
/* space for daemons to overwrite environment for ps */
#define DUMMYSIZE 100
char dummy[DUMMYSIZE];
(void)memset(dummy, 'x', sizeof(DUMMYSIZE) - 1);
dummy[DUMMYSIZE - 1] = '\0';
(void)setenv("inetd_dummy", dummy, 1);
}
for (;;) {
int n, ctrl;
fd_set readable;
if (nsock == 0) {
(void) sigblock(SIGBLOCK);
while (nsock == 0)
sigpause(0L);
(void) sigsetmask(0L);
}
readable = allsock;
if ((n = select(maxsock + 1, &readable, (fd_set *)0,
(fd_set *)0, (struct timeval *)0)) <= 0) {
if (n < 0 && errno != EINTR)
syslog(LOG_WARNING, "select: %m");
sleep(1);
continue;
}
for (sep = servtab; n && sep; sep = sep->se_next)
if (sep->se_fd != -1 && FD_ISSET(sep->se_fd, &readable)) {
n--;
if (debug)
fprintf(stderr, "someone wants %s\n",
sep->se_service);
if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
ctrl = accept(sep->se_fd, (struct sockaddr *)0,
(int *)0);
if (debug)
fprintf(stderr, "accept, ctrl %d\n", ctrl);
if (ctrl < 0) {
if (errno != EINTR)
syslog(LOG_WARNING,
"accept (for %s): %m",
sep->se_service);
continue;
}
if(log) {
i = sizeof peer;
if(getpeername(ctrl, (struct sockaddr *)
&peer, &i)) {
syslog(LOG_WARNING,
"getpeername(for %s): %m",
sep->se_service);
continue;
}
syslog(LOG_INFO,"%s from %s",
sep->se_service,
inet_ntoa(peer.sin_addr));
}
/*
* Call tcpmux to find the real service to exec.
*/
if (sep->se_bi &&
sep->se_bi->bi_fn == (void (*)()) tcpmux) {
sep = tcpmux(ctrl);
if (sep == NULL) {
close(ctrl);
continue;
}
}
} else
ctrl = sep->se_fd;
(void) sigblock(SIGBLOCK);
pid = 0;
dofork = (sep->se_bi == 0 || sep->se_bi->bi_fork);
if (dofork) {
if (sep->se_count++ == 0)
(void)gettimeofday(&sep->se_time,
(struct timezone *)0);
else if (sep->se_count >= toomany) {
struct timeval now;
(void)gettimeofday(&now, (struct timezone *)0);
if (now.tv_sec - sep->se_time.tv_sec >
CNT_INTVL) {
sep->se_time = now;
sep->se_count = 1;
} else {
syslog(LOG_ERR,
"%s/%s server failing (looping), service terminated",
sep->se_service, sep->se_proto);
close_sep(sep);
sigsetmask(0L);
if (!timingout) {
timingout = 1;
alarm(RETRYTIME);
}
continue;
}
}
pid = fork();
}
if (pid < 0) {
syslog(LOG_ERR, "fork: %m");
if (!sep->se_wait &&
sep->se_socktype == SOCK_STREAM)
close(ctrl);
sigsetmask(0L);
sleep(1);
continue;
}
if (pid && sep->se_wait) {
sep->se_wait = pid;
if (sep->se_fd >= 0) {
FD_CLR(sep->se_fd, &allsock);
nsock--;
}
}
sigsetmask(0L);
if (pid == 0) {
if (debug && dofork)
setsid();
if (dofork) {
if (debug)
fprintf(stderr, "+ Closing from %d\n",
maxsock);
for (tmpint = maxsock; tmpint > 2; tmpint--)
if (tmpint != ctrl)
close(tmpint);
}
if (sep->se_bi)
(*sep->se_bi->bi_fn)(ctrl, sep);
else {
if (debug)
fprintf(stderr, "%d execl %s\n",
getpid(), sep->se_server);
dup2(ctrl, 0);
close(ctrl);
dup2(0, 1);
dup2(0, 2);
if ((pwd = getpwnam(sep->se_user)) == NULL) {
syslog(LOG_ERR,
"%s/%s: %s: No such user",
sep->se_service, sep->se_proto,
sep->se_user);
if (sep->se_socktype != SOCK_STREAM)
recv(0, buf, sizeof (buf), 0);
_exit(1);
}
if (pwd->pw_uid) {
if (setgid(pwd->pw_gid) < 0) {
syslog(LOG_ERR,
"%s: can't set gid %d: %m",
sep->se_service, pwd->pw_gid);
_exit(1);
}
(void) initgroups(pwd->pw_name,
pwd->pw_gid);
if (setuid(pwd->pw_uid) < 0) {
syslog(LOG_ERR,
"%s: can't set uid %d: %m",
sep->se_service, pwd->pw_uid);
_exit(1);
}
}
execv(sep->se_server, sep->se_argv);
if (sep->se_socktype != SOCK_STREAM)
recv(0, buf, sizeof (buf), 0);
syslog(LOG_ERR,
"cannot execute %s: %m", sep->se_server);
_exit(1);
}
}
if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
close(ctrl);
}
}
}
void
reapchild(signo)
int signo;
{
int status;
pid_t pid;
struct servtab *sep;
for (;;) {
pid = wait3(&status, WNOHANG, (struct rusage *)0);
if (pid <= 0)
break;
if (debug)
fprintf(stderr, "%d reaped, status %#x\n",
pid, status);
for (sep = servtab; sep; sep = sep->se_next)
if (sep->se_wait == pid) {
if (status)
syslog(LOG_WARNING,
"%s: exit status 0x%x",
sep->se_server, status);
if (debug)
fprintf(stderr, "restored %s, fd %d\n",
sep->se_service, sep->se_fd);
FD_SET(sep->se_fd, &allsock);
nsock++;
sep->se_wait = 1;
}
}
}
void
config(signo)
int signo;
{
struct servtab *sep, *cp, **sepp;
struct passwd *pwd;
long omask;
if (!setconfig()) {
syslog(LOG_ERR, "%s: %m", CONFIG);
return;
}
for (sep = servtab; sep; sep = sep->se_next)
sep->se_checked = 0;
while (cp = getconfigent()) {
if ((pwd = getpwnam(cp->se_user)) == NULL) {
syslog(LOG_ERR,
"%s/%s: No such user '%s', service ignored",
cp->se_service, cp->se_proto, cp->se_user);
continue;
}
for (sep = servtab; sep; sep = sep->se_next)
if (strcmp(sep->se_service, cp->se_service) == 0 &&
strcmp(sep->se_proto, cp->se_proto) == 0)
break;
if (sep != 0) {
int i;
omask = sigblock(SIGBLOCK);
/*
* sep->se_wait may be holding the pid of a daemon
* that we're waiting for. If so, don't overwrite
* it unless the config file explicitly says don't
* wait.
*/
if (cp->se_bi == 0 &&
(sep->se_wait == 1 || cp->se_wait == 0))
sep->se_wait = cp->se_wait;
#define SWAP(a, b) { char *c = a; a = b; b = c; }
if (cp->se_user)
SWAP(sep->se_user, cp->se_user);
if (cp->se_server)
SWAP(sep->se_server, cp->se_server);
for (i = 0; i < MAXARGV; i++)
SWAP(sep->se_argv[i], cp->se_argv[i]);
sigsetmask(omask);
freeconfig(cp);
if (debug)
print_service("REDO", sep);
} else {
sep = enter(cp);
if (debug)
print_service("ADD ", sep);
}
sep->se_checked = 1;
if (ISMUX(sep)) {
sep->se_fd = -1;
continue;
}
if (!sep->se_rpc) {
sp = getservbyname(sep->se_service, sep->se_proto);
if (sp == 0) {
syslog(LOG_ERR, "%s/%s: unknown service",
sep->se_service, sep->se_proto);
sep->se_checked = 0;
continue;
}
if (sp->s_port != sep->se_ctrladdr.sin_port) {
sep->se_ctrladdr.sin_family = AF_INET;
sep->se_ctrladdr.sin_port = sp->s_port;
if (sep->se_fd >= 0)
close_sep(sep);
}
} else {
rpc = getrpcbyname(sep->se_service);
if (rpc == 0) {
syslog(LOG_ERR, "%s/%s unknown RPC service.",
sep->se_service, sep->se_proto);
if (sep->se_fd != -1)
(void) close(sep->se_fd);
sep->se_fd = -1;
continue;
}
if (rpc->r_number != sep->se_rpc_prog) {
if (sep->se_rpc_prog)
unregisterrpc(sep);
sep->se_rpc_prog = rpc->r_number;
if (sep->se_fd != -1)
(void) close(sep->se_fd);
sep->se_fd = -1;
}
}
if (sep->se_fd == -1)
setup(sep);
}
endconfig();
/*
* Purge anything not looked at above.
*/
omask = sigblock(SIGBLOCK);
sepp = &servtab;
while (sep = *sepp) {
if (sep->se_checked) {
sepp = &sep->se_next;
continue;
}
*sepp = sep->se_next;
if (sep->se_fd >= 0)
close_sep(sep);
if (debug)
print_service("FREE", sep);
if (sep->se_rpc && sep->se_rpc_prog > 0)
unregisterrpc(sep);
freeconfig(sep);
free((char *)sep);
}
(void) sigsetmask(omask);
}
void
unregisterrpc(sep)
struct servtab *sep;
{
int i;
struct servtab *sepp;
long omask;
omask = sigblock(SIGBLOCK);
for (sepp = servtab; sepp; sepp = sepp->se_next) {
if (sepp == sep)
continue;
if (sep->se_checked == 0 ||
!sepp->se_rpc ||
sep->se_rpc_prog != sepp->se_rpc_prog)
continue;
return;
}
if (debug)
print_service("UNREG", sep);
for (i = sep->se_rpc_lowvers; i <= sep->se_rpc_highvers; i++)
pmap_unset(sep->se_rpc_prog, i);
if (sep->se_fd != -1)
(void) close(sep->se_fd);
sep->se_fd = -1;
(void) sigsetmask(omask);
}
void
retry(signo)
int signo;
{
struct servtab *sep;
timingout = 0;
for (sep = servtab; sep; sep = sep->se_next)
if (sep->se_fd == -1)
setup(sep);
}
void
setup(sep)
struct servtab *sep;
{
int on = 1;
if ((sep->se_fd = socket(AF_INET, sep->se_socktype, 0)) < 0) {
if (debug)
fprintf(stderr, "socket failed on %s/%s: %s\n",
sep->se_service, sep->se_proto,
strerror(errno));
syslog(LOG_ERR, "%s/%s: socket: %m",
sep->se_service, sep->se_proto);
return;
}
#define turnon(fd, opt) \
setsockopt(fd, SOL_SOCKET, opt, (char *)&on, sizeof (on))
if (strcmp(sep->se_proto, "tcp") == 0 && (options & SO_DEBUG) &&
turnon(sep->se_fd, SO_DEBUG) < 0)
syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m");
if (turnon(sep->se_fd, SO_REUSEADDR) < 0)
syslog(LOG_ERR, "setsockopt (SO_REUSEADDR): %m");
#undef turnon
if (bind(sep->se_fd, (struct sockaddr *)&sep->se_ctrladdr,
sizeof (sep->se_ctrladdr)) < 0) {
if (debug)
fprintf(stderr, "bind failed on %s/%s: %s\n",
sep->se_service, sep->se_proto,
strerror(errno));
syslog(LOG_ERR, "%s/%s: bind: %m",
sep->se_service, sep->se_proto);
(void) close(sep->se_fd);
sep->se_fd = -1;
if (!timingout) {
timingout = 1;
alarm(RETRYTIME);
}
return;
}
if (sep->se_rpc) {
int i, len = sizeof(struct sockaddr);
if (getsockname(sep->se_fd,
(struct sockaddr*)&sep->se_ctrladdr, &len) < 0){
syslog(LOG_ERR, "%s/%s: getsockname: %m",
sep->se_service, sep->se_proto);
(void) close(sep->se_fd);
sep->se_fd = -1;
return;
}
if (debug)
print_service("REG ", sep);
for (i = sep->se_rpc_lowvers; i <= sep->se_rpc_highvers; i++) {
pmap_unset(sep->se_rpc_prog, i);
pmap_set(sep->se_rpc_prog, i,
(sep->se_socktype == SOCK_DGRAM)
? IPPROTO_UDP : IPPROTO_TCP,
ntohs(sep->se_ctrladdr.sin_port));
}
}
if (sep->se_socktype == SOCK_STREAM)
listen(sep->se_fd, 10);
FD_SET(sep->se_fd, &allsock);
nsock++;
if (sep->se_fd > maxsock)
maxsock = sep->se_fd;
if (debug) {
fprintf(stderr, "registered %s on %d\n",
sep->se_server, sep->se_fd);
}
}
/*
* Finish with a service and its socket.
*/
void
close_sep(sep)
struct servtab *sep;
{
if (sep->se_fd >= 0) {
nsock--;
FD_CLR(sep->se_fd, &allsock);
(void) close(sep->se_fd);
sep->se_fd = -1;
}
sep->se_count = 0;
/*
* Don't keep the pid of this running deamon: when reapchild()
* reaps this pid, it would erroneously increment nsock.
*/
if (sep->se_wait > 1)
sep->se_wait = 1;
}
struct servtab *
enter(cp)
struct servtab *cp;
{
struct servtab *sep;
long omask;
sep = (struct servtab *)malloc(sizeof (*sep));
if (sep == (struct servtab *)0) {
syslog(LOG_ERR, "Out of memory.");
exit(-1);
}
*sep = *cp;
sep->se_fd = -1;
omask = sigblock(SIGBLOCK);
sep->se_next = servtab;
servtab = sep;
sigsetmask(omask);
return (sep);
}
FILE *fconfig = NULL;
struct servtab serv;
char line[LINE_MAX];
int
setconfig()
{
if (fconfig != NULL) {
fseek(fconfig, 0L, SEEK_SET);
return (1);
}
fconfig = fopen(CONFIG, "r");
return (fconfig != NULL);
}
void
endconfig()
{
if (fconfig) {
(void) fclose(fconfig);
fconfig = NULL;
}
}
struct servtab *
getconfigent()
{
struct servtab *sep = &serv;
int argc;
char *cp, *arg;
char *versp;
static char TCPMUX_TOKEN[] = "tcpmux/";
#define MUX_LEN (sizeof(TCPMUX_TOKEN)-1)
more:
while ((cp = nextline(fconfig)) && (*cp == '#' || *cp == '\0'))
;
if (cp == NULL)
return ((struct servtab *)0);
/*
* clear the static buffer, since some fields (se_ctrladdr,
* for example) don't get initialized here.
*/
memset((caddr_t)sep, 0, sizeof *sep);
arg = skip(&cp);
if (cp == NULL) {
/* got an empty line containing just blanks/tabs. */
goto more;
}
if (strncmp(arg, TCPMUX_TOKEN, MUX_LEN) == 0) {
char *c = arg + MUX_LEN;
if (*c == '+') {
sep->se_type = MUXPLUS_TYPE;
c++;
} else
sep->se_type = MUX_TYPE;
sep->se_service = newstr(c);
} else {
sep->se_service = newstr(arg);
sep->se_type = NORM_TYPE;
}
arg = sskip(&cp);
if (strcmp(arg, "stream") == 0)
sep->se_socktype = SOCK_STREAM;
else if (strcmp(arg, "dgram") == 0)
sep->se_socktype = SOCK_DGRAM;
else if (strcmp(arg, "rdm") == 0)
sep->se_socktype = SOCK_RDM;
else if (strcmp(arg, "seqpacket") == 0)
sep->se_socktype = SOCK_SEQPACKET;
else if (strcmp(arg, "raw") == 0)
sep->se_socktype = SOCK_RAW;
else
sep->se_socktype = -1;
sep->se_proto = newstr(sskip(&cp));
if (strncmp(sep->se_proto, "rpc/", 4) == 0) {
sep->se_proto += 4;
sep->se_rpc = 1;
sep->se_rpc_prog = sep->se_rpc_lowvers =
sep->se_rpc_lowvers = 0;
sep->se_ctrladdr.sin_family = AF_INET;
sep->se_ctrladdr.sin_port = 0;
sep->se_ctrladdr.sin_addr.s_addr = htonl(INADDR_ANY);
if ((versp = rindex(sep->se_service, '/'))) {
*versp++ = '\0';
switch (sscanf(versp, "%d-%d",
&sep->se_rpc_lowvers,
&sep->se_rpc_highvers)) {
case 2:
break;
case 1:
sep->se_rpc_highvers =
sep->se_rpc_lowvers;
break;
default:
syslog(LOG_ERR,
"bad RPC version specifier; %s\n",
sep->se_service);
freeconfig(sep);
goto more;
}
}
else {
sep->se_rpc_lowvers =
sep->se_rpc_highvers = 1;
}
}
arg = sskip(&cp);
sep->se_wait = strcmp(arg, "wait") == 0;
if (ISMUX(sep)) {
/*
* Silently enforce "nowait" for TCPMUX services since
* they don't have an assigned port to listen on.
*/
sep->se_wait = 0;
if (strcmp(sep->se_proto, "tcp")) {
syslog(LOG_ERR,
"%s: bad protocol for tcpmux service %s",
CONFIG, sep->se_service);
goto more;
}
if (sep->se_socktype != SOCK_STREAM) {
syslog(LOG_ERR,
"%s: bad socket type for tcpmux service %s",
CONFIG, sep->se_service);
goto more;
}
}
sep->se_user = newstr(sskip(&cp));
sep->se_server = newstr(sskip(&cp));
if (strcmp(sep->se_server, "internal") == 0) {
struct biltin *bi;
for (bi = biltins; bi->bi_service; bi++)
if (bi->bi_socktype == sep->se_socktype &&
strcmp(bi->bi_service, sep->se_service) == 0)
break;
if (bi->bi_service == 0) {
syslog(LOG_ERR, "internal service %s unknown",
sep->se_service);
goto more;
}
sep->se_bi = bi;
sep->se_wait = bi->bi_wait;
} else
sep->se_bi = NULL;
argc = 0;
for (arg = skip(&cp); cp; arg = skip(&cp))
if (argc < MAXARGV)
sep->se_argv[argc++] = newstr(arg);
while (argc <= MAXARGV)
sep->se_argv[argc++] = NULL;
return (sep);
}
void
freeconfig(cp)
struct servtab *cp;
{
int i;
if (cp->se_service)
free(cp->se_service);
if (cp->se_proto)
free(cp->se_proto);
if (cp->se_user)
free(cp->se_user);
if (cp->se_server)
free(cp->se_server);
for (i = 0; i < MAXARGV; i++)
if (cp->se_argv[i])
free(cp->se_argv[i]);
}
/*
* Safe skip - if skip returns null, log a syntax error in the
* configuration file and exit.
*/
char *
sskip(cpp)
char **cpp;
{
char *cp;
cp = skip(cpp);
if (cp == NULL) {
syslog(LOG_ERR, "%s: syntax error", CONFIG);
exit(-1);
}
return (cp);
}
char *
skip(cpp)
char **cpp;
{
char *cp = *cpp;
char *start;
again:
while (*cp == ' ' || *cp == '\t')
cp++;
if (*cp == '\0') {
int c;
c = getc(fconfig);
(void) ungetc(c, fconfig);
if (c == ' ' || c == '\t')
if (cp = nextline(fconfig))
goto again;
*cpp = (char *)0;
return ((char *)0);
}
start = cp;
while (*cp && *cp != ' ' && *cp != '\t')
cp++;
if (*cp != '\0')
*cp++ = '\0';
*cpp = cp;
return (start);
}
char *
nextline(fd)
FILE *fd;
{
char *cp;
if (fgets(line, sizeof (line), fd) == NULL)
return ((char *)0);
cp = strchr(line, '\n');
if (cp)
*cp = '\0';
return (line);
}
char *
newstr(cp)
char *cp;
{
if (cp = strdup(cp ? cp : ""))
return (cp);
syslog(LOG_ERR, "strdup: %m");
exit(-1);
}
void
setproctitle(a, s)
char *a;
int s;
{
int size;
char *cp;
struct sockaddr_in sin;
char buf[80];
cp = Argv[0];
size = sizeof(sin);
if (getpeername(s, (struct sockaddr *)&sin, &size) == 0)
(void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sin.sin_addr));
else
(void) sprintf(buf, "-%s", a);
strncpy(cp, buf, LastArg - cp);
cp += strlen(cp);
while (cp < LastArg)
*cp++ = ' ';
}
/*
* Internet services provided internally by inetd:
*/
#define BUFSIZE 8192
/* ARGSUSED */
void
echo_stream(s, sep) /* Echo service -- echo data back */
int s;
struct servtab *sep;
{
char buffer[BUFSIZE];
int i;
setproctitle(sep->se_service, s);
while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
write(s, buffer, i) > 0)
;
exit(0);
}
int check_loop(sin, sep)
struct sockaddr_in *sin;
struct servtab *sep;
{
struct servtab *se2;
for (se2 = servtab; se2; se2 = se2->se_next) {
if (!se2->se_bi || se2->se_socktype != SOCK_DGRAM)
continue;
if (sin->sin_port == se2->se_ctrladdr.sin_port) {
syslog(LOG_WARNING,
"%s/%s:%s/%s loop request REFUSED from %s",
sep->se_service, sep->se_proto,
se2->se_service, se2->se_proto,
inet_ntoa(sin->sin_addr));
return 1;
}
}
return 0;
}
/* ARGSUSED */
void
echo_dg(s, sep) /* Echo service -- echo data back */
int s;
struct servtab *sep;
{
char buffer[BUFSIZE];
int i, size;
struct sockaddr_in sin;
size = sizeof(sin);
if ((i = recvfrom(s, buffer, sizeof(buffer), 0,
(struct sockaddr *)&sin, &size)) < 0)
return;
if (check_loop(&sin, sep))
return;
(void) sendto(s, buffer, i, 0, (struct sockaddr *)&sin,
sizeof(sin));
}
/* ARGSUSED */
void
discard_stream(s, sep) /* Discard service -- ignore data */
int s;
struct servtab *sep;
{
int ret;
char buffer[BUFSIZE];
setproctitle(sep->se_service, s);
while (1) {
while ((ret = read(s, buffer, sizeof(buffer))) > 0)
;
if (ret == 0 || errno != EINTR)
break;
}
exit(0);
}
/* ARGSUSED */
void
discard_dg(s, sep) /* Discard service -- ignore data */
int s;
struct servtab *sep;
{
char buffer[BUFSIZE];
(void) read(s, buffer, sizeof(buffer));
}
#include <ctype.h>
#define LINESIZ 72
char ring[128];
char *endring;
void
initring()
{
int i;
endring = ring;
for (i = 0; i <= 128; ++i)
if (isprint(i))
*endring++ = i;
}
/* ARGSUSED */
void
chargen_stream(s, sep) /* Character generator */
int s;
struct servtab *sep;
{
int len;
char *rs, text[LINESIZ+2];
setproctitle(sep->se_service, s);
if (!endring) {
initring();
rs = ring;
}
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
for (rs = ring;;) {
if ((len = endring - rs) >= LINESIZ)
memmove(text, rs, LINESIZ);
else {
memmove(text, rs, len);
memmove(text + len, ring, LINESIZ - len);
}
if (++rs == endring)
rs = ring;
if (write(s, text, sizeof(text)) != sizeof(text))
break;
}
exit(0);
}
/* ARGSUSED */
void
chargen_dg(s, sep) /* Character generator */
int s;
struct servtab *sep;
{
struct sockaddr_in sin;
static char *rs;
int len, size;
char text[LINESIZ+2];
if (endring == 0) {
initring();
rs = ring;
}
size = sizeof(sin);
if (recvfrom(s, text, sizeof(text), 0,
(struct sockaddr *)&sin, &size) < 0)
return;
if (check_loop(&sin, sep))
return;
if ((len = endring - rs) >= LINESIZ)
memmove(text, rs, LINESIZ);
else {
memmove(text, rs, len);
memmove(text + len, ring, LINESIZ - len);
}
if (++rs == endring)
rs = ring;
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
(void) sendto(s, text, sizeof(text), 0,
(struct sockaddr *)&sin, sizeof(sin));
}
/*
* Return a machine readable date and time, in the form of the
* number of seconds since midnight, Jan 1, 1900. Since gettimeofday
* returns the number of seconds since midnight, Jan 1, 1970,
* we must add 2208988800 seconds to this figure to make up for
* some seventy years Bell Labs was asleep.
*/
long
machtime()
{
struct timeval tv;
if (gettimeofday(&tv, (struct timezone *)0) < 0) {
if (debug)
fprintf(stderr, "Unable to get time of day\n");
return (0L);
}
#define OFFSET ((u_long)25567 * 24*60*60)
return (htonl((long)(tv.tv_sec + OFFSET)));
#undef OFFSET
}
/* ARGSUSED */
void
machtime_stream(s, sep)
int s;
struct servtab *sep;
{
long result;
result = machtime();
(void) write(s, (char *) &result, sizeof(result));
}
/* ARGSUSED */
void
machtime_dg(s, sep)
int s;
struct servtab *sep;
{
long result;
struct sockaddr_in sin;
int size;
size = sizeof(sin);
if (recvfrom(s, (char *)&result, sizeof(result), 0,
(struct sockaddr *)&sin, &size) < 0)
return;
if (check_loop(&sin, sep))
return;
result = machtime();
(void) sendto(s, (char *) &result, sizeof(result), 0,
(struct sockaddr *)&sin, sizeof(sin));
}
/* ARGSUSED */
void
daytime_stream(s, sep) /* Return human-readable time of day */
int s;
struct servtab *sep;
{
char buffer[256];
time_t clock;
clock = time((time_t *) 0);
(void) sprintf(buffer, "%.24s\r\n", ctime(&clock));
(void) write(s, buffer, strlen(buffer));
}
/* ARGSUSED */
void
daytime_dg(s, sep) /* Return human-readable time of day */
int s;
struct servtab *sep;
{
char buffer[256];
time_t clock;
struct sockaddr_in sin;
int size;
clock = time((time_t *) 0);
size = sizeof(sin);
if (recvfrom(s, buffer, sizeof(buffer), 0,
(struct sockaddr *)&sin, &size) < 0)
return;
if (check_loop(&sin, sep))
return;
(void) sprintf(buffer, "%.24s\r\n", ctime(&clock));
(void) sendto(s, buffer, strlen(buffer), 0,
(struct sockaddr *)&sin, sizeof(sin));
}
/*
* print_service:
* Dump relevant information to stderr
*/
void
print_service(action, sep)
char *action;
struct servtab *sep;
{
if(sep->se_rpc)
fprintf(stderr,
"%s: %s proto=%s, wait=%d, user=%s builtin=%x server=%s\n",
action, sep->se_service, sep->se_proto,
sep->se_wait, sep->se_user, (int)sep->se_bi,
sep->se_server);
else
fprintf(stderr,
"%s: %s proto=%s, wait=%d, user=%s builtin=%x server=%s\n",
action, sep->se_service, sep->se_proto,
sep->se_wait, sep->se_user, (int)sep->se_bi,
sep->se_server);
}
/*
* Based on TCPMUX.C by Mark K. Lottor November 1988
* sri-nic::ps:<mkl>tcpmux.c
*/
static int /* # of characters upto \r,\n or \0 */
getline(fd, buf, len)
int fd;
char *buf;
int len;
{
int count = 0, n;
do {
n = read(fd, buf, len-count);
if (n == 0)
return (count);
if (n < 0)
return (-1);
while (--n >= 0) {
if (*buf == '\r' || *buf == '\n' || *buf == '\0')
return (count);
count++;
buf++;
}
} while (count < len);
return (count);
}
#define MAX_SERV_LEN (256+2) /* 2 bytes for \r\n */
#define strwrite(fd, buf) (void) write(fd, buf, sizeof(buf)-1)
struct servtab *
tcpmux(s)
int s;
{
struct servtab *sep;
char service[MAX_SERV_LEN+1];
int len;
/* Get requested service name */
if ((len = getline(s, service, MAX_SERV_LEN)) < 0) {
strwrite(s, "-Error reading service name\r\n");
return (NULL);
}
service[len] = '\0';
if (debug)
fprintf(stderr, "tcpmux: someone wants %s\n", service);
/*
* Help is a required command, and lists available services,
* one per line.
*/
if (!strcasecmp(service, "help")) {
for (sep = servtab; sep; sep = sep->se_next) {
if (!ISMUX(sep))
continue;
(void)write(s,sep->se_service,strlen(sep->se_service));
strwrite(s, "\r\n");
}
return (NULL);
}
/* Try matching a service in inetd.conf with the request */
for (sep = servtab; sep; sep = sep->se_next) {
if (!ISMUX(sep))
continue;
if (!strcasecmp(service, sep->se_service)) {
if (ISMUXPLUS(sep)) {
strwrite(s, "+Go\r\n");
}
return (sep);
}
}
strwrite(s, "-Service not available\r\n");
return (NULL);
}
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