/* -*-c-*-
*
- * $Id: fw.c,v 1.4 1999/10/10 16:46:12 mdw Exp $
+ * $Id: fw.c,v 1.15 2003/11/25 14:46:50 mdw Exp $
*
* Port forwarding thingy
*
/*----- Revision history --------------------------------------------------*
*
* $Log: fw.c,v $
+ * Revision 1.15 2003/11/25 14:46:50 mdw
+ * Update docco for new options.
+ *
+ * Revision 1.14 2003/01/24 20:12:40 mdw
+ * Correctly cast uid and gid sentinel values.
+ *
+ * Revision 1.13 2002/02/22 23:45:20 mdw
+ * Add option to change the listen(2) parameter. Receive `fw'-specific
+ * code from `conf.c'.
+ *
+ * Revision 1.12 2002/01/13 14:49:17 mdw
+ * Track @dstr_vputf@ change.
+ *
+ * Revision 1.11 2001/02/03 20:33:26 mdw
+ * Fix flags to be unsigned.
+ *
+ * Revision 1.10 2001/02/03 20:30:03 mdw
+ * Support re-reading config files on SIGHUP.
+ *
+ * Revision 1.9 2001/01/20 11:55:17 mdw
+ * Handle select errors more robustly.
+ *
+ * Revision 1.8 2000/03/23 23:19:19 mdw
+ * Fix changed options in parser table.
+ *
+ * Revision 1.7 2000/03/23 00:37:33 mdw
+ * Add option to change user and group after initialization. Naughtily
+ * reassign short equivalents of --grammar and --options.
+ *
+ * Revision 1.6 1999/12/22 15:44:10 mdw
+ * Make syslog a separate option, and do it better.
+ *
+ * Revision 1.5 1999/10/22 22:47:50 mdw
+ * Grammar changes. Also, don't enable SIGINT if it's currently ignored.
+ *
* Revision 1.4 1999/10/10 16:46:12 mdw
* New resolver to initialize. Also, include options for grammar and
* options references.
#include "config.h"
+#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <signal.h>
#include <unistd.h>
#include <syslog.h>
+#include <grp.h>
+#include <pwd.h>
+
#include <mLib/bres.h>
#include <mLib/dstr.h>
#include <mLib/mdwopt.h>
#include "endpt.h"
#include "exec.h"
#include "fattr.h"
+#include "file.h"
#include "fw.h"
#include "scan.h"
+#include "socket.h"
#include "source.h"
/*----- Global variables --------------------------------------------------*/
/*----- Static variables --------------------------------------------------*/
+typedef struct conffile {
+ struct conffile *next;
+ char *name;
+} conffile;
+
static unsigned flags = 0; /* Global state flags */
static unsigned active = 0; /* Number of active things */
+static conffile *conffiles = 0; /* List of configuration files */
#define FW_SYSLOG 1u
#define FW_QUIET 2u
#define FW_SET 4u
-/*----- Main code ---------------------------------------------------------*/
+/*----- Configuration parsing ---------------------------------------------*/
+
+/* --- @parse@ --- *
+ *
+ * Arguments: @scanner *sc@ = pointer to scanner definition
+ *
+ * Returns: ---
+ *
+ * Use: Parses a configuration file from the scanner.
+ */
+
+static source_ops *sources[] =
+ { &xsource_ops, &fsource_ops, &ssource_ops, 0 };
+static target_ops *targets[] =
+ { &xtarget_ops, &ftarget_ops, &starget_ops, 0 };
+
+void parse(scanner *sc)
+{
+ token(sc);
+
+ for (;;) {
+ if (sc->t == CTOK_EOF)
+ break;
+ if (sc->t != CTOK_WORD)
+ error(sc, "parse error, keyword expected");
+
+ /* --- Handle a forwarding request --- */
+
+ if (strcmp(sc->d.buf, "forward") == 0 ||
+ strcmp(sc->d.buf, "fw") == 0 ||
+ strcmp(sc->d.buf, "from") == 0) {
+ source *s;
+ target *t;
+
+ token(sc);
+
+ /* --- Read a source description --- */
+
+ {
+ source_ops **sops;
+
+ /* --- Try to find a source type which understands --- */
+
+ s = 0;
+ for (sops = sources; *sops; sops++) {
+ if ((s = (*sops)->read(sc)) != 0)
+ goto found_source;
+ }
+ error(sc, "unknown source name `%s'", sc->d.buf);
+
+ /* --- Read any source-specific options --- */
+
+ found_source:
+ if (sc->t == '{') {
+ token(sc);
+ while (sc->t == CTOK_WORD) {
+ if (!s->ops->option || !s->ops->option(s, sc)) {
+ error(sc, "unknown %s source option `%s'",
+ s->ops->name, sc->d.buf);
+ }
+ if (sc->t == ';')
+ token(sc);
+ }
+ if (sc->t != '}')
+ error(sc, "parse error, missing `}'");
+ token(sc);
+ }
+ }
+
+ /* --- Read a destination description --- */
+
+ if (sc->t == CTOK_WORD && (strcmp(sc->d.buf, "to") == 0 ||
+ strcmp(sc->d.buf, "->") == 0))
+ token(sc);
+
+ {
+ target_ops **tops;
+
+ /* --- Try to find a target which understands --- */
+
+ t = 0;
+ for (tops = targets; *tops; tops++) {
+ if ((t = (*tops)->read(sc)) != 0)
+ goto found_target;
+ }
+ error(sc, "unknown target name `%s'", sc->d.buf);
+
+ /* --- Read any target-specific options --- */
+
+ found_target:
+ if (sc->t == '{') {
+ token(sc);
+ while (sc->t == CTOK_WORD) {
+ if (!t->ops->option || !t->ops->option(t, sc)) {
+ error(sc, "unknown %s target option `%s'",
+ t->ops->name, sc->d.buf);
+ }
+ if (sc->t == ';')
+ token(sc);
+ }
+ if (sc->t != '}')
+ error(sc, "parse error, `}' expected");
+ token(sc);
+ }
+ }
+
+ /* --- Combine the source and target --- */
+
+ s->ops->attach(s, sc, t);
+ }
+
+ /* --- Include configuration from a file --- *
+ *
+ * Slightly tricky. Scan the optional semicolon from the including
+ * stream, not the included one.
+ */
+
+ else if (strcmp(sc->d.buf, "include") == 0) {
+ FILE *fp;
+ dstr d = DSTR_INIT;
+
+ token(sc);
+ conf_name(sc, '/', &d);
+ if ((fp = fopen(d.buf, "r")) == 0)
+ error(sc, "can't include `%s': %s", d.buf, strerror(errno));
+ if (sc->t == ';')
+ token(sc);
+ pushback(sc);
+ scan_push(sc, scan_file(fp, d.buf, 0));
+ token(sc);
+ dstr_destroy(&d);
+ continue; /* Don't parse a trailing `;' */
+ }
+
+ /* --- Other configuration is handled elsewhere --- */
+
+ else {
+
+ /* --- First try among the sources --- */
+
+ {
+ source_ops **sops;
+
+ for (sops = sources; *sops; sops++) {
+ if ((*sops)->option && (*sops)->option(0, sc))
+ goto found_option;
+ }
+ }
+
+ /* --- Then try among the targets --- */
+
+ {
+ target_ops **tops;
+
+ for (tops = targets; *tops; tops++) {
+ if ((*tops)->option && (*tops)->option(0, sc))
+ goto found_option;
+ }
+ }
+
+ /* --- Nobody wants the option --- */
+
+ error(sc, "unknown global option or prefix `%s'", sc->d.buf);
+
+ found_option:;
+ }
+
+ if (sc->t == ';')
+ token(sc);
+ }
+}
+
+/*----- General utility functions -----------------------------------------*/
/* --- @fw_log@ --- *
*
t = time(0);
tm = localtime(&t);
DENSURE(&d, 64);
- d.len += strftime(d.buf, d.sz, "%Y-%m-%d %H:%M:%S", tm);
- DPUTC(&d, ' ');
+ d.len += strftime(d.buf, d.sz, "%Y-%m-%d %H:%M:%S ", tm);
va_start(ap, fmt);
- dstr_vputf(&d, fmt, ap);
+ dstr_vputf(&d, fmt, &ap);
va_end(ap);
if (flags & FW_SYSLOG)
syslog(LOG_NOTICE, "%s", d.buf);
static void fw_tidy(int n, void *p)
{
- const char *sn = "unexpected signal (bug!)";
- if (n == SIGTERM)
- sn = "SIGTERM";
- else if (n == SIGINT)
- sn = "SIGINT";
-
- fw_log(-1, "closing down on %s", sn);
- fw_exit();
+ const char *sn = 0;
+ switch (n) {
+ case SIGTERM: sn = "SIGTERM"; break;
+ case SIGINT: sn = "SIGINT"; break;
+ default: abort();
+ }
+
+ fw_log(-1, "closing down gracefully on %s", sn);
+ source_killall();
+}
+
+/* --- @fw_die@ --- *
+ *
+ * Arguments: @int n@ = signal number
+ * @void *p@ = an uninteresting argument
+ *
+ * Returns: ---
+ *
+ * Use: Handles various signals and causes an abrupt shutdown.
+ */
+
+static void fw_die(int n, void *p)
+{
+ const char *sn = 0;
+ switch (n) {
+ case SIGQUIT: sn = "SIGQUIT"; break;
+ default: abort();
+ }
+
+ fw_log(-1, "closing down abruptly on %s", sn);
+ source_killall();
+ endpt_killall();
+}
+
+/* --- @fw_reload@ --- *
+ *
+ * Arguments: @int n@ = a signal number
+ * @void *p@ = an uninteresting argument
+ *
+ * Returns: ---
+ *
+ * Use: Handles a hangup signal by re-reading configuration files.
+ */
+
+static void fw_reload(int n, void *p)
+{
+ FILE *fp;
+ scanner sc;
+ conffile *cf;
+
+ assert(n == SIGHUP);
+ if (!conffiles) {
+ fw_log(-1, "no configuration files to reload: ignoring SIGHUP");
+ return;
+ }
+ fw_log(-1, "reloading configuration files...");
+ source_killall();
+ scan_create(&sc);
+ for (cf = conffiles; cf; cf = cf->next) {
+ if ((fp = fopen(cf->name, "r")) == 0)
+ fw_log(-1, "error loading `%s': %s", cf->name, strerror(errno));
+ else
+ scan_add(&sc, scan_file(fp, cf->name, 0));
+ }
+ parse(&sc);
+ fw_log(-1, "... reload completed OK");
}
+/*----- Startup and options parsing ---------------------------------------*/
+
/* --- Standard GNU help options --- */
static void version(FILE *fp)
static void usage(FILE *fp)
{
- pquis(fp, "Usage: $ [-db] [-f file] [config statements...]\n");
+ pquis(fp, "Usage: $ [-dql] [-f file] [config statements...]\n");
}
static void help(FILE *fp)
of the functionality of inetd, netcat, and normal cat. Options available\n\
are:\n\
\n\
--h, --help Display this help message.\n\
--v, --version Display the program's version number.\n\
--u, --usage Display a terse usage summary.\n\
+-h, --help Display this help message.\n\
+-v, --version Display the program's version number.\n\
+-u, --usage Display a terse usage summary.\n\
\n\
--g, --grammar Show a summary of the configuration language.\n\
--o, --options Show a summary of the source and target options.\n\
+-G, --grammar Show a summary of the configuration language.\n\
+-O, --options Show a summary of the source and target options.\n\
\n\
--f, --file=FILE Read configuration from a file.\n\
--d, --daemon Fork into background after initializing.\n\
+-f, --file=FILE Read configuration from a file.\n\
+-q, --quiet Don't emit any logging information.\n\
+-d, --daemon Fork into background after initializing.\n\
+-l, --syslog Send log output to the system logger.\n\
+-s, --setuid=USER Change uid to USER after initializing sources.\n\
+-g, --setgid=GRP Change gid to GRP after initializing sources.\n\
\n\
Configuration may be supplied in one or more configuration files, or on\n\
the command line (or both). If no `-f' option is present, and no\n\
Grammar summary\n\
\n\
Basic syntax\n\
- file ::= empty | file stmt [`;']\n\
- stmt ::= option-stmt | fw-stmt\n\
- fw-stmt ::= `fw' source options [`to'|`->'] target options\n\
- options ::= `{' option-seq `}'\n\
- option-seq ::= empty | option-stmt [`;'] option-seq\n\
+ FILE ::= EMPTY | FILE STMT [`;']\n\
+ STMT ::= OPTION-STMT | FW-STMT\n\
+ FW-STMT ::= `fw' SOURCE OPTIONS [`to'|`->'] TARGET OPTIONS\n\
+ OPTIONS ::= `{' OPTION-SEQ `}'\n\
+ OPTION-SEQ ::= EMPTY | OPTION-STMT [`;'] OPTION-SEQ\n\
\n\
Option syntax\n\
- option-stmt ::= q-option\n\
- q-option ::= option\n\
- | prefix `.' q-option\n\
- | prefix `{' option-seq `}'\n\
- prefix ::= word\n\
+ OPTION-STMT ::= Q-OPTION\n\
+ Q-OPTION ::= OPTION\n\
+ | PREFIX `.' Q-OPTION\n\
+ | PREFIX `{' OPTION-SEQ `}'\n\
+ PREFIX ::= WORD\n\
\n\
File source and target\n\
- source ::= file\n\
- target ::= file\n\
- file ::= `file' [`.'] fspec [`,' fspec]\n\
- fspec ::= fd-spec | name-spec | null-spec\n\
- fd-spec ::= [[`:']`fd'[`:']] number|`stdin'|`stdout'\n\
- name-spec ::= [[`:']`file'[`:']] file-name\n\
- file-name ::= path-seq | [ path-seq ]\n\
- path-seq ::= path-elt | path-seq path-elt\n\
- path-elt ::= `/' | word\n\
- null-spec ::= [`:']`null'[`:']\n\
+ SOURCE ::= FILE\n\
+ TARGET ::= FILE\n\
+ FILE ::= `file' [`.'] FSPEC [`,' FSPEC]\n\
+ FSPEC ::= FD-SPEC | NAME-SPEC | NULL-SPEC\n\
+ FD-SPEC ::= [[`:']`fd'[`:']] NUMBER|`stdin'|`stdout'\n\
+ NAME-SPEC ::= [[`:']`file'[`:']] FILE-NAME\n\
+ FILE-NAME ::= PATH-SEQ | [ PATH-SEQ ]\n\
+ PATH-SEQ ::= PATH-ELT | PATH-SEQ PATH-ELT\n\
+ PATH-ELT ::= `/' | WORD\n\
+ NULL-SPEC ::= [`:']`null'[`:']\n\
\n\
Exec source and target\n\
- source ::= exec\n\
- target ::= exec\n\
- exec ::= `exec' [`.'] cmd-spec\n\
- cmd-spec ::= shell-cmd | [prog-name] `[' argv0 arg-seq `]'\n\
- arg-seq ::= word | arg-seq word\n\
- shell-cmd ::= word\n\
- argv0 ::= word\n\
+ SOURCE ::= EXEC\n\
+ TARGET ::= EXEC\n\
+ EXEC ::= `exec' [`.'] CMD-SPEC\n\
+ CMD-SPEC ::= SHELL-CMD | [PROG-NAME] `[' ARGV0 ARG-SEQ `]'\n\
+ ARG-SEQ ::= WORD | ARG-SEQ WORD\n\
+ SHELL-CMD ::= WORD\n\
+ ARGV0 ::= WORD\n\
\n\
Socket source and target\n\
- source ::= socket-source\n\
- target ::= socket-target\n\
- socket-source ::= [`socket'[`.']] [[`:']addr-type[`:']] source-addr\n\
- socket-target ::= [`socket'[`.']] [[`:']addr-type[`:']] target-addr\n\
+ SOURCE ::= SOCKET-SOURCE\n\
+ TARGET ::= SOCKET-TARGET\n\
+ SOCKET-SOURCE ::= [`socket'[`.']] [[`:']ADDR-TYPE[`:']] SOURCE-ADDR\n\
+ SOCKET-TARGET ::= [`socket'[`.']] [[`:']ADDR-TYPE[`:']] TARGET-ADDR\n\
\n\
- inet-source-addr ::= [port] port\n\
- inet-target-addr ::= address [`:'] port\n\
- address ::= addr-elt | address addr-elt\n\
- addr-elt ::= `.' | word\n\
+ INET-SOURCE-ADDR ::= [`port'] PORT\n\
+ INET-TARGET-ADDR ::= ADDRESS [`:'] PORT\n\
+ ADDRESS ::= ADDR-ELT | ADDRESS ADDR-ELT\n\
+ ADDR-ELT ::= `.' | WORD\n\
\n\
- unix-source-addr ::= file-name\n\
- unix-target-addr ::= file-name\n\
+ UNIX-SOURCE-ADDR ::= FILE-NAME\n\
+ UNIX-TARGET-ADDR ::= FILE-NAME\n\
");
}
Options summary\n\
\n\
File attributes (`fattr')\n\
- prefix.fattr.mode [=] mode\n\
- prefix.fattr.owner [=] user\n\
- prefix.fattr.group [=] group\n\
+ prefix.FATTR.MODE [=] MODE\n\
+ prefix.FATTR.OWNER [=] USER\n\
+ prefix.FATTR.GROUP [=] GROUP\n\
\n\
File options\n\
file.create [=] yes|no\n\
\n\
Exec options\n\
exec.logging [=] yes|no\n\
- exec.dir [=] file-name\n\
- exec.root [=] file-name\n\
- exec.user [=] user\n\
- exec.group [=] group\n\
- exec.rlimit.limit[.hard|.soft] [=] value\n\
+ exec.dir [=] FILE-NAME\n\
+ exec.root [=] FILE-NAME\n\
+ exec.user [=] USER\n\
+ exec.group [=] GROUP\n\
+ exec.rlimit.LIMIT[.hard|.soft] [=] VALUE\n\
exec.env.clear\n\
- exec.env.unset var\n\
- exec.env.[set] var [=] value\n\
+ exec.env.unset VAR\n\
+ exec.env.[set] VAR [=] VALUE\n\
\n\
Socket options\n\
- socket.conn [=] number\n\
+ socket.conn [=] NUMBER|unlimited|one-shot\n\
+ socket.listen [=] NUMBER\n\
socket.logging [=] yes|no\n\
- socket.inet.[allow|deny] [from] address [/ address]\n\
+\n\
+ socket.inet.source.[allow|deny] [host] ADDR [/ ADDR]\n\
+ socket.inet.source.[allow|deny] priv-port\n\
+ socket.inet.source.addr [=] any|ADDR\n\
+ socket.inet.dest.addr [=] any|ADDR\n\
+\n\
socket.unix.fattr.*\n\
");
}
{
unsigned f = 0;
sel_state sst;
- sig s_term, s_int;
+ sig s_term, s_quit, s_int, s_hup;
scanner sc;
+ uid_t drop = -1;
+ gid_t dropg = -1;
+ conffile *cf, **cff = &conffiles;
- enum {
- f_bogus = 1,
- f_file = 2,
- f_fork = 8
- };
+#define f_bogus 1u
+#define f_file 2u
+#define f_syslog 4u
+#define f_fork 8u
/* --- Initialize things --- */
fattr_init(&fattr_global);
scan_create(&sc);
- /* --- Set up some signal handlers --- */
-
- sig_add(&s_term, SIGTERM, fw_tidy, 0);
- sig_add(&s_int, SIGINT, fw_tidy, 0);
atexit(fw_exit);
/* --- Parse command line options --- */
/* --- Other help options --- */
- { "grammar", 0, 0, 'g' },
- { "options", 0, 0, 'o' },
+ { "grammar", 0, 0, 'G' },
+ { "options", 0, 0, 'O' },
/* --- Other useful arguments --- */
{ "file", OPTF_ARGREQ, 0, 'f' },
{ "fork", 0, 0, 'd' },
{ "daemon", 0, 0, 'd' },
+ { "syslog", 0, 0, 'l' },
+ { "log", 0, 0, 'l' },
{ "quiet", 0, 0, 'q' },
+ { "setuid", OPTF_ARGREQ, 0, 's' },
+ { "uid", OPTF_ARGREQ, 0, 's' },
+ { "setgid", OPTF_ARGREQ, 0, 'g' },
+ { "gid", OPTF_ARGREQ, 0, 'g' },
/* --- Magic terminator --- */
{ 0, 0, 0, 0 }
};
- int i = mdwopt(argc, argv, "+hvu go f:d", opts, 0, 0, 0);
+ int i = mdwopt(argc, argv, "+hvu GO f:dls:g:", opts, 0, 0, 0);
if (i < 0)
break;
usage(stdout);
exit(0);
break;
- case 'g':
+ case 'G':
grammar(stdout);
exit(0);
break;
- case 'o':
+ case 'O':
options(stdout);
exit(0);
break;
FILE *fp;
if ((fp = fopen(optarg, "r")) == 0)
die(1, "couldn't open file `%s': %s", optarg, strerror(errno));
+ cf = CREATE(conffile);
+ cf->name = optarg;
+ *cff = cf;
+ cff = &cf->next;
scan_add(&sc, scan_file(fp, optarg, 0));
}
f |= f_file;
case 'd':
f |= f_fork;
break;
+ case 'l':
+ f |= f_syslog;
+ break;
case 'q':
flags |= FW_QUIET;
break;
+ case 's':
+ if (isdigit((unsigned char )optarg[0])) {
+ char *q;
+ drop = strtol(optarg, &q, 0);
+ if (*q)
+ die(1, "bad uid `%s'", optarg);
+ } else {
+ struct passwd *pw = getpwnam(optarg);
+ if (!pw)
+ die(1, "unknown user `%s'", optarg);
+ drop = pw->pw_uid;
+ }
+ break;
+ case 'g':
+ if (isdigit((unsigned char )optarg[0])) {
+ char *q;
+ dropg = strtol(optarg, &q, 0);
+ if (*q)
+ die(1, "bad gid `%s'", optarg);
+ } else {
+ struct group *gr = getgrnam(optarg);
+ if (!gr)
+ die(1, "unknown group `%s'", optarg);
+ dropg = gr->gr_gid;
+ }
+ break;
default:
f |= f_bogus;
break;
usage(stderr);
exit(1);
}
+ *cff = 0;
/* --- Deal with the remaining arguments --- */
/* --- Parse the configuration now gathered --- */
- conf_parse(&sc);
+ parse(&sc);
+
+ /* --- Set up some signal handlers --- *
+ *
+ * Don't enable @SIGINT@ if the caller already disabled it.
+ */
+
+ {
+ struct sigaction sa;
+
+ sig_add(&s_term, SIGTERM, fw_tidy, 0);
+ sig_add(&s_quit, SIGQUIT, fw_die, 0);
+ sigaction(SIGINT, 0, &sa);
+ if (sa.sa_handler != SIG_IGN)
+ sig_add(&s_int, SIGINT, fw_tidy, 0);
+ sig_add(&s_hup, SIGHUP, fw_reload, 0);
+ }
+
+ /* --- Drop privileges --- */
+
+#ifdef HAVE_SETGROUPS
+ if ((dropg != (gid_t)-1 && (setgid(dropg) || setgroups(1, &dropg))) ||
+ (drop != (uid_t)-1 && setuid(drop)))
+ die(1, "couldn't drop privileges: %s", strerror(errno));
+#else
+ if ((dropg != (gid_t)-1 && setgid(dropg)) ||
+ (drop != (uid_t)-1 && setuid(drop)))
+ die(1, "couldn't drop privileges: %s", strerror(errno));
+#endif
/* --- Fork into the background --- */
kid = fork();
if (kid != 0)
_exit(0);
+ }
+ if (f & f_syslog) {
flags |= FW_SYSLOG;
openlog(QUIS, 0, LOG_DAEMON);
}
if (!(flags & FW_SET))
moan("nothing to do!");
signal(SIGPIPE, SIG_IGN);
- while (active)
- sel_select(sel);
+
+ {
+ int selerr = 0;
+ while (active) {
+ if (!sel_select(sel))
+ selerr = 0;
+ else if (errno != EINTR && errno != EAGAIN) {
+ fw_log(-1, "error from select: %s", strerror(errno));
+ selerr++;
+ if (selerr > 8) {
+ fw_log(-1, "too many consecutive select errors: bailing out");
+ exit(EXIT_FAILURE);
+ }
+ }
+ }
+ }
+
return (0);
}
~mdw / fwd / blobdiff