X-Git-Url: https://git.distorted.org.uk/~mdw/fwd/blobdiff_plain/a8b9c5eb837178fbf0ce7b4db2d3e067c1151b65..a9bd543ab4ebe415bca9d6f27b90f16ddac79bc0:/fw.c diff --git a/fw.c b/fw.c index 3d3f336..4b0a861 100644 --- a/fw.c +++ b/fw.c @@ -1,13 +1,11 @@ /* -*-c-*- * - * $Id: fw.c,v 1.11 2001/02/03 20:33:26 mdw Exp $ - * * Port forwarding thingy * * (c) 1999 Straylight/Edgeware */ -/*----- Licensing notice --------------------------------------------------* +/*----- Licensing notice --------------------------------------------------* * * This file is part of the `fw' port forwarder. * @@ -15,94 +13,18 @@ * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. - * + * * `fw' is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. - * + * * You should have received a copy of the GNU General Public License * along with `fw'; if not, write to the Free Software Foundation, * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ -/*----- Revision history --------------------------------------------------* - * - * $Log: fw.c,v $ - * 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. - * - * Revision 1.3 1999/07/26 23:30:42 mdw - * Major reconstruction work for new design. - * - * Revision 1.2 1999/07/03 13:55:17 mdw - * Various changes. Add configuration grammar to help text. Change to - * root directory and open syslog when forking into background. - * - * Revision 1.1.1.1 1999/07/01 08:56:23 mdw - * Initial revision. - * - */ - -/*----- Header files ------------------------------------------------------*/ - -#include "config.h" - -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#include -#include - -#include -#include - -#include -#include -#include -#include -#include -#include -#include -#include - -#include "conf.h" -#include "endpt.h" -#include "exec.h" -#include "fattr.h" #include "fw.h" -#include "scan.h" -#include "source.h" /*----- Global variables --------------------------------------------------*/ @@ -123,7 +45,181 @@ static conffile *conffiles = 0; /* List of configuration files */ #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); + if (t->ops->confirm) + t->ops->confirm(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@ --- * * @@ -151,7 +247,7 @@ void fw_log(time_t t, const char *fmt, ...) DENSURE(&d, 64); 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); @@ -266,10 +362,12 @@ static void fw_reload(int n, void *p) else scan_add(&sc, scan_file(fp, cf->name, 0)); } - conf_parse(&sc); + parse(&sc); fw_log(-1, "... reload completed OK"); } +/*----- Startup and options parsing ---------------------------------------*/ + /* --- Standard GNU help options --- */ static void version(FILE *fp) @@ -279,7 +377,7 @@ static void version(FILE *fp) static void usage(FILE *fp) { - pquis(fp, "Usage: $ [-dql] [-f file] [config statements...]\n"); + pquis(fp, "Usage: $ [-dql] [-p PIDFILE] [-f FILE] [CONFIG-STMTS...]\n"); } static void help(FILE *fp) @@ -289,22 +387,7 @@ static void help(FILE *fp) usage(fp); pquis(fp, "\n\ An excessively full-featured port-forwarder, which subsumes large chunks\n\ -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\ -\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\ --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\ +of the functionality of inetd, netcat, and normal cat.\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\ @@ -317,6 +400,26 @@ to be a separate line.\n\ \n\ The grammar is fairly complicated. For a summary, run `$ --grammar'.\n\ For a summary of the various options, run `$ --options'.\n\ +\n\ +Options available are:\n\ +\n\ +Help options:\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\ +Configuration summary:\n\ + -G, --grammar Show a summary of the configuration language.\n\ + -O, --options Show a summary of the source and target options.\n\ +\n\ +Other options:\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\ + -p, --pidfile=FILE Write process-id to the named FILE.\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\ "); } @@ -325,93 +428,15 @@ For a summary of the various options, run `$ --options'.\n\ static void grammar(FILE *fp) { version(fp); - pquis(fp, "\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\ -\n\ -Option syntax\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\ -\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\ -\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\ -\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\ -"); + fputs("\nGrammar summary\n\n", fp); + fputs(grammar_text, fp); } static void options(FILE *fp) { version(fp); - pquis(fp, "\n\ -Options summary\n\ -\n\ -File attributes (`fattr')\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\ - file.open [=] no|truncate|append\n\ - file.fattr.*\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.env.clear\n\ - exec.env.unset var\n\ - exec.env.[set] var [=] value\n\ -\n\ -Socket options\n\ - socket.conn [=] number|unlimited|one-shot\n\ - socket.logging [=] yes|no\n\ - socket.inet.[allow|deny] [from] address [/ address]\n\ - socket.unix.fattr.*\n\ -"); + fputs("\nOption summary\n\n", fp); + fputs(option_text, fp); } /* --- @main@ --- * @@ -432,6 +457,7 @@ int main(int argc, char *argv[]) scanner sc; uid_t drop = -1; gid_t dropg = -1; + const char *pidfile = 0; conffile *cf, **cff = &conffiles; #define f_bogus 1u @@ -475,6 +501,7 @@ int main(int argc, char *argv[]) { "file", OPTF_ARGREQ, 0, 'f' }, { "fork", 0, 0, 'd' }, { "daemon", 0, 0, 'd' }, + { "pidfile", OPTF_ARGREQ, 0, 'p' }, { "syslog", 0, 0, 'l' }, { "log", 0, 0, 'l' }, { "quiet", 0, 0, 'q' }, @@ -487,7 +514,7 @@ int main(int argc, char *argv[]) { 0, 0, 0, 0 } }; - int i = mdwopt(argc, argv, "+hvu GO f:dls:g:", opts, 0, 0, 0); + int i = mdwopt(argc, argv, "+hvu" "GO" "f:dp:ls:g:", opts, 0, 0, 0); if (i < 0) break; @@ -530,6 +557,9 @@ int main(int argc, char *argv[]) case 'd': f |= f_fork; break; + case 'p': + pidfile = optarg; + break; case 'l': f |= f_syslog; break; @@ -537,7 +567,7 @@ int main(int argc, char *argv[]) flags |= FW_QUIET; break; case 's': - if (isdigit((unsigned char )optarg[0])) { + if (isdigit((unsigned char )optarg[0])) { char *q; drop = strtol(optarg, &q, 0); if (*q) @@ -550,7 +580,7 @@ int main(int argc, char *argv[]) } break; case 'g': - if (isdigit((unsigned char )optarg[0])) { + if (isdigit((unsigned char )optarg[0])) { char *q; dropg = strtol(optarg, &q, 0); if (*q) @@ -590,7 +620,7 @@ int main(int argc, char *argv[]) /* --- Parse the configuration now gathered --- */ - conf_parse(&sc); + parse(&sc); /* --- Set up some signal handlers --- * * @@ -608,18 +638,6 @@ int main(int argc, char *argv[]) sig_add(&s_hup, SIGHUP, fw_reload, 0); } - /* --- Drop privileges --- */ - -#ifdef HAVE_SETGROUPS - if ((dropg != -1 && (setgid(dropg) || setgroups(1, &dropg))) || - (drop != -1 && setuid(drop))) - die(1, "couldn't drop privileges: %s", strerror(errno)); -#else - if ((dropg != -1 && setgid(dropg)) || - (drop != -1 && setuid(drop))) - die(1, "couldn't drop privileges: %s", strerror(errno)); -#endif - /* --- Fork into the background --- */ if (f & f_fork) { @@ -639,12 +657,38 @@ int main(int argc, char *argv[]) if (kid != 0) _exit(0); } + if (pidfile) { + FILE *fp = fopen(pidfile, "w"); + if (!fp) { + die(EXIT_FAILURE, "couldn't create pidfile `%s': %s", + pidfile, strerror(errno)); + } + fprintf(fp, "%lu\n", (unsigned long)getpid()); + if (fflush(fp) || ferror(fp) || fclose(fp)) { + die(EXIT_FAILURE, "couldn't write pidfile `%s': %s", + pidfile, strerror(errno)); + } + } if (f & f_syslog) { flags |= FW_SYSLOG; openlog(QUIS, 0, LOG_DAEMON); } + /* --- Drop privileges --- */ + + if (drop != (uid_t)-1) + privconn_split(sel); +#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 + /* --- Let rip --- */ if (!(flags & FW_SET)) @@ -655,7 +699,7 @@ int main(int argc, char *argv[]) int selerr = 0; while (active) { if (!sel_select(sel)) - selerr = 0; + selerr = 0; else if (errno != EINTR && errno != EAGAIN) { fw_log(-1, "error from select: %s", strerror(errno)); selerr++; @@ -666,7 +710,7 @@ int main(int argc, char *argv[]) } } } - + return (0); }