X-Git-Url: https://git.distorted.org.uk/~mdw/fwd/blobdiff_plain/afd7451e40e07118103fcc81e3b635a164c545c4..f9d40245f5a776b34e0f0dcc2aad164e3b3d02af:/fw.c diff --git a/fw.c b/fw.c index 04235d4..6b8f16d 100644 --- a/fw.c +++ b/fw.c @@ -1,10 +1,10 @@ /* -*-c-*- * - * $Id: fw.c,v 1.2 1999/07/03 13:55:17 mdw Exp $ + * $Id: fw.c,v 1.9 2001/01/20 11:55:17 mdw Exp $ * * Port forwarding thingy * - * (c) 1999 Mark Wooding + * (c) 1999 Straylight/Edgeware */ /*----- Licensing notice --------------------------------------------------* @@ -29,6 +29,29 @@ /*----- Revision history --------------------------------------------------* * * $Log: fw.c,v $ + * 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. @@ -44,44 +67,148 @@ #include #include +#include +#include #include #include #include +#include #include #include +#include +#include + +#include +#include #include #include #include #include +#include #include -#include "acl.h" -#include "bres.h" #include "conf.h" +#include "endpt.h" +#include "exec.h" +#include "fattr.h" #include "fw.h" -#include "listener.h" #include "scan.h" +#include "source.h" /*----- Global variables --------------------------------------------------*/ sel_state *sel; /* Multiplexor for nonblocking I/O */ -unsigned flags = 0; /* Global state flags */ + +/*----- Static variables --------------------------------------------------*/ + +static unsigned flags = 0; /* Global state flags */ +static unsigned active = 0; /* Number of active things */ + +#define FW_SYSLOG 1u +#define FW_QUIET 2u +#define FW_SET 4u /*----- Main code ---------------------------------------------------------*/ +/* --- @fw_log@ --- * + * + * Arguments: @time_t t@ = when the connection occurred or (@-1@) + * @const char *fmt@ = format string to fill in + * @...@ = other arguments + * + * Returns: --- + * + * Use: Logs a connection. + */ + +void fw_log(time_t t, const char *fmt, ...) +{ + struct tm *tm; + dstr d = DSTR_INIT; + va_list ap; + + if (flags & FW_QUIET) + return; + + if (t == -1) + t = time(0); + tm = localtime(&t); + 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); + va_end(ap); + if (flags & FW_SYSLOG) + syslog(LOG_NOTICE, "%s", d.buf); + else { + DPUTC(&d, '\n'); + dstr_write(&d, stderr); + } + DDESTROY(&d); +} + +/* --- @fw_inc@, @fw_dec@ --- * + * + * Arguments: --- + * + * Returns: --- + * + * Use: Increments or decrements the active thing count. `fw' won't + * quit while there are active things. + */ + +void fw_inc(void) { flags |= FW_SET; active++; } +void fw_dec(void) { if (active) active--; } + +/* --- @fw_exit@ --- * + * + * Arguments: --- + * + * Returns: --- + * + * Use: Exits when appropriate. + */ + +static void fw_exit(void) +{ + endpt_killall(); + source_killall(); +} + +/* --- @fw_tidy@ --- * + * + * Arguments: @int n@ = signal number + * @void *p@ = an uninteresting argument + * + * Returns: --- + * + * Use: Handles various signals and causes a clean tidy-up. + */ + +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(); +} + /* --- Standard GNU help options --- */ static void version(FILE *fp) { - fprintf(fp, "%s version " VERSION "\n", QUIS); + pquis(fp, "$ version " VERSION "\n"); } static void usage(FILE *fp) { - fprintf(stderr, "Usage: %s [-db] [-f file] [config statements...]\n", - QUIS); + pquis(fp, "Usage: $ [-dql] [-f file] [config statements...]\n"); } static void help(FILE *fp) @@ -89,16 +216,24 @@ static void help(FILE *fp) version(fp); fputc('\n', fp); usage(fp); - fputs("\n\ -A fairly full-featured port-forwarder. Options available are:\n\ + 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\ --h, --help Display this help message.\n\ --v, --version Display the program's version number.\n\ --u, --usage Display a terse usage 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\ --f, --file=FILE Read configuration from a file.\n\ --d, --dump Dump the configuration to standard output.\n\ --b, --background 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\ @@ -107,14 +242,105 @@ read.\n\ \n\ Configuration is free-form. Comments begin with a `#' character and\n\ continue to the end of the line. Each command line argument is considered\n\ -to be a separate line. The syntax is as follows:\n\ +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\ +"); +} + +/* --- Other helpful options --- */ + +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\ +"); +} + +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\ -config : stmt...\n\ -stmt : fwd-stmt | acl-stmt\n\ -fwd-stmt : `forward' [`port'] port [`to'] addr [`:'] port [fwd-attr] [`;']\n\ -fwd-attr : `{' acl-stmt... `}'\n\ -acl-stmt : (`allow' | `deny') [`from'] addr [`/' mask] [`;']\n\ -", fp); +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\ +"); } /* --- @main@ --- * @@ -131,11 +357,15 @@ int main(int argc, char *argv[]) { unsigned f = 0; sel_state sst; + sig s_term, s_int; + scanner sc; + uid_t drop = -1; + gid_t dropg = -1; enum { f_bogus = 1, f_file = 2, - f_dump = 4, + f_syslog = 4, f_fork = 8 }; @@ -145,7 +375,28 @@ int main(int argc, char *argv[]) sel = &sst; sel_init(sel); sub_init(); + sig_init(sel); bres_init(sel); + bres_exec(0); + exec_init(); + fattr_init(&fattr_global); + scan_create(&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); + sigaction(SIGINT, 0, &sa); + if (sa.sa_handler != SIG_IGN) + sig_add(&s_int, SIGINT, fw_tidy, 0); + } + + atexit(fw_exit); /* --- Parse command line options --- */ @@ -158,18 +409,29 @@ int main(int argc, char *argv[]) { "version", 0, 0, 'v' }, { "usage", 0, 0, 'u' }, + /* --- Other help options --- */ + + { "grammar", 0, 0, 'G' }, + { "options", 0, 0, 'O' }, + /* --- Other useful arguments --- */ { "file", OPTF_ARGREQ, 0, 'f' }, - { "dump", 0, 0, 'd' }, - { "fork", 0, 0, 'b' }, - { "background", 0, 0, 'b' }, + { "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 f:db", opts, 0, 0, 0); + int i = mdwopt(argc, argv, "+hvu GO f:dls:g:", opts, 0, 0, 0); if (i < 0) break; @@ -186,22 +448,60 @@ int main(int argc, char *argv[]) usage(stdout); exit(0); break; - case 'f': { - scan_filectx ctx; - FILE *fp; - if ((fp = fopen(optarg, "r")) == 0) - die(1, "couldn't open file `%s': %s", optarg, strerror(errno)); - scan_fileinit(&ctx, fp, optarg); - conf_parse(&ctx); - fclose(fp); + case 'G': + grammar(stdout); + exit(0); + break; + case 'O': + options(stdout); + exit(0); + break; + case 'f': + if (strcmp(optarg, "-") == 0) + scan_add(&sc, scan_file(stdin, "", SCF_NOCLOSE)); + else { + FILE *fp; + if ((fp = fopen(optarg, "r")) == 0) + die(1, "couldn't open file `%s': %s", optarg, strerror(errno)); + scan_add(&sc, scan_file(fp, optarg, 0)); + } f |= f_file; - } break; - case 'd': - f |= f_dump; break; - case 'b': + 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; @@ -215,34 +515,33 @@ int main(int argc, char *argv[]) /* --- Deal with the remaining arguments --- */ - if (optind == argc) { - if (f & f_file) - /* Cool */; - else if (isatty(STDIN_FILENO)) { - moan("no configuration given and stdin is a terminal."); - moan("type `%s --help' for usage information.", QUIS); - exit(1); - } else { - scan_filectx ctx; - scan_fileinit(&ctx, stdin, ""); - conf_parse(&ctx); - } - } else { - scan_argvctx ctx; - scan_argvinit(&ctx, argv + optind); - conf_parse(&ctx); + if (optind < argc) + scan_add(&sc, scan_argv(argv + optind)); + else if (f & f_file) + /* Cool */; + else if (!isatty(STDIN_FILENO)) + scan_add(&sc, scan_file(stdin, "", SCF_NOCLOSE)); + else { + moan("no configuration given and stdin is a terminal."); + moan("type `%s --help' for usage information.", QUIS); + exit(1); } - /* --- Dump out the state --- */ + /* --- Parse the configuration now gathered --- */ - if (f & f_dump) { - sel_file *s; - fputs("global acl:\n", stdout); - acl_dump(0, stdout); - for (s = sel->files; s; s = s->next) - listener_dump((listener *)s, stdout); - exit(0); - } + conf_parse(&sc); + + /* --- 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 --- */ @@ -262,15 +561,35 @@ int main(int argc, char *argv[]) kid = fork(); if (kid != 0) _exit(0); + } + if (f & f_syslog) { flags |= FW_SYSLOG; openlog(QUIS, 0, LOG_DAEMON); } /* --- Let rip --- */ - for (;;) - sel_select(sel); + if (!(flags & FW_SET)) + moan("nothing to do!"); + signal(SIGPIPE, SIG_IGN); + + { + int selerr = 0; + while (active) { + if (!sel_select(sel)) + selerr = 0; + else { + 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); }