X-Git-Url: https://git.distorted.org.uk/~mdw/fwd/blobdiff_plain/06d823120f122fb9a9f0c291ad5b882efb17d199..f9d40245f5a776b34e0f0dcc2aad164e3b3d02af:/fw.c diff --git a/fw.c b/fw.c index e5537fc..6b8f16d 100644 --- a/fw.c +++ b/fw.c @@ -1,6 +1,6 @@ /* -*-c-*- * - * $Id: fw.c,v 1.5 1999/10/22 22:47:50 mdw Exp $ + * $Id: fw.c,v 1.9 2001/01/20 11:55:17 mdw Exp $ * * Port forwarding thingy * @@ -29,6 +29,19 @@ /*----- 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. * @@ -64,6 +77,9 @@ #include #include +#include +#include + #include #include #include @@ -120,8 +136,7 @@ void fw_log(time_t t, const char *fmt, ...) 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); va_end(ap); @@ -193,7 +208,7 @@ 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) @@ -206,15 +221,19 @@ 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\ +-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\ @@ -340,10 +359,13 @@ int main(int argc, char *argv[]) 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_syslog = 4, f_fork = 8 }; @@ -389,21 +411,27 @@ int main(int argc, char *argv[]) /* --- 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; @@ -420,11 +448,11 @@ int main(int argc, char *argv[]) usage(stdout); exit(0); break; - case 'g': + case 'G': grammar(stdout); exit(0); break; - case 'o': + case 'O': options(stdout); exit(0); break; @@ -442,9 +470,38 @@ int main(int argc, char *argv[]) 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; @@ -474,6 +531,18 @@ int main(int argc, char *argv[]) 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 --- */ if (f & f_fork) { @@ -492,7 +561,9 @@ 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); } @@ -502,8 +573,23 @@ int main(int argc, char *argv[]) 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 { + 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); }