From fc170a33ade808c25d6a7dee7dd00aba290477c3 Mon Sep 17 00:00:00 2001 From: mdw Date: Thu, 23 Mar 2000 00:37:33 +0000 Subject: [PATCH] Add option to change user and group after initialization. Naughtily reassign short equivalents of --grammar and --options. --- fw.1 | 34 ++++++++++++++++++++++++++++++++-- fw.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++------ 2 files changed, 89 insertions(+), 8 deletions(-) diff --git a/fw.1 b/fw.1 index 2d23b0d..df52079 100644 --- a/fw.1 +++ b/fw.1 @@ -1,6 +1,6 @@ .\" -*-nroff-*- .\" -.\" $Id: fw.1,v 1.8 1999/12/22 15:44:43 mdw Exp $ +.\" $Id: fw.1,v 1.9 2000/03/23 00:37:33 mdw Exp $ .\" .\" Manual page for fw .\" @@ -28,6 +28,10 @@ .\" ---- Revision history --------------------------------------------------- .\" .\" $Log: fw.1,v $ +.\" Revision 1.9 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 1.8 1999/12/22 15:44:43 mdw .\" Fix some errors, and document new option. .\" @@ -129,6 +133,10 @@ fw \- port forwarder .RB [ \-dlq ] .RB [ \-f .IR file ] +.RB [ \-s +.IR user ] +.RB [ \-g +.IR group ] .IR config-stmt ... . .\"-------------------------------------------------------------------------- @@ -175,6 +183,14 @@ Writes the version number to standard output and exits successfully. .B "\-u, \-\-usage" Writes a terse usage summary to standard output and exits successfully. .TP +.B "\-G, \-\-grammar" +Writes a summary of the configuration file grammar to standard output +and exits successfully. +.TP +.B "\-O, \-\-options" +Writes a summary of the source and target options to standard output and +exits successfully. +.TP .BI "\-f, \-\-file=" file Read configuration information from .IR file . @@ -190,10 +206,24 @@ initializing properly. .B "\-l, \-\-syslog, \-\-log" Emit logging information to the system log, rather than standard error. .TP -.B "-q, \-\-quiet" +.B "\-q, \-\-quiet" Don't output any logging information. This option is not recommended for normal use, although it can make system call traces clearer so I use it when debugging. +.TP +.BI "\-s, \-\-setuid=" user +Change uid to that of +.IR user , +which may be either a user name or uid number, after initializing all +the sources. This will usually require elevated privileges. +.TP +.BI "\-g, \-\-setgid=" group +Change gid to that of +.IR group , +which may be either a group name or gid number, after initializing all +the sources. If the operating system understands supplementary groups +then the supplementary groups list is altered to include only +.IR group . .PP Any further command line arguments are interpreted as configuration lines to be read. Configuration supplied in command line arguments has diff --git a/fw.c b/fw.c index 4db1fdb..68871a6 100644 --- a/fw.c +++ b/fw.c @@ -1,6 +1,6 @@ /* -*-c-*- * - * $Id: fw.c,v 1.6 1999/12/22 15:44:10 mdw Exp $ + * $Id: fw.c,v 1.7 2000/03/23 00:37:33 mdw Exp $ * * Port forwarding thingy * @@ -29,6 +29,10 @@ /*----- Revision history --------------------------------------------------* * * $Log: fw.c,v $ + * 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. * @@ -67,6 +71,9 @@ #include #include +#include +#include + #include #include #include @@ -212,13 +219,15 @@ are:\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\ -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\ @@ -344,6 +353,8 @@ 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, @@ -405,12 +416,16 @@ int main(int argc, char *argv[]) { "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:dl", opts, 0, 0, 0); + int i = mdwopt(argc, argv, "+hvu GO f:dls:g:", opts, 0, 0, 0); if (i < 0) break; @@ -427,11 +442,11 @@ 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; @@ -455,6 +470,32 @@ int main(int argc, char *argv[]) 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; @@ -484,6 +525,16 @@ int main(int argc, char *argv[]) conf_parse(&sc); + /* --- Drop privileges --- */ + +#ifdef HAVE_SETGROUPS + if ((dropg != -1 && (setgid(dropg) || setgroups(1, &dropg))) || +#else + if ((dropg != -1 && setgid(dropg)) || +#endif + (drop != -1 && setuid(drop))) + die(1, "couldn't drop privileges: %s", strerror(errno)); + /* --- Fork into the background --- */ if (f & f_fork) { -- 2.11.0