.\" -*-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
.\"
.\" ---- 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.
.\"
.RB [ \-dlq ]
.RB [ \-f
.IR file ]
+.RB [ \-s
+.IR user ]
+.RB [ \-g
+.IR group ]
.IR config-stmt ...
.
.\"--------------------------------------------------------------------------
.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 .
.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
/* -*-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
*
/*----- 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.
*
#include <unistd.h>
#include <syslog.h>
+#include <grp.h>
+#include <pwd.h>
+
#include <mLib/bres.h>
#include <mLib/dstr.h>
#include <mLib/mdwopt.h>
-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\
sel_state sst;
sig s_term, s_int;
scanner sc;
+ uid_t drop = -1;
+ gid_t dropg = -1;
enum {
f_bogus = 1,
{ "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;
usage(stdout);
exit(0);
break;
- case 'g':
+ case 'G':
grammar(stdout);
exit(0);
break;
- case 'o':
+ case 'O':
options(stdout);
exit(0);
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;
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) {