NetBSD Problem Report #27309

From gnats-bugs-owner-gnats=mail-index.netbsd.org@gnats.NetBSD.org  Thu Oct 21 15:07:57 2004
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Message-Id: <20041021150755.4370E548E98@dogfish-head.cs.stevens.edu>
Date: Thu, 21 Oct 2004 11:07:55 -0400 (EDT)
From: jschauma@stevens-tech.edu
Reply-To: jschauma@stevens-tech.edu
To: gnats-bugs@gnats.NetBSD.org
Subject: syslogd -u can't create pidfile
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>Number:         27309
>Category:       bin
>Synopsis:       syslogd -u can't create pidfile
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Oct 22 08:47:01 +0000 2004
>Closed-Date:    Sat Nov 09 16:17:20 +0000 2024
>Last-Modified:  Sat Nov 09 16:17:20 +0000 2024
>Originator:     Jan Schaumann
>Release:        NetBSD 2.0_RC3
>Organization:

>Environment:


System: NetBSD dogfish-head.cs.stevens.edu 2.0_RC3 NetBSD 2.0_RC3 (BOCK) #20: Mon Oct 4 14:19:22 EDT 2004 jschauma@doppelbock.hpcf.cs.stevens-tech.edu:/share/src/sys/arch/i386/compile/obj/BOCK i386
Architecture: i386
Machine: i386
>Description:
	When starting syslogd(8) with the '-u' option, syslogd will be unable
	to create the standard pidfile, as it changes UID and the user likely
	does not have write permission to /var/run/.
>How-To-Repeat:
	Add:

	syslogd=YES
	syslogd_flags="-u syslogd -g syslogd"

	to /etc/rc.conf

	/etc/rc.d/syslogd restart
	syslogd not running? (check /var/run/syslogd.pid).
	Starting syslogd.

	ls /var/run/syslogd.pid
	ls: /var/run/syslogd.pid: No such file or directory

	ps ax | grep sysl
	 8461 ?? Ss     0:00.00 /usr/sbin/syslogd -u syslogd -g syslogd

	/etc/rc.d/syslogd restart
	syslogd not running? (check /var/run/syslogd.pid).
	Starting syslogd.
	syslogd: bind() failed: Address already in use
	syslogd: Fatal error, exiting


>Fix:

	Well, create pidfile before changing UID.  However, there seems
	to be a problem:  syslogd.c around #464 indicates that we can't
	daemonize until we're sure we don't get any fatal errors.  So we
	can't daemonize until we've changed UID.  We can't create the pidfile
	before daemonizing, obviously, either.

>Release-Note:
>Audit-Trail:
From: Jan Schaumann <jschauma@netmeister.org>
To: gnats-bugs@netbsd.org
Cc: 
Subject: Re: bin/27309
Date: Thu, 7 Nov 2024 21:36:23 -0500

 Stumbling upon this old bug from (double-checks
 creation date) 20 years ago, I figured I'd take a stab
 at addressing it:


 Index: syslogd.c
 ===================================================================
 RCS file: /cvsroot/src/usr.sbin/syslogd/syslogd.c,v
 retrieving revision 1.145
 diff -u -p -b -u -r1.145 syslogd.c
 --- syslogd.c	8 Nov 2024 02:23:54 -0000	1.145
 +++ syslogd.c	8 Nov 2024 02:30:20 -0000
 @@ -316,6 +316,7 @@ main(int argc, char *argv[])
  	struct group   *gr;
  	struct passwd  *pw;
  	unsigned long l;
 ++	char pfpath[PATH_MAX];

  	/* should we set LC_TIME="C" to ensure correct timestamps&parsing? */
  	(void)setlocale(LC_ALL, "");
 @@ -564,6 +565,33 @@ getgroup:
  	    LOG_NFACILITIES, IETF_NUM_PRIVALUES>>3);
  #endif

 +#ifdef __NetBSD_Version__
 +	if ((uid != 0) || (gid != 0)) {
 +		/* Create the pidfile here so we can chown it to the target
 +		 * user/group and possibly report any error before daemonizing.
 +		 * We then call pidfile(3) again to write the actual
 +		 * daemon pid below.
 +		 *
 +		 * Note: this will likely leave the truncated pidfile in
 +		 * place upon exit, since the effective user is unlikely
 +		 * to have write permissions to _PATH_VARRUN. */
 +		if (pidfile(NULL)) {
 +			logerror("Failed to create pidfile");
 +			die(0, 0, NULL);
 +		}
 +		l = sizeof(pfpath);
 +		if ((size_t)snprintf(pfpath, l, "%s%s.pid",
 +					_PATH_VARRUN, getprogname()) >= l) {
 +			logerror("Pidfile path `%s' too long.", pfpath);
 +			die(0, 0, NULL);
 +		}
 +		if (chown(pfpath, uid, gid) < 0) {
 +			logerror("Failed to chown pidfile `%s` to `%d:%d`", pfpath, uid, gid);
 +			die(0, 0, NULL);
 +		}
 +	}
 +#endif /* __NetBSD_Version__ */
 +
  	/*
  	 * All files are open, we can drop privileges and chroot.
  	 */

State-Changed-From-To: open->closed
State-Changed-By: jschauma@NetBSD.org
State-Changed-When: Sat, 09 Nov 2024 16:17:20 +0000
State-Changed-Why:
Fixed in rev1.146 of syslogd.c.


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