Changeset 2859 in MondoRescue for branches/2.2.9/mindi-busybox/sysklogd/klogd.c

Timestamp:

Jul 26, 2011, 1:25:42 AM (13 years ago)

Author:

Bruno Cornec

Message:

• Update to upstream busybox 1.18.5

File:

• branches/2.2.9/mindi-busybox/sysklogd/klogd.c (modified) (1 diff)

branches/2.2.9/mindi-busybox/sysklogd/klogd.c

@@ -151 +151 @@
     klogd_open();
     openlog("kernel", 0, LOG_KERN);
+    /*
+     * glibc problem: for some reason, glibc changes LOG_KERN to LOG_USER
+     * above. The logic behind this is that standard
+     * http://pubs.opengroup.org/onlinepubs/9699919799/functions/syslog.html
+     * says the following about openlog and syslog:
+     * "LOG_USER
+     *  Messages generated by arbitrary processes.
+     *  This is the default facility identifier if none is specified."
+     *
+     * I believe glibc misinterpreted this text as "if openlog's
+     * third parameter is 0 (=LOG_KERN), treat it as LOG_USER".
+     * Whereas it was meant to say "if *syslog* is called with facility
+     * 0 in its 1st parameter without prior call to openlog, then perform
+     * implicit openlog(LOG_USER)".
+     *
+     * As a result of this, eh, feature, standard klogd was forced
+     * to open-code its own openlog and syslog implementation (!).
+     *
+     * Note that prohibiting openlog(LOG_KERN) on libc level does not
+     * add any security: any process can open a socket to "/dev/log"
+     * and write a string "<0>Voila, a LOG_KERN + LOG_EMERG message"
+     *
+     * Google code search tells me there is no widespread use of
+     * openlog("foo", 0, 0), thus fixing glibc won't break userspace.
+     *
+     * The bug against glibc was filed:
+     * bugzilla.redhat.com/show_bug.cgi?id=547000
+     */
 
     if (i)
         klogd_setloglevel(i);
 
-    bb_signals(BB_FATAL_SIGS, record_signo);
     signal(SIGHUP, SIG_IGN);
+    /* We want klogd_read to not be restarted, thus _norestart: */
+    bb_signals_recursive_norestart(BB_FATAL_SIGS, record_signo);
 
     syslog(LOG_NOTICE, "klogd started: %s", bb_banner);