View File busybox-1.18.3-klogd.patch of Package busybox (Project Virtualization:Appliances:suse-sle11)
@@ -150,12 +150,41 @@ int klogd_main(int argc UNUSED_PARAM, ch
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
- bb_signals(BB_FATAL_SIGS, record_signo);
+ /* 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);