Snort mailing list archives
Re: snort 2.9.0.4 won't daemonize, OpenBSD 4.7
From: Olaf Schreck <chakl () syscall de>
Date: Fri, 08 Apr 2011 22:51:59 +0200
Replying to self with a workaround solution, for the archives
snort 2.9.0.4 on OpenBSD 4.7, running fine, but won't daemonize.
Is anyone running snort 2.9 on OpenBSD 4.7 or 4.8 who does NOT have this problem? I had a look at the daemonize code in util.c and rebuilt snort with "CPPFLAGS=-DDEBUG sh configure.sh ..." to see the debug messages. As expected, the daemon parent waits for a "child ready" signal that never arrives while the daemon child claims to have sent it. Signal is SIGCONT as defined in snort.h: #define SIGNAL_SNORT_CHILD_READY 29 So for some obscure reason, the daemon parent does not see SIGCONT from the daemon child. In the OpenBSD manpage for kill(2) I noticed Setuid and setgid processes are dealt with slightly differently. For the non-root user, to prevent attacks against such processes, some signal deliveries are not permitted and return the error EPERM. The following signals are allowed through to this class of processes: SIGKILL, SIGINT, SIGTERM, SIGSTOP, SIGTTIN, SIGTTOU, SIGTSTP, SIGHUP, SIGUSR1, SIGUSR2. Since SIGCONT was not mentioned in the list above, I tried changing the "child-ready" signal to SIGUSR2: #define SIGNAL_SNORT_CHILD_READY 31 Works fine as expected. And no, I did not specify setuid/setgid on the command line or in snort.conf, and ran it as root. I have no idea why SIGCONT is filtered here, but SIGUSR2 is not.
At the end of the startup messages it says: Spawning daemon child... My daemon child 3777 lives... 0x8151dc00*running 15 -c-------f 0000 main but it doesn't come back to the shell prompt. I can ^C out and see the snort child process. With ^Z, I see 2 snort processes. Obviously the parent won't exit while daemonizing. Any clues why? The daemonized child runs and alerts just fine. This happens regardless whether I use -D on the cmdline, "config daemon" in snort.conf, or both.
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Current thread:
- Re: snort 2.9.0.4 won't daemonize, OpenBSD 4.7 Olaf Schreck (Apr 08)
- Re: snort 2.9.0.4 won't daemonize, OpenBSD 4.7 Joel Esler (Apr 08)