A signal handler in sshd(8) may call a logging function that is not a…

…sync-

signal-safe.  The signal handler is invoked when a client does not
authenticate within the LoginGraceTime seconds (120 by default).  This signal
handler executes in the context of the sshd(8)'s privileged code, which is
not sandboxed and runs with full root privileges.

This issue is another instance of the problem in CVE-2024-6387 addressed by
FreeBSD-SA-24:04.openssh.  The faulty code in this case is from the
integration of blacklistd in OpenSSH

Obtained from: FreeBSD

crypto/openssh/sshd.c

@@ -377,8 +377,6 @@ grace_alarm_handler(int sig)
 		kill(0, SIGTERM);
 	}
 
-	BLACKLIST_NOTIFY(the_active_state, BLACKLIST_AUTH_FAIL, "ssh");
-
 	/* Log error and exit. */
 	sigdie("Timeout before authentication for %s port %d",
 	    ssh_remote_ipaddr(the_active_state),