Rather than using syslog(3) (which pulls in snprintf), creating the report

string using simpler strings functions and use sendsyslog2() directly.
Also, use the LOG_CONS flag so that single-user reports are more clear.
Use a buffer size of 1024 (from bluhm)
discussed with guenther and matthew
ok millert

1 files changed, 14 insertions, 4 deletions

diff --git a/lib/libc/sys/stack_protector.c b/lib/libc/sys/stack_protector.c
index e61a5f2f82f..b7d9a364ae2 100644
--- a/lib/libc/sys/stack_protector.c
+++ b/lib/libc/sys/stack_protector.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: stack_protector.c,v 1.19 2015/11/10 04:30:59 guenther Exp $	*/
+/*	$OpenBSD: stack_protector.c,v 1.20 2015/11/25 00:16:40 deraadt Exp $	*/
 
 /*
  * Copyright (c) 2002 Hiroaki Etoh, Federico G. Schwindt, and Miodrag Vallat.
@@ -49,17 +49,27 @@ long __guard_local __dso_hidden __attribute__((section(".openbsd.randomdata")));
 void
 __stack_smash_handler(const char func[], int damaged)
 {
-	struct syslog_data sdata = SYSLOG_DATA_INIT;
-	const char message[] = "stack overflow in function %s";
+	extern char *__progname;
 	struct sigaction sa;
 	sigset_t mask;
+	char buf[1024];
+	size_t len;
 
 	/* Immediately block all signal handlers from running code */
 	sigfillset(&mask);
 	sigdelset(&mask, SIGABRT);
 	sigprocmask(SIG_SETMASK, &mask, NULL);
 
-	syslog_r(LOG_CRIT, &sdata, message, func);
+	/* <10> is LOG_CRIT */
+	len = strlcpy(buf, "<10>", sizeof buf);
+	strlcpy(buf + len, __progname, sizeof buf - len);
+
+	/* truncate progname in case it is too long */
+	buf[sizeof(buf) / 2] = '\0';
+	strlcat(buf, ": stack overflow in function ", sizeof buf);
+	strlcat(buf, func, sizeof buf);
+
+	sendsyslog2(buf, strlen(buf), LOG_CONS);
 
 	memset(&sa, 0, sizeof(sa));
 	sigemptyset(&sa.sa_mask);