Merge pull request #527 from naemon/remove_tv_str_light

Fix memory corruption in mkstr caused by integer overflow

Author: nook24

NEWS

@@ -5,6 +5,9 @@ Breaking changes:
 Features:
 * new attribute 'check_timeout' on `host` and `service` structs, overrides the global host / service check timeouts. (#525)
 
+Bugfixes:
+* fix memory corruption in `mkstr` caused by integer overflow (#527)
+
 1.5.0 - Feb 03 2026
 ===================
 Breaking changes:

lib/nsutils.c

@@ -70,7 +70,7 @@ float tv_delta_f(const struct timeval *start, const struct timeval *stop)
 
 /* format duration seconds into human readable string */
 const char* tv_str(struct timeval *tv) {
-	return (char *)mkstr("%lu.%06lu", tv->tv_sec, tv->tv_usec);
+	return (char *)mkstr("%lld.%06ld", (long long)tv->tv_sec, (long)tv->tv_usec);
 }
 
  /* Convert string to timeval */
@@ -94,7 +94,7 @@ int str2timeval(char *str, struct timeval *tv)
 const char *mkstr(const char *fmt, ...)
 {
 	static char buf[MKSTR_BUFS][32]; /* 8k statically on the stack */
-	static int slot = 0;
+	static unsigned int slot = 0;
 	char *ret;
 
 	va_list ap;