Don't display formatted time if localtime() fails.

Avoids a crash in strftime() found with the afl fuzzer.
ok guenther@

diff --git a/usr.bin/kdump/ktrstruct.c b/usr.bin/kdump/ktrstruct.c
index 0391066..b218ee2 100644 (file)
--- a/usr.bin/kdump/ktrstruct.c
+++ b/usr.bin/kdump/ktrstruct.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: ktrstruct.c,v 1.8 2014/12/15 01:48:54 guenther Exp $  */
+/*     $OpenBSD: ktrstruct.c,v 1.9 2014/12/16 03:19:23 jsg Exp $       */
 
 /*-
  * Copyright (c) 1988, 1993
@@ -146,8 +146,11 @@ print_time(time_t t, int relative, int have_subsec)
 
        if (!relative) {
                tm = localtime(&t);
-               (void)strftime(timestr, sizeof(timestr), TIME_FORMAT, tm);
-               printf("<\"%s\">", timestr);
+               if (tm != NULL) {
+                       (void)strftime(timestr, sizeof(timestr), TIME_FORMAT,
+                           tm);
+                       printf("<\"%s\">", timestr);
+               }
        }
 }