From a7476dd96e79197f65acf0f049f75ce8e8f9e801 Mon Sep 17 00:00:00 2001
From: Jan Pokorny <jpokorny@redhat.com>
Date: Thu, 2 Feb 2017 14:51:46 +0100
Subject: [PATCH] Fix: crm_mon: protect against non-standard or failing asctime

So far, we have been likely covered by standards requiring asctime to
produce an output ending with \n\0 bytes, because otherwise, we would
overrun the buffer, reading unspecified content, possibly segfaulting.
This was actually discovered with a brand new GCC7 warning
( [-Werror=pointer-compare]).

Another latent issue was that the code was not ready for the case
of failing asctime call (returning NULL).  This is now fixed as well.
---
 tools/crm_mon.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/crm_mon.c b/tools/crm_mon.c
index 776aea8..023b07b 100644
--- a/tools/crm_mon.c
+++ b/tools/crm_mon.c
@@ -954,10 +954,10 @@ print_nvpair(FILE *stream, const char *name, const char *value,
 
     /* Otherwise print user-friendly time string */
     } else {
-        char *date_str, *c;
+        static char empty_str[] = "";
+        char *c, *date_str = asctime(localtime(&epoch_time));
 
-        date_str = asctime(localtime(&epoch_time));
-        for (c = date_str; c != '\0'; ++c) {
+        for (c = (date_str != NULL) ? date_str : empty_str; *c != '\0'; ++c) {
             if (*c == '\n') {
                 *c = '\0';
                 break;
-- 
1.8.3.1