From 504e7918d2329aa98953c0d1f76abdbdf184b3a5 Mon Sep 17 00:00:00 2001
From: Colin Petrie <cpetrie@ripe.net>
Date: Thu, 18 Aug 2016 17:35:31 +0200
Subject: [PATCH] Description: Fix undefind sprintf usage Author: Christoph
 Biedl <debian.axhn@manchmal.in-ulm.de> Last-Update: 2016-07-18

    Documentation states appending to a buffer using
        sprintf (buf, "%s.foo", buf);
    results in undefined behaviour. Work around it.
---
 bgpdump.c | 7 ++++---
 util.c    | 4 ++--
 util.h    | 2 +-
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/bgpdump.c b/bgpdump.c
index 5b70386..a77158f 100644
--- a/bgpdump.c
+++ b/bgpdump.c
@@ -273,19 +273,20 @@ void process(BGPDUMP_ENTRY *entry) {
     char prefix[BGPDUMP_ADDRSTRLEN];
     char *bgp4mp_format;
     char *bgp4mp_subtype_format;
+    int len;
 	
 	date=gmtime(&entry->time);
 	time2str(date,time_str_fixed);
     
     if (mode == 1) {
         // Timestamp mode
-        sprintf(time_str, "%lld", (long long)entry->time);
+        len = sprintf(time_str, "%lld", (long long)entry->time);
     } else {
-        time2str(date,time_str);
+        len = time2str(date,time_str);
     }
     // Appending microseconds to time_str if needed
     if (entry->type == BGPDUMP_TYPE_ZEBRA_BGP_ET) {
-        sprintf(time_str, "%s.%06ld", time_str, entry->ms);
+        sprintf(time_str + len, ".%06ld", entry->ms);
     }
     
 	if (mode==0)
diff --git a/util.c b/util.c
index 84438dd..d6db86c 100644
--- a/util.c
+++ b/util.c
@@ -66,9 +66,9 @@ void err(const char *fmt, ...) { log(ERR, error); }
 void warn(const char *fmt, ...) { log(WARNING, warn); }
 void debug(const char *fmt, ...) { log(INFO, info); }
 
-void time2str(struct tm* date,char *time_str)
+int time2str(struct tm* date,char *time_str)
 {
-    sprintf(time_str, "%02d/%02d/%02d %02d:%02d:%02d", date->tm_mon+1, date->tm_mday, date->tm_year%100,
+    return sprintf(time_str, "%02d/%02d/%02d %02d:%02d:%02d", date->tm_mon+1, date->tm_mday, date->tm_year%100,
             date->tm_hour, date->tm_min, date->tm_sec);
 }
 
diff --git a/util.h b/util.h
index 9ebd6f7..a8cf95b 100644
--- a/util.h
+++ b/util.h
@@ -38,7 +38,7 @@ char *fmt_ipv4(BGPDUMP_IP_ADDRESS addr, char *buffer);
 char *fmt_ipv6(BGPDUMP_IP_ADDRESS addr, char *buffer);
 void test_fmt_ip(void);
 
-void time2str(struct tm* date,char *time_str);
+int time2str(struct tm* date,char *time_str);
 int int2str(uint32_t value, char* str);
 void test_utils(void);