1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
From aa2ce32185b4477e659ed7c70d09c440610ef67b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20P=C3=ADsa=C5=99?= <ppisar@redhat.com>
Date: Fri, 2 Feb 2018 12:44:15 +0100
Subject: [PATCH] Fix buffer size when formatting current date
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
gcc-8 and glibc-2.26.9000 reports this error:
server/log.c:64:54: error: '%03d' directive output may be truncated writing between 3 and 11 bytes into a region of size between 0 and 49 [-Werror=format-truncation=]
snprintf(current_date, sizeof(current_date), "%s.%03d", buf, (int)(1000 * (time-seconds)));
^~~~
This patch fixes two mistakes in the get_current_date() function:
First strftime() can fail and then buf content is undefined. The patch
makes sure the buf content is properly null-termited.
Second if strftime() uses up the the whole buf array, no space will be
left for appending miliseconds to current_date value in the subsequent
snprintf() call. The patch increases current_data size so that things
will always fit.
In reality, all this should not matter because sane strftime() will
return fixed-lenght string. But for all the cases and for sake of the
compiler check this patch should be applied.
Signed-off-by: Petr Písař <ppisar@redhat.com>
---
server/log.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/server/log.c b/server/log.c
index 2fe7b7c..f696752 100644
--- a/server/log.c
+++ b/server/log.c
@@ -52,15 +52,17 @@ double get_current_time_exact(void)
return (double) now.tv_sec + now.tv_usec / 1e6; // bad bad idea to use float as precision is not down to the seconds then
}
-char current_date[50];
+char current_date[70];
char* get_current_date(void)
{
struct tm * lt;
char buf[50];
double time = get_current_time_exact();
time_t seconds = (time_t)time;
+ size_t length;
lt = localtime(&seconds);
- strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", lt);
+ length = strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", lt);
+ buf[length] = '\0';
snprintf(current_date, sizeof(current_date), "%s.%03d", buf, (int)(1000 * (time-seconds)));
return current_date;
}
diff -up frozen-bubble-2.2.1-beta1/server/log.h~ frozen-bubble-2.2.1-beta1/server/log.h
--- frozen-bubble-2.2.1-beta1/server/log.h~ 2010-08-07 15:36:27.000000000 +0200
+++ frozen-bubble-2.2.1-beta1/server/log.h 2018-02-08 14:09:52.472451694 +0100
@@ -23,7 +23,7 @@
time_t get_current_time(void);
double get_current_time_exact(void);
-extern char current_date[50];
+extern char current_date[70];
char* get_current_date(void);
enum output_types { OUTPUT_TYPE_DEBUG, OUTPUT_TYPE_CONNECT, OUTPUT_TYPE_INFO, OUTPUT_TYPE_ERROR };
|