cppcheck 抱怨缓冲区被越界访问。为啥以及如何解决?
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【中文标题】cppcheck 抱怨缓冲区被越界访问。为啥以及如何解决?【英文标题】:cppcheck complains Buffer is accessed out of bounds. Why and how do I fix?cppcheck 抱怨缓冲区被越界访问。为什么以及如何解决? 【发布时间】:2016-03-30 07:13:24 【问题描述】:下面的代码重现。在这种情况下,cppcheck 报告越界错误是否正确?用memcpy在线报错。
#include <stdint.h>
#include <string.h>
#include <stdio.h>
typedef struct
uint32_t serial_number;
uint8_t software_version[15];
STATIC_HARDWARE_DATA;
typedef struct
uint16_t result_code;
uint8_t startup_type;
STATIC_HARDWARE_DATA payment_data;
MSG_DETAILS;
int main()
MSG_DETAILS msg = 0;
msg.result_code = 0;
msg.startup_type = 2;
msg.payment_data.serial_number = 0xAAAA;
// on line below cppcheck says: Buffer is accessed out of bounds
memcpy(msg.payment_data.software_version, "1.01A", 15);
printf("%s", msg.payment_data.software_version); // prints correct 1.01A
/* in memory msg.payment_data.software_version is:
'1', '.', '0', '1', 'A', '\0', '\0', '\0', '_', '\0', '_', 'n', '\0', 'a'
The characters on end of array are unexpected?
*/
【问题讨论】:
使用1.01A
的大小而不是15
【参考方案1】:
#include <stdint.h>
#include <string.h>
#include <stdio.h>
typedef struct
uint32_t serial_number;
uint8_t software_version[15];
STATIC_HARDWARE_DATA;
typedef struct
uint16_t result_code;
uint8_t startup_type;
STATIC_HARDWARE_DATA payment_data;
MSG_DETAILS;
int main()
MSG_DETAILS msg = 0;
msg.result_code = 0;
msg.startup_type = 2;
msg.payment_data.serial_number = 0xAAAA;
// on line below cppcheck says: Buffer is accessed out of bounds
memcpy(msg.payment_data.software_version, "1.01A", 6);//<-- size should be 6 including \0.
printf("%s", msg.payment_data.software_version); // prints correct 1.01A
/* in memory msg.payment_data.software_version is:
'1', '.', '0', '1', 'A', '\0', '\0', '\0', '_', '\0', '_', 'n', '\0', 'a'
The characters on end of array are unexpected?
*/
o/p:
rabi@rabi-VirtualBox:~/rabi/c$ gcc gg.c
rabi@rabi-VirtualBox:~/rabi/c$ ./a.out
1.01A
【讨论】:
【参考方案2】:字符串文字"1.01A"
为您提供了一个指向六个字符数组的指针,您尝试从中读取 15 个字符。由于您读取的数据越界,您就有未定义的行为,因为内容是不确定的。
【讨论】:
当然没想到出处。这就解释了数组中的奇怪字符。以上是关于cppcheck 抱怨缓冲区被越界访问。为啥以及如何解决?的主要内容,如果未能解决你的问题,请参考以下文章
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