https://github.com/gozeloglu/safe_strn
Safe string library for C language.
https://github.com/gozeloglu/safe_strn
buffer-overflow buffer-overflow-attack c c-string library string string-library
Last synced: 3 months ago
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Safe string library for C language.
- Host: GitHub
- URL: https://github.com/gozeloglu/safe_strn
- Owner: gozeloglu
- License: gpl-3.0
- Created: 2021-03-05T22:12:09.000Z (about 4 years ago)
- Default Branch: main
- Last Pushed: 2021-03-13T11:35:21.000Z (about 4 years ago)
- Last Synced: 2025-01-04T20:16:39.694Z (5 months ago)
- Topics: buffer-overflow, buffer-overflow-attack, c, c-string, library, string, string-library
- Language: C
- Homepage:
- Size: 33.2 KB
- Stars: 1
- Watchers: 2
- Forks: 0
- Open Issues: 2
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# safe_strn
safe_strn is a C library for safe string operation. It includes some basic string functions to prevent buffer overflow.
### Run
Firstly, compile the code with following command:
```shell
$ gcc lib/*.h lib/*.c test/*.h test/*.c example/*
```
Then, run the executable file.
```shell
$ ./a.out
```
### Usage
Add `lib/` folder under your workspace and include the library as follows. You may need to give the relative path depending on where you put location.
```c
#include "safe_string.h"
int main() {
char *src = "hello world";
char *new_str = (char *) malloc(sizeof(char) * 12); // Allocate memory for string
str_cpy(src, new_str, 11); // Copy src to new_str
int len = str_len(new_str); // Length of new_str
char *str1 = "abc";
char *str2 = "abc";
int res = str_cmp(str1, str2, 3, 3);
if (res < 0) {
printf("str1 less than str2\n"):
} else if (res > 0){
printf("str2 less than str1.\n");
} else {
printf("str1 and str2 are equal.\n"); // Prints "str1 and str2 are equal."
}
char *str = str_mk("create a new string.", 50); // Create a null-terminated string with maximum 50 length.
}
```
### Documentation
### `str_mk`
Creates string by preventing potential buffer overflow. Guarantees putting null-terminator at the end of the string. Also, prevents buffer overflow which is caused by integer overflow.
```c
char *str_mk(const char *str, size_t str_len);
```
### `str_cpy`
Copies the string from `src` to `dst`. You need to pass length of the string that you want to copy.
```C
int str_cpy(const char *src, char *dst, size_t n));
```
### `str_len`
Returns the length of the string.
```C
int str_len(const char *s);
```
### `str_cat`
Concatenates the given strings. Returns the new length of the `src`.
```C
int str_cat(char *src, const char *append, size_t src_size, size_t app_size);
```
### `str_cmp`
Compares the two given strings. If `str1` less than `str2`, returns -1. If `str2` less than `str1`, returns 1. And `str1` and `str2` are equal, then returns 0.
```c
int str_cmp(const char *str1, const char *str2, size_t str1_size, size_t str2_size);
```
## LICENSE
[GNU General Public License v3.0](https://github.com/gozeloglu/safe_strn/blob/main/LICENSE)