Simulierter Bufferoverflow

#include <stdio.h>
#include <string.h>
char *
funktion (void) {
	return "Befehle im Datenbereich ausführbar";
}


int
main (void) {
	char datenbereich[1024];
	char *(*zeiger)(void);

	memcpy(datenbereich, funktion, 1024);
	zeiger = (char *(*)(void)) datenbereich;
	printf("%s", zeiger());
	return (0);
}

C:\MinGW\bin>c++ ulli.cpp
ulli.cpp: In function 'char* funktion()':
ulli.cpp:5:11: warning: deprecated conversion from string constant to 'char*'
ulli.cpp: In function 'int main()':
ulli.cpp:13:39: error: invalid conversion from 'char* (*)()' to 'const void*'
ulli.cpp:13:39: error:   initializing argument 2 of 'void* memcpy(void*, const v
oid*, size_t)'


C:\MinGW\bin>g++ ulli.cpp
ulli.cpp: In function 'char* funktion()':
ulli.cpp:5:11: warning: deprecated conversion from string constant to 'char*'
ulli.cpp: In function 'int main()':
ulli.cpp:13:39: error: invalid conversion from 'char* (*)()' to 'const void*'
ulli.cpp:13:39: error:   initializing argument 2 of 'void* memcpy(void*, const v
oid*, size_t)'


C:\MinGW\bin>gcc ulli.cpp
ulli.cpp: In function 'char* funktion()':
ulli.cpp:5:11: warning: deprecated conversion from string constant to 'char*'
ulli.cpp: In function 'int main()':
ulli.cpp:13:39: error: invalid conversion from 'char* (*)()' to 'const void*'
ulli.cpp:13:39: error:   initializing argument 2 of 'void* memcpy(void*, const v
oid*, size_t)'


C:\MinGW\bin>

$ gcc -Wall buffer.cpp -o buffer
buffer.cpp: In function ‘char* funktion()’:
buffer.cpp:10: warning: deprecated conversion from string constant to ‘char*’
buffer.cpp: In function ‘int main()’:
buffer.cpp:18: error: invalid conversion from ‘char* (*)()’ to ‘const void*’
buffer.cpp:18: error:   initializing argument 2 of ‘void* memcpy(void*, const void*, size_t)’


$ g++ -Wall buffer.c -o buffer
buffer.c: In function ‘char* funktion()’:
buffer.c:10: warning: deprecated conversion from string constant to ‘char*’
buffer.c: In function ‘int main()’:
buffer.c:18: error: invalid conversion from ‘char* (*)()’ to ‘const void*’
buffer.c:18: error:   initializing argument 2 of ‘void* memcpy(void*, const void*, size_t)’


$ gcc -Wall buffer.c -o buffer
$ ./buffer
Speicherzugriffsfehler