1 #include <stdlib.h>
2 #include <unistd.h>
3 #include <sys/syscall.h>
4 
main(void)5 int main(void)
6 {
7    // uninitialised, but we know pi[0] is 0x0
8    int* pi  = malloc(sizeof(int));
9 
10    // uninitialised, but we know pc[0] points to 0x0
11    char** pc  = malloc(sizeof(char*));
12 
13    // Five errors:
14    // - the syscall number itself is undefined (but we know it's
15    //   0 + __NR_write :)
16    // - each of the scalar args are undefined
17    // - the 2nd arg points to unaddressable memory.
18    syscall(pi[0]+__NR_write, pi[0], pc[0], pi[0]+1);
19 
20    return 0;
21 }
22 
23