Edit strings in binary files

stredit.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[]){
    FILE * f = fopen(argv[1], "rb+");
    fseek(f, 0, SEEK_END);
    unsigned long long int size = ftell(f);
    fseek(f, 0, SEEK_SET);
    unsigned char *data = (unsigned char *)malloc(size);
    fread(data, 1, size, f);
    size_t old_len = strlen(argv[2]), new_len = strlen(argv[3]);
    for (unsigned long long int i=0; i<size-old_len; i++) {
        if(!memcmp(&data[i], argv[2], old_len)) {
            memmove(&data[i+new_len], &data[i+old_len], size-(i+old_len));
            memcpy(&data[i], argv[3], new_len);
            break;
        }
    }
    fseek(f, 0, SEEK_SET);
    fwrite(data, 1, size, f);
    fclose(f);
    free(data);
    return 0;
}

/*

USAGE: stredit file.bin "old string" "new string" 
COMPILE & SETUP: gcc stredit.c -o stredit && sudo cp stredit /usr/local/bin/stredit

*/