Update main.c

2021/HotelCodeifornia/main.c

@@ -1,90 +1 @@
-#include <openssl/rsa.h>
-#include <openssl/crypto.h>
-#include <openssl/sha.h>
-#include <openssl/pem.h>
-#include <openssl/bio.h>
-#include <stdio.h>
-#include <gmp.h>
-#include <stdint.h>
-#include <string.h>
-
-int verify_sig(char* data, char* sigin) {
-
-    // read RSA file
-    FILE *f = fopen("pubkey.pem", "r");
-    fseek(f, 0, SEEK_END);
-    size_t size = (size_t)ftell(f);
-    rewind(f);
-
-    uint8_t *key = malloc(size);
-
-    fread(key, sizeof(uint8_t), size, f);
-    fclose(f);
-
-    // read key
-    BIO* bo = BIO_new(BIO_s_mem());
-    BIO_write(bo, key, strlen(key));
-
-    EVP_PKEY* pkey = 0;
-    RSA* keypair;
-    keypair = RSA_new();
-    PEM_read_bio_RSA_PUBKEY(bo, &keypair, 0, 0);
-
-    BIO_free(bo);
-
-    uint8_t digest[SHA256_DIGEST_LENGTH];
-
-    SHA256_CTX ctx;
-
-    if (!SHA256_Init(&ctx) || !SHA256_Update(&ctx, data, strlen(data)) || !SHA256_Final(digest, &ctx)) {
-        printf("Error verifying signature.");
-        free(data);
-        return 0;
-    }
-
-    mpz_t sig, e, n;
-    mpz_inits(sig, e, n, NULL);
-
-    mpz_set_str(sig, sigin, 16);
-    mpz_set_str(e, BN_bn2hex(keypair->e), 16);
-    mpz_set_str(n, BN_bn2hex(keypair->n), 16);
-
-    mpz_powm(sig, sig, e, n);
-
-
-    size_t bytes;
-    uint8_t* export = mpz_export(NULL, NULL, 0, sizeof(uint8_t), 0, 0, sig);
-
-    mpz_clears(sig, e, n, NULL);
-
-    return strncmp((char*)export, digest, SHA256_DIGEST_LENGTH) == 0;
-}
-
-int main(int argc, char *argv[]) {
-    setvbuf(stdout, NULL, _IONBF, 0);
-    setvbuf(stdin, NULL, _IONBF, 0);
-    setvbuf(stderr, NULL, _IONBF, 0);
-
-    printf("       Welcome to the Hotel Codeifornia\n");
-    printf("Esteemed secure code execution service since 1969\n\n");
-    printf("If you have a booking, please sign the guestbook below.\n");
-
-    char code[255];
-    printf("Enter code> ");
-    fgets(code,255,stdin);
-    code[strlen(code)-1] = '\0';
-
-    char sig[1024];
-    printf("And just sign here please, sir> ");
-    fgets(sig,1024,stdin);
-    sig[strlen(sig)-1] = '\0';
-
-    if(verify_sig(code, sig)) {
-        char exec[300];
-        sprintf(exec, "python3 -c '%s'", code);
-        printf("\n");
-        system(exec);
-    } else {
-        printf("\nI'm sorry, sir, but you don't appear to be on the guestbook.\n");
-    }
-}
+// challenge being kept private :)