ms_funcs.c

Go to the documentation of this file.

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

#include "common.h"
#include "sha1.h"
#include "ms_funcs.h"
#include "crypto.h"
#include "rc4.h"


static void challenge_hash(const u8 *peer_challenge, const u8 *auth_challenge,
                           const u8 *username, size_t username_len,
                           u8 *challenge)
{
        u8 hash[SHA1_MAC_LEN];
        const unsigned char *addr[3];
        size_t len[3];

        addr[0] = peer_challenge;
        len[0] = 16;
        addr[1] = auth_challenge;
        len[1] = 16;
        addr[2] = username;
        len[2] = username_len;

        sha1_vector(3, addr, len, hash);
        memcpy(challenge, hash, 8);
}


void nt_password_hash(const u8 *password, size_t password_len,
                      u8 *password_hash)
{
        u8 buf[512], *pos;
        size_t i, len;

        if (password_len > 256)
                return;

        /* Convert password into unicode */
        for (i = 0; i < password_len; i++) {
                buf[2 * i] = password[i];
                buf[2 * i + 1] = 0;
        }

        len = password_len * 2;
        pos = buf;
        md4_vector(1, (const u8 **) &pos, &len, password_hash);
}


void hash_nt_password_hash(const u8 *password_hash, u8 *password_hash_hash)
{
        size_t len = 16;
        md4_vector(1, &password_hash, &len, password_hash_hash);
}


void challenge_response(const u8 *challenge, const u8 *password_hash,
                        u8 *response)
{
        u8 zpwd[7];
        des_encrypt(challenge, password_hash, response);
        des_encrypt(challenge, password_hash + 7, response + 8);
        zpwd[0] = password_hash[14];
        zpwd[1] = password_hash[15];
        memset(zpwd + 2, 0, 5);
        des_encrypt(challenge, zpwd, response + 16);
}


void generate_nt_response(const u8 *auth_challenge, const u8 *peer_challenge,
                          const u8 *username, size_t username_len,
                          const u8 *password, size_t password_len,
                          u8 *response)
{
        u8 challenge[8];
        u8 password_hash[16];

        challenge_hash(peer_challenge, auth_challenge, username, username_len,
                       challenge);
        nt_password_hash(password, password_len, password_hash);
        challenge_response(challenge, password_hash, response);
}


void generate_authenticator_response(const u8 *password, size_t password_len,
                                     const u8 *peer_challenge,
                                     const u8 *auth_challenge,
                                     const u8 *username, size_t username_len,
                                     const u8 *nt_response, u8 *response)
{
        static const u8 magic1[39] = {
                0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
                0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
                0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
                0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74
        };
        static const u8 magic2[41] = {
                0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
                0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
                0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
                0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
                0x6E
        };

        u8 password_hash[16], password_hash_hash[16], challenge[8];
        const unsigned char *addr1[3];
        const size_t len1[3] = { 16, 24, sizeof(magic1) };
        const unsigned char *addr2[3];
        const size_t len2[3] = { SHA1_MAC_LEN, 8, sizeof(magic2) };

        addr1[0] = password_hash_hash;
        addr1[1] = nt_response;
        addr1[2] = magic1;

        addr2[0] = response;
        addr2[1] = challenge;
        addr2[2] = magic2;

        nt_password_hash(password, password_len, password_hash);
        hash_nt_password_hash(password_hash, password_hash_hash);
        sha1_vector(3, addr1, len1, response);

        challenge_hash(peer_challenge, auth_challenge, username, username_len,
                       challenge);
        sha1_vector(3, addr2, len2, response);
}


void nt_challenge_response(const u8 *challenge, const u8 *password,
                           size_t password_len, u8 *response)
{
        u8 password_hash[16];
        nt_password_hash(password, password_len, password_hash);
        challenge_response(challenge, password_hash, response);
}


void get_master_key(const u8 *password_hash_hash, const u8 *nt_response,
                    u8 *master_key)
{
        static const u8 magic1[27] = {
                0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
                0x68, 0x65, 0x20, 0x4d, 0x50, 0x50, 0x45, 0x20, 0x4d,
                0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x4b, 0x65, 0x79
        };
        const unsigned char *addr[3];
        const size_t len[3] = { 16, 24, sizeof(magic1) };
        u8 hash[SHA1_MAC_LEN];

        addr[0] = password_hash_hash;
        addr[1] = nt_response;
        addr[2] = magic1;

        sha1_vector(3, addr, len, hash);
        memcpy(master_key, hash, 16);
}


void get_asymetric_start_key(const u8 *master_key, u8 *session_key,
                             size_t session_key_len, int is_send,
                             int is_server)
{
        static const u8 magic2[84] = {
                0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
                0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
                0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
                0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20, 0x6b, 0x65, 0x79,
                0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
                0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x69, 0x64, 0x65,
                0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
                0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
                0x6b, 0x65, 0x79, 0x2e
        };
        static const u8 magic3[84] = {
                0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
                0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
                0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
                0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
                0x6b, 0x65, 0x79, 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68,
                0x65, 0x20, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73,
                0x69, 0x64, 0x65, 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73,
                0x20, 0x74, 0x68, 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20,
                0x6b, 0x65, 0x79, 0x2e
        };
        static const u8 shs_pad1[40] = {
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
                0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
        };

        static const u8 shs_pad2[40] = {
                0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
                0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
                0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
                0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2
        };
        u8 digest[SHA1_MAC_LEN];
        const unsigned char *addr[4];
        const size_t len[4] = { 16, 40, 84, 40 };

        addr[0] = master_key;
        addr[1] = shs_pad1;
        if (is_send) {
                addr[2] = is_server ? magic3 : magic2;
        } else {
                addr[2] = is_server ? magic2 : magic3;
        }
        addr[3] = shs_pad2;

        sha1_vector(4, addr, len, digest);

        if (session_key_len > SHA1_MAC_LEN)
                session_key_len = SHA1_MAC_LEN;
        memcpy(session_key, digest, session_key_len);
}


#define PWBLOCK_LEN 516

static void encrypt_pw_block_with_password_hash(
        const u8 *password, size_t password_len,
        const u8 *password_hash, u8 *pw_block)
{
        size_t i, offset;
        u8 *pos;

        if (password_len > 256)
                return;

        memset(pw_block, 0, PWBLOCK_LEN);
        offset = (256 - password_len) * 2;
        hostapd_get_rand(pw_block, offset);
        for (i = 0; i < password_len; i++)
                pw_block[offset + i * 2] = password[i];
        /*
         * PasswordLength is 4 octets, but since the maximum password length is
         * 256, only first two (in little endian byte order) can be non-zero.
         */
        pos = &pw_block[2 * 256];
        WPA_PUT_LE16(pos, password_len * 2);
        rc4(pw_block, PWBLOCK_LEN, password_hash, 16);
}


void new_password_encrypted_with_old_nt_password_hash(
        const u8 *new_password, size_t new_password_len,
        const u8 *old_password, size_t old_password_len,
        u8 *encrypted_pw_block)
{
        u8 password_hash[16];

        nt_password_hash(old_password, old_password_len, password_hash);
        encrypt_pw_block_with_password_hash(new_password, new_password_len,
                                            password_hash, encrypted_pw_block);
}


static void nt_password_hash_encrypted_with_block(const u8 *password_hash,
                                                  const u8 *block,
                                                  u8 *cypher)
{
        des_encrypt(password_hash, block, cypher);
        des_encrypt(password_hash + 8, block + 7, cypher + 8);
}


void old_nt_password_hash_encrypted_with_new_nt_password_hash(
        const u8 *new_password, size_t new_password_len,
        const u8 *old_password, size_t old_password_len,
        u8 *encrypted_password_hash)
{
        u8 old_password_hash[16], new_password_hash[16];

        nt_password_hash(old_password, old_password_len, old_password_hash);
        nt_password_hash(new_password, new_password_len, new_password_hash);
        nt_password_hash_encrypted_with_block(old_password_hash,
                                              new_password_hash,
                                              encrypted_password_hash);
}


#ifdef TEST_MAIN_MS_FUNCS

#include "rc4.c"

int main(int argc, char *argv[])
{
        /* Test vector from RFC2759 example */
        u8 *username = "User";
        u8 *password = "clientPass";
        u8 auth_challenge[] = {
                0x5B, 0x5D, 0x7C, 0x7D, 0x7B, 0x3F, 0x2F, 0x3E,
                0x3C, 0x2C, 0x60, 0x21, 0x32, 0x26, 0x26, 0x28
        };
        u8 peer_challenge[] = {
                0x21, 0x40, 0x23, 0x24, 0x25, 0x5E, 0x26, 0x2A,
                0x28, 0x29, 0x5F, 0x2B, 0x3A, 0x33, 0x7C, 0x7E
        };
        u8 challenge[] = { 0xD0, 0x2E, 0x43, 0x86, 0xBC, 0xE9, 0x12, 0x26 };
        u8 password_hash[] = {
                0x44, 0xEB, 0xBA, 0x8D, 0x53, 0x12, 0xB8, 0xD6,
                0x11, 0x47, 0x44, 0x11, 0xF5, 0x69, 0x89, 0xAE
        };
        u8 nt_response[] = {
                0x82, 0x30, 0x9E, 0xCD, 0x8D, 0x70, 0x8B, 0x5E,
                0xA0, 0x8F, 0xAA, 0x39, 0x81, 0xCD, 0x83, 0x54,
                0x42, 0x33, 0x11, 0x4A, 0x3D, 0x85, 0xD6, 0xDF
        };
        u8 password_hash_hash[] = {
                0x41, 0xC0, 0x0C, 0x58, 0x4B, 0xD2, 0xD9, 0x1C,
                0x40, 0x17, 0xA2, 0xA1, 0x2F, 0xA5, 0x9F, 0x3F
        };
        u8 authenticator_response[] = {
                0x40, 0x7A, 0x55, 0x89, 0x11, 0x5F, 0xD0, 0xD6,
                0x20, 0x9F, 0x51, 0x0F, 0xE9, 0xC0, 0x45, 0x66,
                0x93, 0x2C, 0xDA, 0x56
        };
        u8 master_key[] = {
                0xFD, 0xEC, 0xE3, 0x71, 0x7A, 0x8C, 0x83, 0x8C,
                0xB3, 0x88, 0xE5, 0x27, 0xAE, 0x3C, 0xDD, 0x31
        };
        u8 send_start_key[] = {
                0x8B, 0x7C, 0xDC, 0x14, 0x9B, 0x99, 0x3A, 0x1B,
                0xA1, 0x18, 0xCB, 0x15, 0x3F, 0x56, 0xDC, 0xCB
        };
        u8 buf[32];

        int errors = 0;

        printf("Testing ms_funcs.c\n");

        challenge_hash(peer_challenge, auth_challenge,
                       username, strlen(username),
                       buf);
        if (memcmp(challenge, buf, sizeof(challenge)) != 0) {
                printf("challenge_hash failed\n");
                errors++;
        }

        nt_password_hash(password, strlen(password), buf);
        if (memcmp(password_hash, buf, sizeof(password_hash)) != 0) {
                printf("nt_password_hash failed\n");
                errors++;
        }

        generate_nt_response(auth_challenge, peer_challenge,
                             username, strlen(username),
                             password, strlen(password),
                             buf);
        if (memcmp(nt_response, buf, sizeof(nt_response)) != 0) {
                printf("generate_nt_response failed\n");
                errors++;
        }

        hash_nt_password_hash(password_hash, buf);
        if (memcmp(password_hash_hash, buf, sizeof(password_hash_hash)) != 0) {
                printf("hash_nt_password_hash failed\n");
                errors++;
        }

        generate_authenticator_response(password, strlen(password),
                                        peer_challenge, auth_challenge,
                                        username, strlen(username),
                                        nt_response, buf);
        if (memcmp(authenticator_response, buf, sizeof(authenticator_response))
            != 0) {
                printf("generate_authenticator_response failed\n");
                errors++;
        }

        get_master_key(password_hash_hash, nt_response, buf);
        if (memcmp(master_key, buf, sizeof(master_key)) != 0) {
                printf("get_master_key failed\n");
                errors++;
        }

        get_asymetric_start_key(master_key, buf, sizeof(send_start_key), 1, 1);
        if (memcmp(send_start_key, buf, sizeof(send_start_key)) != 0) {
                printf("get_asymetric_start_key failed\n");
                errors++;
        }

        if (errors)
                printf("FAILED! %d errors\n", errors);

        return errors;
}
#endif /* TEST_MAIN_MS_FUNCS */

---