WHATSNEW: SMB3 Directory Leases

[Samba.git] / libcli / auth / smbencrypt.c

/*
   Unix SMB/CIFS implementation.
   SMB parameters and setup
   Copyright (C) Andrew Tridgell 1992-1998
   Modified by Jeremy Allison 1995.
   Copyright (C) Jeremy Allison 1995-2000.
   Copyright (C) Luke Kennethc Casson Leighton 1996-2000.
   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "includes.h"
#include "system/time.h"
#include "../libcli/auth/msrpc_parse.h"
#include "../lib/crypto/crypto.h"
#include "../libcli/auth/libcli_auth.h"
#include "../librpc/gen_ndr/ndr_ntlmssp.h"
#include "lib/util/bytearray.h"

#include "lib/crypto/gnutls_helpers.h"
#include <gnutls/gnutls.h>
#include <gnutls/crypto.h>

int SMBencrypt_hash(const uint8_t lm_hash[16], const uint8_t *c8, uint8_t p24[24])
{
        uint8_t p21[21];
        int rc;

        memset(p21,'\0',21);
        memcpy(p21, lm_hash, 16);

        rc = SMBOWFencrypt(p21, c8, p24);

#ifdef DEBUG_PASSWORD
        DEBUG(100,("SMBencrypt_hash: lm#, challenge, response\n"));
        dump_data(100, p21, 16);
        dump_data(100, c8, 8);
        dump_data(100, p24, 24);
#endif

        return rc;
}

/*
   This implements the X/Open SMB password encryption
   It takes a password ('unix' string), a 8 byte "crypt key"
   and puts 24 bytes of encrypted password into p24

   Returns False if password must have been truncated to create LM hash
*/

bool SMBencrypt(const char *passwd, const uint8_t *c8, uint8_t p24[24])
{
        bool ret;
        uint8_t lm_hash[16];
        int rc;

        ret = E_deshash(passwd, lm_hash);
        rc = SMBencrypt_hash(lm_hash, c8, p24);
        if (rc != 0) {
                ret = false;
        }
        return ret;
}

/**
 * Creates the MD4 Hash of the users password in NT UNICODE.
 * @param passwd password in 'unix' charset.
 * @param p16 return password hashed with md4, caller allocated 16 byte buffer
 */

bool E_md4hash(const char *passwd, uint8_t p16[16])
{
        size_t len;
        smb_ucs2_t *wpwd;
        bool ret;

        ret = push_ucs2_talloc(NULL, &wpwd, passwd, &len);
        if (!ret || len < 2) {
                /* We don't want to return fixed data, as most callers
                 * don't check */
                mdfour(p16, (const uint8_t *)passwd, strlen(passwd));
                return false;
        }

        len -= 2;
        mdfour(p16, (const uint8_t *)wpwd, len);

        talloc_free(wpwd);
        return true;
}

/**
 * Creates the DES forward-only Hash of the users password in DOS ASCII charset
 * @param passwd password in 'unix' charset.
 * @param p16 return password hashed with DES, caller allocated 16 byte buffer
 * @return false if password was > 14 characters, and therefore may be incorrect, otherwise true
 * @note p16 is filled in regardless
 */

bool E_deshash(const char *passwd, uint8_t p16[16])
{
        bool ret;
        int rc;
        uint8_t dospwd[14];
        TALLOC_CTX *frame = talloc_stackframe();

        size_t converted_size;

        char *tmpbuf;

        ZERO_STRUCT(dospwd);

        tmpbuf = strupper_talloc(frame, passwd);
        if (tmpbuf == NULL) {
                /* Too many callers don't check this result, we need to fill in the buffer with something */
                strlcpy((char *)dospwd, passwd ? passwd : "", sizeof(dospwd));
                E_P16(dospwd, p16);
                talloc_free(frame);
                return false;
        }

        ZERO_STRUCT(dospwd);

        ret = convert_string_error(CH_UNIX, CH_DOS, tmpbuf, strlen(tmpbuf), dospwd, sizeof(dospwd), &converted_size);
        talloc_free(frame);

        /* Only the first 14 chars are considered, password need not
         * be null terminated.  We do this in the error and success
         * case to avoid returning a fixed 'password' buffer, but
         * callers should not use it when E_deshash returns false */

        rc = E_P16((const uint8_t *)dospwd, p16);
        if (rc != 0) {
                ret = false;
        }

        ZERO_STRUCT(dospwd);

        return ret;
}

/**
 * Creates the MD4 and DES (LM) Hash of the users password.
 * MD4 is of the NT Unicode, DES is of the DOS UPPERCASE password.
 * @param passwd password in 'unix' charset.
 * @param nt_p16 return password hashed with md4, caller allocated 16 byte buffer
 * @param p16 return password hashed with des, caller allocated 16 byte buffer
 */

/* Does both the NT and LM owfs of a user's password */
void nt_lm_owf_gen(const char *pwd, uint8_t nt_p16[16], uint8_t p16[16])
{
        /* Calculate the MD4 hash (NT compatible) of the password */
        memset(nt_p16, '\0', 16);
        E_md4hash(pwd, nt_p16);

#ifdef DEBUG_PASSWORD
        DEBUG(100,("nt_lm_owf_gen: pwd, nt#\n"));
        dump_data(120, (const uint8_t *)pwd, strlen(pwd));
        dump_data(100, nt_p16, 16);
#endif

        E_deshash(pwd, (uint8_t *)p16);

#ifdef DEBUG_PASSWORD
        DEBUG(100,("nt_lm_owf_gen: pwd, lm#\n"));
        dump_data(120, (const uint8_t *)pwd, strlen(pwd));
        dump_data(100, p16, 16);
#endif
}

/* Does both the NTLMv2 owfs of a user's password */
bool ntv2_owf_gen(const uint8_t owf[16],
                  const char *user_in, const char *domain_in,
                  uint8_t kr_buf[16])
{
        smb_ucs2_t *user;
        smb_ucs2_t *domain;
        size_t user_byte_len;
        size_t domain_byte_len;
        gnutls_hmac_hd_t hmac_hnd = NULL;
        int rc;
        bool ok = false;
        TALLOC_CTX *mem_ctx = talloc_init("ntv2_owf_gen for %s\\%s", domain_in, user_in);

        if (!mem_ctx) {
                return false;
        }

        if (!user_in) {
                user_in = "";
        }

        if (!domain_in) {
                domain_in = "";
        }

        user_in = strupper_talloc(mem_ctx, user_in);
        if (user_in == NULL) {
                talloc_free(mem_ctx);
                return false;
        }

        ok = push_ucs2_talloc(mem_ctx, &user, user_in, &user_byte_len );
        if (!ok) {
                DEBUG(0, ("push_uss2_talloc() for user failed)\n"));
                talloc_free(mem_ctx);
                return false;
        }

        ok = push_ucs2_talloc(mem_ctx, &domain, domain_in, &domain_byte_len);
        if (!ok) {
                DEBUG(0, ("push_ucs2_talloc() for domain failed\n"));
                talloc_free(mem_ctx);
                return false;
        }

        SMB_ASSERT(user_byte_len >= 2);
        SMB_ASSERT(domain_byte_len >= 2);

        /* We don't want null termination */
        user_byte_len = user_byte_len - 2;
        domain_byte_len = domain_byte_len - 2;

        rc = gnutls_hmac_init(&hmac_hnd,
                              GNUTLS_MAC_MD5,
                              owf,
                              16);
        if (rc < 0) {
                ok = false;
                goto out;
        }

        rc = gnutls_hmac(hmac_hnd, user, user_byte_len);
        if (rc < 0) {
                gnutls_hmac_deinit(hmac_hnd, NULL);
                ok = false;
                goto out;
        }
        rc = gnutls_hmac(hmac_hnd, domain, domain_byte_len);
        if (rc < 0) {
                gnutls_hmac_deinit(hmac_hnd, NULL);
                ok = false;
                goto out;
        }

        gnutls_hmac_deinit(hmac_hnd, kr_buf);

#ifdef DEBUG_PASSWORD
        DEBUG(100, ("ntv2_owf_gen: user, domain, owfkey, kr\n"));
        dump_data(100, (uint8_t *)user, user_byte_len);
        dump_data(100, (uint8_t *)domain, domain_byte_len);
        dump_data(100, owf, 16);
        dump_data(100, kr_buf, 16);
#endif

        ok = true;
out:
        talloc_free(mem_ctx);
        return ok;
}

/* Does the des encryption from the NT or LM MD4 hash. */
int SMBOWFencrypt(const uint8_t passwd[16], const uint8_t *c8, uint8_t p24[24])
{
        uint8_t p21[21];

        ZERO_STRUCT(p21);

        memcpy(p21, passwd, 16);
        return E_P24(p21, c8, p24);
}

/* Does the des encryption. */

int SMBNTencrypt_hash(const uint8_t nt_hash[16], const uint8_t *c8, uint8_t *p24)
{
        uint8_t p21[21];
        int rc;

        memset(p21,'\0',21);
        memcpy(p21, nt_hash, 16);
        rc = SMBOWFencrypt(p21, c8, p24);

#ifdef DEBUG_PASSWORD
        DEBUG(100,("SMBNTencrypt: nt#, challenge, response\n"));
        dump_data(100, p21, 16);
        dump_data(100, c8, 8);
        dump_data(100, p24, 24);
#endif

        return rc;
}

/* Does the NT MD4 hash then des encryption. Plaintext version of the above. */

int SMBNTencrypt(const char *passwd, const uint8_t *c8, uint8_t *p24)
{
        uint8_t nt_hash[16];
        E_md4hash(passwd, nt_hash);
        return SMBNTencrypt_hash(nt_hash, c8, p24);
}


/* Does the md5 encryption from the Key Response for NTLMv2. */
NTSTATUS SMBOWFencrypt_ntv2(const uint8_t kr[16],
                            const DATA_BLOB *srv_chal,
                            const DATA_BLOB *smbcli_chal,
                            uint8_t resp_buf[16])
{
        gnutls_hmac_hd_t hmac_hnd = NULL;
        NTSTATUS status;
        int rc;

        rc = gnutls_hmac_init(&hmac_hnd,
                              GNUTLS_MAC_MD5,
                              kr,
                              16);
        if (rc < 0) {
                return gnutls_error_to_ntstatus(rc, NT_STATUS_HMAC_NOT_SUPPORTED);
        }

        rc = gnutls_hmac(hmac_hnd, srv_chal->data, srv_chal->length);
        if (rc < 0) {
                status = gnutls_error_to_ntstatus(rc, NT_STATUS_HMAC_NOT_SUPPORTED);
                goto out;
        }
        rc = gnutls_hmac(hmac_hnd, smbcli_chal->data, smbcli_chal->length);
        if (rc < 0) {
                status = gnutls_error_to_ntstatus(rc, NT_STATUS_HMAC_NOT_SUPPORTED);
                goto out;
        }


        status = NT_STATUS_OK;
out:
        gnutls_hmac_deinit(hmac_hnd, resp_buf);
#ifdef DEBUG_PASSWORD
        DEBUG(100, ("SMBOWFencrypt_ntv2: srv_chal, smbcli_chal, resp_buf: %s\n",
                    nt_errstr(status)));
        dump_data(100, srv_chal->data, srv_chal->length);
        dump_data(100, smbcli_chal->data, smbcli_chal->length);
        dump_data(100, resp_buf, 16);
#endif
        return status;
}

NTSTATUS SMBsesskeygen_ntv2(const uint8_t kr[16],
                            const uint8_t *nt_resp,
                            uint8_t sess_key[16])
{
        int rc;

        /* a very nice, 128 bit, variable session key */
        rc = gnutls_hmac_fast(GNUTLS_MAC_MD5,
                              kr,
                              16,
                              nt_resp,
                              16,
                              sess_key);
        if (rc != 0) {
                return gnutls_error_to_ntstatus(rc, NT_STATUS_HMAC_NOT_SUPPORTED);
        }

#ifdef DEBUG_PASSWORD
        DEBUG(100, ("SMBsesskeygen_ntv2:\n"));
        dump_data(100, sess_key, 16);
#endif

        return NT_STATUS_OK;
}

void SMBsesskeygen_ntv1(const uint8_t kr[16], uint8_t sess_key[16])
{
        /* yes, this session key does not change - yes, this
           is a problem - but it is 128 bits */

        mdfour((uint8_t *)sess_key, kr, 16);

#ifdef DEBUG_PASSWORD
        DEBUG(100, ("SMBsesskeygen_ntv1:\n"));
        dump_data(100, sess_key, 16);
#endif
}

NTSTATUS SMBsesskeygen_lm_sess_key(const uint8_t lm_hash[16],
                               const uint8_t lm_resp[24], /* only uses 8 */
                               uint8_t sess_key[16])
{
        /* Calculate the LM session key (effective length 40 bits,
           but changes with each session) */
        uint8_t p24[24];
        uint8_t partial_lm_hash[14];
        int rc;

        memcpy(partial_lm_hash, lm_hash, 8);
        memset(partial_lm_hash + 8, 0xbd, 6);

        rc = des_crypt56_gnutls(p24, lm_resp, partial_lm_hash, SAMBA_GNUTLS_ENCRYPT);
        if (rc < 0) {
                return gnutls_error_to_ntstatus(rc, NT_STATUS_ACCESS_DISABLED_BY_POLICY_OTHER);
        }
        rc = des_crypt56_gnutls(p24+8, lm_resp, partial_lm_hash + 7, SAMBA_GNUTLS_ENCRYPT);
        if (rc < 0) {
                return gnutls_error_to_ntstatus(rc, NT_STATUS_ACCESS_DISABLED_BY_POLICY_OTHER);
        }

        memcpy(sess_key, p24, 16);

#ifdef DEBUG_PASSWORD
        DEBUG(100, ("SMBsesskeygen_lm_sess_key: \n"));
        dump_data(100, sess_key, 16);
#endif

        return NT_STATUS_OK;
}

DATA_BLOB NTLMv2_generate_names_blob(TALLOC_CTX *mem_ctx,
                                     const char *hostname,
                                     const char *domain)
{
        DATA_BLOB names_blob = data_blob_talloc(mem_ctx, NULL, 0);

        /* Deliberately ignore return here.. */
        if (hostname != NULL) {
                (void)msrpc_gen(mem_ctx, &names_blob,
                          "aaa",
                          MsvAvNbDomainName, domain,
                          MsvAvNbComputerName, hostname,
                          MsvAvEOL, "");
        } else {
                (void)msrpc_gen(mem_ctx, &names_blob,
                          "aa",
                          MsvAvNbDomainName, domain,
                          MsvAvEOL, "");
        }
        return names_blob;
}

static DATA_BLOB NTLMv2_generate_client_data(TALLOC_CTX *mem_ctx,
                                             NTTIME nttime,
                                             const DATA_BLOB *names_blob)
{
        uint8_t client_chal[8];
        DATA_BLOB response = data_blob(NULL, 0);
        uint8_t long_date[8];

        generate_random_buffer(client_chal, sizeof(client_chal));

        push_nttime(long_date, 0, nttime);

        /* See http://www.ubiqx.org/cifs/SMB.html#SMB.8.5 */

        /* Deliberately ignore return here.. */
        (void)msrpc_gen(mem_ctx, &response, "ddbbdb",
                  0x00000101,     /* Header  */
                  0,              /* 'Reserved'  */
                  long_date, 8,   /* Timestamp */
                  client_chal, 8, /* client challenge */
                  0,              /* Unknown */
                  names_blob->data, names_blob->length);        /* End of name list */

        return response;
}

static DATA_BLOB NTLMv2_generate_response(TALLOC_CTX *out_mem_ctx,
                                          const uint8_t ntlm_v2_hash[16],
                                          const DATA_BLOB *server_chal,
                                          NTTIME nttime,
                                          const DATA_BLOB *names_blob)
{
        uint8_t ntlmv2_response[16];
        DATA_BLOB ntlmv2_client_data;
        DATA_BLOB final_response;
        NTSTATUS status;

        TALLOC_CTX *mem_ctx = talloc_named(out_mem_ctx, 0,
                                           "NTLMv2_generate_response internal context");

        if (!mem_ctx) {
                return data_blob(NULL, 0);
        }

        /* NTLMv2 */
        /* generate some data to pass into the response function - including
           the hostname and domain name of the server */
        ntlmv2_client_data = NTLMv2_generate_client_data(mem_ctx, nttime, names_blob);

        /* Given that data, and the challenge from the server, generate a response */
        status = SMBOWFencrypt_ntv2(ntlm_v2_hash,
                                    server_chal,
                                    &ntlmv2_client_data,
                                    ntlmv2_response);
        if (!NT_STATUS_IS_OK(status)) {
                talloc_free(mem_ctx);
                return data_blob(NULL, 0);
        }

        final_response = data_blob_talloc(out_mem_ctx, NULL, sizeof(ntlmv2_response) + ntlmv2_client_data.length);

        memcpy(final_response.data, ntlmv2_response, sizeof(ntlmv2_response));

        memcpy(final_response.data+sizeof(ntlmv2_response),
               ntlmv2_client_data.data, ntlmv2_client_data.length);

        talloc_free(mem_ctx);

        return final_response;
}

static DATA_BLOB LMv2_generate_response(TALLOC_CTX *mem_ctx,
                                        const uint8_t ntlm_v2_hash[16],
                                        const DATA_BLOB *server_chal)
{
        uint8_t lmv2_response[16];
        DATA_BLOB lmv2_client_data = data_blob_talloc(mem_ctx, NULL, 8);
        DATA_BLOB final_response = data_blob_talloc(mem_ctx, NULL,24);
        NTSTATUS status;

        /* LMv2 */
        /* client-supplied random data */
        generate_random_buffer(lmv2_client_data.data, lmv2_client_data.length);

        /* Given that data, and the challenge from the server, generate a response */
        status = SMBOWFencrypt_ntv2(ntlm_v2_hash,
                                    server_chal,
                                    &lmv2_client_data,
                                    lmv2_response);
        if (!NT_STATUS_IS_OK(status)) {
                data_blob_free(&lmv2_client_data);
                return data_blob(NULL, 0);
        }
        memcpy(final_response.data, lmv2_response, sizeof(lmv2_response));

        /* after the first 16 bytes is the random data we generated above,
           so the server can verify us with it */
        memcpy(final_response.data+sizeof(lmv2_response),
               lmv2_client_data.data, lmv2_client_data.length);

        data_blob_free(&lmv2_client_data);

        return final_response;
}

bool SMBNTLMv2encrypt_hash(TALLOC_CTX *mem_ctx,
                           const char *user, const char *domain, const uint8_t nt_hash[16],
                           const DATA_BLOB *server_chal,
                           const NTTIME *server_timestamp,
                           const DATA_BLOB *names_blob,
                           DATA_BLOB *lm_response, DATA_BLOB *nt_response,
                           DATA_BLOB *lm_session_key, DATA_BLOB *user_session_key)
{
        uint8_t ntlm_v2_hash[16];
        NTSTATUS status;

        /* We don't use the NT# directly.  Instead we use it mashed up with
           the username and domain.
           This prevents username swapping during the auth exchange
        */
        if (!ntv2_owf_gen(nt_hash, user, domain, ntlm_v2_hash)) {
                return false;
        }

        if (nt_response) {
                const NTTIME *nttime = server_timestamp;
                NTTIME _now = 0;

                if (nttime == NULL) {
                        struct timeval tv_now = timeval_current();
                        _now = timeval_to_nttime(&tv_now);
                        nttime = &_now;
                }

                *nt_response = NTLMv2_generate_response(mem_ctx,
                                                        ntlm_v2_hash,
                                                        server_chal,
                                                        *nttime,
                                                        names_blob);
                if (user_session_key) {
                        *user_session_key = data_blob_talloc(mem_ctx, NULL, 16);

                        /* The NTLMv2 calculations also provide a session key, for signing etc later */
                        /* use only the first 16 bytes of nt_response for session key */
                        status = SMBsesskeygen_ntv2(ntlm_v2_hash,
                                                    nt_response->data,
                                                    user_session_key->data);
                        if (!NT_STATUS_IS_OK(status)) {
                                return false;
                        }
                }
        }

        /* LMv2 */

        if (lm_response) {
                if (server_timestamp != NULL) {
                        *lm_response = data_blob_talloc_zero(mem_ctx, 24);
                } else {
                        *lm_response = LMv2_generate_response(mem_ctx,
                                                              ntlm_v2_hash,
                                                              server_chal);
                }
                if (lm_session_key) {
                        *lm_session_key = data_blob_talloc(mem_ctx, NULL, 16);

                        /* The NTLMv2 calculations also provide a session key, for signing etc later */
                        /* use only the first 16 bytes of lm_response for session key */
                        status = SMBsesskeygen_ntv2(ntlm_v2_hash,
                                                    lm_response->data,
                                                    lm_session_key->data);
                        if (!NT_STATUS_IS_OK(status)) {
                                return false;
                        }
                }
        }

        return true;
}

bool SMBNTLMv2encrypt(TALLOC_CTX *mem_ctx,
                      const char *user, const char *domain,
                      const char *password,
                      const DATA_BLOB *server_chal,
                      const DATA_BLOB *names_blob,
                      DATA_BLOB *lm_response, DATA_BLOB *nt_response,
                      DATA_BLOB *lm_session_key, DATA_BLOB *user_session_key)
{
        uint8_t nt_hash[16];
        E_md4hash(password, nt_hash);

        return SMBNTLMv2encrypt_hash(mem_ctx,
                                     user, domain, nt_hash,
                                     server_chal, NULL, names_blob,
                                     lm_response, nt_response, lm_session_key, user_session_key);
}

NTSTATUS NTLMv2_RESPONSE_verify_netlogon_creds(const char *account_name,
                        const char *account_domain,
                        const DATA_BLOB response,
                        const struct netlogon_creds_CredentialState *creds,
                        const char *workgroup)
{
        TALLOC_CTX *frame = NULL;
        /* RespType + HiRespType */
        static const char *magic = "\x01\x01";
        int cmp;
        struct NTLMv2_RESPONSE v2_resp;
        enum ndr_err_code err;
        const struct AV_PAIR *av_nb_cn = NULL;
        const struct AV_PAIR *av_nb_dn = NULL;

        if (response.length < 48) {
                /*
                 * NTLMv2_RESPONSE has at least 48 bytes.
                 */
                return NT_STATUS_OK;
        }

        cmp = memcmp(response.data + 16, magic, 2);
        if (cmp != 0) {
                /*
                 * It doesn't look like a valid NTLMv2_RESPONSE
                 */
                return NT_STATUS_OK;
        }

        if (response.length == 95) {
                /*
                 * ndr_pull_NTLMv2_RESPONSE() fails on this strange blob,
                 * because the AvPairs content is not valid
                 * as AvLen of the first pair is 33032 (0x8108).
                 *
                 * I saw a single machine sending the following 3 times
                 * in a row, but I'm not sure if everything is static.
                 *
                 * Note this is NTLMv2_CLIENT_CHALLENGE only, not
                 * the full NTLMv2_RESPONSE (which has Response of 16 bytes
                 * before the NTLMv2_CLIENT_CHALLENGE).
                 *
                 * Note this code only prevents
                 * ndr_pull_error(Buffer Size Error): Pull bytes 39016
                 * debug message for a known case, the actual
                 * bug is also handled below in a generic way to
                 * map NT_STATUS_BUFFER_TOO_SMALL to NT_STATUS_OK.
                 *
                 * See https://bugzilla.samba.org/show_bug.cgi?id=14932
                 */
                static const char *netapp_magic =
                        "\x01\x01\x00\x00\x00\x00\x00\x00"
                        "\x3f\x3f\x3f\x3f\x3f\x3f\x3f\x3f"
                        "\xb8\x82\x3a\xf1\xb3\xdd\x08\x15"
                        "\x00\x00\x00\x00\x11\xa2\x08\x81"
                        "\x50\x38\x22\x78\x2b\x94\x47\xfe"
                        "\x54\x94\x7b\xff\x17\x27\x5a\xb4"
                        "\xf4\x18\xba\xdc\x2c\x38\xfd\x5b"
                        "\xfb\x0e\xc1\x85\x1e\xcc\x92\xbb"
                        "\x9b\xb1\xc4\xd5\x53\x14\xff\x8c"
                        "\x76\x49\xf5\x45\x90\x19\xa2";
                /*
                 * First we check the initial bytes
                 * and the 0x3F timestamp.
                 */
                cmp = memcmp(response.data + 16,
                             netapp_magic,
                             16);
                if (cmp == 0) {
                        /*
                         * Then check everything after the
                         * client challenge
                         */
                        cmp = memcmp(response.data + 40,
                                     netapp_magic + 24,
                                     response.length - 40);
                        if (cmp == 0) {
                                DBG_DEBUG("Invalid NETAPP NTLMv2_RESPONSE "
                                          "for user[%s\\%s] against "
                                          "SEC_CHAN(%u)[%s/%s] "
                                          "in workgroup[%s]\n",
                                          account_domain,
                                          account_name,
                                          creds->secure_channel_type,
                                          creds->computer_name,
                                          creds->account_name,
                                          workgroup);
                                return NT_STATUS_OK;
                        }
                }
        }

        frame = talloc_stackframe();

        err = ndr_pull_struct_blob(&response, frame, &v2_resp,
                (ndr_pull_flags_fn_t)ndr_pull_NTLMv2_RESPONSE);
        if (!NDR_ERR_CODE_IS_SUCCESS(err)) {
                NTSTATUS status;
                status = ndr_map_error2ntstatus(err);
                if (NT_STATUS_EQUAL(status, NT_STATUS_BUFFER_TOO_SMALL)) {
                        /*
                         * We are supposed to ignore invalid buffers,
                         * see https://bugzilla.samba.org/show_bug.cgi?id=14932
                         */
                        status = NT_STATUS_OK;
                }
                DEBUG(2,("%s: Failed to parse NTLMv2_RESPONSE length=%u "
                        "for user[%s\\%s] against SEC_CHAN(%u)[%s/%s] "
                        "in workgroup[%s] - %s %s %s\n",
                        __func__,
                        (unsigned)response.length,
                        account_domain,
                        account_name,
                        creds->secure_channel_type,
                        creds->computer_name,
                        creds->account_name,
                        workgroup,
                        ndr_map_error2string(err),
                        NT_STATUS_IS_OK(status) ? "(ignoring) =>" : "=>",
                        nt_errstr(status)));
                dump_data(2, response.data, response.length);
                TALLOC_FREE(frame);
                return status;
        }

        if (DEBUGLVL(10)) {
                NDR_PRINT_DEBUG(NTLMv2_RESPONSE, &v2_resp);
        }

        /*
         * Make sure the netbios computer name in the
         * NTLMv2_RESPONSE matches the computer name
         * in the secure channel credentials for workstation
         * trusts.
         *
         * And the netbios domain name matches our
         * workgroup.
         *
         * This prevents workstations from requesting
         * the session key of NTLMSSP sessions of clients
         * to other hosts.
         */
        if (creds->secure_channel_type == SEC_CHAN_WKSTA) {
                av_nb_cn = ndr_ntlmssp_find_av(&v2_resp.Challenge.AvPairs,
                                               MsvAvNbComputerName);
                av_nb_dn = ndr_ntlmssp_find_av(&v2_resp.Challenge.AvPairs,
                                               MsvAvNbDomainName);
        }

        if (av_nb_cn != NULL) {
                const char *v = NULL;
                char *a = NULL;
                size_t len;

                v = av_nb_cn->Value.AvNbComputerName;

                a = talloc_strdup(frame, creds->account_name);
                if (a == NULL) {
                        TALLOC_FREE(frame);
                        return NT_STATUS_NO_MEMORY;
                }
                len = strlen(a);
                if (len > 0 && a[len - 1] == '$') {
                        a[len - 1] = '\0';
                }

                cmp = strcasecmp_m(a, v);
                if (cmp != 0) {
                        DEBUG(2,("%s: NTLMv2_RESPONSE with "
                                 "NbComputerName[%s] rejected "
                                 "for user[%s\\%s] "
                                 "against SEC_CHAN_WKSTA[%s/%s] "
                                 "in workgroup[%s]\n",
                                 __func__, v,
                                 account_domain,
                                 account_name,
                                 creds->computer_name,
                                 creds->account_name,
                                 workgroup));
                        TALLOC_FREE(frame);
                        return NT_STATUS_LOGON_FAILURE;
                }
        }
        if (av_nb_dn != NULL) {
                const char *v = NULL;

                v = av_nb_dn->Value.AvNbDomainName;

                cmp = strcasecmp_m(workgroup, v);
                if (cmp != 0) {
                        DEBUG(2,("%s: NTLMv2_RESPONSE with "
                                 "NbDomainName[%s] rejected "
                                 "for user[%s\\%s] "
                                 "against SEC_CHAN_WKSTA[%s/%s] "
                                 "in workgroup[%s]\n",
                                 __func__, v,
                                 account_domain,
                                 account_name,
                                 creds->computer_name,
                                 creds->account_name,
                                 workgroup));
                        TALLOC_FREE(frame);
                        return NT_STATUS_LOGON_FAILURE;
                }
        }

        TALLOC_FREE(frame);
        return NT_STATUS_OK;
}

enum encode_order {
        ENCODE_ORDER_PASSWORD_FIRST,
        ENCODE_ORDER_PASSWORD_LAST,
};

#define PASSWORD_BUFFER_LEN 512

static ssize_t _encode_pwd_buffer_from_str(uint8_t buf[PASSWORD_BUFFER_LEN],
                                           const char *password,
                                           int string_flags,
                                           enum encode_order order)
{
        ssize_t new_pw_len;
        size_t pw_pos = 0;
        size_t random_pos = 0;
        size_t random_len = 0;

        /* The incoming buffer can be any alignment. */
        string_flags |= STR_NOALIGN;

        new_pw_len = push_string(buf,
                                 password,
                                 PASSWORD_BUFFER_LEN,
                                 string_flags);
        if (new_pw_len < 0) {
                BURN_DATA_SIZE(buf, PASSWORD_BUFFER_LEN);
                return -1;
        }

        if (new_pw_len == PASSWORD_BUFFER_LEN) {
                return new_pw_len;
        }

        switch (order) {
        case ENCODE_ORDER_PASSWORD_FIRST:
                pw_pos = 0;
                random_pos = new_pw_len;
                random_len = PASSWORD_BUFFER_LEN - random_pos;
                break;
        case ENCODE_ORDER_PASSWORD_LAST:
                pw_pos = PASSWORD_BUFFER_LEN - new_pw_len;
                random_pos = 0;
                random_len = pw_pos;
                memmove(buf + pw_pos, buf, new_pw_len);
                break;
        }

        generate_random_buffer(buf + random_pos, random_len);

        return new_pw_len;
}

/***********************************************************
 encode a password buffer with a unicode password.  The buffer
 is filled with random data to make it harder to attack.
************************************************************/
bool encode_pw_buffer(uint8_t buffer[516], const char *password, int string_flags)
{
        ssize_t pw_len;

        pw_len = _encode_pwd_buffer_from_str(buffer,
                                             password,
                                             string_flags,
                                             ENCODE_ORDER_PASSWORD_LAST);
        if (pw_len < 0 || pw_len > PASSWORD_BUFFER_LEN) {
                return false;
        }

        PUSH_LE_U32(buffer, PASSWORD_BUFFER_LEN, pw_len);

        return true;
}


/***********************************************************
 decode a password buffer
 *new_pw_len is the length in bytes of the possibly mulitbyte
 returned password including termination.
************************************************************/

bool decode_pw_buffer(TALLOC_CTX *ctx,
                      uint8_t in_buffer[516],
                      char **pp_new_pwrd,
                      size_t *new_pw_len,
                      charset_t string_charset)
{
        DATA_BLOB new_password;
        int byte_len=0;
        bool ok;

        *pp_new_pwrd = NULL;
        *new_pw_len = 0;

        ok = extract_pw_from_buffer(ctx, in_buffer, &new_password);
        if (!ok) {
                return false;
        }

        /*
          Warning !!! : This function is called from some rpc call.
          The password IN the buffer may be a UNICODE string.
          The password IN new_pwrd is an ASCII string
          If you reuse that code somewhere else check first.
        */

        /* decode into the return buffer. */
        ok = convert_string_talloc(ctx,
                                   string_charset,
                                   CH_UNIX,
                                   new_password.data,
                                   new_password.length,
                                   pp_new_pwrd,
                                   new_pw_len);
        data_blob_free(&new_password);
        if (!ok) {
                DBG_ERR("Failed to convert incoming password\n");
                return false;
        }
        talloc_keep_secret(*pp_new_pwrd);

#ifdef DEBUG_PASSWORD
        DEBUG(100,("decode_pw_buffer: new_pwrd: "));
        dump_data(100, (uint8_t *)*pp_new_pwrd, *new_pw_len);
        DEBUG(100,("multibyte len:%lu\n", (unsigned long int)*new_pw_len));
        DEBUG(100,("original char len:%d\n", byte_len/2));
#endif

        return true;
}

#define MAX_PASSWORD_LEN 256

/*
 * [MS-SAMR] 2.2.6.32 This creates the buffer to be sent. It is of type
 * SAMPR_USER_PASSWORD_AES.
 */
bool encode_pwd_buffer514_from_str(uint8_t buffer[514],
                                   const char *password,
                                   uint32_t string_flags)
{
        ssize_t pw_len;

        pw_len = _encode_pwd_buffer_from_str(buffer + 2,
                                             password,
                                             string_flags,
                                             ENCODE_ORDER_PASSWORD_FIRST);
        if (pw_len < 0) {
                return false;
        }

        PUSH_LE_U16(buffer, 0, pw_len);

        return true;
}

bool extract_pwd_blob_from_buffer514(TALLOC_CTX *mem_ctx,
                                     const uint8_t in_buffer[514],
                                     DATA_BLOB *new_password)
{
#ifdef DEBUG_PASSWORD
        DEBUG(100, ("in_buffer: "));
        dump_data(100, in_buffer, 514);
#endif

        new_password->length = PULL_LE_U16(in_buffer, 0);
        if (new_password->length == 0 || new_password->length > 512) {
                return false;
        }

        new_password->data =
                talloc_memdup(mem_ctx, in_buffer + 2, new_password->length);
        if (new_password->data == NULL) {
                return false;
        }
        talloc_keep_secret(new_password->data);

#ifdef DEBUG_PASSWORD
        DEBUG(100, ("new_pwd_len: %zu\n", new_password->length));
        DEBUG(100, ("new_pwd: "));
        dump_data(100, new_password->data, new_password->length);
#endif

        return true;
}

bool decode_pwd_string_from_buffer514(TALLOC_CTX *mem_ctx,
                                      const uint8_t in_buffer[514],
                                      charset_t string_charset,
                                      DATA_BLOB *decoded_password)
{
        DATA_BLOB new_password = {
                .length = 0,
        };
        bool ok;

        ok = extract_pwd_blob_from_buffer514(mem_ctx, in_buffer, &new_password);
        if (!ok) {
                return false;
        }

        ok = convert_string_talloc(mem_ctx,
                                   string_charset,
                                   CH_UNIX,
                                   new_password.data,
                                   new_password.length,
                                   &decoded_password->data,
                                   &decoded_password->length);
        data_blob_free(&new_password);
        if (!ok) {
                return false;
        }
        talloc_keep_secret(decoded_password->data);

        return true;
}

/***********************************************************
 Encode an arc4 password change buffer.
************************************************************/
NTSTATUS encode_rc4_passwd_buffer(const char *passwd,
                                  const DATA_BLOB *session_key,
                                  struct samr_CryptPasswordEx *out_crypt_pwd)
{
        uint8_t _confounder[16] = {0};
        DATA_BLOB confounder = data_blob_const(_confounder, 16);
        DATA_BLOB pw_data = data_blob_const(out_crypt_pwd->data, 516);
        bool ok;
        int rc;

        ok = encode_pw_buffer(pw_data.data, passwd, STR_UNICODE);
        if (!ok) {
                return NT_STATUS_INVALID_PARAMETER;
        }

        generate_random_buffer(confounder.data, confounder.length);

        rc = samba_gnutls_arcfour_confounded_md5(&confounder,
                                                 session_key,
                                                 &pw_data,
                                                 SAMBA_GNUTLS_ENCRYPT);
        if (rc < 0) {
                ZERO_ARRAY(_confounder);
                data_blob_clear(&pw_data);
                return gnutls_error_to_ntstatus(rc, NT_STATUS_ACCESS_DISABLED_BY_POLICY_OTHER);
        }

        /*
         * The packet format is the 516 byte RC4 encrypted
         * password followed by the 16 byte confounder
         * The confounder is a salt to prevent pre-computed hash attacks on the
         * database.
         */
        memcpy(&out_crypt_pwd->data[516], confounder.data, confounder.length);
        ZERO_ARRAY(_confounder);

        return NT_STATUS_OK;
}

/***********************************************************
 Decode an arc4 encrypted password change buffer.
************************************************************/

NTSTATUS decode_rc4_passwd_buffer(const DATA_BLOB *psession_key,
                                  struct samr_CryptPasswordEx *inout_crypt_pwd)
{
        /* Confounder is last 16 bytes. */
        DATA_BLOB confounder = data_blob_const(&inout_crypt_pwd->data[516], 16);
        DATA_BLOB pw_data = data_blob_const(&inout_crypt_pwd->data, 516);
        int rc;

        rc = samba_gnutls_arcfour_confounded_md5(&confounder,
                                                 psession_key,
                                                 &pw_data,
                                                 SAMBA_GNUTLS_DECRYPT);
        if (rc < 0) {
                return gnutls_error_to_ntstatus(rc, NT_STATUS_ACCESS_DISABLED_BY_POLICY_OTHER);
        }

        return NT_STATUS_OK;
}

/***********************************************************
 encode a password buffer with an already unicode password.  The
 rest of the buffer is filled with random data to make it harder to attack.
************************************************************/

static bool create_pw_buffer_from_blob(uint8_t buffer[512],
                                       const DATA_BLOB *in_password,
                                       enum encode_order order)
{
        size_t pwd_pos = 0;
        size_t random_pos = 0;
        size_t random_len = 0;

        if (in_password->length > 512) {
                return false;
        }

        switch (order) {
        case ENCODE_ORDER_PASSWORD_FIRST:
                pwd_pos = 0;
                random_pos = in_password->length;
                break;
        case ENCODE_ORDER_PASSWORD_LAST:
                pwd_pos = PASSWORD_BUFFER_LEN - in_password->length;
                random_pos = 0;
                break;
        }
        random_len = PASSWORD_BUFFER_LEN - in_password->length;

        memcpy(buffer + pwd_pos, in_password->data, in_password->length);
        generate_random_buffer(buffer + random_pos, random_len);

        return true;
}

bool set_pw_in_buffer(uint8_t buffer[516], const DATA_BLOB *password)
{
        bool ok;

        ok = create_pw_buffer_from_blob(buffer,
                                        password,
                                        ENCODE_ORDER_PASSWORD_LAST);
        if (!ok) {
                return false;
        }

        /*
         * The length of the new password is in the last 4 bytes of
         * the data buffer.
         */
        PUSH_LE_U32(buffer, PASSWORD_BUFFER_LEN, password->length);

        return true;
}

/***********************************************************
 decode a password buffer
 *new_pw_size is the length in bytes of the extracted unicode password
************************************************************/
bool extract_pw_from_buffer(TALLOC_CTX *mem_ctx,
                            uint8_t in_buffer[516], DATA_BLOB *new_pass)
{
        int byte_len=0;

        /* The length of the new password is in the last 4 bytes of the data buffer. */

        byte_len = IVAL(in_buffer, 512);

#ifdef DEBUG_PASSWORD
        dump_data(100, in_buffer, 516);
#endif

        /* Password cannot be longer than the size of the password buffer */
        if ( (byte_len < 0) || (byte_len > 512)) {
                return false;
        }

        *new_pass = data_blob_talloc(mem_ctx, &in_buffer[512 - byte_len], byte_len);

        if (!new_pass->data) {
                return false;
        }
        talloc_keep_secret(new_pass->data);

        return true;
}


/* encode a wkssvc_PasswordBuffer:
 *
 * similar to samr_CryptPasswordEx. Different: 8byte confounder (instead of
 * 16byte), confounder in front of the 516 byte buffer (instead of after that
 * buffer), calling MD5Update() first with session_key and then with confounder
 * (vice versa in samr) - Guenther */

WERROR encode_wkssvc_join_password_buffer(TALLOC_CTX *mem_ctx,
                                          const char *pwd,
                                          DATA_BLOB *session_key,
                                          struct wkssvc_PasswordBuffer **out_pwd_buf)
{
        struct wkssvc_PasswordBuffer *pwd_buf = NULL;
        uint8_t _confounder[8] = {0};
        DATA_BLOB confounder = data_blob_const(_confounder, 8);
        uint8_t pwbuf[516] = {0};
        DATA_BLOB encrypt_pwbuf = data_blob_const(pwbuf, 516);
        int rc;

        pwd_buf = talloc_zero(mem_ctx, struct wkssvc_PasswordBuffer);
        if (pwd_buf == NULL) {
                return WERR_NOT_ENOUGH_MEMORY;
        }

        encode_pw_buffer(pwbuf, pwd, STR_UNICODE);

        generate_random_buffer(_confounder, sizeof(_confounder));

        rc = samba_gnutls_arcfour_confounded_md5(session_key,
                                                 &confounder,
                                                 &encrypt_pwbuf,
                                                 SAMBA_GNUTLS_ENCRYPT);
        if (rc < 0) {
                ZERO_ARRAY(_confounder);
                TALLOC_FREE(pwd_buf);
                return gnutls_error_to_werror(rc, WERR_CONTENT_BLOCKED);
        }

        memcpy(&pwd_buf->data[0], confounder.data, confounder.length);
        ZERO_ARRAY(_confounder);
        memcpy(&pwd_buf->data[8], encrypt_pwbuf.data, encrypt_pwbuf.length);
        ZERO_ARRAY(pwbuf);

        *out_pwd_buf = pwd_buf;

        return WERR_OK;
}

WERROR decode_wkssvc_join_password_buffer(TALLOC_CTX *mem_ctx,
                                          struct wkssvc_PasswordBuffer *pwd_buf,
                                          DATA_BLOB *session_key,
                                          char **pwd)
{
        uint8_t _confounder[8] = { 0 };
        DATA_BLOB confounder = data_blob_const(_confounder, 8);
        uint8_t pwbuf[516] = {0};
        DATA_BLOB decrypt_pwbuf = data_blob_const(pwbuf, 516);
        bool ok;
        int rc;

        if (pwd_buf == NULL) {
                return WERR_INVALID_PASSWORD;
        }

        *pwd = NULL;

        if (session_key->length != 16) {
                DEBUG(10,("invalid session key\n"));
                return WERR_INVALID_PASSWORD;
        }

        confounder = data_blob_const(&pwd_buf->data[0], 8);
        memcpy(&pwbuf, &pwd_buf->data[8], 516);

        rc = samba_gnutls_arcfour_confounded_md5(session_key,
                                                 &confounder,
                                                 &decrypt_pwbuf,
                                                 SAMBA_GNUTLS_ENCRYPT);
        if (rc < 0) {
                ZERO_ARRAY(_confounder);
                TALLOC_FREE(pwd_buf);
                return gnutls_error_to_werror(rc, WERR_CONTENT_BLOCKED);
        }

        ok = decode_pw_buffer(mem_ctx,
                              decrypt_pwbuf.data,
                              pwd,
                              &decrypt_pwbuf.length,
                              CH_UTF16);
        ZERO_ARRAY(pwbuf);

        if (!ok) {
                return WERR_INVALID_PASSWORD;
        }

        return WERR_OK;
}