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samba-mirror/libcli/auth/smbencrypt.c
Stefan Metzmacher 423e95b430 CVE-2016-2111: libcli/auth: add NTLMv2_RESPONSE_verify_netlogon_creds() helper function
This is the function that prevents spoofing like
Microsoft's CVE-2015-0005.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11749

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Günther Deschner <gd@samba.org>
2016-04-12 19:25:24 +02:00

949 lines
25 KiB
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"
void SMBencrypt_hash(const uint8_t lm_hash[16], const uint8_t *c8, uint8_t p24[24])
{
uint8_t p21[21];
memset(p21,'\0',21);
memcpy(p21, lm_hash, 16);
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
}
/*
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];
ret = E_deshash(passwd, lm_hash);
SMBencrypt_hash(lm_hash, c8, p24);
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 MD5 Hash of a combination of 16 byte salt and 16 byte NT hash.
* @param 16 byte salt.
* @param 16 byte NT hash.
* @param 16 byte return hashed with md5, caller allocated 16 byte buffer
*/
void E_md5hash(const uint8_t salt[16], const uint8_t nthash[16], uint8_t hash_out[16])
{
MD5_CTX tctx;
MD5Init(&tctx);
MD5Update(&tctx, salt, 16);
MD5Update(&tctx, nthash, 16);
MD5Final(hash_out, &tctx);
}
/**
* 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;
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 */
E_P16((const uint8_t *)dospwd, p16);
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;
bool ret;
HMACMD5Context ctx;
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;
}
ret = push_ucs2_talloc(mem_ctx, &user, user_in, &user_byte_len );
if (!ret) {
DEBUG(0, ("push_uss2_talloc() for user failed)\n"));
talloc_free(mem_ctx);
return false;
}
ret = push_ucs2_talloc(mem_ctx, &domain, domain_in, &domain_byte_len);
if (!ret) {
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;
hmac_md5_init_limK_to_64(owf, 16, &ctx);
hmac_md5_update((uint8_t *)user, user_byte_len, &ctx);
hmac_md5_update((uint8_t *)domain, domain_byte_len, &ctx);
hmac_md5_final(kr_buf, &ctx);
#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
talloc_free(mem_ctx);
return true;
}
/* Does the des encryption from the NT or LM MD4 hash. */
void 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);
E_P24(p21, c8, p24);
}
/* Does the des encryption. */
void SMBNTencrypt_hash(const uint8_t nt_hash[16], const uint8_t *c8, uint8_t *p24)
{
uint8_t p21[21];
memset(p21,'\0',21);
memcpy(p21, nt_hash, 16);
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
}
/* Does the NT MD4 hash then des encryption. Plaintext version of the above. */
void SMBNTencrypt(const char *passwd, const uint8_t *c8, uint8_t *p24)
{
uint8_t nt_hash[16];
E_md4hash(passwd, nt_hash);
SMBNTencrypt_hash(nt_hash, c8, p24);
}
/* Does the md5 encryption from the Key Response for NTLMv2. */
void SMBOWFencrypt_ntv2(const uint8_t kr[16],
const DATA_BLOB *srv_chal,
const DATA_BLOB *smbcli_chal,
uint8_t resp_buf[16])
{
HMACMD5Context ctx;
hmac_md5_init_limK_to_64(kr, 16, &ctx);
hmac_md5_update(srv_chal->data, srv_chal->length, &ctx);
hmac_md5_update(smbcli_chal->data, smbcli_chal->length, &ctx);
hmac_md5_final(resp_buf, &ctx);
#ifdef DEBUG_PASSWORD
DEBUG(100, ("SMBOWFencrypt_ntv2: srv_chal, smbcli_chal, resp_buf\n"));
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
}
void SMBsesskeygen_ntv2(const uint8_t kr[16],
const uint8_t * nt_resp, uint8_t sess_key[16])
{
/* a very nice, 128 bit, variable session key */
HMACMD5Context ctx;
hmac_md5_init_limK_to_64(kr, 16, &ctx);
hmac_md5_update(nt_resp, 16, &ctx);
hmac_md5_final((uint8_t *)sess_key, &ctx);
#ifdef DEBUG_PASSWORD
DEBUG(100, ("SMBsesskeygen_ntv2:\n"));
dump_data(100, sess_key, 16);
#endif
}
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
}
void 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];
memcpy(partial_lm_hash, lm_hash, 8);
memset(partial_lm_hash + 8, 0xbd, 6);
des_crypt56(p24, lm_resp, partial_lm_hash, 1);
des_crypt56(p24+8, lm_resp, partial_lm_hash + 7, 1);
memcpy(sess_key, p24, 16);
#ifdef DEBUG_PASSWORD
DEBUG(100, ("SMBsesskeygen_lm_sess_key: \n"));
dump_data(100, sess_key, 16);
#endif
}
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;
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 */
SMBOWFencrypt_ntv2(ntlm_v2_hash, server_chal, &ntlmv2_client_data, ntlmv2_response);
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);
/* 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 */
SMBOWFencrypt_ntv2(ntlm_v2_hash, server_chal, &lmv2_client_data, lmv2_response);
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];
/* 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 */
SMBsesskeygen_ntv2(ntlm_v2_hash, nt_response->data, user_session_key->data);
}
}
/* 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 */
SMBsesskeygen_ntv2(ntlm_v2_hash, lm_response->data, lm_session_key->data);
}
}
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;
}
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);
DEBUG(2,("Failed to parse NTLMv2_RESPONSE "
"length %u - %s - %s\n",
(unsigned)response.length,
ndr_map_error2string(err),
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;
}
/***********************************************************
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)
{
uint8_t new_pw[512];
ssize_t new_pw_len;
/* the incoming buffer can be any alignment. */
string_flags |= STR_NOALIGN;
new_pw_len = push_string(new_pw,
password,
sizeof(new_pw), string_flags);
if (new_pw_len == -1) {
return false;
}
memcpy(&buffer[512 - new_pw_len], new_pw, new_pw_len);
generate_random_buffer(buffer, 512 - new_pw_len);
/*
* The length of the new password is in the last 4 bytes of
* the data buffer.
*/
SIVAL(buffer, 512, new_pw_len);
ZERO_STRUCT(new_pw);
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)
{
int byte_len=0;
*pp_new_pwrd = NULL;
*new_pw_len = 0;
/*
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.
*/
/* 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)) {
DEBUG(0, ("decode_pw_buffer: incorrect password length (%d).\n", byte_len));
DEBUG(0, ("decode_pw_buffer: check that 'encrypt passwords = yes'\n"));
return false;
}
/* decode into the return buffer. */
if (!convert_string_talloc(ctx, string_charset, CH_UNIX,
&in_buffer[512 - byte_len],
byte_len,
(void *)pp_new_pwrd,
new_pw_len)) {
DEBUG(0, ("decode_pw_buffer: failed to convert incoming password\n"));
return false;
}
#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;
}
/***********************************************************
Decode an arc4 encrypted password change buffer.
************************************************************/
void encode_or_decode_arc4_passwd_buffer(unsigned char pw_buf[532], const DATA_BLOB *psession_key)
{
MD5_CTX tctx;
unsigned char key_out[16];
/* Confounder is last 16 bytes. */
MD5Init(&tctx);
MD5Update(&tctx, &pw_buf[516], 16);
MD5Update(&tctx, psession_key->data, psession_key->length);
MD5Final(key_out, &tctx);
/* arc4 with key_out. */
arcfour_crypt(pw_buf, key_out, 516);
}
/***********************************************************
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.
************************************************************/
bool set_pw_in_buffer(uint8_t buffer[516], DATA_BLOB *password)
{
if (password->length > 512) {
return false;
}
memcpy(&buffer[512 - password->length], password->data, password->length);
generate_random_buffer(buffer, 512 - password->length);
/*
* The length of the new password is in the last 4 bytes of
* the data buffer.
*/
SIVAL(buffer, 512, 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;
}
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 */
void encode_wkssvc_join_password_buffer(TALLOC_CTX *mem_ctx,
const char *pwd,
DATA_BLOB *session_key,
struct wkssvc_PasswordBuffer **pwd_buf)
{
uint8_t buffer[516];
MD5_CTX ctx;
struct wkssvc_PasswordBuffer *my_pwd_buf = NULL;
DATA_BLOB confounded_session_key;
int confounder_len = 8;
uint8_t confounder[8];
my_pwd_buf = talloc_zero(mem_ctx, struct wkssvc_PasswordBuffer);
if (!my_pwd_buf) {
return;
}
confounded_session_key = data_blob_talloc(mem_ctx, NULL, 16);
encode_pw_buffer(buffer, pwd, STR_UNICODE);
generate_random_buffer((uint8_t *)confounder, confounder_len);
MD5Init(&ctx);
MD5Update(&ctx, session_key->data, session_key->length);
MD5Update(&ctx, confounder, confounder_len);
MD5Final(confounded_session_key.data, &ctx);
arcfour_crypt_blob(buffer, 516, &confounded_session_key);
memcpy(&my_pwd_buf->data[0], confounder, confounder_len);
memcpy(&my_pwd_buf->data[8], buffer, 516);
data_blob_free(&confounded_session_key);
*pwd_buf = my_pwd_buf;
}
WERROR decode_wkssvc_join_password_buffer(TALLOC_CTX *mem_ctx,
struct wkssvc_PasswordBuffer *pwd_buf,
DATA_BLOB *session_key,
char **pwd)
{
uint8_t buffer[516];
MD5_CTX ctx;
size_t pwd_len;
DATA_BLOB confounded_session_key;
int confounder_len = 8;
uint8_t confounder[8];
*pwd = NULL;
if (!pwd_buf) {
return WERR_INVALID_PASSWORD;
}
if (session_key->length != 16) {
DEBUG(10,("invalid session key\n"));
return WERR_INVALID_PASSWORD;
}
confounded_session_key = data_blob_talloc(mem_ctx, NULL, 16);
memcpy(&confounder, &pwd_buf->data[0], confounder_len);
memcpy(&buffer, &pwd_buf->data[8], 516);
MD5Init(&ctx);
MD5Update(&ctx, session_key->data, session_key->length);
MD5Update(&ctx, confounder, confounder_len);
MD5Final(confounded_session_key.data, &ctx);
arcfour_crypt_blob(buffer, 516, &confounded_session_key);
if (!decode_pw_buffer(mem_ctx, buffer, pwd, &pwd_len, CH_UTF16)) {
data_blob_free(&confounded_session_key);
return WERR_INVALID_PASSWORD;
}
data_blob_free(&confounded_session_key);
return WERR_OK;
}