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gss_auth.c
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/* Copyright (C) 2014 GSS-NTLMSSP contributors, see COPYING for License */
#include <errno.h>
#include <string.h>
#include "gss_ntlmssp.h"
uint32_t gssntlm_cli_auth(uint32_t *minor_status,
struct gssntlm_ctx *ctx,
struct gssntlm_cred *cred,
struct ntlm_buffer *target_info,
uint32_t in_flags,
gss_channel_bindings_t input_chan_bindings)
{
struct ntlm_buffer nt_chal_resp = { 0 };
struct ntlm_buffer lm_chal_resp = { 0 };
struct ntlm_buffer client_target_info = { 0 };
struct ntlm_key key_exchange_key = { .length = 16 };
struct ntlm_key encrypted_random_session_key = { .length = 16 };
struct ntlm_buffer enc_sess_key = { 0 };
struct ntlm_buffer auth_mic = { NULL, 16 };
uint8_t micbuf[16];
struct ntlm_buffer mic = { micbuf, 16 };
bool add_mic = false;
bool key_exch;
uint32_t retmaj;
uint32_t retmin;
switch (cred->type) {
case GSSNTLM_CRED_USER:
if (ctx->gss_flags & GSS_C_ANON_FLAG) {
/* Anonymous auth, empty responses */
memset(&nt_chal_resp, 0, sizeof(nt_chal_resp));
lm_chal_resp.data = malloc(1);
if (!lm_chal_resp.data) {
set_GSSERR(ENOMEM);
goto done;
}
lm_chal_resp.data[0] = 0;
lm_chal_resp.length = 1;
} else if (gssntlm_sec_v2_ok(ctx)) {
/* ### NTLMv2 ### */
uint8_t client_chal[8];
struct ntlm_buffer cli_chal = { client_chal, 8 };
struct ntlm_key ntlmv2_key = { .length = 16 };
struct ntlm_buffer nt_proof = { 0 };
struct ntlm_buffer cb = { 0 };
uint64_t srv_time = 0;
if (target_info->length == 0 &&
input_chan_bindings != GSS_C_NO_CHANNEL_BINDINGS) {
set_GSSERRS(ERR_NOBINDINGS, GSS_S_BAD_BINDINGS);
goto done;
}
if (target_info->length > 0) {
bool *add_mic_ptr = NULL;
bool protect;
if (input_chan_bindings != GSS_C_NO_CHANNEL_BINDINGS) {
if (input_chan_bindings->initiator_addrtype != 0 ||
input_chan_bindings->initiator_address.length != 0 ||
input_chan_bindings->acceptor_addrtype != 0 ||
input_chan_bindings->acceptor_address.length != 0 ||
input_chan_bindings->application_data.length == 0) {
set_GSSERRS(ERR_BADARG, GSS_S_BAD_BINDINGS);
goto done;
}
cb.length = input_chan_bindings->application_data.length;
cb.data = input_chan_bindings->application_data.value;
}
protect = in_flags & (NTLMSSP_NEGOTIATE_SIGN
| NTLMSSP_NEGOTIATE_SEAL);
if (protect) {
if (ctx->int_flags & NTLMSSP_CTX_FLAG_SPNEGO_CAN_MIC) {
add_mic_ptr = &add_mic;
}
}
retmin = ntlm_process_target_info(
ctx->ntlm, protect, target_info,
ctx->target_name.data.server.name,
&cb, &client_target_info,
&srv_time, add_mic_ptr);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
if (srv_time != 0) {
long int tdiff;
tdiff = ntlm_timestamp_now() - srv_time;
if ((tdiff / 10000000) > MAX_CHALRESP_LIFETIME) {
set_GSSERRS(ERR_TIMESKEW, GSS_S_CONTEXT_EXPIRED);
goto done;
}
}
}
/* Random client challenge */
retmin = RAND_BUFFER(&cli_chal);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
/* NTLMv2 Key */
retmin = NTOWFv2(ctx->ntlm, &cred->cred.user.nt_hash,
cred->cred.user.user.data.user.name,
cred->cred.user.user.data.user.domain,
&ntlmv2_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
/* NTLMv2 Response */
retmin = ntlmv2_compute_nt_response(&ntlmv2_key,
ctx->server_chal, client_chal,
srv_time, &client_target_info,
&nt_chal_resp);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
if (target_info->length == 0) {
/* LMv2 Response
* (only sent if challenge response has no target_info) */
retmin = ntlmv2_compute_lm_response(&ntlmv2_key,
ctx->server_chal,
client_chal,
&lm_chal_resp);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
}
/* The NT proof is the first 16 bytes */
nt_proof.data = nt_chal_resp.data;
nt_proof.length = 16;
/* The Session Base Key */
/* In NTLMv2 the Key Exchange Key is the Session Base Key */
retmin = ntlmv2_session_base_key(&ntlmv2_key, &nt_proof,
&key_exchange_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
} else {
/* ### NTLMv1 ### */
uint8_t client_chal[8];
struct ntlm_buffer cli_chal = { client_chal, 8 };
struct ntlm_key session_base_key = { .length = 16 };
bool NoLMResponseNTLMv1 = !gssntlm_sec_lm_ok(ctx);
bool ext_sec;
nt_chal_resp.length = 24;
nt_chal_resp.data = calloc(1, nt_chal_resp.length);
lm_chal_resp.length = 24;
lm_chal_resp.data = calloc(1, lm_chal_resp.length);
if (!nt_chal_resp.data || !lm_chal_resp.data) {
set_GSSERR(ENOMEM);
goto done;
}
/* Random client challenge */
retmin = RAND_BUFFER(&cli_chal);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
ext_sec = (in_flags & NTLMSSP_NEGOTIATE_EXTENDED_SESSIONSECURITY);
retmin = ntlm_compute_nt_response(&cred->cred.user.nt_hash,
ext_sec, ctx->server_chal,
client_chal, &nt_chal_resp);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
if (!ext_sec && NoLMResponseNTLMv1) {
memcpy(lm_chal_resp.data, nt_chal_resp.data, 24);
} else {
retmin = ntlm_compute_lm_response(&cred->cred.user.lm_hash,
ext_sec, ctx->server_chal,
client_chal, &lm_chal_resp);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
}
retmin = ntlm_session_base_key(&cred->cred.user.nt_hash,
&session_base_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
retmin = KXKEY(ctx->ntlm, ext_sec,
(in_flags & NTLMSSP_NEGOTIATE_LM_KEY),
(in_flags & NTLMSSP_REQUEST_NON_NT_SESSION_KEY),
ctx->server_chal, &cred->cred.user.lm_hash,
&session_base_key, &lm_chal_resp,
&key_exchange_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
}
key_exch = (in_flags & NTLMSSP_NEGOTIATE_KEY_EXCH);
retmin = ntlm_exported_session_key(&key_exchange_key, key_exch,
&ctx->exported_session_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
if (key_exch) {
retmin = ntlm_encrypted_session_key(&key_exchange_key,
&ctx->exported_session_key,
&encrypted_random_session_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
}
/* in_flags all verified, assign as current flags */
ctx->neg_flags |= in_flags;
enc_sess_key.data = encrypted_random_session_key.data;
enc_sess_key.length = encrypted_random_session_key.length;
retmin = ntlm_encode_auth_msg(ctx->ntlm, ctx->neg_flags,
&lm_chal_resp, &nt_chal_resp,
cred->cred.user.user.data.user.domain,
cred->cred.user.user.data.user.name,
ctx->workstation, &enc_sess_key,
add_mic ? &auth_mic : NULL,
&ctx->auth_msg);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
/* Now we need to calculate the MIC, because the MIC is part of the
* message it protects, ntlm_encode_auth_msg() always add a zeroeth
* buffer, however it returns in data_mic the pointer to the actual
* area in the auth_msg that points at the mic, so we can backfill */
if (add_mic) {
retmin = ntlm_mic(&ctx->exported_session_key, &ctx->nego_msg,
&ctx->chal_msg, &ctx->auth_msg, &mic);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
/* now that we have the mic, copy it into the auth message */
memcpy(auth_mic.data, mic.data, 16);
/* Make sure SPNEGO gets to know it has to add mechlistMIC too */
ctx->int_flags |= NTLMSSP_CTX_FLAG_AUTH_WITH_MIC;
}
set_GSSERRS(0, GSS_S_COMPLETE);
break;
case GSSNTLM_CRED_EXTERNAL:
retmin = external_cli_auth(ctx, cred, in_flags, input_chan_bindings);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
set_GSSERRS(0, GSS_S_COMPLETE);
break;
default:
set_GSSERR(ERR_NOUSRCRED);
}
done:
ntlm_free_buffer_data(&client_target_info);
ntlm_free_buffer_data(&nt_chal_resp);
ntlm_free_buffer_data(&lm_chal_resp);
return GSSERR();
}
bool is_ntlm_v1(struct ntlm_buffer *nt_chal_resp)
{
return (nt_chal_resp->length == 24);
}
uint32_t gssntlm_srv_auth(uint32_t *minor_status,
struct gssntlm_ctx *ctx,
struct gssntlm_cred *cred,
struct ntlm_buffer *nt_chal_resp,
struct ntlm_buffer *lm_chal_resp,
struct ntlm_key *key_exchange_key)
{
struct ntlm_key session_base_key = { .length = 16 };
struct ntlm_key ntlmv2_key = { .length = 16 };
struct ntlm_buffer nt_proof = { 0 };
uint32_t retmaj, retmin;
const char *domstr;
bool ntlm_v1;
bool ext_sec;
int retries;
if (key_exchange_key->length != 16) {
return GSSERRS(ERR_KEYLEN, GSS_S_FAILURE);
}
ntlm_v1 = is_ntlm_v1(nt_chal_resp);
if (ntlm_v1 && !gssntlm_sec_lm_ok(ctx) && !gssntlm_sec_ntlm_ok(ctx)) {
return GSSERRS(ERR_NONTLMV1, GSS_S_FAILURE);
}
ext_sec = (ctx->neg_flags & NTLMSSP_NEGOTIATE_EXTENDED_SESSIONSECURITY);
switch (cred->type) {
case GSSNTLM_CRED_USER:
if (ntlm_v1) {
uint8_t client_chal[8] = { 0 };
if (ext_sec) {
memcpy(client_chal, lm_chal_resp->data, 8);
}
retmin = ntlm_verify_nt_response(nt_chal_resp,
&cred->cred.user.nt_hash,
ext_sec, ctx->server_chal,
client_chal);
if (retmin && gssntlm_sec_lm_ok(ctx)) {
retmin = ntlm_verify_lm_response(lm_chal_resp,
&cred->cred.user.lm_hash,
ext_sec, ctx->server_chal,
client_chal);
}
} else for (retries = 2; retries > 0; retries--) {
if (retries == 2) {
domstr = cred->cred.user.user.data.user.domain;
} else {
domstr = NULL;
}
/* NTLMv2 Key */
retmin = NTOWFv2(ctx->ntlm, &cred->cred.user.nt_hash,
cred->cred.user.user.data.user.name,
domstr, &ntlmv2_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
/* NTLMv2 Response */
retmin = ntlmv2_verify_nt_response(nt_chal_resp,
&ntlmv2_key,
ctx->server_chal);
if (retmin && gssntlm_sec_lm_ok(ctx)) {
/* LMv2 Response */
retmin = ntlmv2_verify_lm_response(lm_chal_resp,
&ntlmv2_key,
ctx->server_chal);
}
if (retmin == 0) break;
}
if (retmin) {
set_GSSERR(retmin);
goto done;
}
if (ntlm_v1) {
retmin = ntlm_session_base_key(&cred->cred.user.nt_hash,
&session_base_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
break;
}
/* The NT proof is the first 16 bytes */
nt_proof.data = nt_chal_resp->data;
nt_proof.length = 16;
/* The Session Base Key */
/* In NTLMv2 the Key Exchange Key is the Session Base Key */
retmin = ntlmv2_session_base_key(&ntlmv2_key, &nt_proof,
&session_base_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
break;
case GSSNTLM_CRED_EXTERNAL:
retmin = external_srv_auth(ctx, cred, nt_chal_resp, lm_chal_resp,
&session_base_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
break;
default:
set_GSSERR(ERR_NOUSRCRED);
goto done;
}
if (ntlm_v1) {
retmin = KXKEY(ctx->ntlm, ext_sec,
(ctx->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY),
(ctx->neg_flags & NTLMSSP_REQUEST_NON_NT_SESSION_KEY),
ctx->server_chal, &cred->cred.user.lm_hash,
&session_base_key, lm_chal_resp,
key_exchange_key);
if (retmin) {
set_GSSERR(retmin);
goto done;
}
} else {
memcpy(key_exchange_key->data,
session_base_key.data, session_base_key.length);
}
set_GSSERRS(0, GSS_S_COMPLETE);
done:
return GSSERR();
}