/*
parse a krb5 GSS-API wrapper packet giving a ticket
*/
static bool gensec_gssapi_parse_krb5_wrap(TALLOC_CTX *mem_ctx, const DATA_BLOB *blob, DATA_BLOB *ticket, uint8_t tok_id[2])
{
bool ret;
struct asn1_data *data = asn1_init(mem_ctx);
int data_remaining;
if (!data) {
return false;
}
asn1_load(data, *blob);
asn1_start_tag(data, ASN1_APPLICATION(0));
asn1_check_OID(data, GENSEC_OID_KERBEROS5);
data_remaining = asn1_tag_remaining(data);
if (data_remaining < 3) {
data->has_error = true;
} else {
asn1_read(data, tok_id, 2);
data_remaining -= 2;
*ticket = data_blob_talloc(mem_ctx, NULL, data_remaining);
asn1_read(data, ticket->data, ticket->length);
}
asn1_end_tag(data);
ret = !data->has_error;
asn1_free(data);
return ret;
}
ssize_t read_spnego_data(DATA_BLOB data, SPNEGO_DATA *token)
{
ASN1_DATA asn1;
ssize_t ret = -1;
ZERO_STRUCTP(token);
ZERO_STRUCT(asn1);
asn1_load(&asn1, data);
switch (asn1.data[asn1.ofs]) {
case ASN1_APPLICATION(0):
asn1_start_tag(&asn1, ASN1_APPLICATION(0));
asn1_check_OID(&asn1, OID_SPNEGO);
if (read_negTokenInit(&asn1, &token->negTokenInit)) {
token->type = SPNEGO_NEG_TOKEN_INIT;
}
asn1_end_tag(&asn1);
break;
case ASN1_CONTEXT(1):
if (read_negTokenTarg(&asn1, &token->negTokenTarg)) {
token->type = SPNEGO_NEG_TOKEN_TARG;
}
break;
default:
break;
}
if (!asn1.has_error) ret = asn1.ofs;
asn1_free(&asn1);
return ret;
}
/*
parse a krb5 GSS-API wrapper packet giving a ticket
*/
BOOL spnego_parse_krb5_wrap(DATA_BLOB blob, DATA_BLOB *ticket, uint8 tok_id[2])
{
BOOL ret;
ASN1_DATA data;
int data_remaining;
asn1_load(&data, blob);
asn1_start_tag(&data, ASN1_APPLICATION(0));
asn1_check_OID(&data, OID_KERBEROS5);
data_remaining = asn1_tag_remaining(&data);
if (data_remaining < 3) {
data.has_error = True;
} else {
asn1_read(&data, tok_id, 2);
data_remaining -= 2;
*ticket = data_blob(NULL, data_remaining);
asn1_read(&data, ticket->data, ticket->length);
}
asn1_end_tag(&data);
ret = !data.has_error;
asn1_free(&data);
return ret;
}
/*
parse a spnego NTLMSSP challenge packet giving two security blobs
*/
bool spnego_parse_challenge(TALLOC_CTX *ctx, const DATA_BLOB blob,
DATA_BLOB *chal1, DATA_BLOB *chal2)
{
bool ret = false;
ASN1_DATA *data;
ZERO_STRUCTP(chal1);
ZERO_STRUCTP(chal2);
data = asn1_init(talloc_tos());
if (data == NULL) {
return false;
}
if (!asn1_load(data, blob)) goto err;
if (!asn1_start_tag(data,ASN1_CONTEXT(1))) goto err;
if (!asn1_start_tag(data,ASN1_SEQUENCE(0))) goto err;
if (!asn1_start_tag(data,ASN1_CONTEXT(0))) goto err;
if (!asn1_check_enumerated(data,1)) goto err;
if (!asn1_end_tag(data)) goto err;
if (!asn1_start_tag(data,ASN1_CONTEXT(1))) goto err;
if (!asn1_check_OID(data, OID_NTLMSSP)) goto err;
if (!asn1_end_tag(data)) goto err;
if (!asn1_start_tag(data,ASN1_CONTEXT(2))) goto err;
if (!asn1_read_OctetString(data, ctx, chal1)) goto err;
if (!asn1_end_tag(data)) goto err;
/* the second challenge is optional (XP doesn't send it) */
if (asn1_tag_remaining(data)) {
if (!asn1_start_tag(data,ASN1_CONTEXT(3))) goto err;
if (!asn1_read_OctetString(data, ctx, chal2)) goto err;
if (!asn1_end_tag(data)) goto err;
}
if (!asn1_end_tag(data)) goto err;
if (!asn1_end_tag(data)) goto err;
ret = !asn1_has_error(data);
err:
if (asn1_has_error(data)) {
data_blob_free(chal1);
data_blob_free(chal2);
}
asn1_free(data);
return ret;
}
ssize_t spnego_read_data(TALLOC_CTX *mem_ctx, DATA_BLOB data, struct spnego_data *token)
{
struct asn1_data *asn1;
ssize_t ret = -1;
uint8_t context;
ZERO_STRUCTP(token);
if (data.length == 0) {
return ret;
}
asn1 = asn1_init(mem_ctx);
if (asn1 == NULL) {
return -1;
}
asn1_load(asn1, data);
if (!asn1_peek_uint8(asn1, &context)) {
asn1->has_error = true;
} else {
switch (context) {
case ASN1_APPLICATION(0):
asn1_start_tag(asn1, ASN1_APPLICATION(0));
asn1_check_OID(asn1, GENSEC_OID_SPNEGO);
if (read_negTokenInit(asn1, mem_ctx, &token->negTokenInit)) {
token->type = SPNEGO_NEG_TOKEN_INIT;
}
asn1_end_tag(asn1);
break;
case ASN1_CONTEXT(1):
if (read_negTokenTarg(asn1, mem_ctx, &token->negTokenTarg)) {
token->type = SPNEGO_NEG_TOKEN_TARG;
}
break;
default:
asn1->has_error = true;
break;
}
}
if (!asn1->has_error) ret = asn1->ofs;
asn1_free(asn1);
return ret;
}
/*
magic check a GSS-API wrapper packet for an Kerberos OID
*/
static bool gensec_gssapi_check_oid(const DATA_BLOB *blob, const char *oid)
{
bool ret;
struct asn1_data *data = asn1_init(NULL);
if (!data) return false;
asn1_load(data, *blob);
asn1_start_tag(data, ASN1_APPLICATION(0));
asn1_check_OID(data, oid);
ret = !data->has_error;
asn1_free(data);
return ret;
}
/*
parse a SPNEGO NTLMSSP auth packet. This contains the encrypted passwords
*/
BOOL spnego_parse_auth_response(DATA_BLOB blob, NTSTATUS nt_status,
DATA_BLOB *auth)
{
ASN1_DATA data;
uint8 negResult;
if (NT_STATUS_IS_OK(nt_status)) {
negResult = SPNEGO_NEG_RESULT_ACCEPT;
} else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
negResult = SPNEGO_NEG_RESULT_INCOMPLETE;
} else {
negResult = SPNEGO_NEG_RESULT_REJECT;
}
asn1_load(&data, blob);
asn1_start_tag(&data, ASN1_CONTEXT(1));
asn1_start_tag(&data, ASN1_SEQUENCE(0));
asn1_start_tag(&data, ASN1_CONTEXT(0));
asn1_check_enumerated(&data, negResult);
asn1_end_tag(&data);
if (negResult == SPNEGO_NEG_RESULT_INCOMPLETE) {
asn1_start_tag(&data,ASN1_CONTEXT(1));
asn1_check_OID(&data, OID_NTLMSSP);
asn1_end_tag(&data);
asn1_start_tag(&data,ASN1_CONTEXT(2));
asn1_read_OctetString(&data, auth);
asn1_end_tag(&data);
}
asn1_end_tag(&data);
asn1_end_tag(&data);
if (data.has_error) {
DEBUG(3,("spnego_parse_auth_response failed at %d\n", (int)data.ofs));
asn1_free(&data);
data_blob_free(auth);
return False;
}
asn1_free(&data);
return True;
}
/*
parse a negTokenInit packet giving a GUID, a list of supported
OIDs (the mechanisms) and a principal name string
*/
BOOL spnego_parse_negTokenInit(DATA_BLOB blob,
char *OIDs[ASN1_MAX_OIDS],
char **principal)
{
int i;
BOOL ret;
ASN1_DATA data;
asn1_load(&data, blob);
asn1_start_tag(&data,ASN1_APPLICATION(0));
asn1_check_OID(&data,OID_SPNEGO);
asn1_start_tag(&data,ASN1_CONTEXT(0));
asn1_start_tag(&data,ASN1_SEQUENCE(0));
asn1_start_tag(&data,ASN1_CONTEXT(0));
asn1_start_tag(&data,ASN1_SEQUENCE(0));
for (i=0; asn1_tag_remaining(&data) > 0 && i < ASN1_MAX_OIDS; i++) {
char *oid_str = NULL;
asn1_read_OID(&data,&oid_str);
OIDs[i] = oid_str;
}
OIDs[i] = NULL;
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_start_tag(&data, ASN1_CONTEXT(3));
asn1_start_tag(&data, ASN1_SEQUENCE(0));
asn1_start_tag(&data, ASN1_CONTEXT(0));
asn1_read_GeneralString(&data,principal);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
ret = !data.has_error;
asn1_free(&data);
return ret;
}
/*
parse a negTokenTarg packet giving a list of OIDs and a security blob
*/
BOOL parse_negTokenTarg(DATA_BLOB blob, char *OIDs[ASN1_MAX_OIDS], DATA_BLOB *secblob)
{
int i;
ASN1_DATA data;
asn1_load(&data, blob);
asn1_start_tag(&data, ASN1_APPLICATION(0));
asn1_check_OID(&data,OID_SPNEGO);
asn1_start_tag(&data, ASN1_CONTEXT(0));
asn1_start_tag(&data, ASN1_SEQUENCE(0));
asn1_start_tag(&data, ASN1_CONTEXT(0));
asn1_start_tag(&data, ASN1_SEQUENCE(0));
for (i=0; asn1_tag_remaining(&data) > 0 && i < ASN1_MAX_OIDS; i++) {
char *oid_str = NULL;
asn1_read_OID(&data,&oid_str);
OIDs[i] = oid_str;
}
OIDs[i] = NULL;
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_start_tag(&data, ASN1_CONTEXT(2));
asn1_read_OctetString(&data,secblob);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
if (data.has_error) {
DEBUG(1,("Failed to parse negTokenTarg at offset %d\n", (int)data.ofs));
asn1_free(&data);
return False;
}
asn1_free(&data);
return True;
}
/*
parse a spnego NTLMSSP challenge packet giving two security blobs
*/
BOOL spnego_parse_challenge(const DATA_BLOB blob,
DATA_BLOB *chal1, DATA_BLOB *chal2)
{
BOOL ret;
ASN1_DATA data;
ZERO_STRUCTP(chal1);
ZERO_STRUCTP(chal2);
asn1_load(&data, blob);
asn1_start_tag(&data,ASN1_CONTEXT(1));
asn1_start_tag(&data,ASN1_SEQUENCE(0));
asn1_start_tag(&data,ASN1_CONTEXT(0));
asn1_check_enumerated(&data,1);
asn1_end_tag(&data);
asn1_start_tag(&data,ASN1_CONTEXT(1));
asn1_check_OID(&data, OID_NTLMSSP);
asn1_end_tag(&data);
asn1_start_tag(&data,ASN1_CONTEXT(2));
asn1_read_OctetString(&data, chal1);
asn1_end_tag(&data);
/* the second challenge is optional (XP doesn't send it) */
if (asn1_tag_remaining(&data)) {
asn1_start_tag(&data,ASN1_CONTEXT(3));
asn1_read_OctetString(&data, chal2);
asn1_end_tag(&data);
}
asn1_end_tag(&data);
asn1_end_tag(&data);
ret = !data.has_error;
asn1_free(&data);
return ret;
}
/*
parse a krb5 GSS-API wrapper packet giving a ticket
*/
bool spnego_parse_krb5_wrap(TALLOC_CTX *ctx, DATA_BLOB blob, DATA_BLOB *ticket, uint8 tok_id[2])
{
bool ret;
ASN1_DATA *data;
int data_remaining;
data = asn1_init(talloc_tos());
if (data == NULL) {
return false;
}
asn1_load(data, blob);
asn1_start_tag(data, ASN1_APPLICATION(0));
asn1_check_OID(data, OID_KERBEROS5);
data_remaining = asn1_tag_remaining(data);
if (data_remaining < 3) {
data->has_error = True;
} else {
asn1_read(data, tok_id, 2);
data_remaining -= 2;
*ticket = data_blob_talloc(ctx, NULL, data_remaining);
asn1_read(data, ticket->data, ticket->length);
}
asn1_end_tag(data);
ret = !data->has_error;
if (data->has_error) {
data_blob_free(ticket);
}
asn1_free(data);
return ret;
}
/*
parse a negTokenInit packet giving a GUID, a list of supported
OIDs (the mechanisms) and a principal name string
*/
bool spnego_parse_negTokenInit(TALLOC_CTX *ctx,
DATA_BLOB blob,
char *OIDs[ASN1_MAX_OIDS],
char **principal,
DATA_BLOB *secblob)
{
int i;
bool ret;
ASN1_DATA *data;
data = asn1_init(talloc_tos());
if (data == NULL) {
return false;
}
asn1_load(data, blob);
asn1_start_tag(data,ASN1_APPLICATION(0));
asn1_check_OID(data,OID_SPNEGO);
/* negTokenInit [0] NegTokenInit */
asn1_start_tag(data,ASN1_CONTEXT(0));
asn1_start_tag(data,ASN1_SEQUENCE(0));
/* mechTypes [0] MechTypeList OPTIONAL */
/* Not really optional, we depend on this to decide
* what mechanisms we have to work with. */
asn1_start_tag(data,ASN1_CONTEXT(0));
asn1_start_tag(data,ASN1_SEQUENCE(0));
for (i=0; asn1_tag_remaining(data) > 0 && i < ASN1_MAX_OIDS-1; i++) {
asn1_read_OID(data,ctx, &OIDs[i]);
if (data->has_error) {
break;
}
}
OIDs[i] = NULL;
asn1_end_tag(data);
asn1_end_tag(data);
if (principal) {
*principal = NULL;
}
if (secblob) {
*secblob = data_blob_null;
}
/*
Win7 + Live Sign-in Assistant attaches a mechToken
ASN1_CONTEXT(2) to the negTokenInit packet
which breaks our negotiation if we just assume
the next tag is ASN1_CONTEXT(3).
*/
if (asn1_peek_tag(data, ASN1_CONTEXT(1))) {
uint8 flags;
/* reqFlags [1] ContextFlags OPTIONAL */
asn1_start_tag(data, ASN1_CONTEXT(1));
asn1_start_tag(data, ASN1_BIT_STRING);
while (asn1_tag_remaining(data) > 0) {
asn1_read_uint8(data, &flags);
}
asn1_end_tag(data);
asn1_end_tag(data);
}
if (asn1_peek_tag(data, ASN1_CONTEXT(2))) {
DATA_BLOB sblob = data_blob_null;
/* mechToken [2] OCTET STRING OPTIONAL */
asn1_start_tag(data, ASN1_CONTEXT(2));
asn1_read_OctetString(data, ctx, &sblob);
asn1_end_tag(data);
if (secblob) {
*secblob = sblob;
} else {
data_blob_free(&sblob);
}
}
if (asn1_peek_tag(data, ASN1_CONTEXT(3))) {
char *princ = NULL;
/* mechListMIC [3] OCTET STRING OPTIONAL */
asn1_start_tag(data, ASN1_CONTEXT(3));
asn1_start_tag(data, ASN1_SEQUENCE(0));
asn1_start_tag(data, ASN1_CONTEXT(0));
asn1_read_GeneralString(data, ctx, &princ);
asn1_end_tag(data);
asn1_end_tag(data);
asn1_end_tag(data);
if (principal) {
*principal = princ;
} else {
TALLOC_FREE(princ);
}
}
asn1_end_tag(data);
asn1_end_tag(data);
asn1_end_tag(data);
ret = !data->has_error;
if (data->has_error) {
int j;
if (principal) {
TALLOC_FREE(*principal);
}
if (secblob) {
data_blob_free(secblob);
}
for(j = 0; j < i && j < ASN1_MAX_OIDS-1; j++) {
TALLOC_FREE(OIDs[j]);
}
}
asn1_free(data);
return ret;
}
/*
parse a SPNEGO auth packet. This contains the encrypted passwords
*/
bool spnego_parse_auth_response(TALLOC_CTX *ctx,
DATA_BLOB blob, NTSTATUS nt_status,
const char *mechOID,
DATA_BLOB *auth)
{
ASN1_DATA *data;
uint8 negResult;
if (NT_STATUS_IS_OK(nt_status)) {
negResult = SPNEGO_ACCEPT_COMPLETED;
} else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
negResult = SPNEGO_ACCEPT_INCOMPLETE;
} else {
negResult = SPNEGO_REJECT;
}
data = asn1_init(talloc_tos());
if (data == NULL) {
return false;
}
asn1_load(data, blob);
asn1_start_tag(data, ASN1_CONTEXT(1));
asn1_start_tag(data, ASN1_SEQUENCE(0));
asn1_start_tag(data, ASN1_CONTEXT(0));
asn1_check_enumerated(data, negResult);
asn1_end_tag(data);
*auth = data_blob_null;
if (asn1_tag_remaining(data)) {
asn1_start_tag(data,ASN1_CONTEXT(1));
asn1_check_OID(data, mechOID);
asn1_end_tag(data);
if (asn1_tag_remaining(data)) {
asn1_start_tag(data,ASN1_CONTEXT(2));
asn1_read_OctetString(data, ctx, auth);
asn1_end_tag(data);
}
} else if (negResult == SPNEGO_ACCEPT_INCOMPLETE) {
data->has_error = 1;
}
/* Binding against Win2K DC returns a duplicate of the responseToken in
* the optional mechListMIC field. This is a bug in Win2K. We ignore
* this field if it exists. Win2K8 may return a proper mechListMIC at
* which point we need to implement the integrity checking. */
if (asn1_tag_remaining(data)) {
DATA_BLOB mechList = data_blob_null;
asn1_start_tag(data, ASN1_CONTEXT(3));
asn1_read_OctetString(data, ctx, &mechList);
asn1_end_tag(data);
data_blob_free(&mechList);
DEBUG(5,("spnego_parse_auth_response received mechListMIC, "
"ignoring.\n"));
}
asn1_end_tag(data);
asn1_end_tag(data);
if (data->has_error) {
DEBUG(3,("spnego_parse_auth_response failed at %d\n", (int)data->ofs));
asn1_free(data);
data_blob_free(auth);
return False;
}
asn1_free(data);
return True;
}
