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https://github.com/samba-team/samba.git
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4e3e323080
Signed-off-by: Stefan Metzmacher <metze@samba.org>
444 lines
10 KiB
C
444 lines
10 KiB
C
/*
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Unix SMB/CIFS implementation.
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simple kerberos5/SPNEGO routines
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Copyright (C) Andrew Tridgell 2001
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Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2002
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Copyright (C) Luke Howard 2003
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Copyright (C) Jeremy Allison 2010
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "includes.h"
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#include "../libcli/auth/spnego.h"
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#include "smb_krb5.h"
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#include "../lib/util/asn1.h"
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/*
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generate a negTokenInit packet given a list of supported
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OIDs (the mechanisms) a blob, and a principal name string
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*/
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DATA_BLOB spnego_gen_negTokenInit(TALLOC_CTX *ctx,
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const char *OIDs[],
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DATA_BLOB *psecblob,
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const char *principal)
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{
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int i;
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ASN1_DATA *data;
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DATA_BLOB ret;
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data = asn1_init(talloc_tos());
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if (data == NULL) {
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return data_blob_null;
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}
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asn1_push_tag(data,ASN1_APPLICATION(0));
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asn1_write_OID(data,OID_SPNEGO);
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asn1_push_tag(data,ASN1_CONTEXT(0));
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asn1_push_tag(data,ASN1_SEQUENCE(0));
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asn1_push_tag(data,ASN1_CONTEXT(0));
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asn1_push_tag(data,ASN1_SEQUENCE(0));
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for (i=0; OIDs[i]; i++) {
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asn1_write_OID(data,OIDs[i]);
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}
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asn1_pop_tag(data);
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asn1_pop_tag(data);
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if (psecblob && psecblob->length && psecblob->data) {
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asn1_push_tag(data, ASN1_CONTEXT(2));
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asn1_write_OctetString(data,psecblob->data,
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psecblob->length);
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asn1_pop_tag(data);
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}
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if (principal) {
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asn1_push_tag(data, ASN1_CONTEXT(3));
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asn1_push_tag(data, ASN1_SEQUENCE(0));
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asn1_push_tag(data, ASN1_CONTEXT(0));
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asn1_write_GeneralString(data,principal);
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asn1_pop_tag(data);
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asn1_pop_tag(data);
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asn1_pop_tag(data);
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}
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asn1_pop_tag(data);
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asn1_pop_tag(data);
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asn1_pop_tag(data);
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if (data->has_error) {
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DEBUG(1,("Failed to build negTokenInit at offset %d\n", (int)data->ofs));
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}
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ret = data_blob_talloc(ctx, data->data, data->length);
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asn1_free(data);
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return ret;
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}
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/*
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parse a negTokenInit packet giving a GUID, a list of supported
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OIDs (the mechanisms) and a principal name string
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*/
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bool spnego_parse_negTokenInit(TALLOC_CTX *ctx,
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DATA_BLOB blob,
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char *OIDs[ASN1_MAX_OIDS],
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char **principal,
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DATA_BLOB *secblob)
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{
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int i;
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bool ret;
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ASN1_DATA *data;
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data = asn1_init(talloc_tos());
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if (data == NULL) {
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return false;
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}
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asn1_load(data, blob);
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asn1_start_tag(data,ASN1_APPLICATION(0));
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asn1_check_OID(data,OID_SPNEGO);
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/* negTokenInit [0] NegTokenInit */
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asn1_start_tag(data,ASN1_CONTEXT(0));
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asn1_start_tag(data,ASN1_SEQUENCE(0));
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/* mechTypes [0] MechTypeList OPTIONAL */
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/* Not really optional, we depend on this to decide
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* what mechanisms we have to work with. */
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asn1_start_tag(data,ASN1_CONTEXT(0));
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asn1_start_tag(data,ASN1_SEQUENCE(0));
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for (i=0; asn1_tag_remaining(data) > 0 && i < ASN1_MAX_OIDS-1; i++) {
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if (!asn1_read_OID(data,ctx, &OIDs[i])) {
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break;
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}
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if (data->has_error) {
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break;
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}
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}
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OIDs[i] = NULL;
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asn1_end_tag(data);
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asn1_end_tag(data);
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if (principal) {
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*principal = NULL;
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}
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if (secblob) {
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*secblob = data_blob_null;
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}
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/*
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Win7 + Live Sign-in Assistant attaches a mechToken
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ASN1_CONTEXT(2) to the negTokenInit packet
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which breaks our negotiation if we just assume
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the next tag is ASN1_CONTEXT(3).
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*/
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if (asn1_peek_tag(data, ASN1_CONTEXT(1))) {
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uint8 flags;
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/* reqFlags [1] ContextFlags OPTIONAL */
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asn1_start_tag(data, ASN1_CONTEXT(1));
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asn1_start_tag(data, ASN1_BIT_STRING);
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while (asn1_tag_remaining(data) > 0) {
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asn1_read_uint8(data, &flags);
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}
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asn1_end_tag(data);
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asn1_end_tag(data);
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}
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if (asn1_peek_tag(data, ASN1_CONTEXT(2))) {
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DATA_BLOB sblob = data_blob_null;
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/* mechToken [2] OCTET STRING OPTIONAL */
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asn1_start_tag(data, ASN1_CONTEXT(2));
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asn1_read_OctetString(data, ctx, &sblob);
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asn1_end_tag(data);
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if (secblob) {
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*secblob = sblob;
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} else {
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data_blob_free(&sblob);
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}
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}
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if (asn1_peek_tag(data, ASN1_CONTEXT(3))) {
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char *princ = NULL;
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/* mechListMIC [3] OCTET STRING OPTIONAL */
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asn1_start_tag(data, ASN1_CONTEXT(3));
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asn1_start_tag(data, ASN1_SEQUENCE(0));
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asn1_start_tag(data, ASN1_CONTEXT(0));
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asn1_read_GeneralString(data, ctx, &princ);
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asn1_end_tag(data);
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asn1_end_tag(data);
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asn1_end_tag(data);
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if (principal) {
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*principal = princ;
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} else {
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TALLOC_FREE(princ);
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}
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}
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asn1_end_tag(data);
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asn1_end_tag(data);
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asn1_end_tag(data);
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ret = !data->has_error;
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if (data->has_error) {
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int j;
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if (principal) {
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TALLOC_FREE(*principal);
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}
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if (secblob) {
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data_blob_free(secblob);
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}
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for(j = 0; j < i && j < ASN1_MAX_OIDS-1; j++) {
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TALLOC_FREE(OIDs[j]);
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}
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}
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asn1_free(data);
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return ret;
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}
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/*
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generate a krb5 GSS-API wrapper packet given a ticket
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*/
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DATA_BLOB spnego_gen_krb5_wrap(TALLOC_CTX *ctx, const DATA_BLOB ticket, const uint8 tok_id[2])
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{
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ASN1_DATA *data;
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DATA_BLOB ret;
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data = asn1_init(talloc_tos());
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if (data == NULL) {
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return data_blob_null;
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}
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asn1_push_tag(data, ASN1_APPLICATION(0));
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asn1_write_OID(data, OID_KERBEROS5);
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asn1_write(data, tok_id, 2);
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asn1_write(data, ticket.data, ticket.length);
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asn1_pop_tag(data);
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if (data->has_error) {
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DEBUG(1,("Failed to build krb5 wrapper at offset %d\n", (int)data->ofs));
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}
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ret = data_blob_talloc(ctx, data->data, data->length);
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asn1_free(data);
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return ret;
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}
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/*
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generate a SPNEGO krb5 negTokenInit packet, ready for a EXTENDED_SECURITY
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kerberos session setup
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*/
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int spnego_gen_krb5_negTokenInit(TALLOC_CTX *ctx,
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const char *principal, int time_offset,
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DATA_BLOB *targ,
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DATA_BLOB *session_key_krb5, uint32 extra_ap_opts,
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time_t *expire_time)
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{
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int retval;
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DATA_BLOB tkt, tkt_wrapped;
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const char *krb_mechs[] = {OID_KERBEROS5_OLD, OID_KERBEROS5, OID_NTLMSSP, NULL};
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/* get a kerberos ticket for the service and extract the session key */
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retval = cli_krb5_get_ticket(ctx, principal, time_offset,
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&tkt, session_key_krb5,
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extra_ap_opts, NULL,
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expire_time, NULL);
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if (retval) {
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return retval;
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}
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/* wrap that up in a nice GSS-API wrapping */
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tkt_wrapped = spnego_gen_krb5_wrap(ctx, tkt, TOK_ID_KRB_AP_REQ);
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/* and wrap that in a shiny SPNEGO wrapper */
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*targ = spnego_gen_negTokenInit(ctx, krb_mechs, &tkt_wrapped, NULL);
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data_blob_free(&tkt_wrapped);
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data_blob_free(&tkt);
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return retval;
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}
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/*
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parse a spnego NTLMSSP challenge packet giving two security blobs
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*/
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bool spnego_parse_challenge(TALLOC_CTX *ctx, const DATA_BLOB blob,
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DATA_BLOB *chal1, DATA_BLOB *chal2)
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{
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bool ret;
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ASN1_DATA *data;
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ZERO_STRUCTP(chal1);
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ZERO_STRUCTP(chal2);
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data = asn1_init(talloc_tos());
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if (data == NULL) {
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return false;
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}
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asn1_load(data, blob);
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asn1_start_tag(data,ASN1_CONTEXT(1));
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asn1_start_tag(data,ASN1_SEQUENCE(0));
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asn1_start_tag(data,ASN1_CONTEXT(0));
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asn1_check_enumerated(data,1);
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asn1_end_tag(data);
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asn1_start_tag(data,ASN1_CONTEXT(1));
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asn1_check_OID(data, OID_NTLMSSP);
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asn1_end_tag(data);
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asn1_start_tag(data,ASN1_CONTEXT(2));
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asn1_read_OctetString(data, ctx, chal1);
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asn1_end_tag(data);
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/* the second challenge is optional (XP doesn't send it) */
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if (asn1_tag_remaining(data)) {
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asn1_start_tag(data,ASN1_CONTEXT(3));
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asn1_read_OctetString(data, ctx, chal2);
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asn1_end_tag(data);
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}
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asn1_end_tag(data);
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asn1_end_tag(data);
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ret = !data->has_error;
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if (data->has_error) {
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data_blob_free(chal1);
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data_blob_free(chal2);
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}
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asn1_free(data);
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return ret;
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}
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/*
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generate a SPNEGO auth packet. This will contain the encrypted passwords
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*/
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DATA_BLOB spnego_gen_auth(TALLOC_CTX *ctx, DATA_BLOB blob)
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{
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ASN1_DATA *data;
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DATA_BLOB ret;
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data = asn1_init(talloc_tos());
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if (data == NULL) {
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return data_blob_null;
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}
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asn1_push_tag(data, ASN1_CONTEXT(1));
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asn1_push_tag(data, ASN1_SEQUENCE(0));
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asn1_push_tag(data, ASN1_CONTEXT(2));
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asn1_write_OctetString(data,blob.data,blob.length);
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asn1_pop_tag(data);
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asn1_pop_tag(data);
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asn1_pop_tag(data);
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ret = data_blob_talloc(ctx, data->data, data->length);
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asn1_free(data);
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return ret;
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}
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/*
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parse a SPNEGO auth packet. This contains the encrypted passwords
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*/
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bool spnego_parse_auth_response(TALLOC_CTX *ctx,
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DATA_BLOB blob, NTSTATUS nt_status,
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const char *mechOID,
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DATA_BLOB *auth)
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{
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ASN1_DATA *data;
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uint8 negResult;
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if (NT_STATUS_IS_OK(nt_status)) {
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negResult = SPNEGO_ACCEPT_COMPLETED;
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} else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
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negResult = SPNEGO_ACCEPT_INCOMPLETE;
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} else {
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negResult = SPNEGO_REJECT;
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}
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data = asn1_init(talloc_tos());
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if (data == NULL) {
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return false;
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}
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asn1_load(data, blob);
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asn1_start_tag(data, ASN1_CONTEXT(1));
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asn1_start_tag(data, ASN1_SEQUENCE(0));
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asn1_start_tag(data, ASN1_CONTEXT(0));
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asn1_check_enumerated(data, negResult);
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asn1_end_tag(data);
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*auth = data_blob_null;
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if (asn1_tag_remaining(data)) {
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asn1_start_tag(data,ASN1_CONTEXT(1));
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asn1_check_OID(data, mechOID);
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asn1_end_tag(data);
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if (asn1_tag_remaining(data)) {
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asn1_start_tag(data,ASN1_CONTEXT(2));
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asn1_read_OctetString(data, ctx, auth);
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asn1_end_tag(data);
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}
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} else if (negResult == SPNEGO_ACCEPT_INCOMPLETE) {
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data->has_error = 1;
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}
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/* Binding against Win2K DC returns a duplicate of the responseToken in
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* the optional mechListMIC field. This is a bug in Win2K. We ignore
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* this field if it exists. Win2K8 may return a proper mechListMIC at
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* which point we need to implement the integrity checking. */
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if (asn1_tag_remaining(data)) {
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DATA_BLOB mechList = data_blob_null;
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asn1_start_tag(data, ASN1_CONTEXT(3));
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asn1_read_OctetString(data, ctx, &mechList);
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asn1_end_tag(data);
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data_blob_free(&mechList);
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DEBUG(5,("spnego_parse_auth_response received mechListMIC, "
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"ignoring.\n"));
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}
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asn1_end_tag(data);
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asn1_end_tag(data);
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if (data->has_error) {
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DEBUG(3,("spnego_parse_auth_response failed at %d\n", (int)data->ofs));
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asn1_free(data);
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data_blob_free(auth);
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return False;
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}
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asn1_free(data);
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return True;
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}
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