dcesrv_auth.c

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	DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
	return status;
}

/*
  generate a CONNECT level verifier
*/
static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
{
	*blob = data_blob_talloc(mem_ctx, NULL, 16);
	if (blob->data == NULL) {
		return NT_STATUS_NO_MEMORY;
	}
	SIVAL(blob->data, 0, 1);
	memset(blob->data+4, 0, 12);
	return NT_STATUS_OK;
}

/*
  generate a CONNECT level verifier
*/
static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
{
	if (blob->length != 16 ||
	    IVAL(blob->data, 0) != 1) {
		return NT_STATUS_ACCESS_DENIED;
	}
	return NT_STATUS_OK;
}


/*
  check credentials on a request
*/
bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
{
	struct ncacn_packet *pkt = &call->pkt;
	struct dcesrv_connection *dce_conn = call->conn;
	DATA_BLOB auth_blob;
	struct dcerpc_auth auth;
	struct ndr_pull *ndr;
	NTSTATUS status;
	enum ndr_err_code ndr_err;

	if (!dce_conn->auth_state.auth_info ||
	    !dce_conn->auth_state.gensec_security) {
		return true;
	}

	auth_blob.length = 8 + pkt->auth_length;

	/* check for a valid length */
	if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
		return false;
	}

	auth_blob.data = 
		pkt->u.request.stub_and_verifier.data + 
		pkt->u.request.stub_and_verifier.length - auth_blob.length;
	pkt->u.request.stub_and_verifier.length -= auth_blob.length;

	/* pull the auth structure */
	ndr = ndr_pull_init_blob(&auth_blob, call, lp_iconv_convenience(call->conn->dce_ctx->lp_ctx));
	if (!ndr) {
		return false;
	}

	if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
		ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
	}

	ndr_err = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		talloc_free(ndr);
		return false;
	}

	/* check signature or unseal the packet */
	switch (dce_conn->auth_state.auth_info->auth_level) {
	case DCERPC_AUTH_LEVEL_PRIVACY:
		status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
					      call,
					      full_packet->data + DCERPC_REQUEST_LENGTH,
					      pkt->u.request.stub_and_verifier.length, 
					      full_packet->data,
					      full_packet->length-auth.credentials.length,
					      &auth.credentials);
		memcpy(pkt->u.request.stub_and_verifier.data, 
		       full_packet->data + DCERPC_REQUEST_LENGTH,
		       pkt->u.request.stub_and_verifier.length);
		break;

	case DCERPC_AUTH_LEVEL_INTEGRITY:
		status = gensec_check_packet(dce_conn->auth_state.gensec_security,
					     call,
					     pkt->u.request.stub_and_verifier.data, 
					     pkt->u.request.stub_and_verifier.length,
					     full_packet->data,
					     full_packet->length-auth.credentials.length,
					     &auth.credentials);
		break;

	case DCERPC_AUTH_LEVEL_CONNECT:
		status = dcesrv_check_connect_verifier(&auth.credentials);
		break;

	default:
		status = NT_STATUS_INVALID_LEVEL;
		break;
	}

	/* remove the indicated amount of padding */
	if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
		talloc_free(ndr);
		return false;
	}
	pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
	talloc_free(ndr);

	return NT_STATUS_IS_OK(status);
}


/* 
   push a signed or sealed dcerpc request packet into a blob
*/
bool dcesrv_auth_response(struct dcesrv_call_state *call,
			  DATA_BLOB *blob, struct ncacn_packet *pkt)
{
	struct dcesrv_connection *dce_conn = call->conn;
	NTSTATUS status;
	enum ndr_err_code ndr_err;
	struct ndr_push *ndr;
	uint32_t payload_length;
	DATA_BLOB creds2;

	/* non-signed packets are simple */
	if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
		status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
		return NT_STATUS_IS_OK(status);
	}

	ndr = ndr_push_init_ctx(call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx));
	if (!ndr) {
		return false;
	}

	if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
		ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
	}

	ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		return false;
	}

	/* pad to 16 byte multiple, match win2k3 */
	dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 16);
	ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);

	payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;

	if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
		status = dcesrv_connect_verifier(call,
						 &dce_conn->auth_state.auth_info->credentials);
		if (!NT_STATUS_IS_OK(status)) {
			return false;
		}
	} else {

		/* We hope this length is accruate.  If must be if the
		 * GENSEC mech does AEAD signing of the packet
		 * headers */
		dce_conn->auth_state.auth_info->credentials
			= data_blob_talloc(call, NULL, 
					   gensec_sig_size(dce_conn->auth_state.gensec_security, 
							   payload_length));
		data_blob_clear(&dce_conn->auth_state.auth_info->credentials);
	}

	/* add the auth verifier */
	ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
				      dce_conn->auth_state.auth_info);
	if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
		return false;
	}

	/* extract the whole packet as a blob */
	*blob = ndr_push_blob(ndr);

	/* fill in the fragment length and auth_length, we can't fill
	   in these earlier as we don't know the signature length (it
	   could be variable length) */
	dcerpc_set_frag_length(blob, blob->length);

	/* We hope this value is accruate.  If must be if the GENSEC
	 * mech does AEAD signing of the packet headers */
	dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);

	/* sign or seal the packet */
	switch (dce_conn->auth_state.auth_info->auth_level) {
	case DCERPC_AUTH_LEVEL_PRIVACY:
		status = gensec_seal_packet(dce_conn->auth_state.gensec_security, 
					    call,
					    ndr->data + DCERPC_REQUEST_LENGTH, 
					    payload_length,
					    blob->data,
					    blob->length - dce_conn->auth_state.auth_info->credentials.length,
					    &creds2);

		if (NT_STATUS_IS_OK(status)) {
			blob->length -= dce_conn->auth_state.auth_info->credentials.length;
			if (!data_blob_append(call, blob, creds2.data, creds2.length))
				status = NT_STATUS_NO_MEMORY;
			else
				status = NT_STATUS_OK;
		}

		/* If we did AEAD signing of the packet headers, then we hope
		 * this value didn't change... */
		dcerpc_set_auth_length(blob, creds2.length);
		dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
		data_blob_free(&creds2);
		break;

	case DCERPC_AUTH_LEVEL_INTEGRITY:
		status = gensec_sign_packet(dce_conn->auth_state.gensec_security, 
					    call,
					    ndr->data + DCERPC_REQUEST_LENGTH, 
					    payload_length,
					    blob->data,
					    blob->length - dce_conn->auth_state.auth_info->credentials.length,
					    &creds2);
		if (NT_STATUS_IS_OK(status)) {
			blob->length -= dce_conn->auth_state.auth_info->credentials.length;
			if (!data_blob_append(call, blob, creds2.data, creds2.length))
				status = NT_STATUS_NO_MEMORY;
			else
				status = NT_STATUS_OK;
		}

		/* If we did AEAD signing of the packet headers, then we hope
		 * this value didn't change... */
		dcerpc_set_auth_length(blob, creds2.length);
		dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
		data_blob_free(&creds2);
		break;

	case DCERPC_AUTH_LEVEL_CONNECT:
		break;

	default:
		status = NT_STATUS_INVALID_LEVEL;
		break;
	}

	data_blob_free(&dce_conn->auth_state.auth_info->credentials);

	if (!NT_STATUS_IS_OK(status)) {
		return false;
	}	

	return true;
}