PermissionChecker.ts

import type { INode, Workflow } from 'n8n-workflow';
import { NodeOperationError, WorkflowOperationError } from 'n8n-workflow';
import config from '@/config';
import { isSharingEnabled } from './UserManagementHelper';
import { OwnershipService } from '@/services/ownership.service';
import Container from 'typedi';
import { RoleService } from '@/services/role.service';
import { UserRepository } from '@db/repositories/user.repository';
import { SharedCredentialsRepository } from '@db/repositories/sharedCredentials.repository';
import { SharedWorkflowRepository } from '@db/repositories/sharedWorkflow.repository';

export class PermissionChecker {
	/**
	 * Check if a user is permitted to execute a workflow.
	 */
	static async check(workflow: Workflow, userId: string) {
		// allow if no nodes in this workflow use creds

		const credIdsToNodes = PermissionChecker.mapCredIdsToNodes(workflow);

		const workflowCredIds = Object.keys(credIdsToNodes);

		if (workflowCredIds.length === 0) return;

		// allow if requesting user is instance owner

		const user = await Container.get(UserRepository).findOneOrFail({
			where: { id: userId },
			relations: ['globalRole'],
		});

		if (user.hasGlobalScope('workflow:execute')) return;

		// allow if all creds used in this workflow are a subset of
		// all creds accessible to users who have access to this workflow

		let workflowUserIds = [userId];

		if (workflow.id && isSharingEnabled()) {
			const workflowSharings = await Container.get(SharedWorkflowRepository).find({
				relations: ['workflow'],
				where: { workflowId: workflow.id },
				select: ['userId'],
			});
			workflowUserIds = workflowSharings.map((s) => s.userId);
		}

		const roleId = await Container.get(RoleService).findCredentialOwnerRoleId();

		const credentialSharings = await Container.get(SharedCredentialsRepository).findSharings(
			workflowUserIds,
			roleId,
		);

		const accessibleCredIds = credentialSharings.map((s) => s.credentialsId);

		const inaccessibleCredIds = workflowCredIds.filter((id) => !accessibleCredIds.includes(id));

		if (inaccessibleCredIds.length === 0) return;

		// if disallowed, flag only first node using first inaccessible cred

		const nodeToFlag = credIdsToNodes[inaccessibleCredIds[0]][0];

		throw new NodeOperationError(nodeToFlag, 'Node has no access to credential', {
			description: 'Please recreate the credential or ask its owner to share it with you.',
			level: 'warning',
		});
	}

	static async checkSubworkflowExecutePolicy(
		subworkflow: Workflow,
		parentWorkflowId: string,
		node?: INode,
	) {
		/**
		 * Important considerations: both the current workflow and the parent can have empty IDs.
		 * This happens when a user is executing an unsaved workflow manually running a workflow
		 * loaded from a file or code, for instance.
		 * This is an important topic to keep in mind for all security checks
		 */
		if (!subworkflow.id) {
			// It's a workflow from code and not loaded from DB
			// No checks are necessary since it doesn't have any sort of settings
			return;
		}

		let policy =
			subworkflow.settings?.callerPolicy ?? config.getEnv('workflows.callerPolicyDefaultOption');

		if (!isSharingEnabled()) {
			// Community version allows only same owner workflows
			policy = 'workflowsFromSameOwner';
		}

		const parentWorkflowOwner =
			await Container.get(OwnershipService).getWorkflowOwnerCached(parentWorkflowId);

		const subworkflowOwner = await Container.get(OwnershipService).getWorkflowOwnerCached(
			subworkflow.id,
		);

		const description =
			subworkflowOwner.id === parentWorkflowOwner.id
				? 'Change the settings of the sub-workflow so it can be called by this one.'
				: `${subworkflowOwner.firstName} (${subworkflowOwner.email}) can make this change. You may need to tell them the ID of the sub-workflow, which is ${subworkflow.id}`;

		const errorToThrow = new WorkflowOperationError(
			`Target workflow ID ${subworkflow.id} may not be called`,
			node,
			description,
		);

		if (policy === 'none') {
			throw errorToThrow;
		}

		if (policy === 'workflowsFromAList') {
			if (parentWorkflowId === undefined) {
				throw errorToThrow;
			}
			const allowedCallerIds = subworkflow.settings.callerIds
				?.split(',')
				.map((id) => id.trim())
				.filter((id) => id !== '');

			if (!allowedCallerIds?.includes(parentWorkflowId)) {
				throw errorToThrow;
			}
		}

		if (policy === 'workflowsFromSameOwner' && subworkflowOwner?.id !== parentWorkflowOwner.id) {
			throw errorToThrow;
		}
	}

	private static mapCredIdsToNodes(workflow: Workflow) {
		return Object.values(workflow.nodes).reduce<{ [credentialId: string]: INode[] }>(
			(map, node) => {
				if (node.disabled || !node.credentials) return map;

				Object.values(node.credentials).forEach((cred) => {
					if (!cred.id) {
						throw new NodeOperationError(node, 'Node uses invalid credential', {
							description: 'Please recreate the credential.',
							level: 'warning',
						});
					}

					map[cred.id] = map[cred.id] ? [...map[cred.id], node] : [node];
				});

				return map;
			},
			{},
		);
	}
}