feat: add certificate trust configuration for MCP servers

docs/mcp-certificate-trust.md

@@ -0,0 +1,167 @@
+# MCP Server Certificate Trust Configuration
+
+This document describes how to configure certificate trust settings for MCP servers that use HTTPS connections (SSE and StreamableHTTP transports).
+
+## Overview
+
+When connecting to MCP servers over HTTPS, you may encounter servers that use:
+
+- Self-signed certificates
+- Certificates signed by internal/corporate Certificate Authorities (CAs)
+- Certificates that would otherwise be rejected by default Node.js certificate validation
+
+The certificate trust configuration allows you to specify how these certificates should be handled.
+
+## Configuration Options
+
+Certificate trust settings can be added to any SSE or StreamableHTTP server configuration in your MCP settings file.
+
+### Available Options
+
+| Option               | Type    | Default   | Description                                                 |
+| -------------------- | ------- | --------- | ----------------------------------------------------------- |
+| `allowSelfSigned`    | boolean | false     | Allow connections to servers using self-signed certificates |
+| `caCertPath`         | string  | undefined | Path to a CA certificate file (PEM format) to trust         |
+| `rejectUnauthorized` | boolean | true      | Whether to reject unauthorized certificates                 |
+
+## Configuration Examples
+
+### 1. Allow Self-Signed Certificates
+
+```json
+{
+	"mcpServers": {
+		"my-internal-server": {
+			"type": "sse",
+			"url": "https://internal.company.com/mcp",
+			"certificateTrust": {
+				"allowSelfSigned": true
+			}
+		}
+	}
+}
+```
+
+### 2. Trust a Custom CA Certificate
+
+```json
+{
+	"mcpServers": {
+		"corporate-server": {
+			"type": "streamable-http",
+			"url": "https://api.internal.corp/mcp",
+			"certificateTrust": {
+				"caCertPath": "/path/to/company-ca.pem"
+			}
+		}
+	}
+}
+```
+
+### 3. Disable Certificate Validation (Development Only)
+
+⚠️ **Warning**: This configuration disables certificate validation entirely and should only be used in development environments.
+
+```json
+{
+	"mcpServers": {
+		"dev-server": {
+			"type": "sse",
+			"url": "https://dev.local:8443/mcp",
+			"certificateTrust": {
+				"rejectUnauthorized": false
+			}
+		}
+	}
+}
+```
+
+### 4. Combined Configuration
+
+```json
+{
+	"mcpServers": {
+		"complex-server": {
+			"type": "sse",
+			"url": "https://secure.internal.com/mcp",
+			"headers": {
+				"Authorization": "Bearer token"
+			},
+			"certificateTrust": {
+				"allowSelfSigned": true,
+				"caCertPath": "/etc/ssl/certs/internal-ca.pem",
+				"rejectUnauthorized": false
+			}
+		}
+	}
+}
+```
+
+## Obtaining CA Certificates
+
+### From System Certificate Store
+
+On many systems, CA certificates are stored in standard locations:
+
+- **Linux**: `/etc/ssl/certs/` or `/usr/share/ca-certificates/`
+- **macOS**: Can be exported from Keychain Access
+- **Windows**: Can be exported from Certificate Manager (certmgr.msc)
+
+### From Your IT Department
+
+For corporate environments, contact your IT department to obtain:
+
+1. The internal CA certificate (usually in PEM or CRT format)
+2. Instructions on where to save it securely
+3. Any specific certificate validation requirements
+
+### Converting Certificate Formats
+
+If you have a certificate in DER/CER format, convert it to PEM:
+
+```bash
+openssl x509 -inform der -in certificate.cer -out certificate.pem
+```
+
+## Security Considerations
+
+1. **Production Environments**: Always use proper certificates signed by trusted CAs in production.
+
+2. **Certificate Validation**: Only disable `rejectUnauthorized` in development environments where security is not a concern.
+
+3. **CA Certificate Storage**: Store CA certificate files in a secure location with appropriate file permissions.
+
+4. **Regular Updates**: Keep CA certificates up to date, especially for internal CAs that may rotate periodically.
+
+## Troubleshooting
+
+### Common Error Messages
+
+1. **"UNABLE_TO_VERIFY_LEAF_SIGNATURE"**: The server's certificate cannot be verified. Consider adding the CA certificate using `caCertPath`.
+
+2. **"SELF_SIGNED_CERT_IN_CHAIN"**: The certificate chain contains a self-signed certificate. Set `allowSelfSigned: true` if this is expected.
+
+3. **"CERT_HAS_EXPIRED"**: The certificate has expired. Contact the server administrator to renew it.
+
+### Debugging Certificate Issues
+
+To debug certificate issues, you can test the connection using OpenSSL:
+
+```bash
+# View server certificate
+openssl s_client -connect hostname:port -showcerts
+
+# Test with a specific CA certificate
+openssl s_client -connect hostname:port -CAfile /path/to/ca.pem
+```
+
+## Limitations
+
+- Certificate trust settings only apply to SSE and StreamableHTTP transports
+- STDIO transport servers do not use HTTPS and therefore don't need certificate configuration
+- The configuration requires Node.js environment; browser-based implementations may have different requirements
+
+## Related Documentation
+
+- [MCP Server Configuration](./mcp-servers.md)
+- [Model Context Protocol Specification](https://modelcontextprotocol.io)

src/services/mcp/McpHub.ts

@@ -65,6 +65,16 @@ const BaseConfigSchema = z.object({
 	disabledTools: z.array(z.string()).default([]),
 })
 
+// Certificate trust configuration schema
+const CertificateTrustSchema = z.object({
+	// Allow self-signed certificates
+	allowSelfSigned: z.boolean().optional(),
+	// Path to CA certificate file (PEM format)
+	caCertPath: z.string().optional(),
+	// Reject unauthorized certificates (default: true for security)
+	rejectUnauthorized: z.boolean().optional().default(true),
+})
+
 // Custom error messages for better user feedback
 const typeErrorMessage = "Server type must be 'stdio', 'sse', or 'streamable-http'"
 const stdioFieldsErrorMessage =
@@ -102,6 +112,8 @@ const createServerTypeSchema = () => {
 			type: z.enum(["sse"]).optional(),
 			url: z.string().url("URL must be a valid URL format"),
 			headers: z.record(z.string()).optional(),
+			// Certificate trust configuration for HTTPS connections
+			certificateTrust: CertificateTrustSchema.optional(),
 			// Ensure no stdio fields are present
 			command: z.undefined().optional(),
 			args: z.undefined().optional(),
@@ -117,6 +129,8 @@ const createServerTypeSchema = () => {
 			type: z.enum(["streamable-http"]).optional(),
 			url: z.string().url("URL must be a valid URL format"),
 			headers: z.record(z.string()).optional(),
+			// Certificate trust configuration for HTTPS connections
+			certificateTrust: CertificateTrustSchema.optional(),
 			// Ensure no stdio fields are present
 			command: z.undefined().optional(),
 			args: z.undefined().optional(),
@@ -735,10 +749,47 @@ export class McpHub {
 				}
 			} else if (configInjected.type === "streamable-http") {
 				// Streamable HTTP connection
+				const requestInit: RequestInit = {
+					headers: configInjected.headers,
+				}
+
+				// Apply certificate trust settings if configured
+				if (configInjected.certificateTrust) {
+					const { allowSelfSigned, caCertPath, rejectUnauthorized } = configInjected.certificateTrust
+
+					// For Node.js fetch, we need to configure the agent
+					if (typeof process !== "undefined" && process.versions && process.versions.node) {
+						const https = await import("https")
+						const fs = await import("fs/promises")
+
+						const agentOptions: any = {}
+
+						// Handle certificate rejection
+						if (rejectUnauthorized === false || allowSelfSigned === true) {
+							agentOptions.rejectUnauthorized = false
+						}
+
+						// Load CA certificate if provided
+						if (caCertPath) {
+							try {
+								const caCert = await fs.readFile(caCertPath, "utf-8")
+								agentOptions.ca = caCert
+							} catch (error) {
+								console.error(`Failed to load CA certificate from ${caCertPath}:`, error)
+								throw new Error(
+									`Failed to load CA certificate: ${error instanceof Error ? error.message : String(error)}`,
+								)
+							}
+						}
+
+						// Create HTTPS agent with certificate trust settings
+						const agent = new https.Agent(agentOptions)
+						;(requestInit as any).agent = agent
+					}
+				}
+
 				transport = new StreamableHTTPClientTransport(new URL(configInjected.url), {
-					requestInit: {
-						headers: configInjected.headers,
-					},
+					requestInit,
 				})
 
 				// Set up Streamable HTTP specific error handling
@@ -766,18 +817,67 @@ export class McpHub {
 						headers: configInjected.headers,
 					},
 				}
+
 				// Configure ReconnectingEventSource options
-				const reconnectingEventSourceOptions = {
+				const reconnectingEventSourceOptions: any = {
 					max_retry_time: 5000, // Maximum retry time in milliseconds
 					withCredentials: configInjected.headers?.["Authorization"] ? true : false, // Enable credentials if Authorization header exists
-					fetch: (url: string | URL, init: RequestInit) => {
+				}
+
+				// Apply certificate trust settings if configured
+				if (configInjected.certificateTrust) {
+					const { allowSelfSigned, caCertPath, rejectUnauthorized } = configInjected.certificateTrust
+
+					// For Node.js fetch used by ReconnectingEventSource
+					if (typeof process !== "undefined" && process.versions && process.versions.node) {
+						const https = await import("https")
+						const fs = await import("fs/promises")
+
+						const agentOptions: any = {}
+
+						// Handle certificate rejection
+						if (rejectUnauthorized === false || allowSelfSigned === true) {
+							agentOptions.rejectUnauthorized = false
+						}
+
+						// Load CA certificate if provided
+						if (caCertPath) {
+							try {
+								const caCert = await fs.readFile(caCertPath, "utf-8")
+								agentOptions.ca = caCert
+							} catch (error) {
+								console.error(`Failed to load CA certificate from ${caCertPath}:`, error)
+								throw new Error(
+									`Failed to load CA certificate: ${error instanceof Error ? error.message : String(error)}`,
+								)
+							}
+						}
+
+						// Create HTTPS agent with certificate trust settings
+						const agent = new https.Agent(agentOptions)
+
+						// Custom fetch function that includes the HTTPS agent
+						reconnectingEventSourceOptions.fetch = (url: string | URL, init: RequestInit) => {
+							const headers = new Headers({ ...(init?.headers || {}), ...(configInjected.headers || {}) })
+							// Use type assertion for Node.js-specific agent property
+							return fetch(url, {
+								...init,
+								headers,
+								...({ agent } as any),
+							})
+						}
+					}
+				} else {
+					// Default fetch function without certificate trust modifications
+					reconnectingEventSourceOptions.fetch = (url: string | URL, init: RequestInit) => {
 						const headers = new Headers({ ...(init?.headers || {}), ...(configInjected.headers || {}) })
 						return fetch(url, {
 							...init,
 							headers,
 						})
-					},
+					}
 				}
+
 				global.EventSource = ReconnectingEventSource
 				transport = new SSEClientTransport(new URL(configInjected.url), {
 					...sseOptions,