Merge pull request microsoft#258805 from microsoft/tyriar/258719

Handle invalid and empty regexps in auto approve parsing

Author: Tyriar

src/vs/workbench/contrib/terminalContrib/chatAgentTools/browser/commandLineAutoApprover.ts

@@ -5,6 +5,7 @@
 
 import { Disposable } from '../../../../../base/common/lifecycle.js';
 import type { OperatingSystem } from '../../../../../base/common/platform.js';
+import { regExpLeadsToEndlessLoop } from '../../../../../base/common/strings.js';
 import { IConfigurationService } from '../../../../../platform/configuration/common/configuration.js';
 import { TerminalChatAgentToolsSettingId } from '../common/terminalChatAgentToolsConfiguration.js';
 import { isPowerShell } from './runInTerminalHelpers.js';
@@ -180,7 +181,21 @@ export class CommandLineAutoApprover extends Disposable {
 			if (flags) {
 				flags = flags.replaceAll('g', '');
 			}
-			return new RegExp(regexPattern, flags || undefined);
+
+			try {
+				const regex = new RegExp(regexPattern, flags || undefined);
+
+				// Check if the regex would lead to an endless loop
+				if (regExpLeadsToEndlessLoop(regex)) {
+					// Return a regex that will never match anything to prevent endless loops
+					return /(?!.*)/;
+				}
+
+				return regex;
+			} catch (error) {
+				// If the regex is invalid, return a regex that will never match anything
+				return /(?!.*)/;
+			}
 		}
 
 		// Escape regex special characters

src/vs/workbench/contrib/terminalContrib/chatAgentTools/test/browser/commandLineAutoApprover.test.ts

@@ -300,6 +300,67 @@ suite('CommandLineAutoApprover', () => {
 			ok(isAutoApproved('pwsh.exe -File D:\\foo.bar\\a-script.ps1'));
 			ok(isAutoApproved('pwsh.exe -File D:\\foo.bar\\a-script.ps1 -AnotherArg'));
 		});
+
+		test('should handle empty regex patterns that could cause endless loops', () => {
+			setAutoApprove({
+				"//": true,
+				"/(?:)/": true,
+				"/*/": true,            // Invalid regex pattern  
+				"/.**/": true           // Invalid regex pattern
+			});
+
+			// These patterns should not cause endless loops and should not match any commands
+			// Invalid patterns should be handled gracefully and not match anything
+			ok(!isAutoApproved('echo hello'));
+			ok(!isAutoApproved('ls'));
+			ok(!isAutoApproved(''));
+		});
+
+		test('should handle regex patterns that would cause endless loops', () => {
+			setAutoApprove({
+				"/a*/": true,
+				"/b?/": true,
+				"/(x|)*/": true,
+				"/(?:)*/": true
+			});
+
+			// Commands should still work normally, endless loop patterns should be safely handled
+			ok(!isAutoApproved('echo hello'));
+			ok(!isAutoApproved('ls'));
+			ok(!isAutoApproved('a'));
+			ok(!isAutoApproved('b'));
+		});
+
+		test('should handle mixed valid and problematic regex patterns', () => {
+			setAutoApprove({
+				"/^echo/": true,        // Valid pattern
+				"//": true,             // Empty pattern
+				"/^ls/": true,          // Valid pattern
+				"/a*/": true,           // Potential endless loop
+				"pwd": true             // Valid string pattern
+			});
+
+			ok(isAutoApproved('echo hello'));
+			ok(isAutoApproved('ls -la'));
+			ok(isAutoApproved('pwd'));
+			ok(!isAutoApproved('rm file'));
+		});
+
+		test('should handle invalid regex patterns gracefully', () => {
+			setAutoApprove({
+				"/*/": true,                    // Invalid regex - nothing to repeat
+				"/(?:+/": true,                 // Invalid regex - incomplete quantifier
+				"/[/": true,                    // Invalid regex - unclosed character class
+				"/^echo/": true,                // Valid pattern
+				"ls": true                      // Valid string pattern
+			});
+
+			// Valid patterns should still work
+			ok(isAutoApproved('echo hello'));
+			ok(isAutoApproved('ls -la'));
+			// Invalid patterns should not match anything and not cause crashes
+			ok(!isAutoApproved('random command'));
+		});
 	});
 
 	suite('PowerShell-specific commands', () => {
@@ -439,6 +500,67 @@ suite('CommandLineAutoApprover', () => {
 			ok(!isCommandLineAutoApproved('npm install --force'));
 			ok(!isCommandLineAutoApproved('powershell -File script.ps1 -ExecutionPolicy Bypass'));
 		});
+
+		test('should handle empty regex patterns with matchCommandLine that could cause endless loops', () => {
+			setAutoApproveWithCommandLine({
+				"//": { approve: true, matchCommandLine: true },
+				"/(?:)/": { approve: true, matchCommandLine: true },
+				"/*/": { approve: true, matchCommandLine: true },            // Invalid regex pattern
+				"/.**/": { approve: true, matchCommandLine: true }           // Invalid regex pattern
+			});
+
+			// These patterns should not cause endless loops and should not match any commands
+			// Invalid patterns should be handled gracefully and not match anything
+			ok(!isCommandLineAutoApproved('echo hello'));
+			ok(!isCommandLineAutoApproved('ls'));
+			ok(!isCommandLineAutoApproved(''));
+		});
+
+		test('should handle regex patterns with matchCommandLine that would cause endless loops', () => {
+			setAutoApproveWithCommandLine({
+				"/a*/": { approve: true, matchCommandLine: true },
+				"/b?/": { approve: true, matchCommandLine: true },
+				"/(x|)*/": { approve: true, matchCommandLine: true },
+				"/(?:)*/": { approve: true, matchCommandLine: true }
+			});
+
+			// Commands should still work normally, endless loop patterns should be safely handled
+			ok(!isCommandLineAutoApproved('echo hello'));
+			ok(!isCommandLineAutoApproved('ls'));
+			ok(!isCommandLineAutoApproved('a'));
+			ok(!isCommandLineAutoApproved('b'));
+		});
+
+		test('should handle mixed valid and problematic regex patterns with matchCommandLine', () => {
+			setAutoApproveWithCommandLine({
+				"/^echo/": { approve: true, matchCommandLine: true },        // Valid pattern
+				"//": { approve: true, matchCommandLine: true },             // Empty pattern
+				"/^ls/": { approve: true, matchCommandLine: true },          // Valid pattern
+				"/a*/": { approve: true, matchCommandLine: true },           // Potential endless loop
+				"pwd": { approve: true, matchCommandLine: true }             // Valid string pattern
+			});
+
+			ok(isCommandLineAutoApproved('echo hello'));
+			ok(isCommandLineAutoApproved('ls -la'));
+			ok(isCommandLineAutoApproved('pwd'));
+			ok(!isCommandLineAutoApproved('rm file'));
+		});
+
+		test('should handle invalid regex patterns with matchCommandLine gracefully', () => {
+			setAutoApproveWithCommandLine({
+				"/*/": { approve: true, matchCommandLine: true },                    // Invalid regex - nothing to repeat
+				"/(?:+/": { approve: true, matchCommandLine: true },                 // Invalid regex - incomplete quantifier  
+				"/[/": { approve: true, matchCommandLine: true },                    // Invalid regex - unclosed character class
+				"/^echo/": { approve: true, matchCommandLine: true },                // Valid pattern
+				"ls": { approve: true, matchCommandLine: true }                      // Valid string pattern
+			});
+
+			// Valid patterns should still work
+			ok(isCommandLineAutoApproved('echo hello'));
+			ok(isCommandLineAutoApproved('ls -la'));
+			// Invalid patterns should not match anything and not cause crashes
+			ok(!isCommandLineAutoApproved('random command'));
+		});
 	});
 
 	suite('reasons', () => {