security: strip deceptive Unicode characters from terminal output (#19026)

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

packages/cli/src/ui/components/messages/ToolConfirmationMessage.test.tsx

@@ -8,6 +8,7 @@ import { describe, it, expect, vi } from 'vitest';
 import { ToolConfirmationMessage } from './ToolConfirmationMessage.js';
 import type {
   SerializableConfirmationDetails,
+  ToolCallConfirmationDetails,
   Config,
 } from '@google/gemini-cli-core';
 import { renderWithProviders } from '../../../test-utils/render.js';
@@ -372,4 +373,35 @@ describe('ToolConfirmationMessage', () => {
       unmount();
     });
   });
+
+  it('should strip BiDi characters from MCP tool and server names', async () => {
+    const confirmationDetails: ToolCallConfirmationDetails = {
+      type: 'mcp',
+      title: 'Confirm MCP Tool',
+      serverName: 'test\u202Eserver',
+      toolName: 'test\u202Dtool',
+      toolDisplayName: 'Test Tool',
+      onConfirm: vi.fn(),
+    };
+
+    const { lastFrame, waitUntilReady, unmount } = renderWithProviders(
+      <ToolConfirmationMessage
+        callId="test-call-id"
+        confirmationDetails={confirmationDetails}
+        config={mockConfig}
+        availableTerminalHeight={30}
+        terminalWidth={80}
+      />,
+    );
+    await waitUntilReady();
+
+    const output = lastFrame();
+    // BiDi characters \u202E and \u202D should be stripped
+    expect(output).toContain('MCP Server: testserver');
+    expect(output).toContain('Tool: testtool');
+    expect(output).toContain('Allow execution of MCP tool "testtool"');
+    expect(output).toContain('from server "testserver"?');
+    expect(output).toMatchSnapshot();
+    unmount();
+  });
 });

packages/cli/src/ui/components/messages/ToolConfirmationMessage.tsx

@@ -21,7 +21,10 @@ import type { RadioSelectItem } from '../shared/RadioButtonSelect.js';
 import { useToolActions } from '../../contexts/ToolActionsContext.js';
 import { RadioButtonSelect } from '../shared/RadioButtonSelect.js';
 import { MaxSizedBox, MINIMUM_MAX_HEIGHT } from '../shared/MaxSizedBox.js';
-import { sanitizeForDisplay } from '../../utils/textUtils.js';
+import {
+  sanitizeForDisplay,
+  stripUnsafeCharacters,
+} from '../../utils/textUtils.js';
 import { useKeypress } from '../../hooks/useKeypress.js';
 import { theme } from '../../semantic-colors.js';
 import { useSettings } from '../../contexts/SettingsContext.js';
@@ -324,15 +327,15 @@ export const ToolConfirmationMessage: React.FC<
     } else if (confirmationDetails.type === 'mcp') {
       // mcp tool confirmation
       const mcpProps = confirmationDetails;
-      question = `Allow execution of MCP tool "${mcpProps.toolName}" from server "${mcpProps.serverName}"?`;
+      question = `Allow execution of MCP tool "${sanitizeForDisplay(mcpProps.toolName)}" from server "${sanitizeForDisplay(mcpProps.serverName)}"?`;
     }
 
     if (confirmationDetails.type === 'edit') {
       if (!confirmationDetails.isModifying) {
         bodyContent = (
           <DiffRenderer
-            diffContent={confirmationDetails.fileDiff}
-            filename={confirmationDetails.fileName}
+            diffContent={stripUnsafeCharacters(confirmationDetails.fileDiff)}
+            filename={sanitizeForDisplay(confirmationDetails.fileName)}
             availableTerminalHeight={availableBodyContentHeight()}
             terminalWidth={terminalWidth}
           />
@@ -449,8 +452,12 @@ export const ToolConfirmationMessage: React.FC<
 
       bodyContent = (
         <Box flexDirection="column">
-          <Text color={theme.text.link}>MCP Server: {mcpProps.serverName}</Text>
-          <Text color={theme.text.link}>Tool: {mcpProps.toolName}</Text>
+          <Text color={theme.text.link}>
+            MCP Server: {sanitizeForDisplay(mcpProps.serverName)}
+          </Text>
+          <Text color={theme.text.link}>
+            Tool: {sanitizeForDisplay(mcpProps.toolName)}
+          </Text>
         </Box>
       );
     }

packages/cli/src/ui/components/messages/__snapshots__/ToolConfirmationMessage.test.tsx.snap

@@ -35,6 +35,18 @@ Do you want to proceed?
 "
 `;
 
+exports[`ToolConfirmationMessage > should strip BiDi characters from MCP tool and server names 1`] = `
+"MCP Server: testserver
+Tool: testtool
+Allow execution of MCP tool "testtool" from server "testserver"?
+
+● 1. Allow once
+  2. Allow tool for this session
+  3. Allow all server tools for this session
+  4. No, suggest changes (esc)
+"
+`;
+
 exports[`ToolConfirmationMessage > with folder trust > 'for edit confirmations' > should NOT show "allow always" when folder is untrusted 1`] = `
 "╭──────────────────────────────────────────────────────────────────────────────╮
 │                                                                              │