Connect: Enable font configuration

web/packages/teleterm/src/services/config/configService.ts

@@ -23,7 +23,7 @@ import { createConfigStore } from './configStore';
 
 const createAppConfigSchema = (platform: Platform) => {
   const defaultKeymap = getDefaultKeymap(platform);
-  const defaultFonts = getDefaultFonts(platform);
+  const defaultTerminalFont = getDefaultTerminalFont(platform);
 
   // Important: all keys except 'usageReporting.enabled' are currently not
   // configurable by the user. Before we let the user configure them,
@@ -85,12 +85,14 @@ const createAppConfigSchema = (platform: Platform) => {
     'keymap.openQuickInput': omitStoredConfigValue(
       z.string().default(defaultKeymap['open-quick-input'])
     ),
-    'fonts.sansSerifFamily': omitStoredConfigValue(
-      z.string().default(defaultFonts['sansSerif'])
-    ),
-    'fonts.monoFamily': omitStoredConfigValue(
-      z.string().default(defaultFonts['mono'])
-    ),
+    /**
+     * This value can be provided by the user and is unsanitized. This means that it cannot be directly interpolated
+     * in a styled component or used in CSS, as it may inject malicious CSS code.
+     * Before using it, sanitize it with `CSS.escape` or pass it as a `style` prop.
+     * Read more https://frontarm.com/james-k-nelson/how-can-i-use-css-in-js-securely/.
+     */
+    'terminal.fontFamily': z.string().default(defaultTerminalFont),
+    'terminal.fontSize': z.number().int().min(1).max(256).default(15),
   });
 };
 
@@ -189,23 +191,14 @@ const getDefaultKeymap = (platform: Platform) => {
   }
 };
 
-function getDefaultFonts(platform: Platform) {
+function getDefaultTerminalFont(platform: Platform) {
   switch (platform) {
     case 'win32':
-      return {
-        sansSerif: "system-ui, 'Segoe WPC', 'Segoe UI', sans-serif",
-        mono: "'Consolas', 'Courier New', monospace",
-      };
+      return "'Consolas', 'Courier New', monospace";
     case 'linux':
-      return {
-        sansSerif: "system-ui, 'Ubuntu', 'Droid Sans', sans-serif",
-        mono: "'Droid Sans Mono', 'Courier New', monospace, 'Droid Sans Fallback'",
-      };
+      return "'Droid Sans Mono', 'Courier New', monospace, 'Droid Sans Fallback'";
     case 'darwin':
-      return {
-        sansSerif: '-apple-system, BlinkMacSystemFont, sans-serif',
-        mono: "Menlo, Monaco, 'Courier New', monospace",
-      };
+      return "Menlo, Monaco, 'Courier New', monospace";
   }
 }
 

web/packages/teleterm/src/ui/App.tsx

@@ -26,24 +26,15 @@ import { AppInitializer } from 'teleterm/ui/AppInitializer';
 import CatchError from './components/CatchError';
 import AppContextProvider from './appContextProvider';
 import AppContext from './appContext';
-import ThemeProvider from './ThemeProvider';
+import { ThemeProvider } from './ThemeProvider';
 
 export const App: React.FC<{ ctx: AppContext }> = ({ ctx }) => {
   return (
     <StyledApp>
       <CatchError>
         <DndProvider backend={HTML5Backend}>
           <AppContextProvider value={ctx}>
-            <ThemeProvider
-              fonts={{
-                mono: ctx.mainProcessClient.configService.get(
-                  'fonts.monoFamily'
-                ).value,
-                sansSerif: ctx.mainProcessClient.configService.get(
-                  'fonts.sansSerifFamily'
-                ).value,
-              }}
-            >
+            <ThemeProvider>
               <AppInitializer />
             </ThemeProvider>
           </AppContextProvider>

web/packages/teleterm/src/ui/DocumentTerminal/DocumentTerminal.tsx

@@ -25,7 +25,7 @@ import {
 import Document from 'teleterm/ui/Document';
 import { useAppContext } from 'teleterm/ui/appContextProvider';
 
-import Terminal from './Terminal';
+import { Terminal } from './Terminal';
 import DocumentReconnect from './DocumentReconnect';
 import useDocTerminal, { Props } from './useDocumentTerminal';
 import { useTshFileTransferHandlers } from './useTshFileTransferHandlers';
@@ -40,10 +40,15 @@ export default function DocumentTerminalContainer({ doc, visible }: Props) {
 
 export function DocumentTerminal(props: Props & { visible: boolean }) {
   const ctx = useAppContext();
+  const { configService } = ctx.mainProcessClient;
   const { visible, doc } = props;
   const state = useDocTerminal(doc);
   const ptyProcess = state.data?.ptyProcess;
   const { upload, download } = useTshFileTransferHandlers();
+  const unsanitizedTerminalFontFamily = configService.get(
+    'terminal.fontFamily'
+  ).value;
+  const terminalFontSize = configService.get('terminal.fontSize').value;
 
   return (
     <Document
@@ -101,6 +106,8 @@ export function DocumentTerminal(props: Props & { visible: boolean }) {
           <Terminal
             ptyProcess={ptyProcess}
             visible={props.visible}
+            unsanitizedFontFamily={unsanitizedTerminalFontFamily}
+            fontSize={terminalFontSize}
             onEnterKey={state.data.refreshTitle}
           />
         </>

web/packages/teleterm/src/ui/DocumentTerminal/Terminal/Terminal.tsx

@@ -15,23 +15,36 @@ limitations under the License.
 */
 
 import React, { useEffect, useRef } from 'react';
-import styled, { useTheme } from 'styled-components';
+import styled from 'styled-components';
 import { Box, Flex } from 'design';
 import { debounce } from 'shared/utils/highbar';
 
 import { IPtyProcess } from 'teleterm/sharedProcess/ptyHost';
 
 import XTermCtrl from './ctrl';
 
-export default function Terminal(props: Props) {
+type TerminalProps = {
+  ptyProcess: IPtyProcess;
+  visible: boolean;
+  /**
+   * This value can be provided by the user and is unsanitized. This means that it cannot be directly interpolated
+   * in a styled component or used in CSS, as it may inject malicious CSS code.
+   * Before using it, sanitize it with `CSS.escape` or pass it as a `style` prop.
+   * Read more https://frontarm.com/james-k-nelson/how-can-i-use-css-in-js-securely/.
+   */
+  unsanitizedFontFamily: string;
+  fontSize: number;
+  onEnterKey?(): void;
+};
+
+export function Terminal(props: TerminalProps) {
   const refElement = useRef<HTMLElement>();
   const refCtrl = useRef<XTermCtrl>();
-  const fontFamily = useTheme().fonts.mono;
 
   useEffect(() => {
     const ctrl = new XTermCtrl(props.ptyProcess, {
       el: refElement.current,
-      fontFamily,
+      fontSize: props.fontSize,
     });
 
     ctrl.open();
@@ -70,17 +83,14 @@ export default function Terminal(props: Props) {
       width="100%"
       style={{ overflow: 'hidden' }}
     >
-      <StyledXterm ref={refElement} />
+      <StyledXterm
+        ref={refElement}
+        style={{ fontFamily: props.unsanitizedFontFamily }}
+      />
     </Flex>
   );
 }
 
-type Props = {
-  ptyProcess: IPtyProcess;
-  visible: boolean;
-  onEnterKey?(): void;
-};
-
 const StyledXterm = styled(Box)`
   height: 100%;
   width: 100%;

web/packages/teleterm/src/ui/DocumentTerminal/Terminal/ctrl.ts

@@ -27,7 +27,7 @@ const WINDOW_RESIZE_DEBOUNCE_DELAY = 200;
 
 type Options = {
   el: HTMLElement;
-  fontFamily?: string;
+  fontSize: number;
 };
 
 export default class TtyTerminal {
@@ -51,7 +51,14 @@ export default class TtyTerminal {
   open(): void {
     this.term = new Terminal({
       cursorBlink: false,
-      fontFamily: this.options.fontFamily,
+      /**
+       * `fontFamily` can be provided by the user and is unsanitized. This means that it cannot be directly used in CSS,
+       * as it may inject malicious CSS code.
+       * To sanitize the value, we set it as a style on the HTML element and then read it from it.
+       * Read more https://frontarm.com/james-k-nelson/how-can-i-use-css-in-js-securely/.
+       */
+      fontFamily: this.el.style.fontFamily,
+      fontSize: this.options.fontSize,
       scrollback: 5000,
       theme: {
         background: theme.colors.primary.darker,

web/packages/teleterm/src/ui/DocumentTerminal/Terminal/index.ts

@@ -14,6 +14,4 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import Terminal from './Terminal';
-
-export default Terminal;
+export { Terminal } from './Terminal';

web/packages/teleterm/src/ui/ThemeProvider/ThemeProvider.tsx

@@ -15,34 +15,21 @@ limitations under the License.
 */
 
 import React from 'react';
-import { ThemeProvider, StyleSheetManager } from 'styled-components';
+import {
+  ThemeProvider as StyledThemeProvider,
+  StyleSheetManager,
+} from 'styled-components';
 
 import { GlobalStyle } from './globals';
 import theme from './theme';
 
-type TeletermThemeProvider = {
-  fonts: {
-    mono: string;
-    sansSerif: string;
-  };
-};
-
-const TeletermThemeProvider: React.FC<TeletermThemeProvider> = props => {
-  if (props?.fonts) {
-    theme.font = props.fonts.sansSerif;
-    theme.fonts = props.fonts;
-  }
-
-  return (
-    <ThemeProvider theme={theme}>
-      <StyleSheetManager disableVendorPrefixes>
-        <React.Fragment>
-          <GlobalStyle />
-          {props.children}
-        </React.Fragment>
-      </StyleSheetManager>
-    </ThemeProvider>
-  );
-};
-
-export default TeletermThemeProvider;
+export const ThemeProvider: React.FC = props => (
+  <StyledThemeProvider theme={theme}>
+    <StyleSheetManager disableVendorPrefixes>
+      <React.Fragment>
+        <GlobalStyle />
+        {props.children}
+      </React.Fragment>
+    </StyleSheetManager>
+  </StyledThemeProvider>
+);

web/packages/teleterm/src/ui/ThemeProvider/index.ts

@@ -14,5 +14,4 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-import ThemeProvider from './ThemeProvider';
-export default ThemeProvider;
+export { ThemeProvider } from './ThemeProvider';

web/packages/teleterm/src/ui/ThemeProvider/theme.ts

@@ -114,11 +114,16 @@ const borders = [
   '32px solid',
 ];
 
+const sansSerif = 'system-ui';
+
 const theme = {
   colors,
   typography,
-  font: fonts.sansSerif,
-  fonts: fonts,
+  font: sansSerif,
+  fonts: {
+    sansSerif,
+    mono: fonts.mono,
+  },
   fontWeights,
   fontSizes,
   space,