Try to create Typeface before writing to config file

This is additional guard for preventing unusable font files for update.

Bug: 187542525
Test: atest FontFamilyUpdateRequestTest
Test: atest FontListParserTest
Test: atest FontManagerTest
Test: atest NativeSystemFontTest
Test: atest PersistentSystemFontConfigTest
Test: atest SystemFontsTest
Test: atest SystemFontsUniqueNameTest
Test: atest UpdatableFontDirTest
Test: atest UpdatableSystemFontTest
Change-Id: I61060e19e0e8c9b1ee992ab85eb93562ea823e5e

services/core/java/com/android/server/graphics/fonts/FontManagerService.java

@@ -21,6 +21,7 @@ import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.content.Context;
 import android.graphics.Typeface;
+import android.graphics.fonts.Font;
 import android.graphics.fonts.FontFamily;
 import android.graphics.fonts.FontFileUtil;
 import android.graphics.fonts.FontManager;
@@ -194,6 +195,13 @@ public final class FontManagerService extends IFontManager.Stub {
             }
         }
 
+        @Override
+        public void tryToCreateTypeface(File file) throws IOException {
+            Font font = new Font.Builder(file).build();
+            FontFamily family = new FontFamily.Builder(font).build();
+            new Typeface.CustomFallbackBuilder(family).build();
+        }
+
         private static ByteBuffer mmap(File file) throws IOException {
             try (FileInputStream in = new FileInputStream(file)) {
                 FileChannel fileChannel = in.getChannel();

services/core/java/com/android/server/graphics/fonts/UpdatableFontDir.java

@@ -68,6 +68,8 @@ final class UpdatableFontDir {
         String buildFontFileName(File file) throws IOException;
 
         long getRevision(File file) throws IOException;
+
+        void tryToCreateTypeface(File file) throws IOException;
     }
 
     /** Interface to mock fs-verity in tests. */
@@ -372,6 +374,16 @@ final class UpdatableFontDir {
                         "Failed to change mode to 711", e);
             }
             FontFileInfo fontFileInfo = validateFontFile(newFontFile);
+
+            // Try to create Typeface and treat as failure something goes wrong.
+            try {
+                mParser.tryToCreateTypeface(fontFileInfo.getFile());
+            } catch (IOException e) {
+                throw new SystemFontException(
+                        FontManager.RESULT_ERROR_INVALID_FONT_FILE,
+                        "Failed to create Typeface from file", e);
+            }
+
             FontConfig fontConfig = getSystemFontConfig();
             if (!addFileToMapIfSameOrNewer(fontFileInfo, fontConfig, false)) {
                 throw new SystemFontException(

services/tests/servicestests/src/com/android/server/graphics/fonts/UpdatableFontDirTest.java

@@ -90,6 +90,10 @@ public final class UpdatableFontDirTest {
             String content = FileUtils.readTextFile(file, 100, "");
             return Long.parseLong(content.split(",")[1]);
         }
+
+        @Override
+        public void tryToCreateTypeface(File file) throws IOException {
+        }
     }
 
     // FakeFsverityUtil will successfully set up fake fs-verity if the signature is GOOD_SIGNATURE.
@@ -717,6 +721,10 @@ public final class UpdatableFontDirTest {
                     public long getRevision(File file) throws IOException {
                         return 0;
                     }
+
+                    @Override
+                    public void tryToCreateTypeface(File file) throws IOException {
+                    }
                 }, fakeFsverityUtil, mConfigFile, mCurrentTimeSupplier, mConfigSupplier);
         dir.loadFontFileMap();
 
@@ -751,6 +759,50 @@ public final class UpdatableFontDirTest {
                     public long getRevision(File file) throws IOException {
                         return 0;
                     }
+
+                    @Override
+                    public void tryToCreateTypeface(File file) throws IOException {
+                    }
+                }, fakeFsverityUtil, mConfigFile, mCurrentTimeSupplier, mConfigSupplier);
+        dir.loadFontFileMap();
+
+        try {
+            dir.update(Collections.singletonList(newFontUpdateRequest("foo.ttf,1,foo",
+                    GOOD_SIGNATURE)));
+            fail("Expect SystemFontException");
+        } catch (FontManagerService.SystemFontException e) {
+            assertThat(e.getErrorCode())
+                    .isEqualTo(FontManager.RESULT_ERROR_INVALID_FONT_FILE);
+        }
+        assertThat(dir.getPostScriptMap()).isEmpty();
+    }
+
+    @Test
+    public void installFontFile_failedToCreateTypeface() throws Exception {
+        FakeFsverityUtil fakeFsverityUtil = new FakeFsverityUtil();
+        FakeFontFileParser parser = new FakeFontFileParser();
+        UpdatableFontDir dir = new UpdatableFontDir(
+                mUpdatableFontFilesDir,
+                new UpdatableFontDir.FontFileParser() {
+                    @Override
+                    public String getPostScriptName(File file) throws IOException {
+                        return parser.getPostScriptName(file);
+                    }
+
+                    @Override
+                    public String buildFontFileName(File file) throws IOException {
+                        return parser.buildFontFileName(file);
+                    }
+
+                    @Override
+                    public long getRevision(File file) throws IOException {
+                        return parser.getRevision(file);
+                    }
+
+                    @Override
+                    public void tryToCreateTypeface(File file) throws IOException {
+                        throw new IOException();
+                    }
                 }, fakeFsverityUtil, mConfigFile, mCurrentTimeSupplier, mConfigSupplier);
         dir.loadFontFileMap();