Avoid system fonts when fuzzing

This should make reproducing certain fuzzes easier between oss-fuzz
and a typical dev's desktop.

This was the most straight-forward way I could think of to
accomplish this.  An ideal solution would "compile" a set of
fonts that was not the test set and embed it, but I lack the
domain knowledge to craft such a set.

If this method works ok, we can explore making the font set
more robust and varied.

Bug: 818769
Change-Id: I03eb2bc316caf7aec3ffa88e59ff29d76c8557ec
Reviewed-on: https://skia-review.googlesource.com/c/177800
Commit-Queue: Kevin Lubick <kjlubick@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>

5 files changed, 15 insertions, 0 deletions

diff --git a/fuzz/oss_fuzz/FuzzImageFilterDeserialize.cpp b/fuzz/oss_fuzz/FuzzImageFilterDeserialize.cpp
index f9d9598892..7ae7870ee8 100644
--- a/fuzz/oss_fuzz/FuzzImageFilterDeserialize.cpp
+++ b/fuzz/oss_fuzz/FuzzImageFilterDeserialize.cpp
@@ -9,8 +9,10 @@
 #include "SkBitmap.h"
 #include "SkCanvas.h"
 #include "SkData.h"
+#include "SkFontMgrPriv.h"
 #include "SkImageFilter.h"
 #include "SkPaint.h"
+#include "SkTestFontMgr.h"
 
 void FuzzImageFilterDeserialize(sk_sp<SkData> bytes) {
     const int BitmapSize = 24;
@@ -39,6 +41,7 @@ void FuzzImageFilterDeserialize(sk_sp<SkData> bytes) {
 
 #if defined(IS_FUZZING_WITH_LIBFUZZER)
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+    gSkFontMgr_DefaultFactory = &sk_tool_utils::MakePortableFontMgr;
     auto bytes = SkData::MakeWithoutCopy(data, size);
     FuzzImageFilterDeserialize(bytes);
     return 0;
diff --git a/fuzz/oss_fuzz/FuzzMockGPUCanvas.cpp b/fuzz/oss_fuzz/FuzzMockGPUCanvas.cpp
index 539e989f56..5a6f389bee 100644
--- a/fuzz/oss_fuzz/FuzzMockGPUCanvas.cpp
+++ b/fuzz/oss_fuzz/FuzzMockGPUCanvas.cpp
@@ -6,6 +6,8 @@
  */
 
 #include "../Fuzz.h"
+#include "SkTestFontMgr.h"
+#include "SkFontMgrPriv.h"
 
 void fuzz_MockGPUCanvas(Fuzz* f);
 
@@ -18,6 +20,7 @@ extern "C" {
     }
 
     int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+        gSkFontMgr_DefaultFactory = &sk_tool_utils::MakePortableFontMgr;
         auto fuzz = Fuzz(SkData::MakeWithoutCopy(data, size));
         fuzz_MockGPUCanvas(&fuzz);
         return 0;
diff --git a/fuzz/oss_fuzz/FuzzNullCanvas.cpp b/fuzz/oss_fuzz/FuzzNullCanvas.cpp
index 37f32881a9..2363af8dab 100644
--- a/fuzz/oss_fuzz/FuzzNullCanvas.cpp
+++ b/fuzz/oss_fuzz/FuzzNullCanvas.cpp
@@ -6,10 +6,13 @@
  */
 
 #include "../Fuzz.h"
+#include "SkTestFontMgr.h"
+#include "SkFontMgrPriv.h"
 
 void fuzz_NullCanvas(Fuzz* f);
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+    gSkFontMgr_DefaultFactory = &sk_tool_utils::MakePortableFontMgr;
     auto fuzz = Fuzz(SkData::MakeWithoutCopy(data, size));
     fuzz_NullCanvas(&fuzz);
     return 0;
diff --git a/fuzz/oss_fuzz/FuzzRasterN32Canvas.cpp b/fuzz/oss_fuzz/FuzzRasterN32Canvas.cpp
index 24d74a5cd6..8038cf5a98 100644
--- a/fuzz/oss_fuzz/FuzzRasterN32Canvas.cpp
+++ b/fuzz/oss_fuzz/FuzzRasterN32Canvas.cpp
@@ -6,10 +6,13 @@
  */
 
 #include "../Fuzz.h"
+#include "SkTestFontMgr.h"
+#include "SkFontMgrPriv.h"
 
 void fuzz_RasterN32Canvas(Fuzz* f);
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+    gSkFontMgr_DefaultFactory = &sk_tool_utils::MakePortableFontMgr;
     auto fuzz = Fuzz(SkData::MakeWithoutCopy(data, size));
     fuzz_RasterN32Canvas(&fuzz);
     return 0;
diff --git a/fuzz/oss_fuzz/FuzzTextBlobDeserialize.cpp b/fuzz/oss_fuzz/FuzzTextBlobDeserialize.cpp
index de68bcc5ff..6b82c79358 100644
--- a/fuzz/oss_fuzz/FuzzTextBlobDeserialize.cpp
+++ b/fuzz/oss_fuzz/FuzzTextBlobDeserialize.cpp
@@ -6,9 +6,11 @@
  */
 
 #include "SkCanvas.h"
+#include "SkFontMgrPriv.h"
 #include "SkPaint.h"
 #include "SkReadBuffer.h"
 #include "SkSurface.h"
+#include "SkTestFontMgr.h"
 #include "SkTextBlobPriv.h"
 
 void FuzzTextBlobDeserialize(SkReadBuffer& buf) {
@@ -27,6 +29,7 @@ void FuzzTextBlobDeserialize(SkReadBuffer& buf) {
 
 #if defined(IS_FUZZING_WITH_LIBFUZZER)
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+    gSkFontMgr_DefaultFactory = &sk_tool_utils::MakePortableFontMgr;
     SkReadBuffer buf(data, size);
     FuzzTextBlobDeserialize(buf);
     return 0;