Checking structure sizes before reading them from memory to avoid overflowing the buffer's stream.

src/core/SkValidatingReadBuffer.cpp

Index: src/core/SkValidatingReadBuffer.cpp
diff --git a/src/core/SkValidatingReadBuffer.cpp b/src/core/SkValidatingReadBuffer.cpp
index a0e1a4179f2cd18ff431203aa8b1091102a68ec7..58f67a0dbec2708a1765737a4f16b0ce9c4789a9 100644
--- a/src/core/SkValidatingReadBuffer.cpp
+++ b/src/core/SkValidatingReadBuffer.cpp
@@ -113,10 +113,10 @@ void SkValidatingReadBuffer::readPoint(SkPoint* point) {
 }
 
 void SkValidatingReadBuffer::readMatrix(SkMatrix* matrix) {
-    const size_t size = matrix->readFromMemory(fReader.peek());
-    fError = fError || (SkAlign4(size) != size);
+    const void* addr = this->skip(SkMatrix::SizeToRead());
     if (!fError) {
-        (void)this->skip(size);
+        const size_t size = matrix->readFromMemory(addr);
+        fError = fError || (SkAlign4(size) != size);
     }
 }
 
@@ -135,18 +135,18 @@ void SkValidatingReadBuffer::readRect(SkRect* rect) {
 }
 
 void SkValidatingReadBuffer::readRegion(SkRegion* region) {
-    const size_t size = region->readFromMemory(fReader.peek());
-    fError = fError || (SkAlign4(size) != size);
+    const void* addr = this->skip(SkRegion::SizeToRead(*this));
     if (!fError) {
-        (void)this->skip(size);
+        const size_t size = region->readFromMemory(addr);
+        fError = fError || (SkAlign4(size) != size);
     }
 }
 
 void SkValidatingReadBuffer::readPath(SkPath* path) {
-    const size_t size = path->readFromMemory(fReader.peek());
-    fError = fError || (SkAlign4(size) != size);
+    const void* addr = this->skip(SkPath::SizeToRead(*this));
     if (!fError) {
-        (void)this->skip(size);
+        const size_t size = path->readFromMemory(addr);
+        fError = fError || (SkAlign4(size) != size);
     }
 }
 
@@ -205,6 +205,8 @@ uint32_t SkValidatingReadBuffer::readScalarArray(SkScalar* values) {
 }
 
 uint32_t SkValidatingReadBuffer::getArrayCount() {
+    const size_t inc = sizeof(uint32_t);
+    fError = fError || !IsPtrAlign4(fReader.peek()) || !fReader.isAvailable(inc);
     return *(uint32_t*)fReader.peek();
 }