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

src/core/SkPath.cpp

Index: src/core/SkPath.cpp
diff --git a/src/core/SkPath.cpp b/src/core/SkPath.cpp
index 9df62850fd2eb5bc9cf442dc4675b7091cded8c1..c765823ac5ac3c3c725a0303861c626e2b710049 100644
--- a/src/core/SkPath.cpp
+++ b/src/core/SkPath.cpp
@@ -9,6 +9,7 @@
 
 #include "SkBuffer.h"
 #include "SkErrorInternals.h"
+#include "SkFlattenableBuffers.h"
 #include "SkMath.h"
 #include "SkPath.h"
 #include "SkPathRef.h"
@@ -2086,12 +2087,28 @@ SkPath::Verb SkPath::RawIter::next(SkPoint pts[4]) {
     Format in compressed buffer: [ptCount, verbCount, pts[], verbs[]]
 */
 
+uint32_t SkPath::sizeInMemory() const {
+    const int byteCount = sizeof(int32_t) + fPathRef->writeSize();
+    return SkAlign4(byteCount);
+}
+
+uint32_t SkPath::SizeToRead(SkFlattenableReadBuffer& buffer) {
+#ifndef DELETE_THIS_CODE_WHEN_SKPS_ARE_REBUILT_AT_V14_AND_ALL_OTHER_INSTANCES_TOO
+    uint32_t packed = buffer.getArrayCount();
+    bool newFormat = (packed >> kNewFormat_SerializationShift) & 1;
+#endif
+    return sizeof(int32_t) + SkPathRef::SizeToRead(buffer
+#ifndef DELETE_THIS_CODE_WHEN_SKPS_ARE_REBUILT_AT_V14_AND_ALL_OTHER_INSTANCES_TOO
+        , newFormat
+#endif
+    );
+}
+
 uint32_t SkPath::writeToMemory(void* storage) const {
     SkDEBUGCODE(this->validate();)
 
     if (NULL == storage) {
-        const int byteCount = sizeof(int32_t) + fPathRef->writeSize();
-        return SkAlign4(byteCount);
+        return sizeInMemory();
     }
 
     SkWBuffer   buffer(storage);
@@ -2110,7 +2127,9 @@ uint32_t SkPath::writeToMemory(void* storage) const {
     fPathRef->writeToBuffer(&buffer);
 
     buffer.padToAlign4();
-    return SkToU32(buffer.pos());
+    uint32_t writeSize = SkToU32(buffer.pos());
+    SkASSERT(sizeInMemory() == writeSize);
+    return writeSize;
 }
 
 uint32_t SkPath::readFromMemory(const void* storage) {
@@ -2128,16 +2147,18 @@ uint32_t SkPath::readFromMemory(const void* storage) {
 
     fPathRef.reset(SkPathRef::CreateFromBuffer(&buffer
 #ifndef DELETE_THIS_CODE_WHEN_SKPS_ARE_REBUILT_AT_V14_AND_ALL_OTHER_INSTANCES_TOO
-        , newFormat, packed)
+        , newFormat, packed
 #endif
-        );
+        ));
 
     buffer.skipToAlign4();
 
     GEN_ID_INC;
 
     SkDEBUGCODE(this->validate();)
-    return SkToU32(buffer.pos());
+    uint32_t readSize = SkToU32(buffer.pos());
+    SkASSERT(sizeInMemory() == readSize);
+    return readSize;
 }
 
 ///////////////////////////////////////////////////////////////////////////////