Initial error handling code

I made it as simple as possible. The impact seems minimal and it should do what's necessary to make this code secure.

BUG=

Committed: http://code.google.com/p/skia/source/detail?r=11247

R=reed@google.com, scroggo@google.com, djsollen@google.com, sugoi@google.com, bsalomon@google.com, mtklein@google.com, senorblanco@google.com, senorblanco@chromium.org

Author: sugoi@chromium.org

Review URL: https://codereview.chromium.org/23021015

git-svn-id: http://skia.googlecode.com/svn/trunk@11922 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 6 insertions, 1 deletions

diff --git a/src/effects/SkMergeImageFilter.cpp b/src/effects/SkMergeImageFilter.cpp
index 7d12ebe06e..a5c32acaf7 100755
--- a/src/effects/SkMergeImageFilter.cpp
+++ b/src/effects/SkMergeImageFilter.cpp
@@ -9,6 +9,7 @@
 #include "SkCanvas.h"
 #include "SkDevice.h"
 #include "SkFlattenableBuffers.h"
+#include "SkValidationUtils.h"
 
 ///////////////////////////////////////////////////////////////////////////////
 
@@ -159,8 +160,12 @@ SkMergeImageFilter::SkMergeImageFilter(SkFlattenableReadBuffer& buffer) : INHERI
     bool hasModes = buffer.readBool();
     if (hasModes) {
         this->initAllocModes();
-        SkASSERT(buffer.getArrayCount() == countInputs() * sizeof(fModes[0]));
+        int nbInputs = countInputs();
+        SkASSERT(buffer.getArrayCount() == nbInputs * sizeof(fModes[0]));
         buffer.readByteArray(fModes);
+        for (int i = 0; i < nbInputs; ++i) {
+            buffer.validate(SkIsValidMode((SkXfermode::Mode)fModes[i]));
+        }
     } else {
         fModes = 0;
     }