commit 181f49c7acb67ad009f6deceb3b5cc0a45220ab4
author djsollen <djsollen@google.com> Mon May 18 13:05:11 2015 -0700
committer Derek Sollenberger <djsollen@google.com> Thu May 21 12:57:20 2015 +0000
tree 8d17e09718abc66b80a668c7d76fcf60c941b63f
parent c8cae184262251418ca3f8a70952805980121d0c

Prevent integer wrap around for malloc size when creating a SkRegion

Review URL: https://codereview.chromium.org/1143603003

bug:20883006
Change-Id: I0472c2b93bdf5f3bf291aaabe11a32e78497dcda

src/core/SkRegionPriv.h

diff --git a/src/core/SkRegionPriv.h b/src/core/SkRegionPriv.h
index c8f000d..00feede 100644
--- a/src/core/SkRegionPriv.h
+++ b/src/core/SkRegionPriv.h
@@ -65,7 +65,10 @@
 
         SkASSERT(count >= SkRegion::kRectRegionRuns);
 
-        RunHead* head = (RunHead*)sk_malloc_throw(sizeof(RunHead) + count * sizeof(RunType));
+        const int64_t size = sk_64_mul(count, sizeof(RunType)) + sizeof(RunHead);
+        if (count < 0 || !sk_64_isS32(size)) { SK_CRASH(); }
+
+        RunHead* head = (RunHead*)sk_malloc_throw(size);
         head->fRefCnt = 1;
         head->fRunCount = count;
         // these must be filled in later, otherwise we will be invalid