commit 9d5c6743f614973bd241cde451ad2d1d6c31525b
author Mike Reed <reed@google.com> Tue Mar 06 10:31:27 2018 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Tue Mar 06 15:51:16 2018 +0000
tree 4b17aa12efefbafc4f22422f6787536635f2b938
parent eb3f674d6ddd88e4a31570b26f61238b4b82f490

check for valid inputs to shadows

Bug: oss-fuzz:6766
Change-Id: I6b131d53564618bb2be50fa38a1c9fdf15deff05
Reviewed-on: https://skia-review.googlesource.com/112483
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Mike Reed <reed@google.com>

src/utils/SkShadowTessellator.cpp

diff --git a/src/utils/SkShadowTessellator.cpp b/src/utils/SkShadowTessellator.cpp
index 2375429..8815ce6 100755
--- a/src/utils/SkShadowTessellator.cpp
+++ b/src/utils/SkShadowTessellator.cpp
@@ -379,9 +379,7 @@
         , fSplitFirstEdge(false)
         , fSplitPreviousEdge(false) {
     // TODO: support some concave paths
-    if (!path.isConvex()) {
-        return;
-    }
+    SkASSERT(path.isConvex());
 
     // Set base colors
     SkScalar umbraAlpha = SkScalarInvert(SkDrawShadowMetrics::AmbientRecipAlpha(heightFunc(0, 0)));
@@ -807,9 +805,7 @@
     , fValidUmbra(true) {
 
     // TODO: support some concave paths
-    if (!path.isConvex()) {
-        return;
-    }
+    SkASSERT(path.isConvex());
 
     // make sure we're not below the canvas plane
     if (this->setZOffset(path.getBounds(), ctm.hasPerspective())) {
@@ -1414,6 +1410,9 @@
 
 sk_sp<SkVertices> SkShadowTessellator::MakeAmbient(const SkPath& path, const SkMatrix& ctm,
                                                    const SkPoint3& zPlane, bool transparent) {
+    if (!path.isFinite() || !path.isConvex() || !ctm.isFinite() || !zPlane.isFinite()) {
+        return nullptr;
+    }
     SkAmbientShadowTessellator ambientTess(path, ctm, zPlane, transparent);
     return ambientTess.releaseVertices();
 }
@@ -1421,6 +1420,10 @@
 sk_sp<SkVertices> SkShadowTessellator::MakeSpot(const SkPath& path, const SkMatrix& ctm,
                                                 const SkPoint3& zPlane, const SkPoint3& lightPos,
                                                 SkScalar lightRadius,  bool transparent) {
+    if (!path.isFinite() || !path.isConvex() || !ctm.isFinite() || !zPlane.isFinite() ||
+        !lightPos.isFinite() || !SkScalarIsFinite(lightRadius) || !(lightRadius > 0)) {
+        return nullptr;
+    }
     SkSpotShadowTessellator spotTess(path, ctm, zPlane, lightPos, lightRadius, transparent);
     return spotTess.releaseVertices();
 }