path is rect track corners

This was triggered by an exploit that started the first
edge well outside the final rectangle, causing the captured
to exceed the correct result.

Ivan observes that we really only want the first and third
corners to compute the bounds, so remove the tracking code
that looks for a valid range of points, and record the
corners instead.

R=robertphillips@google.com
Bug: 824145,skia:7792
Change-Id: If228573d0f05c7158dba8142c144d13834e691ec
Reviewed-on: https://skia-review.googlesource.com/122081
Commit-Queue: Cary Clark <caryclark@skia.org>
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Auto-Submit: Cary Clark <caryclark@skia.org>

1 files changed, 23 insertions, 4 deletions

diff --git a/tests/PathTest.cpp b/tests/PathTest.cpp
index b108b7f1bf..477b02b7c0 100644
--- a/tests/PathTest.cpp
+++ b/tests/PathTest.cpp
@@ -2033,7 +2033,7 @@ static void test_isRect(skiatest::Reporter* reporter) {
         { c3, SK_ARRAY_COUNT(c3), false, true },
 
         { d1, SK_ARRAY_COUNT(d1), false, false },
-        { d2, SK_ARRAY_COUNT(d2), false, false },
+        { d2, SK_ARRAY_COUNT(d2), false, true },
         { d3, SK_ARRAY_COUNT(d3), false, false },
     };
 
@@ -2055,7 +2055,8 @@ static void test_isRect(skiatest::Reporter* reporter) {
             bool isClosed;
             SkPath::Direction direction;
             SkPathPriv::FirstDirection cheapDirection;
-            expected.set(tests[testIndex].fPoints, tests[testIndex].fPointCount);
+            int pointCount = tests[testIndex].fPointCount - (d2 == tests[testIndex].fPoints);
+            expected.set(tests[testIndex].fPoints, pointCount);
             REPORTER_ASSERT(reporter, SkPathPriv::CheapComputeFirstDirection(path, &cheapDirection));
             REPORTER_ASSERT(reporter, path.isRect(&computed, &isClosed, &direction));
             REPORTER_ASSERT(reporter, expected == computed);
@@ -5020,11 +5021,11 @@ DEF_TEST(Path_isRect, reporter) {
     REPORTER_ASSERT(reporter, !path.isRect(&rect));
     // isolated from skbug.com/7792#c39
     SkPath::Verb verbs39[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
-                               SkPath::kLine_Verb  };
+                               SkPath::kLine_Verb };
     SkPoint points39[] = { {150, 75}, {150, 150}, {75, 150}, {75, 100} };
     path = makePath2(points39, verbs39, SK_ARRAY_COUNT(verbs39));
     REPORTER_ASSERT(reporter, !path.isRect(&rect));
-    // from zero_length_paths_aa
+    // isolated from zero_length_paths_aa
     SkPath::Verb verbsAA[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
                                SkPath::kLine_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
                                SkPath::kLine_Verb, SkPath::kClose_Verb };
@@ -5034,4 +5035,22 @@ DEF_TEST(Path_isRect, reporter) {
     REPORTER_ASSERT(reporter, path.isRect(&rect));
     compare.set(&pointsAA[0], SK_ARRAY_COUNT(pointsAA));
     REPORTER_ASSERT(reporter, rect == compare);
+    // isolated from skbug.com/7792#c41
+    SkPath::Verb verbs41[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
+                               SkPath::kLine_Verb, SkPath::kLine_Verb, SkPath::kMove_Verb,
+                               SkPath::kClose_Verb };
+    SkPoint points41[] = { {75, 75}, {150, 75}, {150, 150}, {140, 150}, {140, 75}, {75, 75} };
+    path = makePath2(points41, verbs41, SK_ARRAY_COUNT(verbs41));
+    REPORTER_ASSERT(reporter, path.isRect(&rect));
+    compare.set(&points41[1], 4);
+    REPORTER_ASSERT(reporter, rect == compare);
+    // isolated from skbug.com/7792#c53
+    SkPath::Verb verbs53[] = { SkPath::kMove_Verb, SkPath::kLine_Verb, SkPath::kLine_Verb,
+                               SkPath::kLine_Verb, SkPath::kLine_Verb, SkPath::kMove_Verb,
+                               SkPath::kClose_Verb };
+    SkPoint points53[] = { {75, 75}, {150, 75}, {150, 150}, {140, 150}, {140, 75}, {75, 75} };
+    path = makePath2(points53, verbs53, SK_ARRAY_COUNT(verbs53));
+    REPORTER_ASSERT(reporter, path.isRect(&rect));
+    compare.set(&points53[1], 4);
+    REPORTER_ASSERT(reporter, rect == compare);
 }