[PATCH 0/1] MR3398: gdiplus: Prevent infinite loops due to floating point inaccuracy

[Fabian Maurer (＠DarkShadow44)]

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52492

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/3398

[PATCH 1/1] gdiplus: Prevent infinite loops due to floating point inaccuracy

[Fabian Maurer]

From: Fabian Maurer <dark.shadow4(a)web.de>

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52492
---
 dlls/gdiplus/graphicspath.c       |  8 ++++---
 dlls/gdiplus/tests/graphicspath.c | 37 +++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/dlls/gdiplus/graphicspath.c b/dlls/gdiplus/graphicspath.c
index 06e17d4b98a..74a87c6afab 100644
--- a/dlls/gdiplus/graphicspath.c
+++ b/dlls/gdiplus/graphicspath.c
@@ -183,9 +183,11 @@ static BOOL flatten_bezier(path_list_node_t *start, REAL x2, REAL y2, REAL x3, R
         mp[2].X = (mp[1].X + mp[3].X) / 2.0;
         mp[2].Y = (mp[1].Y + mp[3].Y) / 2.0;
 
-        /* Is one pair of the new control points equal to the old control points? */
-        if ((x2 == mp[0].X && y2 == mp[0].Y && x3 == mp[1].X && y3 == mp[1].Y) ||
-            (x2 == mp[3].X && y2 == mp[3].Y && x3 == mp[4].X && y3 == mp[4].Y))
+        /* Test for closely spaced points that don't need to be flattened
+         * Also avoids limited-precision errors in flatness check
+         */
+        if((fabs(pt.X - mp[2].X) + fabs(pt.Y - mp[2].Y) +
+            fabs(pt_st.X - mp[2].X) + fabs(pt_st.Y - mp[2].Y) ) <= flatness / 2)
             continue;
 
         pt = end->pt;
diff --git a/dlls/gdiplus/tests/graphicspath.c b/dlls/gdiplus/tests/graphicspath.c
index 7cbcb51edfc..558eedc147f 100644
--- a/dlls/gdiplus/tests/graphicspath.c
+++ b/dlls/gdiplus/tests/graphicspath.c
@@ -1253,6 +1253,42 @@ static void test_flatten(void)
     GdipDeletePath(path);
 }
 
+static void test_flatten2(void)
+{
+    GpStatus status;
+    GpPath *path;
+
+    status = GdipCreatePath(0, &path);
+    expect(Ok, status);
+    status = GdipStartPathFigure(path);
+    expect(Ok, status);
+
+    /* path seen in the wild that caused a stack overflow */
+    status = GdipAddPathArc(path, -136.33, 20.00, 786.00, 786.00, -105.00, 30.00);
+    expect(Ok, status);
+    status = GdipAddPathArc(path, 256.67, 413.00, 0.00, 0.00, -75.00, -30.00);
+    expect(Ok, status);
+    status = GdipClosePathFigure(path);
+    expect(Ok, status);
+
+    status = GdipFlattenPath(path, NULL, 1.0);
+    expect(Ok, status);
+
+    /* path seen in the wild that caused a stack overflow */
+    /* same path but redo with the manual points that caused a crash */
+    status = GdipResetPath(path);
+    expect(Ok, status);
+    status = GdipAddPathBezier(path, 154.950806, 33.391144, 221.586075, 15.536285, 291.747314, 15.536285, 358.382568, 33.391144);
+    expect(Ok, status);
+    status = GdipAddPathBezier(path, 256.666809, 412.999512, 256.666718, 412.999481, 256.666656, 412.999481, 256.666565, 412.999512);
+    expect(Ok, status);
+    status = GdipClosePathFigure(path);
+    expect(Ok, status);
+    status = GdipFlattenPath(path, NULL, 1.0);
+
+    GdipDeletePath(path);
+}
+
 static path_test_t widenline_path[] = {
     {5.0, 5.0,   PathPointTypeStart, 0, 0}, /*0*/
     {50.0, 5.0,  PathPointTypeLine,  0, 0}, /*1*/
@@ -1935,6 +1971,7 @@ START_TEST(graphicspath)
     test_widen_cap();
     test_isvisible();
     test_empty_rect();
+    test_flatten2();
 
     GdiplusShutdown(gdiplusToken);
 }
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/3398

[PATCH 1/1] gdiplus: Prevent infinite loops due to floating point inaccuracy

[Marvin]

Hi,

It looks like your patch introduced the new failures shown below.
Please investigate and fix them before resubmitting your patch.
If they are not new, fixing them anyway would help a lot. Otherwise
please ask for the known failures list to be updated.

The full results can be found at:
https://testbot.winehq.org/JobDetails.pl?Key=135174

Your paranoid android.


=== build (build log) ===

error: patch failed: dlls/gdiplus/graphicspath.c:183
Task: Patch failed to apply

=== debian11 (build log) ===

error: patch failed: dlls/gdiplus/graphicspath.c:183
Task: Patch failed to apply

=== debian11b (build log) ===

error: patch failed: dlls/gdiplus/graphicspath.c:183
Task: Patch failed to apply