From 4b70d1eebba2ddfd692dea6cb5b5457f7c923edf Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 21 Apr 2015 07:54:28 +0100
Subject: [PATCH] prelim-stroke-validate

---
 src/cairo-path-stroke-boxes.c    |  4 ++++
 src/cairo-path-stroke-polygon.c  |  4 ++++
 src/cairo-path-stroke-traps.c    |  4 ++++
 src/cairo-path-stroke-tristrip.c |  4 ++++
 src/cairo-path-stroke.c          |  4 ++++
 src/cairo-stroke-style.c         | 13 +++++++++++++
 src/cairoint.h                   |  4 ++++
 7 files changed, 37 insertions(+)

diff --git a/src/cairo-path-stroke-boxes.c b/src/cairo-path-stroke-boxes.c
index 7f25bf7..6511d23 100644
--- a/src/cairo-path-stroke-boxes.c
+++ b/src/cairo-path-stroke-boxes.c
@@ -619,6 +619,10 @@ _cairo_path_fixed_stroke_rectilinear_to_boxes (const cairo_path_fixed_t	*path,
 
     assert (_cairo_path_fixed_stroke_is_rectilinear (path));
 
+    status = _cairo_stroke_style_fixed_validate (stroke_style, ctm);
+    if (unlikely (status))
+        return status;
+
     if (! _cairo_rectilinear_stroker_init (&rectilinear_stroker,
 					   stroke_style, ctm, antialias,
 					   boxes))
diff --git a/src/cairo-path-stroke-polygon.c b/src/cairo-path-stroke-polygon.c
index e5082bb..f9f7064 100644
--- a/src/cairo-path-stroke-polygon.c
+++ b/src/cairo-path-stroke-polygon.c
@@ -1252,6 +1252,10 @@ _cairo_path_fixed_stroke_to_polygon (const cairo_path_fixed_t	*path,
     struct stroker stroker;
     cairo_status_t status;
 
+    status = _cairo_stroke_style_fixed_validate (style, ctm);
+    if (unlikely (status))
+        return status;
+
     if (style->num_dashes) {
 	return _cairo_path_fixed_stroke_dashed_to_polygon (path,
 							   style,
diff --git a/src/cairo-path-stroke-traps.c b/src/cairo-path-stroke-traps.c
index da54e5a..e183d10 100644
--- a/src/cairo-path-stroke-traps.c
+++ b/src/cairo-path-stroke-traps.c
@@ -92,6 +92,10 @@ stroker_init (struct stroker		*stroker,
 {
     cairo_status_t status;
 
+    status = _cairo_stroke_style_fixed_validate (style, ctm);
+    if (unlikely (status))
+        return status;
+
     stroker->style = style;
     stroker->ctm = ctm;
     stroker->ctm_inverse = NULL;
diff --git a/src/cairo-path-stroke-tristrip.c b/src/cairo-path-stroke-tristrip.c
index 6ce4131..60b662f 100644
--- a/src/cairo-path-stroke-tristrip.c
+++ b/src/cairo-path-stroke-tristrip.c
@@ -1044,6 +1044,10 @@ _cairo_path_fixed_stroke_to_tristrip (const cairo_path_fixed_t	*path,
     if (style->num_dashes)
 	return CAIRO_INT_STATUS_UNSUPPORTED;
 
+    status = _cairo_stroke_style_fixed_validate (style, ctm);
+    if (unlikely (status))
+        return status;
+
     stroker.style = *style;
     stroker.ctm = ctm;
     stroker.ctm_inverse = ctm_inverse;
diff --git a/src/cairo-path-stroke.c b/src/cairo-path-stroke.c
index 4d4ede8..a4e17fd 100644
--- a/src/cairo-path-stroke.c
+++ b/src/cairo-path-stroke.c
@@ -132,6 +132,10 @@ _cairo_stroker_init (cairo_stroker_t		*stroker,
 {
     cairo_status_t status;
 
+    status = _cairo_stroke_style_fixed_validate (stroke_style, ctm);
+    if (unlikely (status))
+	return status;
+
     stroker->style = *stroke_style;
     stroker->ctm = ctm;
     stroker->ctm_inverse = ctm_inverse;
diff --git a/src/cairo-stroke-style.c b/src/cairo-stroke-style.c
index 51c9414..48e98e1 100644
--- a/src/cairo-stroke-style.c
+++ b/src/cairo-stroke-style.c
@@ -83,6 +83,19 @@ _cairo_stroke_style_init_copy (cairo_stroke_style_t *style,
     return CAIRO_STATUS_SUCCESS;
 }
 
+cairo_status_t
+_cairo_stroke_style_fixed_validate (const cairo_stroke_style_t *stroke_style,
+				    const cairo_matrix_t *ctm)
+{
+    double det;
+
+    det = _cairo_matrix_compute_determinant (ctm);
+    if (det * stroke_style->line_width > 1 << (CAIRO_FIXED_BITS - 1))
+	return _cairo_error (CAIRO_STATUS_INVALID_SIZE);
+
+    return CAIRO_STATUS_SUCCESS;
+}
+
 void
 _cairo_stroke_style_fini (cairo_stroke_style_t *style)
 {
diff --git a/src/cairoint.h b/src/cairoint.h
index 5bca003..2602b02 100644
--- a/src/cairoint.h
+++ b/src/cairoint.h
@@ -1264,6 +1264,10 @@ cairo_private cairo_status_t
 _cairo_stroke_style_init_copy (cairo_stroke_style_t *style,
 			       const cairo_stroke_style_t *other);
 
+cairo_private cairo_status_t
+_cairo_stroke_style_fixed_validate (const cairo_stroke_style_t *stroke_style,
+				    const cairo_matrix_t *ctm);
+
 cairo_private void
 _cairo_stroke_style_fini (cairo_stroke_style_t *style);
 
-- 
2.1.4