commit 6e4ecaf073843e571f4c0a72a0b6d81a01b01607
author Nicolas Pena <npm@chromium.org> Thu May 11 12:33:48 2017 -0400
committer Chromium commit bot <commit-bot@chromium.org> Thu May 11 16:49:55 2017 +0000
tree b85d9996d1f203b3edd8f95603709af77a8d18e1
parent 2a2ee0f1ca747929acaf1b4f2eadbf7c8e8025e6

Stop rendering if a span length overflowed in AGG

In AGG, len is of type coord_type, which we have as int16_t, but we can add to
it large values, causing it to become negative. Stop the rendering when that
occurs.

Bug: chromium:719258
Change-Id: Ic7497666b01220a9cd3e7d749f1fc6ae4a210870
Reviewed-on: https://pdfium-review.googlesource.com/5370
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Nicolás Peña <npm@chromium.org>

core/fxge/agg/fx_agg_driver.cpp

diff --git a/core/fxge/agg/fx_agg_driver.cpp b/core/fxge/agg/fx_agg_driver.cpp
index 471fc9b..128d50c 100644
--- a/core/fxge/agg/fx_agg_driver.cpp
+++ b/core/fxge/agg/fx_agg_driver.cpp
@@ -953,8 +953,10 @@
   unsigned num_spans = sl.num_spans();
   typename Scanline::const_iterator span = sl.begin();
   while (1) {
+    if (span->len <= 0)
+      break;
+
     int x = span->x;
-    ASSERT(span->len > 0);
     uint8_t* dest_pos = nullptr;
     uint8_t* dest_extra_alpha_pos = nullptr;
     uint8_t* ori_pos = nullptr;