commit 2157d8fa6f7e12063ca166476ed2223d24234db7
author Ben Wagner <bungeman@google.com> Tue Apr 24 10:29:19 2018 +0200
committer Werner Lemberg <wl@gnu.org> Tue Apr 24 10:29:19 2018 +0200
tree a4a94df9710c34f1ad6fe22c3e19f2f7efa5713e
parent 67697d0076cbd2e59ee22c665b2ee792ef5b54ae

[base] Avoid undefined behaviour in lcd filtering code (#53727).

* src/base/ftlcdfil.c (ft_lcd_filter_fir, _ft_lcd_filter_legacy):
Ensure `height > 0'.

ChangeLog

diff --git a/ChangeLog b/ChangeLog
index 690d074..cd8b153 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2018-04-24  Ben Wagner  <bungeman@google.com>
+
+	[base] Avoid undefined behaviour in lcd filtering code (#53727).
+
+	* src/base/ftlcdfil.c (ft_lcd_filter_fir, _ft_lcd_filter_legacy):
+	Ensure `height > 0'.
+
 2018-04-22  Werner Lemberg  <wl@gnu.org>
 
 	* src/base/ftoutln.c (FT_Outline_Decompose): Improve error tracing.

src/base/ftlcdfil.c

diff --git a/src/base/ftlcdfil.c b/src/base/ftlcdfil.c
index 5c38911..8d314df 100644
--- a/src/base/ftlcdfil.c
+++ b/src/base/ftlcdfil.c
@@ -77,7 +77,7 @@
 
 
     /* take care of bitmap flow */
-    if ( pitch > 0 )
+    if ( pitch > 0 && height > 0 )
       origin += pitch * (FT_Int)( height - 1 );
 
     /* horizontal in-place FIR filter */
@@ -192,7 +192,7 @@
 
 
     /* take care of bitmap flow */
-    if ( pitch > 0 )
+    if ( pitch > 0 && height > 0 )
       origin += pitch * (FT_Int)( height - 1 );
 
     /* horizontal in-place intra-pixel filter */