ref: f958c48ee431bef8d4d466b40c9cb2d4dbcb7791
parent: 913f436d12dfe682c349eff8bf4cdd9065ff117d
author: Werner Lemberg <[email protected]>
date: Fri Mar 24 05:15:10 EDT 2017
[psaux] Better protect `flex' handling. Reported as https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=935 * src/psaux/t1decode.c (t1_decoder_parse_charstrings) <callothersubr>: Since there is not a single flex operator but a series of subroutine calls, malformed fonts can call arbitrary other operators after the start of a flex, possibly adding points. For this reason we have to check the available number of points before inserting a point.
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,20 @@
2017-03-23 Werner Lemberg <[email protected]>
+ [psaux] Better protect `flex' handling.
+
+ Reported as
+
+ https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=935
+
+ * src/psaux/t1decode.c (t1_decoder_parse_charstrings)
+ <callothersubr>: Since there is not a single flex operator but a
+ series of subroutine calls, malformed fonts can call arbitrary other
+ operators after the start of a flex, possibly adding points. For
+ this reason we have to check the available number of points before
+ inserting a point.
+
+2017-03-23 Werner Lemberg <[email protected]>
+
[sfnt] Fix check for default named instance.
* src/sfnt/sfobjs.c (sfnt_init_face): A `fixed' number needs four
--- a/src/psaux/t1decode.c
+++ b/src/psaux/t1decode.c
@@ -780,10 +780,19 @@
/* point without adding any point to the outline */
idx = decoder->num_flex_vectors++;
if ( idx > 0 && idx < 7 )
+ {+ /* in malformed fonts it is possible to have other */
+ /* opcodes in the middle of a flex (which don't */
+ /* increase `num_flex_vectors'); we thus have to */
+ /* check whether we can add a point */
+ if ( FT_SET_ERROR( t1_builder_check_points( builder, 1 ) ) )
+ goto Syntax_Error;
+
t1_builder_add_point( builder,
x,
y,
(FT_Byte)( idx == 3 || idx == 6 ) );
+ }
}
break;