[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.
This commit is contained in:
Werner Lemberg 2017-03-24 09:15:10 +01:00
parent 913f436d12
commit f958c48ee4
2 changed files with 24 additions and 0 deletions

View File

@ -1,3 +1,18 @@
2017-03-23 Werner Lemberg <wl@gnu.org>
[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 <wl@gnu.org>
[sfnt] Fix check for default named instance.

View File

@ -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;