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[sfnt] Improve extraction of number of named instances. 

* src/sfnt/sfobjs.c (sfnt_init_face)
[TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Check number of instances against
`fvar' table size.
This commit is contained in:
Werner Lemberg 2015-10-11 07:55:25 +02:00
parent a724dcf5c3
commit 4f7f6f6e47
2 changed files with 43 additions and 4 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
2015-10-11 Werner Lemberg <wl@gnu.org>
[sfnt] Improve extraction of number of named instances.
* src/sfnt/sfobjs.c (sfnt_init_face)
[TT_CONFIG_OPTION_GX_VAR_SUPPORT]: Check number of instances against
`fvar' table size.
2015-10-10 Alexei Podtelezhnikov <apodtele@gmail.com>
* src/base/ftoutln.c (FT_Outline_Get_Orientation): Fix overflow

39
src/sfnt/sfobjs.c
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@ -883,9 +883,17 @@
#ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
{
FT_ULong fvar_len;
FT_ULong fvar_len;
FT_ULong version;
FT_ULong offset;
FT_UShort num_axes;
FT_UShort axis_size;
FT_UShort num_instances;
FT_Int instance_index;
FT_UShort instance_size;
FT_Int instance_index;
instance_index = FT_ABS( face_instance_index ) >> 16;
@ -893,8 +901,31 @@
/* test whether current face is a GX font with named instances */
if ( face->goto_table( face, TTAG_fvar, stream, &fvar_len ) ||
fvar_len < 20 ||
FT_STREAM_SKIP( 12 ) ||
FT_READ_USHORT( num_instances ) )
FT_READ_ULONG( version ) ||
FT_READ_USHORT( offset ) ||
FT_STREAM_SKIP( 2 ) ||
FT_READ_USHORT( num_axes ) ||
FT_READ_USHORT( axis_size ) ||
FT_READ_USHORT( num_instances ) ||
FT_READ_USHORT( instance_size ) )
{
version = 0;
num_axes = 0;
axis_size = 0;
num_instances = 0;
instance_size = 0;
}
/* check that the data is bound by the table length; */
/* based on similar code in function `TT_Get_MM_Var' */
if ( version != 0x00010000UL ||
axis_size != 20 ||
num_axes > 0x3FFE ||
instance_size != 4 + 4 * num_axes ||
num_instances > 0x7EFF ||
offset +
axis_size * num_axes +
instance_size * num_instances > fvar_len )
num_instances = 0;
/* we support at most 2^15 - 1 instances */