[sfnt] Additional bounds checks for COLR v1 table handling.

* src/sfnt/ttcolr.c (read_paint): Add `colr` argument, necessary for...
... another use of `ENSURE_READ_BYTES`.
Update callers.
(tt_face_get_paint_layers): Ensure that the 4-byte paint table
offset can be read.

This is a follow-up to !124 and issue
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=52404
This commit is contained in:
Dominik Röttsches 2022-10-18 14:45:43 +03:00 committed by Werner Lemberg
parent af46fcc15a
commit 0b62c1e43d

View File

@ -516,7 +516,8 @@
static FT_Bool
read_color_line( FT_Byte* color_line_p,
read_color_line( Colr* colr,
FT_Byte* color_line_p,
FT_ColorLine* colorline,
FT_Bool read_variable )
{
@ -524,6 +525,8 @@
FT_PaintExtend paint_extend;
ENSURE_READ_BYTES( 3 );
paint_extend = (FT_PaintExtend)FT_NEXT_BYTE( p );
if ( paint_extend > FT_COLR_PAINT_EXTEND_REFLECT )
return 0;
@ -748,7 +751,8 @@
( (FT_PaintFormat_Internal)apaint->format ==
FT_COLR_PAINTFORMAT_INTERNAL_VAR_LINEAR_GRADIENT ) ) )
{
if ( !read_color_line( child_table_p,
if ( !read_color_line( colr,
child_table_p,
&apaint->u.linear_gradient.colorline,
do_read_var ) )
return 0;
@ -798,7 +802,8 @@
FT_Pos tmp;
if ( !read_color_line( child_table_p,
if ( !read_color_line( colr,
child_table_p,
&apaint->u.radial_gradient.colorline,
do_read_var ) )
return 0;
@ -856,7 +861,8 @@
( (FT_PaintFormat_Internal)apaint->format ==
FT_COLR_PAINTFORMAT_INTERNAL_VAR_SWEEP_GRADIENT ) ) )
{
if ( !read_color_line( child_table_p,
if ( !read_color_line( colr,
child_table_p,
&apaint->u.sweep_gradient.colorline,
do_read_var) )
return 0;
@ -1558,13 +1564,6 @@
*/
p = iterator->p;
/*
* First ensure that p is within COLRv1.
*/
if ( p < colr->layers_v1 ||
p >= ( (FT_Byte*)colr->table + colr->table_size ) )
return 0;
/*
* Do a cursor sanity check of the iterator. Counting backwards from
* where it stands, we need to end up at a position after the beginning
@ -1581,6 +1580,14 @@
colr->num_layers_v1 * LAYER_V1_LIST_PAINT_OFFSET_SIZE ) )
return 0;
/*
* Before reading, ensure that `p` is within 'COLR' v1 and we can read a
* 4-byte ULONG.
*/
if ( p < colr->layers_v1 ||
p > ( (FT_Byte*)colr->table + colr->table_size - 4 ) )
return 0;
paint_offset =
FT_NEXT_ULONG( p );
opaque_paint->insert_root_transform =