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[sfnt] Don't provide (completely) broken strike data. 

FreeType tries to sanitize strike header data; we now reject
completely broken ones.

* include/freetype/internal/tttypes.h (TT_FaceRec): New
`sbit_strike_map' array pointer.

* src/base/ftobjs.c (FT_Match_Size): Reject matches where either
width or height would be zero.
Add tracing message in case of error.

* src/sfnt/sfobjs.c (sfnt_load_face): Populate `sbit_strike_map',
only using (more or less) valid strike header data for
FT_Face's `available_sizes' array.
(sfnt_done_face): Updated.

* src/sfnt/ttsbit.c (tt_face_set_sbit_strike): Use
`sbit_strike_map'.
(tt_face_load_strike_metrics): Improve tracing.

* src/truetype/ttdriver.c (tt_size_select): Use `sbit_strike_map'.
This commit is contained in:
Werner Lemberg 2016-09-09 22:11:07 +02:00
parent d2d5968aed
commit d609b7c158
7 changed files with 74 additions and 14 deletions
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25
ChangeLog
View File

@ -1,3 +1,28 @@
2016-09-09 Werner Lemberg <wl@gnu.org>
[sfnt] Don't provide (completely) broken strike data.
FreeType tries to sanitize strike header data; we now reject
completely broken ones.
* include/freetype/internal/tttypes.h (TT_FaceRec): New
`sbit_strike_map' array pointer.
* src/base/ftobjs.c (FT_Match_Size): Reject matches where either
width or height would be zero.
Add tracing message in case of error.
* src/sfnt/sfobjs.c (sfnt_load_face): Populate `sbit_strike_map',
only using (more or less) valid strike header data for
FT_Face's `available_sizes' array.
(sfnt_done_face): Updated.
* src/sfnt/ttsbit.c (tt_face_set_sbit_strike): Use
`sbit_strike_map'.
(tt_face_load_strike_metrics): Improve tracing.
* src/truetype/ttdriver.c (tt_size_select): Use `sbit_strike_map'.
2016-09-08 Werner Lemberg <wl@gnu.org>
* Version 2.7 released.

4
include/freetype/freetype.h
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@ -951,6 +951,10 @@ FT_BEGIN_HEADER
/* strikes in the face. It is set to NULL if */
/* there is no bitmap strike. */
/* */
/* Note that FreeType tries to sanitize the */
/* strike data since they are sometimes sloppy */
/* or incorrect, but this can easily fail. */
/* */
/* num_charmaps :: The number of charmaps in the face. */
/* */
/* charmaps :: An array of the charmaps of the face. */

1
include/freetype/internal/tttypes.h
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@ -1371,6 +1371,7 @@ FT_BEGIN_HEADER
FT_ULong sbit_table_size;
TT_SbitTableType sbit_table_type;
FT_UInt sbit_num_strikes;
FT_UInt* sbit_strike_map;
FT_Byte* kern_table;
FT_ULong kern_table_size;

5
src/base/ftobjs.c
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@ -2631,6 +2631,9 @@
w = FT_PIX_ROUND( w );
h = FT_PIX_ROUND( h );
if ( !w || !h )
return FT_THROW( Invalid_Pixel_Size );
for ( i = 0; i < face->num_fixed_sizes; i++ )
{
FT_Bitmap_Size* bsize = face->available_sizes + i;
@ -2650,6 +2653,8 @@
}
}
FT_TRACE3(( "FT_Match_Size: no matching bitmap strike\n" ));
return FT_THROW( Invalid_Pixel_Size );
}

31
src/sfnt/sfobjs.c
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@ -1411,7 +1411,7 @@
* depths in the FT_Bitmap_Size record. This is a design error.
*/
{
FT_UInt i, count;
FT_UInt count;
count = face->sbit_num_strikes;
@ -1423,6 +1423,8 @@
FT_Short avgwidth = face->os2.xAvgCharWidth;
FT_Size_Metrics metrics;
FT_UInt strike_idx, bsize_idx;
if ( em_size == 0 || face->os2.version == 0xFFFFU )
{
@ -1430,31 +1432,43 @@
em_size = 1;
}
if ( FT_NEW_ARRAY( root->available_sizes, count ) )
/* to avoid invalid strike data in the `available_sizes' field */
/* of `FT_Face', we map `available_sizes' indices to strike */
/* indices */
if ( FT_NEW_ARRAY( root->available_sizes, count ) ||
FT_NEW_ARRAY( face->sbit_strike_map, count ) )
goto Exit;
for ( i = 0; i < count; i++ )
bsize_idx = 0;
for ( strike_idx = 0; strike_idx < count; strike_idx++ )
{
FT_Bitmap_Size* bsize = root->available_sizes + i;
FT_Bitmap_Size* bsize = root->available_sizes + bsize_idx;
error = sfnt->load_strike_metrics( face, i, &metrics );
error = sfnt->load_strike_metrics( face, strike_idx, &metrics );
if ( error )
goto Exit;
bsize->height = (FT_Short)( metrics.height >> 6 );
bsize->width = (FT_Short)(
( avgwidth * metrics.x_ppem + em_size / 2 ) / em_size );
bsize->width = (FT_Short)(
( avgwidth * metrics.x_ppem + em_size / 2 ) / em_size );
bsize->x_ppem = metrics.x_ppem << 6;
bsize->y_ppem = metrics.y_ppem << 6;
/* assume 72dpi */
bsize->size = metrics.y_ppem << 6;
/* only use strikes with valid PPEM values */
if ( bsize->x_ppem && bsize->y_ppem )
face->sbit_strike_map[bsize_idx++] = strike_idx;
}
/* reduce array size to the actually used elements */
(void)FT_RENEW_ARRAY( face->sbit_strike_map, count, bsize_idx );
root->face_flags |= FT_FACE_FLAG_FIXED_SIZES;
root->num_fixed_sizes = (FT_Int)count;
root->num_fixed_sizes = (FT_Int)bsize_idx;
}
}
@ -1648,6 +1662,7 @@
/* freeing sbit size table */
FT_FREE( face->root.available_sizes );
FT_FREE( face->sbit_strike_map );
face->root.num_fixed_sizes = 0;
FT_FREE( face->postscript_name );

12
src/sfnt/ttsbit.c
View File

@ -251,7 +251,14 @@
FT_Size_Request req,
FT_ULong* astrike_index )
{
return FT_Match_Size( (FT_Face)face, req, 0, astrike_index );
FT_Error error;
error = FT_Match_Size( (FT_Face)face, req, 0, astrike_index );
if ( !error )
*astrike_index = face->sbit_strike_map[*astrike_index];
return error;
}
@ -305,7 +312,8 @@
FT_TRACE2(( "tt_face_load_strike_metrics:"
" sanitizing invalid ascender and descender\n"
" "
" values for strike (%d, %d)\n",
" values for strike %d (%dppem, %dppem)\n",
strike_index,
metrics->x_ppem, metrics->y_ppem ));
/* sanitize buggy ascender and descender values */

10
src/truetype/ttdriver.c
View File

@ -273,25 +273,27 @@
static FT_Error
tt_size_select( FT_Size size,
FT_ULong strike_index )
FT_ULong bsize_index )
{
TT_Face ttface = (TT_Face)size->face;
TT_Size ttsize = (TT_Size)size;
FT_Error error = FT_Err_Ok;
FT_UInt strike_index = ttface->sbit_strike_map[bsize_index];
ttsize->strike_index = strike_index;
if ( FT_IS_SCALABLE( size->face ) )
{
/* use the scaled metrics, even when tt_size_reset fails */
FT_Select_Metrics( size->face, strike_index );
FT_Select_Metrics( size->face, bsize_index );
tt_size_reset( ttsize ); /* ignore return value */
}
else
{
SFNT_Service sfnt = (SFNT_Service) ttface->sfnt;
SFNT_Service sfnt = (SFNT_Service)ttface->sfnt;
FT_Size_Metrics* metrics = &size->metrics;
@ -319,7 +321,7 @@
if ( FT_HAS_FIXED_SIZES( size->face ) )
{
TT_Face ttface = (TT_Face)size->face;
SFNT_Service sfnt = (SFNT_Service) ttface->sfnt;
SFNT_Service sfnt = (SFNT_Service)ttface->sfnt;
FT_ULong strike_index;