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[pcf] Limit bitmap allocation and loading.

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Loading huge bitmaps now requires selecting huge size, fixes #1411.

* src/pcf/pcfread.c (pcf_get_metrics): Remove/delay sanity checks.
* src/pcf/pcfdrivr.c (PCF_Glyph_Load): Sanitize bitmap dimensions.
This commit is contained in:
Alexei Podtelezhnikov 2026-04-12 12:00:47 -04:00
parent 3221895b3f
commit ca53609f3c
2 changed files with 20 additions and 29 deletions
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33
src/pcf/pcfdrivr.c
View file

@ -458,6 +458,7 @@ THE SOFTWARE.
PCF_Face face = (PCF_Face)size->face;
FT_Stream stream;
FT_Error error = FT_Err_Ok;
FT_Int width, height;
FT_Bitmap* bitmap = &slot->bitmap;
PCF_Metric metric;
FT_ULong bytes;
@ -481,29 +482,36 @@ THE SOFTWARE.
metric = face->metrics + glyph_index;
bitmap->rows = (unsigned int)( metric->ascent +
metric->descent );
bitmap->width = (unsigned int)( metric->rightSideBearing -
metric->leftSideBearing );
height = metric->ascent + metric->descent;
width = metric->rightSideBearing - metric->leftSideBearing;
/* sanity checks against reasonable size */
if ( height < 0 || height > 4 * size->metrics.y_ppem )
height = 0;
if ( width < 0 || width > 4 * size->metrics.x_ppem )
width = 0;
bitmap->rows = (unsigned int)height;
bitmap->width = (unsigned int)width;
bitmap->num_grays = 1;
bitmap->pixel_mode = FT_PIXEL_MODE_MONO;
switch ( PCF_GLYPH_PAD( face->bitmapsFormat ) )
{
case 1:
bitmap->pitch = (int)( ( bitmap->width + 7 ) >> 3 );
bitmap->pitch = ( width + 7 ) >> 3;
break;
case 2:
bitmap->pitch = (int)( ( ( bitmap->width + 15 ) >> 4 ) << 1 );
bitmap->pitch = ( ( width + 15 ) >> 4 ) << 1;
break;
case 4:
bitmap->pitch = (int)( ( ( bitmap->width + 31 ) >> 5 ) << 2 );
bitmap->pitch = ( ( width + 31 ) >> 5 ) << 2;
break;
case 8:
bitmap->pitch = (int)( ( ( bitmap->width + 63 ) >> 6 ) << 3 );
bitmap->pitch = ( ( width + 63 ) >> 6 ) << 3;
break;
default:
@ -517,9 +525,8 @@ THE SOFTWARE.
slot->metrics.horiAdvance = (FT_Pos)( metric->characterWidth * 64 );
slot->metrics.horiBearingX = (FT_Pos)( metric->leftSideBearing * 64 );
slot->metrics.horiBearingY = (FT_Pos)( metric->ascent * 64 );
slot->metrics.width = (FT_Pos)( ( metric->rightSideBearing -
metric->leftSideBearing ) * 64 );
slot->metrics.height = (FT_Pos)( bitmap->rows * 64 );
slot->metrics.width = (FT_Pos)( width * 64 );
slot->metrics.height = (FT_Pos)( height * 64 );
ft_synthesize_vertical_metrics( &slot->metrics,
( face->accel.fontAscent +
@ -529,12 +536,12 @@ THE SOFTWARE.
goto Exit;
/* XXX: to do: are there cases that need repadding the bitmap? */
bytes = (FT_ULong)bitmap->pitch * bitmap->rows;
error = ft_glyphslot_alloc_bitmap( slot );
if ( error )
goto Exit;
bytes = (FT_ULong)bitmap->pitch * bitmap->rows;
if ( FT_STREAM_SEEK( metric->bits ) ||
FT_STREAM_READ( bitmap->buffer, bytes ) )
goto Exit;

16
src/pcf/pcfread.c
View file

@ -783,22 +783,6 @@ THE SOFTWARE.
if ( error )
break;
/* sanity checks -- those values are used in `PCF_Glyph_Load' to */
/* compute a glyph's bitmap dimensions, thus setting them to zero in */
/* case of an error disables this particular glyph only */
if ( metrics->rightSideBearing < metrics->leftSideBearing ||
metrics->ascent < -metrics->descent )
{
metrics->characterWidth = 0;
metrics->leftSideBearing = 0;
metrics->rightSideBearing = 0;
metrics->ascent = 0;
metrics->descent = 0;
FT_TRACE0(( "pcf_get_metrics:"
" invalid metrics for glyph %lu\n", i ));
}
}
if ( error )