Commit 2c2e6403b7c16cd1e3b20d18acdc935898eee040
2017-06-03T07:38:11
[bdf] Synchronize sanity checks with pcf driver. Reported as https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2054 https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2058 * src/bdf/bdfdrivr.c (BDF_Face_Init): Check font ascent and descent. Check AVERAGE_WIDTH, POINT_SIZE, PIXEL_SIZE, RESOLUTION_X, and RESOLUTION_Y properties.
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diff --git a/ChangeLog b/ChangeLog
index 83a239a..0bf03f3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,18 @@
2017-06-03 Werner Lemberg <wl@gnu.org>
+ [bdf] Synchronize sanity checks with pcf driver.
+
+ Reported as
+
+ https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2054
+ https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2058
+
+ * src/bdf/bdfdrivr.c (BDF_Face_Init): Check font ascent and descent.
+ Check AVERAGE_WIDTH, POINT_SIZE, PIXEL_SIZE, RESOLUTION_X, and
+ RESOLUTION_Y properties.
+
+2017-06-03 Werner Lemberg <wl@gnu.org>
+
[cff, truetype] Integer overflows.
Reported as
diff --git a/src/bdf/bdfdrivr.c b/src/bdf/bdfdrivr.c
index 540d367..c7b9b41 100644
--- a/src/bdf/bdfdrivr.c
+++ b/src/bdf/bdfdrivr.c
@@ -373,7 +373,7 @@ THE SOFTWARE.
/* we have a bdf font: let's construct the face object */
face->bdffont = font;
- /* BDF could not have multiple face in single font file.
+ /* BDF cannot have multiple faces in a single font file.
* XXX: non-zero face_index is already invalid argument, but
* Type1, Type42 driver has a convention to return
* an invalid argument error when the font could be
@@ -441,42 +441,130 @@ THE SOFTWARE.
FT_ZERO( bsize );
+ /* sanity checks */
+ if ( FT_ABS( font->font_ascent ) > 0x7FFF )
+ {
+ font->font_ascent = font->font_ascent < 0 ? -0x7FFF : 0x7FFF;
+ FT_TRACE0(( "BDF_Face_Init: clamping font ascent to value %d\n",
+ font->font_ascent ));
+ }
+ if ( FT_ABS( font->font_descent ) > 0x7FFF )
+ {
+ font->font_descent = font->font_descent < 0 ? -0x7FFF : 0x7FFF;
+ FT_TRACE0(( "BDF_Face_Init: clamping font descent to value %d\n",
+ font->font_descent ));
+ }
+
bsize->height = (FT_Short)( font->font_ascent + font->font_descent );
prop = bdf_get_font_property( font, "AVERAGE_WIDTH" );
if ( prop )
- bsize->width = (FT_Short)( ( prop->value.l + 5 ) / 10 );
+ {
+#ifdef FT_DEBUG_LEVEL_TRACE
+ if ( prop->value.l < 0 )
+ FT_TRACE0(( "BDF_Face_Init: negative average width\n" ));
+#endif
+ if ( ( FT_ABS( prop->value.l ) > 0x7FFFL * 10 - 5 ) )
+ {
+ bsize->width = 0x7FFF;
+ FT_TRACE0(( "BDF_Face_Init: clamping average width to value %d\n",
+ bsize->width ));
+ }
+ else
+ bsize->width = FT_ABS( (FT_Short)( ( prop->value.l + 5 ) / 10 ) );
+ }
else
- bsize->width = (FT_Short)( bsize->height * 2/3 );
+ {
+ /* this is a heuristical value */
+ bsize->width = (FT_Short)FT_MulDiv( bsize->height, 2, 3 );
+ }
prop = bdf_get_font_property( font, "POINT_SIZE" );
if ( prop )
+ {
+#ifdef FT_DEBUG_LEVEL_TRACE
+ if ( prop->value.l < 0 )
+ FT_TRACE0(( "BDF_Face_Init: negative point size\n" ));
+#endif
/* convert from 722.7 decipoints to 72 points per inch */
- bsize->size =
- (FT_Pos)( ( prop->value.l * 64 * 7200 + 36135L ) / 72270L );
+ if ( FT_ABS( prop->value.l ) > 0x504C2L ) /* 0x7FFF * 72270/7200 */
+ {
+ bsize->size = 0x7FFF;
+ FT_TRACE0(( "BDF_Face_Init: clamping point size to value %d\n",
+ bsize->size ));
+ }
+ else
+ bsize->size = FT_MulDiv( FT_ABS( prop->value.l ),
+ 64 * 7200,
+ 72270L );
+ }
else
+ {
+ /* this is a heuristical value */
bsize->size = bsize->width * 64;
+ }
prop = bdf_get_font_property( font, "PIXEL_SIZE" );
if ( prop )
- bsize->y_ppem = (FT_Short)prop->value.l * 64;
+ {
+#ifdef FT_DEBUG_LEVEL_TRACE
+ if ( prop->value.l < 0 )
+ FT_TRACE0(( "BDF_Face_Init: negative pixel size\n" ));
+#endif
+ if ( FT_ABS( prop->value.l ) > 0x7FFF )
+ {
+ bsize->y_ppem = 0x7FFF << 6;
+ FT_TRACE0(( "BDF_Face_Init: clamping pixel size to value %d\n",
+ bsize->y_ppem ));
+ }
+ else
+ bsize->y_ppem = FT_ABS( (FT_Short)prop->value.l ) << 6;
+ }
prop = bdf_get_font_property( font, "RESOLUTION_X" );
if ( prop )
- resolution_x = (FT_Short)prop->value.l;
+ {
+#ifdef FT_DEBUG_LEVEL_TRACE
+ if ( prop->value.l < 0 )
+ FT_TRACE0(( "BDF_Face_Init: negative X resolution\n" ));
+#endif
+ if ( FT_ABS( prop->value.l ) > 0x7FFF )
+ {
+ resolution_x = 0x7FFF;
+ FT_TRACE0(( "BDF_Face_Init: clamping X resolution to value %d\n",
+ resolution_x ));
+ }
+ else
+ resolution_x = FT_ABS( (FT_Short)prop->value.l );
+ }
prop = bdf_get_font_property( font, "RESOLUTION_Y" );
if ( prop )
- resolution_y = (FT_Short)prop->value.l;
+ {
+#ifdef FT_DEBUG_LEVEL_TRACE
+ if ( prop->value.l < 0 )
+ FT_TRACE0(( "BDF_Face_Init: negative Y resolution\n" ));
+#endif
+ if ( FT_ABS( prop->value.l ) > 0x7FFF )
+ {
+ resolution_y = 0x7FFF;
+ FT_TRACE0(( "BDF_Face_Init: clamping Y resolution to value %d\n",
+ resolution_y ));
+ }
+ else
+ resolution_y = FT_ABS( (FT_Short)prop->value.l );
+ }
if ( bsize->y_ppem == 0 )
{
bsize->y_ppem = bsize->size;
if ( resolution_y )
- bsize->y_ppem = bsize->y_ppem * resolution_y / 72;
+ bsize->y_ppem = FT_MulDiv( bsize->y_ppem, resolution_y, 72 );
}
if ( resolution_x && resolution_y )
- bsize->x_ppem = bsize->y_ppem * resolution_x / resolution_y;
+ bsize->x_ppem = FT_MulDiv( bsize->y_ppem,
+ resolution_x,
+ resolution_y );
else
bsize->x_ppem = bsize->y_ppem;
}