Commit 8f633a08f1b7e5f64d2afd3805f6fb491f8c7086
2016-12-18T06:42:31
[cff] Better handling of non-CFF font formats. * src/cff/cffload.c (cff_font_load): Pure CFFs don't have a signature, so return `FT_Err_Unknown_File_Format' more often.
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diff --git a/ChangeLog b/ChangeLog
index 7b994d2..7011d05 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-12-18 Werner Lemberg <wl@gnu.org>
+
+ [cff] Better handling of non-CFF font formats.
+
+ * src/cff/cffload.c (cff_font_load): Pure CFFs don't have a
+ signature, so return `FT_Err_Unknown_File_Format' more often.
+
2016-12-17 Werner Lemberg <wl@gnu.org>
* src/cff/cffload.c (cff_build_blend_vector): Remove redundant code.
diff --git a/src/cff/cffload.c b/src/cff/cffload.c
index f8cac42..d347b0a 100644
--- a/src/cff/cffload.c
+++ b/src/cff/cffload.c
@@ -2111,8 +2111,15 @@
}
else
{
+ FT_Byte absolute_offset;
+
+
+ if ( FT_READ_BYTE( absolute_offset ) )
+ goto Exit;
+
if ( font->version_major != 1 ||
- font->header_size < 4 )
+ font->header_size < 4 ||
+ absolute_offset > 4 )
{
FT_TRACE2(( " not a CFF font header\n" ));
error = FT_THROW( Unknown_File_Format );
@@ -2122,7 +2129,17 @@
/* skip the rest of the header */
if ( FT_STREAM_SEEK( base_offset + font->header_size ) )
+ {
+ /* For pure CFFs we have read only four bytes so far. Contrary to */
+ /* other formats like SFNT those bytes doesn't define a signature; */
+ /* it is thus possible that the font isn't a CFF at all. */
+ if ( pure_cff )
+ {
+ FT_TRACE2(( " not a CFF file\n" ));
+ error = FT_THROW( Unknown_File_Format );
+ }
goto Exit;
+ }
if ( cff2 )
{
@@ -2150,8 +2167,17 @@
{
/* for CFF, read the name, top dict, string and global subrs index */
if ( FT_SET_ERROR( cff_index_init( &font->name_index,
- stream, 0, cff2 ) ) ||
- FT_SET_ERROR( cff_index_init( &font->font_dict_index,
+ stream, 0, cff2 ) ) )
+ {
+ if ( pure_cff )
+ {
+ FT_TRACE2(( " not a CFF file\n" ));
+ error = FT_THROW( Unknown_File_Format );
+ }
+ goto Exit;
+ }
+
+ if ( FT_SET_ERROR( cff_index_init( &font->font_dict_index,
stream, 0, cff2 ) ) ||
FT_SET_ERROR( cff_index_init( &string_index,
stream, 1, cff2 ) ) ||