Commit acd1879897cff476bb7e53c27d10f3e66b6f4b5c
2016-08-25T17:12:46
[sfnt] Speed up handling of invalid format 4 cmaps. * src/sfnt/ttcmap.c (tt_cmap4_next, tt_cmap4_char_map_binary): Add tests for `num_glyph' from `tt_cmap4_char_map_linear'.
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diff --git a/ChangeLog b/ChangeLog
index bde8b9d..0fc1a9d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2016-08-25 Werner Lemberg <wl@gnu.org>
+ [sfnt] Speed up handling of invalid format 4 cmaps.
+
+ * src/sfnt/ttcmap.c (tt_cmap4_next, tt_cmap4_char_map_binary): Add
+ tests for `num_glyph' from `tt_cmap4_char_map_linear'.
+
+2016-08-25 Werner Lemberg <wl@gnu.org>
+
* include/freetype/internal/ftdriver.h: Remove unused typedefs.
2016-08-22 Alexei Podtelezhnikov <apodtele@gmail.com>
diff --git a/src/sfnt/ttcmap.c b/src/sfnt/ttcmap.c
index 01255a8..0e0479d 100644
--- a/src/sfnt/ttcmap.c
+++ b/src/sfnt/ttcmap.c
@@ -763,6 +763,9 @@
static void
tt_cmap4_next( TT_CMap4 cmap )
{
+ TT_Face face = (TT_Face)cmap->cmap.cmap.charmap.face;
+ FT_Byte* limit = face->cmap_table + face->cmap_size;
+
FT_UInt charcode;
@@ -788,15 +791,19 @@
FT_Byte* p = values + 2 * ( charcode - cmap->cur_start );
+ /* if p > limit, the whole segment is invalid */
+ if ( p > limit )
+ goto Next_Segment;
+
do
{
FT_UInt gindex = FT_NEXT_USHORT( p );
- if ( gindex != 0 )
+ if ( gindex )
{
gindex = (FT_UInt)( (FT_Int)gindex + delta ) & 0xFFFFU;
- if ( gindex != 0 )
+ if ( gindex )
{
cmap->cur_charcode = charcode;
cmap->cur_gindex = gindex;
@@ -812,7 +819,26 @@
FT_UInt gindex = (FT_UInt)( (FT_Int)charcode + delta ) & 0xFFFFU;
- if ( gindex != 0 )
+ if ( gindex >= (FT_UInt)face->root.num_glyphs )
+ {
+ /* we have an invalid glyph index; if there is an overflow, */
+ /* we can adjust `charcode', otherwise the whole segment is */
+ /* invalid */
+ gindex = 0;
+
+ if ( (FT_Int)charcode + delta < 0 &&
+ (FT_Int)end + delta >= 0 )
+ charcode = (FT_UInt)( -delta );
+
+ else if ( (FT_Int)charcode + delta < 0x10000L &&
+ (FT_Int)end + delta >= 0x10000L )
+ charcode = (FT_UInt)( 0x10000L - delta );
+
+ else
+ goto Next_Segment;
+ }
+
+ if ( gindex )
{
cmap->cur_charcode = charcode;
cmap->cur_gindex = gindex;
@@ -822,6 +848,7 @@
}
}
+ Next_Segment:
/* we need to find another range */
if ( tt_cmap4_set_range( cmap, cmap->cur_range + 1 ) < 0 )
break;
@@ -1170,6 +1197,9 @@
FT_UInt32* pcharcode,
FT_Bool next )
{
+ TT_Face face = (TT_Face)cmap->cmap.charmap.face;
+ FT_Byte* limit = face->cmap_table + face->cmap_size;
+
FT_UInt num_segs2, start, end, offset;
FT_Int delta;
FT_UInt max, min, mid, num_segs;
@@ -1221,10 +1251,6 @@
if ( mid >= num_segs - 1 &&
start == 0xFFFFU && end == 0xFFFFU )
{
- TT_Face face = (TT_Face)cmap->cmap.charmap.face;
- FT_Byte* limit = face->cmap_table + face->cmap_size;
-
-
if ( offset && p + offset + 2 > limit )
{
delta = 1;
@@ -1347,13 +1373,43 @@
if ( offset )
{
p += offset + ( charcode - start ) * 2;
+
+ /* if p > limit, the whole segment is invalid */
+ if ( next && p > limit )
+ continue;
+
gindex = TT_PEEK_USHORT( p );
- if ( gindex != 0 )
+ if ( gindex )
+ {
gindex = (FT_UInt)( (FT_Int)gindex + delta ) & 0xFFFFU;
+ if ( gindex >= (FT_UInt)face->root.num_glyphs )
+ gindex = 0;
+ }
}
else
+ {
gindex = (FT_UInt)( (FT_Int)charcode + delta ) & 0xFFFFU;
+ if ( next && gindex >= (FT_UInt)face->root.num_glyphs )
+ {
+ /* we have an invalid glyph index; if there is an overflow, */
+ /* we can adjust `charcode', otherwise the whole segment is */
+ /* invalid */
+ gindex = 0;
+
+ if ( (FT_Int)charcode + delta < 0 &&
+ (FT_Int)end + delta >= 0 )
+ charcode = (FT_UInt)( -delta );
+
+ else if ( (FT_Int)charcode + delta < 0x10000L &&
+ (FT_Int)end + delta >= 0x10000L )
+ charcode = (FT_UInt)( 0x10000L - delta );
+
+ else
+ continue;
+ }
+ }
+
break;
}
}