Commit 74af85c4b62b35e55b0ce9dec55ee10cbc4962a2
2014-12-08T16:01:50
[pcf] Fix Savannah bug #43774. Work around `features' of X11's `pcfWriteFont' and `pcfReadFont' functions. Since the PCF format doesn't have an official specification, we have to exactly follow these functions' behaviour. The problem was unveiled with a patch from 2014-11-06, fixing issue #43547. * src/pcf/pcfread.c (pcf_read_TOC): Don't check table size for last element. Instead, assign real size.
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diff --git a/ChangeLog b/ChangeLog
index afc342f..e560b4f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2014-12-08 Werner Lemberg <wl@gnu.org>
+
+ [pcf] Fix Savannah bug #43774.
+
+ Work around `features' of X11's `pcfWriteFont' and `pcfReadFont'
+ functions. Since the PCF format doesn't have an official
+ specification, we have to exactly follow these functions' behaviour.
+
+ The problem was unveiled with a patch from 2014-11-06, fixing issue
+ #43547.
+
+ * src/pcf/pcfread.c (pcf_read_TOC): Don't check table size for last
+ element. Instead, assign real size.
+
2014-12-07 Werner Lemberg <wl@gnu.org>
Work around a bug in Borland's C++ compiler.
diff --git a/src/pcf/pcfread.c b/src/pcf/pcfread.c
index 998cbed..e3caf82 100644
--- a/src/pcf/pcfread.c
+++ b/src/pcf/pcfread.c
@@ -2,7 +2,7 @@
FreeType font driver for pcf fonts
- Copyright 2000-2010, 2012, 2013 by
+ Copyright 2000-2010, 2012-2014 by
Francesco Zappa Nardelli
Permission is hereby granted, free of charge, to any person obtaining a copy
@@ -78,7 +78,7 @@ THE SOFTWARE.
FT_FRAME_START( 16 ),
FT_FRAME_ULONG_LE( type ),
FT_FRAME_ULONG_LE( format ),
- FT_FRAME_ULONG_LE( size ),
+ FT_FRAME_ULONG_LE( size ), /* rounded up to a multiple of 4 */
FT_FRAME_ULONG_LE( offset ),
FT_FRAME_END
};
@@ -95,9 +95,11 @@ THE SOFTWARE.
FT_Memory memory = FT_FACE( face )->memory;
FT_UInt n;
+ FT_ULong size;
- if ( FT_STREAM_SEEK ( 0 ) ||
- FT_STREAM_READ_FIELDS ( pcf_toc_header, toc ) )
+
+ if ( FT_STREAM_SEEK( 0 ) ||
+ FT_STREAM_READ_FIELDS( pcf_toc_header, toc ) )
return FT_THROW( Cannot_Open_Resource );
if ( toc->version != PCF_FILE_VERSION ||
@@ -154,14 +156,35 @@ THE SOFTWARE.
break;
}
- /* we now check whether the `size' and `offset' values are reasonable: */
- /* `offset' + `size' must not exceed the stream size */
+ /*
+ * We now check whether the `size' and `offset' values are reasonable:
+ * `offset' + `size' must not exceed the stream size.
+ *
+ * Note, however, that X11's `pcfWriteFont' routine (used by the
+ * `bdftopcf' program to create PDF font files) has two special
+ * features.
+ *
+ * - It always assigns the accelerator table a size of 100 bytes in the
+ * TOC, regardless of its real size, which can vary between 34 and 72
+ * bytes.
+ *
+ * - Due to the way the routine is designed, it ships out the last font
+ * table with its real size, ignoring the TOC's size value. Since
+ * the TOC size values are always rounded up to a multiple of 4, the
+ * difference can be up to three bytes for all tables except the
+ * accelerator table, for which the difference can be as large as 66
+ * bytes.
+ *
+ */
+
tables = face->toc.tables;
- for ( n = 0; n < toc->count; n++ )
+ size = stream->size;
+
+ for ( n = 0; n < toc->count - 1; n++ )
{
/* we need two checks to avoid overflow */
- if ( ( tables->size > stream->size ) ||
- ( tables->offset > stream->size - tables->size ) )
+ if ( ( tables->size > size ) ||
+ ( tables->offset > size - tables->size ) )
{
error = FT_THROW( Invalid_Table );
goto Exit;
@@ -169,6 +192,15 @@ THE SOFTWARE.
tables++;
}
+ /* no check of `tables->size' for last table element ... */
+ if ( ( tables->offset > size ) )
+ {
+ error = FT_THROW( Invalid_Table );
+ goto Exit;
+ }
+ /* ... instead, we adjust `tables->size' to the real value */
+ tables->size = size - tables->offset;
+
#ifdef FT_DEBUG_LEVEL_TRACE
{
@@ -733,8 +765,8 @@ THE SOFTWARE.
FT_TRACE4(( " number of bitmaps: %d\n", nbitmaps ));
- /* XXX: PCF_Face->nmetrics is singed FT_Long, see pcf.h */
- if ( face->nmetrics < 0 || nbitmaps != ( FT_ULong )face->nmetrics )
+ /* XXX: PCF_Face->nmetrics is signed FT_Long, see pcf.h */
+ if ( face->nmetrics < 0 || nbitmaps != (FT_ULong)face->nmetrics )
return FT_THROW( Invalid_File_Format );
if ( FT_NEW_ARRAY( offsets, nbitmaps ) )