Commit f312b3402a5ddece433a0a0d24070b7c262df218
2023-04-22T02:11:21
[t1cid] Change the trace messages of the charstrings retrieval errors. The t1cid driver catches 3 types of errors in the charstrings retrieval; A) The invalid FD number, there are 2 subtypes; A-1) FD number is the maximum number fitting to FDBytes. A-2) FD number is greater than num_dicts. B) Declared length is overrunning. C) Declared length is invalid (its end is before its head). Considering that some widely distributed fonts (e.g., "CJKV" book by O'Reilly) have A-1 errors in the unimplemented glyphs, the trace level for A-1 is calmed to level 1. The errors A-2, B, and C would be irregular; their trace levels are kept at level 0, but the updated trace messages include the CID number.
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diff --git a/src/cid/cidgload.c b/src/cid/cidgload.c
index ba4b756..66e2983 100644
--- a/src/cid/cidgload.c
+++ b/src/cid/cidgload.c
@@ -117,11 +117,44 @@
off2 = cid_get_offset( &p, cid->gd_bytes );
FT_FRAME_EXIT();
- if ( fd_select >= cid->num_dicts ||
- off2 > stream->size ||
- off1 > off2 )
+
+ if ( fd_select >= cid->num_dicts )
{
- FT_TRACE0(( "cid_load_glyph: invalid glyph stream offsets\n" ));
+ /*
+ * fd_select == 0xFF is often used to indicate that the CID
+ * has no charstring to be rendered, similar to GID = 0xFFFF
+ * in TrueType fonts.
+ */
+ if ( (cid->fd_bytes == 1 && fd_select == 0xFFU ) ||
+ (cid->fd_bytes == 2 && fd_select == 0xFFFFU ) )
+ {
+ FT_TRACE1(( "cid_load_glyph: fail for glyph_index=%d, "
+ "FD number %d is the max integer fitting into %d byte%s\n",
+ glyph_index, fd_select, cid->fd_bytes,
+ cid->fd_bytes == 1 ? "" : "s" ));
+ }
+ else
+ {
+ FT_TRACE0(( "cid_load_glyph: fail for glyph_index=%d, "
+ "FD number %d > number of dicts %d\n",
+ glyph_index, fd_select, cid->num_dicts ));
+ }
+ error = FT_THROW( Invalid_Offset );
+ goto Exit;
+ }
+ else if ( off2 > stream->size )
+ {
+ FT_TRACE0(( "cid_load_glyph: fail for glyph_index=%d, "
+ "end of the glyph data is beyond the data stream\n",
+ glyph_index ));
+ error = FT_THROW( Invalid_Offset );
+ goto Exit;
+ }
+ else if ( off1 > off2 )
+ {
+ FT_TRACE0(( "cid_load_glyph: fail for glyph_index=%d, "
+ "the end position of glyph data is set before the start position\n",
+ glyph_index ));
error = FT_THROW( Invalid_Offset );
goto Exit;
}
@@ -161,7 +194,9 @@
cs_offset = decoder->lenIV >= 0 ? (FT_UInt)decoder->lenIV : 0;
if ( cs_offset > glyph_length )
{
- FT_TRACE0(( "cid_load_glyph: invalid glyph stream offsets\n" ));
+ FT_TRACE0(( "cid_load_glyph: fail for glyph_index=%d, "
+ "offset to the charstring is beyond glyph length\n",
+ glyph_index ));
error = FT_THROW( Invalid_Offset );
goto Exit;
}