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Disallow null-enabled offsets to unsized structures...

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...like UnsizedArrayOf<>.

This fixes a class of crasher bugs, mostly with color and AAT tables.  We
cannot use nullable offsets to varsized data that does not declare min_size,
because it's nost safe to use our fixed-size null pool for types that have
their size external.  So, use non_null'able offsets for these.

A further enhancement would be to make use of min_size in Null<> itself.
Will try that after.
This commit is contained in:
Behdad Esfahbod 2018-09-15 19:43:33 +02:00
parent 9ff76c6025
commit 10642b3fbf
12 changed files with 38 additions and 33 deletions
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8
src/hb-aat-layout-common.hh
View File

@ -243,7 +243,7 @@ struct LookupSegmentArray
GlyphID last; /* Last GlyphID in this segment */
GlyphID first; /* First GlyphID in this segment */
OffsetTo<UnsizedArrayOf<T> >
OffsetTo<UnsizedArrayOf<T>, HBUINT16, false>
valuesZ; /* A 16-bit offset from the start of
* the table to the data. */
public:
@ -522,11 +522,11 @@ struct StateTable
protected:
HBUINT32 nClasses; /* Number of classes, which is the number of indices
* in a single line in the state array. */
LOffsetTo<Lookup<HBUINT16> >
LOffsetTo<Lookup<HBUINT16>, false>
classTable; /* Offset to the class table. */
LOffsetTo<UnsizedArrayOf<HBUINT16> >
LOffsetTo<UnsizedArrayOf<HBUINT16>, false>
stateArrayTable;/* Offset to the state array. */
LOffsetTo<UnsizedArrayOf<Entry<Extra> > >
LOffsetTo<UnsizedArrayOf<Entry<Extra> >, false>
entryTable; /* Offset to the entry array. */
public:

2
src/hb-aat-layout-feat-table.hh
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@ -78,7 +78,7 @@ struct FeatureName
protected:
HBUINT16 feature; /* Feature type. */
HBUINT16 nSettings; /* The number of records in the setting name array. */
LOffsetTo<UnsizedArrayOf<SettingName> >
LOffsetTo<UnsizedArrayOf<SettingName>, false>
settingTable; /* Offset in bytes from the beginning of this table to
* this feature's setting name array. The actual type of
* record this offset refers to will depend on the

10
src/hb-aat-layout-morx-table.hh
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@ -311,7 +311,7 @@ struct ContextualSubtable
protected:
StateTable<EntryData>
machine;
LOffsetTo<UnsizedOffsetListOf<Lookup<GlyphID>, HBUINT32> >
LOffsetTo<UnsizedOffsetListOf<Lookup<GlyphID>, HBUINT32>, false>
substitutionTables;
public:
DEFINE_SIZE_STATIC (20);
@ -473,11 +473,11 @@ struct LigatureSubtable
protected:
StateTable<EntryData>
machine;
LOffsetTo<UnsizedArrayOf<HBUINT32> >
LOffsetTo<UnsizedArrayOf<HBUINT32>, false>
ligAction; /* Offset to the ligature action table. */
LOffsetTo<UnsizedArrayOf<HBUINT16> >
LOffsetTo<UnsizedArrayOf<HBUINT16>, false>
component; /* Offset to the component table. */
LOffsetTo<UnsizedArrayOf<GlyphID> >
LOffsetTo<UnsizedArrayOf<GlyphID>, false>
ligature; /* Offset to the actual ligature lists. */
public:
DEFINE_SIZE_STATIC (28);
@ -715,7 +715,7 @@ struct InsertionSubtable
protected:
StateTable<EntryData>
machine;
LOffsetTo<UnsizedArrayOf<GlyphID> >
LOffsetTo<UnsizedArrayOf<GlyphID>, false>
insertionAction; /* Byte offset from stateHeader to the start of
* the insertion glyph table. */
public:

4
src/hb-aat-layout-trak-table.hh
View File

@ -68,7 +68,7 @@ struct TrackTableEntry
protected:
Fixed track; /* Track value for this record. */
NameID trackNameID; /* The 'name' table index for this track */
OffsetTo<UnsizedArrayOf<FWORD> >
OffsetTo<UnsizedArrayOf<FWORD>, HBUINT16, false>
valuesZ; /* Offset from start of tracking table to
* per-size tracking values for this track. */
@ -134,7 +134,7 @@ struct TrackData
protected:
HBUINT16 nTracks; /* Number of separate tracks included in this table. */
HBUINT16 nSizes; /* Number of point sizes included in this table. */
LOffsetTo<UnsizedArrayOf<Fixed> >
LOffsetTo<UnsizedArrayOf<Fixed>, false>
sizeTable; /* Offset to array[nSizes] of size values. */
UnsizedArrayOf<TrackTableEntry>
trackTable; /* Array[nTracks] of TrackTableEntry records. */

2
src/hb-aat-ltag-table.hh
View File

@ -46,7 +46,7 @@ struct FTStringRange
}
protected:
OffsetTo<UnsizedArrayOf<HBUINT8> >
OffsetTo<UnsizedArrayOf<HBUINT8>, HBUINT16, false>
tag; /* Offset from the start of the table to
* the beginning of the string */
HBUINT16 length; /* String length (in bytes) */

5
src/hb-open-type.hh
View File

@ -226,9 +226,14 @@ struct FixedVersion
* Use: (base+offset)
*/
template <typename Type, bool has_null_> struct assert_has_min_size { static_assert (Type::min_size > 0); };
template <typename Type> struct assert_has_min_size<Type, false> {};
template <typename Type, typename OffsetType=HBUINT16, bool has_null=true>
struct OffsetTo : Offset<OffsetType, has_null>
{
static_assert (sizeof (assert_has_min_size<Type, has_null>) || true);
inline const Type& operator () (const void *base) const
{
if (unlikely (this->is_null ())) return Null(Type);

4
src/hb-ot-color-cbdt-table.hh
View File

@ -264,8 +264,6 @@ struct IndexSubtableArray
protected:
UnsizedArrayOf<IndexSubtableRecord> indexSubtablesZ;
public:
DEFINE_SIZE_ARRAY(0, indexSubtablesZ);
};
struct BitmapSizeTable
@ -289,7 +287,7 @@ struct BitmapSizeTable
}
protected:
LOffsetTo<IndexSubtableArray>
LOffsetTo<IndexSubtableArray, false>
indexSubtableArrayOffset;
HBUINT32 indexTablesSize;
HBUINT32 numberOfIndexSubtables;

4
src/hb-ot-color-colr-table.hh
View File

@ -129,9 +129,9 @@ struct COLR
protected:
HBUINT16 version; /* Table version number */
HBUINT16 numBaseGlyphs; /* Number of Base Glyph Records */
LOffsetTo<UnsizedArrayOf<BaseGlyphRecord> >
LOffsetTo<UnsizedArrayOf<BaseGlyphRecord>, false>
baseGlyphsZ; /* Offset to Base Glyph records. */
LOffsetTo<UnsizedArrayOf<LayerRecord> >
LOffsetTo<UnsizedArrayOf<LayerRecord>, false>
layersZ; /* Offset to Layer Records */
HBUINT16 numLayers; /* Number of Layer Records */
public:

8
src/hb-ot-color-cpal-table.hh
View File

@ -118,15 +118,15 @@ struct CPALV1Tail
}
protected:
LOffsetTo<UnsizedArrayOf<HBUINT32> >
LOffsetTo<UnsizedArrayOf<HBUINT32>, false>
paletteFlagsZ; /* Offset from the beginning of CPAL table to
* the Palette Type Array. Set to 0 if no array
* is provided. */
LOffsetTo<UnsizedArrayOf<HBUINT16> >
LOffsetTo<UnsizedArrayOf<HBUINT16>, false>
paletteLabelZ; /* Offset from the beginning of CPAL table to
* the Palette Labels Array. Set to 0 if no
* array is provided. */
LOffsetTo<UnsizedArrayOf<HBUINT16> >
LOffsetTo<UnsizedArrayOf<HBUINT16>, false>
paletteEntryLabelZ; /* Offset from the beginning of CPAL table to
* the Palette Entry Label Array. Set to 0
* if no array is provided. */
@ -207,7 +207,7 @@ struct CPAL
HBUINT16 numPalettes; /* Number of palettes in the table. */
HBUINT16 numColorRecords; /* Total number of color records, combined for
* all palettes. */
LOffsetTo<UnsizedArrayOf<BGRAColor> >
LOffsetTo<UnsizedArrayOf<BGRAColor>, false>
colorRecordsZ; /* Offset from the beginning of CPAL table to
* the first ColorRecord. */
UnsizedArrayOf<HBUINT16>

2
src/hb-ot-color-svg-table.hh
View File

@ -54,7 +54,7 @@ struct SVGDocumentIndexEntry
* this index entry. */
HBUINT16 endGlyphID; /* The last glyph ID in the range described by
* this index entry. Must be >= startGlyphID. */
LOffsetTo<UnsizedArrayOf<HBUINT8> >
LOffsetTo<UnsizedArrayOf<HBUINT8>, false>
svgDoc; /* Offset from the beginning of the SVG Document Index
* to an SVG document. Must be non-zero. */
HBUINT32 svgDocLength; /* Length of the SVG document.

18
src/hb-ot-layout-common.hh
View File

@ -70,6 +70,11 @@ namespace OT {
* Script, ScriptList, LangSys, Feature, FeatureList, Lookup, LookupList
*/
struct Record_sanitize_closure_t {
hb_tag_t tag;
const void *list_base;
};
template <typename Type>
struct Record
{
@ -77,14 +82,10 @@ struct Record
return tag.cmp (a);
}
struct sanitize_closure_t {
hb_tag_t tag;
const void *list_base;
};
inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
{
TRACE_SANITIZE (this);
const sanitize_closure_t closure = {tag, base};
const Record_sanitize_closure_t closure = {tag, base};
return_trace (c->check_struct (this) && offset.sanitize (c, base, &closure));
}
@ -240,7 +241,7 @@ struct LangSys
}
inline bool sanitize (hb_sanitize_context_t *c,
const Record<LangSys>::sanitize_closure_t * = nullptr) const
const Record_sanitize_closure_t * = nullptr) const
{
TRACE_SANITIZE (this);
return_trace (c->check_struct (this) && featureIndex.sanitize (c));
@ -291,7 +292,7 @@ struct Script
}
inline bool sanitize (hb_sanitize_context_t *c,
const Record<Script>::sanitize_closure_t * = nullptr) const
const Record_sanitize_closure_t * = nullptr) const
{
TRACE_SANITIZE (this);
return_trace (defaultLangSys.sanitize (c, this) && langSys.sanitize (c, this));
@ -526,6 +527,7 @@ struct FeatureParams
FeatureParamsStylisticSet stylisticSet;
FeatureParamsCharacterVariants characterVariants;
} u;
public:
DEFINE_SIZE_STATIC (17);
};
@ -553,7 +555,7 @@ struct Feature
}
inline bool sanitize (hb_sanitize_context_t *c,
const Record<Feature>::sanitize_closure_t *closure = nullptr) const
const Record_sanitize_closure_t *closure = nullptr) const
{
TRACE_SANITIZE (this);
if (unlikely (!(c->check_struct (this) && lookupIndex.sanitize (c))))

4
src/hb-ot-layout-jstf-table.hh
View File

@ -124,7 +124,7 @@ struct JstfPriority
struct JstfLangSys : OffsetListOf<JstfPriority>
{
inline bool sanitize (hb_sanitize_context_t *c,
const Record<JstfLangSys>::sanitize_closure_t * = nullptr) const
const Record_sanitize_closure_t * = nullptr) const
{
TRACE_SANITIZE (this);
return_trace (OffsetListOf<JstfPriority>::sanitize (c));
@ -165,7 +165,7 @@ struct JstfScript
inline const JstfLangSys& get_default_lang_sys (void) const { return this+defaultLangSys; }
inline bool sanitize (hb_sanitize_context_t *c,
const Record<JstfScript>::sanitize_closure_t * = nullptr) const
const Record_sanitize_closure_t * = nullptr) const
{
TRACE_SANITIZE (this);
return_trace (extenderGlyphs.sanitize (c, this) &&