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Fix reflection verifier: missing VerifyField calls and OOB root read #9046

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Fix reflection verifier: missing VerifyField calls and OOB root read #9046

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8 changes: 8 additions & 0 deletions src/reflection.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -240,6 +240,9 @@ static bool VerifyObject(flatbuffers::Verifier& v,
return false;
}
} else {
if (!table->VerifyField<uoffset_t>(v, field_def->offset(),
sizeof(uoffset_t)))
return false;
if (!VerifyObject(v, schema, *child_obj,
flatbuffers::GetFieldT(*table, *field_def),
field_def->required())) {
Expand All @@ -249,6 +252,9 @@ static bool VerifyObject(flatbuffers::Verifier& v,
break;
}
case reflection::Union: {
if (!table->VerifyField<uoffset_t>(v, field_def->offset(),
sizeof(uoffset_t)))
return false;
// get union type from the prev field
voffset_t utype_offset = field_def->offset() - sizeof(voffset_t);
auto utype = table->GetField<uint8_t>(utype_offset, 0);
Expand Down Expand Up @@ -786,6 +792,7 @@ Offset<const Table*> CopyTable(FlatBufferBuilder& fbb,
bool Verify(const reflection::Schema& schema, const reflection::Object& root,
const uint8_t* const buf, const size_t length,
const uoffset_t max_depth, const uoffset_t max_tables) {
if (length < sizeof(uoffset_t)) return false;
Verifier v(buf, length, max_depth, max_tables);
return VerifyObject(v, schema, root, flatbuffers::GetAnyRoot(buf),
/*required=*/true);
Expand All @@ -795,6 +802,7 @@ bool VerifySizePrefixed(const reflection::Schema& schema,
const reflection::Object& root,
const uint8_t* const buf, const size_t length,
const uoffset_t max_depth, const uoffset_t max_tables) {
if (length < sizeof(uoffset_t) * 2) return false;
Verifier v(buf, length, max_depth, max_tables);
return VerifyObject(v, schema, root, flatbuffers::GetAnySizePrefixedRoot(buf),
/*required=*/true);
Expand Down
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