Up until now, the new SSA reflection detection relied on call sites
to propagate which objects (named types, struct fields) used reflection.
For example, given the code:
json.Marshal(new(T))
we would first record that json.Marshal calls reflect.TypeOf,
and then that the user's code called json.Marshal with the type *T.
However, this would not catch a slight variation on the above:
var t T
reflect.TypeOf(t)
t.foo = struct{bar int}{}
Here, type T's fields such as "foo" and "bar" are not obfuscated,
since our logic sees the call site and marks the type T recursively.
However, the unnamed `struct{bar int}` type was still obfuscated,
causing errors such as:
cannot use struct{uKGvcJvD24 int}{} (value of type struct{uKGvcJvD24 int}) as struct{bar int} value in assignment
The solution is to teach the analysis about *ssa.Store instructions
in a similar way to how it already knows about *ssa.Call instructions.
If we see a store where the destination type is marked for reflection,
then we mark the source type as well, fixing the bug above.
This fixes obfuscating github.com/gogo/protobuf/proto.
A number of other Go modules fail with similar errors,
and they look like very similar bugs,
but this particular fix doesn't apply to them.
Future incremental fixes will try to deal with those extra cases.
Fixes#685.
Daniel Martí
10 months ago
committed by
lu4p