tree ffa81b4366ad93237f772bda81cf98f89fca69f4
parent 0709b304e793a5edb4a2c0145f281ecdc20838a4
author aviau <alexandre@alexandreviau.net> 1529003990 -0400
committer Filippo Valsorda <filippo@golang.org> 1536603367 +0000

openpgp: don't treat extra subkey selfsigs as uid sigs

Consider the following packet ordering scenario:
    PUBKEY UID SELFSIG SUBKEY REV SELFSIG

In this scenario, addSubkey would only consume the REV signature after
the subkey, leaving SELFSIG to be read by ReadEntity, which in turn
would add the last SELFSIG to the UID's signatures, which is wrong to do
because this is a SUBKEY SELFSIG, not a UID signature.

Remove "current" from the ReadEntity scope, it should only be visible
to the UserId packet handling code.

Keep the warning about signature packets found before user id packets.
Without it, I would not have found this bug.

Modify addSubKey so that it consumes all signatures following the SUBKEY
packet, keeping eithier the first valid signature (like we did before)
or any valid revocation.

In a follow-up patch, we can improve this further by keeping the
most recent signature, as suggested by RFC4880:
> An implementation that encounters multiple self-signatures on the
> same object may resolve the ambiguity in any way it sees fit, but it
> is RECOMMENDED that priority be given to the most recent self-
> signature.

Fixes golang/go#26449

Change-Id: Id992676ef2363779a7028f4799180efb027fcf47
Reviewed-on: https://go-review.googlesource.com/118957
Reviewed-by: Filippo Valsorda <filippo@golang.org>