session.rs try_message_keys

[IIIlllII]

session.rs try_message_keys

[IIIlllII]

Excuse me if I expressed myself poorly.
When receiving an envelope with a counter don't we want to remove a value with fitting counter from our messagekeys only after a successful message decryption? Otherwise an attacker could just create envelopes with a valid sessiontag and force a party to remove all his saved messagekeys by iterating over counter.

[raphaelrobert]

remove(i) will also return the removed value, the (unwrapped) result is stored in mk. The HMAC is then verified using mk.

[raphaelrobert]

Sorry, I misunderstood. I see what you mean now. I think this is fine, because we work on a copy of a session state that was created here:
https://github.com/wireapp/proteus/blob/develop/src/internal/session.rs#L537
If the decryption fails, the copy of the session state is not saved in https://github.com/wireapp/proteus/blob/develop/src/internal/session.rs#L542.

[raphaelrobert]

I'm assuming this issue is resolved and will close it.