We now check the handshake certificates unconditionally, and only
report them as _expired_ as a last resort.
(Rationale: if somebody is presenting the wrong identity from a year
ago, it is more interesting that they are presenting the wrong ID
than it is that they are doing so with an expired cert.
We also now report a different error if the certificate is expired,
but its expiration is within the range of reported clock skew.
(Rationale: it's helpful to distinguish this case, so that we can
blame the failure on possible clock skew rather than definitely
attributing it to a misbehaving relay.)
Part of #405.
NETINFO cells, which are sent in every handshake, may contain
timestamps. This patch adds an accessor for the timestamp in the
Netinfo messages, and teaches the tor-proto code how to compute the
minimum clock skew in the code.
The computation isn't terribly precise, but it doesn't need to be:
Tor should work fine if your clock is accurate to within a few
hours.
This patch also notes a Y2038 problem in the protocol: see
torspec#80.
Part of #405.
Each channel now remembers an OwnedChanTarget.
Each circuit now remembers a vector of OwnedChanTarget to represent
the path that it was constructed for.
Part of #415.
Previously coarsetime and the traffic-timestamp feature were
enabled, since they were only required for a small corner of the
guardmgr algorithm.
But in 1.0 and beyond we'll be adding a bunch of other features (eg,
netflow padding, DoS prevention) that will need coarsetime all over
the place.
And since we're going to be doing coarsetime all over the place, the
previous justification for making traffic-timestamping optional (the
tiny performance hit) is no longer relevant.
This lint is IMO inherently ill-conceived.
I have looked for the reasons why this might be thought to be a good
idea and there were basically two (and they are sort of contradictory):
I. "Calling ‘.clone()` on an Rc, Arc, or Weak can obscure the fact
that only the pointer is being cloned, not the underlying data."
This is the wording from
https://rust-lang.github.io/rust-clippy/v0.0.212/#clone_on_ref_ptr
It is a bit terse; we are left to infer why it is a bad idea to
obscure this fact. It seems to me that if it is bad to obscure some
fact, that must be because the fact is a hazard. But why would it be
a hazard to not copy the underlying data ?
In other languages, faliing to copy the underlying data is a serious
correctness hazard. There is a whose class of bugs where things were
not copied, and then mutated and/or reused in multiple places in ways
that were not what the programmer intended. In my experience, this is
a very common bug when writing Python and Javascript. I'm told it's
common in golang too.
But in Rust this bug is much much harder to write. The data inside an
Arc is immutable. To have this bug you'd have use interior mutability
- ie mess around with Mutex or RefCell. That provides a good barrier
to these kind of accidents.
II. "The reason for writing Rc::clone and Arc::clone [is] to make it
clear that only the pointer is being cloned, as opposed to the
underlying data. The former is always fast, while the latter can
be very expensive depending on what is being cloned."
This is the reasoning found here
https://github.com/rust-lang/rust-clippy/issues/2048
This is saying that *not* using Arc::clone is hazardous.
Specifically, that a deep clone is a performance hazard.
But for this argument, the lint is precisely backwards. It's linting
the "good" case and asking for it to be written in a more explicit
way; while the supposedly bad case can be written conveniently.
Also, many objects (in our codebase, and in all the libraries we use)
that are Clone are in fact simply handles. They contain Arc(s) (or
similar) and are cheap to clone. Indeed, that is the usual case.
It does not make sense to distinguish in the syntax we use to clone
such a handle, whether the handle is a transparent Arc, or an opaque
struct containing one or more other handles.
Forcing Arc::clone to be written as such makes for code churn when a
type is changed from Arc<Something> to Something: Clone, or vice
versa.
My proximate motivation is that tls-api wants its inner streams to be
Debug. But in general, I agree with the Rust API Guidelines notion
that almost everything should be Debug.
I have gone for the "dump all the things" approach. A more nuanced
approach would be possible too.
This helps the user distinguish between protocol violations that
happen when connecting to the tor network from those that happen
while connected.
Closes#358.
There was only one use of this, and it was in as-yet-unused relay-only
code.
Removing this type required refactoring the relay onion handshake code
to use its own error type, which is probably clever anyway.
Additionally, refactor the IoError out of tor_cell::Error:
nothing in TorCell created this; it was only used by tor_proto.
This required refactoring in tor_proto to use a new error type. Here I
decided to use a new CodecError for now, though we may refactor that
away soon too.
Nick Mathewson
Ian Jackson
Ian Jackson
trinity-1686a
eta
Yuan Lyu