Accomplished via the following:
1. Use NETINFO cells to determine if both peers will agree on canonical
status. Prefer connections where they agree to those where they do not.
2. Alter channel_is_better() to prefer older orconns in the case of multiple
canonical connections, and use the orconn with more circuits on it in case
of age ties.
Also perform some hourly accounting on how many of these types of connections
there are and log it at info or notice level.
This defense will cause Cisco, Juniper, Fortinet, and other routers operating
in the default configuration to collapse netflow records that would normally
be split due to the 15 second flow idle timeout.
Collapsing these records should greatly reduce the utility of default netflow
data for correlation attacks, since all client-side records should become 30
minute chunks of total bytes sent/received, rather than creating multiple
separate records for every webpage load/ssh command interaction/XMPP chat/whatever
else happens to be inactive for more than 15 seconds.
The defense adds consensus parameters to govern the range of timeout values
for sending padding packets, as well as for keeping connections open.
The defense only sends padding when connections are otherwise inactive, and it
does not pad connections used solely for directory traffic at all. By default
it also doesn't pad inter-relay connections.
Statistics on the total padding in the last 24 hours are exported to the
extra-info descriptors.
Right now, there's only a mechanism to look for a channel where the
RSA ID matches *and* the ED ID matches. We can add a separate map
later if we want.
This function is allowed to return NULL if the certified key isn't
RSA. But in a couple of places we were treating this as a bug or
internal error, and in one other place we weren't checking for it at
all!
Caught by Isis during code review for #15055. The serious bug was
only on the 15055 branch, thank goodness.
This code stores the ed certs as appropriate, and tries to check
them. The Ed25519 result is not yet used, and (because of its
behavior) this will break RSA authenticate cells. That will get
fixed as we go, however.
This should implement 19157, but it needs tests, and it needs
to get wired in.
In particular, these functions are the ones that set the identity of
a given connection or channel, and/or confirm that we have learned
said IDs.
There's a lot of stub code here: we don't actually need to use the
new keys till we start looking up connections/channels by Ed25519
IDs. Still, we want to start passing the Ed25519 IDs in now, so it
makes sense to add these stubs as part of 15055.
The functions it warns about are:
assert, memcmp, strcat, strcpy, sprintf, malloc, free, realloc,
strdup, strndup, calloc.
Also, fix a few lingering instances of these in the code. Use other
conventions to indicate _intended_ use of assert and
malloc/realloc/etc.
This is a big-ish patch, but it's very straightforward. Under this
clang warning, we're not actually allowed to have a global variable
without a previous extern declaration for it. The cases where we
violated this rule fall into three roughly equal groups:
* Stuff that should have been static.
* Stuff that was global but where the extern was local to some
other C file.
* Stuff that was only global when built for the unit tests, that
needed a conditional extern in the headers.
The first two were IMO genuine problems; the last is a wart of how
we build tests.
This warning triggers on silently promoting a float to a double. In
our code, it's just a sign that somebody used a float by mistake,
since we always prefer double.
This warning, IIUC, means that the compiler doesn't like it when it
sees a NULL check _after_ we've already dereferenced the
variable. In such cases, it considers itself free to eliminate the
NULL check.
There are a couple of tricky cases:
One was the case related to the fact that tor_addr_to_in6() can
return NULL if it gets a non-AF_INET6 address. The fix was to
create a variant which asserts on the address type, and never
returns NULL.
They are no longer "all" digests, but only the "common" digests.
Part of 17795.
This is an automated patch I made with a couple of perl one-liners:
perl -i -pe 's/crypto_digest_all/crypto_common_digests/g;' src/*/*.[ch]
perl -i -pe 's/\bdigests_t\b/common_digests_t/g;' src/*/*.[ch]
An earlier version of these tests was broken; now they're a nicer,
more robust, more black-box set of tests. The key is to have each
test check a handshake message that is wrong in _one_ way.
