Deprecated in 0.2.9.2-alpha, this commits changes it as OBSOLETE() and cleans
up the code associated with it.
Partially fixes#22060
Signed-off-by: David Goulet <dgoulet@torproject.org>
Deprecated in 0.2.9.2-alpha, this commits changes it as OBSOLETE() and cleans
up the code associated with it.
Partially fixes#22060
Signed-off-by: David Goulet <dgoulet@torproject.org>
Deprecated in 0.2.9.2-alpha, this commits changes it as OBSOLETE() and cleans
up the code associated with it.
Partially fixes#22060
Signed-off-by: David Goulet <dgoulet@torproject.org>
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.
Add a new helper function route_len_for_purpose(), which explicitly
lists all of the known circuit purposes for a circuit with a chosen
exit node (unlike previously, where the default route length for a
chosen exit was DEFAULT_ROUTE_LEN + 1 except for two purposes). Add a
non-fatal assertion for unhandled purposes that conservatively returns
DEFAULT_ROUTE_LEN + 1.
Add copious comments documenting which circuits need an extra hop and
why.
Thanks to nickm and dgoulet for providing background information.
Bug 21242 occurred because we asserted that extend_info_from_node()
had succeeded...even though we already had the code to handle such a
failure. We fixed that in 93b39c5162.
But there were four other cases in our code where we called
extend_info_from_node() and either tor_assert()ed that it returned
non-NULL, or [in one case] silently assumed that it returned
non-NULL. That's not such a great idea. This patch makes those
cases check for a bug of this kind instead.
Fixes bug 21372; bugfix on 0.2.3.1-alpha when
extend_info_from_node() was introduced.
This assertion triggered in the (error) case where we got a result
from guards_choose_guard() without a descriptor. That's not
supposed to be possible, but it's not worth crashing over.
That way, when we are parsing the options and LearnCircuitBuildTimeout is set
to 0, we don't assert trying to get the options list with get_options().
Fixes#21062
Signed-off-by: David Goulet <dgoulet@torproject.org>
This is an important thing I hadn't considered when writing prop271:
sometimes you have to restrict what guard you use for a particular
circuit. Most frequently, that would be because you plan to use a
certain node as your exit, and so you can't choose that for your
guard.
This change means that the upgrade-waiting-circuits algorithm needs
a slight tweak too: circuit A cannot block circuit B from upgrading
if circuit B needs to follow a restriction that circuit A does not
follow.
George pointed out that (-1,0,1) for (never usable, maybe usable
later, usable right now) was a pretty rotten convention that made
the code harder to read.
This patch makes two absolutely critical changes:
- If an ed25519 identity is not as expected when creating a channel,
we call that channel unsuccessful and close it.
- When a client creating a channel or an extend cell for a circuit, we
only include the ed25519 identity if we believe that the node on
the other side supports ed25519 link authentication (from
#15055). Otherwise we will insist on nodes without the right
link protocol authenticating themselves.
- When deciding to extend to another relay, we only upgrade the
extend to extend by ed25519 ID when we know the ed25519 ID _and_
we know that the other side can authenticate.
This patch also tells directory servers, when probing nodes, to
try to check their ed25519 identities too (if they can authenticate
by ed25519 identity).
Also, handle the case where we connect by RSA Id, and learn the
ED25519 ID for the node in doing so.
I need to be able to turn on Ed25519 support in client generation
of extend cells so I can test it, but leave it off-by-default until
enough clients support it for us to turn it on for a bunch at once.
This is part of #15056 / prop#220.
- forbid extending to the previous hop by Ed25519 ID.
- If we know the Ed25519 ID for the next hop and the client doesn't,
insist on the one from the consensus.
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 patch doesn't cover every case; omitted cases are marked with
"XXXX prop271", as usual. It leaves both the old interface and the
new interface for guard status notification, since they don't
actually work in the same way: the new API wants to be told when a
circuit has failed or succeeded, whereas the old API wants to know
when a channel has failed or succeeded.
I ran into some trouble with directory guard stuff, since when we
pick the directory guard, we don't actually have a circuit to
associate it with. I solved that by allowing guard states to be
associated with directory connections, not just circuits.
Here we add a little bit of state to origin circuits, and set up
the necessary functions for the circuit code to call in order to
find guards, use guards, and decide when circuits can be used.
There's also an incomplete function for the hard part of the
circuit-maintenance code, where we figure out whether any waiting
guards are ready to become usable.
(This patch finally uses the handle.c code to make safe handles to
entry_guard_t objects, so that we are allowed to free an
entry_guard_t without checking whether any origin_circuit_t is
holding a reference to it.)
This patch is just:
* Code movement
* Adding headers here and there as needed
* Adding a bridges_free_all() with a call to it.
It breaks compilation, since the bridge code needed to make exactly
2 calls into entrynodes.c internals. I'll fix those in the next
commit.
The entry_guard_t structure should really be opaque, so that we
can change its contents and have the rest of Tor not care.
This commit makes it "mostly opaque" -- circpathbias.c can still see
inside it. (I'm making circpathbias.c exempt since it's the only
part of Tor outside of entrynodes.c that made serious use of
entry_guard_t internals.)
