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.
This commit adds or improves the module-level documenation for:
buffers.c circuitstats.c command.c connection_edge.c control.c
cpuworker.c crypto_curve25519.c crypto_curve25519.h
crypto_ed25519.c crypto_format.c dircollate.c dirserv.c dns.c
dns_structs.h fp_pair.c geoip.c hibernate.c keypin.c ntmain.c
onion.c onion_fast.c onion_ntor.c onion_tap.c periodic.c
protover.c protover.h reasons.c rephist.c replaycache.c
routerlist.c routerparse.c routerset.c statefile.c status.c
tor_main.c workqueue.c
In particular, I've tried to explain (for each documented module)
what each module does, what's in it, what the big idea is, why it
belongs in Tor, and who calls it. In a few cases, I've added TODO
notes about refactoring opportunities.
I've also renamed an argument, and fixed a few DOCDOC comments.
* FIXES#16823: https://bugs.torproject.org/16823
If an OP were to send a CREATE_FAST cell to an OR, and that
CREATE_FAST cell had unparseable key material, then tor_free() would
be called on the create cell twice. This fix removes the second
(conditional on the key material being bad) call to tor_free(), so
that now the create cell is always freed once, regardless of the status of
the key material.
(This isn't actually a double-free bug, since tor_free() sets its
input to NULL, and has no effect when called with input NULL.)
The two statistics are:
1. number of RELAY cells observed on successfully established
rendezvous circuits; and
2. number of .onion addresses observed as hidden-service
directory.
Both statistics are accumulated over 24 hours, obfuscated by rounding
up to the next multiple of a given number and adding random noise,
and written to local file stats/hidserv-stats.
Notably, no statistics will be gathered on clients or services, but
only on relays.
Also, refactor the way we handle failed handshakes so that this
warning doesn't propagate itself to "onion_skin_client_handshake
failed" and "circuit_finish_handshake failed" and
"connection_edge_process_relay_cell (at origin) failed."
Resolves warning from 9635.
Those used to be normal to receive on hidden service circuits due to bug
1038, but the buggy Tor versions are long gone from the network so we
can afford to resume watching for them. Resolves the rest of bug 1038;
bugfix on 0.2.1.19.
Roger spotted this on tor-dev in his comments on proposal 221.
(Actually, detect DESTROY vs everything else, since arma likes
network timeout indicating failure but not overload indicating failure.)
And add a comment about why conditions that would cause us to drop a
cell should get checked before actions that would cause us to send a
destroy cell.
Spotted by 'cypherpunks'.
And note that these issues have been present since 0.0.8pre1 (commit
0da256ef), where we added a "shutting down" state, and started
responding to all create cells with DESTROY when shutting down.
This code mis-handled the case where a circuit got the same circuit
ID in both directions. I found three instances of it in the
codebase, by grepping for [pn]_circ_id.
Because of the issue in command_process_relay_cell(), this would
have made roughly one circuit in a million completely nonfunctional.
Fixes bug 12195.
Roger spotted this on tor-dev in his comments on proposal 221.
We etect DESTROY vs everything else, since arma likes network
timeout indicating failure but not overload indicating failure.
- Move cell_command_to_string from control.c to command.c.
- Use accessor for global_circuitlist instead of extern.
- Add a struct for cell statistics by command instead of six arrays.
- Split up control_event_circuit_cell_stats by using two helper functions.
- Add TestingEnableCellStatsEvent option.
- Prepare functions for testing.
- Rename a few variables and document a few things better.
Now that circid_t is 4 bytes long, the default integer promotions will
leave it alone when sizeof(int) == 4, which will leave us formatting an
unsigned as an int. That's technically undefined behavior.
Fixes bug 8447 on bfffc1f0fc. Bug not
in any released Tor.
Otherwise, it's possible to create streams or circuits with these
bogus IDs, leading to orphaned circuits or streams, or to ones that
can cause bandwidth DOS problems.
Fixes bug 7889; bugfix on all released Tors.
The unit of work sent to a cpuworker is now a create_cell_t; its
response is now a created_cell_t. Several of the things that call or
get called by this chain of logic now take create_cell_t or
created_cell_t too.
Since all cpuworkers are forked or spawned by Tor, they don't need a
stable wire protocol, so we can just send structs. This saves us some
insanity, and helps p
I'm going to want a generic "onionskin" type and set of wrappers, and
for that, it will be helpful to isolate the different circuit creation
handshakes. Now the original handshake is in onion_tap.[ch], the
CREATE_FAST handshake is in onion_fast.[ch], and onion.[ch] now
handles the onion queue.
This commit does nothing but move code and adjust header files.
If we completed the handshake for the v2 link protocol but wound up
negotiating the wong protocol version, we'd become so confused about
what part of the handshake we were in that we'd promptly die with an
assertion.
This is a fix for CVE-2012-2250; it's a bugfix on 0.2.3.6-alpha.
All servers running that version or later should really upgrade.
Bug and fix from "some guy from France." I tweaked his code slightly
to make it log the IP of the offending node.
Failure to do so left us open to a remotely triggerable assertion
failure. Fixes CVE-2012-2249; bugfix on 0.2.3.6-alpha. Reported by
"some guy from France".
