When calculating max sampled size, Tor would only count the number of
bridges in torrc, without considering that our state file might already
have sampled bridges in it. This caused problems when people swap
bridges, since the following error would trigger:
[warn] Not expanding the guard sample any further; just hit the
maximum sample threshold of 1
The bridges+ipv6-min integration test has a client with bridges:
Bridge 127.0.0.1:5003
Bridge [::1]:5003
which got stuck in guard_selection_have_enough_dir_info_to_build_circuits()
because it couldn't find the descriptor of both bridges.
Specifically, the guard_has_descriptor() function could not find the
node_t of the [::1] bridge, because the [::1] bridge had no identity
digest assigned to it.
After further examination, it seems that during fetching the descriptor
for our bridges, we used the CERTS cell to fill the identity digest of
127.0.0.1:5003 properly. However, when we received a CERTS cell from
[::1]:5003 we actually ignored its identity digest because the
learned_router_identity() function was using
get_configured_bridge_by_addr_port_digest() which was returning the
127.0.0.1 bridge instead of the [::1] bridge (because it prioritizes
digest matching over addrport matching).
The fix replaces get_configured_bridge_by_addr_port_digest() with the
recent get_configured_bridge_by_exact_addr_port_digest() function. It
also relaxes the constraints of the
get_configured_bridge_by_exact_addr_port_digest() function by making it
return bridges whose identity digest is not yet known.
By using the _exact_() function, learned_router_identity() actually
fills in the identity digest of the [::1] bridge, which then allows
guard_has_descriptor() to find the right node_t and verify that the
descriptor is there.
FWIW, in the bridges+ipv6-min test both 127.0.0.1 and [::1] bridges
correspond to the same node_t, which I guess makes sense given that it's
actually the same underlying bridge.
teor [Thu, 2 Mar 2017 04:14:45 +0000 (15:14 +1100)]
Remove delay in hidden service introduction point checks
Make hidden services with 8 to 10 introduction points check for failed
circuits immediately after startup. Previously, they would wait for 5
minutes before performing their first checks.
Fixes bug 21594; bugfix on commit 190aac0eab9 in Tor 0.2.3.9-alpha.
Reported by alecmuffett.
Nick Mathewson [Wed, 1 Mar 2017 20:02:16 +0000 (15:02 -0500)]
Restore correct behavior of 0.3.0.4-rc with bridges+ipv6-min
In that chutney test, the bridge client is configured to connect to
the same bridge at 127.0.0.1:5003 _and_ at [::1]:5003, with no
change in transports.
That meant, I think, that the descriptor is only assigned to the
first bridge when it arrives, and never the second.
Improve descriptor checks in the new guard algorithm.
- Make sure we check at least two guards for descriptor before making
circuits. We typically use the first primary guard for circuits, but
it can also happen that we use the second primary guard (e.g. if we
pick our first primary guard as an exit), so we should make sure we
have descriptors for both of them.
- Remove BUG() from the guard_has_descriptor() check since we now know
that this can happen in rare but legitimate situations as well, and we
should just move to the next guard in that case.
Nick Mathewson [Tue, 28 Feb 2017 15:37:25 +0000 (10:37 -0500)]
Merge branch 'maint-0.2.7-redux' into maint-0.2.8
This is an "ours" merge to avoid taking a version bump, and to
avoid replaying the post-0.2.7.6 history of "maint-0.2.7-redux" onto maint-0.2.8, which already included the relevant changes.
Nick Mathewson [Tue, 14 Feb 2017 17:21:31 +0000 (12:21 -0500)]
Change approach to preventing duplicate guards.
Previously I'd made a bad assumption in the implementation of
prop271 in 0.3.0.1-alpha: I'd assumed that there couldn't be two
guards with the same identity. That's true for non-bridges, but in
the bridge case, we allow two bridges to have the same ID if they
have different addr:port combinations -- in order to have the same
bridge ID running multiple PTs.
Fortunately, this assumption wasn't deeply ingrained: we stop
enforcing the "one guard per ID" rule in the bridge case, and
instead enforce "one guard per <id,addr,port>".
We also needed to tweak our implementation of
get_bridge_info_for_guard, since it made the same incorrect
assumption.
Nick Mathewson [Mon, 13 Feb 2017 20:37:41 +0000 (15:37 -0500)]
Revise the logic for picking the start time for link certs
Since 0.2.4.11-alpha (in 0196647970a91d) we've tried to randomize
the start time to up to some time in the past. But unfortunately we
allowed the start time to be in the future as well, which isn't
really legit.
The new behavior lets the start time be be up to
MAX(cert_lifetime-2days, 0) in the past, but never in the future.
Nick Mathewson [Mon, 27 Feb 2017 14:12:51 +0000 (09:12 -0500)]
Add one other BUG check to try to fix/solve 21369.
Teor thinks that this connection_dirserv_add_dir_bytes_to_outbuf()
might be the problem, if the "remaining" calculation underflows. So
I'm adding a couple of checks there, and improving the casts.
David Goulet [Fri, 24 Feb 2017 14:48:14 +0000 (09:48 -0500)]
hs: Fix bad use of sizeof() when encoding ESTABLISH_INTRO legacy cell
When encoding a legacy ESTABLISH_INTRO cell, we were using the sizeof() on a
pointer instead of using the real size of the destination buffer leading to an
overflow passing an enormous value to the signing digest function.
Fortunately, that value was only used to make sure the destination buffer
length was big enough for the key size and in this case it always was because
of the overflow.
Fixes #21553
Signed-off-by: David Goulet <dgoulet@torproject.org>
projects / thirdparty / tor.git / log
