David Goulet [Tue, 13 Feb 2018 15:29:41 +0000 (10:29 -0500)]
dos: Don't set consensus param if we aren't a public relay
We had this safeguard around dos_init() but not when the consensus changes
which can modify consensus parameters and possibly enable the DoS mitigation
even if tor wasn't a public relay.
Fixes #25223
Signed-off-by: David Goulet <dgoulet@torproject.org>
Nick Mathewson [Mon, 12 Feb 2018 16:08:33 +0000 (11:08 -0500)]
Have tor_addr hashes return a randomized hash for AF_UNSPEC.
We don't expect this to come up very much, but we may as well make
sure that the value isn't predictable (as we do for the other
addresses) in case the issue ever comes up.
David Goulet [Fri, 9 Feb 2018 16:11:41 +0000 (11:11 -0500)]
dos: Exclude known relays from client connection count
This is to avoid positively identifying Exit relays if tor client connection
comes from them that is reentering the network.
One thing to note is that this is done only in the DoS subsystem but we'll
still add it to the geoip cache as a "client" seen. This is done that way so
to avoid as much as possible changing the current behavior of the geoip client
cache since this is being backported.
Closes #25193
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Mon, 5 Feb 2018 15:39:10 +0000 (10:39 -0500)]
geoip: Make geoip_client_cache_total_allocation() return the counter
The HT_FOREACH() is insanely heavy on the CPU and this is part of the fast
path so make it return the nice memory size counter we added in 4d812e29b9b1ec88.
Fixes #25148
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Fri, 2 Feb 2018 22:04:12 +0000 (17:04 -0500)]
dos: We can put less token than the current amount
Becasue the circuit creation burst and rate can change at runtime it is
possible that between two refill of a bucket, we end up setting the bucket
value to less than there currently is.
Fixes #25128
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Mon, 29 Jan 2018 16:50:11 +0000 (11:50 -0500)]
dos: Make circuit rate limit per second, not tenths anymore
Because this touches too many commits at once, it is made into one single
commit.
Remove the use of "tenths" for the circuit rate to simplify things. We can
only refill the buckets at best once every second because of the use of
approx_time() and our token system is set to be 1 token = 1 circuit so make
the rate a flat integer of circuit per second.
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Thu, 25 Jan 2018 14:44:21 +0000 (09:44 -0500)]
dos: Clear connection tracked flag if geoip entry is removed
Imagine this scenario. We had 10 connections over the 24h lifetime of a geoip
cache entry. The lifetime of the entry has been reached so it is about to get
freed but 2 connections remain for it. After the free, a third connection
comes in thus making us create a new geoip entry for that address matching the
2 previous ones that are still alive. If they end up being closed, we'll have
a concurrent count desynch from what the reality is.
To mitigate this probably very rare scenario in practice, when we free a geoip
entry and it has a concurrent count above 0, we'll go over all connections
matching the address and clear out the tracked flag. So once they are closed,
we don't try to decrement the count.
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Thu, 25 Jan 2018 21:32:28 +0000 (16:32 -0500)]
dos: Add the DoSRefuseSingleHopClientRendezvous option
This option refuses any ESTABLISH_RENDEZVOUS cell arriving from a client
connection. Its default value is "auto" for which we can turn it on or off
with a consensus parameter. Default value is 0.
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Thu, 25 Jan 2018 21:14:40 +0000 (16:14 -0500)]
dos: Detect circuit creation denial of service
Add a function that notifies the DoS subsystem that a new CREATE cell has
arrived. The statistics are updated accordingly and the IP address can also be
marked as malicious if it is above threshold.
At this commit, no defense is applied, just detection with a circuit creation
token bucket system.
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Thu, 25 Jan 2018 20:54:58 +0000 (15:54 -0500)]
dos: Initial code of Denial of Service mitigation
This commit introduces the src/or/dos.{c|h} files that contains the code for
the Denial of Service mitigation subsystem. It currently contains basic
functions to initialize and free the subsystem. They are used at this commit.
The torrc options and consensus parameters are defined at this commit and
getters are implemented.
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Thu, 25 Jan 2018 20:44:48 +0000 (15:44 -0500)]
geoip: Add a lookup function for client map entry
The upcoming DoS mitigation subsytem needs to keep information on a per-IP
basis which is also what the geoip clientmap does.
For another subsystem to access that clientmap, this commit adds a lookup
function that returns the entry. For this, the clientmap_entry_t had to be
moved to the header file.
Signed-off-by: David Goulet <dgoulet@torproject.org>
Taylor Yu [Wed, 10 Jan 2018 20:52:04 +0000 (14:52 -0600)]
Work around Travis CI ptrace regression
Travis CI deployed a change that disables ptrace capabilities in
container builds, which prevents LeakSanitizer on clang from working
properly. Set "sudo: required" to force non-container builds for
clang and work around this.
Nick Mathewson [Tue, 19 Dec 2017 18:53:52 +0000 (13:53 -0500)]
Move destroy cells into a separate queue type of their own, to save RAM
We've been seeing problems with destroy cells queues taking up a
huge amount of RAM. We can mitigate this, since while a full packed
destroy cell takes 514 bytes, we only need 5 bytes to remember a
circuit ID and a reason.
Fixes bug 24666. Bugfix on 0.2.5.1-alpha, when destroy cell queues
were introduced.
David Goulet [Wed, 29 Nov 2017 00:02:00 +0000 (19:02 -0500)]
Use local descriptor object to exclude self in path selection
TROVE-2017-12. Severity: Medium
When choosing a random node for a circuit, directly use our router
descriptor to exclude ourself instead of the one in the global
descriptor list. That list could be empty because tor could be
downloading them which could lead to not excluding ourself.
David Goulet [Tue, 21 Nov 2017 15:16:08 +0000 (10:16 -0500)]
hs-v2: Remove any expiring intro from the retry list
TROVE-2017-13. Severity: High.
In the unlikely case that a hidden service could be missing intro circuit(s),
that it didn't have enough directory information to open new circuits and that
an intro point was about to expire, a use-after-free is possible because of
the intro point object being both in the retry list and expiring list at the
same time.
The intro object would get freed after the circuit failed to open and then
access a second time when cleaned up from the expiring list.
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