David Goulet [Mon, 3 Jun 2019 18:31:51 +0000 (14:31 -0400)]
sendme: Do not decrement window in a log_debug()
If "Log debug ..." is not set, the decrement never happens. This lead to the
package/deliver window to be out of sync at the stream level and thus breaking
the connection after 50+ cells.
Fixes #30628
Signed-off-by: David Goulet <dgoulet@torproject.org>
Nick Mathewson [Fri, 31 May 2019 16:19:29 +0000 (12:19 -0400)]
num_bridges_usable(): only count configured bridges.
When this function was implemented, it counted all the entry guards
in the bridge set. But this included previously configured bridges,
as well as currently configured ones! Instead, only count the
_filtered_ bridges (ones that are configured and possibly reachable)
as maybe usable.
Nick Mathewson [Wed, 29 May 2019 15:25:47 +0000 (11:25 -0400)]
Shutdown libevent _after_ the subsystems.
This is necessary since shutting down libevent frees some pointer
that the subsystems want to free themselves. A longer term solution
will be to turn the evloop module into a subsystem itself, but for
now it is best to do the minimal fix.
Nick Mathewson [Wed, 29 May 2019 15:00:09 +0000 (11:00 -0400)]
Make get_proxy_type() connection-specific
Previously, we were looking at our global settings to see what kind
of proxy we had. But doing this would sometimes give us the wrong
results when we had ClientTransportPlugin configured but we weren't
using it for a particular connection. In several places in the
code, we had added checks to see if we were _really_ using a PT or
whether we were using a socks proxy, but we had forgotten to do so
in at least once case. Instead, since every time we call this
function we are asking about a single connection, it is probably
best just to make this function connection-specific.
If tor is compiled on a system with neither vasprintf nor _vscprintf,
the fallback implementation exposes a logic flaw which prevents
proper usage of strings longer than 127 characters:
* tor_vsnprintf returns -1 if supplied buffer is not large enough,
but tor_vasprintf uses this function to retrieve required length
* the result of tor_vsnprintf is not properly checked for negative
return values
Both aspects together could in theory lead to exposure of uninitialized
stack memory in the resulting string. This requires an invalid format
string or data that exceeds integer limitations.
Fortunately tor is not even able to run with this implementation because
it runs into asserts early on during startup. Also the unit tests fail
during a "make check" run.
Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
[backported to 0.2.9 by nickm]
Use MAP_INHERIT_ZERO or MAP_INHERIT_NONE if available.
Fixes assertion failure in tests on NetBSD:
slow/prob_distr/stochastic_log_logistic: [forking] May 25 03:56:58.091 [err] tor_assertion_failed_(): Bug: src/lib/crypt_ops/crypto_rand_fast.c:184: crypto_fast_rng_new_from_seed: Assertion inherit != INHERIT_RES_KEEP failed; aborting. (on Tor 0.4.1.1-alpha-dev 29955f13e5bc8e61)
May 25 03:56:58.091 [err] Bug: Assertion inherit != INHERIT_RES_KEEP failed in crypto_fast_rng_new_from_seed at src/lib/crypt_ops/crypto_rand_fast.c:184: . (Stack trace not available) (on Tor 0.4.1.1-alpha-dev 29955f13e5bc8e61)
[Lost connection!]
Nick Mathewson [Fri, 17 May 2019 15:03:16 +0000 (11:03 -0400)]
Make sure that we send at least some random data in RELAY_DATA cells
Proposal 289 prevents SENDME-flooding by requiring the other side to
authenticate the data it has received. But this data won't actually
be random if they are downloading a known resource. "No problem",
we said, "let's fell the empty parts of our cells with some
randomness!" and we did that in #26871.
Unfortunately, if the relay data payloads are all completely full,
there won't be any empty parts for us to randomize.
Therefore, we now pick random "randomness windows" between
CIRCWINDOW_INCREMENT/2 and CIRCWINDOW_INCREMENT. We remember whether we have
sent a cell containing at least 16 bytes of randomness in that window. If we
haven't, then when the window is exhausted, we send one. (This window approach
is designed to lower the number of rng checks we have to do. The number 16 is
pulled out of a hat to change the attacker's guessing difficulty to
"impossible".)
Nick Mathewson [Thu, 23 May 2019 18:36:01 +0000 (14:36 -0400)]
cov-test-determinism: use the same RNG seed as in travis.yml
We added this facility so that we could get deterministic PRNG
behavior for coverage testing on tests that use a replaced PRNG.
We need to have our coverage determinism tool test for this as well.
Nick Mathewson [Wed, 15 May 2019 18:58:46 +0000 (14:58 -0400)]
Coverage: do not include test-rebind in coverage builds.
Because it invokes the Tor mainloop, it does unpredictable things to
test coverage of a lot of code that it doesn't actually test at
all. (It is more an integration test than anything else.)
Nick Mathewson [Wed, 15 May 2019 12:28:25 +0000 (08:28 -0400)]
In coverage builds, use branch-free timeradd() and timersub()
The ordinary definitions of timeradd() and timersub() contain a
branch. However, in coverage builds, this means that we get spurious
complaints about partially covered basic blocks, in a way that makes
our coverage determinism harder to check.
Nick Mathewson [Wed, 15 May 2019 12:27:02 +0000 (08:27 -0400)]
In coverage builds, avoid basic-block complexity in log_debug
Ordinarily we skip calling log_fn(LOG_DEBUG,...) if debug logging is
completely disabled. However, in coverage builds, this means that
we get spurious complaints about partially covered basic blocks, in
a way that makes our coverage determinism harder to check.
David Goulet [Wed, 22 May 2019 15:05:36 +0000 (11:05 -0400)]
sendme: Add non fatal asserts for extra safety
Two non fatal asserts are added in this commit. First one is to see if the
SENDME digest list kept on the circuit for validation ever grows bigger than
the maximum number of expected SENDME on a circuit (currently 10).
The second one is to know if we ever send more than one SENDME at a time on a
circuit. In theory, we shouldn't but if we ever do, the v1 implementation
wouldn't work because we only keep one single cell digest (the previous cell
to the SENDME) on the circuit/cpath. Thus, sending two SENDME consecutively
will lead to a mismatch on the other side because the same cell digest would
be use and thus the circuit would collapse.
Finally, add an extra debug log in case we emit a v0 which also includes the
consensus emit version in that case.
Part of #30428
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Tue, 21 May 2019 19:19:30 +0000 (15:19 -0400)]
sendme: Clarify how sendme_circuit_cell_is_next() works
Commit 4ef8470fa5480d3b was actually reverted before because in the end we
needed to do this minus 1 check on the window.
This commit clarifies that in the code, takes the useful comment changes from 4ef8470fa5480d3b and makes sendme_circuit_cell_is_next() private since it
behaves in a very specific way that one external caller might expect.
Part of #30428.
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Wed, 15 May 2019 14:16:05 +0000 (10:16 -0400)]
sendme: Properly record SENDMEs on both edges
Turns out that we were only recording the "b_digest" but to have
bidirectionnal authenticated SENDMEs, we need to use the "f_digest" in the
forward cell situation.
Because of the cpath refactoring, this commit plays with the crypt_path_ and
relay_crypto_t API a little bit in order to respect the abstractions.
Previously, we would record the cell digest as the SENDME digest in the
decrypt cell function but to avoid code duplication (both directions needs to
record), we now do that right after iff the cell is recognized (at the edge).
It is now done in circuit_receive_relay_cell() instead.
We now also record the cell digest as the SENDME digest in both relay cell
encryption functions since they are split depending on the direction.
relay_encrypt_cell_outbound() and relay_encrypt_cell_inbound() need to
consider recording the cell digest depending on their direction (f vs b
digest).
Fixes #30428
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Tue, 7 May 2019 13:44:10 +0000 (09:44 -0400)]
sendme: Never fallback to v0 if unknown version
There was a missing cell version check against our max supported version. In
other words, we do not fallback to v0 anymore in case we do know the SENDME
version.
We can either handle it or not, never fallback to the unauthenticated version
in order to avoid gaming the authenticated logic.
Add a unit tests making sure we properly test that and also test that we can
always handle the default emit and accepted versions.
Fixes #30428
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Tue, 7 May 2019 13:19:41 +0000 (09:19 -0400)]
sendme: Validate v1 SENDMEs on both client and exit side
The validation of the SENDME cell is now done as the very first thing when
receiving it for both client and exit. On failure to validate, the circuit is
closed as detailed in the specification.
Part of #30428
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Tue, 7 May 2019 13:16:39 +0000 (09:16 -0400)]
sendme: Record cell digest on both client and exit
It turns out that only the exit side is validating the authenticated SENDME v1
logic and never the client side. Which means that if a client ever uploaded
data towards an exit, the authenticated SENDME logic wouldn't apply.
For this to work, we have to record the cell digest client side as well which
introduced a new function that supports both type of edges.
This also removes a test that is not valid anymore which was that we didn't
allow cell recording on an origin circuit (client).
Part of #30428
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Thu, 9 May 2019 17:01:15 +0000 (13:01 -0400)]
hs: Get rid of duplicate hs_cell_introd_ack_status_t
This enum was the exact same as hs_intro_ack_status_t that was removed at the
previous commit. It was used client side when parsing the INTRODUCE_ACK cell.
Now, the entire code dealing with the INTRODUCE_ACK cell (both sending and
receiving) have been modified to all use the same ABI defined in the trunnel
introduce1 file.
Finally, the client will default to the normal behavior when receiving an
unknown NACK status code which is to note down that we've failed and re-extend
to the next intro point. This way, unknown status code won't trigger a
different behavior client side.
Part of #30454.
Signed-off-by: David Goulet <dgoulet@torproject.org>
David Goulet [Thu, 9 May 2019 16:55:52 +0000 (12:55 -0400)]
hs: Define INTRODUCE_ACK status code in trunnel
Remove the hs_intro_ack_status_t enum and move the value into trunnel. Only
use these values from now on in the intro point code.
Interestingly enough, the client side also re-define these values in hs_cell.h
with the hs_cell_introd_ack_status_t enum. Next commit will fix that and force
to use the trunnel ABI.
Part of #30454
Signed-off-by: David Goulet <dgoulet@torproject.org>
projects / thirdparty / tor.git / log
