evbuffer_pullup does nothing and returns NULL if the caller asks it to
linearize more data than the buffer contains.
Introduced in 9796b9bfa6.
Reported by piebeer; fixed with help from doors.
Libevent 2.0 has a "changelist" feature that avoids making redundant
syscalls if we wind up doing a lot of event_add/event_del operations
on the same fd in a row. Unfortunately, due to a weird design
choice in Linux, it doesn't work right with epoll when multiple fds
refer to the same socket (e.g., one is a dup() of the other). We
don't dup() anything we give to Libevent, though, so it is safe for
us to explicitly turn this feature on.
It's all too easy in C to convert an unsigned value to a signed one,
which will (on all modern computers) give you a huge signed value. If
you have a size_t value of size greater than SSIZE_T_MAX, that is way
likelier to be an underflow than it is to be an actual request for
more than 2gb of memory in one go. (There's nothing in Tor that
should be trying to allocate >2gb chunks.)
If you had TIME_MAX > INT_MAX, and your "time_to_exhaust_bw =
accountingmax/expected_bandwidth_usage * 60" calculation managed to
overflow INT_MAX, then your time_to_consider value could underflow and
wind up being rediculously low or high. "Low" was no problem;
negative values got caught by the (time_to_consider <= 0) check.
"High", however, would get you a wakeup time somewhere in the distant
future.
The fix is to check for time_to_exhaust_bw overflowing INT_MAX, not
TIME_MAX: We don't allow any accounting interval longer than a month,
so if time_to_exhaust_bw is significantly larger than 31*24*60*60, we
can just clip it.
This is a bugfix on 0.0.9pre6, when accounting was first introduced.
It fixes bug 2146, unless there are other causes there too. The fix
is from boboper. (I tweaked it slightly by removing an assignment
that boboper marked as dead, and lowering a variable that no longer
needed to be function-scoped.)
The old logic would have us fetch from authorities if we were refusing
unknown exits and our exit policy was reject*. Instead, we want to
fetch from authorities if we're refusing unknown exits and our exit
policy is _NOT_ reject*.
Fixed by boboper. Fixes more of 2097. Bugfix on 0.2.2.16-alpha.
We use a hash of the identity key to seed a prng to tell when an
accounting period should end. But thanks to the bug998 changes,
clients no longer have server-identity keys to use as a long-term seed
in accounting calculations. In any case, their identity keys (as used
in TLS) were never never fixed. So we can just set the wakeup time
from a random seed instead there. Still open is whether everybody
should be random.
This patch fixes bug 2235, which was introduced in 0.2.2.18-alpha.
Diagnosed with help from boboper on irc.
This is not the most beautiful fix for this problem, but it is the simplest.
Bugfix for 2205. Thanks to Sebastian and Mashael for finding the
bug, and boboper/cypherpunks for figuring out why it was happening
and how to fix it, and for writing a few fixes.
The reason the "streams problem" occurs is due to the complicated
interaction between Tor's congestion control and libevent. At some point
during the experiment, the circuit window is exhausted, which blocks all
edge streams. When a circuit level sendme is received at Exit, it
resumes edge reading by looping over linked list of edge streams, and
calling connection_start_reading() to inform libevent to resume reading.
When the streams are activated again, Tor gets the chance to service the
first three streams activated before the circuit window is exhausted
again, which causes all streams to be blocked again. As an experiment,
we reversed the order in which the streams are activated, and indeed the
first three streams, rather than the last three, got service, while the
others starved.
Our solution is to change the order in which streams are activated. We
choose a random edge connection from the linked list, and then we
activate streams starting from that chosen stream. When we reach the end
of the list, then we continue from the head of the list until our chosen
stream (treating the linked list as a circular linked list). It would
probably be better to actually remember which streams have received
service recently, but this way is simple and effective.
Doing so could make Libevent call Libevent from inside a Libevent
logging call, which is a recipe for reentrant confusion and
hard-to-debug crashes. This would especially hurt if Libevent
debug-level logging is enabled AND the user has a controller
watching for low-severity log messages.
Fix bug 2190; fix on 0.1.0.2-rc.
Doing so could make Libevent call Libevent from inside a Libevent
logging call, which is a recipe for reentrant confusion and
hard-to-debug crashes. This would especially hurt if Libevent
debug-level logging is enabled AND the user has a controller
watching for low-severity log messages.
Fix bug 2190; fix on 0.1.0.2-rc.
Sebastian notes (and I think correctly) that one of our ||s should
have been an &&, which simplifies a boolean expression to decide
whether to replace bridges. I'm also refactoring out the negation at
the start of the expression, to make it more readable.
Pick 5 seconds as the limit. 5 seconds is a compromise here between
making sure the user notices that the bad behaviour is (still) happening
and not spamming their log too much needlessly (the log message is
pretty long). We also keep warning every time if safesocks is
specified, because then the user presumably wants to hear about every
blocked instance.
(This is based on the original patch by Sebastian, then backported to
0.2.2 and with warnings split into their own function.)
Our checks that we don't exceed the 50 KB size limit of extra-info
descriptors apparently failed. This patch fixes these checks and reserves
another 250 bytes for appending the signature. Fixes bug 2183.
Sending a log message to a control port can cause Tor to allocate a buffer,
thereby changing the length of the freelist behind buf_shrink_freelists's back,
thereby causing an assertion to fail.
Fixes bug #1125.
Sending a log message to a control port can cause Tor to allocate a buffer,
thereby changing the length of the freelist behind buf_shrink_freelists's back,
thereby causing an assertion to fail.
Fixes bug #1125.
Having very long single lines with lots and lots of things in them
tends to make files hard to diff and hard to merge. Since our tools
are one-line-at-a-time, we should try to construct lists that way too,
within reason.
This incidentally turned up a few headers in configure.in that we were
for some reason searching for twice.
We would never actually enforce multiplicity rules when parsing
annotations, since the counts array never got entries added to it for
annotations in the token list that got added by earlier calls to
tokenize_string.
Found by piebeer.
We had a spelling discrepancy between the manpage and the source code
for some option. Resolve these in favor of the manpage, because it
makes more sense (for example, HTTP should be capitalized).
The code that makes use of the RunTesting option is #if 0, so setting
this option has no effect. Mark the option as obsolete for now, so that
Tor doesn't list it as an available option erroneously.
Change the default values for collecting directory request statistics and
inlcuding them in extra-info descriptors to 1.
Don't break if we are configured to collect directory request or entry
statistics and don't have a GeoIP database. Instead, print out a notice
and skip initializing the affected statistics code.
We need filtering bufferevent_openssl so that we can wrap around
IOCP bufferevents on Windows. This patch adds a temporary option to
turn on filtering mode, so that we can test it out on non-IOCP
systems to make sure it hasn't got any surprising bugs.
It also fixes some allocation/teardown errors in using
bufferevent_openssl as a filter.
Instead of rejecting a value that doesn't divide into 1 second, round to
the nearest divisor of 1 second and warn.
Document that the option only controls the granularity written by Tor to a
file or console log. It does not (for example) "batch up" log messages to
affect times logged by a controller, times attached to syslog messages, or
the mtime fields on log files.
In the case where old_router == NULL but sdmap has an entry for the
router, we can currently safely infer that the old_router was not a
bridge. Add an assert to ensure that this remains true, and fix the
logic not to die with the tor_assert(old_router) call.
In a2bb0bf we started using a separate client identity key. When we are
in "public server mode" (that means not a bridge) we will use the same
key. Reusing the key without doing the proper refcounting leads to a
segfault on cleanup during shutdown. Fix that.
Also introduce an assert that triggers if our refcount falls below 0.
That should never happen.
We now require that:
- Only actual servers should ever call get_server_identity_key
- If you're being a client or bridge, the client and server keys should
differ.
- If you're being a public relay, the client and server keys
should be the same.
When intro->extend_info is created for an introduction point, it
only starts out with a nickname, not necessarily an identity digest.
Thus, doing router_get_by_digest isn't necessarily safe.
https://trac.torproject.org/projects/tor/ticket/1859
Use router_get_by_digest() instead of router_get_by_hexdigest()
in circuit_discard_optional_exit_enclaves() and
rend_client_get_random_intro(), per Nick's comments.
Using router_get_by_digest() in rend_client_get_random_intro() will
break hidden services published by Tor versions pre 0.1.2.18 and
0.2.07-alpha as they only publish by nickname. This is acceptable
however as these versions only publish to authority tor26 and
don't work for versions in the 0.2.2.x series anyway.
Mainly, this comes from turning two lists that needed to be kept in
synch into a single list of structs. This should save a little RAM,
and make the code simpler.
The old comment was from before I tried a huge pile of crazy stuff to
make the inner loop faster. Short answer: GCC already knows how to
unroll loops pretty well. Other short answer: we should have made the
relay payload size an even multiple of 4, 8, or ideally 16.
There's no reason to keep a time_t and a struct timeval to represent
the same value: highres_created.tv_sec was the same as timestamp_created.
This should save a few bytes per circuit.
The short version is, "where we want to do it, we have nothing real to
chose from and we can't do it easily. Where it's easy to do, we have
no reason to do it yet."
Our old code correctly called bufferevent_flush() on linked
connections to make sure that the other side got an EOF event... but
it didn't call bufferevent_flush() when the connection wasn't
hold_open_until_flushed. Directory connections don't use
hold_open_until_flushed, so the linked exit connection never got an
EOF, so they never sent a RELAY_END cell to the client, and the
client never concluded that data had arrived.
The solution is to make the bufferevent_flush() code apply to _all_
closing linked conns whose partner is not already marked for close.
https://trac.torproject.org/projects/tor/ticket/1859
There are two problems in this bug:
1. When an OP makes a .exit request specifying itself as the exit, and the exit
is not yet listed, Tor gets all the routerinfos needed for the circuit but
discovers in circuit_is_acceptable() that its own routerinfo is not in the
routerdigest list and cannot be used. Tor then gets locked in a cycle of
repeating these two steps. When gathering the routerinfos for a circuit,
specifically when the exit has been chosen by .exit notation, Tor needs to
apply the same rules it uses later on when deciding if it can build a
circuit with those routerinfos.
2. A different bug arises in the above situation when the Tor instance's
routerinfo *is* listed in the routerlist, it shares its nickname with a
number of other Tor nodes, and it does not have 'Named' rights to its
nickname.
So for example, if (i) there are five nodes named Bob in the network, (ii) I
am running one of them but am flagged as 'Unnamed' because someone else
claimed the 'Bob' nickname first, and (iii) I run my Tor as both client
and exit the following can happen to me:
- I go to www.evil.com
- I click on a link www.evil.com.bob.exit
- My request will exit through my own Tor node rather than the 'Named'
node Bob or any of the others.
- www.evil.com now knows I am actually browsing from the same computer
that is running my 'Bob' node
So to solve both issues we need to ensure:
- When fulfilling a .exit request we only choose a routerinfo if it exists in
the routerlist, even when that routerinfo is ours.
- When getting a router by nickname we only return our own router information
if it is not going to be used for building a circuit.
We ensure this by removing the special treatment afforded our own router in
router_get_by_nickname(). This means the function will only return the
routerinfo of our own router if it is in the routerlist built from authority
info and has a unique nickname or is bound to a non-unique nickname.
There are some uses of router_get_by_nickname() where we are looking for the
router by name because of a configuration directive, specifically local
declaration of NodeFamilies and EntryNodes and other routers' declaration of
MyFamily. In these cases it is not at first clear if we need to continue
returning our own routerinfo even if our router is not listed and/or has a
non-unique nickname with the Unnamed flag.
The patch treats each of these cases as follows:
Other Routers' Declaration of MyFamily
This happens in routerlist_add_family(). If another router declares our router
in its family and our router has the Unnamed flag or is not in the routerlist
yet, should we take advantage of the fact that we know our own routerinfo to
add us in anyway? This patch says 'no, treat our own router just like any
other'. This is a safe choice because it ensures our client has the same view
of the network as other clients. We also have no good way of knowing if our
router is Named or not independently of the authorities, so we have to rely on
them in this.
Local declaration of NodeFamilies
Again, we have no way of knowing if the declaration 'NodeFamilies
Bob,Alice,Ringo' refers to our router Bob or the Named router Bob, so we have
to defer to the authorities and treat our own router like any other.
Local declaration of NodeFamilies
Again, same as above. There's also no good reason we would want our client to
choose it's own router as an entry guard if it does not meet the requirements
expected of any other router on the network.
In order to reduce the possibility of error, the patch also replaces two
instances where we were using router_get_by_nickname() with calls to
router_get_by_hexdigest() where the identity digest of the router
is available.
First start of a fix for bug2001, but my test network still isn't
working: the client and the server send each other VERSIONS cells,
but never notice that they got them.
Currently the unit tests test_util_spawn_background_* assume that they
are run from the Tor build directory. This is not the case when running
make distcheck, so the test will fail. This problem is fixed by autoconf
setting BUILDDIR to be the root of the Tor build directory, and this
preprocessor variable being used to specify the absolute path to
test-child. Also, in test-child, do not print out argv[0] because this will
no longer be predictable. Found by Sebastian Hahn.
* Make tor_tls_context_new internal to tortls.c, and return the new
tor_tls_context_t from it.
* Add a public tor_tls_context_init wrapper function to replace it.
- Responsibility of clearing hex_errno is no longer with caller
- More conservative bounds checking
- Length requirement of hex_errno documented
- Output format documented
Some of these functions only work for routerinfo-based nodes, and as
such are only usable for advisory purposes. Fortunately, our uses
of them are compatible with this limitation.
Also, make the NodeFamily option into a list of routersets. This
lets us git rid of router_in_nickname_list (or whatever it was
called) without porting it to work with nodes, and also lets people
specify country codes and IP ranges in NodeFamily
This was the only flag in routerstatus_t that we would previously
change in a routerstatus_t in a consensus. We no longer have reason
to do so -- and probably never did -- as you can now confirm more
easily than you could have done by grepping for is_running before
this patch.
The name change is to emphasize that the routerstatus_t is_running
flag is only there to tell you whether the consensus says it's
running, not whether it *you* think it's running.
A node_t is an abstraction over routerstatus_t, routerinfo_t, and
microdesc_t. It should try to present a consistent interface to all
of them. There should be a node_t for a server whenever there is
* A routerinfo_t for it in the routerlist
* A routerstatus_t in the current_consensus.
(note that a microdesc_t alone isn't enough to make a node_t exist,
since microdescriptors aren't usable on their own.)
There are three ways to get a node_t right now: looking it up by ID,
looking it up by nickname, and iterating over the whole list of
microdescriptors.
All (or nearly all) functions that are supposed to return "a router"
-- especially those used in building connections and circuits --
should return a node_t, not a routerinfo_t or a routerstatus_t.
A node_t should hold all the *mutable* flags about a node. This
patch moves the is_foo flags from routerinfo_t into node_t. The
flags in routerstatus_t remain, but they get set from the consensus
and should not change.
Some other highlights of this patch are:
* Looking up routerinfo and routerstatus by nickname is now
unified and based on the "look up a node by nickname" function.
This tries to look only at the values from current consensus,
and not get confused by the routerinfo_t->is_named flag, which
could get set for other weird reasons. This changes the
behavior of how authorities (when acting as clients) deal with
nodes that have been listed by nickname.
* I tried not to artificially increase the size of the diff here
by moving functions around. As a result, some functions that
now operate on nodes are now in the wrong file -- they should
get moved to nodelist.c once this refactoring settles down.
This moving should happen as part of a patch that moves
functions AND NOTHING ELSE.
* Some old code is now left around inside #if 0/1 blocks, and
should get removed once I've verified that I don't want it
sitting around to see how we used to do things.
There are still some unimplemented functions: these are flagged
with "UNIMPLEMENTED_NODELIST()." I'll work on filling in the
implementation here, piece by piece.
I wish this patch could have been smaller, but there did not seem to
be any piece of it that was independent from the rest. Moving flags
forces many functions that once returned routerinfo_t * to return
node_t *, which forces their friends to change, and so on.
The node_t type is meant to serve two key functions:
1) Abstracting difference between routerinfo_t and microdesc_t
so that clients can use microdesc_t instead of routerinfo_t.
2) Being a central place to hold mutable state about nodes
formerly held in routerstatus_t and routerinfo_t.
This patch implements a nodelist type that holds a node for every
router that we would consider using.
