Our regular DH parameters that we use for circuit and rendezvous
crypto are unchanged. This is yet another small step on the path of
protocol fingerprinting resistance.
(Backport from 0.2.2's 5ed73e3807)
Patch our implementation of tor_lockfile_lock() to handle this case
correctly. Also add a note that blocking behaviour differs from windows
to *nix. Fixes bug 2504, issue pointed out by mobmix.
rransom noticed that a change of ORPort is just as bad as a change of IP
address from a client's perspective, because both mean that the relay is
not available to them while the new information hasn't propagated.
Change the bug1035 fix accordingly.
Also make sure we don't log a bridge's IP address (which might happen
when we are the bridge authority).
It is often not entirely clear what options Tor was built with, so it
might not be immediately obvious which config file Tor is using when it
found one. Log the config file at startup.
When calling circuit_build_times_shuffle_and_store_array, we were
passing a uint32_t as an int. arma is pretty sure that this can't
actually cause a bug, because of checks elsewhere in the code, but
it's best not to pass a uint32_t as an int anyway.
Found by doorss; fix on 0.2.2.4-alpha.
We detect and reject said attempts if there is no chosen exit node or
circuit: connecting to a private addr via a randomly chosen exit node
will usually fail (if all exits reject private addresses), is always
ill-defined (you're not asking for any particular host or service),
and usually an error (you've configured all requests to go over Tor
when you really wanted to configure all _remote_ requests to go over
Tor).
This can also help detect forwarding loop requests.
Found as part of bug2279.
Left circuit_build_times_get_bw_scale() uncommented because it is in the wrong
place due to an improper bug2317 fix. It needs to be moved and renamed, as it
is not a cbt parameter.
To quote arma: "So instead of stopping your CBT from screaming, you're just
going to throw it in the closet and hope you can't hear it?"
Yep. The log message can happen because at 95% point on the curve, we can be
way beyond the max timeout we've seen, if the curve has few points and is
shallow.
Also applied Nick's rule of thumb for rewriting some other notice log messages
to read like how you would explain them to a raving lunatic on #tor who was
shouting at you demanding what they meant. Hopefully the changes live up to
that standard.
If we got a signed digest that was shorter than the required digest
length, but longer than 20 bytes, we would accept it as long
enough.... and then immediately fail when we want to check it.
Fixes bug 2409; bug in 0.2.2.20-alpha; found by piebeer.
Previously if you wanted to say "All messages except network
messages", you needed to say "[*,~net]" and if you said "[~net]" by
mistake, you would get no messages at all. Now, if you say "[~net]",
you get everything except networking messages.
When we added support for separate client tls certs on bridges in
a2bb0bfdd5 we forgot to correctly initialize this when changing
from relay to bridge or vice versa while Tor is running. Fix that
by always initializing keys when the state changes.
Fixes bug 2433.
When we stopped using svn, 0.2.1.x lost the ability to notice its svn
revision and report it in the version number. However, it kept
looking at the micro-revision.i file... so if you switched to master,
built tor, then switched to 0.2.1.x, you'd get a micro-revision.i file
from master reported as an SVN tag. This patch takes out the "include
the svn tag" logic entirely.
Bugfix on 0.2.1.15-rc; fixes bug 2402.
Our regular DH parameters that we use for circuit and rendezvous
crypto are unchanged. This is yet another small step on the path of
protocol fingerprinting resistance.
We need to make sure that the worst thing that a weird consensus param
can do to us is to break our Tor (and only if the other Tors are
reliably broken in the same way) so that the majority of directory
authorities can't pull any attacks that are worse than the DoS that
they can trigger by simply shutting down.
One of these worse things was the cbtnummodes parameter, which could
lead to heap corruption on some systems if the value was sufficiently
large.
This commit fixes this particular issue and also introduces sanity
checking for all consensus parameters.
Our public key functions assumed that they were always writing into a
large enough buffer. In one case, they weren't.
(Incorporates fixes from sebastian)
In dnsserv_resolved(), we carefully made a nul-terminated copy of the
answer in a PTR RESOLVED cell... then never used that nul-terminated
copy. Ouch.
Surprisingly this one isn't as huge a security problem as it could be.
The only place where the input to dnsserv_resolved wasn't necessarily
nul-terminated was when it was called indirectly from relay.c with the
contents of a relay cell's payload. If the end of the payload was
filled with junk, eventdns.c would take the strdup() of the name [This
part is bad; we might crash there if the cell is in a bad part of the
stack or the heap] and get a name of at least length
495[*]. eventdns.c then rejects any name of length over 255, so the
bogus data would be neither transmitted nor altered.
[*] If the name was less than 495 bytes long, the client wouldn't
actually be reading off the end of the cell.
Nonetheless this is a reasonably annoying bug. Better fix it.
Found while looking at bug 2332, reported by doorss. Bugfix on
0.2.0.1-alpha.
The C standard says that INT32_MAX is supposed to be a signed
integer. On platforms that have it, we get the correct
platform-defined value. Our own replacement, however, was
unsigned. That's going to cause a bug somewhere eventually.
Previously, we only looked at up to 128 bytes. This is a bad idea
since socks messages can be at least 256+x bytes long. Now we look at
up to 512 bytes; this should be enough for 0.2.2.x to handle all valid
SOCKS messages. For 0.2.3.x, we can think about handling trickier
cases.
Fixes 2330. Bugfix on 0.2.0.16-alpha.
Right now, Tor routers don't save the maxima values from the
bw_history_t between sessions. That's no good, since we use those
values to determine bandwidth. This code adds a new BWHist.*Maximum
set of values to the state file. If they're not present, we estimate
them by taking the observed total bandwidth and dividing it by the
period length, which provides a lower bound.
This should fix bug 1863. I'm calling it a feature.
Previously, our state parsing code would fail to parse a bwhist
correctly if the Interval was anything other than the default
hardcoded 15 minutes. This change makes the parsing less incorrect,
though the resulting history array might get strange values in it if
the intervals don't match the one we're using. (That is, if stuff was
generated in 15 minute intervals, and we read it into an array that
expects 30 minute intervals, we're fine, since values can be combined
pairwise. But if we generate data at 30 minute intervals and read it
into 15 minute intervals, alternating buckets will be empty.)
Bugfix on 0.1.1.11-alpha.
The trick of looping from i=0..4 , switching on i to set up some
variables, then running some common code is much better expressed by
just calling a function 4 times with 4 sets of arguments. This should
make the code a little easier to follow and maintain here.
An object, you'll recall, is something between -----BEGIN----- and
-----END----- tags in a directory document. Some of our code, as
doorss has noted in bug 2352, could assert if one of these ever
overflowed SIZE_T_CEILING but not INT_MAX. As a solution, I'm setting
a maximum size on a single object such that neither of these limits
will ever be hit. I'm also fixing the INT_MAX checks, just to be sure.
When using libevent 2, we use evdns_base_resolve_*(). When not, we
fake evdns_base_resolve_*() using evdns_resolve_*().
Our old check was looking for negative values (like libevent 2
returns), but our eventdns.c code returns 1. This code makes the
check just test for nonzero.
Note that this broken check was not for _resolve_ failures or even for
failures to _launch_ a resolve: it was for failures to _create_ or
_encode_ a resolve request.
Bug introduced in 81eee0ecfff3dac1e9438719d2f7dc0ba7e84a71; found by
lodger; uploaded to trac by rransom. Bug 2363. Fix on 0.2.2.6-alpha.
This was originally a patch provided by pipe
(http://www.mail-archive.com/or-talk@freehaven.net/msg13085.html) to
provide a method for controllers to query the total amount of traffic
tor has handled (this is a frequently requested piece of information
by relay operators).
C99 allows a syntax for structures whose last element is of
unspecified length:
struct s {
int elt1;
...
char last_element[];
};
Recent (last-5-years) autoconf versions provide an
AC_C_FLEXIBLE_ARRAY_MEMBER test that defines FLEXIBLE_ARRAY_MEMBER
to either no tokens (if you have c99 flexible array support) or to 1
(if you don't). At that point you just use offsetof
[STRUCT_OFFSET() for us] to see where last_element begins, and
allocate your structures like:
struct s {
int elt1;
...
char last_element[FLEXIBLE_ARRAY_MEMBER];
};
tor_malloc(STRUCT_OFFSET(struct s, last_element) +
n_elements*sizeof(char));
The advantages are:
1) It's easier to see which structures and elements are of
unspecified length.
2) The compiler and related checking tools can also see which
structures and elements are of unspecified length, in case they
wants to try weird bounds-checking tricks or something.
3) The compiler can warn us if we do something dumb, like try
to stack-allocate a flexible-length structure.
We were not decrementing "available" every time we did
++next_virtual_addr in addressmap_get_virtual_address: we left out the
--available when we skipped .00 and .255 addresses.
This didn't actually cause a bug in most cases, since the failure mode
was to keep looping around the virtual addresses until we found one,
or until available hit zero. It could have given you an infinite loop
rather than a useful message, however, if you said "VirtualAddrNetwork
127.0.0.255/32" or something broken like that.
Spotted by cypherpunks
We were decrementing "available" twice for each in-use address we ran
across. This would make us declare that we ran out of virtual
addresses when the address space was only half full.
On Windows, we never use pthreads, since it doesn't usually exist,
and when it does it tends to be a little weirdly-behaved. But some
mingw installations have a pthreads installed, so autoconf detects
pthread.h and tells us about it. This would make us include
pthread.h, which could make for trouble when the iffy pthread.h
tried to include config.h.
This patch changes compat.h so that we never include pthread.h on
Windows. Fixes bug 2313; bugfix on 0.1.0.1-rc.
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.
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.
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.
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.
