We've had over two months to fix them, and didn't. Now we need
0.2.3.x stable. Yes, it would be cool to get this working in
0.2.3.x, but not at the expense of delaying every other feature that
_does_ work in 0.2.3.x. We can do a real fix in 0.2.4.
This is important, since otherwise an attacker can use timing info
to probe the internal network.
Also, add an option (ExtendAllowPrivateAddresses) so that
TestingTorNetwork won't break.
Fix for bug 6710; bugfix on all released versions of Tor.
Move extend_info_from_router() from circuitbuild.c to router.c and
make it static.
Add get_configured_bridge_by_orports_digest() and have
get_configured_bridge_by_routerinfo() and
node_is_a_configured_bridge() use it. We now consider all OR ports of
a bridge when looking for it.
Move node_get_*_orport to nodelist.c.
Fix a cut'n'paste error in header of nodelist.h.
Add node_assert_ok().
Add router_get_all_orports(). It's duplicating code from
node_get_all_orports(). Worth fixing at the cost of complicating the
API slightly?
Failure to do this would lead to double-free cases and similar,
especially when the exit's DNS was broken. See bug 6472 for full
details; this is a fix for 6472.
Anonymous patch from "cypherpunks" on trac.
Long ago, before we had cell queues, it was necessary to maybe call
connection_handle_write() from connectino_write_to_buf_impl() on OR
connections, so that we wouldn't get into a loop of reading infinite
amounts of data and queueing it all on an outbuf before bothering to
write any data.
If that doesn't sounds like what our code does now, you're right:
right now, we won't stick more than OR_CONN_HIGHWATER bytes of cells
on an outbuf, and we won't suck more than CELL_QUEUE_HIGHWATER_SIZE
cells off any edge connection. So, there's no more call for that
code.
Removing this code will simplify our data flow, and that should be
something we can all get behind.
The warning fixes are:
- Only define issetugid if it's missing.
- Explicitly ignore the return value of writev.
- Explicitly cast the retval of readlink() to int.
The 64-bit problems are related to just storing a size_t in an int. Not cool! Use a size_t instead.
Fix for bug 6379. Bugfix on 0.2.0.20-rc, which introduced openbsd-malloc.
Extend cells aren't allowed to have a stream_id, but we were only
blocking them when they had a stream_id that corresponded to a
connection. As far as I can tell, this change is harmless: it will
make some kinds of broken clients not work any more, but afaik nobody
actually make a client that was broken in that way.
Found while hunting for other places where we made the same mistake
as in 6271.
Bugfix on d7f50337c1 back from May 2003, which introduced
telescoping circuit construction into 0.0.2pre8.
Thanks to the changes we started making with SocksPort and friends
in 0.2.3.3-alpha, any of our code that did "if (options->Sockport)"
became wrong, since "SocksPort 0" would make that test true whereas
using the default SocksPort value would make it false. (We didn't
actually do "if (options->SockPort)" but we did have tests for
TransPort. When we moved DirPort, ORPort, and ControlPort over to
the same system in 0.2.3.9-alpha, the problem got worse, since our
code is littered with checks for DirPort and ORPort as booleans.
This code renames the current linelist-based FooPort options to
FooPort_lines, and adds new FooPort_set options which get set at
parse-and-validate time on the or_options_t. FooPort_set is true
iff we will actually try to open a listener of the given type. (I
renamed the FooPort options rather than leave them alone so that
every previous user of a FooPort would need to get inspected, and so
that any new code that forgetfully uses FooPort will need fail to
compile.)
Fix for bug 6507.
The old approach, because of its "tmp >= rand_bw &&
!i_has_been_chosen" check, would run through the second part of the
loop slightly slower than the first part. Now, we remove
i_has_been_chosen, and instead set rand_bw = UINT64_MAX, so that
every instance of the loop will do exactly the same amount of work
regardless of the initial value of rand_bw.
Fix for bug 6538.
This should make our preferred solution to #6538 easier to
implement, avoid a bunch of potential nastiness with excessive
int-vs-double math, and generally make the code there a little less
scary.
"But wait!" you say. "Is it really safe to do this? Won't the
results come out differently?"
Yes, but not much. We now round every weighted bandwidth to the
nearest byte before computing on it. This will make every node that
had a fractional part of its weighted bandwidth before either
slighty more likely or slightly less likely. Further, the rand_bw
value was only ever set with integer precision, so it can't
accurately sample routers with tiny fractional bandwidth values
anyway. Finally, doing repeated double-vs-uint64 comparisons is
just plain sad; it will involve an implicit cast to double, which is
never a fun thing.
I don't personally agree that this is likely to be easy to exploit,
and some initial experimention I've done suggests that cache-miss
times are just plain too fast to get useful info out of when they're
mixed up with the rest of Tor's timing noise. Nevertheless, I'm
leaving Robert's initial changelog entry in the git history so that he
can be the voice of reason if I'm wrong. :)
$ make V=1 # will temporarily disable them
otherwise you see:
CC foo.c
rather than the giant long bulid line.
This makes it significantly easier to spot compiler warnings etc.
Additionally, make them conditional, so we won't error on automake <
1.11
(commits squashed by nickm.)
In 0.2.3.18-rc, we started warning on this case while building a
list of missing microdescriptor digests. That turned out to spam
the logs; instead let's warn at parse time.
Partial fix for bug 6404.
The spec requires that every router in a microdesc consensus have an
m line; we weren't obeying that spec.
This creates a new consensus method (13) to allow voting to continue
to work right. Partial fix for bug 6404; fix on 0.2.2.6-alpha.
This is based on a pair of patches from A. Costa. I couldn't apply
those directly, since they changed the generated *roff files, not
the asciidoc source.
Fixes Tor bug 6500 and Debian bug 683359.
Test for config option AuthDirPublishIPv6 == 1 rather than for running
as a bridge authority when deciding whether to care or not about IPv6
OR ports in descriptors.
Implements enhancement #6406.
This avoids a possible crash bug in flush_from_first_active_circuit.
Fixes bug 6341; bugfix on 0.2.2.7-alpha.
Bug reported and fixed by a pseudonymous user on IRC.
I only check on circuits, not streams, since bloating your stream
window past the initial circuit window can't help you much.
Also, I compare to CIRCWINDOW_START_MAX so we don't have surprising
races if we lower CIRCWINDOW_START for an experiment.
The SMARTLIST_FOREACH macro is more convenient than BEGIN/END when
you have a nice short loop body, but using it for long bodies makes
your preprocessor tell the compiler that all the code is on the same
line. That causes grief, since compiler warnings and debugger lines
will all refer to that one line.
So, here's a new style rule: SMARTLIST_FOREACH blocks need to be
short.
- Add a changes/ file.
- Make it compile under --enable-gcc-warnings.
- Update the file-level documentation of src/or/transports.c.
- Only update descriptor if at least a managed proxy was configured.
- Add our external IP address to the extra-info descriptor instead of 0.0.0.0.
This could result in bizarre window values. Report and patch
contributed pseudymously. Fixes part of bug 6271. This bug was
introduced before the first Tor release, in svn commit r152.
(bug 6271, part a.)
This reverts commit c32ec9c425.
It turns out the two sides of the circuit don't actually stay in sync,
so it is perfectly normal for the circuit window on the exit relay to
grow to 2000+. We should fix that bug and then reconsider this patch.
I only check on circuits, not streams, since bloating your stream
window past the initial circuit window can't help you much.
Also, I compare to CIRCWINDOW_START_MAX so we don't have surprising
races if we lower CIRCWINDOW_START for an experiment.
With glibc 2.15 and clang 3.0, I get warnings from where we use the
strcpsn implementation in the header as strcspn(string, "="). This
is apparently because clang sees that part of the strcspn macro
expands to "="[2], and doesn't realize that that part of the macro
is only evaluated when "="[1] != 0.
The functions parse_{s,c}method_line() were using
tor_addr_port_lookup() which is capable of doing DNS lookups. DNS
lookups should not be necessary when parsing {C,S}METHOD lines.
The code that detected the source of a remapped address checked that
an address mapping's source was a given rewrite rule if addr_orig had
no .exit, and addr did have a .exit after processing that rule. But
addr_orig was formatted for logging: it was not the original address
at all, but rather was the address escaped for logging and possibly
replaced with "[scrubbed]".
This new logic will correctly set ADDRMAPSRC_NONE in the case when the
address starts life as a .exit address, so that AllowDotExit can work
again.
Fixes bug 6211; bugfix on 0.2.3.17-beta
It turns out this can happen. Even though there is no reason for
connections to be marked but reading, we leave them reading anyway,
so warning here is unwarranted. Let's turn that back on once we do
something sensible and disable reading when we mark. Bugfix for
6203 on Tor 0.2.3.17-beta.
Thanks to cypherpunks for pointing out the general stupidity of the
original code here.
On some platforms, the linker is perfectly happy to produce binaries
that won't run if you give it the wrong set of flags. So when not
cross-compiling, try to link-and-run a little test program, rather
than just linking it.
Possible fix for 6173.
Previously, a directory would check the latest NS consensus for
having the signatures the client wanted, and use that consensus's
valid_until time to set the HTTP lifetime. With this patch, the
directory looks at NS consensus or the microdesc consensus,
depending on what the client asked for.
The warning message of validate_pluggable_transports_config() is
superseded by the changes in the warning message of
connection_or_connect() when the proxy credentials can't be found.
This is a feature removal: we no longer fake any ciphersuite other
than the not-really-standard SSL_RSA_FIPS_WITH_3DES_EDE_CBC_SHA
(0xfeff). This change will let servers rely on our actually
supporting what we claim to support, and thereby let Tor migrate to
better TLS ciphersuites.
As a drawback, Tor instances that use old openssl versions and
openssl builds with ciphers disabled will no longer give the
"firefox" cipher list.
Manually removed range 0.116.0.0 to 0.119.255.255 which Maxmind says is
assigned to AT. This is very likely a bug in their database, because
0.0.0.0/8 is a reserved range.
From what I can tell, this configuration is usually a mistake, and
leads people to think that all their traffic is getting proxied when
in fact practically none of it is. Resolves the issue behind "bug"
4663.
The function is not guaranteed to NUL-terminate its output. It
*is*, however, guaranteed not to generate more than two bytes per
multibyte character (plus terminating nul), so the general approach
I'm taking is to try to allocate enough space, AND to manually add a
NUL at the end of each buffer just in case I screwed up the "enough
space" thing.
Fixes bug 5909.
This feature can make Tor relays less identifiable by their use of the
mod_ssl DH group, but at the cost of some usability (#4721) and bridge
tracing (#6087) regressions.
We should try to turn this on by default again if we find that the
mod_ssl group is uncommon and/or we move to a different DH group size
(see #6088). Before we can do so, we need a fix for bugs #6087 and
Resolves ticket #5598 for now.
These stats are currently discarded, but we might as well
hard-disable them on bridges, to be clean.
Fix for bug 5824; bugfix on 0.2.1.17-rc.
Patch originally by Karsten Loesing.
This code shouldn't have any effect in 0.2.3, since we already accept
(and handle) data received while we are expecting a renegotiation.
(That's because the 0.2.3.x handshake _does_ have data there instead of
the renegotiation.)
I'm leaving it in anyway, since if it breaks anything, we'll want it
broken in master too so we can find out about it. I added an XXX023
comment so that we can come back later and fix that.
This fixes a DoS issue where a client could send so much data in 5
minutes that they exhausted the server's RAM. Fix for bug 5934 and
6007. Bugfix on 0.2.0.20-rc, which enabled the v2 handshake.
It appears that when OpenSSL negotiates a 1.1 or 1.2 connection, and it
decides to renegotiate, the client will send a record with version "1.0"
rather than with the current TLS version. This would cause the
connection to fail whenever both sides had OpenSSL 1.0.1, and the v2 Tor
handshake was in use.
As a workaround, disable TLS 1.1 and TLS 1.2. When a later version of
OpenSSL is released, we can make this conditional on running a fixed
version of OpenSSL.
Alternatively, we could disable TLS 1.1 and TLS 1.2 only on the client
side. But doing it this way for now means that we not only fix TLS with
patched clients; we also fix TLS when the server has this patch and the
client does not. That could be important to keep the network running
well.
Fixes bug 6033.
Conflicts:
src/test/test_util.c
Merge the unit tests; I added some when I did this branch against
0.2.2, and then the test format changed and master added more tests.
Conflicts:
src/common/compat.h
Conflict was between replacement of MS_WINDOWS with _WIN32 in
master, and with removal of file_handle from tor_mmap_t struct in
close_file_mapping branch (for bug 5951 fix).
It turns out that if you set the third argument of
__attribute__(format) to 0, GCC and Clang will check the format
argument without expecting to find variadic arguments. This is the
correct behavior for vsnprintf, vasprintf, and vscanf.
I'm hoping this will fix bug 5969 (a clang warning) by telling clang that
the format argument to tor_vasprintf is indeed a format string.
On Windows, getsockname() on a nonblocking apparently won't work
until the connection is done connecting. On XP, it seems to fail by
reporting success and declaring that your address is INADDR_ANY. On the
Win8 preview, though, it fails more loudly and says WSAEINVAL.
Fix for bug 5374; bugfix on 0.1.1.14-alpha.
The parent of "/foo" is "/"; and "/" is its own parent.
This would cause Tor to fail if you tried to have a PF_UNIX control
socket in the root directory. That would be a stupid thing to do
for other reasons, but there's no reason to fail like _this_.
Bug found by Esteban Manchado Velázquez. Fix for bug 5089; bugfix on
Tor 0.2.2.26-beta. Unit test included.
Roger explains at
http://archives.seul.org/tor/talk/Nov-2011/msg00209.html :
"If you list your bridge as part of your family in the relay
descriptor, then everybody can learn your bridge fingerprint, and
they can look up your bridge's descriptor (and thus location) at
the bridge directory authority."
Now, we can't stop relays from listing bridges, but we can warn when
we notice a bridge listing anybody, which might help some.
This fixes bug 4657; it's a fix on 0.2.0.3-alpha, where bridges were
first introduced.
To hit this leak, you need to be a relay that gets a RESOLVE request
or an exit node getting a BEGIN or RESOLVE request. You must either
have unconfigured (and unconfigurable) nameservers, or you must have
somehow set DisableNetwork after a network request arrived but
before you managed to process it.
So, I doubt this is reached often. Still, a leak's a leak. Fix for
bug 5916; bugfix on 0.2.3.9-alpha and 0.1.2.1-alpha.
%f is correct; %lf is only needed with scanf. Apparently, on some
old BSDs, %lf is deprecated.
Didn't we do this before? Yes, we did. But we only got the
instances of %lf, not more complicated things like %.5lf . This
patch tries to get everything.
Based on a patch for 3894 by grarpamp.
These errors usually mean address exhaustion; reporting them as such
lets clients adjust their load to try other exits.
Fix for bug 4710; bugfix on 0.1.0.1-rc, which started using
END_STREAM_REASON_RESOURCELIMIT.
Previously, we only did this check at startup, which could lead to
us holding a guard indefinitely, and give weird results. Fixes bug
5380; bugfix on 0.2.1.14-rc.
(Patch by Roger; changes file and commit message by Nick)
Previously, we skipped everything that got invoked from
options_init_from_torrc. But some of the stuff in
options_act_reversible and options_act is actually important, like
reopening the logs.
Now, a SIGHUP always makes the effects of an options_set() happen,
even though the options haven't changed.
Fix for bug 5095; bugfix on 0.2.1.9-alpha, which introduced
__ReloadTorrcOnSIGHUP.
This would happen if the deliver window could become negative
because of an nonexistent connection. (Fortunately, _that_ can't
occur, thanks to circuit_consider_sending_sendme. Still, if we
change our windowing logic at all, we won't want this to become
triggerable.) Fix for bug 5541. Bugfix on 4a66865d, back from
0.0.2pre14. asn found this. Nice catch, asn!
We've been only treating SW_SERVER_HELLO_A as meaning that an SSL
handshake was happening. But that's not right: if the initial
attempt to write a ServerHello fails, we would get a callback in
state SW_SERVER_HELLO_B instead.
(That's "instead" and not "in addition": any failed attempt to write
the hello will fail and cause the info callback not to get written.)
Fix for bug 4592; bugfix on 0.2.0.13-alpha.
This tells the windows headers to give us definitions that didn't
exist before XP -- like the ones that we need for IPv6 support.
See bug #5861. We didn't run into this issue with mingw, since
mingw doesn't respect _WIN32_WINNT as well as it should for some of
its definitions.
Instead, allow packagers to put a 'TOR_BUILD_TAG' field in the
server descriptor to indicate a platform-specific value, if they
need to. (According to weasel, this was his use for the git- tag
previously.)
This is part of 2988
For uname-based detection, we now give only the OS name (e.g.,
"Darwin", "Linux".) For Windows, we give only the Operating System
name as inferred from dw(Major|Minor)version, (e.g., "Windows XP",
"Windows 7"), and whether the VER_NT_SERVER flag is set.
For ticket 2988.
This time, I follow grarpamp's suggestion and move the check for
.exit+AllowDotExit 0 to the top of connection_ap_rewrite_and_attach,
before any rewriting occurs. This way, .exit addresses are
forbidden as they arrive from a socks connection or a DNSPort
request, and not otherwise.
It _is_ a little more complicated than that, though. We need to
treat any .exit addresses whose source is TrackHostExits as meaning
that we can retry without that exit. We also need to treat any
.exit address that comes from an AutomapHostsOnResolve operation as
user-provided (and thus forbidden if AllowDotExits==0), so that
transitioning from AllowDotExits==1 to AllowDotExits==0 will
actually turn off automapped .exit addresses.
This patch changes the total serverdesc threshold from 25% to 75%
and the exit threshold from 33% to 50%. The goal is to make
initially constructed circuits less horrible, and to make initial
less awful (since fetching directory information in parallel with
whatever the user is trying to do can hurt their performance).
Implements ticket 3196.
We were doing an O(n) strlen in router_get_extrainfo_hash() for
every one we tried to parse. Instead, have
router_get_extrainfo_hash() take the length of the extrainfo as an
argument, so that when it's called from
extrainfo_parse_from_string(), it doesn't do a strlen() over the
whole pile of extrainfos.
If the authorities agreed on a sufficiently bad bwweightscale value
(<=0 or == INT32_MAX), the bandwidth algorithm could make the voters
assert while computing the consensus.
Fix for bug5786; bugfix on 0.2.2.17-alpha
The underlying strtoX functions handle overflow by saturating and
setting errno to ERANGE. If the min/max arguments to the
tor_parse_* functions are equal to the minimum/maximum of the
underlying type, then with the old approach, we wouldn't treat a
too-large value as genuinely broken.
Found this while looking at bug 5786; bugfix on 19da1f36 (in Tor
0.0.9), which introduced these functions.
We had been checking for EINVAL, but that means that SOCK_* isn't
supported, not that the syscall itself is missing.
Bugfix on 0.2.3.1-alpha, which started to use accept4.
We'd had our configure.in test include unistd.h unconditionally,
which would fail on Windows/mingw, even though environ _was_
declared there. Fix for 5704; bugfix on 0.2.3.13-alpha.
Thanks to Erinn for finding this and rransom for figuring out the
problem.
If the client uses a v2 cipherlist on the renegotiation handshake,
it looks as if they could fail to get a good cert chain from the
server, since they server would re-disable certificate chaining.
This patch makes it so the code that make the server side of the
first v2 handshake special can get called only once.
Fix for 4591; bugfix on 0.2.0.20-rc.
They boil down to:
- MS_WINDOWS is dead and replaced with _WIN32, but we let a few
instances creep in when we merged Esteban's tests.
- Capitalizing windows header names confuses mingw.
- #ifdef 0 ain't C.
- One unit test wasn't compiled on windows, but was being listed
anyway.
- One unit test was checking for the wrong value.
Gisle Vanem found and fixed the latter 3 issues.
Fixes bug #4528 "read_to_buf_tls(): Inconsistency in code".
This check was added back in 0.1.0.3-rc, but somehow we forgot to
leave it in when we refactored read_to_buf_tls in 0.1.0.5-rc.
(patch by Arturo; commit message and changes file by nickm)
Previously, we would reset it at the drop of a hat -- every time a second
passes without any of the intro-point circs already launched for the
service failing.
Fixes bug 4607.
This is just refactoring work here. The old logic was kind of
convoluted, especially after the bug 5572 fix. We don't actually need to
distinguish so many cases here. Dropping detection of the
"!old_options || !old_options->DynamicDHGroups" case is fine because
that's the same that we'd do for clients.
Also add a changes file for bug 5572.
The message only means that we're publishing a new descriptor when we
are actually in some kind of server mode, and publication is on.
Fix for bug 3942; bugfix on 0.2.3.2-alpha.
This fixes a side-channel attack on the (fortunately unused!)
BridgePassword option for bridge authorities. Fix for bug 5543;
bugfix on 0.2.0.14-alpha.
This is ticket 2479. Roger's original explanation was:
We have a series of bugs where relays publish a descriptor within
12 hours of their last descriptor, but the authorities drop it
because it's not different "enough" from the last one and it's
too close to the last one.
The original goal of this idea was to a) reduce the number of new
descriptors authorities accept (and thus have to store) and b)
reduce the total number of descriptors that clients and mirrors
fetch. It's a defense against bugs where relays publish a new
descriptor every minute.
Now that we're putting out one consensus per hour, we're doing
better at the total damage that can be caused by 'b'.
There are broader-scale design changes that would help here, and
we've had a trac entry open for years about how relays should
recognize that they're not in the consensus, or recognize when
their publish failed, and republish sooner.
In the mean time, I think we should change some of the parameters
to make the problem less painful.
When we started RefuseUnknownExits back in 0.2.2.11-alpha, we
started making exits act like they cache directory info (since they
need an up-to-date idea of who is really a router). But this
included fetching needless (unrecognized) authorities' certs, which
doesn't make any sense for them.
This is related to, but not necessarily the same as, the issue that
Ian reported for bug #2297.
(This patch is based on a patch from a user who I believe has asked
not to be named. If I'm wrong about that, please add the
appropriate name onto the changelog.)
==
Nick here. I tweaked this patch a little to make it apply cleanly to
master, to extract some common code into a function, and to replace
snprintf with tor_snprintf.
-- nickm
Specifically, it was a fix on 33e2053ebc, where we introduced the
WRA_* and ROUTER_* codes for dirserv_add_descriptor. Previously, we
had checked for a _negative_ return from dirserv_add_descriptor, which
meant "rejected". An insufficiently new descriptor would give a
0-valued return. But when we switched from numbers to enums, we got
this check wrong and had init_keys() give an error whenever the
descriptor wasn't accepted.
This mitigates an attack proposed by wanoskarnet, in which all of a
client's bridges collude to restrict the exit nodes that the client
knows about. Fixes bug 5343.
Since 0.2.3.1-alpha, we've supported the Linux extensions to socket(),
open(), socketpair(), and accept() that enable us to create an fd and
make it close-on-exec with a single syscall. This not only saves us a
syscall (big deal), but makes us less vulnerable to race conditions
where we open a socket and then exec before we can make it
close-on-exec.
But these extensions are not supported on all Linuxes: They were added
between 2.6.23 or so and 2.6.28 or so. If you were to build your Tor
against a recent Linux's kernel headers, and then run it with a older
kernel, you would find yourselve unable to open sockets. Ouch!
The solution here is that, when one of these syscalls fails with
EINVAL, we should try again in the portable way. This adds an extra
syscall in the case where we built with new headers and are running
with old ones, but it will at least allow Tor to work.
Fixes bug 5112; bugfix on 0.2.3.1-alpha.
The big change here is a patch (first added to Libevent by Ed Day)
to make sure that the CreateProcess forked-test trick works even
when the main test program is invoked without its .exe suffix.
Previously we'd been using "we have clock_gettime()" as a proxy for
"we need -lrt to link a static libevent". But that's not really
accurate: we should only add -lrt if searching for clock_gettime
function adds -lrt to our libraries.
in Makefile.am, we used it without quoting it, causing build failure if
your openssl/sed/sha1sum happened to live in a directory with a space in
it (very common on windows)
This reverts commit 55e8cae815.
The conversation from irc:
> weasel: i had intended to leave torrc.sample.in alone in maint-0.2.2,
since i don't want to make all your stable users have to deal with
a torrc change. but nickm changed it. is it in fact the case that a
change in that file means a change in the deb?
<weasel> it means you'll prompt every single user who ever touched
their torrc
<weasel> and they will be asked if they like your new version better
than what they have right now
<weasel> so it's not great
Instead I changed the website to redirect requests for the tor-manual
URL listed in maint-0.2.2's torrc.sample.in so the link will still work.
If we don't do this, [::] can be interpreted to mean all v4 and all
v6 addresses. Found by dcf. Fixes bug 4760. See RFC 3493 section
5.3 for more info.
There was one MS_WINDOWS that remained because it wasn't on a macro
line; a few remaining uses (and the definition!) in configure.in;
and a now-nonsensical stanza of eventdns_tor.h that previously
defined 'WIN32' if it didn't exist.
