Simon Tatham [Tue, 7 Apr 2015 20:54:41 +0000 (21:54 +0100)]
Clean up a stale foreign handle in winnps.c.
I had set up an event object for signalling incoming connections to
the named pipe, and then called handle_add_foreign_event to get that
event object watched for connections - but when I closed down the
listening pipe, I deleted the event object without also cancelling
that foreign-event handle, so that winhandl.c would potentially call
the callback for a destroyed object.
Simon Tatham [Sat, 7 Mar 2015 20:57:26 +0000 (20:57 +0000)]
Don't output negative numbers in the ESC[13t report.
A minus sign is illegal at that position in a control sequence, so if
ESC[13t should report something like ESC[3;-123;234t then we won't
accept it as input. Switch to printing the numbers as unsigned, so
that negative window coordinates are output as their 32-bit two's
complement; experimentation suggests that PuTTY does accept that on
input.
Simon Tatham [Sat, 7 Mar 2015 17:10:36 +0000 (17:10 +0000)]
Stop Windows PuTTY becoming unresponsive if server floods us.
This was an old bug, fixed around 0.59, which apparently regressed
when I rewrote the main event loop using the toplevel_callback
mechanism.
Investigation just now suggests that it has to do with my faulty
assumption that Windows PeekMessage would deliver messages in its
message queue in FIFO order (i.e. that the thing calling itself a
message queue is actually a _queue_). In fact my WM_NETEVENT seems to
like to jump the queue, so that once a steady stream of them starts
arriving, we never do anything else in the main event loop (except
deal with handles).
Worked around in a simple and slightly bodgy way, namely, we don't
stop looping on PeekMessage and run our toplevel callbacks until we've
either run out of messages completely or else seen at least one that
_isn't_ a WM_NETEVENT. That way we should reliably interleave NETEVENT
processing with processing of other stuff.
Simon Tatham [Sat, 28 Feb 2015 12:04:54 +0000 (12:04 +0000)]
Reorganise the release checklist.
Mostly I'm rearranging things because of the new workflows that git
makes available - it's now possible (and indeed sensible) to prepare a
lot of stuff in a fairly relaxed manner in local checkouts, and then
the process of going live with the release has a lot less manual
writing of stuff and a lot more mechanical 'git push' and running of
update scripts.
However, there's one new item that was actually missed off the
previous checklist: turning off nightly pre-release builds after
making the release they were a pre-release of. Ahem.
Simon Tatham [Sat, 28 Feb 2015 07:58:29 +0000 (07:58 +0000)]
New 'contrib' tool: a script for faking initial KEX.
encodelib.py is a Python library which implements some handy SSH-2
encoding primitives; samplekex.py uses that to fabricate the start of
an SSH connection, up to the point where key exchange totally fails
its crypto.
The idea is that you adapt samplekex.py to construct initial-kex
sequences with particular properties, in order to test robustness and
security fixes that affect the initial-kex sequence. For example, I
used an adaptation of this to test the Diffie-Hellman range check
that's just gone into 0.64.
Simon Tatham [Thu, 19 Feb 2015 20:08:18 +0000 (20:08 +0000)]
Add some missing smemclrs and sfrees.
The absence of these could have prevented sensitive private key
information from being properly cleared out of memory that PuTTY tools
had finished with.
Thanks to Patrick Coleman for spotting this and sending a patch.
Simon Tatham [Thu, 5 Feb 2015 19:39:17 +0000 (19:39 +0000)]
Enforce acceptable range for Diffie-Hellman server value.
Florent Daigniere of Matta points out that RFC 4253 actually
_requires_ us to refuse to accept out-of-range values, though it isn't
completely clear to me why this should be a MUST on the receiving end.
Matta considers this to be a security vulnerability, on the grounds
that if a server should accidentally send an obviously useless value
such as 1 then we will fail to reject it and agree a key that an
eavesdropper could also figure out. Their id for this vulnerability is
MATTA-2015-002.
Jacob Nevins [Tue, 24 Feb 2015 10:30:18 +0000 (10:30 +0000)]
Make kh2reg.py compatible with modern Python.
Bare string exceptions aren't supported any more.
Patch by Will Aoki, plus a backward compatibility tweak from Colin Watson.
Seen working with Python 2.4.3 and 2.7.6.
Simon Tatham [Sat, 7 Feb 2015 11:48:49 +0000 (11:48 +0000)]
Improve comments in winhandl.c.
To understand the handle leak bug that I fixed in git commit 7549f2da40d3666f2c9527d84d9ed5468e231691, I had to think fairly hard
to remind myself what all this code was doing, which means the
comments weren't good enough. Expanded and rewritten some of them in
the hope that things will be clearer next time.
Simon Tatham [Sat, 7 Feb 2015 12:39:47 +0000 (12:39 +0000)]
Mark handles defunct before calling gotdata/sentdata.
If (say) a read handle returns EOF, and its gotdata function responds
by calling handle_free(), then we want the handle to have already had
its defunct flag set so that the handle can be destroyed. Otherwise
handle_free will set the 'done' flag to ask the subthread to
terminate, and then sit and wait for it to say it's done so -
forgetting that it signalled termination already by returning EOF, and
hence will not be responding to that signal.
Ditto for write errors on write handles, though that should happen
less often.
Simon Tatham [Sat, 7 Feb 2015 11:48:19 +0000 (11:48 +0000)]
Fix handle leak in winhandl.c.
The code for cleaning up handle structures works by the main thread
asking the per-handle subthread to shut down by means of setting its
'done' flag, and then once the subthread signals back through its
event object that it's done so, the main thread frees all its
resources and removes the event object from the list of things being
checked in the program's event loop.
But read threads were not sending back that final event acknowledging
a request to shut down, so their event objects were never being
cleaned up.
Jacob Nevins [Sun, 18 Jan 2015 14:44:45 +0000 (14:44 +0000)]
Remove user-key-oriented advice from host key docs.
It would be rare to have a host keypair in .ppk format or on a client
machine to load into PuTTYgen, and it might confuse people into thinking
they are required to do so.
Jacob Nevins [Mon, 5 Jan 2015 23:41:43 +0000 (23:41 +0000)]
Use local username consistently in Unix Plink.
It tries to use the local username as the remote username if it has no
better ideas, but the presence of Default Settings would defeat this,
even if it had no username set. Reported by Jonathan Amery.
Simon Tatham [Sat, 20 Dec 2014 18:43:46 +0000 (18:43 +0000)]
Fix memory management in bignum_random_in_range.
We were allocating a new array in which to make up a random number
every time we went round the loop, and not freeing any of them. Now we
allocate a single array to use for all loop iterations, and clear and
free it properly afterwards.
Simon Tatham [Sat, 20 Dec 2014 18:42:22 +0000 (18:42 +0000)]
Fix a handle leak in Windows PSFTP.
We were checking the return value of CreateThread for validity, but
not keeping it to free afterwards if it _was_ valid. Also, we weren't
closing ctx->event in the valid case either. Patch due to Tim Kosse.
Simon Tatham [Sat, 20 Dec 2014 17:07:17 +0000 (17:07 +0000)]
Fixes to memory management in the elliptic curve code.
There was an error-handling path testing the wrong variable; an
inappropriate call to ec_point_free in decodepoint() (in fact, that
function always gets passed a pointer to an ec_point structure that's
not a dynamically allocated block at all or not in its own right, so
we should have just cleared its contents without freeing the structure
itself); a missing return on an error path which would have caused the
same structure to be freed a second time; and two missing freebn in
ecdsa_sign.
Simon Tatham [Sat, 20 Dec 2014 16:54:28 +0000 (16:54 +0000)]
Add a missing freeaddrinfo() in Unix sk_newlistener.
If we use getaddrinfo to translate the source IP address into a
sockaddr, then we need to freeaddrinfo the returned data later. Patch
due to Tim Kosse.
Simon Tatham [Sat, 22 Nov 2014 16:38:01 +0000 (16:38 +0000)]
Stop referring to Plink as "PuTTY Link".
I don't think anyone has ever actually called it that, colloquially
_or_ formally, and if anyone ever did (in a bug report, say) I'd
probably have to stop and think to work out what they meant. It's
universally called Plink, and should be officially so as well :-)
Simon Tatham [Sat, 22 Nov 2014 16:35:54 +0000 (16:35 +0000)]
Another missing initialisation.
This one spotted in the old-fashioned way, by actually attempting a
Plink raw connection and wondering why it didn't seem to be reading
from standard input! Turns out 'bufsize' is uninitialised until the
first send, which can inhibit any stdin reading if it gets a large
enough nonsense value.
Simon Tatham [Sat, 22 Nov 2014 16:30:29 +0000 (16:30 +0000)]
Consistently use &def for %makefile_extra pieces.
mkfiles.pl was giving a couple of annoying perl warnings, because some
makefile_extra strings were never set by Recipe. We already have the
&def function to convert undefs into "" for this reason, but weren't
using it everywhere. Now I think we are.
Simon Tatham [Sat, 22 Nov 2014 16:12:47 +0000 (16:12 +0000)]
Move echo/edit state change functionality out of ldisc_send.
I'm not actually sure why we've always had back ends notify ldisc of
changes to echo/edit settings by giving ldisc_send(ldisc,NULL,0,0) a
special meaning, instead of by having a separate dedicated notify
function with its own prototype and parameter set. Coverity's recent
observation that the two kinds of call don't even have the same
requirements on the ldisc (particularly, whether ldisc->term can be
NULL) makes me realise that it's really high time I separated the two
conceptually different operations into actually different functions.
While I'm here, I've renamed the confusing ldisc_update() function
which that special operation ends up feeding to, because it's not
actually a function applying to an ldisc - it applies to a front end.
So ldisc_send(ldisc,NULL,0,0) is now ldisc_echoedit_update(ldisc), and
that in turn figures out the current echo/edit settings before passing
them on to frontend_echoedit_update(). I think that should be clearer.
Simon Tatham [Sat, 22 Nov 2014 10:18:16 +0000 (10:18 +0000)]
Fix uninitialised variable in two Windows event loops.
If (Msg)WaitForMultipleObjects returns WAIT_TIMEOUT, we expect 'next'
to have been initialised. This can occur without having called
run_timers(), if a toplevel callback was pending, so we can't expect
run_timers to have reliably initialised 'next'.
I'm not actually convinced this could have come up in either of the
affected programs (Windows PSFTP and Plink), due to the list of things
toplevel callbacks are currently used for, but it certainly wants
fixing anyway for the future.
Simon Tatham [Sat, 22 Nov 2014 10:37:14 +0000 (10:37 +0000)]
Clarify when ldisc->term may be NULL.
Namely, any ldisc that you send actual data through should have a
terminal attached, because the ldisc editing/echoing system is
designed entirely for use with a terminal. The only time you can have
an ldisc with no terminal is when it's only ever used by the backend
to report changes to the front end in edit/echo status, e.g. by Unix
Plink.
Coverity spotted an oddity in ldisc_send which after a while I decided
would never have actually caused a problem, but OTOH I agree that it
was confusing, so now hopefully it's less so.
Simon Tatham [Sat, 22 Nov 2014 10:12:47 +0000 (10:12 +0000)]
Fix typo in validate_manual_hostkey().
'p += strcspn' returns p always non-NULL and sometimes pointing at \0,
as opposed to 'p = strchr' which returns p sometimes non-NULL and
never pointing at \0. Test the pointer after the call accordingly.
Thanks, Coverity.
Simon Tatham [Mon, 10 Nov 2014 18:29:00 +0000 (18:29 +0000)]
Shut down connshare upstream along with the SSH connection.
This ought to happen in ssh_do_close alongside the code that shuts
down other local listening things like port forwardings, for the same
obvious reason. In particular, we should get through this _before_ we
put up a modal dialog box telling the user what just went wrong with
the SSH connection, so that further sessions started while that box is
active don't try futilely to connect to the not-really-listening
zombie upstream.
Jacob Nevins [Sun, 9 Nov 2014 00:08:36 +0000 (00:08 +0000)]
Disable manual host key config in mid-session.
Changing it can't have any useful effect, since we have strictly
enforced that the host key used for rekeys is the same as the first key
exchange since b8e668c.
Simon Tatham [Sat, 1 Nov 2014 19:33:29 +0000 (19:33 +0000)]
Fix details of the Pageant and PuTTYgen GUIs for ECDSA.
Pageant's list box needs its tab stops reorganised a little for new
tendencies in string length, and also has to cope with there only
being one prefix space in the output of the new string fingerprint
function. PuTTYgen needs to squash more radio buttons on to one line.
Chris Staite [Sat, 1 Nov 2014 09:45:20 +0000 (09:45 +0000)]
Elliptic-curve cryptography support.
This provides support for ECDSA public keys, for both hosts and users,
and also ECDH key exchange. Supported curves are currently just the
three NIST curves required by RFC 5656.
Chris Staite [Sat, 1 Nov 2014 08:59:25 +0000 (08:59 +0000)]
Provide SHA-384 and SHA-512 as hashes usable in SSH KEX.
SHA-384 was previously not implemented at all, but is a trivial
adjustment to SHA-512 (different starting constants, and truncate the
output hash). Both are now exposed as 'ssh_hash' structures so that
key exchange methods can ask for them.
Chris Staite [Sat, 1 Nov 2014 09:14:19 +0000 (09:14 +0000)]
Refactoring to prepare for extra public key types.
The OpenSSH key importer and exporter were structured in the
assumption that the strong commonality of format between OpenSSH RSA
and DSA keys would persist across all key types. Moved code around so
it's now clear that this is a peculiarity of those _particular_ two
key types which will not apply to others we add alongside them.
Also, a boolean 'is_dsa' in winpgen.c has been converted into a more
sensible key type enumeration, and the individually typed key pointers
have been piled on top of each other in a union.
This is a pure refactoring change which should have no functional
effect.
Simon Tatham [Sat, 1 Nov 2014 19:48:48 +0000 (19:48 +0000)]
Factor out the DSA deterministic k generator.
It's now a separate function, which you call with an identifying
string to be hashed into the generation of x. The idea is that other
DSA-like signature algorithms can reuse the same function, with a
different id string.
As a minor refinement, we now also never return k=1.
Simon Tatham [Tue, 28 Oct 2014 18:39:55 +0000 (18:39 +0000)]
Fix two double-frees in ssh2_load_userkey().
We should NULL out mac after freeing it, so that the cleanup code
doesn't try to free it again; also if the final key creation fails, we
should avoid freeing ret->comment when we're going to go to that same
cleanup code which will free 'comment' which contains the same pointer.
Thanks to Christopher Staite for pointing these out.
Simon Tatham [Wed, 1 Oct 2014 18:33:45 +0000 (18:33 +0000)]
Add a missing bounds check in the Deflate decompressor.
The symbol alphabet used for encoding ranges of backward distances in
a Deflate compressed block contains 32 symbol values, but two of them
(symbols 30 and 31) have no meaning, and hence it is an encoding error
for them to appear in a compressed block. If a compressed file did so
anyway, this decompressor would index past the end of the distcodes[]
array. Oops.
This is clearly a bug, but I don't believe it's a vulnerability. The
nonsense record we load from distcodes[] in this situation contains an
indeterminate bogus value for 'extrabits' (how many more bits to read
from the input stream to complete the backward distance) and also for
the offset to add to the backward distance after that. But neither of
these can lead to a buffer overflow: if extrabits is so big that
dctx->nbits (which is capped at 32) never exceeds it, then the
decompressor will simply swallow all further data without producing
any output, and otherwise the decompressor will consume _some_ number
of spare bits from the input, work out a backward distance and an
offset in the sliding window which will be utter nonsense and probably
out of bounds, but fortunately will then AND the offset with 0x7FFF at
the last minute, which makes it safe again. So I think the worst that
a malicious compressor can do is to cause the decompressor to generate
strange data, which of course it could do anyway if it wanted to by
sending that same data legally compressed.
Simon Tatham [Wed, 24 Sep 2014 10:33:13 +0000 (10:33 +0000)]
Rework versioning system to not depend on Subversion.
I've shifted away from using the SVN revision number as a monotonic
version identifier (replacing it in the Windows version resource with
a count of days since an arbitrary epoch), and I've removed all uses
of SVN keyword expansion (replacing them with version information
written out by Buildscr).
While I'm at it, I've done a major rewrite of the affected code which
centralises all the computation of the assorted version numbers and
strings into Buildscr, so that they're all more or less alongside each
other rather than scattered across multiple source files.
I've also retired the MD5-based manifest file system. A long time ago,
it seemed like a good idea to arrange that binaries of PuTTY would
automatically cease to identify themselves as a particular upstream
version number if any changes were made to the source code, so that if
someone made a local tweak and distributed the result then I wouldn't
get blamed for the results. Since then I've decided the whole idea is
more trouble than it's worth, so now distribution tarballs will have
version information baked in and people can just cope with that.
Simon Tatham [Tue, 23 Sep 2014 12:38:16 +0000 (12:38 +0000)]
Bodge around the failing Coverity build in winshare.c.
The winegcc hack I use for my Coverity builds is currently using a
version of wincrypt.h that's missing a couple of constants I use.
Ensure they're defined by hand, but (just in case I defined them
_wrong_) also provide a command-line define so I can do that only in
the case of Coverity builds.