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Commit Graph

583 Commits

Author SHA1 Message Date
Simon Tatham
ac8baf4cac Move the SSH-1 servkey and hostkey variables into the coroutine state,
since there is a theoretical code path (via the crReturn loop after
asking an interactive question about a host key or crypto algorithm)
on which we can leave and return to do_ssh1_login between allocating
and freeing those keys.

(In practice it shouldn't come up anyway with any of the current
implementations of the interactive question functions, not to mention
the unlikelihood of anyone non-specialist still using SSH-1, but
better safe than sorry.)

[originally from svn r9895]
2013-07-07 14:34:37 +00:00
Simon Tatham
bbc9709b48 A collection of small bug fixes from Chris West, apparently spotted by
Coverity: assorted language-use goofs like freeing the wrong thing or
forgetting to initialise a string on all code paths.

[originally from svn r9889]
2013-07-01 17:56:33 +00:00
Ben Harris
8f3cc4a9bf Add support for HMAC-SHA-256 as an SSH-2 MAC algorithm ("hmac-sha2-256")
as specified in RFC 6668.  This is not so much because I think it's 
necessary, but because scrypt uses HMAC-SHA-256 and once we've got it we 
may as well use it.

Code very closely derived from the HMAC-SHA-1 code.

Tested against OpenSSH 5.9p1 Debian-5ubuntu1.

[originally from svn r9759]
2013-02-20 23:30:55 +00:00
Ben Harris
bc8f2193f6 Allow remote-to-local forwardings to use IPv6.
RFC 4245 section 7.1 specifies the meaning of the "address to bind"
parameter in a "tcpip-forward" request.  "0.0.0.0" and "127.0.0.1" are
specified to be all interfaces and the loopback interface respectively
in IPv4, while "" and "localhost" are the address-family-agnostic
equivalents.  Switch PuTTY to using the latter, since it doesn't seem
right to force IPv4.

There's an argument that PuTTY should provide a means of configuring the
address family used for remote forwardings like it does for local ones.

[originally from svn r9668]
2012-09-18 21:50:47 +00:00
Ben Harris
d5836982e2 Two related changes to timing code:
First, make absolute times unsigned.  This means that it's safe to 
depend on their overflow behaviour (which is undefined for signed 
integers).  This requires a little extra care in handling comparisons, 
but I think I've correctly adjusted them all.

Second, functions registered with schedule_timer() are guaranteed to be 
called with precisely the time that was returned by schedule_timer().  
Thus, it's only necessary to check these values for equality rather than 
doing risky range checks, so do that.

The timing code still does lots that's undefined, unnecessary, or just
wrong, but this is a good start.

[originally from svn r9667]
2012-09-18 21:42:48 +00:00
Ben Harris
8c1d1be956 Most of the code for "nc" mode duplicated that for opening a session or
a fowarded port.  Arrange that this code is shared instead.  The main
visible change is a slight change of log messages.

[originally from svn r9655]
2012-09-08 19:46:07 +00:00
Simon Tatham
14539a7719 Hiroshi Oota points out that PuTTY's agent forwarding sockets can get
confused if they receive a request followed by immediate EOF, since we
currently send outgoing EOF as soon as we see the incoming one - and
then, when the response comes back from the real SSH agent, we send it
along anyway as channel data in spite of having sent EOF.

To fix this, I introduce a new field for each agent channel which
counts the number of calls to ssh_agentf_callback that are currently
expected, and we don't send EOF on an agent channel until we've both
received EOF and that value drops to zero.

[originally from svn r9651]
2012-09-08 10:40:36 +00:00
Ben Harris
33c58dd91b Factor out some common code for constructing SSH2_CHANNEL_OPEN.
[originally from svn r9649]
2012-09-01 12:28:38 +00:00
Ben Harris
de6d59b500 struct winadj is unused now. G/c it.
[originally from svn r9648]
2012-09-01 12:10:27 +00:00
Ben Harris
98e562b7f6 All of the initial CHANNEL_REQUESTs are conditional on (ssh->mainchan &&
!ssh->ncmode), so bundle them up in a big block conditional on this rather
than checking it five times.

[originally from svn r9647]
2012-09-01 12:03:12 +00:00
Ben Harris
54da9ee07a do_ssh2_authconn() now installs the standard handlers for CHANNEL_SUCCESS
and CHANNEL_FAILURE as soon as it's opened a channel, so there's no need
for it to set them again later.

[originally from svn r9646]
2012-09-01 11:32:53 +00:00
Simon Tatham
b631c1e18e Rename the various ssh2_maybe_setup_* functions to ssh2_setup_*, and
move the primary conditions out of them into their callers. Fixes a
crash in 'plink -N', since those functions would be called with a NULL
channel parameter and immediately dereference it to try to get c->ssh.

[originally from svn r9644]
2012-08-30 18:44:35 +00:00
Ben Harris
e27ce2017e Change return type of do_ssh2_transport() to void.
Nothing pays attention to it any more, anyway.

[originally from svn r9635]
2012-08-27 22:02:17 +00:00
Ben Harris
3cc03d85e7 Make bombout() less of a macro and more of a function.
This gives GCC slightly fewer opportunities to gratuitously inflate
its output.

[originally from svn r9634]
2012-08-27 21:55:45 +00:00
Ben Harris
df83634e21 Fix a memory leak in parse_ttymodes() (found by Memcheck/Valgrind).
[originally from svn r9633]
2012-08-27 19:11:39 +00:00
Ben Harris
475507e978 Slightly simplify crFinishFree{,V}.
They're only likely to be useful for freeing a coroutine state
structure, in which case there's no need to reset the line number
(since all such coroutines keep their line number in the state
structure) and the state structure pointer is always called "s".

[originally from svn r9632]
2012-08-27 18:44:06 +00:00
Ben Harris
0768c8557d Don't close SSH-2 channels with outstanding channel requests on local error.
In sshfwd_unclean_close(), get ssh2_check_close() to handle sending
SSH_MSG_CHANNEL_CLOSE.  That way, it can hold off doing so until any
outstanding channel requests are processed.

Also add event log message for unclean channel closures.

[originally from svn r9631]
2012-08-27 17:37:44 +00:00
Simon Tatham
3fa95b2a7f It's not legal to free a coroutine's state structure before invoking
crFinish or crFinishV, since they will attempt to write to the
coroutine state variable contained in that structure. Introduced some
new all-in-one macros crFinishFree and crFinishFreeV, and used those
instead. Should fix today's report of a crash just after authentication.

[originally from svn r9630]
2012-08-27 14:34:41 +00:00
Ben Harris
3d466aec90 Better handling of outstanding CHANNEL_REQUESTS on channel destruction.
Part the first: make sure that all structures describing channel
requests are freed when the SSH connection is freed.  This involves
adding a means to ask a response handler to free any memory it holds.

Part the second: in ssh_channel_try_eof(), call
ssh2_channel_check_close() rather than emitting an SSH_MSG_CHANNEL_EOF
directly.  This avoids the possibility of closing the channel while a
CHANNEL_REQUEST is outstanding.

Also add some assertions that helped with tracking down the latter
problem.

[originally from svn r9623]
2012-08-25 21:06:48 +00:00
Ben Harris
4e623f5b23 Factor out common code to construct CHANNEL_REQUESTS.
This reduces code size a little and also makes it harder to
accidentally request a reply without putting in place a handler for
it or vice versa.

[originally from svn r9620]
2012-08-25 15:57:05 +00:00
Ben Harris
ab6d966f91 Simplify handling of responses to channel requests.
The various setup routines can only receive CHANNEL_SUCCESS or
CHANNEL_FAILURE, so there's no need for the to worry about receiving
anything else.  Strange packets will end up in do_ssh2_authconn
instead.

[originally from svn r9619]
2012-08-25 15:04:29 +00:00
Ben Harris
30e43ba2a3 Handle all replies to CHANNEL_REQUESTs through the per-channel queue.
Each of the minor start-of-session requests is now dealt with by its own 
little co-routine, while the shell/command is done in do_ssh2_authconn() 
itself.  This eliminates one more round-trip in session setup: PuTTY gets
all the way up to sending a shell request before worrying about any
replies.

[originally from svn r9616]
2012-08-25 13:39:32 +00:00
Ben Harris
57945a753f Generalise SSH_MSG_CHANNEL_{SUCCESS,FAILURE} handling.
Now each channel has a queue of arbitrary handlers for those messages, 
with anything that sends a CHANNEL_REQUEST with want_reply true pushing 
a new entry onto the queue, and a shared handler that dispatches 
responses appropriately.

Currently, this is only used for winadj@putty.projects.tartarus.org, but 
extending it to cover the initial requests as well shouldn't be too 
painful.

[originally from svn r9615]
2012-08-25 11:12:14 +00:00
Ben Harris
f071feb9a6 Fix recently-introduced memory leak in ssh2_msg_unexpected().
[originally from svn r9611]
2012-08-21 23:04:22 +00:00
Ben Harris
e148dd97e3 De-duplicate code in KEXINIT generation.
There's no need to have identical code generating server-to-client and
client-to-server versions of the cipher and MAC lists; a couple of
twice-around loops will do fine.

[originally from svn r9610]
2012-08-21 22:33:31 +00:00
Ben Harris
8e0ab8be59 Reworking of packet delivery to coroutines in SSH-2.
Before, NULL in the dispatch table meant "send to the appropriate one of 
do_ssh2_transport() and do_ssh2_authconn()".  Now those (via small 
shims) are specified directly in the dispatch table, so ssh2_protocol() 
is much simpler.

In the process, this has somewhat centralised the handling of gross 
server protocol violations.  PuTTY will now disconnect with a rude 
message when (e.g.) OpenSSH sends us an SSH_MSG_UNIMPLEMENTED when we 
try to KEXINIT during authentication.

[originally from svn r9609]
2012-08-21 22:04:56 +00:00
Ben Harris
4e5012aeda Fix an erroneous "case" fallthrough in ssh1_msg_channel_close, which was
causing assertion failures when closing X11 channels in SSH-1.  Also fix 
another pasto.

[originally from svn r9608]
2012-08-19 11:35:26 +00:00
Ben Harris
e570820c74 Tweak to SSH coroutine code: put line number in the coroutine state
structure, which is consistent with Simon's canonical version of the
macros.

[originally from svn r9607]
2012-08-18 09:30:01 +00:00
Ben Harris
37ea0f4541 Reduce the number of round-trips involved in opening an SSH-2 session
by sending most of the initial SSH_MSG_CHANNEL_REQUEST messages before
waiting for any replies.  The initial version of this code was a clever
thing with a two-pass loop, but that got hairy so I went for the simpler
approach of separating the request and reply code and having flags to
keep track of which requests have been sent.

[originally from svn r9599]
2012-08-02 22:18:18 +00:00
Simon Tatham
71f0c7546d Add a bug-compatibility flag to disable the
winadj@putty.projects.tartarus.org request. Not currently enabled
automatically, but should be usable as a manual workaround.

[originally from svn r9592]
2012-07-28 19:30:12 +00:00
Simon Tatham
aa5bae8916 Introduce a new utility function smemclr(), which memsets things to
zero but does it in such a way that over-clever compilers hopefully
won't helpfully optimise the call away if you do it just before
freeing something or letting it go out of scope. Use this for
(hopefully) every memset whose job is to destroy sensitive data that
might otherwise be left lying around in the process's memory.

[originally from svn r9586]
2012-07-22 19:51:50 +00:00
Simon Tatham
a46aac386b Add missing check for failure to agree a host key algorithm.
[originally from svn r9557]
2012-06-04 23:32:36 +00:00
Simon Tatham
b73527e641 When we are asked to unthrottle an SSH connection (by the front end
calling back->unthrottle), we should immediately call
ssh_process_queued_incoming_data to handle the SSH packets that have
been saved for later functioning while we were throttled. Otherwise,
they'll sit there unhandled until the next call to ssh_gotdata, which
might not be for ages if the server thinks it's waiting for us.

[originally from svn r9523]
2012-05-12 17:00:54 +00:00
Simon Tatham
7c61b3c733 If we're called on to uncleanly close an SSH channel for which we've
already sent SSH2_MSG_CHANNEL_CLOSE, we should not skip the _whole_ of
sshfwd_unclean_close(), only the part about sending
SSH2_MSG_CHANNEL_CLOSE. It's still important to retag the SSH channel
as CHAN_ZOMBIE and clean up its previous data provider.

[originally from svn r9389]
2012-01-26 18:22:28 +00:00
Simon Tatham
49927f6c4d Introduce a function sshfwd_unclean_close(), supplied by ssh.c to
subsidiary network modules like portfwd.c. To be called when the
subsidiary module experiences a socket error: it sends an emergency
CHANNEL_CLOSE (not just outgoing CHANNEL_EOF), and immediately deletes
the local side of the channel. (I've invented a new channel type in
ssh.c called CHAN_ZOMBIE, for channels whose original local side has
already been thrown away and they're just hanging around waiting to
receive the acknowledging CHANNEL_CLOSE.)

As a result of this and the last few commits, I can now run a port
forwarding session in which a local socket error occurs on a forwarded
port, and PuTTY now handles it apparently correctly, closing both the
SSH channel and the local socket and then actually recognising that
it's OK to terminate when all _other_ channels have been closed.
Previously the channel corresponding to the duff connection would
linger around (because of net_pending_errors never being called), and
keep being selected on (hence chewing CPU), and inhibit program
termination at the end of the session (because not all channels were
closed).

[originally from svn r9364]
2011-12-08 19:15:58 +00:00
Simon Tatham
8aa218e894 When we receive CHANNEL_CLOSE on an SSH-2 channel and haven't sent EOF
on it yet, we should send EOF on _that channel_, not the main session
channel! Oops.

[originally from svn r9362]
2011-12-08 19:15:55 +00:00
Simon Tatham
69a01afe48 Whitespace fix while I was passing.
[originally from svn r9361]
2011-12-08 19:15:54 +00:00
Simon Tatham
8e9868bda0 Make sure we never send window adjustments (or winadjes) on channels
for which we've already sent CHANNEL_CLOSE. It would be embarrassing
if the remote end had also sent CHANNEL_CLOSE in response and then
received our communication once it had forgotten about the channel.

[originally from svn r9360]
2011-12-08 19:15:53 +00:00
Simon Tatham
bb542eaeff Add a missing free_prompts() call in the keyboard-interactive code.
[originally from svn r9357]
2011-12-07 19:07:02 +00:00
Simon Tatham
da66c0656a While I'm crusading against arbitrary limits, here's a redesign of
prompt_t to arrange that the buffer in which each prompt is stored can
be reallocated larger during the input process.

[originally from svn r9317]
2011-10-02 11:50:45 +00:00
Simon Tatham
62cbc7dc0b Turn 'Filename' into a dynamically allocated type with no arbitrary
length limit, just as I did to FontSpec yesterday.

[originally from svn r9316]
2011-10-02 11:01:57 +00:00
Simon Tatham
aac16a33e8 No, I take that back: we _do_ have a mechanism for suppressing reads
from forwarding data sources which will be good enough to last until
we close the socket, in the form of the override_throttle() functions.
So this finishes up the work in r9283, by manufacturing outgoing EOF
in response to incoming CLOSE on all channel types.

[originally from svn r9284]
[r9283 == c54e228d04]
2011-09-14 09:49:00 +00:00
Simon Tatham
c54e228d04 Another tweak to EOF policy: invent an outgoing EOF on receipt of an
incoming CHANNEL_CLOSE, if it's the main session channel. The idea is
that invocations such as 'plink -T hostname sh' (running a shell
without a remote pty) can be exited by typing 'exit' to the remote
shell, without plink blocking forever waiting for outgoing EOF.

I think it would be better to do the same for all other channel types
too, but that would need an extra API call which I haven't
implemented yet.

[originally from svn r9283]
2011-09-14 09:09:35 +00:00
Simon Tatham
6e2bcd24a4 Changed my mind about the EOF policy in SSH mode: I think the SSH
backend should unilaterally assume outgoing EOF when it sees incoming
EOF, if and only if the main session channel is talking to a pty.
(Because ptys don't have a strong concept of EOF in the first place,
that seems like a sensible place to draw the line.) This fixes a bug
introduced by today's revamp in which if you used Unix Plink to run a
console session it would hang after you hit ^D - because the server
had sent EOF, but it was waiting for a client-side EOF too.

[originally from svn r9282]
2011-09-13 15:38:12 +00:00
Simon Tatham
5848c8cc3d Nearly forgot noting this down in the 'half-closed' bug entry: don't
send CHANNEL_CLOSE until we have acks for all our winadj requests.
Should work around https://bugzilla.mindrot.org/show_bug.cgi?id=1818 .

[originally from svn r9280]
2011-09-13 11:56:25 +00:00
Simon Tatham
947962e0b9 Revamp of EOF handling in all network connections, pipes and other
data channels. Should comprehensively fix 'half-closed', in principle,
though it's a big and complicated change and so there's a good chance
I've made at least one mistake somewhere.

All connections should now be rigorous about propagating end-of-file
(or end-of-data-stream, or socket shutdown, or whatever) independently
in both directions, except in frontends with no mechanism for sending
explicit EOF (e.g. interactive terminal windows) or backends which are
basically always used for interactive sessions so it's unlikely that
an application would be depending on independent EOF (telnet, rlogin).

EOF should now never accidentally be sent while there's still buffered
data to go out before it. (May help fix 'portfwd-corrupt', and also I
noticed recently that the ssh main session channel can accidentally
have MSG_EOF sent before the output bufchain is clear, leading to
embarrassment when it subsequently does send the output).

[originally from svn r9279]
2011-09-13 11:44:03 +00:00
Simon Tatham
363f57396f Minor amendment to r9226: don't log GSSAPI failure in the Event Log
twice. (Once in the GSSAPI code, once at the top of the main auth
loop. Removed the latter.)

[originally from svn r9232]
[r9226 == 0b79fe0bcb]
2011-07-18 18:09:36 +00:00
Simon Tatham
0b79fe0bcb Reorganise the logging and display of messages about SSH
authentication. We should now produce an Event Log entry for every
authentication attempted and every authentication failure; meanwhile,
messages in the PuTTY window will not be generated for the failure of
auth types unless we also announced in the PuTTY window that we were
trying them. (GSSAPI was getting the latter wrong, leading to spurious
'Access denied' for many users of 0.61.)

[originally from svn r9226]
2011-07-16 12:06:32 +00:00
Simon Tatham
a1f3b7a358 Post-release destabilisation! Completely remove the struct type
'Config' in putty.h, which stores all PuTTY's settings and includes an
arbitrary length limit on every single one of those settings which is
stored in string form. In place of it is 'Conf', an opaque data type
everywhere outside the new file conf.c, which stores a list of (key,
value) pairs in which every key contains an integer identifying a
configuration setting, and for some of those integers the key also
contains extra parts (so that, for instance, CONF_environmt is a
string-to-string mapping). Everywhere that a Config was previously
used, a Conf is now; everywhere there was a Config structure copy,
conf_copy() is called; every lookup, adjustment, load and save
operation on a Config has been rewritten; and there's a mechanism for
serialising a Conf into a binary blob and back for use with Duplicate
Session.

User-visible effects of this change _should_ be minimal, though I
don't doubt I've introduced one or two bugs here and there which will
eventually be found. The _intended_ visible effects of this change are
that all arbitrary limits on configuration strings and lists (e.g.
limit on number of port forwardings) should now disappear; that list
boxes in the configuration will now be displayed in a sorted order
rather than the arbitrary order in which they were added to the list
(since the underlying data structure is now a sorted tree234 rather
than an ad-hoc comma-separated string); and one more specific change,
which is that local and dynamic port forwardings on the same port
number are now mutually exclusive in the configuration (putting 'D' in
the key rather than the value was a mistake in the first place).

One other reorganisation as a result of this is that I've moved all
the dialog.c standard handlers (dlg_stdeditbox_handler and friends)
out into config.c, because I can't really justify calling them generic
any more. When they took a pointer to an arbitrary structure type and
the offset of a field within that structure, they were independent of
whether that structure was a Config or something completely different,
but now they really do expect to talk to a Conf, which can _only_ be
used for PuTTY configuration, so I've renamed them all things like
conf_editbox_handler and moved them out of the nominally independent
dialog-box management module into the PuTTY-specific config.c.

[originally from svn r9214]
2011-07-14 18:52:21 +00:00
Jacob Nevins
3a649ed4ed Fix 'winadj-success': since at least one server (boks_sshd) blithely responds
to "winadj@putty.projects.tartarus.org" with SSH_MSG_CHANNEL_SUCCESS despite
probably having no idea what it means, treat this just the same as
SSH_MSG_CHANNEL_FAILURE instead of killing the connection.
Tested only as far as making sure that winadj/FAILURE with a normal server
isn't _completely_ broken.

[originally from svn r9185]
[this svn revision also touched putty-wishlist]
2011-07-01 21:53:41 +00:00