a single function which also handles checking that channels exist and
are properly open. This should make PuTTY a little less tolerant of
servers that send bogus messages.
[originally from svn r7751]
performance. The theory behind this is fairly simple, though the
implementation turns out to be a little trickier than it looks.
The basic idea is that when the connection isn't being limited by our ability
to process data, we want to ensure that the window size _as seen by the server_
never drops to zero. Measuring the server's view of the window size is done
by arranging for it to acknowledge every SSH_MSG_CHANNEL_WINDOW_ADJUST, or
rather an SSH_MSG_CHANNEL_REQUEST sent just before it. That way we can tell
when it its outgoing data stream it received the window adjustment, and
thus how small the server's view of the window got.
At present, we only ever increase the window size. In theory, we could
arrange to reduce it again if the server's view of it seemed to be persistently
too large, but my experiments suggest that getting this right will be tricky.
[originally from svn r7735]
for it. It's possible that this obsoletes BUG_CHOKES_ON_RSA. Certainly
the one SSH-1.5-Cisco-1.25 server I found was correctly not advertising RSA
auth. For now, leave it in, because I'm not feeling entirely confident.
[originally from svn r7726]
because it can ever be negative, but because we'll be comparing it with
another int. This way, C's promotion rules don't bite us and we should
stand slightly more chance of coping with broken servers that overrun our
window.
[originally from svn r7683]
and tweak ssh2_set_window() so it can cope with that. Also arrange to send
a private channel message in simple mode to tell the server that it can safely
use a large window too.
[originally from svn r7679]
channel, arrange to set the SSH-2 window size to something very
large. This prevents the connection stalling when the window fills
up, and means that PSCP receives data _much_ faster.
[originally from svn r7672]
used up, rather than over half. That this increases the throughput of PSCP
by 50% indicates just how broken our window handling is.
[originally from svn r7667]
arrange to handle usefully the case where the server sends us more data
than it's allowed to. There's no danger of overflow, since the maximum is
OUR_V2_WINSIZE and the minimum is -OUR_V2_MAXPKT (at least if the server is
nice).
[originally from svn r7661]
instead of a bitfield for both. This doesn't gain much here, but it should
make it easier to make things other than logging use the context.
[originally from svn r7647]
This allows us to send data in ssh_init(), albeit at the expense of its not
being properly logged, so arrange to send the version string then if that's
sensible, which should reduce the number of round-trips required to bring
up an SSH-2 connection.
[originally from svn r7646]
the SSH-2-only case, we can send it as soon as we connect rather than waiting
for the server's one. Unfortunately, actually doing so will take a little
more effort -- there are subtleties to do with having a working log context
at the right moment that need to be sorted out.
[originally from svn r7645]
Should be no significant change in behaviour.
(Well, entering usernames containing commas on Plink's command line will be
a little harder now.)
[originally from svn r7628]
remember to put an empty string in it rather than sending a completely
empty packet. This should help with those servers (notably RomSShell)
that actually check the contents of SSH_MSG_IGNORE.
[originally from svn r7236]
will close the window even in `close window only on clean exit'
mode. Also, while I'm here, arrange a suitable exit code for
"exit-signal".
[originally from svn r7121]
ability to easily re-enable the r5122 behaviour, in case we need to
conditionally switch between the two at a later date.
[originally from svn r7073]
[r5122 == 8a20515844]
[this svn revision also touched putty-wishlist]
(Since we choose to compile with -Werror, this is particularly important.)
I haven't yet checked that the resulting source actually compiles cleanly with
GCC 4, hence not marking `gcc4-warnings' as fixed just yet.
[originally from svn r7041]
BUG_NEEDS_SSH1_PLAIN_PASSWORD do exactly what it says on the tin, independent
of whether BUG_CHOKES_ON_SSH1_IGNORE is set.
This is invisible in the default configuration, as all servers marked as having
the second bug have the first one too, but it would allow one to manually
configure PuTTY to cope with a SSH-1 server that got upset by ignore messages
during authentication, but was fine with their use as keepalives.
[originally from svn r6876]
in an SSH connection _in addition_ to the decrypted packets. This
will hopefully come in useful for debugging wire data corruption
issues: you can strace the server, enable this mode in the client,
and compare the sent and received data.
I'd _like_ to have this mode also log Diffie-Hellman private
exponents, session IDs, encryption and MAC keys, so that the
resulting log file could be used to independently verify the
correctness of all cryptographic operations performed by PuTTY.
However, I haven't been able to convince myself that the security
implications are acceptable. (It doesn't matter that this
information would permit an attacker to decrypt the session, because
the _already_ decrypted session is stored alongside it in the log
file. And I'm not planning, under any circumstances, to log users'
private keys. But gaining access to the log file while the session
was still running would permit an attacker to _hijack_ the session,
and that's the iffy bit.)
[originally from svn r6835]
there): `plink host -nc host2:port' causes the SSH connection's main
channel to be replaced with a direct-tcpip connection to the
specified destination. This feature is mainly designed for use as a
local proxy: setting your local proxy command to `plink %proxyhost
-nc %host:%port' lets you tunnel SSH over SSH with a minimum of
fuss. Works on all platforms.
[originally from svn r6823]
it's NULL. Since we already have one back end (uxpty) which doesn't
in fact talk to a network socket, and may well have more soon, I'm
replacing this TCP/IP-centric function with a nice neutral
`connected' function returning a boolean. Nothing else about its
semantics has currently changed.
[originally from svn r6810]
session termination. `Close window only on clean exit' was not
working properly on Unix in the absence of this:
notify_remote_exit() was being called and ssh_return_exitcode was
returning zero, causing gtk_main_quit() to be called, _before_
connection_fatal() happened.
[originally from svn r6801]
Pageant for local authentication. (This is a `don't use Pageant for
authentication at session startup' button rather than a `pretend
Pageant doesn't exist' button: that is, agent forwarding is
independent of this option.)
[originally from svn r6572]
to be from IP "client-side-connection". Claiming "0.0.0.0" instead seems to
work. Spotted by Brant Thomsen.
[originally from svn r6477]
[this svn revision also touched putty-wishlist]
that the SSH-2 server is happy with. Fixed, and since I'm here, fix
`pubkeyfile-and-pageant' as well (for SSH-1 and SSH-2).
Also, in SSH-2, we now reexamine "methods that can continue" for every
Pageant key offer, which is technically more correct although it seems
unlikely that it was causing any real problems.
(It's not entirely pretty, but neither was the old code. We could probably
do with some sort of abstraction for public/private keys to avoid carting
lots of fiddly bits of data around.)
[originally from svn r6459]
[r6437 == 8719f92c14]
[this svn revision also touched putty-wishlist]
(Much easier since r6437, and actually works to boot.)
[originally from svn r6445]
[r6437 == 8719f92c14]
[this svn revision also touched putty-wishlist]
abstracted out; replace loops structured around a single interaction
per loop with less tortuous code (fixes: `ki-multiprompt-crash',
`ssh1-bad-passphrase-crash'; makes `ssh2-password-expiry' and
`proxy-password-prompt' easier).
The new interaction abstraction has a lot of fields that are unused in
the current code (things like window captions); this is groundwork for
`gui-auth'. However, ssh.c still writes directly to stderr; that may
want to be fixed.
In the GUI apps, user interaction is moved to terminal.c. This should
make it easier to fix things like UTF-8 username entry, although I
haven't attempted to do so. Also, control character filtering can be
tailored to be appropriate for individual front-ends; so far I don't
promise anything other than not having made it any worse.
I've tried to test this fairly exhaustively (although Mac stuff is
untested, as usual). It all seems to basically work, but I bet there
are new bugs. (One I know about is that you can no longer make the
PuTTY window go away with a ^D at the password prompt; this should be
fixed.)
[originally from svn r6437]
[this svn revision also touched putty-wishlist]
packets over about 256 bytes would be logged with 12 bytes of preceding
garbage. (But the rest of the packet was logged in its entirety. This
holds for packets where (int(len/256)%2)==1, with an appropriate fudge
factor applied to `len'.) Ahem.
[originally from svn r6429]
[r5642 == c09d885b27]
patched OpenSSH server. This is controlled by the same user settings
as diffie-hellman-group-exchange-sha1, which may not be optimal, especially
given that they're both referred to as dh-gex-sha1 in saved sessions.
[originally from svn r6272]
storing a SHA-1 hash of the client and server version strings, store the
strings themselves so we can feed them through the appropriate hash when
we know what it is.
[originally from svn r6241]
processed and incoming data being processed out of order, which I suspect is
the cause of `ssh1-fwd-trouble' as noted by Gevan Dutton. I'm not able to
test the failure case, but it doesn't seem to have obviously broken anything
in the cases I have tested, anyway.
[originally from svn r6221]
marks a version string. It's a bit vague about the definition of a line,
but I think it's reasonable to assume that they'll end with LF. Change
do_ssh_init() to ignore "SSH-" anywhere else. This makes the existing state
machine overkill, so replace it with something a little more readable.
[originally from svn r6138]
do_ssh2_transport() was returning the wrong value for rekeys after the first.
This apparent error was introduced in r4901, but we can't see any reason for
the change to have been made. If it turns out to be a mistake to revert it,
I'm sure we'll find out.
Here for posterity is Simon's analysis:
| A lot of the return values from do_ssh2_transport appear to be vestigial: it
| used to be that a zero return from do_ssh2_transport meant it had handled the
| packet internally, and a 1 return meant the packet wasn't a transport-layer
| one and needed to pass on to do_ssh2_authconn. Since r4901, however, the
| layer discrimination is done based on the message type ranges, and the only
| remaining dependency on the return value from do_ssh2_transport is a special
| case in ssh2_protocol which detects the first 1 return and makes the
| initialisation call to do_ssh2_authconn.
|
| Therefore, the gratuitous 1 return on every key exchange as a result of the
| confusing if statement is simply ignored in ssh2_protocol (because
| ssh->protocol_initial_phase_done is already TRUE). So the remaining question
| was, why does the _lack_ of that 1 return not cause a problem, if the if's
| sense is indeed reversed?
|
| The answer is that 1 is still returned, just not by the crReturn inside the
| if statement. It's returned by the next crReturn, just after
| wait_for_rekey(). Which suggests that in fact, the if statement has the
| correct sense, but the crReturn inside it has the wrong value - it should be
| returning _zero_, to indicate that every NEWKEYS after the first one is
| uninteresting to the authconn code, and on the very first run through that
| doesn't happen and the NEWKEYS gets all the way to the crReturn(1) later on.
[originally from svn r5986]
[r4901 == a4ba026838]
enforce the following:
* Packet must have at least one byte of payload and four bytes of padding.
* Total packet length must not exceed 35000 bytes compressed.
* Total packet length including length field must be a multiple of cipher
block size (or eight bytes).
The feebleness of our old checks was noticed by Ben Rudiak-Gould.
[originally from svn r5981]
and add the ability to treat a local disconnection as "unclean" -- notably, if
we can't agree any authentication methods to even try; someone was complaining
that the PuTTY window by default just disappears for no apparent reason in this
circumstance.
Also, use appropriate disconnect codes for those SSH2_MSG_DISCONNECT messages
that we do send.
I don't think I've seriously broken any user-visible behaviour, but the way
that connection-close distinctions are transmitted to the front-end is shaky
(or so it seems to me), so there may be non-ideal changes on some platforms.
[originally from svn r5824]
hopefully solve `drop-banner'. I haven't been able to test the failure case,
but the behaviour with OpenSSH appears no worse.
[originally from svn r5772]
[this svn revision also touched putty-wishlist]
there are servers which could in principle operate in this mode, although I
don't know if any do in practice. (Hence, I haven't been able to test it.)
[originally from svn r5748]
[this svn revision also touched putty-wishlist]
server, which led to stalemate if the server did the same. PuTTY now sends
KEXINIT proactively as soon as it's worked out that it's talking SSH-2.
[originally from svn r5685]
default preferred cipher), add code to inject SSH_MSG_IGNOREs to randomise
the IV when using CBC-mode ciphers. Each cipher has a flag to indicate
whether it needs this workaround, and the SSH packet output maze has gained
some extra complexity to implement it.
[originally from svn r5659]
Unix Plink sends everything sensible it can find, and it's fully configurable
from the GUI.
I'm not entirely sure about the precise set of modes that Unix Plink should
look at; informed tweaks are welcome.
Also the Mac bits are guesses (but trivial).
[originally from svn r5653]
[this svn revision also touched putty-wishlist]
end, after the REQUIRED "hmac-sha1".) This has been present since SSH-2
support was introduced (r569).
[originally from svn r5643]
[r569 == 35205e5cb7]
I've added this to support `terminal-modes', but since this unifies some
SSH-1 and SSH-2 packet construction code, it saves a few hundred bytes.
Bonus.
[originally from svn r5642]
comp.security.ssh contains a Dr Watson log which looks to me as if
`unclean-close-crash' occurred due to a rekey timer going off after
the session had closed. Hence, ssh2_timer() now avoids doing
anything if the session is already closed, and also ssh_do_close()
proactively calls expire_timer_context(). Between those I think they
ought to solve the problem.
[originally from svn r5564]
ssh2_try_send() to no longer be run after receiving WINDOW_ADJUSTs.
I believe this is likely to have been the cause of recent PSCP
hanging issues.
[originally from svn r5517]
[r4909 == 02b0474f57]
discussed. Use Barrett and Silverman's convention of "SSH-1" for SSH protocol
version 1 and "SSH-2" for protocol 2 ("SSH1"/"SSH2" refer to ssh.com
implementations in this scheme). <http://www.snailbook.com/terms.html>
[originally from svn r5480]
prompts, to make it more obvious if a server is attempting to spoof a local
passphrase prompt.
I believe an alert user could have spotted this in all cases in SSH-2,
although perhaps not in SSH-1. (But they'd have to have enabled
TIS/CryptoCard.)
[originally from svn r5450]
Port forwardings are set up before initialising the last few details
of the main shell session, so ssh->state can reasonably hold values
other than SSH_STATE_SESSION and SSH_STATE_CLOSED during calls to
sshfwd_*.
[originally from svn r5446]
connection_fatal(), since the latter is entitled to destroy the
backend so `ssh' may no longer be valid once it returns.
For the Unix port, switch exit(0) to gtk_main_quit() in
notify_remote_exit(), so that we don't exit before the subsequent
connection_fatal()!
[originally from svn r5445]
