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mirror of https://git.tartarus.org/simon/putty.git synced 2025-01-10 01:48:00 +00:00
putty-source/windows
Simon Tatham 5e2acd9af7 New bug workaround: KEXINIT filtering.
We've occasionally had reports of SSH servers disconnecting as soon as
they receive PuTTY's KEXINIT. I think all such reports have involved
the kind of simple ROM-based SSH server software you find in small
embedded devices.

I've never been able to prove it, but I've always suspected that one
possible cause of this is simply that PuTTY's KEXINIT is _too long_,
either in number of algorithms listed or in total length (especially
given all the ones that end in @very.long.domain.name suffixes).

If I'm right about either of those being the cause, then it's just
become even more likely to happen, because of all the extra
Diffie-Hellman groups and GSSAPI algorithms we just threw into our
already-long list in the previous few commits.

A workaround I've had in mind for ages is to wait for the server's
KEXINIT, and then filter our own down to just the algorithms the
server also mentioned. Then our KEXINIT is no longer than that of the
server, and hence, presumably fits in whatever buffer it has. So I've
implemented that workaround, in anticipation of it being needed in the
near future.

(Well ... it's not _quite_ true that our KEXINIT is at most the same
length as the server. In fact I had to leave in one KEXINIT item that
won't match anything in the server's list, namely "ext-info-c" which
gates access to SHA-2 based RSA. So if we turn out to support
absolutely everything on all the server's lists, then our KEXINIT
would be a few bytes longer than the server's, even with this
workaround. But that would only cause trouble if the server's outgoing
KEXINIT was skating very close to whatever buffer size it has for the
incoming one, and I'm guessing that's not very likely.)

((Another possible cause of this kind of disconnection would be a
server that simply objects to seeing any KEXINIT string it doesn't
know how to speak. But _surely_ no such server would have survived
initial testing against any full-featured client at all!))
2022-08-30 18:51:33 +01:00
..
utils Implement AES-GCM using the @openssh.com protocol IDs. 2022-08-16 20:33:58 +01:00
agent-client.c Formatting: standardise on "func(\n", not "func\n(". 2022-08-03 20:48:46 +01:00
cliloop.c Reorganise Windows HANDLE management. 2021-05-24 15:27:38 +01:00
CMakeLists.txt Move host CA config box out into its own source file. 2022-05-01 10:16:19 +01:00
config.c Macro wrapper on ctrl_radiobuttons to fill in the NULL. 2022-06-01 11:14:21 +01:00
conpty.c pterm.exe: load the ConPTY API at run time. 2022-05-21 09:53:03 +01:00
console.c Centralise most details of host-key prompting. 2022-07-07 18:05:32 +01:00
controls.c Formatting: realign run-on parenthesised stuff. 2022-08-03 20:48:46 +01:00
cryptoapi.h Rename most of the platform source files. 2021-04-26 18:00:01 +01:00
dialog.c Remove redundant setup of host key prompt help contexts. 2022-08-07 18:36:44 +01:00
gss.c Formatting: realign run-on parenthesised stuff. 2022-08-03 20:48:46 +01:00
handle-io.c Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00
handle-socket.c Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00
handle-wait.c Fix an unused variable. 2021-05-27 09:48:32 +01:00
help.c windows/storage.c: factor out low-level Registry access. 2022-04-24 08:38:27 +01:00
help.h New bug workaround: KEXINIT filtering. 2022-08-30 18:51:33 +01:00
help.rc2 Rename most of the platform source files. 2021-04-26 18:00:01 +01:00
installer.wxs Configurable CHM path in installer source. 2021-05-03 17:01:55 +01:00
jump-list.c Formatting: miscellaneous. 2022-08-03 20:48:46 +01:00
local-proxy.c Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00
make_install_images.sh Remove white dialog background in MSI user interface. 2020-06-21 16:39:47 +01:00
msifixup.py Remove white dialog background in MSI user interface. 2020-06-21 16:39:47 +01:00
named-pipe-client.c Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00
named-pipe-server.c Formatting: standardise on "func(\n", not "func\n(". 2022-08-03 20:48:46 +01:00
network.c Formatting: remove spurious spaces in 'type * var'. 2022-08-03 20:48:46 +01:00
no-jump-list.c Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00
nohelp.c Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00
noise.c Rename most of the platform source files. 2021-04-26 18:00:01 +01:00
pageant-rc.h winpgnt: say 'click to focus' in async passphrase prompt. 2021-04-22 20:00:46 +01:00
pageant.c Certificate-aware handling of key fingerprints. 2022-08-05 18:08:59 +01:00
pageant.ico
pageant.mft Whitespace rationalisation of entire code base. 2019-09-08 20:29:21 +01:00
pageant.rc Certificate-aware handling of key fingerprints. 2022-08-05 18:08:59 +01:00
pageants.ico
platform.h Windows PuTTYgen: also display certificate info. 2022-07-30 17:16:55 +01:00
plink.c Centralise most details of host-key prompting. 2022-07-07 18:05:32 +01:00
plink.rc
printing.c Formatting: realign labels and case/default statements. 2022-08-03 20:48:46 +01:00
pscp.ico
pscp.rc
psftp.rc
psocks.c Rename most of the platform source files. 2021-04-26 18:00:01 +01:00
pterm.c pterm.exe: run command-line options through cmdline.c. 2022-05-21 10:34:17 +01:00
pterm.ico Make Windows versions of the pterm icons. 2021-05-08 17:33:25 +01:00
pterm.rc New application: a Windows version of 'pterm'! 2021-05-08 17:51:27 +01:00
ptermcfg.ico Make Windows versions of the pterm icons. 2021-05-08 17:33:25 +01:00
putty-common.rc2 Centralise most details of host-key prompting. 2022-07-07 18:05:32 +01:00
putty-rc.h Centralise most details of host-key prompting. 2022-07-07 18:05:32 +01:00
putty.c Merge assorted pterm fixes from 'pre-0.77'. 2022-05-21 10:59:31 +01:00
putty.ico
putty.mft Windows 10: add per monitor DPI awareness support. 2021-04-02 19:04:19 +01:00
putty.rc Move icon declarations out of putty-common.rc2. 2021-05-08 17:33:25 +01:00
puttycfg.ico
puttygen-rc.h PuTTYgen: option to control Argon2 flavour. 2021-02-23 18:26:50 +00:00
puttygen.c Formatting: standardise on "func(\n", not "func\n(". 2022-08-03 20:48:46 +01:00
puttygen.ico
puttygen.mft Whitespace rationalisation of entire code base. 2019-09-08 20:29:21 +01:00
puttygen.rc Windows PuTTYgen: also display certificate info. 2022-07-30 17:16:55 +01:00
puttyins.ico
puttytel.mft Windows 10: add per monitor DPI awareness support. 2021-04-02 19:04:19 +01:00
puttytel.rc Move icon declarations out of putty-common.rc2. 2021-05-08 17:33:25 +01:00
rcstuff.h Replace mkfiles.pl with a CMake build system. 2021-04-17 13:53:02 +01:00
README-msi.txt Remove note about .CHM on network drives. 2019-03-18 21:53:45 +00:00
security-api.h Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00
select-cli.c Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00
select-gui.c Handle WM_NETEVENT in Windows Pageant. 2022-02-04 19:32:47 +00:00
serial.c Add memsets after allocation of all Backend implementors. 2021-10-30 17:28:28 +01:00
sftp.c Formatting: realign labels and case/default statements. 2022-08-03 20:48:46 +01:00
sharing.c Windows: factor out mutex lock/unlock from sharing.c. 2022-01-03 12:12:05 +00:00
sizetip.c Formatting change to braces around one case of a switch. 2020-02-16 11:26:21 +00:00
storage.c Formatting: standardise on "func(\n", not "func\n(". 2022-08-03 20:48:46 +01:00
test_screenshot.c Standalone screenshot utility. 2022-04-02 17:26:24 +01:00
unicode.c Formatting: miscellaneous. 2022-08-03 20:48:46 +01:00
version.rc2 FIXME about Windows resource CHMfulness hint. 2019-03-18 22:02:13 +00:00
website.url Switch chiark URLs to https. 2017-05-07 16:29:01 +01:00
win-gui-seat.h Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00
window.c Formatting: miscellaneous. 2022-08-03 20:48:46 +01:00
x11.c Update source file names in comments and docs. 2022-01-22 15:51:31 +00:00