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Simon Tatham 25b034ee39 Complete rewrite of PuTTY's bignum library.
The old 'Bignum' data type is gone completely, and so is sshbn.c. In
its place is a new thing called 'mp_int', handled by an entirely new
library module mpint.c, with API differences both large and small.

The main aim of this change is that the new library should be free of
timing- and cache-related side channels. I've written the code so that
it _should_ - assuming I haven't made any mistakes - do all of its
work without either control flow or memory addressing depending on the
data words of the input numbers. (Though, being an _arbitrary_
precision library, it does have to at least depend on the sizes of the
numbers - but there's a 'formal' size that can vary separately from
the actual magnitude of the represented integer, so if you want to
keep it secret that your number is actually small, it should work fine
to have a very long mp_int and just happen to store 23 in it.) So I've
done all my conditionalisation by means of computing both answers and
doing bit-masking to swap the right one into place, and all loops over
the words of an mp_int go up to the formal size rather than the actual
size.

I haven't actually tested the constant-time property in any rigorous
way yet (I'm still considering the best way to do it). But this code
is surely at the very least a big improvement on the old version, even
if I later find a few more things to fix.

I've also completely rewritten the low-level elliptic curve arithmetic
from sshecc.c; the new ecc.c is closer to being an adjunct of mpint.c
than it is to the SSH end of the code. The new elliptic curve code
keeps all coordinates in Montgomery-multiplication transformed form to
speed up all the multiplications mod the same prime, and only converts
them back when you ask for the affine coordinates. Also, I adopted
extended coordinates for the Edwards curve implementation.

sshecc.c has also had a near-total rewrite in the course of switching
it over to the new system. While I was there, I've separated ECDSA and
EdDSA more completely - they now have separate vtables, instead of a
single vtable in which nearly every function had a big if statement in
it - and also made the externally exposed types for an ECDSA key and
an ECDH context different.

A minor new feature: since the new arithmetic code includes a modular
square root function, we can now support the compressed point
representation for the NIST curves. We seem to have been getting along
fine without that so far, but it seemed a shame not to put it in,
since it was suddenly easy.

In sshrsa.c, one major change is that I've removed the RSA blinding
step in rsa_privkey_op, in which we randomise the ciphertext before
doing the decryption. The purpose of that was to avoid timing leaks
giving away the plaintext - but the new arithmetic code should take
that in its stride in the course of also being careful enough to avoid
leaking the _private key_, which RSA blinding had no way to do
anything about in any case.

Apart from those specific points, most of the rest of the changes are
more or less mechanical, just changing type names and translating code
into the new API.
2018-12-31 14:54:59 +00:00
charset Add missing 'static' on file-internal declarations. 2018-11-03 13:45:00 +00:00
contrib Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
doc Update UDP to mention the inttypes.h exception. 2018-11-22 07:09:06 +00:00
icons Make an OS X icon for pterm as well as PuTTY. 2016-03-23 22:02:46 +00:00
testdata Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
unix Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
windows Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
.gitignore Move the ZLIB_STANDALONE main() into its own file. 2018-11-27 19:59:45 +00:00
agentf.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
aqsync.c Build outgoing SSH agent requests in a strbuf. 2018-05-25 14:36:16 +01:00
be_all_s.c Name vtable structure types more consistently. 2018-10-06 07:28:51 +01:00
be_all.c Name vtable structure types more consistently. 2018-10-06 07:28:51 +01:00
be_misc.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
be_none.c Name vtable structure types more consistently. 2018-10-06 07:28:51 +01:00
be_nos_s.c Name vtable structure types more consistently. 2018-10-06 07:28:51 +01:00
be_nossh.c Name vtable structure types more consistently. 2018-10-06 07:28:51 +01:00
be_ssh.c Name vtable structure types more consistently. 2018-10-06 07:28:51 +01:00
Buildscr Server prep: pass "implementation name" to ssh_verstring_new. 2018-10-21 10:02:10 +01:00
Buildscr.cv Rename Makefile.cyg to Makefile.mgw. 2016-04-10 15:10:45 +01:00
callback.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
cgtest.c cmdgen: rescue test suite from bit rot. 2016-03-30 08:34:14 +01:00
CHECKLST.txt Rework the release checklist for current practice. 2017-07-03 07:45:40 +01:00
cmdgen.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
cmdline.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
conf.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
config.c Remove some redundant variables and assignments. 2018-12-01 17:00:01 +00:00
configure.ac Add an SFTP server to the SSH server code. 2018-10-21 10:02:10 +01:00
cproxy.c Get rid of #ifdef DEFINE_PLUG_METHOD_MACROS. 2018-10-06 07:28:51 +01:00
defs.h Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
dialog.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
dialog.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ecc.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
ecc.h Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
errsock.c Improve sk_peer_info. 2018-10-21 10:02:10 +01:00
fuzzterm.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
import.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
LATEST.VER Update version number for 0.70 release. 2017-07-04 20:29:54 +01:00
ldisc.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ldisc.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ldiscucs.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
LICENCE Copyright holders update after GSS kex. 2018-04-26 07:21:29 +01:00
licence.pl Autogenerate licence text in doc subdir from LICENCE. 2015-12-22 13:33:42 +00:00
logging.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
mainchan.c Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
marshal.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
marshal.h Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
memory.c Move the malloc helpers out of misc.c. 2018-11-27 19:59:45 +00:00
minibidi.c Add missing 'static' on file-internal declarations. 2018-11-03 13:45:00 +00:00
misc.c pscp, psftp: use a bufchain in ssh_scp_recv. 2018-12-01 16:56:25 +00:00
misc.h Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
miscucs.c New centralised helper function dup_mb_to_wc(). 2015-07-27 20:06:02 +01:00
mkauto.sh Move the Unix configure script up to the top level. 2014-02-22 18:01:32 +00:00
mkfiles.pl Makefile.clangcl: move $(CCTARGET) out of $(CC). 2018-12-06 18:41:30 +00:00
mksrcarc.sh New script to generate OS X icon files. 2015-09-06 10:12:15 +01:00
mkunxarc.sh Turn mkunxarc.sh back into an ordinary sh script. 2014-10-01 20:52:16 +00:00
mpint_i.h Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
mpint.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
mpint.h Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
network.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
nocmdline.c Adopt C99 <stdbool.h>'s true/false. 2018-11-03 13:45:00 +00:00
nocproxy.c Get rid of #ifdef DEFINE_PLUG_METHOD_MACROS. 2018-10-06 07:28:51 +01:00
nogss.c Rewrite gprefs() in settings.c so that its input mapping includes 2011-06-25 17:37:31 +00:00
noprint.c A few small changes to make the PuTTY source base more usable as a 2005-12-09 20:04:19 +00:00
noshare.c Get rid of lots of implicit pointer types. 2018-10-04 19:10:23 +01:00
noterm.c Make calling term_nopaste() a cross-platform feature. 2013-08-17 16:06:40 +00:00
notiming.c Two related changes to timing code: 2012-09-18 21:42:48 +00:00
nullplug.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
pageant.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
pageant.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
pgssapi.c Fix a missing } in a GSSAPI-related comment. 2018-04-26 07:11:09 +01:00
pgssapi.h Adopt C99 <stdint.h> integer types. 2018-11-03 13:25:50 +00:00
pinger.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
portfwd.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
pproxy.c Get rid of lots of implicit pointer types. 2018-10-04 19:10:23 +01:00
proxy.c Replace several ad-hoc string formatters with strbuf. 2018-12-01 16:52:35 +00:00
proxy.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
pscp.c pscp: replace crash with diagnostic on opendir failure. 2018-12-27 16:52:23 +00:00
psftp.c pscp: replace crash with diagnostic on opendir failure. 2018-12-27 16:52:23 +00:00
psftp.h pscp: replace crash with diagnostic on opendir failure. 2018-12-27 16:52:23 +00:00
putty.h Centralise key escape sequences into terminal.c. 2018-12-08 16:08:47 +00:00
puttymem.h New memory management macro 'snew_plus'. 2018-06-06 07:22:06 +01:00
puttyps.h Delete the old 'macosx' directory completely. 2016-03-25 09:06:03 +00:00
raw.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
README Remove Makefile.bor. 2017-09-13 19:26:28 +01:00
Recipe Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
release.pl Add a --no-ftp mode to the release.pl download checks. 2017-07-08 09:27:57 +01:00
resource.h Initial checkin: beta 0.43 1999-01-08 13:02:13 +00:00
rlogin.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
scpserver.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
sercfg.c Move all extern declarations into header files. 2018-11-03 13:47:29 +00:00
sesschan.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
sessprep.c Factor out common pre-session-launch preparation. 2017-12-03 14:54:49 +00:00
settings.c Add some more miscellaneous asserts. 2018-12-01 17:04:44 +00:00
sftp.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
sftp.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
sftpcommon.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
sftpserver.c Adopt C99 <stdbool.h>'s true/false. 2018-11-03 13:45:00 +00:00
sign.sh GPG key rollover. 2018-08-25 14:38:47 +01:00
ssh1bpp.c Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
ssh1censor.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ssh1connection-client.c Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
ssh1connection-server.c Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
ssh1connection.c Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
ssh1connection.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ssh1login-server.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
ssh1login.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
ssh2bpp-bare.c Stop BPPs from handling EOF before reading all data. 2018-11-28 20:19:59 +00:00
ssh2bpp.c Remove a load of obsolete printf string limits. 2018-12-08 21:06:59 +00:00
ssh2censor.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ssh2connection-client.c Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
ssh2connection-server.c Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
ssh2connection.c Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
ssh2connection.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ssh2kex-client.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
ssh2kex-server.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
ssh2transhk.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ssh2transport.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
ssh2transport.h Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
ssh2userauth-server.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ssh2userauth.c Remove a load of obsolete printf string limits. 2018-12-08 21:06:59 +00:00
ssh.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
ssh.h Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshaes.c Remove some redundant variables and assignments. 2018-12-01 17:00:01 +00:00
ssharcf.c Make ssh_key and ssh{2,1}_cipher into structs. 2018-11-26 21:02:28 +00:00
sshbcrypt.c Replace all uses of SHA*_Bytes / MD5Update. 2018-05-25 14:36:16 +01:00
sshblowf.c Make ssh_key and ssh{2,1}_cipher into structs. 2018-11-26 21:02:28 +00:00
sshblowf.h Turn SSH-2 ciphers into a classoid. 2018-09-19 23:08:07 +01:00
sshbpp.h Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
sshccp.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshchan.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
sshcommon.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshcr.h Tweak crWaitUntil macros for greater robustness. 2018-09-24 18:50:25 +01:00
sshcrc.c Fix a 64-bit-cleanness error in sshcrc's generator. 2016-01-26 22:09:01 +00:00
sshcrcda.c Add some more miscellaneous asserts. 2018-12-01 17:04:44 +00:00
sshdes.c Make ssh_key and ssh{2,1}_cipher into structs. 2018-11-26 21:02:28 +00:00
sshdh.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshdss.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshdssg.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshecc.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshecdsag.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshgss.h Move most of ssh.c out into separate source files. 2018-09-24 19:45:22 +01:00
sshgssc.c Support GSS key exchange, for Kerberos 5 only. 2018-04-26 07:21:16 +01:00
sshgssc.h Support GSS key exchange, for Kerberos 5 only. 2018-04-26 07:21:16 +01:00
sshmac.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
sshmd5.c Adopt C99 <stdint.h> integer types. 2018-11-03 13:25:50 +00:00
sshnogss.c Post-release destabilisation! Completely remove the struct type 2011-07-14 18:52:21 +00:00
sshppl.h Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
sshprime.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshpubk.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshrand.c Move all extern declarations into header files. 2018-11-03 13:47:29 +00:00
sshrsa.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshrsag.c Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshserver.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
sshserver.h Complete rewrite of PuTTY's bignum library. 2018-12-31 14:54:59 +00:00
sshsh256.c Adopt C99 <stdint.h> integer types. 2018-11-03 13:25:50 +00:00
sshsh512.c Adopt C99 <stdint.h> integer types. 2018-11-03 13:25:50 +00:00
sshsha.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
sshshare.c Move all extern declarations into header files. 2018-11-03 13:47:29 +00:00
sshsignals.h New system for handling SSH signals. 2018-10-21 10:02:10 +01:00
sshttymodes.h New system for handling SSH terminal modes. 2018-10-21 10:02:10 +01:00
sshverstring.c Start using C99 variadic macros. 2018-12-08 20:48:41 +00:00
sshzlib.c Move the ZLIB_STANDALONE main() into its own file. 2018-11-27 19:59:45 +00:00
storage.h Rework mungestr() and unmungestr(). 2018-11-03 13:45:00 +00:00
telnet.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
terminal.c Fix handling of backspace at beginning of line. 2018-12-08 16:12:05 +00:00
terminal.h Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
testback.c New abstraction 'Seat', to pass to backends. 2018-10-11 19:58:42 +01:00
testzlib.c Move the ZLIB_STANDALONE main() into its own file. 2018-11-27 19:59:45 +00:00
time.c Comment explaining location in top-level directory. 2005-02-07 15:23:45 +00:00
timing.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
tree234.c Remove some redundant variables and assignments. 2018-12-01 17:00:01 +00:00
tree234.h tree234.c: new search234() system. 2018-09-19 23:08:28 +01:00
version.c Show the git commit hash in local dev builds too. 2017-01-21 14:57:31 +00:00
version.h Server prep: pass "implementation name" to ssh_verstring_new. 2018-10-21 10:02:10 +01:00
wcwidth.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
wildcard.c Convert a lot of 'int' variables to 'bool'. 2018-11-03 13:45:00 +00:00
x11fwd.c x11fwd.c: Handle empty display number in authfile 2018-11-28 19:58:19 +00:00

This is the README for the source archive of PuTTY, a free Windows
and Unix Telnet and SSH client.

If you want to rebuild PuTTY from source, we provide a variety of
Makefiles and equivalents. (If you have fetched the source from
Git, you'll have to generate the Makefiles yourself -- see
below.)

There are various compile-time directives that you can use to
disable or modify certain features; it may be necessary to do this
in some environments. They are documented in `Recipe', and in
comments in many of the generated Makefiles.

For building on Windows:

 - windows/Makefile.vc is for command-line builds on MS Visual C++
   systems. Change into the `windows' subdirectory and type `nmake
   -f Makefile.vc' to build all the PuTTY binaries.

   As of 2017, we successfully compile PuTTY with both Visual Studio
   7 (2003) and Visual Studio 14 (2015), so our guess is that it will
   probably build with versions in between those as well.

   (The binaries from Visual Studio 14 are only compatible with
   Windows XP and up. Binaries from Visual Studio 7 ought to work
   with anything from Windows 95 onward.)

 - Inside the windows/MSVC subdirectory are MS Visual Studio project
   files for doing GUI-based builds of the various PuTTY utilities.
   These have been tested on Visual Studio 7 and 10.

   You should be able to build each PuTTY utility by loading the
   corresponding .dsp file in Visual Studio. For example,
   MSVC/putty/putty.dsp builds PuTTY itself, MSVC/plink/plink.dsp
   builds Plink, and so on.

 - windows/Makefile.mgw is for MinGW / Cygwin installations. Type
   `make -f Makefile.mgw' while in the `windows' subdirectory to
   build all the PuTTY binaries.

   MinGW and friends can lag behind other toolchains in their support
   for the Windows API. Compile-time levers are provided to exclude
   some features; the defaults are set appropriately for the
   'mingw-w64' cross-compiler provided with Ubuntu 14.04. If you are
   using an older toolchain, you may need to exclude more features;
   alternatively, you may find that upgrading to a recent version of
   the 'w32api' package helps.

 - windows/Makefile.lcc is for lcc-win32. Type `make -f
   Makefile.lcc' while in the `windows' subdirectory. (You will
   probably need to specify COMPAT=-DNO_MULTIMON.)

 - Inside the windows/DEVCPP subdirectory are Dev-C++ project
   files for doing GUI-based builds of the various PuTTY utilities.

The PuTTY team actively use Makefile.vc (with VC7/10) and Makefile.mgw
(with mingw32), so we'll probably notice problems with those
toolchains fairly quickly. Please report any problems with the other
toolchains mentioned above.

For building on Unix:

 - unix/configure is for Unix and GTK. If you don't have GTK, you
   should still be able to build the command-line utilities (PSCP,
   PSFTP, Plink, PuTTYgen) using this script. To use it, change into
   the `unix' subdirectory, run `./configure' and then `make'. Or you
   can do the same in the top-level directory (we provide a little
   wrapper that invokes configure one level down), which is more like
   a normal Unix source archive but doesn't do so well at keeping the
   per-platform stuff in each platform's subdirectory; it's up to you.

 - unix/Makefile.gtk and unix/Makefile.ux are for non-autoconfigured
   builds. These makefiles expect you to change into the `unix'
   subdirectory, then run `make -f Makefile.gtk' or `make -f
   Makefile.ux' respectively. Makefile.gtk builds all the programs but
   relies on Gtk, whereas Makefile.ux builds only the command-line
   utilities and has no Gtk dependence.

 - For the graphical utilities, any of Gtk+-1.2, Gtk+-2.0, and Gtk+-3.0
   should be supported. If you have more than one installed, you can
   manually specify which one you want by giving the option
   '--with-gtk=N' to the configure script where N is 1, 2, or 3.
   (The default is the newest available, of course.) In the absence
   of any Gtk version, the configure script will automatically
   construct a Makefile which builds only the command-line utilities;
   you can manually create this condition by giving configure the
   option '--without-gtk'.

 - pterm would like to be setuid or setgid, as appropriate, to permit
   it to write records of user logins to /var/run/utmp and
   /var/log/wtmp. (Of course it will not use this privilege for
   anything else, and in particular it will drop all privileges before
   starting up complex subsystems like GTK.) By default the makefile
   will not attempt to add privileges to the pterm executable at 'make
   install' time, but you can ask it to do so by running configure
   with the option '--enable-setuid=USER' or '--enable-setgid=GROUP'.

 - The Unix Makefiles have an `install' target. Note that by default
   it tries to install `man' pages; if you have fetched the source via
   Git then you will need to have built these using Halibut
   first - see below.

 - It's also possible to build the Windows version of PuTTY to run
   on Unix by using Winelib.  To do this, change to the `windows'
   directory and run `make -f Makefile.mgw CC=winegcc RC=wrc'.

All of the Makefiles are generated automatically from the file
`Recipe' by the Perl script `mkfiles.pl' (except for the Unix one,
which is generated by the `configure' script; mkfiles.pl only
generates the input to automake). Additions and corrections to Recipe,
mkfiles.pl and/or configure.ac are much more useful than additions and
corrections to the actual Makefiles, Makefile.am or Makefile.in.

The Unix `configure' script and its various requirements are generated
by the shell script `mkauto.sh', which requires GNU Autoconf, GNU
Automake, and Gtk; if you've got the source from Git rather
than using one of our source snapshots, you'll need to run this
yourself. The input file to Automake is generated by mkfiles.pl along
with all the rest of the makefiles, so you will need to run mkfiles.pl
and then mkauto.sh.

Documentation (in various formats including Windows Help and Unix
`man' pages) is built from the Halibut (`.but') files in the `doc'
subdirectory using `doc/Makefile'. If you aren't using one of our
source snapshots, you'll need to do this yourself. Halibut can be
found at <https://www.chiark.greenend.org.uk/~sgtatham/halibut/>.

The PuTTY home web site is

    https://www.chiark.greenend.org.uk/~sgtatham/putty/

If you want to send bug reports or feature requests, please read the
Feedback section of the web site before doing so. Sending one-line
reports saying `it doesn't work' will waste your time as much as
ours.

See the file LICENCE for the licence conditions.