This clears up another large pile of clutter at the top level, and in
the process, allows me to rename source files to things that don't all
have that annoying 'ssh' prefix at the top.
This brings various concrete advantages over the previous system:
- consistent support for out-of-tree builds on all platforms
- more thorough support for Visual Studio IDE project files
- support for Ninja-based builds, which is particularly useful on
Windows where the alternative nmake has no parallel option
- a really simple set of build instructions that work the same way on
all the major platforms (look how much shorter README is!)
- better decoupling of the project configuration from the toolchain
configuration, so that my Windows cross-building doesn't need
(much) special treatment in CMakeLists.txt
- configure-time tests on Windows as well as Linux, so that a lot of
ad-hoc #ifdefs second-guessing a particular feature's presence from
the compiler version can now be replaced by tests of the feature
itself
Also some longer-term software-engineering advantages:
- other people have actually heard of CMake, so they'll be able to
produce patches to the new build setup more easily
- unlike the old mkfiles.pl, CMake is not my personal problem to
maintain
- most importantly, mkfiles.pl was just a horrible pile of
unmaintainable cruft, which even I found it painful to make changes
to or to use, and desperately needed throwing in the bin. I've
already thrown away all the variants of it I had in other projects
of mine, and was only delaying this one so we could make the 0.75
release branch first.
This change comes with a noticeable build-level restructuring. The
previous Recipe worked by compiling every object file exactly once,
and then making each executable by linking a precisely specified
subset of the same object files. But in CMake, that's not the natural
way to work - if you write the obvious command that puts the same
source file into two executable targets, CMake generates a makefile
that compiles it once per target. That can be an advantage, because it
gives you the freedom to compile it differently in each case (e.g.
with a #define telling it which program it's part of). But in a
project that has many executable targets and had carefully contrived
to _never_ need to build any module more than once, all it does is
bloat the build time pointlessly!
To avoid slowing down the build by a large factor, I've put most of
the modules of the code base into a collection of static libraries
organised vaguely thematically (SSH, other backends, crypto, network,
...). That means all those modules can still be compiled just once
each, because once each library is built it's reused unchanged for all
the executable targets.
One upside of this library-based structure is that now I don't have to
manually specify exactly which objects go into which programs any more
- it's enough to specify which libraries are needed, and the linker
will figure out the fine detail automatically. So there's less
maintenance to do in CMakeLists.txt when the source code changes.
But that reorganisation also adds fragility, because of the trad Unix
linker semantics of walking along the library list once each, so that
cyclic references between your libraries will provoke link errors. The
current setup builds successfully, but I suspect it only just manages
it.
(In particular, I've found that MinGW is the most finicky on this
score of the Windows compilers I've tried building with. So I've
included a MinGW test build in the new-look Buildscr, because
otherwise I think there'd be a significant risk of introducing
MinGW-only build failures due to library search order, which wasn't a
risk in the previous library-free build organisation.)
In the longer term I hope to be able to reduce the risk of that, via
gradual reorganisation (in particular, breaking up too-monolithic
modules, to reduce the risk of knock-on references when you included a
module for function A and it also contains function B with an
unsatisfied dependency you didn't really need). Ideally I want to
reach a state in which the libraries all have sensibly described
purposes, a clearly documented (partial) order in which they're
permitted to depend on each other, and a specification of what stubs
you have to put where if you're leaving one of them out (e.g.
nocrypto) and what callbacks you have to define in your non-library
objects to satisfy dependencies from things low in the stack (e.g.
out_of_memory()).
One thing that's gone completely missing in this migration,
unfortunately, is the unfinished MacOS port linked against Quartz GTK.
That's because it turned out that I can't currently build it myself,
on my own Mac: my previous installation of GTK had bit-rotted as a
side effect of an Xcode upgrade, and I haven't yet been able to
persuade jhbuild to make me a new one. So I can't even build the MacOS
port with the _old_ makefiles, and hence, I have no way of checking
that the new ones also work. I hope to bring that port back to life at
some point, but I don't want it to block the rest of this change.
Up until now, it's been a variadic _function_, whose argument list
consists of 'const char *' ASCIZ strings to concatenate, terminated by
one containing a null pointer. Now, that function is dupcat_fn(), and
it's wrapped by a C99 variadic _macro_ called dupcat(), which
automatically suffixes the null-pointer terminating argument.
This has three benefits. Firstly, it's just less effort at every call
site. Secondly, it protects against the risk of accidentally leaving
off the NULL, causing arbitrary words of stack memory to be
dereferenced as char pointers. And thirdly, it protects against the
more subtle risk of writing a bare 'NULL' as the terminating argument,
instead of casting it explicitly to a pointer. That last one is
necessary because C permits the macro NULL to expand to an integer
constant such as 0, so NULL by itself may not have pointer type, and
worse, it may not be marshalled in a variadic argument list in the
same way as a pointer. (For example, on a 64-bit machine it might only
occupy 32 bits. And yet, on another 64-bit platform, it might work
just fine, so that you don't notice the mistake!)
I was inspired to do this by happening to notice one of those bare
NULL terminators, and thinking I'd better check if there were any
more. Turned out there were quite a few. Now there are none.
The number of people has been steadily increasing who read our source
code with an editor that thinks tab stops are 4 spaces apart, as
opposed to the traditional tty-derived 8 that the PuTTY code expects.
So I've been wondering for ages about just fixing it, and switching to
a spaces-only policy throughout the code. And I recently found out
about 'git blame -w', which should make this change not too disruptive
for the purposes of source-control archaeology; so perhaps now is the
time.
While I'm at it, I've also taken the opportunity to remove all the
trailing spaces from source lines (on the basis that git dislikes
them, and is the only thing that seems to have a strong opinion one
way or the other).
Apologies to anyone downstream of this code who has complicated patch
sets to rebase past this change. I don't intend it to be needed again.
Fill in all the function pointers for 3rd party Windows GSS DLLs, not
just some of them. These were missed out when GSS key exchange was added
in d515e4f1a3.
The specific thing that's strange about it is that it's _not_ an error
even though the compiler is quite justified in being suspicious about
it! The MS APIs define two different structures to have identical
formats.
This is a heavily edited (by me) version of a patch originally due to
Nico Williams and Viktor Dukhovni. Their comments:
* Don't delegate credentials when rekeying unless there's a new TGT
or the old service ticket is nearly expired.
* Check for the above conditions more frequently (every two minutes
by default) and rekey when we would delegate credentials.
* Do not rekey with very short service ticket lifetimes; some GSSAPI
libraries may lose the race to use an almost expired ticket. Adjust
the timing of rekey checks to try to avoid this possibility.
My further comments:
The most interesting thing about this patch to me is that the use of
GSS key exchange causes a switch over to a completely different model
of what host keys are for. This comes from RFC 4462 section 2.1: the
basic idea is that when your session is mostly bidirectionally
authenticated by the GSSAPI exchanges happening in initial kex and
every rekey, host keys become more or less vestigial, and their
remaining purpose is to allow a rekey to happen if the requirements of
the SSH protocol demand it at an awkward moment when the GSS
credentials are not currently available (e.g. timed out and haven't
been renewed yet). As such, there's no need for host keys to be
_permanent_ or to be a reliable identifier of a particular host, and
RFC 4462 allows for the possibility that they might be purely
transient and only for this kind of emergency fallback purpose.
Therefore, once PuTTY has done a GSS key exchange, it disconnects
itself completely from the permanent host key cache functions in
storage.h, and instead switches to a _transient_ host key cache stored
in memory with the lifetime of just that SSH session. That cache is
populated with keys received from the server as a side effect of GSS
kex (via the optional SSH2_MSG_KEXGSS_HOSTKEY message), and used if
later in the session we have to fall back to a non-GSS key exchange.
However, in practice servers we've tested against do not send a host
key in that way, so we also have a fallback method of populating the
transient cache by triggering an immediate non-GSS rekey straight
after userauth (reusing the code path we also use to turn on OpenSSH
delayed encryption without the race condition).
These include an unused variable left over from the command-line
refactoring; an explicit referencing of the module handle for
sspicli.dll which we really do deliberately load and then don't
(directly) use; a missing pointer-type cast in the Windows handle
socket code; and two 32/64 bit integer size mismatches in the types of
functions I was importing from system API DLLs.
The last of those are a bit worrying, and suggest to me that after
going to all that trouble to add type-checking of those runtime
imports in commit 49fb598b0, I might have only checked the resulting
compiler output in a 32-bit build and not a 64-bit one. Oops!
64-bit PuTTY should be loading gssapi64.dll, not gssapi32.dll. (In
contrast to the Windows system API DLLs, such as secur32.dll which is
also mentioned in the same source file; those keep the "32" in their
name whether we're in Win32 or Win64.)
This gives me an extra safety-check against having mistyped one of the
function prototypes that we load at run time from DLLs: we verify that
the typedef we defined based on the prototype in our source code
matches the type of the real function as declared in the Windows
headers.
This was an idea I had while adding a pile of further functions using
this mechanism. It didn't catch any errors (either in the new
functions or in the existing collection), but that's no reason not to
keep it anyway now that I've thought of it!
In VS2015, this automated type-check works for most functions, but a
couple manage to break it. SetCurrentProcessExplicitAppUserModelID in
winjump.c can't be type-checked, because including <shobjidl.h> where
that function is declared would also bring in a load of other stuff
that conflicts with the painful manual COM declarations in winjump.c.
(That stuff could probably be removed now we're on an up-to-date
Visual Studio, on the other hand, but that's a separate chore.) And
gai_strerror, used in winnet.c, does _have_ an implementation in a
DLL, but the header files like to provide an inline version with a
different calling convention, which defeats this error-checking trick.
And in the older VS2003 that we still precautionarily build with,
several more type-checks have to be #ifdeffed out because the
functions they check against just aren't there at all.
gssapi32.dll from MIT Kerberos as well as from Heimdal both load
further DLLs from their installation directories.
[SGT: I polished the original patch a bit, in particular replacing
manual memory allocation with dup_mb_to_wc. This required a Recipe
change to link miscucs.c and winucs.c into more of the tools.]
These ones are stylistic rather than potential bugs: mostly signedness
of char pointers in cases where they clearly aren't going to cause the
wrong thing to actually happen, and one thing in winsecur.c where
clang would have preferred an extra pair of braces around some
initialisers but it's legal with or without. But since some of clang's
warnings turn out to be quite useful, it seems worth silencing these
harmless ones so as to be able to see the rest.
Having found a lot of unfixed constness issues in recent development,
I thought perhaps it was time to get proactive, so I compiled the
whole codebase with -Wwrite-strings. That turned up a huge load of
const problems, which I've fixed in this commit: the Unix build now
goes cleanly through with -Wwrite-strings, and the Windows build is as
close as I could get it (there are some lingering issues due to
occasional Windows API functions like AcquireCredentialsHandle not
having the right constness).
Notable fallout beyond the purely mechanical changing of types:
- the stuff saved by cmdline_save_param() is now explicitly
dupstr()ed, and freed in cmdline_run_saved.
- I couldn't make both string arguments to cmdline_process_param()
const, because it intentionally writes to one of them in the case
where it's the argument to -pw (in the vain hope of being at least
slightly friendly to 'ps'), so elsewhere I had to temporarily
dupstr() something for the sake of passing it to that function
- I had to invent a silly parallel version of const_cmp() so I could
pass const string literals in to lookup functions.
- stripslashes() in pscp.c and psftp.c has the annoying strchr nature
'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]
information about where to put items that aren't mentioned in the
saved configuration. So far the only nontrivial use I've made of this
facility is to default to placing KEX_RSA just above KEX_WARN in the
absence of any other information, which should fix
'ssh2-rsa-kex-pref'.
While I'm here I've rewritten wprefs() on general principles to remove
the needless length limit, since I was touching it anyway. The length
limit is still in gprefs (but I've lengthened it just in case).
[originally from svn r9181]
are now loaded from standard locations (system32 for SSPI, the
registry-stored MIT KfW install location for KfW) rather than using
the risky default DLL search path; I've therefore also added an
option to manually specify a GSS DLL we haven't heard of (which
should in principle Just Work provided it supports proper GSS-API as
specified in the RFC). The same option exists on Unix too, because
it seemed like too useful an idea to reserve to Windows. In
addition, GSSAPI is now documented, and also (unfortunately) its GUI
configuration has been moved out into a sub-subpanel on the grounds
that it was too big to fit in Auth.
[originally from svn r9003]
called load_system32_dll() which constructs a full pathname for the
DLL using GetSystemDirectory.
The only DLL load not covered by this change is the one for
gssapi32.dll, because that one's not in the system32 directory.
[originally from svn r8993]
reorganises the GSSAPI support so that it handles alternative
implementations of the GSS-API. In particular, this means PuTTY can
now talk to MIT Kerberos for Windows instead of being limited to
SSPI. I don't know for sure whether further tweaking will be needed
(to the UI, most likely, or to automatic selection of credentials),
but testing reports suggest it's now at least worth committing to
trunk to get it more widely tested.
[originally from svn r8952]
linking on Windows into a single global one, which can cope with function
renaming. Intended to enable eventual removal of ANSI-specific DoSomethingA
references (although I've not removed any).
[originally from svn r8738]
directly. Fixes a build failure involving name clashes between
winsock2.h and winsock.h, which had somehow managed to get included
in succession.
[originally from svn r8332]
ourselves, but on Unix then assumed it was compatible with the system's
gss_buffer_desc, which wasn't the case on LP64 systems. Now, on Unix
we make Ssh_gss_buf into an alias for gss_buffer_desc, though we keep
something similar to the existing behaviour on Windows. This requires
renaming a couple of the fields in Ssh_gss_buf, and hence fixing all
the references.
Tested on Linux (MIT Kerberos) and Solaris. Compiled on NetBSD (Heimdal).
Not tested on Windows because neither mingw32 nor winegcc worked out of the
box for me. I think the Windows changes are all syntactic, though, so
if this compiles it should work no worse than before.
[originally from svn r8326]
