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
The ec_name_to_curve and ec_curve_to_name functions shouldn't really
have had to exist at all: whenever any part of the PuTTY codebase
starts using sshecc.c, it's starting from an ssh_signkey or ssh_kex
pointer already found by some other means. So if we make sure not to
lose that pointer, we should never need to do any string-based lookups
to find the curve we want, and conversely, when we need to know the
name of our curve or our algorithm, we should be able to look it up as
a straightforward const char * starting from the algorithm pointer.
This commit cleans things up so that that is indeed what happens. The
ssh_signkey and ssh_kex structures defined in sshecc.c now have
'extra' fields containing pointers to all the necessary stuff;
ec_name_to_curve and ec_curve_to_name have been completely removed;
struct ec_curve has a string field giving the curve's name (but only
for those curves which _have_ a name exposed in the wire protocol,
i.e. the three NIST ones); struct ec_key keeps a pointer to the
ssh_signkey it started from, and uses that to remember the algorithm
name rather than reconstructing it from the curve. And I think I've
got rid of all the ad-hockery scattered around the code that switches
on curve->fieldBits or manually constructs curve names using stuff
like sprintf("nistp%d"); the only remaining switch on fieldBits
(necessary because that's the UI for choosing a curve in PuTTYgen) is
at least centralised into one place in sshecc.c.
One user-visible result is that the format of ed25519 host keys in the
registry has changed: there's now no curve name prefix on them,
because I think it's not really right to make up a name to use. So any
early adopters who've been using snapshot PuTTY in the last week will
be inconvenienced; sorry about that.
Not all of them, but the ones that don't get a 'void *key' parameter.
This means I can share methods between multiple ssh_signkey
structures, and still give those methods an easy way to find out which
public key method they're dealing with, by loading parameters from a
larger structure in which the ssh_signkey is the first element.
(In OO terms, I'm arranging that all static methods of my public key
classes get a pointer to the class vtable, to make up for not having a
pointer to the class instance.)
I haven't actually done anything with the new facility in this commit,
but it will shortly allow me to clean up the constant lookups by curve
name in the ECDSA code.
All the name strings in ssh_cipher, ssh_mac, ssh_hash, ssh_signkey
point to compile-time string literals, hence should obviously be const
char *.
Most of these const-correctness patches are just a mechanical job of
adding a 'const' in the one place you need it right now, and then
chasing the implications through the code adding further consts until
it compiles. But this one has actually shown up a bug: the 'algorithm'
output parameter in ssh2_userkey_loadpub was sometimes returning a
pointer to a string literal, and sometimes a pointer to dynamically
allocated memory, so callers were forced to either sometimes leak
memory or sometimes free a bad thing. Now it's consistently
dynamically allocated, and should be freed everywhere too.
There were ad-hoc functions for fingerprinting a bare key blob in both
cmdgen.c and pageant.c, not quite doing the same thing. Also, every
SSH-2 public key algorithm in the code base included a dedicated
fingerprint() method, which is completely pointless since SSH-2 key
fingerprints are computed in an algorithm-independent way (just hash
the standard-format public key blob), so each of those methods was
just duplicating the work of the public_blob() method with a less
general output mechanism.
Now sshpubk.c centrally provides an ssh2_fingerprint_blob() function
that does all the real work, plus an ssh2_fingerprint() function that
wraps it and deals with calling public_blob() to get something to
fingerprint. And the fingerprint() method has been completely removed
from ssh_signkey and all its implementations, and good riddance.
There was a fair amount of duplication between Windows and Unix
PuTTYgen, and some confusion over writing things to FILE * and
formatting them internally into strings. I think all the public-key
output code now lives in sshpubk.c, and there's only one copy of the
code to generate each format.
The rsakey_pubblob() and ssh2_userkey_loadpub() functions, which
expected to be given a private key file and load only the unencrypted
public half, now also cope with any of the public-only formats I know
about (SSH-1 only has one, whereas SSH-2 has the RFC 4716 format and
OpenSSH's one-line format) and return an appropriate public key blob
from each of those too.
cmdgen now supports this functionality, by permitting public key files
to be loaded and used by any operation that doesn't need the private
key: so you can convert back and forth between the SSH-2 public
formats, or list the file's fingerprint.
When I implemented reading and writing of the new format a couple of
weeks ago, I kept them strictly separate in the UI, so you have to ask
for the format you want when exporting. But in fact this is silly,
because not every key type can be saved in both formats, and OpenSSH
itself has the policy of using the old format for key types it can
handle, unless specifically asked to use the new one.
So I've now arranged that the key file format enum has three values
for OpenSSH: PEM, NEW and AUTO. Files being loaded are identified as
either PEM or NEW, which describe the two physical file formats. But
exporting UIs present either AUTO or NEW, where AUTO is the virtual
format meaning 'save in the old format if possible, otherwise the new
one'.
It's all very well for these two different formats to share a type
code as long as we're only loading them and not saving, but as soon as
we need to save one or the other, we'll need different type codes
after all.
This commit introduces the openssh_new_write() function, but for the
moment, it always returns failure.
I'd somehow managed to declare an enum in cmdgen.c with key types
OPENSSH and SSHCOM, and use it interchangeably with the one in ssh.h
with SSH_KEYTYPE_OPENSSH and SSH_KEYTYPE_SSHCOM.
It so happened that the relevant two enum values matched up! So this
hasn't caused a bug yet, but it's an accident waiting to happen. Fix
it before it does.
This provides support for ECDSA public keys, for both hosts and users,
and also ECDH key exchange. Supported curves are currently just the
three NIST curves required by RFC 5656.
The assertions I added to sshrand.c in r9930 are now justified,
because they were failing when cmdgen was used to convert a key into
either foreign private key file format - both the export functions
require random_byte() for one reason or another, and random_ref()
hadn't been called first.
[originally from svn r10117]
[r9930 == 33f485c1c3]
that the user really ought to know but that are not actually fatal to
continued operation of PuTTY or a single network connection.
[originally from svn r9932]
public key but not the private half, NULL out all the CRT-optimisation
fields as well as the private exponent pointer. Otherwise segfaults -
security-harmless, but annoying - can happen in freersakey() when we
notice they aren't null and try to free them.
[originally from svn r9705]
Well, at least across all command-line tools on both Windows and Unix,
and the GTK apps on Unix too. The Windows GUI apps fundamentally can't
write to standard output and it doesn't seem sensible to use message
boxes for these purposes :-)
[originally from svn r9673]
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]
as unsigned char. This means that passing in a bare char is incorrect on
systems where char is signed. Sprinkle some appropriate casts to prevent
this.
[originally from svn r8406]
takes a third argument which is TRUE if the file is being opened for
writing and wants to be created in such a way that it's readable
only to the owner. This is used when saving private keys.
While I'm here, I also use this option when writing session logs, on
the general principle that they probably contain _something_
sensitive.
The new argument is only supported on Unix, for the moment. (I think
writing owner-accessible-only files is the default on Windows.)
[originally from svn r7084]
(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]
- fix diagnostic if keyfile and '-t' both specified
- add diagnostic for generating a key but discarding the private part
- document '-q' option
[originally from svn r6750]
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]
for operations not performing decryption (e.g., "puttygen rsa1.ppk -L")
(A use for r6434 -- wasn't expecting that.)
[originally from svn r6436]
[r6434 == c14f259ba2]
* All the PuTTY tools for Windows and Unix now contain the fingerprints of
the Master Keys. The method for accessing them is crude but universal:
a new "-pgpfp" command-line option. (Except Unix PuTTYgen, which takes
"--pgpfp" just to be awkward.)
* Move the key policy discussion from putty-website/keys.html to
putty/doc/pgpkeys.but, and autogenerate the former from the latter.
Also tweak the text somewhat and include the fingerprints of the
Master Keys themselves.
(I've merged the existing autogeneration scripts into a single new
one; I've left the old scripts and keys.html around until such time
as the webmonster reviews the changes and plumbs in the new script;
he should remove the old files then.)
[originally from svn r5524]
[this svn revision also touched putty-website]
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]
- will now display a reason when it fails to load a key
- uses existing error return from native keys
- import.c had a lot of error descriptions which weren't going anywhere;
since the strings are probably taking up space in the binary, we
may as well use them
[originally from svn r5408]
Fixes crashes when time() returns (time_t)-1 on Windows by using the
Win32 GetLocalTime() function. (The Unix implementation still just
uses time() and localtime().)
[originally from svn r5086]
timing.c, and hence takes its own responsibility for calling
noise_regular() at regular intervals. Again, this means it will be
called consistently in _all_ the SSH-speaking tools, not just those
in which I remembered to call it!
[originally from svn r4913]
on Linux, but the (very few) platform-specific bits are already
abstracted out of the main code, so it should port to other
platforms with a minimum of fuss.
[originally from svn r3762]
