Both have per-SSL_CTX defaults.
These new values can be set by calling SSL[_CTX]_[callback_]ctrl
with codes SSL_CTRL_SET_MSG_CALLBACK and SSL_CTRL_SET_MSG_CALLBACK_ARG.
So far, the callback is never actually called.
Also rearrange some SSL_CTX struct members (some exist just in
SSL_CTXs, others are defaults for SSLs and are either copied
during SSL_new, or used if the value in the SSL is not set;
these three classes of members were not in a logical order),
and add some missing assignments to SSL_dup.
See the commit log message for that for more information.
NB: X509_STORE_CTX's use of "ex_data" support was actually misimplemented
(initialisation by "memset" won't/can't/doesn't work). This fixes that but
requires that X509_STORE_CTX_init() be able to handle errors - so its
prototype has been changed to return 'int' rather than 'void'. All uses of
that function throughout the source code have been tracked down and
adjusted.
setting stack (actually, array) values in ex_data. So only increment the
global counters if the underlying CRYPTO_get_ex_new_index() call succeeds.
This change doesn't make "ex_data" right (see the comment at the head of
ex_data.c to know why), but at least makes the source code marginally less
frustrating.
His comments are:
. adds use of replay cache to protect against replay attacks
. adds functions kssl_tgt_is_available() and
kssl_keytab_is_available() which are used within s3_lib.c
and ssl_lib.c to determine at runtime whether or not
KRB5 ciphers can be supported during the current session.
an SSL_CTX's session cache, it is necessary to compare the ssl_version at
the same time (a conflict is defined, courtesy of SSL_SESSION_cmp(), as a
matching id/id_length pair and a matching ssl_version). However, the
SSL_SESSION that will result from the current negotiation does not
necessarily have the same ssl version as the "SSL_METHOD" in use by the
SSL_CTX - part of the work in a handshake is to agree on an ssl version!
This is fixed by having the check function accept an SSL pointer rather
than the SSL_CTX it belongs to.
[Thanks to Lutz for illuminating the full extent of my stupidity]
the ID will be padded out to 16 bytes if the callback attempted to generate
a shorter one. The problem is that the uniqueness checking function used in
callbacks may mistakenly think a 9-byte ID is unique when in fact its
padded 16-byte version is not. This makes the checking function detect
SSLv2 cases, and ensures the padded form is checked rather than the shorter
one passed by the callback.
SSL/TLS session IDs in a server. According to RFC2246, the session ID is an
arbitrary value chosen by the server. It can be useful to have some control
over this "arbitrary value" so as to choose it in ways that can aid in
things like external session caching and balancing (eg. clustering). The
default session ID generation is to fill the ID with random data.
The callback used by default is built in to ssl_sess.c, but registering a
callback in an SSL_CTX or in a particular SSL overrides this. BTW: SSL
callbacks will override SSL_CTX callbacks, and a new SSL structure inherits
any callback set in its 'parent' SSL_CTX. The header comments describe how
this mechanism ticks, and source code comments describe (hopefully) why it
ticks the way it does.
Man pages are on the way ...
[NB: Lutz was also hacking away and helping me to figure out how best to do
this.]
DECLARE/IMPLEMENT macros now exist to create type (and prototype) safe
wrapper functions that avoid the use of function pointer casting yet retain
type-safety for type-specific callbacks. However, most of the usage within
OpenSSL itself doesn't really require the extra function because the hash
and compare callbacks are internal functions declared only for use by the
hash table. So this change catches all those cases and reimplements the
functions using the base-level LHASH prototypes and does per-variable
casting inside those functions to convert to the appropriate item type.
The exception so far is in ssl_lib.c where the hash and compare callbacks
are not static - they're exposed in ssl.h so their prototypes should not be
changed. In this last case, the IMPLEMENT_LHASH_*** macros have been left
intact.
casts) used in the lhash code are about as horrible and evil as they can
be. For starters, the callback prototypes contain empty parameter lists.
Yuck.
This first change defines clearer prototypes - including "typedef"'d
function pointer types to use as "hash" and "compare" callbacks, as well as
the callbacks passed to the lh_doall and lh_doall_arg iteration functions.
Now at least more explicit (and clear) casting is required in all of the
dependant code - and that should be included in this commit.
The next step will be to hunt down and obliterate some of the function
pointer casting being used when it's not necessary - a particularly evil
variant exists in the implementation of lh_doall.
like Malloc, Realloc and especially Free conflict with already existing names
on some operating systems or other packages. That is reason enough to change
the names of the OpenSSL memory allocation macros to something that has a
better chance of being unique, like prepending them with OPENSSL_.
This change includes all the name changes needed throughout all C files.
yet tighter, and also put some heat on the rest of the library by
insisting (correctly) that compare callbacks used in stacks are prototyped
with "const" parameters. This has led to a depth-first explosion of
compiler warnings in the code where 1 constification has led to 3 or 4
more. Fortunately these have all been resolved to completion and the code
seems cleaner as a result - in particular many of the _cmp() functions
should have been prototyped with "const"s, and now are. There was one
little problem however;
X509_cmp() should by rights compare "const X509 *" pointers, and it is now
declared as such. However, it's internal workings can involve
recalculating hash values and extensions if they have not already been
setup. Someone with a more intricate understanding of the flow control of
X509 might be able to tighten this up, but for now - this seemed the
obvious place to stop the "depth-first" constification of the code by
using an evil cast (they have migrated all the way here from safestack.h).
Fortunately, this is the only place in the code where this was required
to complete these type-safety changes, and it's reasonably clear and
commented, and seemed the least unacceptable of the options. Trying to
take the constification further ends up exploding out considerably, and
indeed leads directly into generalised ASN functions which are not likely
to cooperate well with this.
designed for that. This removes the potential error to mix data and
function pointers.
Please note that I'm a little unsure how incorrect calls to the old
ctrl functions should be handled, in som cases. I currently return 0
and that's it, but it may be more correct to generate a genuine error
in those cases.
non-function pointers to function pointers and vice versa.
The current solution is to have unions that describe the
conversion we want to do, and gives us the ability to extract
the type of data we want.
The current solution is a quick fix, and can probably be made
in a more general or elegant way.
