relates to SSL_CTX flags and the use of "external" session caching. The
existing flag, "SSL_SESS_CACHE_NO_INTERNAL_LOOKUP" remains but is
supplemented with a complimentary flag, "SSL_SESS_CACHE_NO_INTERNAL_STORE".
The bitwise OR of the two flags is also defined as
"SSL_SESS_CACHE_NO_INTERNAL" and is the flag that should be used by most
applications wanting to implement session caching *entirely* by its own
provided callbacks. As the documented behaviour contradicted actual
behaviour up until recently, and since that point behaviour has itself been
inconsistent anyway, this change should not introduce any compatibility
problems. I've adjusted the relevant documentation to elaborate about how
this works.
Kudos to "Nadav Har'El" <nyh@math.technion.ac.il> for diagnosing these
anomalies and testing this patch for correctness.
PR: 311
Changes marked "(CHATS)" were sponsored by the Defense Advanced
Research Projects Agency (DARPA) and Air Force Research Laboratory,
Air Force Materiel Command, USAF, under agreement number
F30602-01-2-0537.
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:
First, it corrects a problem introduced in the last patch where the
kssl_map_enc() would intentionally return NULL for valid ENCTYPE
values. This was done to prevent verification of the kerberos 5
authenticator from being performed when Derived Key ciphers were
in use. Unfortunately, the authenticator verification routine was
not the only place that function was used. And it caused core dumps.
Second, it attempt to add to SSL_SESSION the Kerberos 5 Client
Principal Name.
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]
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.]
"doall" functions to using type-safe wrappers. As and where required, this
can be replaced by redeclaring the underlying callbacks to use the
underlying "void"-based prototypes (eg. if performance suffers from an
extra level of function invocation).
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.
Previously, the returned SSL_SESSION didn't have its reference count
incremented so the SSL_SESSION could be freed at any time causing
seg-faults if the pointer was subsequently used. Code that uses
SSL_get_session must now make a corresponding SSL_SESSION_free() call when
it is done to avoid memory leaks (or blocked up session caches).
Submitted By: Geoff Thorpe <geoff@eu.c2.net>
While modifying the sources, I found some inconsistencies on the use of
s->cert vs. s->session->sess_cert; I don't know if those could
really have caused problems, but possibly this is a proper bug-fix
and not just a clean-up.
