Maybe the patch below can help.
Disclaimer: this is just a POC, it is not thread safe (a single file is
used)!!!
You'll have to adjust that to your needs.
SSL_SESSION_print will write all the session infos (including the master
key) to the file.
If you need the master key only, you could use session->master_key (with
session->master_key_length).
Using the ssl_callback_info() (in the SSL_CB_HANDSHAKE_DONE state) allows
you to catch any (re)negotiation when finished.
Regards,
Yann.
Index: modules/ssl/ssl_engine_kernel.c
===================================================================
--- modules/ssl/ssl_engine_kernel.c (revision 1548486)
+++ modules/ssl/ssl_engine_kernel.c (working copy)
@@ -1989,6 +1989,15 @@ void ssl_callback_Info(MODSSL_INFO_CB_ARG_TYPE ssl
scr->reneg_state = RENEG_REJECT;
}
+ if ((where & SSL_CB_HANDSHAKE_DONE)) {
+ SSL_SESSION *session = SSL_get_session((SSL *)ssl);
+ if (session) {
+ BIO *bio = BIO_new_file("/path/to/sessions/file", "a");
+ SSL_SESSION_print(bio, session);
+ BIO_free(bio);
+ }
+ }
+
s = mySrvFromConn(c);
if (s && s->loglevel >= APLOG_DEBUG) {
log_tracing_state(ssl, c, s, where, rc);
[END OF PATCH]
On Fri, Dec 6, 2013 at 11:19 AM, Sebastian Biedermann <
biederm...@seceng.informatik.tu-darmstadt.de> wrote:
> Dear developers,
>
> I work on a research project about SSL security.
> Currently, I'm trying to identify and write the negotiated
> symmetric AES key of a session to a file just by modifying the
> apache2-2.4.6 source code. Until now, I was not able to identify
> and locate the variable which temporary stores this key.
>
> In apache2-2.4.6/modules/ssl/*mod_ssl.c*
> a new ssl connection is initiated in
> int *ssl_init_ssl_connection*(conn_rec *c, request_rec *r)
> and there are several structs, I guess one of them stores the key:
>
> SSLSrvConfigRec *sc;
> SSLConnRec *sslconn
> modssl_ctx_t *mctx;
> server_rec *server;
>
> Unfortunately, there is very less information about this on the Internet
> and I don't really know where to start.
> Can anyone give my a hint or tell me which variable stores the aes key?
>
> Thank you!
>
>
> --
> Sebastian
>
>
>
