upload http

JIRA: BOTTLENECK-10

Change-Id: I7598427ff904df438ce77c2819ee48ac75ffa8da
Signed-off-by: hongbotian <hongbo.tianhongbo@huawei.com>

1 files changed, 1876 insertions, 0 deletions

diff --git a/rubbos/app/httpd-2.0.64/modules/ssl/ssl_engine_kernel.c b/rubbos/app/httpd-2.0.64/modules/ssl/ssl_engine_kernel.c
new file mode 100644
index 00000000..60133f7c
--- /dev/null
+++ b/rubbos/app/httpd-2.0.64/modules/ssl/ssl_engine_kernel.c
@@ -0,0 +1,1876 @@
+/* Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*                      _             _
+ *  _ __ ___   ___   __| |    ___ ___| |  mod_ssl
+ * | '_ ` _ \ / _ \ / _` |   / __/ __| |  Apache Interface to OpenSSL
+ * | | | | | | (_) | (_| |   \__ \__ \ |
+ * |_| |_| |_|\___/ \__,_|___|___/___/_|
+ *                      |_____|
+ *  ssl_engine_kernel.c
+ *  The SSL engine kernel
+ */
+                             /* ``It took me fifteen years to discover
+                                  I had no talent for programming, but
+                                  I couldn't give it up because by that
+                                  time I was too famous.''
+                                            -- Unknown                */
+#include "mod_ssl.h"
+
+static void ssl_configure_env(request_rec *r, SSLConnRec *sslconn);
+ 
+/* Perform a speculative (and non-blocking) read from the connection
+ * filters for the given request, to determine whether there is any
+ * pending data to read.  Return non-zero if there is, else zero. */
+static int has_buffered_data(request_rec *r) 
+{
+    apr_bucket_brigade *bb;
+    apr_off_t len;
+    apr_status_t rv;
+    int result;
+
+    bb = apr_brigade_create(r->pool, r->connection->bucket_alloc);
+
+    rv = ap_get_brigade(r->connection->input_filters, bb, AP_MODE_SPECULATIVE,
+                        APR_NONBLOCK_READ, 1);
+    result = rv == APR_SUCCESS
+        && apr_brigade_length(bb, 1, &len) == APR_SUCCESS
+        && len > 0;
+
+    apr_brigade_destroy(bb);
+
+    return result;
+}
+
+/*
+ *  Post Read Request Handler
+ */
+int ssl_hook_ReadReq(request_rec *r)
+{
+    SSLConnRec *sslconn = myConnConfig(r->connection);
+    SSL *ssl;
+
+    if (!sslconn) {
+        return DECLINED;
+    }
+
+    if (sslconn->non_ssl_request) {
+        const char *errmsg;
+        char *thisurl;
+        char *thisport = "";
+        int port = ap_get_server_port(r);
+
+        if (!ap_is_default_port(port, r)) {
+            thisport = apr_psprintf(r->pool, ":%u", port);
+        }
+
+        thisurl = ap_escape_html(r->pool,
+                                 apr_psprintf(r->pool, "https://%s%s/",
+                                              ap_get_server_name(r),
+                                              thisport));
+
+        errmsg = apr_psprintf(r->pool,
+                              "Reason: You're speaking plain HTTP "
+                              "to an SSL-enabled server port.<br />\n"
+                              "Instead use the HTTPS scheme to access "
+                              "this URL, please.<br />\n"
+                              "<blockquote>Hint: "
+                              "<a href=\"%s\"><b>%s</b></a></blockquote>",
+                              thisurl, thisurl);
+
+        apr_table_setn(r->notes, "error-notes", errmsg);
+
+        /* Now that we have caught this error, forget it. we are done
+         * with using SSL on this request.
+         */
+        sslconn->non_ssl_request = 0;
+        
+
+        return HTTP_BAD_REQUEST;
+    }
+
+    /*
+     * Get the SSL connection structure and perform the
+     * delayed interlinking from SSL back to request_rec
+     */
+    ssl = sslconn->ssl;
+    if (!ssl) {
+        return DECLINED;
+    }
+    SSL_set_app_data2(ssl, r);
+
+    /*
+     * Log information about incoming HTTPS requests
+     */
+    if (r->server->loglevel >= APLOG_INFO && ap_is_initial_req(r)) {
+        ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
+                     "%s HTTPS request received for child %ld (server %s)",
+                     (r->connection->keepalives <= 0 ?
+                     "Initial (No.1)" :
+                     apr_psprintf(r->pool, "Subsequent (No.%d)",
+                                  r->connection->keepalives+1)),
+                     r->connection->id,
+                     ssl_util_vhostid(r->pool, r->server));
+    }
+
+    /* SetEnvIf ssl-*-shutdown flags can only be per-server,
+     * so they won't change across keepalive requests
+     */
+    if (sslconn->shutdown_type == SSL_SHUTDOWN_TYPE_UNSET) {
+        ssl_configure_env(r, sslconn);
+    }
+
+    return DECLINED;
+}
+
+/*
+ * Move SetEnvIf information from request_rec to conn_rec/BUFF
+ * to allow the close connection handler to use them.
+ */
+
+static void ssl_configure_env(request_rec *r, SSLConnRec *sslconn)
+{
+    int i;
+    const apr_array_header_t *arr = apr_table_elts(r->subprocess_env);
+    const apr_table_entry_t *elts = (const apr_table_entry_t *)arr->elts;
+
+    sslconn->shutdown_type = SSL_SHUTDOWN_TYPE_STANDARD;
+
+    for (i = 0; i < arr->nelts; i++) {
+        const char *key = elts[i].key;
+
+        switch (*key) {
+          case 's':
+            /* being case-sensitive here.
+             * and not checking for the -shutdown since these are the only
+             * SetEnvIf "flags" we support
+             */
+            if (!strncmp(key+1, "sl-", 3)) {
+                key += 4;
+                if (!strncmp(key, "unclean", 7)) {
+                    sslconn->shutdown_type = SSL_SHUTDOWN_TYPE_UNCLEAN;
+                }
+                else if (!strncmp(key, "accurate", 8)) {
+                    sslconn->shutdown_type = SSL_SHUTDOWN_TYPE_ACCURATE;
+                }
+                return; /* should only ever be one ssl-*-shutdown */
+            }
+            break;
+        }
+    }
+}
+
+/*
+ *  Access Handler
+ */
+int ssl_hook_Access(request_rec *r)
+{
+    SSLDirConfigRec *dc = myDirConfig(r);
+    SSLSrvConfigRec *sc = mySrvConfig(r->server);
+    SSLConnRec *sslconn = myConnConfig(r->connection);
+    SSL *ssl            = sslconn ? sslconn->ssl : NULL;
+    SSL_CTX *ctx = NULL;
+    apr_array_header_t *requires;
+    ssl_require_t *ssl_requires;
+    char *cp;
+    int ok, i;
+    BOOL renegotiate = FALSE, renegotiate_quick = FALSE;
+    X509 *cert;
+    X509 *peercert;
+    X509_STORE *cert_store = NULL;
+    X509_STORE_CTX cert_store_ctx;
+    STACK_OF(SSL_CIPHER) *cipher_list_old = NULL, *cipher_list = NULL;
+    SSL_CIPHER *cipher = NULL;
+    int depth, verify_old, verify, n;
+
+    if (ssl) {
+        ctx = SSL_get_SSL_CTX(ssl);
+    }
+
+    /*
+     * Support for SSLRequireSSL directive
+     */
+    if (dc->bSSLRequired && !ssl) {
+        ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, 
+                      "access to %s failed, reason: %s",
+                      r->filename, "SSL connection required");
+
+        /* remember forbidden access for strict require option */
+        apr_table_setn(r->notes, "ssl-access-forbidden", "1");
+
+        return HTTP_FORBIDDEN;
+    }
+
+    /*
+     * Check to see whether SSL is in use; if it's not, then no
+     * further access control checks are relevant.  (the test for
+     * sc->enabled is probably strictly unnecessary)
+     */
+    if (!sc->enabled || !ssl) {
+        return DECLINED;
+    }
+
+    /*
+     * Support for per-directory reconfigured SSL connection parameters.
+     *
+     * This is implemented by forcing an SSL renegotiation with the
+     * reconfigured parameter suite. But Apache's internal API processing
+     * makes our life very hard here, because when internal sub-requests occur
+     * we nevertheless should avoid multiple unnecessary SSL handshakes (they
+     * require extra network I/O and especially time to perform). 
+     * 
+     * But the optimization for filtering out the unnecessary handshakes isn't
+     * obvious and trivial.  Especially because while Apache is in its
+     * sub-request processing the client could force additional handshakes,
+     * too. And these take place perhaps without our notice. So the only
+     * possibility is to explicitly _ask_ OpenSSL whether the renegotiation
+     * has to be performed or not. It has to performed when some parameters
+     * which were previously known (by us) are not those we've now
+     * reconfigured (as known by OpenSSL) or (in optimized way) at least when
+     * the reconfigured parameter suite is stronger (more restrictions) than
+     * the currently active one.
+     */
+
+    /*
+     * Override of SSLCipherSuite
+     *
+     * We provide two options here:
+     *
+     * o The paranoid and default approach where we force a renegotiation when
+     *   the cipher suite changed in _any_ way (which is straight-forward but
+     *   often forces renegotiations too often and is perhaps not what the
+     *   user actually wanted).
+     *
+     * o The optimized and still secure way where we force a renegotiation
+     *   only if the currently active cipher is no longer contained in the
+     *   reconfigured/new cipher suite. Any other changes are not important
+     *   because it's the servers choice to select a cipher from the ones the
+     *   client supports. So as long as the current cipher is still in the new
+     *   cipher suite we're happy. Because we can assume we would have
+     *   selected it again even when other (better) ciphers exists now in the
+     *   new cipher suite. This approach is fine because the user explicitly
+     *   has to enable this via ``SSLOptions +OptRenegotiate''. So we do no
+     *   implicit optimizations.
+     */
+    if (dc->szCipherSuite) {
+        /* remember old state */
+
+        if (dc->nOptions & SSL_OPT_OPTRENEGOTIATE) {
+            cipher = SSL_get_current_cipher(ssl);
+        }
+        else {
+            cipher_list_old = (STACK_OF(SSL_CIPHER) *)SSL_get_ciphers(ssl);
+
+            if (cipher_list_old) {
+                cipher_list_old = sk_SSL_CIPHER_dup(cipher_list_old);
+            }
+        }
+
+        /* configure new state */
+        if (!modssl_set_cipher_list(ssl, dc->szCipherSuite)) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0,
+                         r->server,
+                         "Unable to reconfigure (per-directory) "
+                         "permitted SSL ciphers");
+            ssl_log_ssl_error(APLOG_MARK, APLOG_ERR, r->server);
+
+            if (cipher_list_old) {
+                sk_SSL_CIPHER_free(cipher_list_old);
+            }
+
+            return HTTP_FORBIDDEN;
+        }
+
+        /* determine whether a renegotiation has to be forced */
+        cipher_list = (STACK_OF(SSL_CIPHER) *)SSL_get_ciphers(ssl);
+
+        if (dc->nOptions & SSL_OPT_OPTRENEGOTIATE) {
+            /* optimized way */
+            if ((!cipher && cipher_list) ||
+                (cipher && !cipher_list))
+            {
+                renegotiate = TRUE;
+            }
+            else if (cipher && cipher_list &&
+                     (sk_SSL_CIPHER_find(cipher_list, cipher) < 0))
+            {
+                renegotiate = TRUE;
+            }
+        }
+        else {
+            /* paranoid way */
+            if ((!cipher_list_old && cipher_list) ||
+                (cipher_list_old && !cipher_list))
+            {
+                renegotiate = TRUE;
+            }
+            else if (cipher_list_old && cipher_list) {
+                for (n = 0;
+                     !renegotiate && (n < sk_SSL_CIPHER_num(cipher_list));
+                     n++)
+                {
+                    SSL_CIPHER *value = sk_SSL_CIPHER_value(cipher_list, n);
+
+                    if (sk_SSL_CIPHER_find(cipher_list_old, value) < 0) {
+                        renegotiate = TRUE;
+                    }
+                }
+
+                for (n = 0;
+                     !renegotiate && (n < sk_SSL_CIPHER_num(cipher_list_old));
+                     n++)
+                {
+                    SSL_CIPHER *value = sk_SSL_CIPHER_value(cipher_list_old, n);
+
+                    if (sk_SSL_CIPHER_find(cipher_list, value) < 0) {
+                        renegotiate = TRUE;
+                    }
+                }
+            }
+        }
+
+        /* cleanup */
+        if (cipher_list_old) {
+            sk_SSL_CIPHER_free(cipher_list_old);
+        }
+
+        /* tracing */
+        if (renegotiate) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
+                         "Reconfigured cipher suite will force renegotiation");
+        }
+    }
+
+    /*
+     * override of SSLVerifyDepth
+     *
+     * The depth checks are handled by us manually inside the verify callback
+     * function and not by OpenSSL internally (and our function is aware of
+     * both the per-server and per-directory contexts). So we cannot ask
+     * OpenSSL about the currently verify depth. Instead we remember it in our
+     * ap_ctx attached to the SSL* of OpenSSL.  We've to force the
+     * renegotiation if the reconfigured/new verify depth is less than the
+     * currently active/remembered verify depth (because this means more
+     * restriction on the certificate chain).
+     */
+    if (dc->nVerifyDepth != UNSET) {
+        /* XXX: doesnt look like sslconn->verify_depth is actually used */
+        if (!(n = sslconn->verify_depth)) {
+            sslconn->verify_depth = n = sc->server->auth.verify_depth;
+        }
+
+        /* determine whether a renegotiation has to be forced */
+        if (dc->nVerifyDepth < n) {
+            renegotiate = TRUE;
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
+                         "Reduced client verification depth will force "
+                         "renegotiation");
+        }
+    }
+
+    /*
+     * override of SSLVerifyClient
+     *
+     * We force a renegotiation if the reconfigured/new verify type is
+     * stronger than the currently active verify type. 
+     *
+     * The order is: none << optional_no_ca << optional << require
+     *
+     * Additionally the following optimization is possible here: When the
+     * currently active verify type is "none" but a client certificate is
+     * already known/present, it's enough to manually force a client
+     * verification but at least skip the I/O-intensive renegotation
+     * handshake.
+     */
+    if (dc->nVerifyClient != SSL_CVERIFY_UNSET) {
+        /* remember old state */
+        verify_old = SSL_get_verify_mode(ssl);
+        /* configure new state */
+        verify = SSL_VERIFY_NONE;
+
+        if (dc->nVerifyClient == SSL_CVERIFY_REQUIRE) {
+            verify |= SSL_VERIFY_PEER_STRICT;
+        }
+
+        if ((dc->nVerifyClient == SSL_CVERIFY_OPTIONAL) ||
+            (dc->nVerifyClient == SSL_CVERIFY_OPTIONAL_NO_CA))
+        {
+            verify |= SSL_VERIFY_PEER;
+        }
+
+        modssl_set_verify(ssl, verify, ssl_callback_SSLVerify);
+        SSL_set_verify_result(ssl, X509_V_OK);
+
+        /* determine whether we've to force a renegotiation */
+        if (!renegotiate && verify != verify_old) {
+            if (((verify_old == SSL_VERIFY_NONE) &&
+                 (verify     != SSL_VERIFY_NONE)) ||
+
+                (!(verify_old & SSL_VERIFY_PEER) &&
+                  (verify     & SSL_VERIFY_PEER)) ||
+
+                (!(verify_old & SSL_VERIFY_FAIL_IF_NO_PEER_CERT) &&
+                  (verify     & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)))
+            {
+                renegotiate = TRUE;
+                /* optimization */
+
+                if ((dc->nOptions & SSL_OPT_OPTRENEGOTIATE) &&
+                    (verify_old == SSL_VERIFY_NONE) &&
+                    ((peercert = SSL_get_peer_certificate(ssl)) != NULL))
+                {
+                    renegotiate_quick = TRUE;
+                    X509_free(peercert);
+                }
+
+                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0,
+                             r->server,
+                             "Changed client verification type will force "
+                             "%srenegotiation",
+                             renegotiate_quick ? "quick " : "");
+             }
+        }
+    }
+
+    /*
+     * override SSLCACertificateFile & SSLCACertificatePath
+     * This is only enabled if the SSL_set_cert_store() function
+     * is available in the ssl library.  the 1.x based mod_ssl
+     * used SSL_CTX_set_cert_store which is not thread safe.
+     */
+
+#ifdef HAVE_SSL_SET_CERT_STORE
+    /*
+     * check if per-dir and per-server config field are not the same.
+     * if f is defined in per-dir and not defined in per-server
+     * or f is defined in both but not the equal ...
+     */
+#define MODSSL_CFG_NE(f) \
+     (dc->f && (!sc->f || (sc->f && strNE(dc->f, sc->f))))
+
+#define MODSSL_CFG_CA(f) \
+     (dc->f ? dc->f : sc->f)
+
+    if (MODSSL_CFG_NE(szCACertificateFile) ||
+        MODSSL_CFG_NE(szCACertificatePath))
+    {
+        STACK_OF(X509_NAME) *ca_list;
+        const char *ca_file = MODSSL_CFG_CA(szCACertificateFile);
+        const char *ca_path = MODSSL_CFG_CA(szCACertificatePath);
+
+        cert_store = X509_STORE_new();
+
+        if (!X509_STORE_load_locations(cert_store, ca_file, ca_path)) {
+            ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                         "Unable to reconfigure verify locations "
+                         "for client authentication");
+            ssl_log_ssl_error(APLOG_MARK, APLOG_ERR, r->server);
+
+            X509_STORE_free(cert_store);
+
+            return HTTP_FORBIDDEN;
+        }
+
+        /* SSL_free will free cert_store */
+        SSL_set_cert_store(ssl, cert_store);
+
+        if (!(ca_list = ssl_init_FindCAList(r->server, r->pool,
+                                            ca_file, ca_path)))
+        {
+            ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                         "Unable to determine list of available "
+                         "CA certificates for client authentication");
+
+            return HTTP_FORBIDDEN;
+        }
+
+        SSL_set_client_CA_list(ssl, ca_list);
+        renegotiate = TRUE;
+
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
+                     "Changed client verification locations will force "
+                     "renegotiation");
+    }
+#endif /* HAVE_SSL_SET_CERT_STORE */
+
+    /* If a renegotiation is now required for this location, and the
+     * request includes a message body (and the client has not
+     * requested a "100 Continue" response), then the client will be
+     * streaming the request body over the wire already.  In that
+     * case, it is not possible to stop and perform a new SSL
+     * handshake immediately; once the SSL library moves to the
+     * "accept" state, it will reject the SSL packets which the client
+     * is sending for the request body.
+     * 
+     * To allow authentication to complete in this auth hook, the
+     * solution used here is to fill a (bounded) buffer with the
+     * request body, and then to reinject that request body later.
+     */
+    if (renegotiate && !renegotiate_quick
+        && (apr_table_get(r->headers_in, "transfer-encoding")
+            || (apr_table_get(r->headers_in, "content-length")
+                && strcmp(apr_table_get(r->headers_in, "content-length"), "0")))
+        && !r->expecting_100) {
+        int rv;
+
+        /* Fill the I/O buffer with the request body if possible. */
+        rv = ssl_io_buffer_fill(r);
+
+        if (rv) {
+            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
+                          "could not buffer message body to allow "
+                          "SSL renegotiation to proceed");
+            return rv;
+        }
+    }
+
+    /*
+     * now do the renegotiation if anything was actually reconfigured
+     */
+    if (renegotiate) {
+        /*
+         * Now we force the SSL renegotation by sending the Hello Request
+         * message to the client. Here we have to do a workaround: Actually
+         * OpenSSL returns immediately after sending the Hello Request (the
+         * intent AFAIK is because the SSL/TLS protocol says it's not a must
+         * that the client replies to a Hello Request). But because we insist
+         * on a reply (anything else is an error for us) we have to go to the
+         * ACCEPT state manually. Using SSL_set_accept_state() doesn't work
+         * here because it resets too much of the connection.  So we set the
+         * state explicitly and continue the handshake manually.
+         */
+        ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
+                     "Requesting connection re-negotiation");
+
+        if (renegotiate_quick) {
+            STACK_OF(X509) *cert_stack;
+
+            /* perform just a manual re-verification of the peer */
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, r->server,
+                         "Performing quick renegotiation: "
+                         "just re-verifying the peer");
+
+            cert_stack = (STACK_OF(X509) *)SSL_get_peer_cert_chain(ssl);
+
+            cert = SSL_get_peer_certificate(ssl);
+
+            if (!cert_stack && cert) {
+                /* client cert is in the session cache, but there is
+                 * no chain, since ssl3_get_client_certificate()
+                 * sk_X509_shift-ed the peer cert out of the chain.
+                 * we put it back here for the purpose of quick_renegotiation.
+                 */
+                cert_stack = sk_new_null();
+                sk_X509_push(cert_stack, MODSSL_PCHAR_CAST cert);
+            }
+
+            if (!cert_stack || (sk_X509_num(cert_stack) == 0)) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                             "Cannot find peer certificate chain");
+
+                return HTTP_FORBIDDEN;
+            }
+
+            if (!(cert_store ||
+                  (cert_store = SSL_CTX_get_cert_store(ctx))))
+            {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                             "Cannot find certificate storage");
+
+                return HTTP_FORBIDDEN;
+            }
+
+            if (!cert) {
+                cert = sk_X509_value(cert_stack, 0);
+            }
+
+            X509_STORE_CTX_init(&cert_store_ctx, cert_store, cert, cert_stack);
+            depth = SSL_get_verify_depth(ssl);
+
+            if (depth >= 0) {
+                X509_STORE_CTX_set_depth(&cert_store_ctx, depth);
+            }
+
+            X509_STORE_CTX_set_ex_data(&cert_store_ctx,
+                                       SSL_get_ex_data_X509_STORE_CTX_idx(),
+                                       (char *)ssl);
+
+            if (!modssl_X509_verify_cert(&cert_store_ctx)) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                             "Re-negotiation verification step failed");
+                ssl_log_ssl_error(APLOG_MARK, APLOG_ERR, r->server);
+            }
+
+            SSL_set_verify_result(ssl, cert_store_ctx.error);
+            X509_STORE_CTX_cleanup(&cert_store_ctx);
+
+            if (cert_stack != SSL_get_peer_cert_chain(ssl)) {
+                /* we created this ourselves, so free it */
+                sk_X509_pop_free(cert_stack, X509_free);
+            }
+        }
+        else {
+            request_rec *id = r->main ? r->main : r;
+
+            /* Additional mitigation for CVE-2009-3555: At this point,
+             * before renegotiating, an (entire) request has been read
+             * from the connection.  An attacker may have sent further
+             * data to "prefix" any subsequent request by the victim's
+             * client after the renegotiation; this data may already
+             * have been read and buffered.  Forcing a connection
+             * closure after the response ensures such data will be
+             * discarded.  Legimately pipelined HTTP requests will be
+             * retried anyway with this approach. */
+            if (has_buffered_data(r)) {
+                ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
+                              "insecure SSL re-negotiation required, but "
+                              "a pipelined request is present; keepalive "
+                              "disabled");
+                r->connection->keepalive = AP_CONN_CLOSE;
+            }
+
+            /* Perform a full renegotiation. */
+            ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r,
+                          "Performing full renegotiation: complete handshake "
+                          "protocol (%s support secure renegotiation)",
+#if defined(SSL_get_secure_renegotiation_support)
+                          SSL_get_secure_renegotiation_support(ssl) ? 
+                          "client does" : "client does not"
+#else
+                          "server does not"
+#endif
+                );
+
+            SSL_set_session_id_context(ssl,
+                                       (unsigned char *)&id,
+                                       sizeof(id));
+
+            /* Toggle the renegotiation state to allow the new
+             * handshake to proceed. */
+            sslconn->reneg_state = RENEG_ALLOW;
+            
+            SSL_renegotiate(ssl);
+            SSL_do_handshake(ssl);
+
+            if (SSL_get_state(ssl) != SSL_ST_OK) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                             "Re-negotiation request failed");
+                ssl_log_ssl_error(APLOG_MARK, APLOG_ERR, r->server);
+
+                r->connection->aborted = 1;
+                return HTTP_FORBIDDEN;
+            }
+
+            ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
+                         "Awaiting re-negotiation handshake");
+
+            SSL_set_state(ssl, SSL_ST_ACCEPT);
+            SSL_do_handshake(ssl);
+
+            sslconn->reneg_state = RENEG_REJECT;
+
+            if (SSL_get_state(ssl) != SSL_ST_OK) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                             "Re-negotiation handshake failed: "
+                        "Not accepted by client!?");
+
+                r->connection->aborted = 1;
+                return HTTP_FORBIDDEN;
+            }
+        }
+
+        /*
+         * Remember the peer certificate's DN
+         */
+        if ((cert = SSL_get_peer_certificate(ssl))) {
+            if (sslconn->client_cert) {
+                X509_free(sslconn->client_cert);
+            }
+            sslconn->client_cert = cert;
+            sslconn->client_dn = NULL;
+        }
+
+        /*
+         * Finally check for acceptable renegotiation results
+         */
+        if (dc->nVerifyClient != SSL_CVERIFY_NONE) {
+            BOOL do_verify = (dc->nVerifyClient == SSL_CVERIFY_REQUIRE);
+
+            if (do_verify && (SSL_get_verify_result(ssl) != X509_V_OK)) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                             "Re-negotiation handshake failed: "
+                             "Client verification failed");
+
+                return HTTP_FORBIDDEN;
+            }
+
+            if (do_verify) {
+                if ((peercert = SSL_get_peer_certificate(ssl)) == NULL) {
+                    ap_log_error(APLOG_MARK, APLOG_ERR, 0, r->server,
+                                 "Re-negotiation handshake failed: "
+                                 "Client certificate missing");
+
+                    return HTTP_FORBIDDEN;
+                }
+
+                X509_free(peercert);
+            }
+        }
+        
+        /*
+         * Also check that SSLCipherSuite has been enforced as expected.
+         */
+        if (cipher_list) {
+            cipher = SSL_get_current_cipher(ssl);
+            if (sk_SSL_CIPHER_find(cipher_list, cipher) < 0) {
+                ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
+                             "SSL cipher suite not renegotiated: "
+                             "access to %s denied using cipher %s",
+                              r->filename,
+                              SSL_CIPHER_get_name(cipher));
+                return HTTP_FORBIDDEN;
+            }
+        }
+    }
+
+    /* If we're trying to have the user name set from a client
+     * certificate then we need to set it here. This should be safe as
+     * the user name probably isn't important from an auth checking point
+     * of view as the certificate supplied acts in that capacity.
+     * However, if FakeAuth is being used then this isn't the case so
+     * we need to postpone setting the username until later.
+     */
+    if ((dc->nOptions & SSL_OPT_FAKEBASICAUTH) == 0 && dc->szUserName) {
+        char *val = ssl_var_lookup(r->pool, r->server, r->connection,
+                                   r, (char *)dc->szUserName);
+        if (val && val[0])
+            r->user = val;
+    } 
+
+    /*
+     * Check SSLRequire boolean expressions
+     */
+    requires = dc->aRequirement;
+    ssl_requires = (ssl_require_t *)requires->elts;
+
+    for (i = 0; i < requires->nelts; i++) {
+        ssl_require_t *req = &ssl_requires[i];
+        ok = ssl_expr_exec(r, req->mpExpr);
+
+        if (ok < 0) {
+            cp = apr_psprintf(r->pool,
+                              "Failed to execute "
+                              "SSL requirement expression: %s",
+                              ssl_expr_get_error());
+
+            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, 
+                          "access to %s failed, reason: %s",
+                          r->filename, cp);
+
+            /* remember forbidden access for strict require option */
+            apr_table_setn(r->notes, "ssl-access-forbidden", "1");
+
+            return HTTP_FORBIDDEN;
+        }
+
+        if (ok != 1) {
+            ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
+                         "Access to %s denied for %s "
+                         "(requirement expression not fulfilled)",
+                         r->filename, r->connection->remote_ip);
+
+            ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
+                         "Failed expression: %s", req->cpExpr);
+
+            ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r, 
+                          "access to %s failed, reason: %s",
+                          r->filename,
+                          "SSL requirement expression not fulfilled "
+                          "(see SSL logfile for more details)");
+
+            /* remember forbidden access for strict require option */
+            apr_table_setn(r->notes, "ssl-access-forbidden", "1");
+
+            return HTTP_FORBIDDEN;
+        }
+    }
+
+    /*
+     * Else access is granted from our point of view (except vendor
+     * handlers override). But we have to return DECLINED here instead
+     * of OK, because mod_auth and other modules still might want to
+     * deny access.
+     */
+
+    return DECLINED;
+}
+
+/*
+ *  Authentication Handler:
+ *  Fake a Basic authentication from the X509 client certificate.
+ *
+ *  This must be run fairly early on to prevent a real authentication from
+ *  occuring, in particular it must be run before anything else that
+ *  authenticates a user.  This means that the Module statement for this
+ *  module should be LAST in the Configuration file.
+ */
+int ssl_hook_UserCheck(request_rec *r)
+{
+    SSLConnRec *sslconn = myConnConfig(r->connection);
+    SSLSrvConfigRec *sc = mySrvConfig(r->server);
+    SSLDirConfigRec *dc = myDirConfig(r);
+    char *clientdn;
+    const char *auth_line, *username, *password;
+
+    /*
+     * Additionally forbid access (again)
+     * when strict require option is used.
+     */
+    if ((dc->nOptions & SSL_OPT_STRICTREQUIRE) &&
+        (apr_table_get(r->notes, "ssl-access-forbidden")))
+    {
+        return HTTP_FORBIDDEN;
+    }
+
+    /*
+     * We decline when we are in a subrequest.  The Authorization header
+     * would already be present if it was added in the main request.
+     */
+    if (!ap_is_initial_req(r)) {
+        return DECLINED;
+    }
+
+    /*
+     * Make sure the user is not able to fake the client certificate
+     * based authentication by just entering an X.509 Subject DN
+     * ("/XX=YYY/XX=YYY/..") as the username and "password" as the
+     * password.
+     */
+    if ((auth_line = apr_table_get(r->headers_in, "Authorization"))) {
+        if (strcEQ(ap_getword(r->pool, &auth_line, ' '), "Basic")) {
+            while ((*auth_line == ' ') || (*auth_line == '\t')) {
+                auth_line++;
+            }
+
+            auth_line = ap_pbase64decode(r->pool, auth_line);
+            username = ap_getword_nulls(r->pool, &auth_line, ':');
+            password = auth_line;
+
+            if ((username[0] == '/') && strEQ(password, "password")) {
+                ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, r,
+                    "Encountered FakeBasicAuth spoof: %s", username);
+                return HTTP_FORBIDDEN;
+            }
+        }
+    }
+
+    /*
+     * We decline operation in various situations...
+     * - SSLOptions +FakeBasicAuth not configured
+     * - r->user already authenticated
+     * - ssl not enabled
+     * - client did not present a certificate
+     */
+    if (!(sc->enabled && sslconn && sslconn->ssl && sslconn->client_cert) ||
+        !(dc->nOptions & SSL_OPT_FAKEBASICAUTH) || r->user)
+    {
+        return DECLINED;
+    }
+    
+    if (!sslconn->client_dn) {
+        X509_NAME *name = X509_get_subject_name(sslconn->client_cert);
+        char *cp = X509_NAME_oneline(name, NULL, 0);
+        sslconn->client_dn = apr_pstrdup(r->connection->pool, cp);
+        modssl_free(cp);
+    }
+
+    clientdn = (char *)sslconn->client_dn;
+
+    /*
+     * Fake a password - which one would be immaterial, as, it seems, an empty
+     * password in the users file would match ALL incoming passwords, if only
+     * we were using the standard crypt library routine. Unfortunately, OpenSSL
+     * "fixes" a "bug" in crypt and thus prevents blank passwords from
+     * working.  (IMHO what they really fix is a bug in the users of the code
+     * - failing to program correctly for shadow passwords).  We need,
+     * therefore, to provide a password. This password can be matched by
+     * adding the string "xxj31ZMTZzkVA" as the password in the user file.
+     * This is just the crypted variant of the word "password" ;-)
+     */
+    auth_line = apr_pstrcat(r->pool, "Basic ", 
+                            ap_pbase64encode(r->pool, 
+                                             apr_pstrcat(r->pool, clientdn, 
+                                                         ":password", NULL)),
+                            NULL);
+    apr_table_set(r->headers_in, "Authorization", auth_line);
+
+    ap_log_error(APLOG_MARK, APLOG_INFO, 0, r->server,
+                 "Faking HTTP Basic Auth header: \"Authorization: %s\"",
+                 auth_line);
+
+    return DECLINED;
+}
+
+/* authorization phase */
+int ssl_hook_Auth(request_rec *r)
+{
+    SSLDirConfigRec *dc = myDirConfig(r);
+
+    /*
+     * Additionally forbid access (again)
+     * when strict require option is used.
+     */
+    if ((dc->nOptions & SSL_OPT_STRICTREQUIRE) &&
+        (apr_table_get(r->notes, "ssl-access-forbidden")))
+    {
+        return HTTP_FORBIDDEN;
+    }
+
+    return DECLINED;
+}
+
+/*
+ *   Fixup Handler
+ */
+
+static const char *ssl_hook_Fixup_vars[] = {
+    "SSL_VERSION_INTERFACE",
+    "SSL_VERSION_LIBRARY",
+    "SSL_PROTOCOL",
+    "SSL_SECURE_RENEG",
+    "SSL_CIPHER",
+    "SSL_CIPHER_EXPORT",
+    "SSL_CIPHER_USEKEYSIZE",
+    "SSL_CIPHER_ALGKEYSIZE",
+    "SSL_CLIENT_VERIFY",
+    "SSL_CLIENT_M_VERSION",
+    "SSL_CLIENT_M_SERIAL",
+    "SSL_CLIENT_V_START",
+    "SSL_CLIENT_V_END",
+    "SSL_CLIENT_S_DN",
+    "SSL_CLIENT_S_DN_C",
+    "SSL_CLIENT_S_DN_ST",
+    "SSL_CLIENT_S_DN_L",
+    "SSL_CLIENT_S_DN_O",
+    "SSL_CLIENT_S_DN_OU",
+    "SSL_CLIENT_S_DN_CN",
+    "SSL_CLIENT_S_DN_T",
+    "SSL_CLIENT_S_DN_I",
+    "SSL_CLIENT_S_DN_G",
+    "SSL_CLIENT_S_DN_S",
+    "SSL_CLIENT_S_DN_D",
+    "SSL_CLIENT_S_DN_UID",
+    "SSL_CLIENT_S_DN_Email",
+    "SSL_CLIENT_I_DN",
+    "SSL_CLIENT_I_DN_C",
+    "SSL_CLIENT_I_DN_ST",
+    "SSL_CLIENT_I_DN_L",
+    "SSL_CLIENT_I_DN_O",
+    "SSL_CLIENT_I_DN_OU",
+    "SSL_CLIENT_I_DN_CN",
+    "SSL_CLIENT_I_DN_T",
+    "SSL_CLIENT_I_DN_I",
+    "SSL_CLIENT_I_DN_G",
+    "SSL_CLIENT_I_DN_S",
+    "SSL_CLIENT_I_DN_D",
+    "SSL_CLIENT_I_DN_UID",
+    "SSL_CLIENT_I_DN_Email",
+    "SSL_CLIENT_A_KEY",
+    "SSL_CLIENT_A_SIG",
+    "SSL_SERVER_M_VERSION",
+    "SSL_SERVER_M_SERIAL",
+    "SSL_SERVER_V_START",
+    "SSL_SERVER_V_END",
+    "SSL_SERVER_S_DN",
+    "SSL_SERVER_S_DN_C",
+    "SSL_SERVER_S_DN_ST",
+    "SSL_SERVER_S_DN_L",
+    "SSL_SERVER_S_DN_O",
+    "SSL_SERVER_S_DN_OU",
+    "SSL_SERVER_S_DN_CN",
+    "SSL_SERVER_S_DN_T",
+    "SSL_SERVER_S_DN_I",
+    "SSL_SERVER_S_DN_G",
+    "SSL_SERVER_S_DN_S",
+    "SSL_SERVER_S_DN_D",
+    "SSL_SERVER_S_DN_UID",
+    "SSL_SERVER_S_DN_Email",
+    "SSL_SERVER_I_DN",
+    "SSL_SERVER_I_DN_C",
+    "SSL_SERVER_I_DN_ST",
+    "SSL_SERVER_I_DN_L",
+    "SSL_SERVER_I_DN_O",
+    "SSL_SERVER_I_DN_OU",
+    "SSL_SERVER_I_DN_CN",
+    "SSL_SERVER_I_DN_T",
+    "SSL_SERVER_I_DN_I",
+    "SSL_SERVER_I_DN_G",
+    "SSL_SERVER_I_DN_S",
+    "SSL_SERVER_I_DN_D",
+    "SSL_SERVER_I_DN_UID",
+    "SSL_SERVER_I_DN_Email",
+    "SSL_SERVER_A_KEY",
+    "SSL_SERVER_A_SIG",
+    "SSL_SESSION_ID",
+    NULL
+};
+
+int ssl_hook_Fixup(request_rec *r)
+{
+    SSLConnRec *sslconn = myConnConfig(r->connection);
+    SSLSrvConfigRec *sc = mySrvConfig(r->server);
+    SSLDirConfigRec *dc = myDirConfig(r);
+    apr_table_t *env = r->subprocess_env;
+    char *var, *val = "";
+    STACK_OF(X509) *peer_certs;
+    SSL *ssl;
+    int i;
+
+    /*
+     * Check to see if SSL is on
+     */
+    if (!(sc->enabled && sslconn && (ssl = sslconn->ssl))) {
+        return DECLINED;
+    }
+
+    /*
+     * Annotate the SSI/CGI environment with standard SSL information
+     */
+    /* the always present HTTPS (=HTTP over SSL) flag! */
+    apr_table_setn(env, "HTTPS", "on"); 
+
+    /* standard SSL environment variables */
+    if (dc->nOptions & SSL_OPT_STDENVVARS) {
+        for (i = 0; ssl_hook_Fixup_vars[i]; i++) {
+            var = (char *)ssl_hook_Fixup_vars[i];
+            val = ssl_var_lookup(r->pool, r->server, r->connection, r, var);
+            if (!strIsEmpty(val)) {
+                apr_table_setn(env, var, val);
+            }
+        }
+    }
+
+    /*
+     * On-demand bloat up the SSI/CGI environment with certificate data
+     */
+    if (dc->nOptions & SSL_OPT_EXPORTCERTDATA) {
+        val = ssl_var_lookup(r->pool, r->server, r->connection,
+                             r, "SSL_SERVER_CERT");
+
+        apr_table_setn(env, "SSL_SERVER_CERT", val);
+
+        val = ssl_var_lookup(r->pool, r->server, r->connection,
+                             r, "SSL_CLIENT_CERT");
+
+        apr_table_setn(env, "SSL_CLIENT_CERT", val);
+
+        if ((peer_certs = (STACK_OF(X509) *)SSL_get_peer_cert_chain(ssl))) {
+            for (i = 0; i < sk_X509_num(peer_certs); i++) {
+                var = apr_psprintf(r->pool, "SSL_CLIENT_CERT_CHAIN_%d", i);
+                val = ssl_var_lookup(r->pool, r->server, r->connection,
+                                     r, var);
+                if (val) {
+                    apr_table_setn(env, var, val);
+                }
+            }
+        }
+    }
+
+
+#ifdef SSL_get_secure_renegotiation_support
+    apr_table_setn(r->notes, "ssl-secure-reneg", 
+                   SSL_get_secure_renegotiation_support(ssl) ? "1" : "0");
+#endif
+
+    return DECLINED;
+}
+
+/*  _________________________________________________________________
+**
+**  OpenSSL Callback Functions
+**  _________________________________________________________________
+*/
+
+/*
+ * Handle out temporary RSA private keys on demand
+ *
+ * The background of this as the TLSv1 standard explains it:
+ *
+ * | D.1. Temporary RSA keys
+ * |
+ * |    US Export restrictions limit RSA keys used for encryption to 512
+ * |    bits, but do not place any limit on lengths of RSA keys used for
+ * |    signing operations. Certificates often need to be larger than 512
+ * |    bits, since 512-bit RSA keys are not secure enough for high-value
+ * |    transactions or for applications requiring long-term security. Some
+ * |    certificates are also designated signing-only, in which case they
+ * |    cannot be used for key exchange.
+ * |
+ * |    When the public key in the certificate cannot be used for encryption,
+ * |    the server signs a temporary RSA key, which is then exchanged. In
+ * |    exportable applications, the temporary RSA key should be the maximum
+ * |    allowable length (i.e., 512 bits). Because 512-bit RSA keys are
+ * |    relatively insecure, they should be changed often. For typical
+ * |    electronic commerce applications, it is suggested that keys be
+ * |    changed daily or every 500 transactions, and more often if possible.
+ * |    Note that while it is acceptable to use the same temporary key for
+ * |    multiple transactions, it must be signed each time it is used.
+ * |
+ * |    RSA key generation is a time-consuming process. In many cases, a
+ * |    low-priority process can be assigned the task of key generation.
+ * |    Whenever a new key is completed, the existing temporary key can be
+ * |    replaced with the new one.
+ *
+ * XXX: base on comment above, if thread support is enabled,
+ * we should spawn a low-priority thread to generate new keys
+ * on the fly.
+ *
+ * So we generated 512 and 1024 bit temporary keys on startup
+ * which we now just hand out on demand....
+ */
+
+RSA *ssl_callback_TmpRSA(SSL *ssl, int export, int keylen)
+{
+    conn_rec *c = (conn_rec *)SSL_get_app_data(ssl);
+    SSLModConfigRec *mc = myModConfig(c->base_server);
+    int idx;
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, c->base_server,
+                 "handing out temporary %d bit RSA key", keylen);
+
+    /* doesn't matter if export flag is on,
+     * we won't be asked for keylen > 512 in that case.
+     * if we are asked for a keylen > 1024, it is too expensive
+     * to generate on the fly.
+     * XXX: any reason not to generate 2048 bit keys at startup?
+     */
+
+    switch (keylen) {
+      case 512:
+        idx = SSL_TMP_KEY_RSA_512;
+        break;
+
+      case 1024:
+      default:
+        idx = SSL_TMP_KEY_RSA_1024;
+    }
+
+    return (RSA *)mc->pTmpKeys[idx];
+}
+
+/* 
+ * Hand out the already generated DH parameters...
+ */
+DH *ssl_callback_TmpDH(SSL *ssl, int export, int keylen)
+{
+    conn_rec *c = (conn_rec *)SSL_get_app_data(ssl);
+    SSLModConfigRec *mc = myModConfig(c->base_server);
+    int idx;
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, c->base_server,
+                 "handing out temporary %d bit DH key", keylen);
+
+    switch (keylen) {
+      case 512:
+        idx = SSL_TMP_KEY_DH_512;
+        break;
+
+      case 1024:
+      default:
+        idx = SSL_TMP_KEY_DH_1024;
+    }
+
+    return (DH *)mc->pTmpKeys[idx];
+}
+
+/*
+ * This OpenSSL callback function is called when OpenSSL
+ * does client authentication and verifies the certificate chain.
+ */
+int ssl_callback_SSLVerify(int ok, X509_STORE_CTX *ctx)
+{
+    /* Get Apache context back through OpenSSL context */
+    SSL *ssl = X509_STORE_CTX_get_ex_data(ctx,
+                                          SSL_get_ex_data_X509_STORE_CTX_idx());
+    conn_rec *conn      = (conn_rec *)SSL_get_app_data(ssl);
+    server_rec *s       = conn->base_server;
+    request_rec *r      = (request_rec *)SSL_get_app_data2(ssl);
+
+    SSLSrvConfigRec *sc = mySrvConfig(s);
+    SSLDirConfigRec *dc = r ? myDirConfig(r) : NULL;
+    SSLConnRec *sslconn = myConnConfig(conn);
+    modssl_ctx_t *mctx  = myCtxConfig(sslconn, sc);
+
+    /* Get verify ingredients */
+    int errnum   = X509_STORE_CTX_get_error(ctx);
+    int errdepth = X509_STORE_CTX_get_error_depth(ctx);
+    int depth, verify;
+
+    /*
+     * Log verification information
+     */
+    if (s->loglevel >= APLOG_DEBUG) {
+        X509 *cert  = X509_STORE_CTX_get_current_cert(ctx);
+        char *sname = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0);
+        char *iname = X509_NAME_oneline(X509_get_issuer_name(cert),  NULL, 0);
+
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                     "Certificate Verification: "
+                     "depth: %d, subject: %s, issuer: %s",
+                     errdepth,
+                     sname ? sname : "-unknown-",
+                     iname ? iname : "-unknown-");
+
+        if (sname) {
+            modssl_free(sname);
+        }
+
+        if (iname) {
+            modssl_free(iname);
+        }
+    }
+
+    /*
+     * Check for optionally acceptable non-verifiable issuer situation
+     */
+    if (dc && (dc->nVerifyClient != SSL_CVERIFY_UNSET)) {
+        verify = dc->nVerifyClient;
+    }
+    else {
+        verify = mctx->auth.verify_mode;
+    }
+
+    if (verify == SSL_CVERIFY_NONE) {
+        /* 
+         * SSLProxyVerify is either not configured or set to "none".
+         * (this callback doesn't happen in the server context if SSLVerify
+         *  is not configured or set to "none")
+         */
+        return TRUE;
+    }
+
+    if (ssl_verify_error_is_optional(errnum) &&
+        (verify == SSL_CVERIFY_OPTIONAL_NO_CA))
+    {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                     "Certificate Verification: Verifiable Issuer is "
+                     "configured as optional, therefore we're accepting "
+                     "the certificate");
+
+        sslconn->verify_info = "GENEROUS";
+        ok = TRUE;
+    }
+
+    /*
+     * Additionally perform CRL-based revocation checks
+     */
+    if (ok) {
+        if (!(ok = ssl_callback_SSLVerify_CRL(ok, ctx, conn))) {
+            errnum = X509_STORE_CTX_get_error(ctx);
+        }
+    }
+
+    /*
+     * If we already know it's not ok, log the real reason
+     */
+    if (!ok) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s,
+                     "Certificate Verification: Error (%d): %s",
+                     errnum, X509_verify_cert_error_string(errnum));
+
+        if (sslconn->client_cert) {
+            X509_free(sslconn->client_cert);
+            sslconn->client_cert = NULL;
+        }
+        sslconn->client_dn = NULL;
+        sslconn->verify_error = X509_verify_cert_error_string(errnum);
+    }
+
+    /*
+     * Finally check the depth of the certificate verification
+     */
+    if (dc && (dc->nVerifyDepth != UNSET)) {
+        depth = dc->nVerifyDepth;
+    }
+    else {
+        depth = mctx->auth.verify_depth;
+    }
+
+    if (errdepth > depth) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s,
+                     "Certificate Verification: Certificate Chain too long "
+                     "(chain has %d certificates, but maximum allowed are "
+                     "only %d)",
+                     errdepth, depth);
+
+        errnum = X509_V_ERR_CERT_CHAIN_TOO_LONG;
+        sslconn->verify_error = X509_verify_cert_error_string(errnum);
+
+        ok = FALSE;
+    }
+
+    /*
+     * And finally signal OpenSSL the (perhaps changed) state
+     */
+    return ok;
+}
+
+int ssl_callback_SSLVerify_CRL(int ok, X509_STORE_CTX *ctx, conn_rec *c)
+{
+    server_rec *s       = c->base_server;
+    SSLSrvConfigRec *sc = mySrvConfig(s);
+    SSLConnRec *sslconn = myConnConfig(c);
+    modssl_ctx_t *mctx  = myCtxConfig(sslconn, sc);
+    X509_OBJECT obj;
+    X509_NAME *subject, *issuer;
+    X509 *cert;
+    X509_CRL *crl;
+    EVP_PKEY *pubkey;
+    int i, n, rc;
+
+    /*
+     * Unless a revocation store for CRLs was created we
+     * cannot do any CRL-based verification, of course.
+     */
+    if (!mctx->crl) {
+        return ok;
+    }
+
+    /*
+     * Determine certificate ingredients in advance
+     */
+    cert    = X509_STORE_CTX_get_current_cert(ctx);
+    subject = X509_get_subject_name(cert);
+    issuer  = X509_get_issuer_name(cert);
+
+    /*
+     * OpenSSL provides the general mechanism to deal with CRLs but does not
+     * use them automatically when verifying certificates, so we do it
+     * explicitly here. We will check the CRL for the currently checked
+     * certificate, if there is such a CRL in the store.
+     *
+     * We come through this procedure for each certificate in the certificate
+     * chain, starting with the root-CA's certificate. At each step we've to
+     * both verify the signature on the CRL (to make sure it's a valid CRL)
+     * and it's revocation list (to make sure the current certificate isn't
+     * revoked).  But because to check the signature on the CRL we need the
+     * public key of the issuing CA certificate (which was already processed
+     * one round before), we've a little problem. But we can both solve it and
+     * at the same time optimize the processing by using the following
+     * verification scheme (idea and code snippets borrowed from the GLOBUS
+     * project):
+     *
+     * 1. We'll check the signature of a CRL in each step when we find a CRL
+     *    through the _subject_ name of the current certificate. This CRL
+     *    itself will be needed the first time in the next round, of course.
+     *    But we do the signature processing one round before this where the
+     *    public key of the CA is available.
+     *
+     * 2. We'll check the revocation list of a CRL in each step when
+     *    we find a CRL through the _issuer_ name of the current certificate.
+     *    This CRLs signature was then already verified one round before.
+     *
+     * This verification scheme allows a CA to revoke its own certificate as
+     * well, of course.
+     */
+
+    /*
+     * Try to retrieve a CRL corresponding to the _subject_ of
+     * the current certificate in order to verify it's integrity.
+     */
+    memset((char *)&obj, 0, sizeof(obj));
+    rc = SSL_X509_STORE_lookup(mctx->crl,
+                               X509_LU_CRL, subject, &obj);
+    crl = obj.data.crl;
+
+    if ((rc > 0) && crl) {
+        /*
+         * Log information about CRL
+         * (A little bit complicated because of ASN.1 and BIOs...)
+         */
+        if (s->loglevel >= APLOG_DEBUG) {
+            char buff[512]; /* should be plenty */
+            BIO *bio = BIO_new(BIO_s_mem());
+
+            BIO_printf(bio, "CA CRL: Issuer: ");
+            X509_NAME_print(bio, issuer, 0);
+
+            BIO_printf(bio, ", lastUpdate: ");
+            ASN1_UTCTIME_print(bio, X509_CRL_get_lastUpdate(crl));
+
+            BIO_printf(bio, ", nextUpdate: ");
+            ASN1_UTCTIME_print(bio, X509_CRL_get_nextUpdate(crl));
+
+            n = BIO_read(bio, buff, sizeof(buff) - 1);
+            buff[n] = '\0';
+
+            BIO_free(bio);
+
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, buff);
+        }
+
+        /*
+         * Verify the signature on this CRL
+         */
+        pubkey = X509_get_pubkey(cert);
+        rc = X509_CRL_verify(crl, pubkey);
+#ifdef OPENSSL_VERSION_NUMBER
+        /* Only refcounted in OpenSSL */
+        if (pubkey)
+            EVP_PKEY_free(pubkey);
+#endif
+        if (rc <= 0) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
+                         "Invalid signature on CRL");
+
+            X509_STORE_CTX_set_error(ctx, X509_V_ERR_CRL_SIGNATURE_FAILURE);
+            X509_OBJECT_free_contents(&obj);
+            return FALSE;
+        }
+
+        /*
+         * Check date of CRL to make sure it's not expired
+         */
+        i = X509_cmp_current_time(X509_CRL_get_nextUpdate(crl));
+
+        if (i == 0) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
+                         "Found CRL has invalid nextUpdate field");
+
+            X509_STORE_CTX_set_error(ctx,
+                                     X509_V_ERR_ERROR_IN_CRL_NEXT_UPDATE_FIELD);
+            X509_OBJECT_free_contents(&obj);
+
+            return FALSE;
+        }
+
+        if (i < 0) {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
+                         "Found CRL is expired - "
+                         "revoking all certificates until you get updated CRL");
+
+            X509_STORE_CTX_set_error(ctx, X509_V_ERR_CRL_HAS_EXPIRED);
+            X509_OBJECT_free_contents(&obj);
+
+            return FALSE;
+        }
+
+        X509_OBJECT_free_contents(&obj);
+    }
+
+    /*
+     * Try to retrieve a CRL corresponding to the _issuer_ of
+     * the current certificate in order to check for revocation.
+     */
+    memset((char *)&obj, 0, sizeof(obj));
+    rc = SSL_X509_STORE_lookup(mctx->crl,
+                               X509_LU_CRL, issuer, &obj);
+
+    crl = obj.data.crl;
+    if ((rc > 0) && crl) {
+        /*
+         * Check if the current certificate is revoked by this CRL
+         */
+        n = sk_X509_REVOKED_num(X509_CRL_get_REVOKED(crl));
+
+        for (i = 0; i < n; i++) {
+            X509_REVOKED *revoked =
+                sk_X509_REVOKED_value(X509_CRL_get_REVOKED(crl), i);
+
+            ASN1_INTEGER *sn = X509_REVOKED_get_serialNumber(revoked);
+
+            if (!ASN1_INTEGER_cmp(sn, X509_get_serialNumber(cert))) {
+                if (s->loglevel >= APLOG_DEBUG) {
+                    char *cp = X509_NAME_oneline(issuer, NULL, 0);
+                    long serial = ASN1_INTEGER_get(sn);
+
+                    ap_log_error(APLOG_MARK, APLOG_INFO, 0, s,
+                                 "Certificate with serial %ld (0x%lX) "
+                                 "revoked per CRL from issuer %s",
+                                 serial, serial, cp);
+                    modssl_free(cp);
+                }
+
+                X509_STORE_CTX_set_error(ctx, X509_V_ERR_CERT_REVOKED);
+                X509_OBJECT_free_contents(&obj);
+
+                return FALSE;
+            }
+        }
+
+        X509_OBJECT_free_contents(&obj);
+    }
+
+    return ok;
+}
+
+#define SSLPROXY_CERT_CB_LOG_FMT \
+   "Proxy client certificate callback: (%s) "
+
+static void modssl_proxy_info_log(server_rec *s,
+                                  X509_INFO *info,
+                                  const char *msg)
+{
+    SSLSrvConfigRec *sc = mySrvConfig(s);
+    char name_buf[256];
+    X509_NAME *name;
+    char *dn;
+
+    if (s->loglevel < APLOG_DEBUG) {
+        return;
+    }
+
+    name = X509_get_subject_name(info->x509);
+    dn = X509_NAME_oneline(name, name_buf, sizeof(name_buf));
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                 SSLPROXY_CERT_CB_LOG_FMT "%s, sending %s", 
+                 sc->vhost_id, msg, dn ? dn : "-uknown-");
+}
+
+/*
+ * caller will decrement the cert and key reference
+ * so we need to increment here to prevent them from
+ * being freed.
+ */
+#define modssl_set_cert_info(info, cert, pkey) \
+    *cert = info->x509; \
+    X509_reference_inc(*cert); \
+    *pkey = info->x_pkey->dec_pkey; \
+    EVP_PKEY_reference_inc(*pkey)
+
+int ssl_callback_proxy_cert(SSL *ssl, MODSSL_CLIENT_CERT_CB_ARG_TYPE **x509, EVP_PKEY **pkey) 
+{
+    conn_rec *c = (conn_rec *)SSL_get_app_data(ssl);
+    server_rec *s = c->base_server;
+    SSLSrvConfigRec *sc = mySrvConfig(s);
+    X509_NAME *ca_name, *issuer;
+    X509_INFO *info;
+    STACK_OF(X509_NAME) *ca_list;
+    STACK_OF(X509_INFO) *certs = sc->proxy->pkp->certs;
+    int i, j;
+    
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, 
+                 SSLPROXY_CERT_CB_LOG_FMT "entered",
+                 sc->vhost_id);
+
+    if (!certs || (sk_X509_INFO_num(certs) <= 0)) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, s,
+                     SSLPROXY_CERT_CB_LOG_FMT
+                     "downstream server wanted client certificate "
+                     "but none are configured", sc->vhost_id);
+        return FALSE;
+    }                                                                     
+
+    ca_list = SSL_get_client_CA_list(ssl);
+
+    if (!ca_list || (sk_X509_NAME_num(ca_list) <= 0)) {
+        /* 
+         * downstream server didn't send us a list of acceptable CA certs, 
+         * so we send the first client cert in the list.
+         */   
+        info = sk_X509_INFO_value(certs, 0);
+        
+        modssl_proxy_info_log(s, info, "no acceptable CA list");
+
+        modssl_set_cert_info(info, x509, pkey);
+
+        return TRUE;
+    }         
+
+    for (i = 0; i < sk_X509_NAME_num(ca_list); i++) {
+        ca_name = sk_X509_NAME_value(ca_list, i);
+
+        for (j = 0; j < sk_X509_INFO_num(certs); j++) {
+            info = sk_X509_INFO_value(certs, j);
+            issuer = X509_get_issuer_name(info->x509);
+
+            if (X509_NAME_cmp(issuer, ca_name) == 0) {
+                modssl_proxy_info_log(s, info, "found acceptable cert");
+
+                modssl_set_cert_info(info, x509, pkey);
+
+                return TRUE;
+            }
+        }
+    }
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                 SSLPROXY_CERT_CB_LOG_FMT
+                 "no client certificate found!?", sc->vhost_id);
+
+    return FALSE; 
+}
+
+static void ssl_session_log(server_rec *s,
+                            const char *request,
+                            unsigned char *id,
+                            unsigned int idlen,
+                            const char *status,
+                            const char *result,
+                            long timeout)
+{
+    char buf[SSL_SESSION_ID_STRING_LEN];
+    char timeout_str[56] = {'\0'};
+
+    if (s->loglevel < APLOG_DEBUG) {
+        return;
+    }
+
+    if (timeout) {
+        apr_snprintf(timeout_str, sizeof(timeout_str),
+                     "timeout=%lds ", (timeout - time(NULL)));
+    }
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                 "Inter-Process Session Cache: "
+                 "request=%s status=%s id=%s %s(session %s)",
+                 request, status,
+                 SSL_SESSION_id2sz(id, idlen, buf, sizeof(buf)),
+                 timeout_str, result);
+}
+
+/*
+ *  This callback function is executed by OpenSSL whenever a new SSL_SESSION is
+ *  added to the internal OpenSSL session cache. We use this hook to spread the
+ *  SSL_SESSION also to the inter-process disk-cache to make share it with our
+ *  other Apache pre-forked server processes.
+ */
+int ssl_callback_NewSessionCacheEntry(SSL *ssl, SSL_SESSION *session)
+{
+    /* Get Apache context back through OpenSSL context */
+    conn_rec *conn      = (conn_rec *)SSL_get_app_data(ssl);
+    server_rec *s       = conn->base_server;
+    SSLSrvConfigRec *sc = mySrvConfig(s);
+    long timeout        = sc->session_cache_timeout;
+    BOOL rc;
+    unsigned char *id;
+    unsigned int idlen;
+
+    /*
+     * Set the timeout also for the internal OpenSSL cache, because this way
+     * our inter-process cache is consulted only when it's really necessary.
+     */
+    SSL_set_timeout(session, timeout);
+
+    /*
+     * Store the SSL_SESSION in the inter-process cache with the
+     * same expire time, so it expires automatically there, too.
+     */
+    id = SSL_SESSION_get_session_id(session);
+    idlen = SSL_SESSION_get_session_id_length(session);
+
+    timeout += modssl_session_get_time(session);
+
+    rc = ssl_scache_store(s, id, idlen, timeout, session);
+
+    ssl_session_log(s, "SET", id, idlen,
+                    rc == TRUE ? "OK" : "BAD",
+                    "caching", timeout);
+
+    /*
+     * return 0 which means to OpenSSL that the session is still
+     * valid and was not freed by us with SSL_SESSION_free().
+     */
+    return 0;
+}
+
+/*
+ *  This callback function is executed by OpenSSL whenever a
+ *  SSL_SESSION is looked up in the internal OpenSSL cache and it
+ *  was not found. We use this to lookup the SSL_SESSION in the
+ *  inter-process disk-cache where it was perhaps stored by one
+ *  of our other Apache pre-forked server processes.
+ */
+SSL_SESSION *ssl_callback_GetSessionCacheEntry(SSL *ssl,
+                                               unsigned char *id,
+                                               int idlen, int *do_copy)
+{
+    /* Get Apache context back through OpenSSL context */
+    conn_rec *conn = (conn_rec *)SSL_get_app_data(ssl);
+    server_rec *s  = conn->base_server;
+    SSL_SESSION *session;
+
+    /*
+     * Try to retrieve the SSL_SESSION from the inter-process cache
+     */
+    session = ssl_scache_retrieve(s, id, idlen);
+
+    ssl_session_log(s, "GET", id, idlen,
+                    session ? "FOUND" : "MISSED",
+                    session ? "reuse" : "renewal", 0);
+
+    /*
+     * Return NULL or the retrieved SSL_SESSION. But indicate (by
+     * setting do_copy to 0) that the reference count on the
+     * SSL_SESSION should not be incremented by the SSL library,
+     * because we will no longer hold a reference to it ourself.
+     */
+    *do_copy = 0;
+
+    return session;
+}
+
+/*
+ *  This callback function is executed by OpenSSL whenever a
+ *  SSL_SESSION is removed from the the internal OpenSSL cache.
+ *  We use this to remove the SSL_SESSION in the inter-process
+ *  disk-cache, too.
+ */
+void ssl_callback_DelSessionCacheEntry(SSL_CTX *ctx,
+                                       SSL_SESSION *session)
+{
+    server_rec *s;
+    SSLSrvConfigRec *sc;
+    unsigned char *id;
+    unsigned int idlen;
+
+    /*
+     * Get Apache context back through OpenSSL context
+     */
+    if (!(s = (server_rec *)SSL_CTX_get_app_data(ctx))) {
+        return; /* on server shutdown Apache is already gone */
+    }
+
+    sc = mySrvConfig(s);
+
+    /*
+     * Remove the SSL_SESSION from the inter-process cache
+     */
+    id = SSL_SESSION_get_session_id(session);
+    idlen = SSL_SESSION_get_session_id_length(session);
+
+    ssl_scache_remove(s, id, idlen);
+
+    ssl_session_log(s, "REM", id, idlen,
+                    "OK", "dead", 0);
+
+    return;
+}
+
+/* Dump debugginfo trace to the log file. */
+static void log_tracing_state(MODSSL_INFO_CB_ARG_TYPE ssl, conn_rec *c,
+                              server_rec *s, int where, int rc)
+{
+    /*
+     * create the various trace messages
+     */
+    if (where & SSL_CB_HANDSHAKE_START) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                     "%s: Handshake: start", SSL_LIBRARY_NAME);
+    }
+    else if (where & SSL_CB_HANDSHAKE_DONE) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                     "%s: Handshake: done", SSL_LIBRARY_NAME);
+    }
+    else if (where & SSL_CB_LOOP) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                     "%s: Loop: %s",
+                     SSL_LIBRARY_NAME, SSL_state_string_long(ssl));
+    }
+    else if (where & SSL_CB_READ) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                     "%s: Read: %s",
+                     SSL_LIBRARY_NAME, SSL_state_string_long(ssl));
+    }
+    else if (where & SSL_CB_WRITE) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                     "%s: Write: %s",
+                     SSL_LIBRARY_NAME, SSL_state_string_long(ssl));
+    }
+    else if (where & SSL_CB_ALERT) {
+        char *str = (where & SSL_CB_READ) ? "read" : "write";
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                     "%s: Alert: %s:%s:%s",
+                     SSL_LIBRARY_NAME, str,
+                     SSL_alert_type_string_long(rc),
+                     SSL_alert_desc_string_long(rc));
+    }
+    else if (where & SSL_CB_EXIT) {
+        if (rc == 0) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                         "%s: Exit: failed in %s",
+                         SSL_LIBRARY_NAME, SSL_state_string_long(ssl));
+        }
+        else if (rc < 0) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s,
+                         "%s: Exit: error in %s",
+                         SSL_LIBRARY_NAME, SSL_state_string_long(ssl));
+        }
+    }
+
+    /*
+     * Because SSL renegotations can happen at any time (not only after
+     * SSL_accept()), the best way to log the current connection details is
+     * right after a finished handshake.
+     */
+    if (where & SSL_CB_HANDSHAKE_DONE) {
+        ap_log_error(APLOG_MARK, APLOG_INFO, 0, s,
+                     "Connection: Client IP: %s, Protocol: %s, "
+                     "Cipher: %s (%s/%s bits)",
+                     ssl_var_lookup(NULL, s, c, NULL, "REMOTE_ADDR"),
+                     ssl_var_lookup(NULL, s, c, NULL, "SSL_PROTOCOL"),
+                     ssl_var_lookup(NULL, s, c, NULL, "SSL_CIPHER"),
+                     ssl_var_lookup(NULL, s, c, NULL, "SSL_CIPHER_USEKEYSIZE"),
+                     ssl_var_lookup(NULL, s, c, NULL, "SSL_CIPHER_ALGKEYSIZE"));
+    }
+}
+
+/*
+ * This callback function is executed while OpenSSL processes the SSL
+ * handshake and does SSL record layer stuff.  It's used to trap
+ * client-initiated renegotiations, and for dumping everything to the
+ * log.
+ */
+void ssl_callback_Info(MODSSL_INFO_CB_ARG_TYPE ssl, int where, int rc)
+{
+    conn_rec *c;
+    server_rec *s;
+    SSLConnRec *scr;
+
+    /* Retrieve the conn_rec and the associated SSLConnRec. */
+    if ((c = (conn_rec *)SSL_get_app_data((SSL *)ssl)) == NULL) {
+        return;
+    }
+
+    if ((scr = myConnConfig(c)) == NULL) {
+        return;
+    }
+
+    /* If the reneg state is to reject renegotiations, check the SSL
+     * state machine and move to ABORT if a Client Hello is being
+     * read. */
+    if ((where & SSL_CB_ACCEPT_LOOP) && scr->reneg_state == RENEG_REJECT) {
+        int state = SSL_get_state((SSL *)ssl);
+        
+        if (state == SSL3_ST_SR_CLNT_HELLO_A 
+            || state == SSL23_ST_SR_CLNT_HELLO_A) {
+            scr->reneg_state = RENEG_ABORT;
+            ap_log_cerror(APLOG_MARK, APLOG_ERR, 0, c,
+                          "rejecting client initiated renegotiation");
+        }
+    }
+    /* If the first handshake is complete, change state to reject any
+     * subsequent client-initated renegotiation. */
+    else if ((where & SSL_CB_HANDSHAKE_DONE) && scr->reneg_state == RENEG_INIT) {
+        scr->reneg_state = RENEG_REJECT;
+    }
+
+    s = c->base_server;
+    if (s && s->loglevel >= APLOG_DEBUG) {
+        log_tracing_state(ssl, c, s, where, rc);
+    }
+}