Adding upstream version 2.4.58.upstream/2.4.58

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 969 insertions, 0 deletions

diff --git a/modules/ssl/ssl_util_stapling.c b/modules/ssl/ssl_util_stapling.c
new file mode 100644
index 0000000..c9d1d8e
--- /dev/null
+++ b/modules/ssl/ssl_util_stapling.c
@@ -0,0 +1,969 @@
+/* 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_stapling.c
+ *  OCSP Stapling Support
+ */
+                             /* ``Where's the spoons?
+                                  Where's the spoons?
+                                  Where's the bloody spoons?''
+                                            -- Alexei Sayle          */
+
+#include "ssl_private.h"
+#include "ap_mpm.h"
+#include "apr_thread_mutex.h"
+#include "mod_ssl_openssl.h"
+
+APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(ssl, SSL, int, init_stapling_status,
+                                    (server_rec *s, apr_pool_t *p, 
+                                     X509 *cert, X509 *issuer),
+                                     (s, p, cert, issuer),
+                                    DECLINED, DECLINED)
+
+APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(ssl, SSL, int, get_stapling_status,
+                                    (unsigned char **pder, int *pderlen, 
+                                     conn_rec *c, server_rec *s, X509 *cert),
+                                     (pder, pderlen, c, s, cert), 
+                                    DECLINED, DECLINED)
+                         
+
+#ifdef HAVE_OCSP_STAPLING
+
+static int stapling_cache_mutex_on(server_rec *s);
+static int stapling_cache_mutex_off(server_rec *s);
+
+static int stapling_cb(SSL *ssl, void *arg);
+
+/**
+ * Maximum OCSP stapling response size. This should be the response for a
+ * single certificate and will typically include the responder certificate chain
+ * so 10K should be more than enough.
+ *
+ */
+
+#define MAX_STAPLING_DER 10240
+
+/* Cached info stored in the global stapling_certinfo hash. */
+typedef struct {
+    /* Index in session cache (SHA-1 digest of DER encoded certificate) */
+    UCHAR idx[SHA_DIGEST_LENGTH];
+    /* Certificate ID for OCSP request */
+    OCSP_CERTID *cid;
+    /* URI of the OCSP responder */
+    char *uri;
+} certinfo;
+
+static apr_status_t ssl_stapling_certid_free(void *data)
+{
+    OCSP_CERTID *cid = data;
+
+    if (cid) {
+        OCSP_CERTID_free(cid);
+    }
+
+    return APR_SUCCESS;
+}
+
+static apr_hash_t *stapling_certinfo;
+
+void ssl_stapling_certinfo_hash_init(apr_pool_t *p)
+{
+    stapling_certinfo = apr_hash_make(p);
+}
+
+static X509 *stapling_get_issuer(modssl_ctx_t *mctx, X509 *x)
+{
+    X509 *issuer = NULL;
+    int i;
+    X509_STORE *st = SSL_CTX_get_cert_store(mctx->ssl_ctx);
+    X509_STORE_CTX *inctx;
+    STACK_OF(X509) *extra_certs = NULL;
+
+#ifdef OPENSSL_NO_SSL_INTERN
+    SSL_CTX_get_extra_chain_certs(mctx->ssl_ctx, &extra_certs);
+#else
+    extra_certs = mctx->ssl_ctx->extra_certs;
+#endif
+
+    for (i = 0; i < sk_X509_num(extra_certs); i++) {
+        issuer = sk_X509_value(extra_certs, i);
+        if (X509_check_issued(issuer, x) == X509_V_OK) {
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+            CRYPTO_add(&issuer->references, 1, CRYPTO_LOCK_X509);
+#else
+            X509_up_ref(issuer);
+#endif
+            return issuer;
+        }
+    }
+
+    inctx = X509_STORE_CTX_new();
+    if (!X509_STORE_CTX_init(inctx, st, NULL, NULL))
+        return 0;
+    if (X509_STORE_CTX_get1_issuer(&issuer, inctx, x) <= 0)
+        issuer = NULL;
+    X509_STORE_CTX_cleanup(inctx);
+    X509_STORE_CTX_free(inctx);
+    return issuer;
+}
+
+int ssl_stapling_init_cert(server_rec *s, apr_pool_t *p, apr_pool_t *ptemp,
+                           modssl_ctx_t *mctx, X509 *x)
+{
+    UCHAR idx[SHA_DIGEST_LENGTH];
+    certinfo *cinf = NULL;
+    X509 *issuer = NULL;
+    OCSP_CERTID *cid = NULL;
+    STACK_OF(OPENSSL_STRING) *aia = NULL;
+    const char *pem = NULL;
+    int rv = 1; /* until further notice */
+
+    if (x == NULL)
+        return 0;
+
+    if (!(issuer = stapling_get_issuer(mctx, x))) {
+        /* In Apache pre 2.4.40, we use to come here only when mod_ssl stapling
+         * was enabled. With the new hooks, we give other modules the chance
+         * to provide stapling status. However, we do not want to log ssl errors
+         * where we did not do so in the past. */
+        if (mctx->stapling_enabled == TRUE) {
+            ssl_log_xerror(SSLLOG_MARK, APLOG_ERR, 0, ptemp, s, x, APLOGNO(02217)
+                           "ssl_stapling_init_cert: can't retrieve issuer "
+                           "certificate!");
+            return 0;
+        }
+        return 1;
+    }
+
+    if (X509_digest(x, EVP_sha1(), idx, NULL) != 1) {
+        rv = 0;
+        goto cleanup;
+    }
+
+    if (modssl_cert_get_pem(ptemp, x, issuer, &pem) != APR_SUCCESS) {
+        rv = 0;
+        goto cleanup;
+    }
+
+    if (ap_ssl_ocsp_prime(s, p, (const char*)idx, sizeof(idx), pem) == APR_SUCCESS
+        || ssl_run_init_stapling_status(s, p, x, issuer) == OK) {
+        /* Someone's taken over or mod_ssl's own implementation is not enabled */
+        if (mctx->stapling_enabled != TRUE) {
+            SSL_CTX_set_tlsext_status_cb(mctx->ssl_ctx, stapling_cb);
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(10177) "OCSP stapling added via hook");
+        }
+        goto cleanup;
+    }
+    
+    if (mctx->stapling_enabled != TRUE) {
+        /* mod_ssl's own implementation is not enabled */
+        goto cleanup;
+    }
+    
+    cinf = apr_hash_get(stapling_certinfo, idx, sizeof(idx));
+    if (cinf) {
+        /* 
+         * We already parsed the certificate, and no OCSP URI was found.
+         * The certificate might be used for multiple vhosts, though,
+         * so we check for a ForceURL for this vhost.
+         */
+        if (!cinf->uri && !mctx->stapling_force_url) {
+            ssl_log_xerror(SSLLOG_MARK, APLOG_ERR, 0, ptemp, s, x,
+                           APLOGNO(02814) "ssl_stapling_init_cert: no OCSP URI "
+                           "in certificate and no SSLStaplingForceURL "
+                           "configured for server %s", mctx->sc->vhost_id);
+            rv = 0;
+        }
+        goto cleanup;
+    }
+
+    cid = OCSP_cert_to_id(NULL, x, issuer);
+    if (!cid) {
+        ssl_log_xerror(SSLLOG_MARK, APLOG_ERR, 0, ptemp, s, x, APLOGNO(02815)
+                       "ssl_stapling_init_cert: can't create CertID "
+                       "for OCSP request");
+        rv = 0;
+        goto cleanup;
+    }
+
+    aia = X509_get1_ocsp(x);
+    if (!aia && !mctx->stapling_force_url) {
+        OCSP_CERTID_free(cid);
+        ssl_log_xerror(SSLLOG_MARK, APLOG_ERR, 0, ptemp, s, x,
+                       APLOGNO(02218) "ssl_stapling_init_cert: no OCSP URI "
+                       "in certificate and no SSLStaplingForceURL set");
+        rv = 0;
+        goto cleanup;
+    }
+
+    /* At this point, we have determined that there's something to store */
+    cinf = apr_pcalloc(p, sizeof(certinfo));
+    memcpy (cinf->idx, idx, sizeof(idx));
+    cinf->cid = cid;
+    /* make sure cid is also freed at pool cleanup */
+    apr_pool_cleanup_register(p, cid, ssl_stapling_certid_free,
+                              apr_pool_cleanup_null);
+    if (aia) {
+       /* allocate uri from the pconf pool */
+       cinf->uri = apr_pstrdup(p, sk_OPENSSL_STRING_value(aia, 0));
+       X509_email_free(aia);
+    }
+
+    ssl_log_xerror(SSLLOG_MARK, APLOG_TRACE1, 0, ptemp, s, x,
+                   "ssl_stapling_init_cert: storing certinfo for server %s",
+                   mctx->sc->vhost_id);
+
+    apr_hash_set(stapling_certinfo, cinf->idx, sizeof(cinf->idx), cinf);
+
+cleanup:
+    X509_free(issuer);
+    return rv;
+}
+
+static certinfo *stapling_get_certinfo(server_rec *s, UCHAR *idx, apr_size_t idx_len,
+                                       modssl_ctx_t *mctx, SSL *ssl)
+{
+    certinfo *cinf;
+    cinf = apr_hash_get(stapling_certinfo, idx, idx_len);
+    if (cinf && cinf->cid)
+        return cinf;
+    ap_log_error(APLOG_MARK, APLOG_INFO, 0, s, APLOGNO(01926)
+                 "stapling_get_certinfo: stapling not supported for certificate");
+    return NULL;
+}
+
+/*
+ * OCSP response caching code. The response is preceded by a flag value
+ * which indicates whether the response was invalid when it was stored.
+ * the purpose of this flag is to avoid repeated queries to a server
+ * which has given an invalid response while allowing a response which
+ * has subsequently become invalid to be retried immediately.
+ *
+ * The key for the cache is the hash of the certificate the response
+ * is for.
+ */
+static BOOL stapling_cache_response(server_rec *s, modssl_ctx_t *mctx,
+                                    OCSP_RESPONSE *rsp, certinfo *cinf,
+                                    BOOL ok, apr_pool_t *pool)
+{
+    SSLModConfigRec *mc = myModConfig(s);
+    unsigned char resp_der[MAX_STAPLING_DER]; /* includes one-byte flag + response */
+    unsigned char *p;
+    int resp_derlen, stored_len;
+    BOOL rv;
+    apr_time_t expiry;
+
+    resp_derlen = i2d_OCSP_RESPONSE(rsp, NULL);
+
+    if (resp_derlen <= 0) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01927)
+                     "OCSP stapling response encode error??");
+        return FALSE;
+    }
+
+    stored_len = resp_derlen + 1; /* response + ok flag */
+    if (stored_len > sizeof resp_der) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01928)
+                     "OCSP stapling response too big (%u bytes)", resp_derlen);
+        return FALSE;
+    }
+
+    p = resp_der;
+
+    /* TODO: potential optimization; _timeout members as apr_interval_time_t */
+    if (ok == TRUE) {
+        *p++ = 1;
+        expiry = apr_time_from_sec(mctx->stapling_cache_timeout);
+    }
+    else {
+        *p++ = 0;
+        expiry = apr_time_from_sec(mctx->stapling_errcache_timeout);
+    }
+
+    expiry += apr_time_now();
+
+    i2d_OCSP_RESPONSE(rsp, &p);
+
+    if (mc->stapling_cache->flags & AP_SOCACHE_FLAG_NOTMPSAFE)
+        stapling_cache_mutex_on(s);
+    rv = mc->stapling_cache->store(mc->stapling_cache_context, s,
+                                   cinf->idx, sizeof(cinf->idx),
+                                   expiry, resp_der, stored_len, pool);
+    if (mc->stapling_cache->flags & AP_SOCACHE_FLAG_NOTMPSAFE)
+        stapling_cache_mutex_off(s);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01929)
+                     "stapling_cache_response: OCSP response session store error!");
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+static void stapling_get_cached_response(server_rec *s, OCSP_RESPONSE **prsp,
+                                         BOOL *pok, certinfo *cinf,
+                                         apr_pool_t *pool)
+{
+    SSLModConfigRec *mc = myModConfig(s);
+    apr_status_t rv;
+    OCSP_RESPONSE *rsp;
+    unsigned char resp_der[MAX_STAPLING_DER];
+    const unsigned char *p;
+    unsigned int resp_derlen = MAX_STAPLING_DER;
+
+    if (mc->stapling_cache->flags & AP_SOCACHE_FLAG_NOTMPSAFE)
+        stapling_cache_mutex_on(s);
+    rv = mc->stapling_cache->retrieve(mc->stapling_cache_context, s,
+                                      cinf->idx, sizeof(cinf->idx),
+                                      resp_der, &resp_derlen, pool);
+    if (mc->stapling_cache->flags & AP_SOCACHE_FLAG_NOTMPSAFE)
+        stapling_cache_mutex_off(s);
+    if (rv != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01930)
+                     "stapling_get_cached_response: cache miss");
+        return;
+    }
+    if (resp_derlen <= 1) {
+        /* should-not-occur; must have at least valid-when-stored flag +
+         * OCSPResponseStatus
+         */
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01931)
+                     "stapling_get_cached_response: response length invalid??");
+        return;
+    }
+    p = resp_der;
+    if (*p) /* valid when stored */
+        *pok = TRUE;
+    else
+        *pok = FALSE;
+    p++;
+    resp_derlen--;
+    rsp = d2i_OCSP_RESPONSE(NULL, &p, resp_derlen);
+    if (!rsp) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01932)
+                     "stapling_get_cached_response: response parse error??");
+        return;
+    }
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01933)
+                 "stapling_get_cached_response: cache hit");
+
+    *prsp = rsp;
+}
+
+static int stapling_set_response(SSL *ssl, OCSP_RESPONSE *rsp)
+{
+    int rspderlen;
+    unsigned char *rspder = NULL;
+
+    rspderlen = i2d_OCSP_RESPONSE(rsp, &rspder);
+    if (rspderlen <= 0)
+        return 0;
+    SSL_set_tlsext_status_ocsp_resp(ssl, rspder, rspderlen);
+    return 1;
+}
+
+static int stapling_check_response(server_rec *s, modssl_ctx_t *mctx,
+                                   certinfo *cinf, OCSP_RESPONSE *rsp,
+                                   BOOL *pok)
+{
+    int status = V_OCSP_CERTSTATUS_UNKNOWN;
+    int reason = OCSP_REVOKED_STATUS_NOSTATUS;
+    OCSP_BASICRESP *bs = NULL;
+    ASN1_GENERALIZEDTIME *rev, *thisupd, *nextupd;
+    int response_status = OCSP_response_status(rsp);
+    int rv = SSL_TLSEXT_ERR_OK;
+
+    if (pok)
+        *pok = FALSE;
+    /* Check to see if response is an error. If so we automatically accept
+     * it because it would have expired from the cache if it was time to
+     * retry.
+     */
+    if (response_status != OCSP_RESPONSE_STATUS_SUCCESSFUL) {
+        if (mctx->stapling_return_errors)
+            return SSL_TLSEXT_ERR_OK;
+        else
+            return SSL_TLSEXT_ERR_NOACK;
+    }
+
+    bs = OCSP_response_get1_basic(rsp);
+    if (bs == NULL) {
+        /* If we can't parse response just pass it to client */
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01934)
+                     "stapling_check_response: Error Parsing Response!");
+        return SSL_TLSEXT_ERR_OK;
+    }
+
+    if (!OCSP_resp_find_status(bs, cinf->cid, &status, &reason, &rev,
+                               &thisupd, &nextupd)) {
+        /* If ID not present pass back to client (if configured so) */
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01935)
+                     "stapling_check_response: certificate ID not present in response!");
+        if (mctx->stapling_return_errors == FALSE)
+            rv = SSL_TLSEXT_ERR_NOACK;
+    }
+    else {
+        if (OCSP_check_validity(thisupd, nextupd,
+                                mctx->stapling_resptime_skew,
+                                mctx->stapling_resp_maxage)) {
+            if (pok)
+                *pok = TRUE;
+        }
+        else {
+            /* If pok is not NULL response was direct from a responder and
+             * the times should be valide. If pok is NULL the response was
+             * retrieved from cache and it is expected to subsequently expire
+             */
+            if (pok) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01936)
+                             "stapling_check_response: response times invalid");
+            }
+            else {
+                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01937)
+                             "stapling_check_response: cached response expired");
+            }
+
+            rv = SSL_TLSEXT_ERR_NOACK;
+        }
+
+        if (status != V_OCSP_CERTSTATUS_GOOD && pok) {
+            char snum[MAX_STRING_LEN] = { '\0' };
+            BIO *bio = BIO_new(BIO_s_mem());
+
+            if (bio) {
+                int n;
+                ASN1_INTEGER *pserial;
+                OCSP_id_get0_info(NULL, NULL, NULL, &pserial, cinf->cid);
+                if ((i2a_ASN1_INTEGER(bio, pserial) != -1) &&
+                    ((n = BIO_read(bio, snum, sizeof snum - 1)) > 0))
+                    snum[n] = '\0';
+                BIO_free(bio);
+            }
+
+            ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(02969)
+                         "stapling_check_response: response has certificate "
+                         "status %s (reason: %s) for serial number %s",
+                         OCSP_cert_status_str(status),
+                         (reason != OCSP_REVOKED_STATUS_NOSTATUS) ?
+                         OCSP_crl_reason_str(reason) : "n/a",
+                         snum[0] ? snum : "[n/a]");
+        }
+    }
+
+    OCSP_BASICRESP_free(bs);
+
+    return rv;
+}
+
+static BOOL stapling_renew_response(server_rec *s, modssl_ctx_t *mctx, SSL *ssl,
+                                    certinfo *cinf, OCSP_RESPONSE **prsp,
+                                    BOOL *pok, apr_pool_t *pool)
+{
+    conn_rec *conn      = (conn_rec *)SSL_get_app_data(ssl);
+    apr_pool_t *vpool;
+    OCSP_REQUEST *req = NULL;
+    OCSP_CERTID *id = NULL;
+    STACK_OF(X509_EXTENSION) *exts;
+    int i;
+    BOOL rv = TRUE;
+    const char *ocspuri;
+    apr_uri_t uri;
+
+    *prsp = NULL;
+    /* Build up OCSP query from server certificate info */
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01938)
+                 "stapling_renew_response: querying responder");
+
+    req = OCSP_REQUEST_new();
+    if (!req)
+        goto err;
+    id = OCSP_CERTID_dup(cinf->cid);
+    if (!id)
+        goto err;
+    if (!OCSP_request_add0_id(req, id))
+        goto err;
+    id = NULL;
+    /* Add any extensions to the request */
+    SSL_get_tlsext_status_exts(ssl, &exts);
+    for (i = 0; i < sk_X509_EXTENSION_num(exts); i++) {
+        X509_EXTENSION *ext = sk_X509_EXTENSION_value(exts, i);
+        if (!OCSP_REQUEST_add_ext(req, ext, -1))
+            goto err;
+    }
+
+    if (mctx->stapling_force_url)
+        ocspuri = mctx->stapling_force_url;
+    else
+        ocspuri = cinf->uri;
+
+    if (!ocspuri) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(02621)
+                     "stapling_renew_response: no uri for responder");
+        rv = FALSE;
+        goto done;
+    }
+
+    /* Create a temporary pool to constrain memory use */
+    apr_pool_create(&vpool, conn->pool);
+    apr_pool_tag(vpool, "modssl_stapling_renew");
+
+    if (apr_uri_parse(vpool, ocspuri, &uri) != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01939)
+                     "stapling_renew_response: Error parsing uri %s",
+                      ocspuri);
+        rv = FALSE;
+        goto done;
+    }
+    else if (strcmp(uri.scheme, "http")) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01940)
+                     "stapling_renew_response: Unsupported uri %s", ocspuri);
+        rv = FALSE;
+        goto done;
+    }
+
+    if (!uri.port) {
+        uri.port = apr_uri_port_of_scheme(uri.scheme);
+    }
+
+    *prsp = modssl_dispatch_ocsp_request(&uri, mctx->stapling_responder_timeout,
+                                         req, conn, vpool);
+
+    apr_pool_destroy(vpool);
+
+    if (!*prsp) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01941)
+                     "stapling_renew_response: responder error");
+        if (mctx->stapling_fake_trylater) {
+            *prsp = OCSP_response_create(OCSP_RESPONSE_STATUS_TRYLATER, NULL);
+        }
+        else {
+            goto done;
+        }
+    }
+    else {
+        int response_status = OCSP_response_status(*prsp);
+
+        if (response_status == OCSP_RESPONSE_STATUS_SUCCESSFUL) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01942)
+                        "stapling_renew_response: query response received");
+            stapling_check_response(s, mctx, cinf, *prsp, pok);
+            if (*pok == FALSE) {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01943)
+                             "stapling_renew_response: error in retrieved response!");
+            }
+        }
+        else {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01944)
+                         "stapling_renew_response: responder error %s",
+                         OCSP_response_status_str(response_status));
+            *pok = FALSE;
+        }
+    }
+    if (stapling_cache_response(s, mctx, *prsp, cinf, *pok, pool) == FALSE) {
+        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01945)
+                     "stapling_renew_response: error caching response!");
+    }
+
+done:
+    if (id)
+        OCSP_CERTID_free(id);
+    if (req)
+        OCSP_REQUEST_free(req);
+    return rv;
+err:
+    rv = FALSE;
+    goto done;
+}
+
+/*
+ * SSL stapling mutex operations. Similar to SSL mutex except mutexes are
+ * mandatory if stapling is enabled.
+ */
+static int ssl_stapling_mutex_init(server_rec *s, apr_pool_t *p)
+{
+    SSLModConfigRec *mc = myModConfig(s);
+    SSLSrvConfigRec *sc = mySrvConfig(s);
+    apr_status_t rv;
+
+    /* already init or stapling not enabled? */
+    if (mc->stapling_refresh_mutex || sc->server->stapling_enabled != TRUE) {
+        return TRUE;
+    }
+
+    /* need a cache mutex? */
+    if (mc->stapling_cache->flags & AP_SOCACHE_FLAG_NOTMPSAFE) {
+        if ((rv = ap_global_mutex_create(&mc->stapling_cache_mutex, NULL,
+                                         SSL_STAPLING_CACHE_MUTEX_TYPE, NULL, s,
+                                         s->process->pool, 0)) != APR_SUCCESS) {
+            return FALSE;
+        }
+    }
+
+    /* always need stapling_refresh_mutex */
+    if ((rv = ap_global_mutex_create(&mc->stapling_refresh_mutex, NULL,
+                                     SSL_STAPLING_REFRESH_MUTEX_TYPE, NULL, s,
+                                     s->process->pool, 0)) != APR_SUCCESS) {
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+static int stapling_mutex_reinit_helper(server_rec *s, apr_pool_t *p, 
+                                        apr_global_mutex_t **mutex,
+                                        const char *type)
+{
+    apr_status_t rv;
+    const char *lockfile;
+
+    lockfile = apr_global_mutex_lockfile(*mutex);
+    if ((rv = apr_global_mutex_child_init(mutex,
+                                          lockfile, p)) != APR_SUCCESS) {
+        if (lockfile) {
+            ap_log_error(APLOG_MARK, APLOG_ERR, rv, s, APLOGNO(01946)
+                         "Cannot reinit %s mutex with file `%s'",
+                         type, lockfile);
+        }
+        else {
+            ap_log_error(APLOG_MARK, APLOG_WARNING, rv, s, APLOGNO(01947)
+                         "Cannot reinit %s mutex", type);
+        }
+        return FALSE;
+    }
+    return TRUE;
+}
+
+int ssl_stapling_mutex_reinit(server_rec *s, apr_pool_t *p)
+{
+    SSLModConfigRec *mc = myModConfig(s);
+
+    if (mc->stapling_cache_mutex != NULL
+        && stapling_mutex_reinit_helper(s, p, &mc->stapling_cache_mutex,
+                                        SSL_STAPLING_CACHE_MUTEX_TYPE) == FALSE) {
+        return FALSE;
+    }
+
+    if (mc->stapling_refresh_mutex != NULL
+        && stapling_mutex_reinit_helper(s, p, &mc->stapling_refresh_mutex,
+                                        SSL_STAPLING_REFRESH_MUTEX_TYPE) == FALSE) {
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+static int stapling_mutex_on(server_rec *s, apr_global_mutex_t *mutex,
+                             const char *name)
+{
+    apr_status_t rv;
+
+    if ((rv = apr_global_mutex_lock(mutex)) != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, rv, s, APLOGNO(01948)
+                     "Failed to acquire OCSP %s lock", name);
+        return FALSE;
+    }
+    return TRUE;
+}
+
+static int stapling_mutex_off(server_rec *s, apr_global_mutex_t *mutex,
+                              const char *name)
+{
+    apr_status_t rv;
+
+    if ((rv = apr_global_mutex_unlock(mutex)) != APR_SUCCESS) {
+        ap_log_error(APLOG_MARK, APLOG_WARNING, rv, s, APLOGNO(01949)
+                     "Failed to release OCSP %s lock", name);
+        return FALSE;
+    }
+    return TRUE;
+}
+
+static int stapling_cache_mutex_on(server_rec *s)
+{
+    SSLModConfigRec *mc = myModConfig(s);
+
+    return stapling_mutex_on(s, mc->stapling_cache_mutex,
+                             SSL_STAPLING_CACHE_MUTEX_TYPE);
+}
+
+static int stapling_cache_mutex_off(server_rec *s)
+{
+    SSLModConfigRec *mc = myModConfig(s);
+
+    return stapling_mutex_off(s, mc->stapling_cache_mutex,
+                              SSL_STAPLING_CACHE_MUTEX_TYPE);
+}
+
+static int stapling_refresh_mutex_on(server_rec *s)
+{
+    SSLModConfigRec *mc = myModConfig(s);
+
+    return stapling_mutex_on(s, mc->stapling_refresh_mutex,
+                             SSL_STAPLING_REFRESH_MUTEX_TYPE);
+}
+
+static int stapling_refresh_mutex_off(server_rec *s)
+{
+    SSLModConfigRec *mc = myModConfig(s);
+
+    return stapling_mutex_off(s, mc->stapling_refresh_mutex,
+                              SSL_STAPLING_REFRESH_MUTEX_TYPE);
+}
+
+static int get_and_check_cached_response(server_rec *s, modssl_ctx_t *mctx,
+                                         OCSP_RESPONSE **rsp, BOOL *pok,
+                                         certinfo *cinf, apr_pool_t *p)
+{
+    BOOL ok = FALSE;
+    int rv;
+
+    AP_DEBUG_ASSERT(*rsp == NULL);
+
+    /* Check to see if we already have a response for this certificate */
+    stapling_get_cached_response(s, rsp, &ok, cinf, p);
+
+    if (*rsp) {
+        /* see if response is acceptable */
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01953)
+                     "stapling_cb: retrieved cached response");
+        rv = stapling_check_response(s, mctx, cinf, *rsp, NULL);
+        if (rv == SSL_TLSEXT_ERR_ALERT_FATAL) {
+            OCSP_RESPONSE_free(*rsp);
+            *rsp = NULL;
+            return SSL_TLSEXT_ERR_ALERT_FATAL;
+        }
+        else if (rv == SSL_TLSEXT_ERR_NOACK) {
+            /* Error in response. If this error was not present when it was
+             * stored (i.e. response no longer valid) then it can be
+             * renewed straight away.
+             *
+             * If the error *was* present at the time it was stored then we
+             * don't renew the response straight away; we just wait for the
+             * cached response to expire.
+             */
+            if (ok) {
+                OCSP_RESPONSE_free(*rsp);
+                *rsp = NULL;
+            }
+            else if (!mctx->stapling_return_errors) {
+                OCSP_RESPONSE_free(*rsp);
+                *rsp = NULL;
+                *pok = FALSE;
+                return SSL_TLSEXT_ERR_NOACK;
+            }
+        }
+    }
+    return 0;
+}
+
+typedef struct {
+    unsigned char *data;
+    apr_size_t len;
+} ocsp_resp;
+
+static void copy_ocsp_resp(const unsigned char *der, apr_size_t der_len, void *userdata)
+{
+    ocsp_resp *resp = userdata;
+
+    resp->len = 0;
+    resp->data = der? OPENSSL_malloc(der_len) : NULL;
+    if (resp->data) {
+        memcpy(resp->data, der, der_len);
+        resp->len = der_len;
+    }
+}
+
+/* Certificate Status callback. This is called when a client includes a
+ * certificate status request extension.
+ *
+ * Check for cached responses in session cache. If valid send back to
+ * client.  If absent or no longer valid, query responder and update
+ * cache.
+ */
+static int stapling_cb(SSL *ssl, void *arg)
+{
+    conn_rec *conn      = (conn_rec *)SSL_get_app_data(ssl);
+    server_rec *s       = mySrvFromConn(conn);
+    SSLSrvConfigRec *sc = mySrvConfig(s);
+    modssl_ctx_t *mctx  = myConnCtxConfig(conn, sc);
+    UCHAR idx[SHA_DIGEST_LENGTH];
+    ocsp_resp resp;
+    certinfo *cinf = NULL;
+    OCSP_RESPONSE *rsp = NULL;
+    int rv;
+    BOOL ok = TRUE;
+    X509 *x;
+    int rspderlen, provided = 0;
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01951)
+                 "stapling_cb: OCSP Stapling callback called");
+
+    x = SSL_get_certificate(ssl);
+    if (x == NULL) {
+        return SSL_TLSEXT_ERR_NOACK;
+    }
+
+    if (X509_digest(x, EVP_sha1(), idx, NULL) != 1) {
+        return SSL_TLSEXT_ERR_NOACK;
+    }
+
+    if (ap_ssl_ocsp_get_resp(s, conn, (const char*)idx, sizeof(idx),
+                             copy_ocsp_resp, &resp) == APR_SUCCESS) {
+        provided = 1;
+    }
+    else if (ssl_run_get_stapling_status(&resp.data, &rspderlen, conn, s, x) == APR_SUCCESS) {
+        resp.len = (apr_size_t)rspderlen;
+        provided = 1;
+    }
+
+    if (provided) {
+        /* a hook handles stapling for this certificate and determines the response */
+        if (resp.data == NULL || resp.len == 0) {
+            return SSL_TLSEXT_ERR_NOACK;
+        }
+        SSL_set_tlsext_status_ocsp_resp(ssl, resp.data, (int)resp.len);
+        return SSL_TLSEXT_ERR_OK;
+    }
+    
+    if (sc->server->stapling_enabled != TRUE) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01950)
+                     "stapling_cb: OCSP Stapling disabled");
+        return SSL_TLSEXT_ERR_NOACK;
+    }
+
+    if ((cinf = stapling_get_certinfo(s, idx, sizeof(idx), mctx, ssl)) == NULL) {
+        return SSL_TLSEXT_ERR_NOACK;
+    }
+
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01952)
+                 "stapling_cb: retrieved cached certificate data");
+
+    rv = get_and_check_cached_response(s, mctx, &rsp, &ok, cinf, conn->pool);
+    if (rv != 0) {
+        return rv;
+    }
+
+    if (rsp == NULL) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01954)
+                     "stapling_cb: renewing cached response");
+        stapling_refresh_mutex_on(s);
+        /* Maybe another request refreshed the OCSP response while this
+         * thread waited for the mutex.  Check again.
+         */
+        rv = get_and_check_cached_response(s, mctx, &rsp, &ok, cinf,
+                                           conn->pool);
+        if (rv != 0) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(03236)
+                         "stapling_cb: error checking for cached response "
+                         "after obtaining refresh mutex");
+            stapling_refresh_mutex_off(s);
+            return rv;
+        }
+        else if (rsp) {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(03237)
+                         "stapling_cb: don't need to refresh cached response "
+                         "after obtaining refresh mutex");
+            stapling_refresh_mutex_off(s);
+        }
+        else {
+            ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(03238)
+                         "stapling_cb: still must refresh cached response "
+                         "after obtaining refresh mutex");
+            rv = stapling_renew_response(s, mctx, ssl, cinf, &rsp, &ok,
+                                         conn->pool);
+            stapling_refresh_mutex_off(s);
+
+            if (rv == TRUE) {
+                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(03040)
+                             "stapling_cb: success renewing response");
+            }
+            else {
+                ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(01955)
+                             "stapling_cb: fatal error renewing response");
+                return SSL_TLSEXT_ERR_ALERT_FATAL;
+            }
+        }
+    }
+
+    if (rsp && ((ok == TRUE) || (mctx->stapling_return_errors == TRUE))) {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01956)
+                     "stapling_cb: setting response");
+        if (!stapling_set_response(ssl, rsp)) {
+            rv = SSL_TLSEXT_ERR_ALERT_FATAL;
+        }
+        else {
+            rv = SSL_TLSEXT_ERR_OK;
+        }
+    }
+    else {
+        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01957)
+                     "stapling_cb: no suitable response available");
+        rv = SSL_TLSEXT_ERR_NOACK;
+    }
+    OCSP_RESPONSE_free(rsp); /* NULL safe */
+
+    return rv;
+}
+
+apr_status_t modssl_init_stapling(server_rec *s, apr_pool_t *p,
+                                  apr_pool_t *ptemp, modssl_ctx_t *mctx)
+{
+    SSL_CTX *ctx = mctx->ssl_ctx;
+    SSLModConfigRec *mc = myModConfig(s);
+
+    if (mc->stapling_cache == NULL) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(01958)
+                     "SSLStapling: no stapling cache available");
+        return ssl_die(s);
+    }
+    if (ssl_stapling_mutex_init(s, ptemp) == FALSE) {
+        ap_log_error(APLOG_MARK, APLOG_EMERG, 0, s, APLOGNO(01959)
+                     "SSLStapling: cannot initialise stapling mutex");
+        return ssl_die(s);
+    }
+    /* Set some default values for parameters if they are not set */
+    if (mctx->stapling_resptime_skew == UNSET) {
+        mctx->stapling_resptime_skew = 60 * 5;
+    }
+    if (mctx->stapling_cache_timeout == UNSET) {
+        mctx->stapling_cache_timeout = 3600;
+    }
+    if (mctx->stapling_return_errors == UNSET) {
+        mctx->stapling_return_errors = TRUE;
+    }
+    if (mctx->stapling_fake_trylater == UNSET) {
+        mctx->stapling_fake_trylater = TRUE;
+    }
+    if (mctx->stapling_errcache_timeout == UNSET) {
+        mctx->stapling_errcache_timeout = 600;
+    }
+    if (mctx->stapling_responder_timeout == UNSET) {
+        mctx->stapling_responder_timeout = 10 * APR_USEC_PER_SEC;
+    }
+
+    SSL_CTX_set_tlsext_status_cb(ctx, stapling_cb);
+    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(01960) "OCSP stapling initialized");
+    
+    return APR_SUCCESS;
+}
+
+#endif