Add new directive SSLCompression to disable SSL-level compression.

PR: 53219
Submitted by: Björn Jacke <bjoern j3e de>, Stefan Fritsch


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1345319 13f79535-47bb-0310-9956-ffa450edef68

CHANGES

@@ -1,6 +1,9 @@
                                                          -*- coding: utf-8 -*-
 Changes with Apache 2.5.0
 
+  *) mod_ssl: Add new directive SSLCompression to disable TLS-level
+     compression. PR 53219. [Björn Jacke <bjoern j3e de>, Stefan Fritsch]
+
   *) core: Make ap_regcomp() return AP_REG_ESPACE if out of memory.  Make
      ap_pregcomp() abort if out of memory. This raises the minimum PCRE
      requirement to version 6.0. PR 53284. [Stefan Fritsch]

docs/manual/mod/mod_ssl.xml

@@ -2382,4 +2382,20 @@ be protected with file permissions similar to those used for
 </usage>
 </directivesynopsis>
 
+<directivesynopsis>
+<name>SSLCompression</name>
+<description>Disallow compression on the SSL level</description>
+<syntax>SSLCompression on|off</syntax>
+<default>SSLCompression on</default>
+<contextlist><context>server config</context>
+<context>virtual host</context></contextlist>
+<compatibility>Available in httpd 2.5.0 and later, if using OpenSSL 0.9.8 or later;
+virtual host scope available if using OpenSSL 1.0.0 or later</compatibility>
+
+<usage>
+<p>This directive allows to disable compression on the SSL level.</p>
+</usage>
+</directivesynopsis>
+
+
 </modulesynopsis>

modules/ssl/mod_ssl.c

@@ -138,6 +138,9 @@ static const command_rec ssl_config_cmds[] = {
                 "('[+-][" SSL_PROTOCOLS "] ...' - see manual)")
     SSL_CMD_SRV(HonorCipherOrder, FLAG,
                 "Use the server's cipher ordering preference")
+    SSL_CMD_SRV(Compression, FLAG,
+                "Enable SSL level compression"
+                "(`on', `off')")
     SSL_CMD_SRV(InsecureRenegotiation, FLAG,
                 "Enable support for insecure renegotiation")
     SSL_CMD_ALL(UserName, TAKE1,

modules/ssl/ssl_engine_config.c

@@ -207,6 +207,7 @@ static SSLSrvConfigRec *ssl_config_server_new(apr_pool_t *p)
 #ifdef HAVE_FIPS
     sc->fips                   = UNSET;
 #endif
+    sc->compression            = UNSET;
 
     modssl_ctx_init_proxy(sc, p);
 
@@ -328,6 +329,7 @@ void *ssl_config_server_merge(apr_pool_t *p, void *basev, void *addv)
 #ifdef HAVE_FIPS
     cfgMergeBool(fips);
 #endif
+    cfgMergeBool(compression);
 
     modssl_ctx_cfg_merge_proxy(base->proxy, add->proxy, mrg->proxy);
 
@@ -663,6 +665,23 @@ static const char *ssl_cmd_check_file(cmd_parms *parms,
 
 }
 
+const char *ssl_cmd_SSLCompression(cmd_parms *cmd, void *dcfg, int flag)
+{
+#if defined(SSL_OP_NO_COMPRESSION) || OPENSSL_VERSION_NUMBER >= 0x00908000L
+    SSLSrvConfigRec *sc = mySrvConfig(cmd->server);
+#ifndef SSL_OP_NO_COMPRESSION
+    const char *err = ap_check_cmd_context(cmd, GLOBAL_ONLY);
+    if (err)
+        return "This version of openssl does not support configuring "
+               "compression within <VirtualHost> sections.";
+#endif
+    sc->compression = flag ? TRUE : FALSE;
+    return NULL;
+#else
+    return "Setting Compression mode unsupported; not implemented by the SSL library";
+#endif
+}
+
 const char *ssl_cmd_SSLHonorCipherOrder(cmd_parms *cmd, void *dcfg, int flag)
 {
 #ifdef SSL_OP_CIPHER_SERVER_PREFERENCE

modules/ssl/ssl_engine_init.c

@@ -622,6 +622,20 @@ static void ssl_init_ctx_protocol(server_rec *s,
     }
 #endif
 
+#ifdef SSL_OP_NO_COMPRESSION
+    /* OpenSSL >= 1.0 only */
+    if (sc->compression == FALSE) {
+        SSL_CTX_set_options(ctx, SSL_OP_NO_COMPRESSION);
+    }
+#elif OPENSSL_VERSION_NUMBER >= 0x00908000L
+    /* workaround for OpenSSL 0.9.8 */
+    if (sc->compression == FALSE) {
+        STACK_OF(SSL_COMP)* comp_methods;
+        comp_methods = SSL_COMP_get_compression_methods();
+        sk_SSL_COMP_zero(comp_methods);
+    }
+#endif
+
 #ifdef SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION
     if (sc->insecure_reneg == TRUE) {
         SSL_CTX_set_options(ctx, SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION);

modules/ssl/ssl_private.h

@@ -678,6 +678,7 @@ struct SSLSrvConfigRec {
 #ifdef HAVE_FIPS
     BOOL             fips;
 #endif
+    BOOL             compression;
 };
 
 /**
@@ -732,6 +733,7 @@ const char  *ssl_cmd_SSLCARevocationPath(cmd_parms *, void *, const char *);
 const char  *ssl_cmd_SSLCARevocationFile(cmd_parms *, void *, const char *);
 const char  *ssl_cmd_SSLCARevocationCheck(cmd_parms *, void *, const char *);
 const char  *ssl_cmd_SSLHonorCipherOrder(cmd_parms *cmd, void *dcfg, int flag);
+const char  *ssl_cmd_SSLCompression(cmd_parms *, void *, int flag);
 const char  *ssl_cmd_SSLVerifyClient(cmd_parms *, void *, const char *);
 const char  *ssl_cmd_SSLVerifyDepth(cmd_parms *, void *, const char *);
 const char  *ssl_cmd_SSLSessionCache(cmd_parms *, void *, const char *);