Remove deprecated option '--keysize'

This option has been deprecated in OpenVPN 2.4 and the ciphers that allow
using this option fall all into the SWEET32 category of ciphers with
64 bit block size.

Patch V2: Remove superflous check in OpenSSL codepath to check keysize

Signed-off-by: Arne Schwabe <arne@rfc2549.org>
Acked-by: Antonio Quartulli <antonio@openvpn.net>
Message-Id: <20210401123751.31756-1-arne@rfc2549.org>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg21943.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/config-msvc.h b/config-msvc.h
index 4db9efae2fc983996c6209aa3ab14f68267f8cbe..aea2628be7233cb46e13b2b594ea29385d35a02e 100644 (file)
--- a/config-msvc.h
+++ b/config-msvc.h
@@ -48,7 +48,6 @@
 #define HAVE_CHDIR 1
 #define HAVE_CHSIZE 1
 #define HAVE_CTIME 1
-#define HAVE_EVP_CIPHER_CTX_SET_KEY_LENGTH 1
 #define HAVE_IN_PKTINFO 1
 #define HAVE_MEMSET 1
 #define HAVE_PUTENV 1

diff --git a/configure.ac b/configure.ac
index 3cb9fc2fc2dd18e168e08a264cfb1e99acf5907e..7bc6c7b90a3449772e35c03a70960777f004ddc5 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -878,7 +878,7 @@ if test "${with_crypto_library}" = "openssl"; then
                )
        fi
 
-       AC_CHECK_FUNCS([SSL_CTX_new EVP_CIPHER_CTX_set_key_length],
+       AC_CHECK_FUNCS([SSL_CTX_new],
                                   ,
                                   [AC_MSG_ERROR([openssl check failed])]
        )

diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c
index 3a0bfbec4175a7891c2282a919e4b02e5b780778..b042514bf72a4e8aa9e60784aaa4709310f76351 100644 (file)
--- a/src/openvpn/crypto.c
+++ b/src/openvpn/crypto.c
@@ -739,7 +739,7 @@ warn_insecure_key_type(const char *ciphername, const cipher_kt_t *cipher)
  */
 void
 init_key_type(struct key_type *kt, const char *ciphername,
-              const char *authname, int keysize, bool tls_mode, bool warn)
+              const char *authname, bool tls_mode, bool warn)
 {
     bool aead_cipher = false;
 
@@ -756,10 +756,6 @@ init_key_type(struct key_type *kt, const char *ciphername,
         }
 
         kt->cipher_length = cipher_kt_key_size(kt->cipher);
-        if (keysize > 0 && keysize <= MAX_CIPHER_KEY_LENGTH)
-        {
-            kt->cipher_length = keysize;
-        }
 
         /* check legal cipher mode */
         aead_cipher = cipher_kt_mode_aead(kt->cipher);

diff --git a/src/openvpn/crypto.h b/src/openvpn/crypto.h
index 1ad669ce1a49a681092e8835d493efa3d80cceea..b8128c7f131dec396b3aec0ce0258b01e5dadf26 100644 (file)
--- a/src/openvpn/crypto.h
+++ b/src/openvpn/crypto.h
@@ -301,14 +301,12 @@ int read_key(struct key *key, const struct key_type *kt, struct buffer *buf);
  * @param kt          The struct key_type to initialize
  * @param ciphername  The name of the cipher to use
  * @param authname    The name of the HMAC digest to use
- * @param keysize     The length of the cipher key to use, in bytes.  Only valid
- *                    for ciphers that support variable length keys.
  * @param tls_mode    Specifies whether we are running in TLS mode, which allows
  *                    more ciphers than static key mode.
  * @param warn        Print warnings when null cipher / auth is used.
  */
 void init_key_type(struct key_type *kt, const char *ciphername,
-                   const char *authname, int keysize, bool tls_mode, bool warn);
+                   const char *authname, bool tls_mode, bool warn);
 
 /*
  * Key context functions

diff --git a/src/openvpn/crypto_openssl.c b/src/openvpn/crypto_openssl.c
index 573beaed749d3ab072d2a206c1f21af2e7dd96b4..f3e86863e3a5a1098b9d0782407f4fd8f39f65eb 100644 (file)
--- a/src/openvpn/crypto_openssl.c
+++ b/src/openvpn/crypto_openssl.c
@@ -292,10 +292,8 @@ show_available_ciphers(void)
 #ifndef ENABLE_SMALL
     printf("The following ciphers and cipher modes are available for use\n"
            "with " PACKAGE_NAME ".  Each cipher shown below may be used as a\n"
-           "parameter to the --data-ciphers (or --cipher) option.  The\n"
-           "default key size is shown as well as whether or not it can be\n"
-           "changed with the --keysize directive.  Using a GCM or CBC mode\n"
-           "is recommended.  In static key mode only CBC mode is allowed.\n\n");
+           "parameter to the --data-ciphers (or --cipher) option. In static \n"
+           "key mode only CBC mode is allowed.\n\n");
 #endif
 
     for (nid = 0; nid < 10000; ++nid)
@@ -776,12 +774,6 @@ cipher_ctx_init(EVP_CIPHER_CTX *ctx, const uint8_t *key, int key_len,
     {
         crypto_msg(M_FATAL, "EVP cipher init #1");
     }
-#ifdef HAVE_EVP_CIPHER_CTX_SET_KEY_LENGTH
-    if (!EVP_CIPHER_CTX_set_key_length(ctx, key_len))
-    {
-        crypto_msg(M_FATAL, "EVP set key size");
-    }
-#endif
     if (!EVP_CipherInit_ex(ctx, NULL, NULL, key, NULL, enc))
     {
         crypto_msg(M_FATAL, "EVP cipher init #2");

diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index 0751a0a6e0d5a91af627ee34927d14783d4a5d9c..04a7dcc8316863f72e8cd05efddd6997ae85a95a 100644 (file)
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -2599,7 +2599,7 @@ do_init_crypto_static(struct context *c, const unsigned int flags)
     {
         /* Get cipher & hash algorithms */
         init_key_type(&c->c1.ks.key_type, options->ciphername, options->authname,
-                      options->keysize, options->test_crypto, true);
+                      options->test_crypto, true);
 
         /* Read cipher and hmac keys from shared secret file */
         crypto_read_openvpn_key(&c->c1.ks.key_type, &c->c1.ks.static_key,
@@ -2772,7 +2772,7 @@ do_init_crypto_tls_c1(struct context *c)
             /* Do not warn if the if the cipher is used only in OCC */
             bool warn = !options->ncp_enabled || options->enable_ncp_fallback;
             init_key_type(&c->c1.ks.key_type, options->ciphername, options->authname,
-                          options->keysize, true, warn);
+                          true, warn);
         }
         /* Initialize PRNG with config-specified digest */
         prng_init(options->prng_hash, options->prng_nonce_secret_len);
@@ -4449,7 +4449,6 @@ inherit_context_child(struct context *dest,
     /* inherit pre-NCP ciphers */
     dest->options.ciphername = src->options.ciphername;
     dest->options.authname = src->options.authname;
-    dest->options.keysize = src->options.keysize;
 
     /* inherit auth-token */
     dest->c1.ks.auth_token_key = src->c1.ks.auth_token_key;

diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index 0aa891d98f0d6378b334829fb0ce9ed7705c47b8..eccb6c2e4885021f4abeeeced2b42e076d58b7bd 100644 (file)
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -531,10 +531,6 @@ static const char usage_message[] =
     "--ncp-disable   : (DEPRECATED) Disable cipher negotiation.\n"
     "--prng alg [nsl] : For PRNG, use digest algorithm alg, and\n"
     "                   nonce_secret_len=nsl.  Set alg=none to disable PRNG.\n"
-#ifdef HAVE_EVP_CIPHER_CTX_SET_KEY_LENGTH
-    "--keysize n     : (DEPRECATED) Size of cipher key in bits (optional).\n"
-    "                  If unspecified, defaults to cipher-specific default.\n"
-#endif
 #ifndef ENABLE_CRYPTO_MBEDTLS
     "--engine [name] : Enable OpenSSL hardware crypto engine functionality.\n"
 #endif
@@ -1733,7 +1729,6 @@ show_settings(const struct options *o)
     SHOW_STR(authname);
     SHOW_STR(prng_hash);
     SHOW_INT(prng_nonce_secret_len);
-    SHOW_INT(keysize);
 #ifndef ENABLE_CRYPTO_MBEDTLS
     SHOW_BOOL(engine);
 #endif /* ENABLE_CRYPTO_MBEDTLS */
@@ -2540,11 +2535,6 @@ options_postprocess_verify_ce(const struct options *options,
         }
     }
 
-    if (options->keysize)
-    {
-        msg(M_WARN, "WARNING: --keysize is DEPRECATED and will be removed in OpenVPN 2.6");
-    }
-
     /*
      * Check consistency of replay options
      */
@@ -3619,7 +3609,6 @@ pre_pull_save(struct options *o)
         /* NCP related options that can be overwritten by a push */
         o->pre_pull->ciphername = o->ciphername;
         o->pre_pull->authname = o->authname;
-        o->pre_pull->keysize = o->keysize;
 
         /* Ping related options should be reset to the config values on reconnect */
         o->pre_pull->ping_rec_timeout = o->ping_rec_timeout;
@@ -3675,7 +3664,6 @@ pre_pull_restore(struct options *o, struct gc_arena *gc)
 
         o->ciphername = pp->ciphername;
         o->authname = pp->authname;
-        o->keysize = pp->keysize;
 
         o->ping_rec_timeout = pp->ping_rec_timeout;
         o->ping_rec_timeout_action = pp->ping_rec_timeout_action;
@@ -3724,8 +3712,7 @@ calc_options_string_link_mtu(const struct options *o, const struct frame *frame)
             frame_add_to_extra_frame(&fake_frame, 64/8 + 64/8);
         }
 
-        init_key_type(&fake_kt, ciphername, o->authname, o->keysize, true,
-                      false);
+        init_key_type(&fake_kt, ciphername, o->authname, true, false);
 
         crypto_adjust_frame_parameters(&fake_frame, &fake_kt, o->replay,
                                        cipher_kt_mode_ofb_cfb(fake_kt.cipher));
@@ -3903,14 +3890,12 @@ options_string(const struct options *o,
 
         if (strcmp(o->ciphername, "BF-CBC") == 0)
         {
-            init_key_type(&kt, "none", o->authname, o->keysize, true,
-                          false);
+            init_key_type(&kt, "none", o->authname, true, false);
             keysize = 128;
         }
         else
         {
-            init_key_type(&kt, o->ciphername, o->authname, o->keysize, true,
-                          false);
+            init_key_type(&kt, o->ciphername, o->authname, true, false);
             ciphername = cipher_kt_name(kt.cipher);
             keysize = kt.cipher_length * 8;
         }
@@ -8122,21 +8107,6 @@ add_option(struct options *options,
         }
     }
 #endif /* ENABLE_CRYPTO_MBEDTLS */
-#ifdef HAVE_EVP_CIPHER_CTX_SET_KEY_LENGTH
-    else if (streq(p[0], "keysize") && p[1] && !p[2])
-    {
-        int keysize;
-
-        VERIFY_PERMISSION(OPT_P_NCP);
-        keysize = atoi(p[1]) / 8;
-        if (keysize < 0 || keysize > MAX_CIPHER_KEY_LENGTH)
-        {
-            msg(msglevel, "Bad keysize: %s", p[1]);
-            goto err;
-        }
-        options->keysize = keysize;
-    }
-#endif
 #ifdef ENABLE_PREDICTION_RESISTANCE
     else if (streq(p[0], "use-prediction-resistance") && !p[1])
     {

diff --git a/src/openvpn/options.h b/src/openvpn/options.h
index f3208c7192c90325907e28d12162f361d233ec7c..0114ac3be51c395acb99770c7ed3fbb044dd21cc 100644 (file)
--- a/src/openvpn/options.h
+++ b/src/openvpn/options.h
@@ -77,7 +77,6 @@ struct options_pre_pull
 
     const char* ciphername;
     const char* authname;
-    int keysize;
 
     int ping_send_timeout;
     int ping_rec_timeout;
@@ -521,7 +520,6 @@ struct options
     bool ncp_enabled;
     const char *ncp_ciphers;
     const char *authname;
-    int keysize;
     const char *prng_hash;
     int prng_nonce_secret_len;
     const char *engine;

diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
index 9b9ef6852136cd1770151792464fea15683d4fc7..0948c1e7191f9526bf54ed99389392c76d852f96 100644 (file)
--- a/src/openvpn/ssl.c
+++ b/src/openvpn/ssl.c
@@ -1872,11 +1872,6 @@ tls_session_update_crypto_params(struct tls_session *session,
     {
         msg(D_HANDSHAKE, "Data Channel: using negotiated cipher '%s'",
             options->ciphername);
-        if (options->keysize)
-        {
-            msg(D_HANDSHAKE, "NCP: overriding user-set keysize with default");
-            options->keysize = 0;
-        }
     }
     else
     {
@@ -1887,7 +1882,7 @@ tls_session_update_crypto_params(struct tls_session *session,
     }
 
     init_key_type(&session->opt->key_type, options->ciphername,
-                  options->authname, options->keysize, true, true);
+                  options->authname, true, true);
 
     bool packet_id_long_form = cipher_kt_mode_ofb_cfb(session->opt->key_type.cipher);
     session->opt->crypto_flags &= ~(CO_PACKET_ID_LONG_FORM);