Rename aead-tag-at-end to aead-epoch

Since we introduce aead at the end and epoch data keys together and only allow the aead tag at the end if epoch data keys are used, we can use just one flag for both of them Change-Id: I9e9433b56dcbaa538d9bed30e50cf74948c647cc Signed-off-by: Arne Schwabe <[email protected]> Acked-by: MaxF <[email protected]> Message-Id: <[email protected]> URL: https://www.mail-archive.com/[email protected]/msg30395.html Signed-off-by: Gert Doering <[email protected]>
OpenVPN · Jan 10, 2025 · 0671a4d · 0671a4d
1 parent 92adbc8
commit 0671a4d
Show file tree

Hide file tree

Showing 8 changed files with 19 additions and 13 deletions.
diff --git a/doc/man-sections/client-options.rst b/doc/man-sections/client-options.rst
@@ -367,6 +367,7 @@ configuration.
     - bit 7: The client is capable of sending exit notification via control channel using ``EXIT`` message. Also, the client is accepting the protocol-flags pushed option for the EKM capability
     - bit 8: The client is capable of accepting ``AUTH_FAILED,TEMP`` messages
     - bit 9: The client is capable of dynamic tls-crypt
+    - bit 10: The client is capable of data epoch keys
 
   :code:`IV_NCP=2`
         Negotiable ciphers, client supports ``--cipher`` pushed by

diff --git a/src/openvpn/crypto.c b/src/openvpn/crypto.c
@@ -127,7 +127,7 @@ openvpn_encrypt_aead(struct buffer *buf, struct buffer work,
     dmsg(D_PACKET_CONTENT, "ENCRYPT AD: %s",
          format_hex(BPTR(&work), BLEN(&work), 0, &gc));
 
-    if (!(opt->flags & CO_AEAD_TAG_AT_THE_END))
+    if (!(opt->flags & CO_EPOCH_DATA_KEY_FORMAT))
     {
         /* Reserve space for authentication tag */
         mac_out = buf_write_alloc(&work, mac_len);
@@ -148,7 +148,7 @@ openvpn_encrypt_aead(struct buffer *buf, struct buffer work,
     ASSERT(buf_inc_len(&work, outlen));
 
     /* if the tag is at end the end, allocate it now */
-    if (opt->flags & CO_AEAD_TAG_AT_THE_END)
+    if (opt->flags & CO_EPOCH_DATA_KEY_FORMAT)
     {
         /* Reserve space for authentication tag */
         mac_out = buf_write_alloc(&work, mac_len);
@@ -479,7 +479,7 @@ openvpn_decrypt_aead(struct buffer *buf, struct buffer work,
     uint8_t *tag_ptr = NULL;
     int data_len = 0;
 
-    if (opt->flags & CO_AEAD_TAG_AT_THE_END)
+    if (opt->flags & CO_EPOCH_DATA_KEY_FORMAT)
     {
         data_len = BLEN(buf) - tag_size;
         tag_ptr = BPTR(buf) + data_len;

diff --git a/src/openvpn/crypto.h b/src/openvpn/crypto.h
@@ -373,9 +373,11 @@ struct crypto_options
     /**< Bit-flag indicating that renegotiations are using tls-crypt
      *   with a TLS-EKM derived key.
      */
-#define CO_AEAD_TAG_AT_THE_END  (1<<8)
-    /**< Bit-flag indicating that the AEAD tag is at the end of the
-     *   packet.
+#define CO_EPOCH_DATA_KEY_FORMAT  (1<<8)
+    /**< Bit-flag indicating the epoch the data format. This format
+     * has the AEAD tag at the end of the packet and is using a longer
+     * 64-bit packet id that is split into a 16 bit epoch and 48 bit
+     * epoch counter
      */
 
     unsigned int flags;         /**< Bit-flags determining behavior of

diff --git a/src/openvpn/init.c b/src/openvpn/init.c
@@ -2407,9 +2407,9 @@ tls_print_deferred_options_results(struct context *c)
         {
             buf_printf(&out, " dyn-tls-crypt");
         }
-        if (o->imported_protocol_flags & CO_AEAD_TAG_AT_THE_END)
+        if (o->imported_protocol_flags & CO_EPOCH_DATA_KEY_FORMAT)
         {
-            buf_printf(&out, " aead-tag-end");
+            buf_printf(&out, " aead-epoch");
         }
     }
 

diff --git a/src/openvpn/options.c b/src/openvpn/options.c
@@ -8659,9 +8659,9 @@ add_option(struct options *options,
                 options->imported_protocol_flags |= CO_USE_DYNAMIC_TLS_CRYPT;
             }
 #endif
-            else if (streq(p[j], "aead-tag-end"))
+            else if (streq(p[j], "aead-epoch"))
             {
-                options->imported_protocol_flags |= CO_AEAD_TAG_AT_THE_END;
+                options->imported_protocol_flags |= CO_EPOCH_DATA_KEY_FORMAT;
             }
             else
             {

diff --git a/src/openvpn/push.c b/src/openvpn/push.c
@@ -689,9 +689,9 @@ prepare_push_reply(struct context *c, struct gc_arena *gc,
         buf_printf(&proto_flags, " dyn-tls-crypt");
     }
 
-    if (o->imported_protocol_flags & CO_AEAD_TAG_AT_THE_END)
+    if (o->imported_protocol_flags & CO_EPOCH_DATA_KEY_FORMAT)
     {
-        buf_printf(&proto_flags, " aead-tag-end");
+        buf_printf(&proto_flags, " aead-epoch");
     }
 
     if (buf_len(&proto_flags) > 0)

diff --git a/src/openvpn/ssl.h b/src/openvpn/ssl.h
@@ -108,6 +108,9 @@
 /** Support to dynamic tls-crypt (renegotiation with TLS-EKM derived tls-crypt key) */
 #define IV_PROTO_DYN_TLS_CRYPT   (1<<9)
 
+/** Support the extended packet id and epoch format for data channel packets */
+#define IV_PROTO_DATA_EPOCH      (1<<10)
+
 /** Supports the --dns option after all the incompatible changes */
 #define IV_PROTO_DNS_OPTION_V2   (1<<11)
 

diff --git a/tests/unit_tests/openvpn/test_ssl.c b/tests/unit_tests/openvpn/test_ssl.c
@@ -404,7 +404,7 @@ static void
 run_data_channel_with_cipher_end(const char *cipher)
 {
     struct crypto_options co = init_crypto_options(cipher, "none");
-    co.flags |= CO_AEAD_TAG_AT_THE_END;
+    co.flags |= CO_EPOCH_DATA_KEY_FORMAT;
     do_data_channel_round_trip(&co);
     uninit_crypto_options(&co);
 }