Decouple stream bypass from TLS encrypted bypass v5

doc/userguide/configuration/suricata-yaml.rst

@@ -1736,21 +1736,26 @@ Encrypted traffic
 
 There is no decryption of encrypted traffic, so once the handshake is complete
 continued tracking of the session is of limited use. The ``encryption-handling``
-option controls the behavior after the handshake.
+option in ``app-layer.protocols.tls`` and ``app-layer.protocols.ssh`` controls
+the behavior after the handshake.
 
-If ``encryption-handling`` is set to ``default`` (or if the option is not set),
-Suricata will continue to track the SSL/TLS session. Inspection will be limited,
-as raw ``content`` inspection will still be disabled. There is no point in doing
-pattern matching on traffic known to be encrypted. Inspection for (encrypted)
-Heartbleed and other protocol anomalies still happens.
+If ``encryption-handling`` in TLS protocol is set to ``default``
+(or if the option is not set), Suricata will continue to track the SSL/TLS
+session. Inspection will be limited, as raw ``content`` inspection will still
+be disabled. There is no point in doing pattern matching on traffic known to
+be encrypted. Inspection for (encrypted) Heartbleed and other protocol
+anomalies still happens.
 
-When ``encryption-handling`` is set to ``bypass``, all processing of this session is
-stopped. No further parsing and inspection happens. If ``stream.bypass`` is enabled
-this will lead to the flow being bypassed, either inside Suricata or by the
-capture method if it supports it and is configured for it.
+.. note:: The ``encryption-handling: default`` option is only available for
+          SSL/TLS and not for SSH protocol.
 
-Finally, if ``encryption-handling`` is set to ``full``, Suricata will process the
-flow as normal, without inspection limitations or bypass.
+When ``encryption-handling`` is set to ``bypass``, all processing of this
+session is stopped. No further parsing and inspection happens. This will also
+lead to the flow being bypassed, either inside Suricata or by the capture method
+if it supports it and is configured for it.
+
+Finally, if ``encryption-handling`` is set to ``full``, Suricata will process
+the flow as normal, without inspection limitations or bypass.
 
 The option has replaced the ``no-reassemble`` option. If ``no-reassemble`` is
 present, and ``encryption-handling`` is not, ``false`` is interpreted as
@@ -2078,12 +2083,12 @@ are typically provided through the command line, are contained in the node
 parameters. There are two ways to specify arguments: lengthy and short.
 Dashes are omitted when describing the arguments. This setup node can be
 used to set up the memory configuration, accessible NICs, and other EAL-related
-parameters, among other things. The node `dpdk.eal-params` also supports 
-multiple arguments of the same type. This can be useful for EAL arguments 
-such as `--vdev`, `--allow`, or `--block`. Values for these EAL arguments 
-are specified as a comma-separated list. 
-An example of such usage can be found in the example above where the `allow` 
-argument only makes `0000:3b:00.0` and `0000:3b:00.1` accessible to Suricata. 
+parameters, among other things. The node `dpdk.eal-params` also supports
+multiple arguments of the same type. This can be useful for EAL arguments
+such as `--vdev`, `--allow`, or `--block`. Values for these EAL arguments
+are specified as a comma-separated list.
+An example of such usage can be found in the example above where the `allow`
+argument only makes `0000:3b:00.0` and `0000:3b:00.1` accessible to Suricata.
 arguments with list node. such as --vdev, --allow, --block eal options.
 The definition of lcore affinity as an EAL
 parameter is a standard practice. However, lcore parameters like `-l`, `-c`,

doc/userguide/performance/ignoring-traffic.rst

@@ -73,10 +73,14 @@ Example::
 encrypted traffic
 -----------------
 
-The TLS app layer parser has the ability to stop processing encrypted traffic
-after the initial handshake. By setting the `app-layer.protocols.tls.encryption-handling`
-option to `bypass` the rest of this flow is ignored. If flow bypass is enabled,
-the bypass is done in the kernel or in hardware.
+The TLS and SSH app layer parsers have the ability to stop processing
+encrypted traffic after the initial handshake. By setting the
+`app-layer.protocols.tls.encryption-handling` and
+`app-layer.protocols.ssh.encryption-handling` options to `bypass` Suricata
+bypasses flows once the handshake is completed and encrypted traffic is
+detected. The rest of these flow is ignored.
+The bypass is done in the kernel or in hardware, similar to how flow bypass
+is done.
 
 .. _bypass:
 

doc/userguide/upgrade.rst

@@ -77,6 +77,17 @@ Major changes
     - sip.to
     - sip.content_type
     - sip.content_length
+- Encrypted traffic bypass has been decoupled from stream.bypass setting.
+  This means that encrypted traffic can be bypassed while tracking/fully
+  inspecting other traffic as well.
+- Encrypted SSH traffic bypass is now independently controlled through
+  `app-layer.protocols.ssh.encryption-handling` setting. The setting can either
+  be `bypass` or `full`, setting `default` as found in the TLS protocol is
+  NOT supported. To retain the previous behavior of encrypted traffic bypass
+  combined with stream depth bypass, set
+  `app-layer.protocols.ssh.encryption-handling` to `bypass` (while also
+  setting `app-layer.protocols.tls.encryption-handling` to `bypass` and
+  `stream.bypass` to `true`).
 
 Removals
 ~~~~~~~~

rust/src/ssh/ssh.rs

@@ -25,11 +25,16 @@ use crate::frames::Frame;
 
 static mut ALPROTO_SSH: AppProto = ALPROTO_UNKNOWN;
 static HASSH_ENABLED: AtomicBool = AtomicBool::new(false);
+static BYPASS_ENABLED: AtomicBool = AtomicBool::new(false);
 
 fn hassh_is_enabled() -> bool {
     HASSH_ENABLED.load(Ordering::Relaxed)
 }
 
+fn enc_bypass_is_enabled() -> bool {
+    BYPASS_ENABLED.load(Ordering::Relaxed)
+}
+
 #[derive(AppLayerFrameType)]
 pub enum SshFrameType {
     RecordHdr,
@@ -197,11 +202,18 @@ impl SSHState {
                                 unsafe {
                                     AppLayerParserStateSetFlag(
                                         pstate,
-                                        APP_LAYER_PARSER_NO_INSPECTION
-                                        | APP_LAYER_PARSER_NO_REASSEMBLY
-                                        | APP_LAYER_PARSER_BYPASS_READY,
+                                        APP_LAYER_PARSER_NO_INSPECTION,
                                     );
                                 }
+                                if enc_bypass_is_enabled() {
+                                    unsafe {
+                                        AppLayerParserStateSetFlag(
+                                            pstate,
+                                            APP_LAYER_PARSER_NO_REASSEMBLY
+                                            | APP_LAYER_PARSER_BYPASS_READY,
+                                        );
+                                    }
+                                }
                             }
                         }
                         _ => {}
@@ -549,6 +561,16 @@ pub extern "C" fn rs_ssh_hassh_is_enabled() -> bool {
     hassh_is_enabled()
 }
 
+#[no_mangle]
+pub extern "C" fn rs_ssh_enable_bypass() {
+    BYPASS_ENABLED.store(true, Ordering::Relaxed)
+}
+
+#[no_mangle]
+pub extern "C" fn rs_ssh_enc_bypass_is_enabled() -> bool {
+    enc_bypass_is_enabled()
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn rs_ssh_tx_get_log_condition( tx: *mut std::os::raw::c_void) -> bool {
     let tx = cast_pointer!(tx, SSHTransaction);

src/app-layer-ssh.c

@@ -55,6 +55,8 @@
 
 /* HASSH fingerprints are disabled by default */
 #define SSH_CONFIG_DEFAULT_HASSH false
+/* Bypassing the encrypted part of the connections */
+#define SSH_CONFIG_DEFAULT_BYPASS true
 
 static int SSHRegisterPatternsForProtocolDetection(void)
 {
@@ -103,6 +105,23 @@ void RegisterSSHParsers(void)
         if (RunmodeIsUnittests() || enable_hassh) {
             rs_ssh_enable_hassh();
         }
+
+        bool enc_bypass = SSH_CONFIG_DEFAULT_BYPASS;
+        ConfNode *enc_handle = ConfGetNode("app-layer.protocols.ssh.encryption-handling");
+        if (enc_handle != NULL && enc_handle->val != NULL) {
+            if (strcmp(enc_handle->val, "full") == 0) {
+                enc_bypass = false;
+            } else if (strcmp(enc_handle->val, "bypass") == 0) {
+                enc_bypass = true;
+            } else {
+                enc_bypass = SSH_CONFIG_DEFAULT_BYPASS;
+            }
+        }
+
+        if (enc_bypass) {
+            SCLogConfig("ssh: bypass on the start of encryption enabled");
+            rs_ssh_enable_bypass();
+        }
     }
 
     SCLogDebug("Registering Rust SSH parser.");

src/stream-tcp.c

@@ -5659,17 +5659,13 @@ int StreamTcpPacket (ThreadVars *tv, Packet *p, StreamTcpThread *stt,
         }
 
         if (ssn->flags & STREAMTCP_FLAG_BYPASS) {
-            /* we can call bypass callback, if enabled */
-            if (StreamTcpBypassEnabled()) {
-                PacketBypassCallback(p);
-            }
-
-        /* if stream is dead and we have no detect engine at all, bypass. */
+            PacketBypassCallback(p);
         } else if (g_detect_disabled &&
                 (ssn->client.flags & STREAMTCP_STREAM_FLAG_NOREASSEMBLY) &&
                 (ssn->server.flags & STREAMTCP_STREAM_FLAG_NOREASSEMBLY) &&
                 StreamTcpBypassEnabled())
         {
+            /* if stream is dead and we have no detect engine at all, bypass. */
             SCLogDebug("bypass as stream is dead and we have no rules");
             PacketBypassCallback(p);
         }

suricata.yaml.in

@@ -931,7 +931,14 @@ app-layer:
       #enabled: yes
     ssh:
       enabled: yes
-      #hassh: yes
+      # hassh: no
+
+      # What to do when the encrypted communications start:
+      # - bypass:  stop processing this flow as much as possible.
+      #            Offload flow bypass to kernel or hardware if possible.
+      # - full:    keep tracking and inspection as normal
+      #
+      # encryption-handling: full
     doh2:
       enabled: yes
     http2: