fixed #961 - added option to allow insecure ssh kex (#971)

warpgate-common/src/config/target.rs

@@ -15,6 +15,8 @@ pub struct TargetSSHOptions {
     #[serde(default = "_default_username")]
     pub username: String,
     #[serde(default)]
+    pub allow_insecure_algos: Option<bool>,
+    #[serde(default)]
     pub auth: SSHTargetAuth,
 }
 

warpgate-protocol-ssh/src/client/mod.rs

@@ -15,8 +15,8 @@ pub use error::SshClientError;
 use futures::pin_mut;
 use handler::ClientHandler;
 use russh::client::Handle;
-use russh::{Preferred, Sig};
-use russh_keys::key::{self, PublicKey};
+use russh::{kex, Preferred, Sig};
+use russh_keys::key::PublicKey;
 use tokio::sync::mpsc::{unbounded_channel, UnboundedReceiver, UnboundedSender};
 use tokio::sync::{oneshot, Mutex};
 use tokio::task::JoinHandle;
@@ -401,16 +401,28 @@ impl RemoteClient {
         };
 
         info!(?address, username = &ssh_options.username[..], "Connecting");
-        let config = russh::client::Config {
-            preferred: Preferred {
-                key: &[
-                    key::ED25519,
-                    key::RSA_SHA2_256,
-                    key::RSA_SHA2_512,
-                    key::SSH_RSA,
+        let algos = if ssh_options.allow_insecure_algos.unwrap_or(false) {
+            Preferred {
+                kex: &[
+                    kex::CURVE25519,
+                    kex::CURVE25519_PRE_RFC_8731,
+                    kex::DH_G16_SHA512,
+                    kex::DH_G14_SHA256, // non-default
+                    kex::DH_G14_SHA256,
+                    kex::DH_G1_SHA1, // non-default
+                    kex::EXTENSION_SUPPORT_AS_CLIENT,
+                    kex::EXTENSION_SUPPORT_AS_SERVER,
+                    kex::EXTENSION_OPENSSH_STRICT_KEX_AS_CLIENT,
+                    kex::EXTENSION_OPENSSH_STRICT_KEX_AS_SERVER,
                 ],
                 ..<_>::default()
-            },
+            }
+        } else {
+            Preferred::default()
+        };
+
+        let config = russh::client::Config {
+            preferred: algos,
             ..Default::default()
         };
         let config = Arc::new(config);

warpgate-web/src/admin/CreateTarget.svelte

@@ -15,24 +15,24 @@ async function create () {
     try {
         const options: TargetOptions|undefined = {
             Ssh: {
-                kind: 'Ssh',
+                kind: 'Ssh' as const,
                 host: '192.168.0.1',
                 port: 22,
                 username: 'root',
                 auth: {
-                    kind: 'PublicKey',
+                    kind: 'PublicKey' as const,
                 },
-            } as TargetOptions,
+            },
             Http: {
-                kind: 'Http',
+                kind: 'Http' as const,
                 url: 'http://192.168.0.1',
                 tls: {
                     mode: TlsMode.Preferred,
                     verify: true,
                 },
-            } as TargetOptions,
+            },
             MySql: {
-                kind: 'MySql',
+                kind: 'MySql' as const,
                 host: '192.168.0.1',
                 port: 3306,
                 tls: {
@@ -41,7 +41,7 @@ async function create () {
                 },
                 username: 'root',
                 password: '',
-            } as TargetOptions,
+            },
         }[type]
         if (!options) {
             return

warpgate-web/src/admin/Target.svelte

@@ -175,6 +175,15 @@ async function toggleRole (role: Role) {
                 </FormGroup>
             {/if}
         </div>
+
+        <div class="d-flex">
+            <Input
+                class="mb-0 me-2"
+                type="switch"
+                label="Allow insecure SSH algorithms (e.g. for older networks devices)"
+                checked={target.options.allowInsecureAlgos} />
+        </div>
+
     {/if}
 
     {#if target.options.kind === 'Http'}

warpgate-web/src/admin/lib/openapi-schema.json

@@ -1657,6 +1657,9 @@
           "username": {
             "type": "string"
           },
+          "allow_insecure_algos": {
+            "type": "boolean"
+          },
           "auth": {
             "$ref": "#/components/schemas/SSHTargetAuth"
           }