2 files changed, 46 insertions, 5 deletions

diff --git a/client-web/source/protocol/crypto.ts b/client-web/source/protocol/crypto.ts
index 654e80b..76f48c0 100644
--- a/client-web/source/protocol/crypto.ts
+++ b/client-web/source/protocol/crypto.ts
@@ -73,6 +73,40 @@ export async function crypt_decrypt(key: CryptoKey, data: string): Promise<strin
     }
 }
 
+//* Code that might be useful in the future for signing
+// const ECDSA_PARAMS = { name: "ECDSA", namedCurve: "P-521", hash: { name: "SHA-384" } }
+// export async function crypto_sign(key: CryptoKey, message: string): Promise<string> {
+//     const signature = await crypto.subtle.sign(
+//         ECDSA_PARAMS,
+//         key,
+//         new TextEncoder().encode(message)
+//     )
+//     return buf_to_base64(new Uint8Array(signature))
+// }
+// export async function crypto_generate_signing_key(): Promise<CryptoKeyPair> {
+//     return await crypto.subtle.generateKey(
+//         ECDSA_PARAMS,
+//         false,
+//         ["sign", "verify"]
+//     )
+// }
+// export async function crypto_verify(key: CryptoKey, message: string, signature: string): Promise<boolean> {
+//     return await crypto.subtle.verify(
+//         ECDSA_PARAMS,
+//         key,
+//         base64_to_buf(signature).buffer,
+//         new TextEncoder().encode(message)
+//     )
+// }
+// export async function export_public_signing_key(key: CryptoKey): Promise<string> {
+//     const buf = await crypto.subtle.exportKey("spki", key)
+//     return buf_to_base64(new Uint8Array(buf))
+// }
+// export async function import_public_signing_key(der: string): Promise<CryptoKey | undefined> {
+//     const bin_der = base64_to_buf(der).buffer; // TODO safety
+//     return await crypto.subtle.importKey("spki", bin_der, ECDSA_PARAMS, true, ["verify"]) // TODO safety
+// }
+
 export function base64_to_buf(data: string): Uint8Array {
     const binary_string = globalThis.atob(data);
     const bytes = new Uint8Array(binary_string.length);
diff --git a/client-web/source/protocol/mod.ts b/client-web/source/protocol/mod.ts
index b225ced..c756742 100644
--- a/client-web/source/protocol/mod.ts
+++ b/client-web/source/protocol/mod.ts
@@ -1,4 +1,4 @@
-import { ClientboundPacket, RelayMessage, ServerboundPacket } from "../../../common/packets.d.ts"
+import { ClientboundPacket, RelayMessage, RelayMessageWrapper, ServerboundPacket } from "../../../common/packets.d.ts"
 import { log } from "../logger.ts"
 import { crypto_encrypt, crypto_seeded_key, crypt_decrypt, crypt_hash } from "./crypto.ts"
 
@@ -7,6 +7,7 @@ export class SignalingConnection {
     websocket!: WebSocket
     signaling_id!: string
     key!: CryptoKey
+    my_id?: number // needed for outgoing relay messages
 
     control_handler: (_packet: ClientboundPacket) => void = () => { }
     relay_handler: (_sender: number, _message: RelayMessage) => void = () => { }
@@ -47,10 +48,15 @@ export class SignalingConnection {
     async on_message(data: string) {
         const packet: ClientboundPacket = JSON.parse(data) // TODO dont crash if invalid
         this.control_handler(packet)
+        if (packet.init) this.my_id = packet.init.your_id;
         if (packet.message) {
-            const inner_json = await crypt_decrypt(this.key, packet.message.message)
-            const inner: RelayMessage = JSON.parse(inner_json) // TODO make sure that protocol spec is met
-            this.relay_handler(packet.message.sender, inner)
+            const plain_json = await crypt_decrypt(this.key, packet.message.message)
+            const plain: RelayMessageWrapper = JSON.parse(plain_json) // TODO make sure that protocol spec is met
+            if (plain.sender == packet.message.sender)
+                this.relay_handler(packet.message.sender, plain.inner)
+            else {
+                log({ scope: "crypto", warn: true }, `message dropped: sender inconsistent (${plain.sender} != ${packet.message.sender})`)
+            }
         }
     }
 
@@ -59,7 +65,8 @@ export class SignalingConnection {
     }
     async send_relay(data: RelayMessage, recipient?: number | null) {
         recipient ??= undefined // null -> undefined
-        const message = await crypto_encrypt(this.key, JSON.stringify(data))
+        const packet: RelayMessageWrapper = { inner: data, sender: this.my_id! }
+        const message = await crypto_encrypt(this.key, JSON.stringify(packet))
         this.send_control({ relay: { recipient, message } })
     }
 }