signature verification

client-network/src/cryptographic_signature.rs

@@ -1,4 +1,8 @@
+use std::io::Read;
+
 use crate::messages_structure::HandshakeMessage;
+use bytes::Bytes;
+use p256::EncodedPoint;
 use p256::ecdsa::{
     Signature, SigningKey, VerifyingKey,
     signature::{Signer, Verifier},
@@ -9,6 +13,7 @@ use sha2::{Digest, Sha256};
 ///
 /// contains the ecdsa private key, the ecdsa public key and the username
 ///
+///
 pub struct CryptographicSignature {
     priv_key: SigningKey,
     pub pub_key: VerifyingKey,
@@ -42,6 +47,53 @@ pub fn formatPubKey(crypto_pair: CryptographicSignature) -> String {
     hex::encode(pubkey_bytes)
 }
 
+pub async fn get_peer_key(username: &String) -> Result<VerifyingKey, reqwest::Error> {
+    let client = reqwest::Client::new();
+    let uri = format!("https://jch.irif.fr:8443/peers/{}/key", username);
+    let res = client.get(uri).send().await?;
+    if res.status().is_success() {
+        println!("Successfully retreived the peers key.");
+    } else {
+        eprintln!(
+            "Failed to get the peers key from the server. Status: {}",
+            res.status()
+        );
+    }
+    let body: Bytes = res.bytes().await?;
+    let slice: &[u8] = body.as_ref();
+    let body_bytes: &[u8; 64] = slice.try_into().expect("size error");
+    let received_key = convert_verifyingkey(body_bytes);
+    Ok(received_key)
+}
+
+fn convert_verifyingkey(raw_xy: &[u8; 64]) -> VerifyingKey {
+    let mut sec1 = [0u8; 65];
+    sec1[0] = 0x04;
+    sec1[1..].copy_from_slice(raw_xy);
+
+    let ep = EncodedPoint::from_bytes(&sec1).expect("invalid point bytes");
+    let pk = VerifyingKey::from_encoded_point(&ep).expect("invalid encoded point");
+    VerifyingKey::from(pk)
+}
+
+pub fn verify_signature(pubkey: VerifyingKey, message: &Vec<u8>) -> bool {
+    let length_bytes: [u8; 2] = message[5..7].try_into().expect("Taille incorrecte");
+    let length = u16::from_be_bytes(length_bytes);
+    println!("message length: {}", length);
+    let msg_to_hash = &message[..length as usize + 7];
+    let signature_bytes = &message[length as usize + 7..length as usize + 7 + 64];
+    println!("conversion start");
+    let sig = match Signature::from_bytes(signature_bytes.try_into().expect("conversion error")) {
+        Ok(s) => s,
+        Err(_) => return false,
+    };
+    println!("conversion done");
+    match pubkey.verify(&msg_to_hash, &sig) {
+        Ok(()) => true,
+        Err(_) => false,
+    }
+}
+
 ///
 /// takes a serialized message and adds the signature using the private key
 ///

client-network/src/lib.rs

@@ -104,7 +104,7 @@ pub fn start_p2p_executor(
 
                         let messages_list = HashMap::<i32, EventType>::new();
 
-                        let username = String::from("Gamixtreize");
+                        let username = String::from("az");
 
                         let crypto_pair = CryptographicSignature::new(username);
 

client-network/src/message_handling.rs

@@ -1,5 +1,7 @@
 use crate::{
-    cryptographic_signature::{CryptographicSignature, sign_message},
+    cryptographic_signature::{
+        CryptographicSignature, get_peer_key, sign_message, verify_signature,
+    },
     messages_channels::MultipleSenders,
     messages_structure::HandshakeMessage,
     registration,
@@ -69,6 +71,20 @@ pub fn handle_recevied_message(
         None => {
             let message_type = recevied_message[4];
             if message_type == 1 {
+                println!("verify the signature");
+                let parsed_received_message = HandshakeMessage::parse(recevied_message.to_vec());
+                let received_name = String::from_utf8(parsed_received_message.name).expect("error");
+                let peer_pubkey = tokio::runtime::Runtime::new()
+                    .unwrap()
+                    .block_on(get_peer_key(&received_name))
+                    .expect("failed to retrieve public key");
+
+                if !verify_signature(peer_pubkey, recevied_message) {
+                    println!(
+                        "incorrect signature from given peer: {}, ignoring message {}",
+                        &received_name, id
+                    );
+                } else {
                     let username_size = crypto_pair.username.len();
                     let hello_handshake = HandshakeMessage::helloReply(
                         id as u32,
@@ -89,6 +105,7 @@ pub fn handle_recevied_message(
                         }
                     }
                 }
+            }
             print!("Message not found for ID: {}", id)
         }
     }

client-network/src/messages_structure.rs

@@ -7,12 +7,12 @@ pub struct UDPMessage {
 }
 
 pub struct HandshakeMessage {
-    id: u32,
+    pub id: u32,
     msg_type: u8,
     length: u16,
     extensions: u32,
-    name: Vec<u8>,
+    pub name: Vec<u8>,
-    signature: Vec<u8>,
+    pub signature: Vec<u8>,
 }
 
 impl UDPMessage {
@@ -130,9 +130,9 @@ impl HandshakeMessage {
         let extensions_bytes: [u8; 4] = received_message[7..11]
             .try_into()
             .expect("Taille incorrecte");
-        let name_bytes = &received_message[11..12 + msg_length as usize];
+        let name_bytes = &received_message[11..(11 + msg_length - 4) as usize];
         let signature_bytes =
-            &received_message[12 + msg_length as usize..(13 + msg_length + 32) as usize];
+            &received_message[(11 + msg_length - 4) as usize..(11 + msg_length - 4 + 64) as usize];
         HandshakeMessage {
             id: u32::from_be_bytes(id_bytes),
             msg_type: received_message[4],

client-network/src/registration.rs

@@ -48,7 +48,7 @@ pub async fn get_socket_address(username: String) -> Result<Bytes, reqwest::Erro
         println!("Successfully retreived the addresses.");
     } else {
         eprintln!(
-            "Failed to register with the server. Status: {}",
+            "Failed to get the peers addresses from the server. Status: {}",
             res.status()
         );
     }