c8bcc5c974
The CallOffer only advertised GOOD/DEGRADED/CATASTROPHIC. When a client uses a studio profile, the relay's choose_profile couldn't pick it. Now advertises all 6 profiles (studio 64k/48k/32k + good + degraded + catastrophic) in both Android engine and shared handshake. Also: the relay MUST be rebuilt with the new CodecId variants, otherwise it will fail to deserialize CallOffer messages containing studio QualityProfiles in supported_profiles. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
108 lines
3.6 KiB
Rust
108 lines
3.6 KiB
Rust
//! Client-side cryptographic handshake.
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//!
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//! Performs the caller role of the WarzonePhone key exchange:
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//! send `CallOffer` → recv `CallAnswer` → derive shared `CryptoSession`.
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use wzp_crypto::{CryptoSession, KeyExchange, WarzoneKeyExchange};
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use wzp_proto::{MediaTransport, QualityProfile, SignalMessage};
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/// Perform the client (caller) side of the cryptographic handshake.
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///
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/// 1. Derive identity from `seed`
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/// 2. Generate ephemeral X25519 keypair
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/// 3. Sign `(ephemeral_pub || "call-offer")` with identity key
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/// 4. Send `CallOffer` with identity_pub, ephemeral_pub, signature
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/// 5. Receive `CallAnswer`, verify callee signature
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/// 6. Derive shared ChaCha20-Poly1305 session
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pub async fn perform_handshake(
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transport: &dyn MediaTransport,
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seed: &[u8; 32],
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alias: Option<&str>,
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) -> Result<Box<dyn CryptoSession>, anyhow::Error> {
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// 1. Create key exchange from identity seed
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let mut kx = WarzoneKeyExchange::from_identity_seed(seed);
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let identity_pub = kx.identity_public_key();
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// 2. Generate ephemeral key
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let ephemeral_pub = kx.generate_ephemeral();
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// 3. Sign (ephemeral_pub || "call-offer")
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let mut sign_data = Vec::with_capacity(32 + 10);
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sign_data.extend_from_slice(&ephemeral_pub);
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sign_data.extend_from_slice(b"call-offer");
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let signature = kx.sign(&sign_data);
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// 4. Send CallOffer
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let offer = SignalMessage::CallOffer {
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identity_pub,
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ephemeral_pub,
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signature,
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supported_profiles: vec![
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QualityProfile::STUDIO_64K,
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QualityProfile::STUDIO_48K,
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QualityProfile::STUDIO_32K,
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QualityProfile::GOOD,
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QualityProfile::DEGRADED,
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QualityProfile::CATASTROPHIC,
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],
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alias: alias.map(|s| s.to_string()),
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};
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transport.send_signal(&offer).await?;
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// 5. Wait for CallAnswer
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let answer = transport
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.recv_signal()
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.await?
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.ok_or_else(|| anyhow::anyhow!("connection closed before receiving CallAnswer"))?;
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let (callee_identity_pub, callee_ephemeral_pub, callee_signature, _chosen_profile) = match answer
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{
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SignalMessage::CallAnswer {
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identity_pub,
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ephemeral_pub,
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signature,
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chosen_profile,
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} => (identity_pub, ephemeral_pub, signature, chosen_profile),
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other => {
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return Err(anyhow::anyhow!(
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"expected CallAnswer, got {:?}",
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std::mem::discriminant(&other)
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))
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}
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};
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// 6. Verify callee's signature over (ephemeral_pub || "call-answer")
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let mut verify_data = Vec::with_capacity(32 + 11);
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verify_data.extend_from_slice(&callee_ephemeral_pub);
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verify_data.extend_from_slice(b"call-answer");
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if !WarzoneKeyExchange::verify(&callee_identity_pub, &verify_data, &callee_signature) {
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return Err(anyhow::anyhow!("callee signature verification failed"));
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}
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// 7. Derive session
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let session = kx.derive_session(&callee_ephemeral_pub)?;
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Ok(session)
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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// Integration test lives in tests/ — unit-level coverage relies on wzp-crypto tests.
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#[test]
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fn sign_data_format() {
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let kx = WarzoneKeyExchange::from_identity_seed(&[0xAA; 32]);
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let eph = [0x11u8; 32];
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let mut data = Vec::new();
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data.extend_from_slice(&eph);
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data.extend_from_slice(b"call-offer");
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let sig = kx.sign(&data);
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assert!(WarzoneKeyExchange::verify(
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&kx.identity_public_key(),
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&data,
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&sig,
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));
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}
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}
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