Merge pull request #310 from whisperfish/keys-wf

Add `Keys` sync message

libsignal-service/src/account_manager.rs

@@ -18,6 +18,7 @@ use tracing_futures::Instrument;
 use zkgroup::profiles::ProfileKey;
 
 use crate::content::ContentBody;
+use crate::master_key::MasterKey;
 use crate::pre_keys::{
     KyberPreKeyEntity, PreKeyEntity, PreKeysStore, SignedPreKeyEntity,
     PRE_KEY_BATCH_SIZE, PRE_KEY_MINIMUM,
@@ -277,6 +278,7 @@ impl<Service: PushService> AccountManager<Service> {
         aci_identity_store: &dyn IdentityKeyStore,
         pni_identity_store: &dyn IdentityKeyStore,
         credentials: ServiceCredentials,
+        master_key: Option<MasterKey>,
     ) -> Result<(), ProvisioningError> {
         let query: HashMap<_, _> = url.query_pairs().collect();
         let ephemeral_id =
@@ -328,7 +330,7 @@ impl<Service: PushService> AccountManager<Service> {
             provisioning_code: Some(provisioning_code),
             read_receipts: None,
             user_agent: None,
-            master_key: None, // XXX
+            master_key: master_key.map(|x| x.into()),
         };
 
         let cipher = ProvisioningCipher::from_public(pub_key);

libsignal-service/src/lib.rs

@@ -14,6 +14,7 @@ pub mod content;
 mod digeststream;
 pub mod envelope;
 pub mod groups_v2;
+pub mod master_key;
 pub mod messagepipe;
 pub mod models;
 pub mod pre_keys;
@@ -79,6 +80,7 @@ pub mod prelude {
             AccessControl, Group, Member, PendingMember, RequestingMember,
             Timer,
         },
+        master_key::{MasterKey, MasterKeyStore, StorageServiceKey},
         proto::{
             attachment_pointer::AttachmentIdentifier, sync_message::Contacts,
             AttachmentPointer,

libsignal-service/src/master_key.rs

@@ -0,0 +1,111 @@
+const MASTER_KEY_LEN: usize = 32;
+const STORAGE_KEY_LEN: usize = 32;
+
+#[derive(Debug, PartialEq)]
+pub struct MasterKey {
+    pub inner: [u8; MASTER_KEY_LEN],
+}
+
+impl MasterKey {
+    pub fn generate() -> Self {
+        use rand::Rng;
+
+        // Create random bytes
+        let mut rng = rand::thread_rng();
+        let mut inner = [0_u8; MASTER_KEY_LEN];
+        rng.fill(&mut inner);
+        Self { inner }
+    }
+
+    pub fn from_slice(
+        slice: &[u8],
+    ) -> Result<Self, std::array::TryFromSliceError> {
+        let inner = slice.try_into()?;
+        Ok(Self { inner })
+    }
+}
+
+impl From<MasterKey> for Vec<u8> {
+    fn from(val: MasterKey) -> Self {
+        val.inner.to_vec()
+    }
+}
+
+#[derive(Debug, PartialEq)]
+pub struct StorageServiceKey {
+    pub inner: [u8; STORAGE_KEY_LEN],
+}
+
+impl StorageServiceKey {
+    pub fn from_master_key(master_key: &MasterKey) -> Self {
+        use hmac::{Hmac, Mac};
+        use sha2::Sha256;
+
+        type HmacSha256 = Hmac<Sha256>;
+        const KEY: &[u8] = b"Storage Service Encryption";
+
+        let mut mac = HmacSha256::new_from_slice(&master_key.inner).unwrap();
+        mac.update(KEY);
+        let result = mac.finalize();
+        let inner: [u8; STORAGE_KEY_LEN] = result.into_bytes().into();
+
+        Self { inner }
+    }
+
+    pub fn from_slice(
+        slice: &[u8],
+    ) -> Result<Self, std::array::TryFromSliceError> {
+        let inner = slice.try_into()?;
+        Ok(Self { inner })
+    }
+}
+
+impl From<StorageServiceKey> for Vec<u8> {
+    fn from(val: StorageServiceKey) -> Self {
+        val.inner.to_vec()
+    }
+}
+
+/// Storage trait for handling MasterKey and StorageKey.
+pub trait MasterKeyStore {
+    /// Fetch the master key from the store if it exists.
+    fn fetch_master_key(&self) -> Option<MasterKey>;
+
+    /// Fetch the storage service key from the store if it exists.
+    fn fetch_storage_service_key(&self) -> Option<StorageServiceKey>;
+
+    /// Save (or clear) the master key to the store.
+    fn store_master_key(&self, master_key: Option<&MasterKey>);
+
+    /// Save (or clear) the storage service key to the store.
+    fn store_storage_service_key(
+        &self,
+        storage_key: Option<&StorageServiceKey>,
+    );
+}
+
+mod tests {
+    #[test]
+    fn derive_storage_key_from_master_key() {
+        use super::{MasterKey, StorageServiceKey};
+        use base64::prelude::*;
+
+        // This test passed with actual 'masterKey' and 'storageKey' values taken
+        // from Signal Desktop v7.23.0 database at 2024-09-08 after linking it with Signal Andoid.
+
+        let master_key_bytes = BASE64_STANDARD
+            .decode("9hquLIIZmom8fHF7H8pbUAreawmPLEqli5ceJ94pFkU=")
+            .unwrap();
+        let storage_key_bytes = BASE64_STANDARD
+            .decode("QMgZ5RGTLFTr4u/J6nypaJX6DKDlSgMw8vmxU6gxnvI=")
+            .unwrap();
+        assert_eq!(master_key_bytes.len(), 32);
+        assert_eq!(storage_key_bytes.len(), 32);
+
+        let master_key = MasterKey::from_slice(&master_key_bytes).unwrap();
+        let storage_key = StorageServiceKey::from_master_key(&master_key);
+
+        assert_eq!(master_key.inner, master_key_bytes.as_slice());
+        assert_eq!(storage_key.inner, storage_key_bytes.as_slice());
+    }
+}

libsignal-service/src/sender.rs

@@ -752,6 +752,56 @@ where
         Ok(())
     }
 
+    /// Send `Keys` synchronization message
+    #[tracing::instrument(skip(self))]
+    pub async fn send_keys(
+        &mut self,
+        recipient: &ServiceAddress,
+        keys: sync_message::Keys,
+    ) -> Result<(), MessageSenderError> {
+        let msg = SyncMessage {
+            keys: Some(keys),
+            ..SyncMessage::with_padding()
+        };
+
+        let ts = Utc::now().timestamp_millis() as u64;
+        self.send_message(recipient, None, msg, ts, false, false)
+            .await?;
+
+        Ok(())
+    }
+
+    /// Send a `Keys` request message
+    #[tracing::instrument(skip(self))]
+    pub async fn send_sync_message_request(
+        &mut self,
+        recipient: &ServiceAddress,
+        request_type: sync_message::request::Type,
+    ) -> Result<(), MessageSenderError> {
+        if self.device_id == DEFAULT_DEVICE_ID.into() {
+            let reason = format!(
+                "Primary device can't send sync requests, ignoring {:?}",
+                request_type
+            );
+            return Err(MessageSenderError::ServiceError(
+                ServiceError::SendError { reason },
+            ));
+        }
+
+        let msg = SyncMessage {
+            request: Some(sync_message::Request {
+                r#type: Some(request_type.into()),
+            }),
+            ..SyncMessage::with_padding()
+        };
+
+        let ts = Utc::now().timestamp_millis() as u64;
+        self.send_message(recipient, None, msg, ts, false, false)
+            .await?;
+
+        Ok(())
+    }
+
     #[tracing::instrument(level = "trace", skip(self))]
     fn create_pni_signature(
         &mut self,