Add support for pushing secrets and receiving secret pushes

crates/matrix-sdk-crypto/CHANGELOG.md

@@ -49,6 +49,10 @@ All notable changes to this project will be documented in this file.
   been eliminated entirely.
   ([#5963](https://github.com/matrix-org/matrix-rust-sdk/pull/5963))
 
+- [**breaking**] `CryptoStore::get_secrets_from_inbox` now returns a `Vec` of
+  the secrets as strings, rather than a `Vec` of `GossippedSecret` structs.
+  ([#6164](https://github.com/matrix-org/matrix-rust-sdk/pull/6164))
+
 ## [0.16.0] - 2025-12-04
 
 ### Features

crates/matrix-sdk-crypto/src/gossiping/machine.rs

@@ -917,7 +917,7 @@ impl GossipMachine {
             // So we put the secret into our inbox. Later users can inspect the contents of
             // the inbox and decide if they want to activate the backup.
             info!("Received a backup decryption key, storing it into the secret inbox.");
-            changes.secrets.push(secret);
+            changes.secrets.push(secret.into());
         }
 
         Ok(())

crates/matrix-sdk-crypto/src/store/crypto_store_wrapper.rs

@@ -13,10 +13,13 @@ use super::{
     types::RoomKeyBundleInfo,
 };
 use crate::{
-    CryptoStoreError, GossippedSecret, OwnUserIdentityData, Session, UserIdentityData,
+    CryptoStoreError, OwnUserIdentityData, Session, UserIdentityData,
     olm::InboundGroupSession,
     store,
-    store::{Changes, DynCryptoStore, IntoCryptoStore, RoomKeyInfo, RoomKeyWithheldInfo},
+    store::{
+        Changes, DynCryptoStore, IntoCryptoStore, RoomKeyInfo, RoomKeyWithheldInfo,
+        types::SecretsInboxItem,
+    },
 };
 
 /// A wrapper for crypto store implementations that adds update notifiers.
@@ -43,7 +46,7 @@ pub(crate) struct CryptoStoreWrapper {
 
     /// The sender side of a broadcast channel which sends out secrets we
     /// received as a `m.secret.send` event.
-    secrets_broadcaster: broadcast::Sender<GossippedSecret>,
+    secrets_broadcaster: broadcast::Sender<SecretsInboxItem>,
 
     /// The sender side of a broadcast channel which sends out devices and user
     /// identities which got updated or newly created.
@@ -340,7 +343,7 @@ impl CryptoStoreWrapper {
 
     /// Receive notifications of gossipped secrets being received and stored in
     /// the secret inbox as a [`Stream`].
-    pub fn secrets_stream(&self) -> impl Stream<Item = GossippedSecret> + use<> {
+    pub fn secrets_stream(&self) -> impl Stream<Item = SecretsInboxItem> + use<> {
         let stream = BroadcastStream::new(self.secrets_broadcaster.subscribe());
         Self::filter_errors_out_of_stream(stream, "secrets_stream")
     }

crates/matrix-sdk-crypto/src/store/integration_tests.rs

@@ -34,6 +34,7 @@ macro_rules! cryptostore_integration_tests {
     () => {
         mod cryptostore_integration_tests {
             use std::collections::{BTreeMap, HashMap, HashSet};
+            use std::ops::Deref;
             use std::time::Duration;
 
             use assert_matches::assert_matches;
@@ -1104,23 +1105,25 @@ macro_rules! cryptostore_integration_tests {
                 );
 
                 let mut changes = Changes::default();
-                changes.secrets.push(value);
+                changes.secrets.push(value.into());
                 store.save_changes(changes).await.unwrap();
 
                 let restored = store.get_secrets_from_inbox(&SecretName::RecoveryKey).await.unwrap();
                 let first_secret = restored.first().expect("We should have restored a secret now");
-                assert_eq!(first_secret.event.content.secret, secret);
+                assert_eq!(first_secret.deref(), secret);
                 assert_eq!(restored.len(), 1, "We should only have one secret stored for now");
 
+                let secret2 = "It is another secret to everybody";
                 event.content.request_id = TransactionId::new();
+                event.content.secret = secret2.to_string();
                 let another_secret = GossippedSecret {
                     secret_name: SecretName::RecoveryKey,
                     gossip_request,
                     event,
                 };
 
                 let mut changes = Changes::default();
-                changes.secrets.push(another_secret);
+                changes.secrets.push(another_secret.into());
                 store.save_changes(changes).await.unwrap();
 
                 let restored = store.get_secrets_from_inbox(&SecretName::RecoveryKey).await.unwrap();

crates/matrix-sdk-crypto/src/store/memorystore.rs

@@ -1,4 +1,4 @@
-// Copyright 2020 The Matrix.org Foundation C.I.C.
+// Copyright 2020, 2026 The Matrix.org Foundation C.I.C.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -33,6 +33,7 @@ use ruma::{
 use tokio::sync::{Mutex, RwLock};
 use tracing::warn;
 use vodozemac::Curve25519PublicKey;
+use zeroize::Zeroizing;
 
 use super::{
     Account, CryptoStore, InboundGroupSession, Session,
@@ -43,7 +44,7 @@ use super::{
     },
 };
 use crate::{
-    gossiping::{GossipRequest, GossippedSecret, SecretInfo},
+    gossiping::{GossipRequest, SecretInfo},
     identities::{DeviceData, UserIdentityData},
     olm::{
         OutboundGroupSession, PickledAccount, PickledInboundGroupSession, PickledSession,
@@ -104,7 +105,7 @@ pub struct MemoryStore {
     direct_withheld_info: StdRwLock<HashMap<OwnedRoomId, HashMap<String, RoomKeyWithheldEntry>>>,
     custom_values: StdRwLock<HashMap<String, Vec<u8>>>,
     leases: StdRwLock<HashMap<String, Lease>>,
-    secret_inbox: StdRwLock<HashMap<String, Vec<GossippedSecret>>>,
+    secret_inbox: StdRwLock<HashMap<String, Vec<Zeroizing<String>>>>,
     backup_keys: RwLock<BackupKeys>,
     dehydrated_device_pickle_key: RwLock<Option<DehydratedDeviceKey>>,
     next_batch_token: RwLock<Option<String>>,
@@ -306,7 +307,7 @@ impl CryptoStore for MemoryStore {
         {
             let mut secret_inbox = self.secret_inbox.write();
             for secret in changes.secrets {
-                secret_inbox.entry(secret.secret_name.to_string()).or_default().push(secret);
+                secret_inbox.entry(secret.secret_name.to_string()).or_default().push(secret.secret);
             }
         }
 
@@ -749,7 +750,7 @@ impl CryptoStore for MemoryStore {
     async fn get_secrets_from_inbox(
         &self,
         secret_name: &SecretName,
-    ) -> Result<Vec<GossippedSecret>> {
+    ) -> Result<Vec<Zeroizing<String>>> {
         Ok(self.secret_inbox.write().entry(secret_name.to_string()).or_default().to_owned())
     }
 
@@ -1322,10 +1323,11 @@ mod integration_tests {
         DeviceId, OwnedDeviceId, RoomId, TransactionId, UserId, events::secret::request::SecretName,
     };
     use vodozemac::Curve25519PublicKey;
+    use zeroize::Zeroizing;
 
     use super::MemoryStore;
     use crate::{
-        Account, DeviceData, GossipRequest, GossippedSecret, SecretInfo, Session, UserIdentityData,
+        Account, DeviceData, GossipRequest, SecretInfo, Session, UserIdentityData,
         cryptostore_integration_tests, cryptostore_integration_tests_time,
         olm::{
             InboundGroupSession, OlmMessageHash, OutboundGroupSession, PrivateCrossSigningIdentity,
@@ -1593,7 +1595,7 @@ mod integration_tests {
         async fn get_secrets_from_inbox(
             &self,
             secret_name: &SecretName,
-        ) -> Result<Vec<GossippedSecret>, Self::Error> {
+        ) -> Result<Vec<Zeroizing<String>>, Self::Error> {
             self.0.get_secrets_from_inbox(secret_name).await
         }
 

crates/matrix-sdk-crypto/src/store/mod.rs

@@ -1,4 +1,4 @@
-// Copyright 2020 The Matrix.org Foundation C.I.C.
+// Copyright 2020, 2026 The Matrix.org Foundation C.I.C.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -76,7 +76,7 @@ use crate::{
         Account, ExportedRoomKey, ForwarderData, InboundGroupSession, PrivateCrossSigningIdentity,
         SenderData, Session, StaticAccountData,
     },
-    store::types::RoomKeyWithheldEntry,
+    store::types::{RoomKeyWithheldEntry, SecretsInboxItem},
     types::{
         BackupSecrets, CrossSigningSecrets, MegolmBackupV1Curve25519AesSha2Secrets, RoomKeyExport,
         SecretsBundle,
@@ -1381,7 +1381,7 @@ impl Store {
     /// }
     /// # });
     /// ```
-    pub fn secrets_stream(&self) -> impl Stream<Item = GossippedSecret> + use<> {
+    pub fn secrets_stream(&self) -> impl Stream<Item = SecretsInboxItem> + use<> {
         self.inner.store.secrets_stream()
     }
 

crates/matrix-sdk-crypto/src/store/traits.rs

@@ -1,4 +1,4 @@
-// Copyright 2023 The Matrix.org Foundation C.I.C.
+// Copyright 2023, 2026 The Matrix.org Foundation C.I.C.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@ use ruma::{
     DeviceId, OwnedDeviceId, RoomId, TransactionId, UserId, events::secret::request::SecretName,
 };
 use vodozemac::Curve25519PublicKey;
+use zeroize::Zeroizing;
 
 use super::{
     CryptoStoreError, Result,
@@ -31,7 +32,7 @@ use super::{
 #[cfg(doc)]
 use crate::olm::SenderData;
 use crate::{
-    Account, DeviceData, GossipRequest, GossippedSecret, SecretInfo, UserIdentityData,
+    Account, DeviceData, GossipRequest, SecretInfo, UserIdentityData,
     olm::{
         InboundGroupSession, OlmMessageHash, OutboundGroupSession, PrivateCrossSigningIdentity,
         SenderDataType, Session,
@@ -331,7 +332,7 @@ pub trait CryptoStore: AsyncTraitDeps {
     async fn get_secrets_from_inbox(
         &self,
         secret_name: &SecretName,
-    ) -> Result<Vec<GossippedSecret>, Self::Error>;
+    ) -> Result<Vec<Zeroizing<String>>, Self::Error>;
 
     /// Delete all the secrets with the given [`SecretName`] we have currently
     /// stored.
@@ -609,7 +610,7 @@ impl<T: CryptoStore> CryptoStore for EraseCryptoStoreError<T> {
     async fn get_secrets_from_inbox(
         &self,
         secret_name: &SecretName,
-    ) -> Result<Vec<GossippedSecret>> {
+    ) -> Result<Vec<Zeroizing<String>>> {
         self.0.get_secrets_from_inbox(secret_name).await.map_err(Into::into)
     }
 

crates/matrix-sdk-crypto/src/store/types.rs

@@ -1,4 +1,4 @@
-// Copyright 2020 The Matrix.org Foundation C.I.C.
+// Copyright 2020, 2026 The Matrix.org Foundation C.I.C.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -19,13 +19,17 @@
 
 use std::{
     collections::{BTreeMap, HashMap, HashSet},
+    ops::Deref,
     time::Duration,
 };
 
-use ruma::{MilliSecondsSinceUnixEpoch, OwnedDeviceId, OwnedRoomId, OwnedUserId};
-use serde::{Deserialize, Serialize};
+use ruma::{
+    MilliSecondsSinceUnixEpoch, OwnedDeviceId, OwnedRoomId, OwnedUserId,
+    events::secret::request::SecretName,
+};
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use vodozemac::{Curve25519PublicKey, base64_encode};
-use zeroize::{Zeroize, ZeroizeOnDrop};
+use zeroize::{Zeroize, ZeroizeOnDrop, Zeroizing};
 
 use super::{DehydrationError, GossipRequest};
 use crate::{
@@ -80,7 +84,7 @@ pub struct Changes {
     /// Stores when a `m.room_key.withheld` is received
     pub withheld_session_info: BTreeMap<OwnedRoomId, BTreeMap<String, RoomKeyWithheldEntry>>,
     pub room_settings: HashMap<OwnedRoomId, RoomSettings>,
-    pub secrets: Vec<GossippedSecret>,
+    pub secrets: Vec<SecretsInboxItem>,
     pub next_batch_token: Option<String>,
 
     /// Historical room key history bundles that we have received and should
@@ -96,6 +100,47 @@ pub struct Changes {
     pub rooms_pending_key_bundle: HashMap<OwnedRoomId, Option<RoomPendingKeyBundleDetails>>,
 }
 
+/// A secret that was received via an `m.secret.send`.
+#[derive(Clone, Serialize, Deserialize)]
+pub struct SecretsInboxItem {
+    /// The name of the secret.
+    pub secret_name: SecretName,
+    /// The contents of the secret.
+    #[serde(
+        serialize_with = "zeroizing_string_serializer",
+        deserialize_with = "zeroizing_string_deserializer"
+    )]
+    pub secret: Zeroizing<String>,
+}
+
+fn zeroizing_string_serializer<S>(x: &Zeroizing<String>, s: S) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    s.serialize_some(x.deref())
+}
+
+fn zeroizing_string_deserializer<'de, D>(deserializer: D) -> Result<Zeroizing<String>, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    let value = String::deserialize(deserializer)?;
+    Ok(value.into())
+}
+
+#[cfg(not(tarpaulin_include))]
+impl std::fmt::Debug for SecretsInboxItem {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_tuple("SecretsInboxItem").field(&self.secret_name).finish()
+    }
+}
+
+impl From<GossippedSecret> for SecretsInboxItem {
+    fn from(secret: GossippedSecret) -> Self {
+        Self { secret_name: secret.secret_name, secret: secret.event.content.secret.clone().into() }
+    }
+}
+
 /// Information about an [MSC4268] room key bundle.
 ///
 /// [MSC4268]: https://github.com/matrix-org/matrix-spec-proposals/pull/4268