fix: Use keyring with all private keys when decrypting a message (#5046)

Before a keyring with the only default key was used, i.e. the key used for signing and encrypting to
self.

src/imex.rs

@@ -808,6 +808,7 @@ mod tests {
     use tokio::task;
 
     use super::*;
+    use crate::key;
     use crate::pgp::{split_armored_data, HEADER_AUTOCRYPT, HEADER_SETUPCODE};
     use crate::stock_str::StockMessage;
     use crate::test_utils::{alice_keypair, TestContext};
@@ -920,6 +921,37 @@ mod tests {
         }
     }
 
+    #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+    async fn test_import_second_key() -> Result<()> {
+        let alice = &TestContext::new_alice().await;
+        let chat = alice.create_chat(alice).await;
+        let sent = alice.send_text(chat.id, "Encrypted with old key").await;
+        let export_dir = tempfile::tempdir().unwrap();
+
+        let alice = &TestContext::new().await;
+        alice.configure_addr("alice@example.org").await;
+        imex(alice, ImexMode::ExportSelfKeys, export_dir.path(), None).await?;
+
+        let alice = &TestContext::new_alice().await;
+        let old_key = key::load_self_secret_key(alice).await?;
+
+        imex(alice, ImexMode::ImportSelfKeys, export_dir.path(), None).await?;
+
+        let new_key = key::load_self_secret_key(alice).await?;
+        assert_ne!(new_key, old_key);
+        assert_eq!(
+            key::load_self_secret_keyring(alice).await?,
+            vec![new_key, old_key]
+        );
+
+        let msg = alice.recv_msg(&sent).await;
+        assert!(msg.get_showpadlock());
+        assert_eq!(msg.chat_id, alice.get_self_chat().await.id);
+        assert_eq!(msg.get_text(), "Encrypted with old key");
+
+        Ok(())
+    }
+
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
     async fn test_export_and_import_backup() -> Result<()> {
         for set_verified_oneonone_chats in [true, false] {

src/key.rs

@@ -16,6 +16,7 @@ use tokio::runtime::Handle;
 use crate::config::Config;
 use crate::constants::KeyGenType;
 use crate::context::Context;
+use crate::log::LogExt;
 use crate::pgp::KeyPair;
 use crate::tools::{time, EmailAddress};
 
@@ -125,6 +126,25 @@ pub(crate) async fn load_self_secret_key(context: &Context) -> Result<SignedSecr
     }
 }
 
+pub(crate) async fn load_self_secret_keyring(context: &Context) -> Result<Vec<SignedSecretKey>> {
+    let keys = context
+        .sql
+        .query_map(
+            r#"SELECT private_key
+               FROM keypairs
+               WHERE addr=(SELECT value FROM config WHERE keyname="configured_addr")
+               ORDER BY is_default DESC"#,
+            (),
+            |row| row.get::<_, Vec<u8>>(0),
+            |keys| keys.collect::<Result<Vec<_>, _>>().map_err(Into::into),
+        )
+        .await?
+        .into_iter()
+        .filter_map(|bytes| SignedSecretKey::from_slice(&bytes).log_err(context).ok())
+        .collect();
+    Ok(keys)
+}
+
 impl DcKey for SignedPublicKey {
     fn to_asc(&self, header: Option<(&str, &str)>) -> String {
         // Not using .to_armored_string() to make clear *why* it is

src/mimeparser.rs

@@ -27,7 +27,7 @@ use crate::decrypt::{
 use crate::dehtml::dehtml;
 use crate::events::EventType;
 use crate::headerdef::{HeaderDef, HeaderDefMap};
-use crate::key::{load_self_secret_key, DcKey, Fingerprint, SignedPublicKey};
+use crate::key::{load_self_secret_keyring, DcKey, Fingerprint, SignedPublicKey};
 use crate::message::{
     self, set_msg_failed, update_msg_state, Message, MessageState, MsgId, Viewtype,
 };
@@ -264,9 +264,7 @@ impl MimeMessage {
         headers.remove("chat-verified");
 
         let from = from.context("No from in message")?;
-        let private_keyring = vec![load_self_secret_key(context)
-            .await
-            .context("Failed to get own key")?];
+        let private_keyring = load_self_secret_keyring(context).await?;
 
         let mut decryption_info =
             prepare_decryption(context, &mail, &from.addr, message_time).await?;