fix: Use and prefer Date from signed message part (#5716)

src/mimeparser.rs

@@ -220,13 +220,8 @@ impl MimeMessage {
         let mail = mailparse::parse_mail(body)?;
 
         let timestamp_rcvd = smeared_time(context);
-        let timestamp_sent = mail
-            .headers
-            .get_header_value(HeaderDef::Date)
-            .and_then(|v| mailparse::dateparse(&v).ok())
-            .map_or(timestamp_rcvd, |value| {
-                min(value, timestamp_rcvd + constants::TIMESTAMP_SENT_TOLERANCE)
-            });
+        let mut timestamp_sent =
+            Self::get_timestamp_sent(&mail.headers, timestamp_rcvd, timestamp_rcvd);
         let mut hop_info = parse_receive_headers(&mail.get_headers());
 
         let mut headers = Default::default();
@@ -254,6 +249,8 @@ impl MimeMessage {
                     // We don't remove "subject" from `headers` because currently just signed
                     // messages are shown as unencrypted anyway.
 
+                    timestamp_sent =
+                        Self::get_timestamp_sent(&mail.headers, timestamp_sent, timestamp_rcvd);
                     MimeMessage::merge_headers(
                         context,
                         &mut headers,
@@ -349,6 +346,8 @@ impl MimeMessage {
             content
         });
         if let (Ok(mail), true) = (mail, encrypted) {
+            timestamp_sent =
+                Self::get_timestamp_sent(&mail.headers, timestamp_sent, timestamp_rcvd);
             if !signatures.is_empty() {
                 // Handle any gossip headers if the mail was encrypted. See section
                 // "3.6 Key Gossip" of <https://autocrypt.org/autocrypt-spec-1.1.0.pdf>
@@ -525,6 +524,18 @@ impl MimeMessage {
         Ok(parser)
     }
 
+    fn get_timestamp_sent(
+        hdrs: &[mailparse::MailHeader<'_>],
+        default: i64,
+        timestamp_rcvd: i64,
+    ) -> i64 {
+        hdrs.get_header_value(HeaderDef::Date)
+            .and_then(|v| mailparse::dateparse(&v).ok())
+            .map_or(default, |value| {
+                min(value, timestamp_rcvd + constants::TIMESTAMP_SENT_TOLERANCE)
+            })
+    }
+
     /// Parses system messages.
     fn parse_system_message_headers(&mut self, context: &Context) {
         if self.get_header(HeaderDef::AutocryptSetupMessage).is_some() && !self.incoming {

src/receive_imf/tests.rs

@@ -15,7 +15,7 @@ use crate::download::MIN_DOWNLOAD_LIMIT;
 use crate::imap::prefetch_should_download;
 use crate::imex::{imex, ImexMode};
 use crate::test_utils::{get_chat_msg, mark_as_verified, TestContext, TestContextManager};
-use crate::tools::SystemTime;
+use crate::tools::{time, SystemTime};
 
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_outgoing() -> Result<()> {
@@ -3326,6 +3326,22 @@ async fn test_bot_recv_existing_msg() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_wrong_date_in_imf_section() {
+    let mut tcm = TestContextManager::new();
+    let alice = &tcm.alice().await;
+    let bob = &tcm.bob().await;
+    let alice_chat_id = tcm.send_recv_accept(bob, alice, "hi").await.chat_id;
+    let time_before_sending = time();
+    let mut sent_msg = alice.send_text(alice_chat_id, "hi").await;
+    sent_msg.payload = sent_msg.payload.replace(
+        "Date:",
+        "Date: Tue, 29 Feb 1972 22:37:57 +0000\nX-Microsoft-Original-Date:",
+    );
+    let msg = bob.recv_msg(&sent_msg).await;
+    assert!(msg.timestamp_sent >= time_before_sending);
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_no_private_reply_to_blocked_account() -> Result<()> {
     let mut tcm = TestContextManager::new();