Avoid double encrypting PGP parts encoded as plain text (fixes #1083)

crates/jmap/src/email/crypto.rs

@@ -17,7 +17,7 @@ use common::{auth::AccessToken, Server};
 use directory::backend::internal::manage;
 use jmap_proto::types::{collection::Collection, property::Property};
 use mail_builder::{encoders::base64::base64_encode_mime, mime::make_boundary};
-use mail_parser::{decoders::base64::base64_decode, Message, MessageParser, MimeHeaders};
+use mail_parser::{decoders::base64::base64_decode, Message, MessageParser, MimeHeaders, PartType};
 use openpgp::{
     parse::Parse,
     serialize::stream,
@@ -372,7 +372,7 @@ impl EncryptMessage for Message<'_> {
     }
 
     fn is_encrypted(&self) -> bool {
-        self.content_type().is_some_and(|ct| {
+        if self.content_type().is_some_and(|ct| {
             let main_type = ct.c_type.as_ref();
             let sub_type = ct
                 .c_subtype
@@ -390,7 +390,37 @@ impl EncryptMessage for Message<'_> {
                         }))))
                 || (main_type.eq_ignore_ascii_case("multipart")
                     && sub_type.eq_ignore_ascii_case("encrypted"))
-        })
+        }) {
+            return true;
+        }
+
+        if self.parts.len() <= 2 {
+            let mut text_part = None;
+            let mut is_multipart = false;
+
+            for part in &self.parts {
+                match &part.body {
+                    PartType::Text(text) => {
+                        text_part = Some(text.as_ref());
+                    }
+                    PartType::Multipart(_) => {
+                        is_multipart = true;
+                    }
+                    _ => (),
+                }
+            }
+
+            match text_part {
+                Some(text) if self.parts.len() == 1 || is_multipart => {
+                    if text.trim_start().starts_with("-----BEGIN PGP MESSAGE-----") {
+                        return true;
+                    }
+                }
+                _ => (),
+            }
+        }
+
+        false
     }
 }
 

tests/resources/crypto/is_encrypted.txt

@@ -4,14 +4,14 @@ Content-Type: multipart/encrypted;
         boundary="17778885806d6b28_46555a54adda6fa5_d83705f326a6b951"
 
 body
----
+!!!
 Subject: FALSE
 Content-Type: multipart/signed;
         protocol="application/pkcs7-signature";
         boundary="17778885806d6b28_46555a54adda6fa5_d83705f326a6b951"
 
 body
----
+!!!
 Subject: TRUE
 Content-Type: application/pkcs7-mime;
         name="smime.p7m";
@@ -21,7 +21,7 @@ Content-Disposition: attachment;
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: TRUE
 Content-Type: application/pkcs7-signature;
         name="smime.p7s"; smime-type="signed-data"
@@ -30,7 +30,7 @@ Content-Disposition: attachment;
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: TRUE
 Content-Type: application/octet-stream;
         name="smime.p7m"
@@ -39,14 +39,14 @@ Content-Disposition: attachment;
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: TRUE
 Content-Type: application/octet-stream;
         name="smime.p7m"
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: TRUE
 Content-Type: application/octet-stream
 Content-Disposition: attachment;
@@ -54,7 +54,7 @@ Content-Disposition: attachment;
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: TRUE
 Content-Type: application/octet-stream
 Content-Disposition: attachment;
@@ -62,7 +62,7 @@ Content-Disposition: attachment;
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: TRUE
 Content-Type: application/octet-stream
 Content-Disposition: attachment;
@@ -70,7 +70,7 @@ Content-Disposition: attachment;
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: TRUE
 Content-Type: application/octet-stream
 Content-Disposition: attachment;
@@ -78,7 +78,7 @@ Content-Disposition: attachment;
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: FALSE
 Content-Type: application/octet-stream
 Content-Disposition: attachment;
@@ -86,16 +86,126 @@ Content-Disposition: attachment;
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: FALSE
 Content-Type: application/octet-stream
 Content-Disposition: attachment
 Content-Transfer-Encoding: base64
 
 body
----
+!!!
 Subject: FALSE
 Content-Type: multipart/mixed;
         boundary="17778885806d6b28_46555a54adda6fa5_d83705f326a6b951"
 
 body
+!!!
+Subject: TRUE
+Content-Type: multipart/mixed; boundary="----sinikael-?=_1-17364333937490.28304631087789"
+
+------sinikael-?=_1-17364333937490.28304631087789
+Content-Type: text/plain
+Content-Transfer-Encoding: quoted-printable
+
+
+-----BEGIN PGP MESSAGE-----
+Version: Mailvelope v6.0.1
+Comment: https://mailvelope.com
+
+wcFMAy3n9oegk2NSARAApgl4nuztm5uxuCe+7ISW9Ox+315/pCHZmOUibORX
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+=3DaQyM
+-----END PGP MESSAGE-----
+
+------sinikael-?=_1-17364333937490.28304631087789--
+!!!
+Subject: TRUE
+Content-Type: text/plain
+Content-Transfer-Encoding: quoted-printable
+
+
+
+-----BEGIN PGP MESSAGE-----
+Version: Mailvelope v6.0.1
+Comment: https://mailvelope.com
+
+wcFMAy3n9oegk2NSARAApgl4nuztm5uxuCe+7ISW9Ox+315/pCHZmOUibORX
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+=3DaQyM
+-----END PGP MESSAGE-----

tests/src/jmap/crypto.rs

@@ -241,7 +241,7 @@ pub fn check_is_encrypted() {
     )
     .unwrap();
 
-    for raw_message in messages.split("---") {
+    for raw_message in messages.split("!!!") {
         let is_encrypted = raw_message.contains("TRUE");
         let message = MessageParser::new()
             .parse(raw_message.trim().as_bytes())