Fix the content encoding for GPG-signed messages.
To remove the Mime-Version header field for the signed message part, the
raw message is parsed with go-message. go-message.Read(), however,
decodes the message body as well (i.e. from quoted-printable to UTF8
depending on the Content-Transfer-Encoding header). This means that the
msg.Body field now contains the decoded message (it is no longer encoded
as quoted-printable). We never encode the message back to the proper
Content-Transfer-Encoding.
To fix this, use net/mail.ReadMessage() to parse the headers and to not
decode the message body.
To verify the issue, send a signed message with the following text:
"19+1=20!"
The message will be properly signed, but the text is wrong; it shows
"19+1 !"; instead it should read "19+1=3D20!".
Fixes: 5e443bce ("gpg: fix mime-version header position")
References: https://todo.sr.ht/~rjarry/aerc/79
Signed-off-by: Koni Marti <koni.marti@gmail.com>
---
Acked-by: Robin Jarry <robin@jarry.cc>
Applied, thanks.
To git@git.sr.ht:~rjarry/aerc
3ce5670fdcb3..7346d20343b9 master -> master
lib/crypto/gpg/writer.go | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/lib/crypto/gpg/writer.go b/lib/crypto/gpg/writer.go
index caae56bf..c879bc7f 100644
--- a/lib/crypto/gpg/writer.go+++ b/lib/crypto/gpg/writer.go
@@ -8,6 +8,7 @@ import (
"fmt"
"io"
"mime"
+ "net/mail" "git.sr.ht/~rjarry/aerc/lib/crypto/gpg/gpgbin"
"github.com/emersion/go-message"
@@ -51,10 +52,11 @@ func (s *Signer) Write(p []byte) (int, error) {
}
func (s *Signer) Close() (err error) {
- msg, err := message.Read(&s.signedMsg)+ msg, err := mail.ReadMessage(&s.signedMsg) if err != nil {
return err
}
+ header := message.HeaderFromMap(msg.Header) // Make sure that MIME-Version is *not* set on the signed part header.
// It must be set *only* on the top level header.
//
@@ -64,10 +66,10 @@ func (s *Signer) Close() (err error) {
//
// Since the signature is computed on the whole part, including its
// header, changing the case can cause the signature to become invalid.
- msg.Header.Del("Mime-Version")+ header.Del("Mime-Version") var buf bytes.Buffer
- _ = textproto.WriteHeader(&buf, msg.Header.Header)+ _ = textproto.WriteHeader(&buf, header.Header) _, _ = io.Copy(&buf, msg.Body)
sig, micalg, err := gpgbin.Sign(bytes.NewReader(buf.Bytes()), s.from)
--
2.45.2