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author | Koni Marti <koni.marti@gmail.com> | 2024-08-23 20:12:56 +0200 |
---|---|---|
committer | Robin Jarry <robin@jarry.cc> | 2024-08-24 15:49:17 +0200 |
commit | 7346d20343b9fa8b192c9a5294b26efac9186c4f (patch) | |
tree | 6737fd56133a963cae415d7893c6db5de64f346b /lib/crypto/gpg | |
parent | 3ce5670fdcb39cab15000c6248adfd127fd8b398 (diff) | |
download | aerc-7346d20343b9fa8b192c9a5294b26efac9186c4f.tar.gz |
gpg: fix signed message encoding
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>
Tested-by: Jens Grassel <jens@wegtam.com>
Acked-by: Robin Jarry <robin@jarry.cc>
Diffstat (limited to 'lib/crypto/gpg')
-rw-r--r-- | lib/crypto/gpg/writer.go | 8 |
1 files 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) |