legacy-display: accept text/plain legacy display parts

https://www.ietf.org/id/draft-autocrypt-lamps-protected-headers-02.html
Makes it clear that the "Legacy Display" part of an encrypted message
with protected headers can (and indeed, should) be of content-type
text/plain, though some clients still generate the Legacy Display part
as content-type text/rfc822-headers.  Notmuch should recognize the
part whichever of the two content-types it uses.

See also discussion in
https://github.com/autocrypt/protected-headers/issues/23 for why the
community of implementers is moving in the direction of text/plain.

Signed-off-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
This commit is contained in:
Daniel Kahn Gillmor 2019-12-24 17:05:44 -05:00 committed by David Bremner
parent cedc6db19d
commit 5aa60342c8

View file

@ -49,8 +49,14 @@ _notmuch_crypto_payload_has_legacy_display (GMimeObject *payload)
if (g_mime_multipart_get_count (mpayload) != 2)
return false;
first = g_mime_multipart_get_part (mpayload, 0);
if (! g_mime_content_type_is_type (g_mime_object_get_content_type (first),
"text", "rfc822-headers"))
/* Early implementations that generated "Legacy Display" parts used
Content-Type: text/rfc822-headers, but text/plain is more widely
rendered, so it is now the standard choice. We accept either as a
Legacy Display part. */
if (! (g_mime_content_type_is_type (g_mime_object_get_content_type (first),
"text", "plain") ||
g_mime_content_type_is_type (g_mime_object_get_content_type (first),
"text", "rfc822-headers")))
return false;
protected_header_parameter = g_mime_object_get_content_type_parameter (first, "protected-headers");
if ((! protected_header_parameter) || strcmp (protected_header_parameter, "v1"))