[mu4e bug] No encrypted flag for more Outlook S/MIME message types

[Cerebus]

Unlike #2745, this one is doesn't carry smime-type.

> mu find subject:"XXXX" -o json | jq '.[] | [.[":path"], .[":flags"]]'
[
  "/Users/xxxxxx/Maildir/INBOX/cur/1730987617.1304_1.xxxxxx,U=2477:2,RS",
  {
    "replied": "seen",
    "attach": "personal"
  }
]

Message content headers:

Content-Type: application/pkcs7-mime; name="smime.p7m"
Content-Disposition: attachment; filename="smime.p7m"
Content-Transfer-Encoding: base64
MIME-Version: 1.0

The attachment is:

> cat 1730987617.1304_1.xxxxxx,U=2477:2,RS | openssl smime -pk7out | openssl pkcs7 -print
PKCS7:
  type: pkcs7-envelopedData (1.2.840.113549.1.7.3)
  d.enveloped:
    version: 0

How to Reproduce Get someone on Outlook to send you S/MIME emails, I guess? I'm even sure which version b/c there's no MUA identifier in the headers. I think in this case it's Outlook/Mac but not sure.

And people wonder why MUA authors hate S/MIME. :(

Environment mu version 1.12.7 Emacs 29.4 macOS 14.7.1

Checklist

• [x] you are running either an 1.10.x/1.12.x release or master (otherwise please upgrade)
• [x] you can reproduce the problem without 3rd party extensions (including Doom/Evil, various extensions etc.)
• [x] you have read all of the above

[djcb]

Can you please attach a message where this happens? Otherwise we can't do anything with this, thanks.

[Cerebus]

message.txt

[djcb]

Thanks... I'll put a work-around in place.