On Thursday 22 September 2011 12:31:40 Andrew Richards wrote:
On Thursday 22 September 2011 00:45:32 Timo Sirainen wrote:
On 22.9.2011, at 1.59, Andrew Richards wrote:
I'm seeing a strange problem with some attachment filenames that are UTF-8 encoded. The problem seems to be related to spaces and/or unusual characters in filenames, like accented characters (or perhaps just to filenames if UTF-8 encoded; I've not explored that fully).
The problem is that the client sends it wrong:
Content-Type: application/octet-stream; name==?UTF-8?B?dGhpc19mYWlscy50eHQ=?= Content-Disposition: attachment; filename==?UTF-8?B?dGhpc19mYWlscy50eHQ=?=
These are both wrong. First of all they are illegal because they have = and
? characters, from RFC 2045:
...snip...
Also from RFC 2047 (encoded-word is the =?UTF-8?...?= thing):
- An 'encoded-word' MUST NOT be used in parameter of a MIME Content-Type or Content-Disposition field, or in any structured field body except within a 'comment' or 'phrase'.
...snip... Anyway .. I'll check tomorrow if I can easily add code to workaround your problem. If it's just a minor change I'll do it.
Wow - a very thorough response only 45 minutes after I'd posted the question, and in your follow up message you've already provided a suggested fix - a huge thank you!
So in summary it's a "Garbage in -> Garbage out" issue... This also explains why I'm only getting this issue with one client after a Courier->Dovecot migration. I'll research which mail client program(s) are generating the faulty messages for completeness for this thread.
I expect to test the fix later today or tomorrow, I'll update the thread accordingly when I've done so.
Firstly, my apologies - it's been a week before I've got back to this - I was making sense of another MIME issue which I thought might be related (it isn't), but I'll start a new thread for that.
The fix works just fine. However...
...regarding the broken MIME fields: These look to occur in the form I noted for a single client program only, which on further investigation turns out to be an in-house[-written] mail program of my client, and therefore this problem is unlikely to bite other people: I've had permission to search the client's mailboxes for similar non-conforming emails and they only occur for this one in-house mail program.
Summary: False alarm. However once again a huge thank-you to Timo for the patch to workaround this broken data.
Best regards,
Andrew.