nullmailer appends @mailname to MIME-Header encoded, fully qualified From: address

[fschlich]

I use nullmailer to send an email from a generated text file. The tool that generates the file encodes the From: header with the MIME-Header encoding according to RFC2047. In my case, this looks like so:

From: =?UTF-8?B?RmxvcmlhbiBTY2hsaWNodGluZyA8ZnNmc0BkZWJpYW4ub3JnPg==?=

However nullmailer doesn't seem to recognize the encoding, and treating it as if it was an unqualified localpart, blindly adds @$mailname resulting in

From: =?UTF-8?B?RmxvcmlhbiBTY2hsaWNodGluZyA8ZnNmc0BkZWJpYW4ub3JnPg==?=@fschlich.dialup.fu-berlin.de

or, when decoded

From: Florian Schlichting <[email protected]>@fschlich.dialup.fu-berlin.de

An example of this can be seen at https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=993667

Before making decisions about "fixing" a header, nullmailer must correctly decode the header.