[PATCH] parser: Don't crash when From: is list email but has weird mangle format

[Stephen Finucane]

On Wed, 2020-04-15 at 19:06 +1000, Andrew Donnellan wrote:
> get_original_sender() tries to demangle DMARC-mangled From headers, in
> the case where the email's From address is the list address. It knows how
> to handle Google Groups and Mailman style mangling, where the original
> submitter's name will be turned into e.g. "Andrew Donnellan via
> linuxppc-dev".
> 
> If an email has the From header set to the list address but has a name that
> doesn't include " via ", we'll throw an exception because stripped_name
> hasn't been set. Sometimes this is because the list name is seemingly
> empty, resulting in a mangled name like "Andrew Donnellan via"
> without the space after "via" that we detect. Handle this as well as we can
> instead, and add a test.
> 
> Fixes: 8279a84238c10 ("parser: Unmangle From: headers that have been mangled for DMARC purposes")
> Reported-by: Jeremy Kerr <jk at ozlabs.org>
> Signed-off-by: Andrew Donnellan <ajd at linux.ibm.com>

Looks good to me.

Reviewed-by: Stephen Finucane <stephen at that.guru>

---
> 
> Backport to stable?

Merged to master and backported to stable.

Stephen