HTTPS+SSLVerifyClient require in <Directory>+big POST = Apache error

I was configuring MediaWiki to allow uploads and was getting an error in the browser about the POST data being too large (“does not allow request data with POST requests, or the amount of data provided in the request exceeds the capacity limit.”). I had a look in the Apache error log and found:

[Thu Feb 23 16:12:45 2012] [error] [client] request body exceeds m
aximum size (131072) for SSL buffer, referer:
[Thu Feb 23 16:12:45 2012] [error] [client] could not buffer messa
ge body to allow SSL renegotiation to proceed, referer:

So I did some research. I found this document, File upload size which suggested editing /etc/php5/apache2/php.ini which I did:

upload_max_filesize = 20M
post_max_size = 80M

That didn’t fix the problem though. I found Request entity too large which suggested checking my setting for LimitRequestBody, but that wasn’t the problem either.

Eventually I found Bug 491763 – HTTPS+SSLVerifyClient require in <Directory>+big POST = Apache error which suggested I needed to apply the SSLRenegBufferSize directive which I did like this:

  <Location /morpheus>
    SSLVerifyClient require
    SSLVerifyDepth 1
    SSLRenegBufferSize 20971520

And then after restarting Apache the problem was solved.