Removing Null Character from Query Parameter

Maxim Dounin mdounin at
Thu Jun 25 16:48:20 UTC 2020


On Thu, Jun 25, 2020 at 11:33:29AM -0400, anish10dec wrote:

> Nginx Upstream returning 400 Bad Request if null character is being passed
> in the request as part of uri or query params.
> Is there a way Null Character can be removed from request before proxying 
> it to upstream.
> Its only known from access logs that null character is being passed in
> request as \x00 and causing the failure

The null character is not allowed in the HTTP request line, and 
hence nginx returns 400 (Bad Request) error.

> How to identify the Null Character and remove it ? 

You can't.  Instead, consider fixing the client to generate HTTP 
requests correctly.

Maxim Dounin

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