Re: Inquiry Regarding Backslash Handling in Reply-Message

Nick Porter <[email protected]> Wed, 10 Sep 2025 20:35:19 +0100

Newsgroups	gmane.comp.freeradius.user
Message-ID	<[email protected]>

On 10/09/2025 18:34, Alan DeKok via Freeradius-Users wrote:
> On Sep 3, 2025, at 7:09 AM, 平林 哲<[email protected]> wrote:
>> We have encountered an issue in FreeRADIUS version 3.2.8 where the backslash (`\`) character in the `Reply-Message` configured for a user is not correctly reflected in the response.

Some experimentation and digging into the code shows that when your 
entries are of the form

radiusAttribute: Reply-Message += 'mess\\age'

the value being assigned to the attribute gets un-escaped twice - which 
is why you're seeing four \ being reduced to one.

If you omit the '' around the value then it is only un-escaped once

i.e.

radiusAttribute: Reply-Message += mess\\\\age

will result in two \ in the final value.

As Alan indicated it's a non-trivial fix - the same escaping / 
un-escaping routines are used by multiple code paths so there is risk of 
changing existing behaviour if they are amended.

Nick

Nick Porter

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