Re: [PATCH 15/15] kasan: Add mititgation and debug modes - Maciej Wieczor-Retman

From: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
To: Andrey Konovalov <andreyknvl@gmail.com>
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Subject: Re: [PATCH 15/15] kasan: Add mititgation and debug modes
Date: Fri, 7 Feb 2025 10:08:17 +0100	[thread overview]
Message-ID: <mngxg6wmbfzw62yhlavo6qcx3wsdkdgz3qsxahfjbs2bngxicp@7pbj2i2a6nah> (raw)
In-Reply-To: <CA+fCnZcG0nv1_ezc+yu3Wj_7iS0r_QfK9OcDnK-MRmJ=BF4iJg@mail.gmail.com>

On 2025-02-06 at 00:46:21 +0100, Andrey Konovalov wrote:
>On Tue, Feb 4, 2025 at 6:37 PM Maciej Wieczor-Retman
><maciej.wieczor-retman@intel.com> wrote:
...
>> +choice
>> +       prompt "KASAN operation mode"
>> +       default KASAN_OPERATION_DEBUG
>> +       help
>> +         Choose between the mitigation or debug operation modes.
>> +
>> +         The first one disables stacktrace saving and enables panic on error.
>> +         Faster memory allocation but less information. The second one is the
>> +         default where KASAN operates with full functionality.
>
>This is something that I thought about before and I think we should
>_not_ add configuration options like these. The distinction between
>debug and mitigation modes is something that's specific to a
>particular user of the feature. Some might prefer to take the impact
>of having stack traces enabled in a production environment to allow
>debugging in-the-wild exploitation attempts. Also at some point in the
>future, we will hopefully have production-grade stack traces [1], and
>this would thus change the desired behavior of
>KASAN_OPERATION_MITIGATION.
>
>We already have the kasan.stacktrace command-line parameter for
>disabling stack trace collection. On top of that, if you prefer, we
>could add a configuration option that changes the default value of
>kasan_flag_stacktrace (but can still be overridden via the
>kasan.stacktrace command-line parameter). Note though that by default,
>stack traces should be turned on.
>
>[1] https://bugzilla.kernel.org/show_bug.cgi?id=211785
>

Okay, I see your point. I'll drop the patch for now and rethink if messing with
how stacktraces are enabled/disabled is worth it.

>
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-- 
Kind regards
Maciej Wieczór-Retman