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From: zerons <zeronsaxm@gmail.com>
To: Kees Cook <keescook@chromium.org>
Cc: Alexander Popov <alex.popov@linux.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	kernel-hardening@lists.openwall.com,
	Shawn <citypw@hardenedlinux.org>,
	spender@grsecurity.net
Subject: Re: Maybe inappropriate use BUG_ON() in CONFIG_SLAB_FREELIST_HARDENED
Date: Tue, 18 Feb 2020 10:21:47 +0800	[thread overview]
Message-ID: <dc337497-8084-915c-be64-059ef7cc1538@gmail.com> (raw)
In-Reply-To: <202002171019.A7B4679@keescook>


> 
>>> In my opinion, this patch can somehow help attacker exploit this kind of bugs
>>> more reliable.
> 
> Why do you think this makes races easier to win?
> 

Sorry, not to make the races easier, but to make the exploitations
more reliable.

>> +Alexander Popov, who is the author of the double free check in
>> SLAB_FREELIST_HARDENED.
>>
>> Ah, so as long as the double free happens in a user process context,
>> you can retry triggering it until you succeed in winning the race to
>> reallocate the object (without causing slab freelist corruption, as it
>> would have had happened before SLAB_FREELIST_HARDENED). Nice idea!
> 
> Do you see improvements that could be made here?
> 

Could we use BUG_ON() only when panic_on_oops is set?

  reply	other threads:[~2020-02-18 11:08 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-13 15:16 Maybe inappropriate use BUG_ON() in CONFIG_SLAB_FREELIST_HARDENED zerons
2020-02-17 15:15 ` Andrey Konovalov
2020-02-17 18:23   ` Kees Cook
2020-02-18  2:21     ` zerons [this message]
2020-02-18 20:54   ` Alexander Popov
2020-02-19 13:43     ` zerons
2020-02-27 11:28       ` Alexander Popov
2020-03-08  0:44         ` zerons

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