From: Vlastimil Babka <vbabka@suse.cz>
To: Florian Weimer <fweimer@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-x86_64@vger.kernel.org, linux-arch@vger.kernel.org
Cc: linux-mm <linux-mm@kvack.org>, Linux API <linux-api@vger.kernel.org>
Subject: Re: MPK: removing a pkey
Date: Fri, 24 Nov 2017 09:38:27 +0100 [thread overview]
Message-ID: <346db028-6f45-65d5-a531-300c2251a8eb@suse.cz> (raw)
In-Reply-To: <e97e53a1-ba04-c62e-cc64-054b488d5394@redhat.com>
On 11/24/2017 09:35 AM, Florian Weimer wrote:
> On 11/24/2017 12:29 AM, Dave Hansen wrote:
>> Although weird, the thought here was that pkey_mprotect() callers are
>> new and should know about the interactions with PROT_EXEC. They can
>> also*get* PROT_EXEC semantics if they want.
>>
>> The only wart here is if you do:
>>
>> mprotect(..., PROT_EXEC); // key 10 is now the PROT_EXEC key
>
> I thought the PROT_EXEC key is always 1?
Seems it assigns the first non-allocated one. Can even fail if there's
none left, and then there's no PROT_EXEC read protection. In practice I
expect PROT_EXEC mapping to be created by ELF loader (?) before the
program can even call pkey_alloc() itself, so it would be 1.
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next prev parent reply other threads:[~2017-11-24 8:39 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-05 10:35 MPK: pkey_free and key reuse Florian Weimer
2017-11-08 20:41 ` Dave Hansen
2017-11-09 14:48 ` Florian Weimer
2017-11-09 16:59 ` Dave Hansen
2017-11-23 12:48 ` Florian Weimer
2017-11-23 13:07 ` Vlastimil Babka
2017-11-23 15:25 ` Dave Hansen
2017-11-24 14:55 ` Florian Weimer
2017-11-22 8:18 ` MPK: removing a pkey (was: pkey_free and key reuse) Vlastimil Babka
2017-11-22 12:15 ` MPK: removing a pkey Florian Weimer
2017-11-22 12:46 ` Vlastimil Babka
2017-11-22 12:49 ` Florian Weimer
2017-11-22 16:10 ` Dave Hansen
2017-11-22 16:21 ` Florian Weimer
2017-11-22 16:32 ` Dave Hansen
2017-11-23 8:11 ` Vlastimil Babka
2017-11-23 15:00 ` Dave Hansen
2017-11-23 21:42 ` Vlastimil Babka
2017-11-23 23:29 ` Dave Hansen
2017-11-24 8:35 ` Florian Weimer
2017-11-24 8:38 ` Vlastimil Babka [this message]
2017-11-23 12:38 ` Florian Weimer
2017-11-23 15:09 ` Dave Hansen
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