From: Roland McGrath <roland@hack.frob.com>
To: Eric Paris <eparis@parisplace.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
James Morris <jmorris@namei.org>,
Stephen Smalley <sds@tycho.nsa.gov>,
selinux@tycho.nsa.gov,
John Johansen <john.johansen@canonical.com>,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] LSM: Do not apply mmap_min_addr check to PROT_NONE mappings
Date: Mon, 24 Oct 2011 09:28:42 -0700 (PDT) [thread overview]
Message-ID: <20111024162842.CE1942C09C@topped-with-meat.com> (raw)
In-Reply-To: Eric Paris's message of Monday, 24 October 2011 11:07:48 -0400 <1319468868.3280.9.camel@localhost>
> I feel like, and it's just a very vague feeling, that the PROT bits
> didn't matter to the kernel. It would still happily execute stuff on
> page 0 even without PROT_EXEC at some point in the past. I'm probably
> totally off base, and I could test it, but I sort of feel like I
> remember something like that....
Saying that PROT_EXEC might not be enforced is quite a different thing than
saying "PROT bits don't matter". It's certainly the case that in some past
kernel versions, some hardware (older x86 chips), some configurations (x86
non-PAE), and some modes (READ_IMPLIES_EXEC personality stuff), what you
can read, you can execute. I sincerely doubt it's ever been the case that
anything mapped as PROT_NONE could be accessed in any manner.
Thanks,
Roland
prev parent reply other threads:[~2011-10-24 16:28 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-21 21:39 [PATCH 1/2] LSM: Do not apply mmap_min_addr check to PROT_NONE mappings Roland McGrath
2011-10-21 21:39 ` [PATCH 2/2] SELinux: Do not apply MMAP_ZERO " Roland McGrath
2011-10-22 3:38 ` [PATCH 1/2] LSM: Do not apply mmap_min_addr " Linus Torvalds
2011-10-22 17:24 ` Roland McGrath
2011-10-22 18:32 ` Linus Torvalds
2011-10-22 18:41 ` Linus Torvalds
[not found] ` <20111023100835.14682pfbxag3lkao@guarana.org>
[not found] ` <CA+55aFydaGYx2nkeGps2kO2k=eV1m6xcFgH5okeqy1G8H=z+_w@mail.gmail.com>
2011-10-23 5:21 ` Kevin Easton
2011-10-23 18:52 ` Roland McGrath
2011-10-24 15:07 ` Eric Paris
2011-10-24 16:28 ` Roland McGrath [this message]
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