From: Eric Paris <eparis@parisplace.org>
To: Roland McGrath <roland@hack.frob.com>
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 11:07:48 -0400 [thread overview]
Message-ID: <1319468868.3280.9.camel@localhost> (raw)
In-Reply-To: <20111023185243.EFE2F2C08F@topped-with-meat.com>
On Sun, 2011-10-23 at 11:52 -0700, Roland McGrath wrote:
> > But that's no reason for the kernel to *allow* the mapping.
>
> I don't have a problem with that.
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....
If that's the case, NULL pointer kernel bugs won't be caught if they
happen while these are mapped by your program...
--
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WARNING: multiple messages have this Message-ID (diff)
From: Eric Paris <eparis@parisplace.org>
To: Roland McGrath <roland@hack.frob.com>
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 11:07:48 -0400 [thread overview]
Message-ID: <1319468868.3280.9.camel@localhost> (raw)
In-Reply-To: <20111023185243.EFE2F2C08F@topped-with-meat.com>
On Sun, 2011-10-23 at 11:52 -0700, Roland McGrath wrote:
> > But that's no reason for the kernel to *allow* the mapping.
>
> I don't have a problem with that.
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....
If that's the case, NULL pointer kernel bugs won't be caught if they
happen while these are mapped by your program...
next prev parent reply other threads:[~2011-10-24 15:07 UTC|newest]
Thread overview: 11+ 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 [this message]
2011-10-24 15:07 ` Eric Paris
2011-10-24 16:28 ` Roland McGrath
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