From: dchinner@redhat.com (Dave Chinner)
To: linux-security-module@vger.kernel.org
Subject: [RFC PATCH v16 0/6] mm: security: ro protection for dynamic data
Date: Thu, 22 Feb 2018 08:36:29 +1100 [thread overview]
Message-ID: <20180221213629.GF3728@rh> (raw)
In-Reply-To: <46a9610a-182b-4765-9d83-cab6297377f3@huawei.com>
On Wed, Feb 21, 2018 at 11:56:22AM +0200, Igor Stoppa wrote:
> On 21/02/18 03:36, Dave Chinner wrote:
> > On Tue, Feb 20, 2018 at 03:56:00PM -0800, Matthew Wilcox wrote:
> >> On Wed, Feb 21, 2018 at 08:36:04AM +1100, Dave Chinner wrote:
> >>> FWIW, I'm not wanting to use it to replace static variables. All the
> >>> structures are dynamically allocated right now, and get assigned to
> >>> other dynamically allocated pointers. I'd likely split the current
> >>> structures into a "ro after init"
>
> I would prefer to use a different terminology, because, if I have
> understood the use case, this is not exactly the same as __ro_after_init
I want a dynamically allocated "write once" structure.
A "write once" structure is, conceptually, is exactly the same as
"ro after init". Implementation wise, it may be different to
"__ro_after_init", especially when compared to static/global
variables.
It seems lots of people get confused when discussing concepts vs
implementation... :)
> >>> ......
> >>
> >> No, you'd do:
> >>
> >> struct xfs_mount_ro {
> >> [...]
> >> };
>
> is this something that is readonly from the beginning and then shared
> among mount points or is it specific to each mount point?
It's dynamically allocated for each mount point, made read-only
before the mount completes and lives for the length of the mount
point.
> >> struct xfs_mount {
> >> const struct xfs_mount_ro *ro;
> >> [...]
> >> };
> >
> > .... so that's pretty much the same thing :P
>
> The "const" modifier is a nice way to catch errors through the compiler,
> iff the ro data will not be initialized through this handle, when it's
> still writable.
That's kinda implied by the const, isn't it? If we don't do it that
way, then the compiler will throw errors....
Cheers,
Dave.
--
Dave Chinner
dchinner at redhat.com
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next prev parent reply other threads:[~2018-02-21 21:36 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-12 16:52 [RFC PATCH v16 0/6] mm: security: ro protection for dynamic data Igor Stoppa
2018-02-12 16:52 ` [PATCH 1/6] genalloc: track beginning of allocations Igor Stoppa
2018-02-12 23:52 ` Kees Cook
2018-02-20 17:07 ` Igor Stoppa
2018-02-21 22:29 ` Kees Cook
2018-02-21 22:35 ` Jonathan Corbet
2018-02-12 16:52 ` [PATCH 2/6] genalloc: selftest Igor Stoppa
2018-02-12 23:50 ` Kees Cook
2018-02-20 16:59 ` Igor Stoppa
2018-02-21 22:28 ` Kees Cook
2018-02-22 9:14 ` Igor Stoppa
2018-02-22 18:28 ` Igor Stoppa
2018-02-12 16:52 ` [PATCH 3/6] struct page: add field for vm_struct Igor Stoppa
2018-02-12 16:52 ` [PATCH 4/6] Protectable Memory Igor Stoppa
2018-02-12 16:53 ` [PATCH 5/6] Pmalloc: self-test Igor Stoppa
2018-02-12 23:43 ` Kees Cook
2018-02-20 16:40 ` Igor Stoppa
2018-02-21 22:24 ` Kees Cook
2018-02-22 9:01 ` Igor Stoppa
2018-02-12 16:53 ` [PATCH 6/6] Documentation for Pmalloc Igor Stoppa
2018-02-12 23:32 ` [RFC PATCH v16 0/6] mm: security: ro protection for dynamic data Kees Cook
2018-02-20 1:21 ` Dave Chinner
2018-02-20 18:03 ` Igor Stoppa
2018-02-20 21:36 ` Dave Chinner
2018-02-20 23:56 ` Matthew Wilcox
2018-02-21 1:36 ` Dave Chinner
2018-02-21 9:56 ` Igor Stoppa
2018-02-21 21:36 ` Dave Chinner [this message]
2018-02-22 8:58 ` Igor Stoppa
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