Re: [PATCH] LSM: Make security_hook_heads a local variable.

From	Casey Schaufler <casey@schaufler-ca.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] LSM: Make security_hook_heads a local variable.
Date	2017-05-22 22:40 +0200
Message-ID	<tK2hs-1Tl-29@gated-at.bofh.it> (permalink)
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On 5/22/2017 12:50 PM, Igor Stoppa wrote:
> On 22/05/17 18:09, Casey Schaufler wrote:
>> On 5/22/2017 7:03 AM, Christoph Hellwig wrote:
> [...]
>
>>> But even with those we can still chain
>>> them together with a list with external linkage.
>> I gave up that approach in 2012. Too many unnecessary calls to
>> null functions, and massive function vectors with a tiny number
>> of non-null entries. From a data structure standpoint, it was
>> just wrong. The list scheme is exactly right for the task at
>> hand.
> I understand this as a green light, for me to continue with the plan of
> using LSM Hooks as example for making dynamically allocated data become
> read-only, using also Tetsuo's patch (thanks, btw).

I still don't like the assumption that a structure of
N elements can be assumed to be the same as an array
of N elements. Putting on my hardening hat, however, I
like the smalloc() solution to keeping the hook lists
safe, so I am willing to swallow the objection to using
offsets to address the existing exposure.

>
> Is that correct?
>
> ---
> thanks, igor
> --
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Thread

[RFC v3]mm: ro protection for data allocated dynamically  Igor Stoppa <igor.stoppa@huawei.com> - 2017-05-19 12:40 +0200
  [PATCH 1/1] Sealable memory support Igor Stoppa <igor.stoppa@huawei.com> - 2017-05-19 12:50 +0200
    Re: [kernel-hardening] [PATCH 1/1] Sealable memory support Greg KH <gregkh@linuxfoundation.org> - 2017-05-20 11:00 +0200
      [PATCH] LSM: Make security_hook_heads a local variable. Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-05-21 13:20 +0200
        Re: [PATCH] LSM: Make security_hook_heads a local variable. Christoph Hellwig <hch@infradead.org> - 2017-05-22 16:10 +0200
          Re: [PATCH] LSM: Make security_hook_heads a local variable. Casey Schaufler <casey@schaufler-ca.com> - 2017-05-22 17:10 +0200
            Re: [PATCH] LSM: Make security_hook_heads a local variable. Igor Stoppa <igor.stoppa@huawei.com> - 2017-05-22 22:00 +0200
              Re: [PATCH] LSM: Make security_hook_heads a local variable. Casey Schaufler <casey@schaufler-ca.com> - 2017-05-22 22:40 +0200
                Re: [PATCH] LSM: Make security_hook_heads a local variable. Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> - 2017-05-22 22:50 +0200
      Re: [kernel-hardening] [PATCH 1/1] Sealable memory support Igor Stoppa <igor.stoppa@huawei.com> - 2017-05-22 21:50 +0200
    Re: [PATCH 1/1] Sealable memory support Kees Cook <keescook@chromium.org> - 2017-05-22 23:40 +0200
      Re: [PATCH 1/1] Sealable memory support Igor Stoppa <igor.stoppa@huawei.com> - 2017-05-23 11:50 +0200
        Re: [PATCH 1/1] Sealable memory support Kees Cook <keescook@google.com> - 2017-05-24 00:40 +0200
          Re: [PATCH 1/1] Sealable memory support Igor Stoppa <igor.stoppa@huawei.com> - 2017-05-24 19:50 +0200

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