Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes()

From	Kees Cook <keescook@chromium.org>
Newsgroups	linux.kernel
Subject	Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes()
Date	2016-09-07 19:10 +0200
Message-ID	<seOwi-2yo-21@gated-at.bofh.it> (permalink)
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On Wed, Sep 7, 2016 at 9:37 AM, Joe Perches <joe@perches.com> wrote:
> On Wed, 2016-09-07 at 09:23 -0700, Kees Cook wrote:
>> Fixing these kmalloc calls would be a nice thing to clean up
>> everywhere.
>
> Dubious as gcc cannot currently optimize known small fixed size
> allocations with alloc_array and will always perform the
> multiplication.

Oh, that's sad. Is it not able to tell what the types are to basic
overflow validation? Could we help gcc in some way?

> Also the style of sizeof(*ptr) is not always as clear, obvious
> nor as easy to grep as sizeof(type).

I've always been on the fence about this (I like being able to see
destination:thing, sizeof(*thing) for easy scanning), but having the
type right there can be easier for text searches.

-Kees

-- 
Kees Cook
Nexus Security

Thread

[PATCH] x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-04 22:30 +0200
  Re: [PATCH] x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() Kees Cook <keescook@chromium.org> - 2016-09-07 00:00 +0200
    Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-07 10:00 +0200
      Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() Paolo Bonzini <pbonzini@redhat.com> - 2016-09-07 12:40 +0200
        Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-07 13:30 +0200
          Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() Paolo Bonzini <pbonzini@redhat.com> - 2016-09-07 13:30 +0200
            Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-07 13:50 +0200
              Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() Kees Cook <keescook@chromium.org> - 2016-09-07 18:30 +0200
                Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() Joe Perches <joe@perches.com> - 2016-09-07 18:40 +0200
                Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() Kees Cook <keescook@chromium.org> - 2016-09-07 19:10 +0200
                Re: x86-ksysfs: Use kmalloc_array() in create_setup_data_nodes() SF Markus Elfring <elfring@users.sourceforge.net> - 2016-09-07 19:00 +0200

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