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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Mon, 6 Apr 2020 10:26:37 -0700
Message-ID: <CAHk-=wiPHA4XbL-CVTDBwjYzUJwaGYriGD44uvOaqQai+zOw6A@mail.gmail.com>
Subject: Re: [PATCH] mm: Add kvfree_sensitive() for freeing sensitive data objects
To:     Joe Perches <joe@perches.com>
Cc:     David Howells <dhowells@redhat.com>,
        Waiman Long <longman@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        James Morris <jmorris@namei.org>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        Linux-MM <linux-mm@kvack.org>, keyrings@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Apr 6, 2020 at 10:12 AM Joe Perches <joe@perches.com> wrote:
>
> Add yet another alloc flag like __GFP_SENSITIVE
> and have kfree operate on that and not have a
> kfree_sensitive at all.

That sounds potentially sensible. Maybe even a SLAB_SENSITIVE to mark
a whole slab cache sensitive for kmem_cache_create().

I'm not sure how controlled the allocations are, though. The
allocations that get used for keys etc might come from outside the
crypto layer.

                Linus