linux-kernel - Re: [PATCH] mm: Add kvfree_sensitive() for freeing sensitive data objects

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Date:   Mon, 06 Apr 2020 08:45:18 -0700
From:   Joe Perches <joe@...ches.com>
To:     Waiman Long <longman@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        David Howells <dhowells@...hat.com>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        James Morris <jmorris@...ei.org>,
        "Serge E. Hallyn" <serge@...lyn.com>
Cc:     linux-mm@...ck.org, keyrings@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH] mm: Add kvfree_sensitive() for freeing sensitive data
 objects

On Sun, 2020-04-05 at 22:37 -0400, Waiman Long wrote:
> For kvmalloc'ed data object that contains sensitive information like
> cryptographic key, we need to make sure that the buffer is always
> cleared before freeing it. Using memset() alone for buffer clearing may
> not provide certainty as the compiler may compile it away. To be sure,
> the special memzero_explicit() has to be used.
> 
> This patch introduces a new kvfree_sensitive() for freeing those
> sensitive data objects allocated by kvmalloc(). The relevnat places
> where kvfree_sensitive() can be used are modified to use it.

Why isn't this called kvzfree like the existing kzfree?