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    SubjectRe: [PATCH v3] mm: Add kvfree_sensitive() for freeing sensitive data objects
    On Tue, Apr 07, 2020 at 04:03:18PM -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.
    >
    > Fixes: 4f0882491a14 ("KEYS: Avoid false positive ENOMEM error on key read")
    > Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
    > Signed-off-by: Waiman Long <longman@redhat.com>

    Looks good, feel free to add:

    Reviewed-by: Eric Biggers <ebiggers@google.com>

    (I don't really buy the argument that the compiler could compile away memset()
    before kvfree(). But I agree with using memzero_explicit() anyway to make the
    intent explicit.)

    I don't see this patch in linux-next yet. Who is planning to take this patch?
    Presumably David through the keyrings tree, or Andrew through mm?

    - Eric

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