• Eric Biggers's avatar
    crypto: ccm - fix incompatibility between "ccm" and "ccm_base" · 654a509d
    Eric Biggers authored
    commit 6a1faa4a43f5fabf9cbeaa742d916e7b5e73120f upstream.
    
    CCM instances can be created by either the "ccm" template, which only
    allows choosing the block cipher, e.g. "ccm(aes)"; or by "ccm_base",
    which allows choosing the ctr and cbcmac implementations, e.g.
    "ccm_base(ctr(aes-generic),cbcmac(aes-generic))".
    
    However, a "ccm_base" instance prevents a "ccm" instance from being
    registered using the same implementations.  Nor will the instance be
    found by lookups of "ccm".  This can be used as a denial of service.
    Moreover, "ccm_base" instances are never tested by the crypto
    self-tests, even if there are compatible "ccm" tests.
    
    The root cause of these problems is that instances of the two templates
    use different cra_names.  Therefore, fix these problems by making
    "ccm_base" instances set the same cra_name as "ccm" instances, e.g.
    "ccm(aes)" instead of "ccm_base(ctr(aes-generic),cbcmac(aes-generic))".
    
    This requires extracting the block cipher name from the name of the ctr
    and cbcmac algorithms.  It also requires starting to verify that the
    algorithms are really ctr and cbcmac using the same block cipher, not
    something else entirely.  But it would be bizarre if anyone were
    actually using non-ccm-compatible algorithms with ccm_base, so this
    shouldn't break anyone in practice.
    
    Fixes: 4a49b499 ("[CRYPTO] ccm: Added CCM mode")
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
    Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    
    654a509d