• Eric Biggers's avatar
    crypto: hash - annotate algorithms taking optional key · 8d906d18
    Eric Biggers authored
    commit a208fa8f upstream.
    
    We need to consistently enforce that keyed hashes cannot be used without
    setting the key.  To do this we need a reliable way to determine whether
    a given hash algorithm is keyed or not.  AF_ALG currently does this by
    checking for the presence of a ->setkey() method.  However, this is
    actually slightly broken because the CRC-32 algorithms implement
    ->setkey() but can also be used without a key.  (The CRC-32 "key" is not
    actually a cryptographic key but rather represents the initial state.
    If not overridden, then a default initial state is used.)
    
    Prepare to fix this by introducing a flag CRYPTO_ALG_OPTIONAL_KEY which
    indicates that the algorithm has a ->setkey() method, but it is not
    required to be called.  Then set it on all the CRC-32 algorithms.
    
    The same also applies to the Adler-32 implementation in Lustre.
    
    Also, the cryptd and mcryptd templates have to pass through the flag
    from their underlying algorithm.
    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>
    8d906d18