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    Subject[PATCH 4.16 34/68] sunrpc: remove incorrect HMAC request initialization
    Date
    4.16-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Eric Biggers <ebiggers@google.com>

    commit f3aefb6a7066e24bfea7fcf1b07907576de69d63 upstream.

    make_checksum_hmac_md5() is allocating an HMAC transform and doing
    crypto API calls in the following order:

    crypto_ahash_init()
    crypto_ahash_setkey()
    crypto_ahash_digest()

    This is wrong because it makes no sense to init() the request before a
    key has been set, given that the initial state depends on the key. And
    digest() is short for init() + update() + final(), so in this case
    there's no need to explicitly call init() at all.

    Before commit 9fa68f620041 ("crypto: hash - prevent using keyed hashes
    without setting key") the extra init() had no real effect, at least for
    the software HMAC implementation. (There are also hardware drivers that
    implement HMAC-MD5, and it's not immediately obvious how gracefully they
    handle init() before setkey().) But now the crypto API detects this
    incorrect initialization and returns -ENOKEY. This is breaking NFS
    mounts in some cases.

    Fix it by removing the incorrect call to crypto_ahash_init().

    Reported-by: Michael Young <m.a.young@durham.ac.uk>
    Fixes: 9fa68f620041 ("crypto: hash - prevent using keyed hashes without setting key")
    Fixes: fffdaef2eb4a ("gss_krb5: Add support for rc4-hmac encryption")
    Cc: stable@vger.kernel.org
    Signed-off-by: Eric Biggers <ebiggers@google.com>
    Signed-off-by: J. Bruce Fields <bfields@redhat.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    net/sunrpc/auth_gss/gss_krb5_crypto.c | 3 ---
    1 file changed, 3 deletions(-)

    --- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
    +++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
    @@ -237,9 +237,6 @@ make_checksum_hmac_md5(struct krb5_ctx *

    ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);

    - err = crypto_ahash_init(req);
    - if (err)
    - goto out;
    err = crypto_ahash_setkey(hmac_md5, cksumkey, kctx->gk5e->keylength);
    if (err)
    goto out;

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