lkml.org 
[lkml]   [2024]   [Apr]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v3 1/2] crypto: ecdh - Pass private key in proper byte order to check valid key
    Date
    ecc_is_key_valid expects a key with the most significant digit in the last
    entry of the digit array. Currently ecdh_set_secret passes a reversed key
    to ecc_is_key_valid that then passes the rather simple test checking
    whether the private key is in range [2, n-3]. For all current ecdh-
    supported curves (NIST P192/256/384) the 'n' parameter is a rather large
    number, therefore easily passing this test.

    Throughout the ecdh and ecc codebase the variable 'priv' is used for a
    private_key holding the bytes in proper byte order. Therefore, introduce
    priv in ecdh_set_secret and copy the bytes from ctx->private_key into
    priv in proper byte order by using ecc_swap_digits. Pass priv to
    ecc_is_valid_key.

    Cc: Ard Biesheuvel <ardb@kernel.org>
    Cc: Salvatore Benedetto <salvatore.benedetto@intel.com>
    Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
    Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
    ---
    crypto/ecdh.c | 11 ++++++++---
    1 file changed, 8 insertions(+), 3 deletions(-)

    diff --git a/crypto/ecdh.c b/crypto/ecdh.c
    index 3049f147e011..c02c9a2b9682 100644
    --- a/crypto/ecdh.c
    +++ b/crypto/ecdh.c
    @@ -27,7 +27,9 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
    unsigned int len)
    {
    struct ecdh_ctx *ctx = ecdh_get_ctx(tfm);
    + u64 priv[ECC_MAX_DIGITS];
    struct ecdh params;
    + int ret = 0;

    if (crypto_ecdh_decode_key(buf, len, &params) < 0 ||
    params.key_size > sizeof(u64) * ctx->ndigits)
    @@ -40,13 +42,16 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf,
    ctx->private_key);

    memcpy(ctx->private_key, params.key, params.key_size);
    + ecc_swap_digits(ctx->private_key, priv, ctx->ndigits);

    if (ecc_is_key_valid(ctx->curve_id, ctx->ndigits,
    - ctx->private_key, params.key_size) < 0) {
    + priv, params.key_size) < 0) {
    memzero_explicit(ctx->private_key, params.key_size);
    - return -EINVAL;
    + ret = -EINVAL;
    }
    - return 0;
    + memzero_explicit(priv, sizeof(priv));
    +
    + return ret;
    }

    static int ecdh_compute_value(struct kpp_request *req)
    --
    2.43.0

    \
     
     \ /
      Last update: 2024-05-27 16:46    [W:5.485 / U:0.032 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site