ecc_is_key_valid expects a key with the most significant digit in the last entry of the digit array. Currently a reverse key is passed 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. Fix the format of the digit by using ecc_digits_from_bytes to create a temporary private key and pass it to the test function. Keep the swapped key in ctx->private_key. Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx> --- crypto/ecdh.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/crypto/ecdh.c b/crypto/ecdh.c index 80afee3234fb..f187365db7b6 100644 --- a/crypto/ecdh.c +++ b/crypto/ecdh.c @@ -27,6 +27,8 @@ 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]; + unsigned int nbytes; struct ecdh params; if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0 || @@ -37,10 +39,13 @@ static int ecdh_set_secret(struct crypto_kpp *tfm, const void *buf, return ecc_gen_privkey(ctx->curve_id, ctx->ndigits, ctx->private_key); - memcpy(ctx->private_key, params.key, params.key_size); + nbytes = ctx->ndigits << ECC_DIGITS_TO_BYTES_SHIFT; + + memcpy(ctx->private_key, params.key, nbytes); + 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; } -- 2.43.0