From 54211caa2e0e5163aefef390daf88a971367a702 Mon Sep 17 00:00:00 2001 From: Glenn Strauss Date: Tue, 4 Oct 2022 17:09:24 -0400 Subject: [PATCH 6/7] dpp_pkex: EC point mul w/ value < prime crypto_ec_point_mul() with mbedtls requires point be multiplied by a multiplicand with value < prime Signed-off-by: Glenn Strauss --- src/common/dpp_crypto.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/src/common/dpp_crypto.c +++ b/src/common/dpp_crypto.c @@ -1588,7 +1588,9 @@ dpp_pkex_derive_Qr(const struct dpp_curv Pr = crypto_ec_key_get_public_key(Pr_key); Qr = crypto_ec_point_init(ec); hash_bn = crypto_bignum_init_set(hash, curve->hash_len); - if (!Pr || !Qr || !hash_bn || crypto_ec_point_mul(ec, Pr, hash_bn, Qr)) + if (!Pr || !Qr || !hash_bn || + crypto_bignum_mod(hash_bn, crypto_ec_get_prime(ec), hash_bn) || + crypto_ec_point_mul(ec, Pr, hash_bn, Qr)) goto fail; if (crypto_ec_point_is_at_infinity(ec, Qr)) {