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Merge pull request #4074 from SparkiDev/ecdsa_dbl_table_point

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ECDSA FP ECC: fix corner case
This commit is contained in:
David Garske
2021-06-08 08:35:17 -07:00
committed by GitHub
parent 5586bc349c c69665b999
commit 61eae79f71
1 changed files with 12 additions and 1 deletions
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13
wolfcrypt/src/ecc.c
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@@ -5942,7 +5942,18 @@ int ecc_projective_add_point_safe(ecc_point* A, ecc_point* B, ecc_point* R,
if ((err == MP_OKAY) && mp_iszero(R->z)) { if ((err == MP_OKAY) && mp_iszero(R->z)) {
/* When all zero then should have done a double */ /* When all zero then should have done a double */
if (mp_iszero(R->x) && mp_iszero(R->y)) { if (mp_iszero(R->x) && mp_iszero(R->y)) {
err = ecc_projective_dbl_point(B, R, a, modulus, mp); if (mp_iszero(B->z)) {
err = wc_ecc_copy_point(B, R);
if (err == MP_OKAY) {
err = mp_montgomery_calc_normalization(R->z, modulus);
}
if (err == MP_OKAY) {
err = ecc_projective_dbl_point(R, R, a, modulus, mp);
}
}
else {
err = ecc_projective_dbl_point(B, R, a, modulus, mp);
}
} }
/* When only Z zero then result is infinity */ /* When only Z zero then result is infinity */
else { else {