diff options
| -rw-r--r-- | src/crypto/elliptic/p256.go | 2 | ||||
| -rw-r--r-- | src/crypto/elliptic/p256_test.go | 14 |
2 files changed, 15 insertions, 1 deletions
diff --git a/src/crypto/elliptic/p256.go b/src/crypto/elliptic/p256.go index b2b12c8f13..da5283735c 100644 --- a/src/crypto/elliptic/p256.go +++ b/src/crypto/elliptic/p256.go @@ -52,7 +52,7 @@ func p256GetScalar(out *[32]byte, in []byte) { n := new(big.Int).SetBytes(in) var scalarBytes []byte - if n.Cmp(p256Params.N) >= 0 { + if n.Cmp(p256Params.N) >= 0 || len(in) > len(out) { n.Mod(n, p256Params.N) scalarBytes = n.Bytes() } else { diff --git a/src/crypto/elliptic/p256_test.go b/src/crypto/elliptic/p256_test.go index 1435f5e1a5..694186df81 100644 --- a/src/crypto/elliptic/p256_test.go +++ b/src/crypto/elliptic/p256_test.go @@ -153,3 +153,17 @@ func TestP256CombinedMult(t *testing.T) { t.Errorf("1×G + (-1)×G = (%d, %d), should be ∞", x, y) } } + +func TestIssue52075(t *testing.T) { + Gx, Gy := P256().Params().Gx, P256().Params().Gy + scalar := make([]byte, 33) + scalar[32] = 1 + x, y := P256().ScalarBaseMult(scalar) + if x.Cmp(Gx) != 0 || y.Cmp(Gy) != 0 { + t.Errorf("unexpected output (%v,%v)", x, y) + } + x, y = P256().ScalarMult(Gx, Gy, scalar) + if x.Cmp(Gx) != 0 || y.Cmp(Gy) != 0 { + t.Errorf("unexpected output (%v,%v)", x, y) + } +} |