nil-check inspired dsa.Verify issue: github.com/golang/go/issues/34960

ecies · Oct 28, 2019 · 1e3405e · 1e3405e
1 parent 5a940da
commit 1e3405e
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/publickey.go b/publickey.go
@@ -58,7 +58,9 @@ func NewPublicKeyFromBytes(b []byte) (*PublicKey, error) {
 		x3b.Mul(&x3b, x)
 		x3b.Add(&x3b, curve.Params().B)
 		x3b.Mod(&x3b, curve.Params().P)
-		y.ModSqrt(&x3b, curve.Params().P)
+		if z := y.ModSqrt(&x3b, curve.Params().P); z == nil {
+			return nil, fmt.Errorf("cannot parse public key")
+		}
 
 		if y.Bit(0) != ybit {
 			y.Sub(curve.Params().P, &y)