From b9746258324c31ea09df5a0b8e4441a376202268 Mon Sep 17 00:00:00 2001
From: Ben Woosley <ben.woosley@gmail.com>
Date: Wed, 2 May 2018 20:16:44 -0400
Subject: [PATCH] Don't mutate the elliptic curve prototype with get* additions

Point's prototype is set to the prototype of ec('secp256k1').curve.point(), which means mutation to it is shared across users of 'elliptic' via the in-memory representation of those objects.

This is not generally a problem, for example, with `validate` it's a simple set, so the greatest risk is that it will be directly overwritten.

But in the case of `getX` and `getY`, both methods are overwritten with others that depend on the prior implementation as stored in `_get*`. If this happens twice, then the implementation of `_getX` is replaced with something that depends on a call to `_getX`, and the callers is stuck in an infinite loop.
---
 bitcore-lib.js      | 8 ++++----
 lib/crypto/point.js | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/bitcore-lib.js b/bitcore-lib.js
index 3014204b9..452b3a67e 100644
--- a/bitcore-lib.js
+++ b/bitcore-lib.js
@@ -2084,7 +2084,7 @@ Point.getN = function getN() {
   return new BN(ec.curve.n.toArray());
 };
 
-Point.prototype._getX = Point.prototype.getX;
+Point._getX = Point.prototype.getX;
 
 /**
  *
@@ -2092,11 +2092,11 @@ Point.prototype._getX = Point.prototype.getX;
  *
  * @returns {BN} A BN instance of the X coordinate
  */
-Point.prototype.getX = function getX() {
+Point.getX = function getX() {
   return new BN(this._getX().toArray());
 };
 
-Point.prototype._getY = Point.prototype.getY;
+Point._getY = Point.prototype.getY;
 
 /**
  *
@@ -2104,7 +2104,7 @@ Point.prototype._getY = Point.prototype.getY;
  *
  * @returns {BN} A BN instance of the Y coordinate
  */
-Point.prototype.getY = function getY() {
+Point.getY = function getY() {
   return new BN(this._getY().toArray());
 };
 
diff --git a/lib/crypto/point.js b/lib/crypto/point.js
index 6046ed361..23b338eef 100644
--- a/lib/crypto/point.js
+++ b/lib/crypto/point.js
@@ -73,7 +73,7 @@ Point.getN = function getN() {
   return new BN(ec.curve.n.toArray());
 };
 
-Point.prototype._getX = Point.prototype.getX;
+Point._getX = Point.prototype.getX;
 
 /**
  *
@@ -81,11 +81,11 @@ Point.prototype._getX = Point.prototype.getX;
  *
  * @returns {BN} A BN instance of the X coordinate
  */
-Point.prototype.getX = function getX() {
+Point.getX = function getX() {
   return new BN(this._getX().toArray());
 };
 
-Point.prototype._getY = Point.prototype.getY;
+Point._getY = Point.prototype.getY;
 
 /**
  *
@@ -93,7 +93,7 @@ Point.prototype._getY = Point.prototype.getY;
  *
  * @returns {BN} A BN instance of the Y coordinate
  */
-Point.prototype.getY = function getY() {
+Point.getY = function getY() {
   return new BN(this._getY().toArray());
 };