From efc498ca4caa340ac2fe11f2efee06c1a294501f Mon Sep 17 00:00:00 2001
From: David Hook <dgh@cryptoworkshop.com>
Date: Mon, 18 Dec 2023 14:41:35 +1100
Subject: [PATCH] added bounds check on f2m field size.

---
 core/src/main/java/org/bouncycastle/math/ec/ECCurve.java | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/core/src/main/java/org/bouncycastle/math/ec/ECCurve.java b/core/src/main/java/org/bouncycastle/math/ec/ECCurve.java
index 04bde03404..dec459d49e 100644
--- a/core/src/main/java/org/bouncycastle/math/ec/ECCurve.java
+++ b/core/src/main/java/org/bouncycastle/math/ec/ECCurve.java
@@ -998,6 +998,11 @@ protected ECFieldElement solveQuadraticEquation(ECFieldElement beta)
 
             int m = this.getFieldSize();
 
+            if (m > Properties.asInteger("org.bouncycastle.ec.max_f2m_field_size", 1142))  // twice 571
+            {
+                throw new IllegalStateException("field size out of range: " + m);
+            }
+            
             // For odd m, use the half-trace 
             if (0 != (m & 1))
             {