From 2689c727e7a99841e1d3f13e3a5a5fe62853e803 Mon Sep 17 00:00:00 2001
From: terrafrost <terrafrost@gmail.com>
Date: Wed, 1 May 2024 15:12:04 -0500
Subject: [PATCH] BigInteger: EvalBarrett / Barrett could sometimes slow to a
 crawl

---
 .../Engines/BCMath/Reductions/Barrett.php     |  2 +-
 .../Engines/PHP/Reductions/Barrett.php        |  2 +-
 .../Engines/PHP/Reductions/EvalBarrett.php    |  2 +-
 tests/Unit/Crypt/RSA/LoadKeyTest.php          | 21 +++++++++++++++++++
 4 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/phpseclib/Math/BigInteger/Engines/BCMath/Reductions/Barrett.php b/phpseclib/Math/BigInteger/Engines/BCMath/Reductions/Barrett.php
index 0fb7eaeb..ec1d5caa 100644
--- a/phpseclib/Math/BigInteger/Engines/BCMath/Reductions/Barrett.php
+++ b/phpseclib/Math/BigInteger/Engines/BCMath/Reductions/Barrett.php
@@ -66,7 +66,7 @@ abstract class Barrett extends Base
 
         $m_length = strlen($m);
 
-        if (strlen($n) > 2 * $m_length) {
+        if (strlen($n) >= 2 * $m_length) {
             return bcmod($n, $m);
         }
 
diff --git a/phpseclib/Math/BigInteger/Engines/PHP/Reductions/Barrett.php b/phpseclib/Math/BigInteger/Engines/PHP/Reductions/Barrett.php
index 3518d76f..84937419 100644
--- a/phpseclib/Math/BigInteger/Engines/PHP/Reductions/Barrett.php
+++ b/phpseclib/Math/BigInteger/Engines/PHP/Reductions/Barrett.php
@@ -56,7 +56,7 @@ abstract class Barrett extends Base
         $m_length = count($m);
 
         // if (self::compareHelper($n, $static::square($m)) >= 0) {
-        if (count($n) > 2 * $m_length) {
+        if (count($n) >= 2 * $m_length) {
             $lhs = new $class();
             $rhs = new $class();
             $lhs->value = $n;
diff --git a/phpseclib/Math/BigInteger/Engines/PHP/Reductions/EvalBarrett.php b/phpseclib/Math/BigInteger/Engines/PHP/Reductions/EvalBarrett.php
index 2f943317..2cf69f2e 100644
--- a/phpseclib/Math/BigInteger/Engines/PHP/Reductions/EvalBarrett.php
+++ b/phpseclib/Math/BigInteger/Engines/PHP/Reductions/EvalBarrett.php
@@ -100,7 +100,7 @@ abstract class EvalBarrett extends Base
         $cutoff = count($m) + (count($m) >> 1);
 
         $code = '
-            if (count($n) > ' . (2 * count($m)) . ') {
+            if (count($n) >= ' . (2 * count($m)) . ') {
                 $lhs = new ' . $class . '();
                 $rhs = new ' . $class . '();
                 $lhs->value = $n;
diff --git a/tests/Unit/Crypt/RSA/LoadKeyTest.php b/tests/Unit/Crypt/RSA/LoadKeyTest.php
index 3ec7c9e6..59a1fc10 100644
--- a/tests/Unit/Crypt/RSA/LoadKeyTest.php
+++ b/tests/Unit/Crypt/RSA/LoadKeyTest.php
@@ -1421,4 +1421,25 @@ vtpiPBM=
 
         $this->pkcs8tester($key, $pass);
     }
+
+    /**
+     * @group github1994
+     */
+    public function testCloseNumbers()
+    {
+        $rsa = PublicKeyLoader::load([
+            // Modulus
+            'n' => new BigInteger('5BDD6AFB1E1AFB50D1B2989F70B549B8D44AE3712B444F2C5D862C46C99526E998B79BF0B4F1461524E39D263F3130B9E08F3B17C2070785EFB0EDEC1E75C6C2B8185FA9596886D5DAF8B68E92FCF5F1B33E7CD772845555B086D2A2466B6398A04DFE1C727BB020g1ED2BF3F03D2826F89616D0846C18B1D87064616FAD394462', 16),
+
+            // Exponent
+            'e' => new BigInteger('6FE4F5D0AFCC16E8A5CC68955D4EF28255A546D06F34DD103540B9A7D202AEC96353072DB65D9C360E9030F413971142EE6A28974767CCF3ABFA4E7ADDAEAD81D3F8AE5FF1B8241CA9EF51C10941FFFA74482A636CBD909D29CF7A0346653D3C286EA1F392F4968AEF1489EC4B4BCEA4F248F3931B1C9BE2808DBD33B049731A', 16)
+        ])
+            ->withPadding(RSA::SIGNATURE_PKCS1)
+            ->withHash('md5')
+            ->asPrivateKey();
+
+        $sig = bin2hex($rsa->sign('toto'));
+        $expected = '4370b3fd5dd318c0c3be8989574fbf4ededc805c6f225ada84f8d882d327b7b300f899878204ff99efdf03b17c26518b8941d602abd16dbdac637c5ae61814cb689da266fe07bc978d417fe6742f650bc35ee79dd2431912fc19e36012e61fcb7cdfd506ca3c5b80';
+        $this->assertSame($expected, $sig);
+    }
 }