From 5f6de83981187a41e296e7a7fa95ce3869f1b9ac Mon Sep 17 00:00:00 2001
From: Seth Hillbrand <seth@kipro-pcb.com>
Date: Sat, 1 Oct 2022 11:29:34 -0700
Subject: [PATCH] Ensure that token size is large enough

Input tokens can be arbitrary, so output needs to keep pace

Fixes https://gitlab.com/kicad/code/kicad/issues/12555

(cherry picked from commit 19378675f1ced79951d18e865b67c50cb5d09f75)
---
 common/libeval/numeric_evaluator.cpp | 9 ++++-----
 include/libeval/numeric_evaluator.h  | 7 +++++--
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/common/libeval/numeric_evaluator.cpp b/common/libeval/numeric_evaluator.cpp
index 8e81bcdde4..db63105321 100644
--- a/common/libeval/numeric_evaluator.cpp
+++ b/common/libeval/numeric_evaluator.cpp
@@ -77,7 +77,7 @@ NUMERIC_EVALUATOR::~NUMERIC_EVALUATOR()
 
 void NUMERIC_EVALUATOR::Clear()
 {
-    free( m_token.token );
+    delete[] m_token.token;
     m_token.token = nullptr;
     m_token.input = nullptr;
     m_parseError = true;
@@ -103,7 +103,7 @@ void NUMERIC_EVALUATOR::parseSetResult( double val )
     {
         // Naively printing this with %g produces "nan" on some platforms
         // and "-nan(ind)" on others (e.g. MSVC). So force a "standard" string.
-        snprintf( m_token.token, m_token.OutLen, "%s", "NaN" );
+        snprintf( m_token.token, m_token.outputLen, "%s", "NaN" );
     }
     else
     {
@@ -159,12 +159,11 @@ void NUMERIC_EVALUATOR::newString( const wxString& aString )
     Clear();
 
     m_originalText = aString;
-
-    m_token.token = reinterpret_cast<decltype( m_token.token )>( malloc( TokenStat::OutLen + 1 ) );
-    strcpy( m_token.token, "0" );
     m_token.inputLen = aString.length();
+    m_token.outputLen = std::max<std::size_t>( 64, m_token.inputLen + 1 );
     m_token.pos = 0;
     m_token.input = aString.mb_str();
+    m_token.token = new char[m_token.outputLen]();
 
     m_parseFinished = false;
 }
diff --git a/include/libeval/numeric_evaluator.h b/include/libeval/numeric_evaluator.h
index bf2a044f9d..91bac4a4a6 100644
--- a/include/libeval/numeric_evaluator.h
+++ b/include/libeval/numeric_evaluator.h
@@ -159,11 +159,14 @@ private:
     /* Token state for input string. */
     struct TokenStat
     {
-        enum { OutLen = 32 };
-        TokenStat() : input( nullptr ), token( nullptr ), inputLen( 0 ), pos( 0 ) { /* empty */ }
+        TokenStat() :
+            input( nullptr ), token( nullptr ), inputLen( 0 ), outputLen( 0 ), pos( 0 )
+            { /* empty */ }
+
         const char* input;      // current input string ("var=4")
         char*       token;      // output token ("var", type:VAR; "4", type:VALUE)
         size_t      inputLen;   // strlen(input)
+        size_t      outputLen;  // At least 64, up to input length
         size_t      pos;        // current index
     }
             m_token;