From e9ad2e5627880d2f2187024414aaf8ab61adf219 Mon Sep 17 00:00:00 2001
From: MassimilianoPinto <massimiliano.pinto@mariadb.com>
Date: Tue, 18 Jul 2017 10:42:23 +0200
Subject: [PATCH] Masking filter: added new obfuscation routine

Masking filter: added new obfuscation routine
---
 server/modules/filter/masking/maskingrules.cc | 43 ++++++-------------
 1 file changed, 12 insertions(+), 31 deletions(-)

diff --git a/server/modules/filter/masking/maskingrules.cc b/server/modules/filter/masking/maskingrules.cc
index f866e5832..d51bc3329 100644
--- a/server/modules/filter/masking/maskingrules.cc
+++ b/server/modules/filter/masking/maskingrules.cc
@@ -1102,32 +1102,6 @@ bool MaskingRules::Rule::matches(const ComQueryResponse::ColumnDef& column_def,
     return match;
 }
 
-/**
- * Basic obfuscation routine
- *
- * @param c    The bye to obfuscate
- *
- * @return     The obfuscated byte
- */
-static inline char maxscale_basic_obfuscation(const char c)
-{
-    if (c >= 'a' && c <= 'z')
-    {
-        return (c - 'a' + 13) % 26 + 'a';
-    }
-    else if (c >= 'A' && c <= 'Z')
-    {
-        return (c - 'A' + 13) % 26 + 'A';
-    }
-    else
-    {
-        char d = c + 32;
-        d = d > 127 ? 127 : d;
-        return d;
-    }
-    return c;
-}
-
 /**
  * Fills a buffer with a fill string
  *
@@ -1217,11 +1191,18 @@ void MaskingRules::MatchRule::rewrite(LEncString& s) const
 
 void MaskingRules::ObfuscateRule::rewrite(LEncString& s) const
 {
-    // Basic Obfuscation routine
-    std::transform(s.begin(),
-                   s.end(),
-                   s.begin(),
-                   maxscale_basic_obfuscation);
+    size_t i_len = s.length();
+    LEncString::iterator i = s.begin();
+    size_t c = *i + i_len;
+
+    for (LEncString::iterator i = s.begin(); i <= s.end(); i++)
+    {
+      // ASCII 32 is first printable char
+      unsigned char d = abs((char)(*i ^ c)) + 32;
+      c += d << 3;
+      // ASCII 126 is last printable char
+      *i = d <= 126 ? d : 126;
+    }
 }
 
 void MaskingRules::ReplaceRule::rewrite(LEncString& s) const