From 764ff429ac913567910e4acb1da98502f246754a Mon Sep 17 00:00:00 2001
From: Dmitry Shkurko <Dmitry.V.Shkurko@intel.com>
Date: Wed, 28 Aug 2013 19:33:24 +0700
Subject: Avoid integer overflow while calculating max values

BZ: 134249

The behavior is undefined in the case of signed integer overflow
for enum and fixed point parameter types.

Modify the behavior to handle correctly the signed integers.

Change-Id: Idbd0798a39f826853ae1afcd05cebd897675b9a8
Signed-off-by: Dmitry Shkurko <Dmitry.V.Shkurko@intel.com>
---
 parameter/EnumParameterType.cpp       |  2 +-
 parameter/FixedPointParameterType.cpp |  4 +---
 parameter/ParameterType.h             | 10 ++++++++++
 3 files changed, 12 insertions(+), 4 deletions(-)

(limited to 'parameter')

diff --git a/parameter/EnumParameterType.cpp b/parameter/EnumParameterType.cpp
index dcdbfaa..145e556 100644
--- a/parameter/EnumParameterType.cpp
+++ b/parameter/EnumParameterType.cpp
@@ -154,7 +154,7 @@ bool CEnumParameterType::toBlackboard(const string& strValue, uint32_t& uiValue,
 bool CEnumParameterType::checkValueAgainstRange(const string& strValue, int64_t value, CParameterAccessContext& parameterAccessContext, bool bHexaValue, bool bConversionSucceeded) const
 {
     // Enums are always signed, it means we have one less util bit
-    int64_t maxValue = (1 << (getSize() * 8 - 1)) - 1;
+    int64_t maxValue = getMaxValue<uint64_t>();
     int64_t minValue = -maxValue - 1;
 
     if (!bConversionSucceeded || value < minValue || value > maxValue) {
diff --git a/parameter/FixedPointParameterType.cpp b/parameter/FixedPointParameterType.cpp
index 3c9e20f..2b97f58 100644
--- a/parameter/FixedPointParameterType.cpp
+++ b/parameter/FixedPointParameterType.cpp
@@ -271,8 +271,6 @@ void CFixedPointParameterType::getRange(double& dMin, double& dMax) const
 // Out of range error
 string CFixedPointParameterType::getOutOfRangeError(const string& strValue, bool bRawValueSpace, bool bHexaValue) const
 {
-
-
     ostringstream strStream;
 
     strStream << "Value " << strValue << " standing out of admitted ";
@@ -288,7 +286,7 @@ string CFixedPointParameterType::getOutOfRangeError(const string& strValue, bool
     } else {
 
         // Min/Max computation
-        int32_t iMax = (1L << (getSize() * 8 - 1)) - 1;
+        int32_t iMax = getMaxValue<uint32_t>();
         int32_t iMin = -iMax - 1;
 
         strStream << "raw range [";
diff --git a/parameter/ParameterType.h b/parameter/ParameterType.h
index d83dbce..ed30ac3 100644
--- a/parameter/ParameterType.h
+++ b/parameter/ParameterType.h
@@ -25,6 +25,7 @@
 #pragma once
 
 #include <stdint.h>
+#include <limits>
 
 #include "TypeElement.h"
 
@@ -87,6 +88,15 @@ protected:
     // Remove all bits set outside available range
     uint32_t makeEncodable(uint32_t uiData) const;
 
+    /** Compute max value according to the parameter type */
+    template <typename type>
+    type getMaxValue() const
+    {
+        return getSize() < sizeof(type) ?
+                    (static_cast<type>(1) << (getSize() * numeric_limits<unsigned char>::digits - 1)) - 1 :
+                    numeric_limits<type>::max();
+    }
+
 private:
     // Instantiation
     virtual CInstanceConfigurableElement* doInstantiate() const;
-- 
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