0000964: Integer saturation in chistogram.cc when when input value range is very large

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0000964

OMNeT++

simulation kernel

public

2016-07-15 08:57

Reporter

pfefferk

Assigned To

Priority

low

Severity

minor

Reproducibility

always

Status

new

Resolution

open

Platform

x86_64

Ubuntu

OS Version

16.04 (xenial)

Product Version

5.0

Target Version

Fixed in Version

Summary

0000964: Integer saturation in chistogram.cc when when input value range is very large

Description

When working with a custom PER calculation model, I found a bug within chistogram::setupRangeInteger (chistogram.cc line 333). The calculated PER value would exceed 1.0 by far, which would cause an integer overflow when calculating cellSize for non-fixed ranges. With a maximum recorded value of 2,32e+291 (long)ceil(rangeMax - rangeMin/200.0) would result in a negative value for numCels (0x8000000000000000), since (long) and not (unsigned long) is used.
This causes an error in cHistogram::transform() (chistogram.cc line 129):
cellv = new unsigned[numCells];
which results in: std::bad_array_new_length.

Changing the lines to cast to unsigned long instead, does not generate a negative value for numCells, but still results in std::bad_array_new_length. It seems as in this case some other limit is active.

It seems that a maximum or minimum check before the creation of the new array should be introduced avoiding the array creation failure.

Steps To Reproduce

- Use histogram in integer mode
- record very large value

Issue History
Date Modified	Username	Field	Change
2016-07-15 08:57	pfefferk	New Issue

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