Diogo A. B. Fernandes
Mário M. Freire
ABSTRACT
Virtualization technology provided cloud computing with the means to rapidly disseminate throughout the industry and achieve the utility computing long-envisioned era. Efforts on this research area have been focused on assuring isolation between co-resident virtual machines to avoid escaping the sandbox, but less attention has been given to the implications virtualization may pose to the efficiency and quality of random number generation on guests. On Linux distributions, the good provisioning of entropy gathered by the kernel is crucial for the functioning of its random number generator. However, entropy sources may be scarce on virtual machines due to the abstraction implied by the virtualization layer. As a consequence, both the generation speed and the quality of random numbers might drop when compared to hosts. This paper looks into this issue and analyzes the outputs of the /dev/random interface of the Linux kernel on virtual machines. With a well-know statistical library it is shown that the outputs are of high quality and are independently generated, even though they are produced on a slower basis.
References
- D. A. B. Fernandes, L. F. B. Soares, J. V. Gomes, M. M. Freire, and P. R. M. Inácio, "Security Issues in Cloud Environments -- A Survey," International Journal of Information Security, pp. 1-62, 2013, accepted for publication.Google Scholar
- T. Ristenpart, E. Tromer, H. Shacham, and S. Savage, "Hey, You, Get Off of My Cloud: Exploring Information Leakage in Third-Party Compute Clouds," in Proc. of the 16th ACM Conf. on Computer and Communications Security. New York, NY, USA: ACM, Nov. 2009, pp. 199-212. Google ScholarDigital Library
- Z. Gutterman, B. Pinkas, and T. Reinman, "Analysis of the Linux Random Number Generator," in Proc. of the IEEE Symp. on Security and Privacy. Oakland, CA, USA: IEEE Computer Society, May 2006, pp. 371-385. Google ScholarDigital Library
- P. Lacharme, A. Röck, V. Strubel, and M. Videau, "The Linux Pseudorandom Number Generator Revisited," IACR Cryptology ePrint Archive, vol. 2012, p. 245, 2012.Google Scholar
- T. Ristenpart and S. Yilek, "When Good Randomness Goes Bad: Virtual Machine Reset Vulnerabilities and Hedging Deployed Cryptography," in Proc. of the Network and Distributed Security Symposium (NDSS). San Diego, CA, USA: The Internet Society, Feb.-Mar. 2010, pp. 1-18.Google Scholar
- N. Heninger, Z. Durumeric, E. Wustrow, and J. A. Halderman, "Mining Your Ps and Qs: Detection of Widespread Weak Keys in Network Devices," in Proc. of the 21st USENIX Security Symp. Bellevue, WA, USA: USENIX, Aug. 2012, pp. 205-220. Google ScholarDigital Library
- D. Kirkland, "Entropy (or rather the lack thereof) in OpenStack instances... and how to improve that," http://www.openstack.org/summit/san-diego-2012/openstack-summit-sessions/presentation/entropy-or-lack-thereof-in-openstack-instances, Oct. 2012, accessed Jul. 2013.Google Scholar
- A. Stamos, A. Becherer, and N. Wilcox, "Cloud Computing Security: Raining on the Trendy New Parade," Black Hat Conf., Jul. 2009.Google Scholar
- B. Kerrigan and Y. Chen, "A Study of Entropy Sources in Cloud Computers: Random Number Generation on Cloud Hosts," in Proc. of the 6th Int. Conf. on Mathematical Methods, Models and Architectures for Computer Network Security (MMM-ACNS). St. Petersburg, Russia: Springer-Verlag, Oct. 2012, pp. 286-298. Google ScholarDigital Library
- Amazon Discussion Forums, "Low Entropy on EC2 instances," https://forums.aws.amazon.com/thread.jspa? messageID=249079, May 2011, accessed Apr. 2013.Google Scholar
- VMware Community Forums, "Low /proc/sys/kernel/random/entropy_avail causes exim to stop sending mail," http://communities.vmware.com/message/530909, Aug. 2006, accessed May 2013.Google Scholar
- P. Patel, "Solution: FUTEX WAIT hangs Java on Linux / Ubuntu in vmware or virtual box," http://www.jroller.com/prpatel/entry/solution_futex_wait_hangs_java, Jan. 2010, accessed May 2013.Google Scholar
- Richard Simard, "TestU01 Website," http://www.iro. umontreal.ca/~simardr/testu01/tu01.html, accessed Jul. 2013.Google Scholar
Index Terms
Randomness in Virtual Machines
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