1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking Benchmarking Platform
Phoromatic Test Orchestration

Linux Kernel Works To Make Better Random Reseeding

Hardware

Published on 15 December 2013 09:05 AM EST
Written by Michael Larabel in Hardware
1 Comment

While /dev/random was made faster and more random in Linux 3.13, in light of the NSA controversies and that Intel/VIA hardware encryption and random generators may not even be trustworthy, there's been a rework in how reseeding happens for the Linux kernel's random component.

Greg Price sent out a patch-set on Saturday that changes how re-seeing the non-blocking pool happens, which supplies /dev/urandom and the kernel's internal randomness needs.

Greg wrote, "The most important change is to make sure that the input entropy always comes in large chunks, what we've called a 'catastrophic reseed', rather than a few bits at a time with the possibility of producing output after every few bits. If we do the latter, we risk that an attacker could see the output (e.g. by watching us use it, or by constantly reading /dev/urandom), and then brute-force the few bits of entropy before each output in turn...After the whole series, our behavior at boot is to seed with whatever we have when first asked for random bytes, then hold out for seeds of doubling size until we reach the target (by default 512b estimated.) Until we first reach the minimum reseed size (128b by default), all input collected is exclusively for the nonblocking pool and /dev/random readers must wait."

More details on this random re-seeding rework for the Linux kernel can be found on the kernel mailing list and could appear in the Linux 3.14 kernel.

About The Author
Michael Larabel is the principal author of Phoronix.com and founded the web-site in 2004 with a focus on enriching the Linux hardware experience and being the largest web-site devoted to Linux hardware reviews, particularly for products relevant to Linux gamers and enthusiasts but also commonly reviewing servers/workstations and embedded Linux devices. Michael has written more than 10,000 articles covering the state of Linux hardware support, Linux performance, graphics hardware drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated testing software. He can be followed via and or contacted via .
Latest Articles & Reviews
  1. GLAMOR + RadeonSI 2D Acceleration Is Quite Good For Open-Source AMD 2D Performance
  2. AMD Radeon R9 290 OpenGL On Ubuntu 15.04: Catalyst vs. RadeonSI Gallium3D
  3. Ubuntu 15.04 Offers Faster OpenGL For AMD Radeon GPUs On Open-Source
  4. Ubuntu 15.04 Brings Some Graphics Performance Improvements For Intel Haswell
  5. Sub-$20 802.11n USB WiFi Adapter That's Linux Friendly
  6. The Lenovo T450s Is Working Beautifully With Linux
Latest Linux News
  1. A Lot Of Improvements Are Coming For Mir 0.13, Including Work Towards Libinput
  2. Mobile Optimizations Coming For Phoronix
  3. Wayland 1.8 Alpha Release Delayed
  4. Godot Game Engine 1.1 Up To RC State
  5. ATI Rage128 Driver Now Has RandR Support
  6. Microsoft's Visual C++ Team Is Improving Clang For Windows
  7. Kodi 15.0 Beta 1 Released
  8. Lucid Sleep Support Is Being Worked On For The Upstream Linux Kernel
  9. Improvements On The Way For GNOME's Nautilus File Manager
  10. Wine 1.7.42 Implements More Of Direct2D
Most Viewed News This Week
  1. It Doesn't Look Like KDBUS Will Make It For Linux 4.1
  2. Trying Out Microsoft Visual Studio Code On Linux
  3. The Many Features Of The Linux 4.1 Kernel
  4. Microsoft Releases New Code IDE For Linux!
  5. Linux 4.1-rc1 Kernel Released, Packs In Several New Features
  6. GCC 4.9.2 vs. GCC 5 Benchmarks On An Intel Xeon Haswell
  7. QEMU 2.3 Officially Released
  8. Debian 9.0 Is Codenamed Stretch