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43:12 REcon English 2011

Checkpoint-Restart: Proprietary Hardware and the "Spiderweb API"

This summary describes a package to transparently checkpoint and restart applications which run over Infiniband. Infiniband is rapidly growing as a high-speed interconnect, even appearing on departmental clusters. The current work grew out of the needs of high performance computing. As of November, 2010, 43% of the TOP500 supercomputers run Infiniband. However, the ability to checkpoint immediately provides access to a poor man's reversible debugger. Using our DMTCP (Distributed MultiThreaded CheckPointing), we can already checkpoint a GDB session today: if we have executed 100 commands since the last checkpoint, we can undo the last instruction by restarting the checkpoint and going forward 99 commands. Since many apps access Infiniband through MPI (Message Passing Interface) instead of direct communication with Infiniband, we also integrated DMTCP into the OpenMPI dialect so as to transparently debug an MPI-based application. Infiniband's primary mechanism to provide fast latency is Remote Direct Memory Access (RDMA). One host can directly read or write the RAM of another host, without intervention by the CPU or software. The previously mentioned debugger logs commands and allows you to go back in history, through restarting and re-executing. It means that we can now conceive of time as a spatial dimension instead of a temporal dimension. So we can write a binary search program acting over the process's lifetime. This is illustrated in a later section. In a complex Infiniband computation, memory is written to and read from with latencies of less than 1 microsecond. Assert statements or breakpoints would change the course of execution because the program no longer runs at native speed.
  • Published: 2011
  • Publisher: REcon
  • Language: English
42:34 REcon English 2011

Hardware Stuff for Software People

This talk will be an introduction to doing "hardware stuff" stuff, for people accustomed to plying their trade against software. I will discuss how to build tools (and use existing tools) to sniff/spy on a variety of hardware communications channels from UART Serial (the kind in your computer) to the very ubiquitous SPI/I2C serial busses used in virtual everything (from EEPROM in your portable DVD player to the HDMI/VGA cables between your computer and monitor). I will demonstrate how these simple hardware taps can be used to begin reverse engineering, spoofing, and fuzzing in places where (as a software person) you might not have previously felt comfortable. I will be bringing along a number of custom hardware and software tools (used specifically for these purposes) as well as a mock lab environment for demonstrations. Other than these practical skills, I am new to this "hardware stuff" so please don't expect a "embedded-JTag-SCADA-mobile" buzzword soliloquy. I'll just be sharing some stories and showing some neat hardware and software I've recently found useful.
  • Published: 2011
  • Publisher: REcon
  • Language: English
1:14:39 REcon English 2011

Internet Filtering

Many countries in the world perform extensive network surveillance, filtering in the form of website blocking or protocol specific censorship; recently many networked authoritarian events in the Middle East/North Africa and across most of the world have come to light. During some specific political uprisings came increased invasive filtering events. I've run a series of tests in many of these countries, during these events with the specific purpose of identifying specific hardware and software in use. Some of the technical details are not novel but their application certainly makes a positive contribution. In some contexts, it's possible to identify specific network links that flag, drop, or inject data at the country level. I intend to show real world data such as block pages, network traces, scans of filters, interesting network blocks and I will discuss techniques for gathering useful data.
  • Published: 2011
  • Publisher: REcon
  • Language: English
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