4 ms·

I haven't been following any back-and-forth, but I'm a fan of exploit mitigation so I'll chime in and say to anyone browsing here that https://www.openbsd.org/p

I haven't been following any back-and-forth, but I'm a fan of exploit mitigation so I'll chime in and say to anyone browsing here that https://www.openbsd.org/papers/ru13-deraadt/mgp00001.html https://www.openbsd.org/papers/ru13-deraadt/mgp00001.html is an excellent explanation of them. (I was shocked when I just googled "exploit mitigation" and all I got back was infomercial articles by Symantec and Sophos etc. Scary. So for people browsing here and googling terms, dig deeper!) I think we need exploit mitigation _and_ process isolation _and_ the principle of least privilege. Fwiw, the twitter article mentions capabilities. Something I can pontificate about! I've been lucky enough to chew a _lot_ of cud with some GNOSIS/KeyKOS/caps luminaries etc. And we were still mega-fans of the Capability Object Model but _not_ believers in Capability-Based Addressing. When I did some design work with Norm Hardy on the Mill CPU I designed a temporal variant of the former that protected ... memory. OpenBSD is actually damn serious about the former. The twitter link is advocating the latter as a fix for something? I would love to chat with anyone who wants to convince me that Capability-Based Addressing _works_ or is workable. I know that others from KeyKOS etc moved more towards the caps addressing. Anyone want to read up on some of this stuff, I warmly recommend the papers and talks for CHERI, even though I'm not a fan of caps addressing.

anonymousDan 8y ago
What exactly do you mean by capability based addressing Vs capability object model? Is it the use of capabilities to grant access to particular chunks of memory? What do you see as the pros and cons?
- nickpsecurity 8y ago
  This free book is probably best place to start: http://www.cs.washington.edu/homes/levy/capabook/index.html http://www.cs.washington.edu/homes/levy/capabook/index.html The surviving, capability architecture is System/38 -> AS/400 -> IBM i. A side effect of better architecture is that they are also incredibly reliable. One person here described them as the tanks of their company's servers.
- willvarfar 8y ago
  The Object Capability Model https://en.wikipedia.org/wiki/Object-capability_model https://en.wikipedia.org/wiki/Object-capability_model is the general approach of tracking priviledges at a fine grain. Capability-based addressing https://en.wikipedia.org/wiki/Capability-based_addressing https://en.wikipedia.org/wiki/Capability-based_addressing is hardware that implements 'fat pointers' that point to ranges of memory so its not possible for a program to address memory it shouldn't. Basically, it forces programs to be 'memory safe' https://en.wikipedia.org/wiki/Memory_safety https://en.wikipedia.org/wiki/Memory_safety even if written in memory-unsafe languages such as C.
- sebcat 8y ago
  Reposting this from the other day: https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ Paper: https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/201406-isca2014-cheri.pdf https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/201406... "Motivated by contemporary security challenges, we reevaluate and refine capability-based addressing for the RISC era. We present CHERI, a hybrid capability model that extends the 64-bit MIPS ISA with byte-granularity memory protection."
grawlinson 8y ago
> I haven't been following any back-and-forth, but I'm a fan of exploit mitigation so I'll chime in and say to anyone browsing here that https://www.openbsd.org/papers/ru13-deraadt/mgp00001.html https://www.openbsd.org/papers/ru13-deraadt/mgp00001.html is an excellent explanation of them. Is it possible to get this resource on a single page? Having to click through each page just to read a sentence or two is quite cumbersome.
- notaplumber 8y ago
  There's a thumbnail index for MagicPoint slides: https://www.openbsd.org/papers/ru13-deraadt/index.html https://www.openbsd.org/papers/ru13-deraadt/index.html I also highly recommend checking OpenBSD's events page for additional slides/papers and videos. https://www.openbsd.org/events.html https://www.openbsd.org/events.html
- willvarfar 8y ago
  Its talk slides, but I personally find the slides easy to just read, even if you have to keep clicking for the next slide. A quick googling finds this https://events.yandex.com/lib/talks/103/ https://events.yandex.com/lib/talks/103/ which is, I think, Theo presenting the slides on part II.
- cpach 8y ago
  Would be neat with a keyboard shortcut in one’s browser that would go the the next page. (E.g. increase 00001 to 00002, etc.)

anonymousDan 8y ago

What exactly do you mean by capability based addressing Vs capability object model? Is it the use of capabilities to grant access to particular chunks of memory? What do you see as the pros and cons?

nickpsecurity 8y ago
This free book is probably best place to start: http://www.cs.washington.edu/homes/levy/capabook/index.html http://www.cs.washington.edu/homes/levy/capabook/index.html The surviving, capability architecture is System/38 -> AS/400 -> IBM i. A side effect of better architecture is that they are also incredibly reliable. One person here described them as the tanks of their company's servers.
willvarfar 8y ago
The Object Capability Model https://en.wikipedia.org/wiki/Object-capability_model https://en.wikipedia.org/wiki/Object-capability_model is the general approach of tracking priviledges at a fine grain. Capability-based addressing https://en.wikipedia.org/wiki/Capability-based_addressing https://en.wikipedia.org/wiki/Capability-based_addressing is hardware that implements 'fat pointers' that point to ranges of memory so its not possible for a program to address memory it shouldn't. Basically, it forces programs to be 'memory safe' https://en.wikipedia.org/wiki/Memory_safety https://en.wikipedia.org/wiki/Memory_safety even if written in memory-unsafe languages such as C.
sebcat 8y ago
Reposting this from the other day: https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ https://www.cl.cam.ac.uk/research/security/ctsrd/cheri/ Paper: https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/201406-isca2014-cheri.pdf https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/201406... "Motivated by contemporary security challenges, we reevaluate and refine capability-based addressing for the RISC era. We present CHERI, a hybrid capability model that extends the 64-bit MIPS ISA with byte-granularity memory protection."

grawlinson 8y ago

> I haven't been following any back-and-forth, but I'm a fan of exploit mitigation so I'll chime in and say to anyone browsing here that https://www.openbsd.org/papers/ru13-deraadt/mgp00001.html https://www.openbsd.org/papers/ru13-deraadt/mgp00001.html is an excellent explanation of them. Is it possible to get this resource on a single page? Having to click through each page just to read a sentence or two is quite cumbersome.

notaplumber 8y ago
There's a thumbnail index for MagicPoint slides: https://www.openbsd.org/papers/ru13-deraadt/index.html https://www.openbsd.org/papers/ru13-deraadt/index.html I also highly recommend checking OpenBSD's events page for additional slides/papers and videos. https://www.openbsd.org/events.html https://www.openbsd.org/events.html
willvarfar 8y ago
Its talk slides, but I personally find the slides easy to just read, even if you have to keep clicking for the next slide. A quick googling finds this https://events.yandex.com/lib/talks/103/ https://events.yandex.com/lib/talks/103/ which is, I think, Theo presenting the slides on part II.
cpach 8y ago
Would be neat with a keyboard shortcut in one’s browser that would go the the next page. (E.g. increase 00001 to 00002, etc.)