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Linus Torvalds: “Do No Harm”

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Re: Linus Torvalds: “Do No Harm”

#211

Post by ThenAsNow »

mschuster91 wrote: post #14
margorczynski wrote: post #6

Quick question - doesn't Linux driver model (they run in kernel-space) create a giant attack vector because of that?

Lots of drivers on Windows, OS X and Linux run in kernel space simply because kernel-to-user-and-back context switches are expensive and so kill performance. I believe the exceptions are printer and scanner drivers (these run in user-space CUPS in OS X/Linux), some filesystem drivers (basically, FUSE-backed) and cheap-ish USB drivers.

But there are ways to reduce the attack surface with minimal impact to performance, e.g. the Microdrivers approach: https://www.cs.rutgers.edu/~vinodg/papers/asplos2008/asplos2...

Re: Linus Torvalds: “Do No Harm”

#212

Post by TickleSteve »

__david__ wrote: post #210
TickleSteve wrote: post #203

Earlier quoted context omitted.

A panic should stop the processor dead, no data should be corrected as a result. Data in flight should not be used if you use transactional I/O and therefore will not be used if a write does not complete.

That's fine in theory, but it didn't stop my disk from being corrupted. If the computer hadn't panicked, my data would still be available.

its not theory... your system wasn't designed to be fault-tolerant in that manner.

Systems that matter, are.

Re: Linus Torvalds: “Do No Harm”

#213

Post by exikyut »

ac29 wrote: post #158
exikyut wrote: post #77

Earlier quoted context omitted.

Hooold it. Some of those things are not like the others. -- I pity the engineers working on ventilation machines and the like. Medical devices are insanely hard to get right; that's neck and neck with aviation testing. I'm reminded of SQLite3's "aviation-grade" TH3 testsuite, which apparently has 100% code coverage. Let's be honest; Linux's monolithic design can't really attain that. I would never use Linux for a med…

>As for a Heartbleed-esque catastrophe, apparently one is going to be announced for Intel ME at the upcoming Blackhat(?) conference in December. I can't wait to hear about it myself. Light on details, but the vulnerabilities are disclosed and fixed [0]. ME updates are already available from many OEMs. [0] https://security-center.intel.com/advisory.aspx?intelid=INTE...

Right. But "don't apply the patch!" is sort of circling as well, because (presuming the Blackhat disclosure is workable, it sounds like it will be but fingers crossed) we might be able to play with our MEs.

Re: Linus Torvalds: “Do No Harm”

#214

Post by exikyut »

TickleSteve wrote: post #115
hpaavola wrote: post #85

Earlier quoted context omitted.

Many medical devices run Linux. Most (AFAIK) patient monitors run Linux; GE and Philips (the biggest is business) both run on Linux. Those are the devices that keep you alive during surgery, make sure that those who are born too early (I don't know the English term here) are doing ok, monitor you state while you are in ambulance etc.

No... Many medical devices run Linux as a User-Interface ... (or Windows for that matter). The actual safety-critical portion of these systems is rarely running Linux, but rather on a bare-metal micro.

That makes a lot of sense.

I'm reminded of a UAV doing the same thing. It ran L4 for low-level control, realtime scheduling, and security, and then virtualized Linux on top of that.

Sounds unbelievably clunky on the surface, then you realize it's a remarkably useful way to abstract everything cleanly.

Re: Linus Torvalds: “Do No Harm”

#215

Post by tptacek »

Sir_Cmpwn wrote: post #147
lima wrote: post #3

Background: the "kernel self protection project" (KSSP) recently upstreamed the Grsecurity/PAX reference counting implementation which prevents a certain class of security bugs from being exploited. Grsecurity is a security hardening patchset for Linux that makes deliberate trade-offs in favor of security, sacrificing availability if necessary. This, aside from the political issue, is the main reasons why it's hard t…

>If the large companies who use Linux really want to improve kernel security, they need to work with Grsecurity and not against them. It's beyond me how this isn't happening already. It's more that Grsecurity is working against everyone else. They want to pretend the GPL works in a way that it doesn't so that they can sell their patches. Then they make threats to people who say "that's not how the GPL works" and dist…

It's their work. We're not entitled to it.

Re: Linus Torvalds: “Do No Harm”

#217

Post by Sir_Cmpwn »

tptacek wrote: post #215
Sir_Cmpwn wrote: post #147

Earlier quoted context omitted.

>If the large companies who use Linux really want to improve kernel security, they need to work with Grsecurity and not against them. It's beyond me how this isn't happening already. It's more that Grsecurity is working against everyone else. They want to pretend the GPL works in a way that it doesn't so that they can sell their patches. Then they make threats to people who say "that's not how the GPL works" and dist…

It's their work. We're not entitled to it.

Actually, we are. That's how the GPL works.

Re: Linus Torvalds: “Do No Harm”

#218

Post by pcwalton »

tptacek wrote: post #215
Sir_Cmpwn wrote: post #147

Earlier quoted context omitted.

>If the large companies who use Linux really want to improve kernel security, they need to work with Grsecurity and not against them. It's beyond me how this isn't happening already. It's more that Grsecurity is working against everyone else. They want to pretend the GPL works in a way that it doesn't so that they can sell their patches. Then they make threats to people who say "that's not how the GPL works" and dist…

It's their work. We're not entitled to it.

Bruce Perens, however, is entitled to not be the victim of Spender's legal harassment for exercising his First Amendment rights to disagree [1].

I have no dog in this fight whatsoever; I don't know anybody involved. But in general I have little sympathy for people, however talented, who waste taxpayers' money with bogus legal action.

[1]: https://thenewstack.io/open-source-pioneer-bruce-perens-sued...

Re: Linus Torvalds: “Do No Harm”

#219

Post by tptacek »

Sir_Cmpwn wrote: post #217
tptacek wrote: post #215

Earlier quoted context omitted.

It's their work. We're not entitled to it.

Actually, we are. That's how the GPL works.

No, it's not. The GPL on the Linux kernel means that grsec can't distribute a new Linux kernel with their patches while withholding code. That's not what they're doing. If I write a Linux kernel patch on a consulting project, I am absolutely not required to publish it.

Re: Linus Torvalds: “Do No Harm”

#220

Post by Sir_Cmpwn »

tptacek wrote: post #219
Sir_Cmpwn wrote: post #217

Earlier quoted context omitted.

Actually, we are. That's how the GPL works.

No, it's not. The GPL on the Linux kernel means that grsec can't distribute a new Linux kernel with their patches while withholding code. That's not what they're doing. If I write a Linux kernel patch on a consulting project, I am absolutely not required to publish it.

Right, but they do distribute modified kernels, and we are therefore entitled to their work.
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