Try to make sudo less vulnerable to Rowhammer attacks
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Re: Try to make sudo less vulnerable to Rowhammer attacks
#2Having to code like this everywhere would be hell!
Scroll to the top for the reference to the Mayhem attack it's trying to guard against.
Re: Try to make sudo less vulnerable to Rowhammer attacks
#3This is deeply interesting.
I've sometimes contemplated the possibility of doing things like this to guard against memory errors causing mis-entry to particularly critical control flow paths - this is certainly an example of that. But never heard of anyone actually trying to do this until now.
A "how to write rowhammer-resistant code" writeup would definitely be useful here - even if it is definitely something people cannot do for anything, I can certainly see cases where there is a case for it.
Re: Try to make sudo less vulnerable to Rowhammer attacks
#4Seems like an interesting compiler level protection, a decorator for enums so that they are compiled to values with maximum hamming distance between them.
Re: Try to make sudo less vulnerable to Rowhammer attacks
#5Couldn't compilers be configured to use such values for for any enum type? And maybe even auto-insert the appropriate check in the final unchecked else anywhere that enum type is otherwise exhaustively checked?
Re: Try to make sudo less vulnerable to Rowhammer attacks
#6Interesting it’s the exact opposite of Gray code’s goal, I suppose this has been studied, with fixed size words maximal distance problems are tractable.
Re: Try to make sudo less vulnerable to Rowhammer attacks
#7This wikipedia article must surely be inaccurate:
https://en.wikipedia.org/wiki/Row_hammer
The initial research into the row hammer effect, published in June 2014, described the nature of disturbance errors and indicated the potential for constructing an attack, but did not provide any examples of a working security exploit. [1]
By my recollection there was a discussion of rowhammer and making it work on a (original) Freenode channel circa 2010 (or earlier) in response to a related thread on a reddit security hacking subreddit.
ie: it was being discussed in public channels some four years prior to a paper cited as "initial research".
Addendum: Mind you, lots of things get kicked about and implemented before actual papers appear on them for the first time in public.
Re: Try to make sudo less vulnerable to Rowhammer attacks
#8This wikipedia article must surely be inaccurate: https://en.wikipedia.org/wiki/Row_hammer The initial research into the row hammer effect, published in June 2014, described the nature of disturbance errors and indicated the potential for constructing an attack, but did not provide any examples of a working security exploit. [1] [1] (June 24, 2014). "Flipping Bits in Memory Without Accessing Them: An Experimental Stu…
Well, that quote from Wikipedia says the published paper didn't include a working exploit. That might be true even if a working exploit was available after the paper was written and submitted but before it was published. (I don't know if this is the case here, but this sort of thing is common in scientific publishing.)
Re: Try to make sudo less vulnerable to Rowhammer attacks
#9Is there any reason for the void cast here? Theres no return value in use.
(void)strlcpy(des_pass, pass,sizeof(des_pass));
Re: Try to make sudo less vulnerable to Rowhammer attacks
#10Couldn't compilers be configured to use such values for for any enum type? And maybe even auto-insert the appropriate check in the final unchecked else anywhere that enum type is otherwise exhaustively checked?
Yes it's possible, but it's not desirable. It wouldn't be backwards compatible, and not safe for shared libraries. It's better suited for a linter-type error/warning.