Re: Patch: rework kernel random number subsystem (*nearly final*)

[email protected] said:
> There's a new patch at http://www.panix.com/~tls/rnd4.diff

I've been running a system with this for a couple of hours now and it appears
stable. (With "rnd3.diff" I got locking related panics indeed.)
Just some mostly formal comments:
-shouldn't the remaining uses of arc4random() be converted to cprng_strong/fast
 as appropriate (what I noticed was in "opencrypto") and arc4random removed
 from public namespace?
-not a big issue, but it seems wrong to me that the arc4random implementation
 in lib/libkern calls back into the kernel's rngtest(). I'd suggest to move
 rngtest() to libkern as well -- it doesn't have any connection to kernel
 specific services.
-while the NIST thing is approved and so, arc4random is still strong enough
 for most uses, as I understand it. The mapping cprng_fast/strong to
 arc4random/nist_ctr could be controlled by some kernel defines, with the
 option to map both to arc4random. At least I wouldn't remove all the
 infrastructure which makes rijndael an optional kernel component, in case
 someone wants to do this later.
-would it be feasible to use the opencrypto framework for AES stuff, to
 get crypto hardware support? From a brief look at the code, my impression
 is that key scheduling code may be called at random number extraction
 time. With opencrypto, as it looks now, this would mean memory allocations
 etc. which would be too expensive. Did you look at this?
-the aes256 header seems to be unused.
-not directly related: What is the "Mersenne Twister" code in libkern
 good for?

best regards
Matthias



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