Sandy Harris <sandyinchina@xxxxxxxxx> wrote: > Jason A. Donenfeld <Jason@xxxxxxxxx> wrote: > > > Thought I should mention here that I've written up the various RNG > > things I've been working on for 5.17 & 5.18 here: > > https://www.zx2c4.com/projects/linux-rng-5.17-5.18/ . > > > > Feel free to discuss on list here if you'd like, or if you see > > something you don't like, I'll happily review patches! > > Your code includes: > > enum { > POOL_BITS = BLAKE2S_HASH_SIZE * 8, > POOL_MIN_BITS = POOL_BITS /* No point in settling for less. */ > }; > > static struct { > struct blake2s_state hash; > spinlock_t lock; > unsigned int entropy_count; > } input_pool = { > .hash.h = { BLAKE2S_IV0 ^ (0x01010000 | BLAKE2S_HASH_SIZE), > BLAKE2S_IV1, BLAKE2S_IV2, BLAKE2S_IV3, BLAKE2S_IV4, > BLAKE2S_IV5, BLAKE2S_IV6, BLAKE2S_IV7 }, > .hash.outlen = BLAKE2S_HASH_SIZE, > .lock = __SPIN_LOCK_UNLOCKED(input_pool.lock), > }; > > As far as I can tell, you have eliminated the 4K-bit input pool > that this driver has always used & are just using the hash > context as the input pool. To me, this looks like an error. > > A side effect of that is losing the latent-entropy attribute > on input_pool[] so we no longer get initialisation from > the plugin. Another error. I could see reasonable arguments for reducing the size of the input pool since that would save both kernel memory and time used by the hash. Personally, though, I would not consider anything < 2Kbits without seeing strong arguments to justify it. You seem to have gone to 512 bits without showing any analysis to justify it. Have I just missed them?
