CVS log for src/share/man/man9/cprng.9

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cprng(9): Note ipl must be at most IPL_SOFTSERIAL now.

cprng(9): Forbid use in hard interrupt context.

May need access to the global entropy pool (infrequently).  This way
the global entropy pool lock can be lowered to IPL_SOFTSERIAL too,
with a little additional work.

cprng(9): Remove trailing comma.

Update cprng_strong API documentation.

Should maybe just get rid of the flags arguments.

Update cprng(9) man page for CTR_DRBG -> Hash_DRBG change last year.

Merge changes from current as of 20200406

Pull up following revision(s) (requested by skrll in ticket #805):

	share/man/man9/cprng.9: revision 1.11

Fix cprng_fast64 return type to match code

Fix cprng_fast64 return type to match code

Pull up following revision(s) (requested by riastradh in ticket #605):
	share/man/man9/cprng.9: revision 1.10
Clarify advice about when to use what parts of cprng(9).
Add security model to specify the difference between cprng_strong and
cprng_fast.
Fix code references.  cprng_fast now uses ChaCha8, not RC4.
XXX Would have been nice if they had been called cprng and cprng_weak
to reduce confusion about which one to use, or even random and
weakrandom.  Too late for that now, though.

Clarify advice about when to use what parts of cprng(9).

Add security model to specify the difference between cprng_strong and
cprng_fast.

Fix code references.  cprng_fast now uses ChaCha8, not RC4.

XXX Would have been nice if they had been called cprng and cprng_weak
to reduce confusion about which one to use, or even random and
weakrandom.  Too late for that now, though.

Rebase to HEAD as of a few days ago.

sync with head.

for a reference, the tree before this commit was tagged
as yamt-pagecache-tag8.

this commit was splitted into small chunks to avoid
a limitation of cvs.  ("Protocol error: too many arguments")

Merge riastradh-drm2 to HEAD.

sync with HEAD

Rework cprng(9) man page to reflect the current state of affairs.

- Remove defunct cprng_strong_getflags/setflags.
- Remove defunct cprng_strong_ready.
- Document CPRNG_HARD.
- Omit cprng_strong structure, which is now opaque.
- Specify what can sleep and under what conditions.
- Be a little more consistent about some markup.

This is not the whole story (select/kqueue stuff for /dev/random is
still omitted), and I plan to change it some more (to split
cprng_strong into one routine that unconditionally guarantees as many
bytes as you asked, and another routine that may block or return
partial reads), but this will do until I find the time for those.

Fix dangling sentence vestige in cprng(9).

sync with head

fix some signatures

sync with head

file cprng.9 was added on branch yamt-pagecache on 2012-04-17 00:05:49 +0000

Use more markup. Bump date for previous.

Separate /dev/random pseudodevice implemenation from kernel entropy pool
implementation.  Rewrite pseudodevice code to use cprng_strong(9).

The new pseudodevice is cloning, so each caller gets bits from a stream
generated with its own key.  Users of /dev/urandom get their generators
keyed on a "best effort" basis -- the kernel will rekey generators
whenever the entropy pool hits the high water mark -- while users of
/dev/random get their generators rekeyed every time key-length bits
are output.

The underlying cprng_strong API can use AES-256 or AES-128, but we use
AES-128 because of concerns about related-key attacks on AES-256.  This
improves performance (and reduces entropy pool depletion) significantly
for users of /dev/urandom but does cause users of /dev/random to rekey
twice as often.

Also fixes various bugs (including some missing locking and a reseed-counter
overflow in the CTR_DRBG code) found while testing this.

For long reads, this generator is approximately 20 times as fast as the
old generator (dd with bs=64K yields 53MB/sec on 2Ghz Core2 instead of
2.5MB/sec) and also uses a separate mutex per instance so concurrency
is greatly improved.  For reads of typical key sizes for modern
cryptosystems (16-32 bytes) performance is about the same as the old
code: a little better for 32 bytes, a little worse for 16 bytes.

Spelling.

Whitespace fixes; new sentence, new line; better macro usage.
Sort SEE ALSO.

Add cprng(9) manual page, remove arc4random(9) manual page