Go to file
Nicolai Stange babba4bf53 crypto: drbg - track whether DRBG was seeded with !rng_is_initialized()
commit 2bcd254438 upstream.

Currently, the DRBG implementation schedules asynchronous works from
random_ready_callbacks for reseeding the DRBG instances with output from
get_random_bytes() once the latter has sufficient entropy available.

However, as the get_random_bytes() initialization state can get queried by
means of rng_is_initialized() now, there is no real need for this
asynchronous reseeding logic anymore and it's better to keep things simple
by doing it synchronously when needed instead, i.e. from drbg_generate()
once rng_is_initialized() has flipped to true.

Of course, for this to work, drbg_generate() would need some means by which
it can tell whether or not rng_is_initialized() has flipped to true since
the last seeding from get_random_bytes(). Or equivalently, whether or not
the last seed from get_random_bytes() has happened when
rng_is_initialized() was still evaluating to false.

As it currently stands, enum drbg_seed_state allows for the representation
of two different DRBG seeding states: DRBG_SEED_STATE_UNSEEDED and
DRBG_SEED_STATE_FULL. The former makes drbg_generate() to invoke a full
reseeding operation involving both, the rather expensive jitterentropy as
well as the get_random_bytes() randomness sources. The DRBG_SEED_STATE_FULL
state on the other hand implies that no reseeding at all is required for a
!->pr DRBG variant.

Introduce the new DRBG_SEED_STATE_PARTIAL state to enum drbg_seed_state for
representing the condition that a DRBG was being seeded when
rng_is_initialized() had still been false. In particular, this new state
implies that
- the given DRBG instance has been fully seeded from the jitterentropy
  source (if enabled)
- and drbg_generate() is supposed to reseed from get_random_bytes()
  *only* once rng_is_initialized() turns to true.

Up to now, the __drbg_seed() helper used to set the given DRBG instance's
->seeded state to constant DRBG_SEED_STATE_FULL. Introduce a new argument
allowing for the specification of the to be written ->seeded value instead.
Make the first of its two callers, drbg_seed(), determine the appropriate
value based on rng_is_initialized(). The remaining caller,
drbg_async_seed(), is known to get invoked only once rng_is_initialized()
is true, hence let it pass constant DRBG_SEED_STATE_FULL for the new
argument to __drbg_seed().

There is no change in behaviour, except for that the pr_devel() in
drbg_generate() would now report "unseeded" for ->pr DRBG instances which
had last been seeded when rng_is_initialized() was still evaluating to
false.

Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Stephan Müller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-22 14:11:18 +02:00
arch xtensa: use fallback for random_get_entropy() instead of zero 2022-06-22 14:11:15 +02:00
block block: fix bio_clone_blkg_association() to associate with proper blkcg_gq 2022-06-14 18:11:50 +02:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: drbg - track whether DRBG was seeded with !rng_is_initialized() 2022-06-22 14:11:18 +02:00
Documentation random: fix sysctl documentation nits 2022-06-22 14:11:14 +02:00
drivers Revert "random: use static branch for crng_ready()" 2022-06-22 14:11:18 +02:00
fs compat_ioctl: remove /dev/random commands 2022-06-22 14:11:03 +02:00
include crypto: drbg - track whether DRBG was seeded with !rng_is_initialized() 2022-06-22 14:11:18 +02:00
init random: handle latent entropy and command line from random_init() 2022-06-22 14:11:17 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-14 18:11:41 +02:00
kernel timekeeping: Add raw clock fallback for random_get_entropy() 2022-06-22 14:11:15 +02:00
lib random: remove ratelimiting for in-kernel unseeded randomness 2022-06-22 14:11:17 +02:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm random: move randomize_page() into mm where it belongs 2022-06-22 14:11:17 +02:00
net tcp: fix tcp_mtup_probe_success vs wrong snd_cwnd 2022-06-14 18:12:03 +02:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts scripts/gdb: change kernel config dumping method 2022-06-14 18:12:02 +02:00
security efi: Do not import certificates from UEFI Secure Boot for T2 Macs 2022-06-14 18:11:44 +02:00
sound ALSA: hda/conexant - Fix loopback issue with CX20632 2022-06-14 18:12:02 +02:00
tools netfilter: nat: really support inet nat without l3 address 2022-06-14 18:11:57 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: Prevent module exit until all VMs are freed 2022-04-15 14:18:27 +02:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS MAINTAINERS: co-maintain random.c 2022-06-22 14:11:05 +02:00
Makefile Linux 5.4.199 2022-06-16 13:23:32 +02:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.