This is a note to let you know that I've just added the patch titled
random: do not use batches when !crng_ready()
to the 5.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
random-do-not-use-batches-when-crng_ready.patch
and it can be found in the queue-5.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu May 26 04:17:01 PM CEST 2022
From: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
Date: Tue, 3 May 2022 14:14:32 +0200
Subject: random: do not use batches when !crng_ready()
From: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
commit cbe89e5a375a51bbb952929b93fa973416fea74e upstream.
It's too hard to keep the batches synchronized, and pointless anyway,
since in !crng_ready(), we're updating the base_crng key really often,
where batching only hurts. So instead, if the crng isn't ready, just
call into get_random_bytes(). At this stage nothing is performance
critical anyhow.
Cc: Theodore Ts'o <tytso@xxxxxxx>
Reviewed-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/char/random.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -465,10 +465,8 @@ static void crng_pre_init_inject(const v
if (account) {
crng_init_cnt += min_t(size_t, len, CRNG_INIT_CNT_THRESH - crng_init_cnt);
- if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) {
- ++base_crng.generation;
+ if (crng_init_cnt >= CRNG_INIT_CNT_THRESH)
crng_init = 1;
- }
}
spin_unlock_irqrestore(&base_crng.lock, flags);
@@ -624,6 +622,11 @@ u64 get_random_u64(void)
warn_unseeded_randomness(&previous);
+ if (!crng_ready()) {
+ _get_random_bytes(&ret, sizeof(ret));
+ return ret;
+ }
+
local_lock_irqsave(&batched_entropy_u64.lock, flags);
batch = raw_cpu_ptr(&batched_entropy_u64);
@@ -658,6 +661,11 @@ u32 get_random_u32(void)
warn_unseeded_randomness(&previous);
+ if (!crng_ready()) {
+ _get_random_bytes(&ret, sizeof(ret));
+ return ret;
+ }
+
local_lock_irqsave(&batched_entropy_u32.lock, flags);
batch = raw_cpu_ptr(&batched_entropy_u32);
Patches currently in stable-queue which might be from Jason@xxxxxxxxx are
queue-5.18/random-remove-ratelimiting-for-in-kernel-unseeded-randomness.patch
queue-5.18/random-fix-sysctl-documentation-nits.patch
queue-5.18/random-help-compiler-out-with-fast_mix-by-using-simpler-arguments.patch
queue-5.18/siphash-use-one-source-of-truth-for-siphash-permutations.patch
queue-5.18/um-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-5.18/random-order-timer-entropy-functions-below-interrupt-functions.patch
queue-5.18/random-unify-batched-entropy-implementations.patch
queue-5.18/random-make-consistent-use-of-buf-and-len.patch
queue-5.18/random-move-randomize_page-into-mm-where-it-belongs.patch
queue-5.18/random-use-first-128-bits-of-input-as-fast-init.patch
queue-5.18/random-use-proper-return-types-on-get_random_-int-long-_wait.patch
queue-5.18/s390-define-get_cycles-macro-for-arch-override.patch
queue-5.18/timekeeping-add-raw-clock-fallback-for-random_get_entropy.patch
queue-5.18/random-use-static-branch-for-crng_ready.patch
queue-5.18/arm-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-5.18/mips-use-fallback-for-random_get_entropy-instead-of-just-c0-random.patch
queue-5.18/random-avoid-initializing-twice-in-credit-race.patch
queue-5.18/random-move-initialization-functions-out-of-hot-pages.patch
queue-5.18/random-do-not-pretend-to-handle-premature-next-security-model.patch
queue-5.18/random-do-not-use-batches-when-crng_ready.patch
queue-5.18/m68k-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-5.18/random-move-initialization-out-of-reseeding-hot-path.patch
queue-5.18/x86-tsc-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-5.18/random-credit-architectural-init-the-exact-amount.patch
queue-5.18/random-check-for-signals-after-page-of-pool-writes.patch
queue-5.18/random-remove-extern-from-functions-in-header.patch
queue-5.18/random-do-not-use-input-pool-from-hard-irqs.patch
queue-5.18/random-wire-up-fops-splice_-read-write-_iter.patch
queue-5.18/random-insist-on-random_get_entropy-existing-in-order-to-simplify.patch
queue-5.18/powerpc-define-get_cycles-macro-for-arch-override.patch
queue-5.18/parisc-define-get_cycles-macro-for-arch-override.patch
queue-5.18/sparc-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-5.18/nios2-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-5.18/init-call-time_init-before-rand_initialize.patch
queue-5.18/riscv-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-5.18/ia64-define-get_cycles-macro-for-arch-override.patch
queue-5.18/random-handle-latent-entropy-and-command-line-from-random_init.patch
queue-5.18/random-use-proper-jiffies-comparison-macro.patch
queue-5.18/alpha-define-get_cycles-macro-for-arch-override.patch
queue-5.18/random-convert-to-using-fops-read_iter.patch
queue-5.18/xtensa-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-5.18/random-use-symbolic-constants-for-crng_init-states.patch
queue-5.18/random-convert-to-using-fops-write_iter.patch
