This is a note to let you know that I've just added the patch titled
x86/tsc: Use fallback for random_get_entropy() instead of zero
to the 4.14-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:
x86-tsc-use-fallback-for-random_get_entropy-instead-of-zero.patch
and it can be found in the queue-4.14 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 Jun 16 07:08:33 PM CEST 2022
From: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
Date: Fri, 8 Apr 2022 18:03:13 +0200
Subject: x86/tsc: Use fallback for random_get_entropy() instead of zero
From: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
commit 3bd4abc07a267e6a8b33d7f8717136e18f921c53 upstream.
In the event that random_get_entropy() can't access a cycle counter or
similar, falling back to returning 0 is suboptimal. Instead, fallback
to calling random_get_entropy_fallback(), which isn't extremely high
precision or guaranteed to be entropic, but is certainly better than
returning zero all the time.
If CONFIG_X86_TSC=n, then it's possible for the kernel to run on systems
without RDTSC, such as 486 and certain 586, so the fallback code is only
required for that case.
As well, fix up both the new function and the get_cycles() function from
which it was derived to use cpu_feature_enabled() rather than
boot_cpu_has(), and use !IS_ENABLED() instead of #ifndef.
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/timex.h | 9 +++++++++
arch/x86/include/asm/tsc.h | 7 +++----
2 files changed, 12 insertions(+), 4 deletions(-)
--- a/arch/x86/include/asm/timex.h
+++ b/arch/x86/include/asm/timex.h
@@ -5,6 +5,15 @@
#include <asm/processor.h>
#include <asm/tsc.h>
+static inline unsigned long random_get_entropy(void)
+{
+ if (!IS_ENABLED(CONFIG_X86_TSC) &&
+ !cpu_feature_enabled(X86_FEATURE_TSC))
+ return random_get_entropy_fallback();
+ return rdtsc();
+}
+#define random_get_entropy random_get_entropy
+
/* Assume we use the PIT time source for the clock tick */
#define CLOCK_TICK_RATE PIT_TICK_RATE
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -22,13 +22,12 @@ extern void disable_TSC(void);
static inline cycles_t get_cycles(void)
{
-#ifndef CONFIG_X86_TSC
- if (!boot_cpu_has(X86_FEATURE_TSC))
+ if (!IS_ENABLED(CONFIG_X86_TSC) &&
+ !cpu_feature_enabled(X86_FEATURE_TSC))
return 0;
-#endif
-
return rdtsc();
}
+#define get_cycles get_cycles
extern struct system_counterval_t convert_art_to_tsc(u64 art);
Patches currently in stable-queue which might be from Jason@xxxxxxxxx are
queue-4.14/random-do-not-take-pool-spinlock-at-boot.patch
queue-4.14/random-remove-kernel.random.read_wakeup_threshold.patch
queue-4.14/random-simplify-arithmetic-function-flow-in-account.patch
queue-4.14/random-order-timer-entropy-functions-below-interrupt-functions.patch
queue-4.14/random-introduce-drain_entropy-helper-to-declutter-crng_reseed.patch
queue-4.14/random-fix-locking-in-crng_fast_load.patch
queue-4.14/random-cleanup-uuid-handling.patch
queue-4.14/random-group-userspace-read-write-functions.patch
queue-4.14/random-make-credit_entropy_bits-always-safe.patch
queue-4.14/latent_entropy-avoid-build-error-when-plugin-cflags-are-not-set.patch
queue-4.14/revert-hwrng-core-freeze-khwrng-thread-during-suspend.patch
queue-4.14/drivers-char-random.c-make-primary_crng-static.patch
queue-4.14/random-do-not-re-init-if-crng_reseed-completes-before-primary-init.patch
queue-4.14/random-always-fill-buffer-in-get_random_bytes_wait.patch
queue-4.14/random-use-proper-jiffies-comparison-macro.patch
queue-4.14/init-call-time_init-before-rand_initialize.patch
queue-4.14/random-split-primary-secondary-crng-init-paths.patch
queue-4.14/random-pull-add_hwgenerator_randomness-declaration-into-random.h.patch
queue-4.14/random-unify-early-init-crng-load-accounting.patch
queue-4.14/drivers-char-random.c-remove-unused-stuct-poolinfo-poolbits.patch
queue-4.14/random-use-blake2s-instead-of-sha1-in-extraction.patch
queue-4.14/random-make-cpu-trust-a-boot-parameter.patch
queue-4.14/random-convert-to-using-fops-write_iter.patch
queue-4.14/random-initialize-chacha20-constants-with-correct-endianness.patch
queue-4.14/random-remove-incomplete-last_data-logic.patch
queue-4.14/random-group-entropy-extraction-functions.patch
queue-4.14/random-optimize-add_interrupt_randomness.patch
queue-4.14/random-add-proper-spdx-header.patch
queue-4.14/linux-random.h-remove-arch_has_random-arch_has_random_seed.patch
queue-4.14/random-rewrite-header-introductory-comment.patch
queue-4.14/random-make-dev-random-be-almost-like-dev-urandom.patch
queue-4.14/random-remove-ifdef-d-out-interrupt-bench.patch
queue-4.14/um-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-4.14/lib-crypto-sha1-re-roll-loops-to-reduce-code-size.patch
queue-4.14/random-tie-batched-entropy-generation-to-base_crng-generation.patch
queue-4.14/sparc-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-4.14/random-use-linear-min-entropy-accumulation-crediting.patch
queue-4.14/random-remove-batched-entropy-locking.patch
queue-4.14/xtensa-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-4.14/powerpc-remove-arch_has_random-arch_has_random_seed.patch
queue-4.14/fdt-add-support-for-rng-seed.patch
queue-4.14/random-continually-use-hwgenerator-randomness.patch
queue-4.14/random-access-input_pool_data-directly-rather-than-through-pointer.patch
queue-4.14/random-add-arch_get_random_-long_early.patch
queue-4.14/random-inline-leaves-of-rand_initialize.patch
queue-4.14/random-cleanup-poolinfo-abstraction.patch
queue-4.14/random-wire-up-fops-splice_-read-write-_iter.patch
queue-4.14/random-handle-latent-entropy-and-command-line-from-random_init.patch
queue-4.14/random-remove-use_input_pool-parameter-from-crng_reseed.patch
queue-4.14/random-credit-architectural-init-the-exact-amount.patch
queue-4.14/ia64-define-get_cycles-macro-for-arch-override.patch
queue-4.14/random-replace-custom-notifier-chain-with-standard-one.patch
queue-4.14/random-support-freezable-kthreads-in-add_hwgenerator_randomness.patch
queue-4.14/random-document-get_random_int-family.patch
queue-4.14/random-remove-the-blocking-pool.patch
queue-4.14/random-avoid-initializing-twice-in-credit-race.patch
queue-4.14/random-avoid-warnings-for-config_numa-builds.patch
queue-4.14/crypto-drbg-add-fips-140-2-ctrng-for-noise-source.patch
queue-4.14/random-mark-bootloader-randomness-code-as-__init.patch
queue-4.14/random-zero-buffer-after-reading-entropy-from-userspace.patch
queue-4.14/random-remove-whitespace-and-reorder-includes.patch
queue-4.14/random-ignore-grnd_random-in-getentropy-2.patch
queue-4.14/random-clear-fast-pool-crng-and-batches-in-cpuhp-bring-up.patch
queue-4.14/random-document-add_hwgenerator_randomness-with-other-input-functions.patch
queue-4.14/random-fix-typo-in-add_timer_randomness.patch
queue-4.14/random-do-crng-pre-init-loading-in-worker-rather-than-irq.patch
queue-4.14/powerpc-use-bool-in-archrandom.h.patch
queue-4.14/random-do-not-split-fast-init-input-in-add_hwgenerator_randomness.patch
queue-4.14/timekeeping-add-raw-clock-fallback-for-random_get_entropy.patch
queue-4.14/random-early-initialization-of-chacha-constants.patch
queue-4.14/crypto-drbg-prepare-for-more-fine-grained-tracking-of-seeding-state.patch
queue-4.14/random-delete-code-to-pull-data-into-pools.patch
queue-4.14/crypto-drbg-always-try-to-free-jitter-rng-instance.patch
queue-4.14/random-simplify-entropy-debiting.patch
queue-4.14/random-don-t-reset-crng_init_cnt-on-urandom_read.patch
queue-4.14/random-skip-fast_init-if-hwrng-provides-large-chunk-of-entropy.patch
queue-4.14/random-use-siphash-as-interrupt-entropy-accumulator.patch
queue-4.14/random-avoid-checking-crng_ready-twice-in-random_init.patch
queue-4.14/random-fix-soft-lockup-when-trying-to-read-from-an-uninitialized-blocking-pool.patch
queue-4.14/random-group-sysctl-functions.patch
queue-4.14/random-don-t-let-644-read-only-sysctls-be-written-to.patch
queue-4.14/random-document-crng_fast_key_erasure-destination-possibility.patch
queue-4.14/random-only-wake-up-writers-after-zap-if-threshold-was-passed.patch
queue-4.14/random-use-wait_event_freezable-in-add_hwgenerator_randomness.patch
queue-4.14/random-check-for-signal-and-try-earlier-when-generating-entropy.patch
queue-4.14/random-check-for-signals-every-page_size-chunk-of-dev-random.patch
queue-4.14/arm-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-4.14/random-absorb-fast-pool-into-input-pool-after-fast-load.patch
queue-4.14/random-give-sysctl_random_min_urandom_seed-a-more-sensible-value.patch
queue-4.14/crypto-blake2s-generic-c-library-implementation-and-selftest.patch
queue-4.14/random-cleanup-fractional-entropy-shift-constants.patch
queue-4.14/random-use-rdseed-instead-of-rdrand-in-entropy-extraction.patch
queue-4.14/random-move-rand_initialize-earlier.patch
queue-4.14/random-don-t-wake-crng_init_wait-when-crng_init-1.patch
queue-4.14/random-add-a-urandom_read_nowait-for-random-apis-that-don-t-warn.patch
queue-4.14/random-do-not-sign-extend-bytes-for-rotation-when-mixing.patch
queue-4.14/random-move-initialization-functions-out-of-hot-pages.patch
queue-4.14/random-remove-dead-code-left-over-from-blocking-pool.patch
queue-4.14/drivers-char-random.c-constify-poolinfo_table.patch
queue-4.14/crypto-drbg-track-whether-drbg-was-seeded-with-rng_is_initialized.patch
queue-4.14/random-use-computational-hash-for-entropy-extraction.patch
queue-4.14/random-add-and-use-pr_fmt.patch
queue-4.14/random-round-robin-registers-as-ulong-not-u32.patch
queue-4.14/random-always-wake-up-entropy-writers-after-extraction.patch
queue-4.14/s390-remove-arch_has_random-arch_has_random_seed.patch
queue-4.14/random-do-not-xor-rdrand-when-writing-into-dev-random.patch
queue-4.14/crypto-drbg-make-reseeding-from-get_random_bytes-synchronous.patch
queue-4.14/random-convert-to-entropy_bits-for-better-code-readability.patch
queue-4.14/char-random-add-a-newline-at-the-end-of-the-file.patch
queue-4.14/random-move-randomize_page-into-mm-where-it-belongs.patch
queue-4.14/random-only-call-crng_finalize_init-for-primary_crng.patch
queue-4.14/random-cleanup-integer-types.patch
queue-4.14/random-re-add-removed-comment-about-get_random_-u32-u64-reseeding.patch
queue-4.14/random-unify-cycles_t-and-jiffies-usage-and-types.patch
queue-4.14/random-insist-on-random_get_entropy-existing-in-order-to-simplify.patch
queue-4.14/random-group-initialization-wait-functions.patch
queue-4.14/linux-random.h-mark-config_arch_random-functions-__must_check.patch
queue-4.14/random-remove-unused-extract_entropy-reserved-argument.patch
queue-4.14/random-check-for-signal_pending-outside-of-need_resched-check.patch
queue-4.14/random-access-primary_pool-directly-rather-than-through-pointer.patch
queue-4.14/random-fix-sysctl-documentation-nits.patch
queue-4.14/random-remove-unused-tracepoints.patch
queue-4.14/random-only-read-from-dev-random-after-its-pool-has-received-128-bits.patch
queue-4.14/nios2-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-4.14/random-treat-bootloader-trust-toggle-the-same-way-as-cpu-trust-toggle.patch
queue-4.14/random-make-consistent-usage-of-crng_ready.patch
queue-4.14/lib-crypto-blake2s-move-hmac-construction-into-wireguard.patch
queue-4.14/parisc-define-get_cycles-macro-for-arch-override.patch
queue-4.14/x86-tsc-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-4.14/crypto-chacha20-fix-keystream-alignment-for-chacha20_block.patch
queue-4.14/random-add-grnd_insecure-to-return-best-effort-non-cryptographic-bytes.patch
queue-4.14/random-fix-whitespace-pre-random-bytes-work.patch
queue-4.14/crypto-drbg-move-dynamic-reseed_threshold-adjustments-to-__drbg_seed.patch
queue-4.14/random-check-for-signals-after-page-of-pool-writes.patch
queue-4.14/random-make-random_get_entropy-return-an-unsigned-long.patch
queue-4.14/random-check-for-crng_init-0-in-add_device_randomness.patch
queue-4.14/random-add-a-config-option-to-trust-the-cpu-s-hwrng.patch
queue-4.14/random-remove-unnecessary-unlikely.patch
queue-4.14/random-defer-fast-pool-mixing-to-worker.patch
queue-4.14/random-harmonize-crng-init-done-messages.patch
queue-4.14/crypto-blake2s-include-linux-bug.h-instead-of-asm-bug.h.patch
queue-4.14/random-use-static-branch-for-crng_ready.patch
queue-4.14/random-rather-than-entropy_store-abstraction-use-global.patch
queue-4.14/drivers-char-random.c-remove-unused-dont_count_entropy.patch
queue-4.14/random-remove-extern-from-functions-in-header.patch
queue-4.14/siphash-use-one-source-of-truth-for-siphash-permutations.patch
queue-4.14/random-group-entropy-collection-functions.patch
queue-4.14/random-de-duplicate-input_pool-constants.patch
queue-4.14/random-mix-build-time-latent-entropy-into-pool-at-init.patch
queue-4.14/random-remove-useless-header-comment.patch
queue-4.14/linux-random.h-use-false-with-bool.patch
queue-4.14/maintainers-co-maintain-random.c.patch
queue-4.14/random-remove-outdated-int_max-6-check-in-urandom_read.patch
queue-4.14/m68k-use-fallback-for-random_get_entropy-instead-of-zero.patch
queue-4.14/alpha-define-get_cycles-macro-for-arch-override.patch
queue-4.14/random-mix-bootloader-randomness-into-pool.patch
queue-4.14/random-remove-some-dead-code-of-poolinfo.patch
queue-4.14/random-do-not-use-batches-when-crng_ready.patch
queue-4.14/crypto-drbg-always-seeded-with-sp800-90b-compliant-noise-source.patch
queue-4.14/s390-define-get_cycles-macro-for-arch-override.patch
queue-4.14/random-do-not-pretend-to-handle-premature-next-security-model.patch
queue-4.14/random-avoid-arch_get_random_seed_long-when-collecting-irq-randomness.patch
queue-4.14/random-use-is_enabled-config_numa-instead-of-ifdefs.patch
queue-4.14/random-make-crng-state-queryable.patch
queue-4.14/random-avoid-superfluous-call-to-rdrand-in-crng-extraction.patch
queue-4.14/random-use-symbolic-constants-for-crng_init-states.patch
queue-4.14/random-reseed-more-often-immediately-after-booting.patch
queue-4.14/random-ensure-early-rdseed-goes-through-mixer-on-init.patch
queue-4.14/random-deobfuscate-irq-u32-u64-contributions.patch
queue-4.14/random-do-not-use-input-pool-from-hard-irqs.patch
queue-4.14/random-help-compiler-out-with-fast_mix-by-using-simpler-arguments.patch
queue-4.14/revert-random-use-static-branch-for-crng_ready.patch
queue-4.14/random-fix-crash-on-multiple-early-calls-to-add_bootloader_randomness.patch
queue-4.14/random-return-nbytes-filled-from-hw-rng.patch
queue-4.14/random-account-for-arch-randomness-in-bits.patch
queue-4.14/crypto-blake2s-adjust-include-guard-naming.patch
queue-4.14/random-do-not-allow-user-to-keep-crng-key-around-on-stack.patch
queue-4.14/x86-remove-arch_has_random-arch_has_random_seed.patch
queue-4.14/crypto-deduplicate-le32_to_cpu_array-and-cpu_to_le32_array.patch
queue-4.14/random-remove-ratelimiting-for-in-kernel-unseeded-randomness.patch
queue-4.14/random-remove-unused-irq_flags-argument-from-add_interrupt_randomness.patch
queue-4.14/random-prepend-remaining-pool-constants-with-pool_.patch
queue-4.14/powerpc-define-get_cycles-macro-for-arch-override.patch
queue-4.14/random-remove-unused-output_pool-constants.patch
queue-4.14/mips-use-fallback-for-random_get_entropy-instead-of-just-c0-random.patch
queue-4.14/random-use-hash-function-for-crng_slow_load.patch
queue-4.14/random-fix-typo-in-comments.patch
queue-4.14/random-remove-preempt-disabled-region.patch
queue-4.14/random-use-proper-return-types-on-get_random_-int-long-_wait.patch
