[GIT PULL] random number generator fixes for 6.2-rc1
From: Jason A. Donenfeld
Date: Sat Dec 10 2022 - 14:47:49 EST
Hi Linus,
Please pull the following random number generator updates for 6.2-rc1:
- Replacing prandom_u32_max() and various open-coded variants of it, there is
now a new family of functions that uses fast rejection sampling to choose
properly uniformly random numbers within an interval:
* get_random_u32_below(ceil) - [0, ceil)
* get_random_u32_above(floor) - (floor, U32_MAX]
* get_random_u32_inclusive(floor, ceil) - [floor, ceil]
Coccinelle was used to convert all current users of prandom_u32_max(), as
well as many open-coded patterns, resulting in improvements throughout the
tree.
I'll have a "late" 6.1-rc1 pull for you that removes the now unused
prandom_u32_max() function, just in case any other trees add a new use case
of it that needs to converted. According to linux-next, there may be two
trivial cases of prandom_u32_max() reintroductions that are fixable with a
's/.../.../'. So I'll have for you a final conversion patch doing that
alongside the removal patch during the second week, before you cut rc1.
This is a treewide change that touches many files throughout, so it would
probably make sense to merge this pull early.
- More consistent use of get_random_canary().
- Updates to comments, documentation, tests, headers, and simplification in
configuration.
- The arch_get_random*_early() abstraction was only used by arm64 and wasn't
entirely useful, so this has been replaced by code that works in all
relevant contexts.
- The kernel will use and manage random seeds in non-volatile EFI variables,
refreshing a variable with a fresh seed when the RNG is initialized. The RNG
GUID namespace is then hidden from efivarfs to prevent accidental leakage.
These changes are split into random.c infrastructure code used in the EFI
subsystem, in this pull request, and related support inside of EFISTUB, in
Ard's EFI tree. These are co-dependent for full functionality, but the order
of merging doesn't matter.
- Part of the infrastructure added for the EFI support is also used for an
improvement to the way vsprintf initializes its siphash key, replacing an
sleep loop wart.
- The hardware RNG framework now always calls its correct random.c input
function, add_hwgenerator_randomness(), rather than sometimes going through
helpers better suited for other cases.
- The add_latent_entropy() function has long been called from the fork
handler, but is a no-op when the latent entropy gcc plugin isn't used,
which is fine for the purposes of latent entropy. But it was missing out on
the cycle counter that was also being mixed in beside the latent entropy
variable. So now, if the latent entropy gcc plugin isn't enabled,
add_latent_entropy() will expand to a call to add_device_randomness(NULL,
0), which adds a cycle counter, without the absent latent entropy variable.
- The RNG is now reseeded from a delayed worker, rather than on demand when
used. Always running from a worker allows it to make use of the CPU RNG on
platforms like S390x, whose instructions are too slow to do so from
interrupts. It also has the effect of adding in new inputs more frequently
with more regularity, amounting to a long term transcript of random values.
Plus, it helps a bit with the upcoming vDSO implementation (which isn't yet
ready for 6.2).
- The jitter entropy algorithm now tries to execute on many different CPUs,
round-robining, in hopes of hitting even more memory latencies and other
unpredictable effects. It also will mix in a cycle counter when the entropy
timer fires, in addition to being mixed in from the main loop, to account
more explicitly for fluctuations in that timer firing. And the state it
touches is now kept within the same cache line, so that it's assured that
the different execution contexts will cause latencies.
There are also a few RNG-related changes that will be arriving to you via
other trees:
- The hardware RNG framework will now pass creditable randomness from much
more dedicated RNG hardware than before, which lets the RNG be initialized
even faster on various hardware without RDRAND but with a dedicated RNG
chip. Along with many other changes here and in random.c throughout the last
few cycles, the overall push has been centered around trying to productively
make use of all of the various random sources the kernel has access to, in
hopes of chipping away at the boot time entropy availability issue.
- EFISTUB will concatenate seeds passed via an EFI configuration table along
with the ones it generates, so that EFI bootloaders, such as systemd-boot or
systemd-stub, can do their own RNG seed management using various writable
media available to those bootloaders, and then pass the seed on directly to
the kernel, so that it's used at the earliest available opportunity in boot.
The code for this is already in the systemd tree and will be part of their
next release. Hopefully other bootloaders will also follow that pattern.
- Since get_random_long() now always makes use of RDRAND (if available) before
the RNG is fully initialized, calling get_random_long() is always better
during all stages of boot than calling arch_get_random_longs() directly. So
the x86 espfix code no arranges its slots based on a call to get_random_long(),
rather than calling RDRAND/RDTSC itself. This is part of a larger effort to
cleanup direct calls to arch_get_random_*(), which is more of a private
implementation detail of random.c than a general purpose API. After this
reaches your tree from tip, I'll have an archrandom.h cleanup patch as part
of my "late" 6.2-rc1 pull.
Thanks,
Jason
The following changes since commit 094226ad94f471a9f19e8f8e7140a09c2625abaa:
Linux 6.1-rc5 (2022-11-13 13:12:55 -0800)
are available in the Git repository at:
https://git.kernel.org/pub/scm/linux/kernel/git/crng/random.git tags/random-6.2-rc1-for-linus
for you to fetch changes up to 3e6743e28b9b43d37ced234bdf8e19955d0216f8:
random: include <linux/once.h> in the right header (2022-12-04 14:37:08 +0100)
----------------------------------------------------------------
Random number generator fixes for Linux 6.2-rc1.
----------------------------------------------------------------
Christophe JAILLET (1):
random: include <linux/once.h> in the right header
Jason A. Donenfeld (22):
kcsan: remove rng selftest
random: use rejection sampling for uniform bounded random integers
random: add helpers for random numbers with given floor or range
treewide: use get_random_u32_below() instead of deprecated function
treewide: use get_random_u32_{above,below}() instead of manual loop
treewide: use get_random_u32_inclusive() when possible
stackprotector: move get_random_canary() into stackprotector.h
stackprotector: actually use get_random_canary()
random: use random.trust_{bootloader,cpu} command line option only
random: remove early archrandom abstraction
random: adjust comment to account for removed function
random: modernize documentation comment on get_random_bytes()
hw_random: use add_hwgenerator_randomness() for early entropy
random: always mix cycle counter in add_latent_entropy()
random: reseed in delayed work rather than on-demand
random: add back async readiness notifier
vsprintf: initialize siphash key using notifier
efi: random: refresh non-volatile random seed when RNG is initialized
random: remove extraneous period and add a missing one in comments
random: spread out jitter callback to different CPUs
random: mix in cycle counter when jitter timer fires
random: align entropy_timer_state to cache line
Documentation/admin-guide/kernel-parameters.txt | 20 +-
arch/arm/include/asm/stackprotector.h | 9 +-
arch/arm/kernel/process.c | 2 +-
arch/arm64/include/asm/archrandom.h | 48 +---
arch/arm64/include/asm/stackprotector.h | 9 +-
arch/arm64/kernel/process.c | 2 +-
arch/csky/include/asm/stackprotector.h | 10 +-
arch/loongarch/kernel/process.c | 2 +-
arch/loongarch/kernel/vdso.c | 2 +-
arch/mips/include/asm/stackprotector.h | 9 +-
arch/mips/kernel/process.c | 2 +-
arch/mips/kernel/vdso.c | 2 +-
arch/parisc/kernel/vdso.c | 2 +-
arch/powerpc/configs/microwatt_defconfig | 1 -
arch/powerpc/crypto/crc-vpmsum_test.c | 4 +-
arch/powerpc/include/asm/stackprotector.h | 10 +-
arch/powerpc/kernel/process.c | 2 +-
arch/riscv/include/asm/stackprotector.h | 10 +-
arch/s390/configs/debug_defconfig | 2 -
arch/s390/configs/defconfig | 2 -
arch/s390/configs/zfcpdump_defconfig | 1 -
arch/s390/kernel/process.c | 2 +-
arch/s390/kernel/vdso.c | 2 +-
arch/sh/include/asm/stackprotector.h | 10 +-
arch/sparc/vdso/vma.c | 2 +-
arch/um/kernel/process.c | 2 +-
arch/x86/entry/vdso/vma.c | 2 +-
arch/x86/include/asm/stackprotector.h | 14 +-
arch/x86/kernel/cpu/common.c | 2 +-
arch/x86/kernel/module.c | 2 +-
arch/x86/kernel/process.c | 2 +-
arch/x86/kernel/setup_percpu.c | 2 +-
arch/x86/kernel/smpboot.c | 1 +
arch/x86/mm/pat/cpa-test.c | 4 +-
arch/x86/xen/enlighten_pv.c | 2 +-
arch/xtensa/include/asm/stackprotector.h | 9 +-
crypto/rsa-pkcs1pad.c | 2 +-
crypto/testmgr.c | 86 +++----
drivers/block/drbd/drbd_receiver.c | 4 +-
drivers/bus/mhi/host/internal.h | 2 +-
drivers/char/Kconfig | 36 ---
drivers/char/hw_random/core.c | 8 +-
drivers/char/random.c | 261 ++++++++++++++-------
drivers/dma-buf/st-dma-fence-chain.c | 6 +-
drivers/firmware/efi/efi.c | 19 ++
drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
.../gpu/drm/i915/gt/intel_execlists_submission.c | 2 +-
drivers/gpu/drm/i915/intel_memory_region.c | 4 +-
drivers/infiniband/core/cma.c | 2 +-
drivers/infiniband/hw/cxgb4/id_table.c | 4 +-
drivers/infiniband/hw/hns/hns_roce_ah.c | 5 +-
drivers/infiniband/ulp/rtrs/rtrs-clt.c | 2 +-
drivers/md/bcache/request.c | 2 +-
drivers/media/common/v4l2-tpg/v4l2-tpg-core.c | 8 +-
drivers/media/test-drivers/vidtv/vidtv_demod.c | 8 +-
.../media/test-drivers/vivid/vivid-kthread-cap.c | 2 +-
.../media/test-drivers/vivid/vivid-kthread-out.c | 2 +-
drivers/media/test-drivers/vivid/vivid-radio-rx.c | 4 +-
drivers/media/test-drivers/vivid/vivid-sdr-cap.c | 2 +-
drivers/media/test-drivers/vivid/vivid-touch-cap.c | 2 +-
drivers/mmc/core/core.c | 4 +-
drivers/mmc/host/dw_mmc.c | 2 +-
drivers/mtd/nand/raw/nandsim.c | 4 +-
drivers/mtd/tests/mtd_nandecctest.c | 10 +-
drivers/mtd/tests/stresstest.c | 8 +-
drivers/mtd/ubi/debug.c | 2 +-
drivers/mtd/ubi/debug.h | 6 +-
drivers/net/ethernet/broadcom/cnic.c | 2 +-
.../chelsio/inline_crypto/chtls/chtls_io.c | 4 +-
drivers/net/phy/at803x.c | 2 +-
drivers/net/team/team_mode_random.c | 2 +-
drivers/net/wireguard/selftest/allowedips.c | 20 +-
drivers/net/wireguard/timers.c | 4 +-
.../net/wireless/broadcom/brcm80211/brcmfmac/p2p.c | 2 +-
drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c | 2 +-
drivers/pci/p2pdma.c | 2 +-
drivers/s390/scsi/zfcp_fc.c | 2 +-
drivers/scsi/fcoe/fcoe_ctlr.c | 4 +-
drivers/scsi/qedi/qedi_main.c | 2 +-
drivers/scsi/scsi_debug.c | 6 +-
fs/ceph/inode.c | 2 +-
fs/ceph/mdsmap.c | 2 +-
fs/ext2/ialloc.c | 2 +-
fs/ext4/ialloc.c | 2 +-
fs/ext4/mmp.c | 8 +-
fs/ext4/super.c | 5 +-
fs/f2fs/gc.c | 2 +-
fs/f2fs/segment.c | 8 +-
fs/ubifs/debug.c | 8 +-
fs/ubifs/lpt_commit.c | 14 +-
fs/ubifs/tnc_commit.c | 2 +-
fs/xfs/libxfs/xfs_alloc.c | 2 +-
fs/xfs/libxfs/xfs_ialloc.c | 2 +-
fs/xfs/xfs_error.c | 2 +-
include/linux/damon.h | 2 +-
include/linux/nodemask.h | 2 +-
include/linux/prandom.h | 19 +-
include/linux/random.h | 102 +++++---
include/linux/stackprotector.h | 19 ++
kernel/bpf/core.c | 4 +-
kernel/fork.c | 2 +-
kernel/kcsan/selftest.c | 12 +-
kernel/locking/test-ww_mutex.c | 4 +-
kernel/time/clocksource.c | 2 +-
lib/fault-inject.c | 2 +-
lib/find_bit_benchmark.c | 4 +-
lib/kobject.c | 2 +-
lib/reed_solomon/test_rslib.c | 6 +-
lib/sbitmap.c | 4 +-
lib/test-string_helpers.c | 2 +-
lib/test_fprobe.c | 5 +-
lib/test_hexdump.c | 10 +-
lib/test_kprobes.c | 5 +-
lib/test_list_sort.c | 2 +-
lib/test_printf.c | 2 +-
lib/test_rhashtable.c | 6 +-
lib/test_vmalloc.c | 8 +-
lib/vsprintf.c | 14 +-
mm/kasan/kasan_test.c | 6 +-
mm/kfence/core.c | 4 +-
mm/kfence/kfence_test.c | 4 +-
mm/slub.c | 2 +-
mm/swapfile.c | 5 +-
net/802/garp.c | 2 +-
net/802/mrp.c | 2 +-
net/batman-adv/bat_iv_ogm.c | 4 +-
net/batman-adv/bat_v_elp.c | 2 +-
net/batman-adv/bat_v_ogm.c | 4 +-
net/batman-adv/network-coding.c | 2 +-
net/bluetooth/mgmt.c | 5 +-
net/can/j1939/socket.c | 2 +-
net/can/j1939/transport.c | 2 +-
net/ceph/mon_client.c | 2 +-
net/ceph/osd_client.c | 2 +-
net/core/neighbour.c | 4 +-
net/core/pktgen.c | 37 ++-
net/core/stream.c | 2 +-
net/ipv4/icmp.c | 2 +-
net/ipv4/igmp.c | 6 +-
net/ipv4/inet_connection_sock.c | 2 +-
net/ipv4/inet_hashtables.c | 2 +-
net/ipv4/route.c | 4 +-
net/ipv4/tcp_bbr.c | 2 +-
net/ipv4/tcp_input.c | 3 +-
net/ipv6/addrconf.c | 8 +-
net/ipv6/mcast.c | 10 +-
net/ipv6/output_core.c | 8 +-
net/ipv6/route.c | 2 +-
net/netfilter/ipvs/ip_vs_twos.c | 4 +-
net/netfilter/nf_conntrack_core.c | 4 +-
net/netfilter/nf_nat_helper.c | 2 +-
net/netlink/af_netlink.c | 2 +-
net/packet/af_packet.c | 4 +-
net/sched/act_gact.c | 2 +-
net/sched/act_sample.c | 2 +-
net/sched/sch_choke.c | 2 +-
net/sched/sch_netem.c | 4 +-
net/sctp/socket.c | 2 +-
net/sctp/transport.c | 2 +-
net/sunrpc/cache.c | 2 +-
net/sunrpc/xprtsock.c | 2 +-
net/tipc/socket.c | 2 +-
net/vmw_vsock/af_vsock.c | 3 +-
net/xfrm/xfrm_state.c | 2 +-
.../testing/selftests/wireguard/qemu/kernel.config | 2 -
165 files changed, 611 insertions(+), 649 deletions(-)