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In 1448769c9cdb ("random: check for signal_pending() outside of
need_resched() check"), Jann pointed out that we previously were only
checking the TIF_NOTIFY_SIGNAL and TIF_SIGPENDING flags if the process
had TIF_NEED_RESCHED set, which meant in practice, super long reads to
/dev/[u]random would delay signal handling by a long time. I tried this
using the below program, and indeed I wasn't able to interrupt a
/dev/urandom read until after several megabytes had been read. The bug
he fixed has always been there, and so code that reads from /dev/urandom
without checking the return value of read() has mostly worked for a long
time, for most sizes, not just for <= 256.
Maybe it makes sense to keep that code working. The reason it was so
small prior, ignoring the fact that it didn't work anyway, was likely
because /dev/random used to block, and that could happen for pretty
large lengths of time while entropy was gathered. But now, it's just a
chacha20 call, which is extremely fast and is just operating on pure
data, without having to wait for some external event. In that sense,
/dev/[u]random is a lot more like /dev/zero.
Taking a page out of /dev/zero's read_zero() function, it always returns
at least one chunk, and then checks for signals after each chunk. Chunk
sizes there are of length PAGE_SIZE. Let's just copy the same thing for
/dev/[u]random, and check for signals and cond_resched() for every
PAGE_SIZE amount of data. This makes the behavior more consistent with
expectations, and should mitigate the impact of Jann's fix for the
age-old signal check bug.
---- test program ----
#include <unistd.h>
#include <signal.h>
#include <stdio.h>
#include <sys/random.h>
static unsigned char x[~0U];
static void handle(int) { }
int main(int argc, char *argv[])
{
pid_t pid = getpid(), child;
signal(SIGUSR1, handle);
if (!(child = fork())) {
for (;;)
kill(pid, SIGUSR1);
}
pause();
printf("interrupted after reading %zd bytes\n", getrandom(x, sizeof(x), 0));
kill(child, SIGTERM);
return 0;
}
Cc: Jann Horn <jannh@google.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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signal_pending() checks TIF_NOTIFY_SIGNAL and TIF_SIGPENDING, which
signal that the task should bail out of the syscall when possible. This
is a separate concept from need_resched(), which checks
TIF_NEED_RESCHED, signaling that the task should preempt.
In particular, with the current code, the signal_pending() bailout
probably won't work reliably.
Change this to look like other functions that read lots of data, such as
read_zero().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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The fast key erasure RNG design relies on the key that's used to be used
and then discarded. We do this, making judicious use of
memzero_explicit(). However, reads to /dev/urandom and calls to
getrandom() involve a copy_to_user(), and userspace can use FUSE or
userfaultfd, or make a massive call, dynamically remap memory addresses
as it goes, and set the process priority to idle, in order to keep a
kernel stack alive indefinitely. By probing
/proc/sys/kernel/random/entropy_avail to learn when the crng key is
refreshed, a malicious userspace could mount this attack every 5 minutes
thereafter, breaking the crng's forward secrecy.
In order to fix this, we just overwrite the stack's key with the first
32 bytes of the "free" fast key erasure output. If we're returning <= 32
bytes to the user, then we can still return those bytes directly, so
that short reads don't become slower. And for long reads, the difference
is hopefully lost in the amortization, so it doesn't change much, with
that amortization helping variously for medium reads.
We don't need to do this for get_random_bytes() and the various
kernel-space callers, and later, if we ever switch to always batching,
this won't be necessary either, so there's no need to change the API of
these functions.
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jann Horn <jannh@google.com>
Fixes: c92e040d575a ("random: add backtracking protection to the CRNG")
Fixes: 186873c549df ("random: use simpler fast key erasure flow on per-cpu keys")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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In 6f98a4bfee72 ("random: block in /dev/urandom"), we tried to make a
successful try_to_generate_entropy() call *required* if the RNG was not
already initialized. Unfortunately, weird architectures and old
userspaces combined in TCG test harnesses, making that change still not
realistic, so it was reverted in 0313bc278dac ("Revert "random: block in
/dev/urandom"").
However, rather than making a successful try_to_generate_entropy() call
*required*, we can instead make it *best-effort*.
If try_to_generate_entropy() fails, it fails, and nothing changes from
the current behavior. If it succeeds, then /dev/urandom becomes safe to
use for free. This way, we don't risk the regression potential that led
to us reverting the required-try_to_generate_entropy() call before.
Practically speaking, this means that at least on x86, /dev/urandom
becomes safe. Probably other architectures with working cycle counters
will also become safe. And architectures with slow or broken cycle
counters at least won't be affected at all by this change.
So it may not be the glorious "all things are unified!" change we were
hoping for initially, but practically speaking, it makes a positive
impact.
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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add_hwgenerator_randomness() tries to only use the required amount of input
for fast init, but credits all the entropy, rather than a fraction of
it. Since it's hard to determine how much entropy is left over out of a
non-unformly random sample, either give it all to fast init or credit
it, but don't attempt to do both. In the process, we can clean up the
injection code to no longer need to return a value.
Signed-off-by: Jan Varho <jan.varho@gmail.com>
[Jason: expanded commit message]
Fixes: 73c7733f122e ("random: do not throw away excess input to crng_fast_load")
Cc: stable@vger.kernel.org # 5.17+, requires af704c856e88
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator fixes from Jason Donenfeld:
- If a hardware random number generator passes a sufficiently large
chunk of entropy to random.c during early boot, we now skip the
"fast_init" business and let it initialize the RNG.
This makes CONFIG_RANDOM_TRUST_BOOTLOADER=y actually useful.
- We already have the command line `random.trust_cpu=0/1` option for
RDRAND, which let distros enable CONFIG_RANDOM_TRUST_CPU=y while
placating concerns of more paranoid users.
Now we add `random.trust_bootloader=0/1` so that distros can
similarly enable CONFIG_RANDOM_TRUST_BOOTLOADER=y.
- Re-add a comment that got removed by accident in the recent revert.
- Add the spec-compliant ACPI CID for vmgenid, which Microsoft added to
the vmgenid spec at Ard's request during earlier review.
- Restore build-time randomness via the latent entropy plugin, which
was lost when we transitioned to using a hash function.
* tag 'random-5.18-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
random: mix build-time latent entropy into pool at init
virt: vmgenid: recognize new CID added by Hyper-V
random: re-add removed comment about get_random_{u32,u64} reseeding
random: treat bootloader trust toggle the same way as cpu trust toggle
random: skip fast_init if hwrng provides large chunk of entropy
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Prior, the "input_pool_data" array needed no real initialization, and so
it was easy to mark it with __latent_entropy to populate it during
compile-time. In switching to using a hash function, this required us to
specifically initialize it to some specific state, which means we
dropped the __latent_entropy attribute. An unfortunate side effect was
this meant the pool was no longer seeded using compile-time random data.
In order to bring this back, we declare an array in rand_initialize()
with __latent_entropy and call mix_pool_bytes() on that at init, which
accomplishes the same thing as before. We make this __initconst, so that
it doesn't take up space at runtime after init.
Fixes: 6e8ec2552c7d ("random: use computational hash for entropy extraction")
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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Pull dma-mapping updates from Christoph Hellwig:
- do not zero buffer in set_memory_decrypted (Kirill A. Shutemov)
- fix return value of dma-debug __setup handlers (Randy Dunlap)
- swiotlb cleanups (Robin Murphy)
- remove most remaining users of the pci-dma-compat.h API
(Christophe JAILLET)
- share the ABI header for the DMA map_benchmark with userspace
(Tian Tao)
- update the maintainer for DMA MAPPING BENCHMARK (Xiang Chen)
- remove CONFIG_DMA_REMAP (me)
* tag 'dma-mapping-5.18' of git://git.infradead.org/users/hch/dma-mapping:
dma-mapping: benchmark: extract a common header file for map_benchmark definition
dma-debug: fix return value of __setup handlers
dma-mapping: remove CONFIG_DMA_REMAP
media: v4l2-pci-skeleton: Remove usage of the deprecated "pci-dma-compat.h" API
rapidio/tsi721: Remove usage of the deprecated "pci-dma-compat.h" API
sparc: Remove usage of the deprecated "pci-dma-compat.h" API
agp/intel: Remove usage of the deprecated "pci-dma-compat.h" API
alpha: Remove usage of the deprecated "pci-dma-compat.h" API
MAINTAINERS: update maintainer list of DMA MAPPING BENCHMARK
swiotlb: simplify array allocation
swiotlb: tidy up includes
swiotlb: simplify debugfs setup
swiotlb: do not zero buffer in set_memory_decrypted()
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
- A bunch of minor cleanups
- A fix for kexec in Xen dom0 when executed on a high cpu number
- A fix for resuming after suspend of a Xen guest with assigned PCI
devices
- A fix for a crash due to not disabled preemption when resuming as Xen
dom0
* tag 'for-linus-5.18-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen: fix is_xen_pmu()
xen: don't hang when resuming PCI device
arch:x86:xen: Remove unnecessary assignment in xen_apic_read()
xen/grant-table: remove readonly parameter from functions
xen/grant-table: remove gnttab_*transfer*() functions
drivers/xen: use helper macro __ATTR_RW
x86/xen: Fix kerneldoc warning
xen: delay xen_hvm_init_time_ops() if kdump is boot on vcpu>=32
xen: use time_is_before_eq_jiffies() instead of open coding it
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc and other driver updates from Greg KH:
"Here is the big set of char/misc and other small driver subsystem
updates for 5.18-rc1.
Included in here are merges from driver subsystems which contain:
- iio driver updates and new drivers
- fsi driver updates
- fpga driver updates
- habanalabs driver updates and support for new hardware
- soundwire driver updates and new drivers
- phy driver updates and new drivers
- coresight driver updates
- icc driver updates
Individual changes include:
- mei driver updates
- interconnect driver updates
- new PECI driver subsystem added
- vmci driver updates
- lots of tiny misc/char driver updates
All of these have been in linux-next for a while with no reported
problems"
* tag 'char-misc-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (556 commits)
firmware: google: Properly state IOMEM dependency
kgdbts: fix return value of __setup handler
firmware: sysfb: fix platform-device leak in error path
firmware: stratix10-svc: add missing callback parameter on RSU
arm64: dts: qcom: add non-secure domain property to fastrpc nodes
misc: fastrpc: Add dma handle implementation
misc: fastrpc: Add fdlist implementation
misc: fastrpc: Add helper function to get list and page
misc: fastrpc: Add support to secure memory map
dt-bindings: misc: add fastrpc domain vmid property
misc: fastrpc: check before loading process to the DSP
misc: fastrpc: add secure domain support
dt-bindings: misc: add property to support non-secure DSP
misc: fastrpc: Add support to get DSP capabilities
misc: fastrpc: add support for FASTRPC_IOCTL_MEM_MAP/UNMAP
misc: fastrpc: separate fastrpc device from channel context
dt-bindings: nvmem: brcm,nvram: add basic NVMEM cells
dt-bindings: nvmem: make "reg" property optional
nvmem: brcm_nvram: parse NVRAM content into NVMEM cells
nvmem: dt-bindings: Fix the error of dt-bindings check
...
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Pull IPMI updates from Corey Minyard:
- Little fixes for various things people have noticed.
- One enhancement, the IPMI over IPMB (I2c) is modified to allow it to
take a separate sender and receiver device. The Raspberry Pi has an
I2C slave device that cannot send.
* tag 'for-linus-5.17-1' of https://github.com/cminyard/linux-ipmi:
ipmi: initialize len variable
ipmi: kcs: aspeed: Remove old bindings support
ipmi:ipmb: Add the ability to have a separate slave and master device
ipmi:ipmi_ipmb: Unregister the SMI on remove
ipmi: kcs: aspeed: Add AST2600 compatible string
ipmi: ssif: replace strlcpy with strscpy
ipmi/watchdog: Constify ident
ipmi: Add the git repository to the MAINTAINERS file
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The comment about get_random_{u32,u64}() not invoking reseeding got
added in an unrelated commit, that then was recently reverted by
0313bc278dac ("Revert "random: block in /dev/urandom""). So this adds
that little comment snippet back, and improves the wording a bit too.
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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If CONFIG_RANDOM_TRUST_CPU is set, the RNG initializes using RDRAND.
But, the user can disable (or enable) this behavior by setting
`random.trust_cpu=0/1` on the kernel command line. This allows system
builders to do reasonable things while avoiding howls from tinfoil
hatters. (Or vice versa.)
CONFIG_RANDOM_TRUST_BOOTLOADER is basically the same thing, but regards
the seed passed via EFI or device tree, which might come from RDRAND or
a TPM or somewhere else. In order to allow distros to more easily enable
this while avoiding those same howls (or vice versa), this commit adds
the corresponding `random.trust_bootloader=0/1` toggle.
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Graham Christensen <graham@grahamc.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Link: https://github.com/NixOS/nixpkgs/pull/165355
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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At boot time, EFI calls add_bootloader_randomness(), which in turn calls
add_hwgenerator_randomness(). Currently add_hwgenerator_randomness()
feeds the first 64 bytes of randomness to the "fast init"
non-crypto-grade phase. But if add_hwgenerator_randomness() gets called
with more than POOL_MIN_BITS of entropy, there's no point in passing it
off to the "fast init" stage, since that's enough entropy to bootstrap
the real RNG. The "fast init" stage is just there to provide _something_
in the case where we don't have enough entropy to properly bootstrap the
RNG. But if we do have enough entropy to bootstrap the RNG, the current
logic doesn't serve a purpose. So, in the case where we're passed
greater than or equal to POOL_MIN_BITS of entropy, this commit makes us
skip the "fast init" phase.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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Pull drm updates from Dave Airlie:
"Lots of work all over, Intel improving DG2 support, amdkfd CRIU
support, msm new hw support, and faster fbdev support.
dma-buf:
- rename dma-buf-map to iosys-map
core:
- move buddy allocator to core
- add pci/platform init macros
- improve EDID parser deep color handling
- EDID timing type 7 support
- add GPD Win Max quirk
- add yes/no helpers to string_helpers
- flatten syncobj chains
- add nomodeset support to lots of drivers
- improve fb-helper clipping support
- add default property value interface
fbdev:
- improve fbdev ops speed
ttm:
- add a backpointer from ttm bo->ttm resource
dp:
- move displayport headers
- add a dp helper module
bridge:
- anx7625 atomic support, HDCP support
panel:
- split out panel-lvds and lvds bindings
- find panels in OF subnodes
privacy:
- add chromeos privacy screen support
fb:
- hot unplug fw fb on forced removal
simpledrm:
- request region instead of marking ioresource busy
- add panel oreintation property
udmabuf:
- fix oops with 0 pages
amdgpu:
- power management code cleanup
- Enable freesync video mode by default
- RAS code cleanup
- Improve VRAM access for debug using SDMA
- SR-IOV rework special register access and fixes
- profiling power state request ioctl
- expose IP discovery via sysfs
- Cyan skillfish updates
- GC 10.3.7, SDMA 5.2.7, DCN 3.1.6 updates
- expose benchmark tests via debugfs
- add module param to disable XGMI for testing
- GPU reset debugfs register dumping support
amdkfd:
- CRIU support
- SDMA queue fixes
radeon:
- UVD suspend fix
- iMac backlight fix
i915:
- minimal parallel submission for execlists
- DG2-G12 subplatform added
- DG2 programming workarounds
- DG2 accelerated migration support
- flat CCS and CCS engine support for XeHP
- initial small BAR support
- drop fake LMEM support
- ADL-N PCH support
- bigjoiner updates
- introduce VMA resources and async unbinding
- register definitions cleanups
- multi-FBC refactoring
- DG1 OPROM over SPI support
- ADL-N platform enabling
- opregion mailbox #5 support
- DP MST ESI improvements
- drm device based logging
- async flip optimisation for DG2
- CPU arch abstraction fixes
- improve GuC ADS init to work on aarch64
- tweak TTM LRU priority hint
- GuC 69.0.3 support
- remove short term execbuf pins
nouveau:
- higher DP/eDP bitrates
- backlight fixes
msm:
- dpu + dp support for sc8180x
- dp support for sm8350
- dpu + dsi support for qcm2290
- 10nm dsi phy tuning support
- bridge support for dp encoder
- gpu support for additional 7c3 SKUs
ingenic:
- HDMI support for JZ4780
- aux channel EDID support
ast:
- AST2600 support
- add wide screen support
- create DP/DVI connectors
omapdrm:
- fix implicit dma_buf fencing
vc4:
- add CSC + full range support
- better display firmware handoff
panfrost:
- add initial dual-core GPU support
stm:
- new revision support
- fb handover support
mediatek:
- transfer display binding document to yaml format.
- add mt8195 display device binding.
- allow commands to be sent during video mode.
- add wait_for_event for crtc disable by cmdq.
tegra:
- YUV format support
rcar-du:
- LVDS support for M3-W+ (R8A77961)
exynos:
- BGR pixel format for FIMD device"
* tag 'drm-next-2022-03-24' of git://anongit.freedesktop.org/drm/drm: (1529 commits)
drm/i915/display: Do not re-enable PSR after it was marked as not reliable
drm/i915/display: Fix HPD short pulse handling for eDP
drm/amdgpu: Use drm_mode_copy()
drm/radeon: Use drm_mode_copy()
drm/amdgpu: Use ternary operator in `vcn_v1_0_start()`
drm/amdgpu: Remove pointless on stack mode copies
drm/amd/pm: fix indenting in __smu_cmn_reg_print_error()
drm/amdgpu/dc: fix typos in comments
drm/amdgpu: fix typos in comments
drm/amd/pm: fix typos in comments
drm/amdgpu: Add stolen reserved memory for MI25 SRIOV.
drm/amdgpu: Merge get_reserved_allocation to get_vbios_allocations.
drm/amdkfd: evict svm bo worker handle error
drm/amdgpu/vcn: fix vcn ring test failure in igt reload test
drm/amdgpu: only allow secure submission on rings which support that
drm/amdgpu: fixed the warnings reported by kernel test robot
drm/amd/display: 3.2.177
drm/amd/display: [FW Promotion] Release 0.0.108.0
drm/amd/display: Add save/restore PANEL_PWRSEQ_REF_DIV2
drm/amd/display: Wait for hubp read line for Pollock
...
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git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc
Pull ARM driver updates from Arnd Bergmann:
"There are a few separately maintained driver subsystems that we merge
through the SoC tree, notable changes are:
- Memory controller updates, mainly for Tegra and Mediatek SoCs, and
clarifications for the memory controller DT bindings
- SCMI firmware interface updates, in particular a new transport
based on OPTEE and support for atomic operations.
- Cleanups to the TEE subsystem, refactoring its memory management
For SoC specific drivers without a separate subsystem, changes include
- Smaller updates and fixes for TI, AT91/SAMA5, Qualcomm and NXP
Layerscape SoCs.
- Driver support for Microchip SAMA5D29, Tesla FSD, Renesas RZ/G2L,
and Qualcomm SM8450.
- Better power management on Mediatek MT81xx, NXP i.MX8MQ and older
NVIDIA Tegra chips"
* tag 'arm-drivers-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (154 commits)
ARM: spear: fix typos in comments
soc/microchip: fix invalid free in mpfs_sys_controller_delete
soc: s4: Add support for power domains controller
dt-bindings: power: add Amlogic s4 power domains bindings
ARM: at91: add support in soc driver for new SAMA5D29
soc: mediatek: mmsys: add sw0_rst_offset in mmsys driver data
dt-bindings: memory: renesas,rpc-if: Document RZ/V2L SoC
memory: emif: check the pointer temp in get_device_details()
memory: emif: Add check for setup_interrupts
dt-bindings: arm: mediatek: mmsys: add support for MT8186
dt-bindings: mediatek: add compatible for MT8186 pwrap
soc: mediatek: pwrap: add pwrap driver for MT8186 SoC
soc: mediatek: mmsys: add mmsys reset control for MT8186
soc: mediatek: mtk-infracfg: Disable ACP on MT8192
soc: ti: k3-socinfo: Add AM62x JTAG ID
soc: mediatek: add MTK mutex support for MT8186
soc: mediatek: mmsys: add mt8186 mmsys routing table
soc: mediatek: pm-domains: Add support for mt8186
dt-bindings: power: Add MT8186 power domains
soc: mediatek: pm-domains: Add support for mt8195
...
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This reverts commit 6f98a4bfee72c22f50aedb39fb761567969865fe.
It turns out we still can't do this. Way too many platforms that don't
have any real source of randomness at boot and no jitter entropy because
they don't even have a cycle counter.
As reported by Guenter Roeck:
"This causes a large number of qemu boot test failures for various
architectures (arm, m68k, microblaze, sparc32, xtensa are the ones I
observed).
Common denominator is that boot hangs at 'Saving random seed:'"
This isn't hugely unexpected - we tried it, it failed, so now we'll
revert it.
Link: https://lore.kernel.org/all/20220322155820.GA1745955@roeck-us.net/
Reported-and-bisected-by: Guenter Roeck <linux@roeck-us.net>
Cc: Jason Donenfeld <Jason@zx2c4.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull bounds fixes from Kees Cook:
"These are a handful of buffer and array bounds fixes that I've been
carrying in preparation for the coming memcpy improvements and the
enabling of '-Warray-bounds' globally.
There are additional similar fixes in other maintainer's trees, but
these ended up getting carried by me. :)"
* tag 'bounds-fixes-v5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
media: omap3isp: Use struct_group() for memcpy() region
tpm: vtpm_proxy: Check length to avoid compiler warning
alpha: Silence -Warray-bounds warnings
m68k: cmpxchg: Dereference matching size
intel_th: msu: Use memset_startat() for clearing hw header
KVM: x86: Replace memset() "optimization" with normal per-field writes
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git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi
Pull spi updates from Mark Brown:
"The overwhelming bulk of this pull request is a change from Uwe
Kleine-König which changes the return type of the remove() function to
void as part of some wider work he's doing to do this for all bus
types, causing updates to most SPI device drivers. The branch with
that on has been cross merged with a couple of other trees which added
new SPI drivers this cycle, I'm not expecting any build issues
resulting from the change.
Otherwise it's been a relatively quiet release with some new device
support, a few minor features and the welcome completion of the
conversion of the subsystem to use GPIO descriptors rather than
numbers:
- Change return type of remove() to void.
- Completion of the conversion of SPI controller drivers to use GPIO
descriptors rather than numbers.
- Quite a few DT schema conversions.
- Support for multiple SPI devices on a bus in ACPI systems.
- Big overhaul of the PXA2xx SPI driver.
- Support for AMD AMDI0062, Intel Raptor Lake, Mediatek MT7986 and
MT8186, nVidia Tegra210 and Tegra234, Renesas RZ/V2L, Tesla FSD and
Sunplus SP7021"
[ And this is obviously where that spi change that snuck into the
regulator tree _should_ have been :^]
* tag 'spi-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (124 commits)
spi: fsi: Implement a timeout for polling status
spi: Fix erroneous sgs value with min_t()
spi: tegra20: Use of_device_get_match_data()
spi: mediatek: add ipm design support for MT7986
spi: Add compatible for MT7986
spi: sun4i: fix typos in comments
spi: mediatek: support tick_delay without enhance_timing
spi: Update clock-names property for arm pl022
spi: rockchip-sfc: fix platform_get_irq.cocci warning
spi: s3c64xx: Add spi port configuration for Tesla FSD SoC
spi: dt-bindings: samsung: Add fsd spi compatible
spi: topcliff-pch: Prevent usage of potentially stale DMA device
spi: tegra210-quad: combined sequence mode
spi: tegra210-quad: add acpi support
spi: npcm-fiu: Fix typo ("npxm")
spi: Fix Tegra QSPI example
spi: qup: replace spin_lock_irqsave by spin_lock in hard IRQ
spi: cadence: fix platform_get_irq.cocci warning
spi: Update NXP Flexspi maintainer details
dt-bindings: mfd: maxim,max77802: Convert to dtschema
...
|
|
Pull block updates from Jens Axboe:
- BFQ cleanups and fixes (Yu, Zhang, Yahu, Paolo)
- blk-rq-qos completion fix (Tejun)
- blk-cgroup merge fix (Tejun)
- Add offline error return value to distinguish it from an IO error on
the device (Song)
- IO stats fixes (Zhang, Christoph)
- blkcg refcount fixes (Ming, Yu)
- Fix for indefinite dispatch loop softlockup (Shin'ichiro)
- blk-mq hardware queue management improvements (Ming)
- sbitmap dead code removal (Ming, John)
- Plugging merge improvements (me)
- Show blk-crypto capabilities in sysfs (Eric)
- Multiple delayed queue run improvement (David)
- Block throttling fixes (Ming)
- Start deprecating auto module loading based on dev_t (Christoph)
- bio allocation improvements (Christoph, Chaitanya)
- Get rid of bio_devname (Christoph)
- bio clone improvements (Christoph)
- Block plugging improvements (Christoph)
- Get rid of genhd.h header (Christoph)
- Ensure drivers use appropriate flush helpers (Christoph)
- Refcounting improvements (Christoph)
- Queue initialization and teardown improvements (Ming, Christoph)
- Misc fixes/improvements (Barry, Chaitanya, Colin, Dan, Jiapeng,
Lukas, Nian, Yang, Eric, Chengming)
* tag 'for-5.18/block-2022-03-18' of git://git.kernel.dk/linux-block: (127 commits)
block: cancel all throttled bios in del_gendisk()
block: let blkcg_gq grab request queue's refcnt
block: avoid use-after-free on throttle data
block: limit request dispatch loop duration
block/bfq-iosched: Fix spelling mistake "tenative" -> "tentative"
sr: simplify the local variable initialization in sr_block_open()
block: don't merge across cgroup boundaries if blkcg is enabled
block: fix rq-qos breakage from skipping rq_qos_done_bio()
block: flush plug based on hardware and software queue order
block: ensure plug merging checks the correct queue at least once
block: move rq_qos_exit() into disk_release()
block: do more work in elevator_exit
block: move blk_exit_queue into disk_release
block: move q_usage_counter release into blk_queue_release
block: don't remove hctx debugfs dir from blk_mq_exit_queue
block: move blkcg initialization/destroy into disk allocation/release handler
sr: implement ->free_disk to simplify refcounting
sd: implement ->free_disk to simplify refcounting
sd: delay calling free_opal_dev
sd: call sd_zbc_release_disk before releasing the scsi_device reference
...
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git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
"API:
- hwrng core now credits for low-quality RNG devices.
Algorithms:
- Optimisations for neon aes on arm/arm64.
- Add accelerated crc32_be on arm64.
- Add ffdheXYZ(dh) templates.
- Disallow hmac keys < 112 bits in FIPS mode.
- Add AVX assembly implementation for sm3 on x86.
Drivers:
- Add missing local_bh_disable calls for crypto_engine callback.
- Ensure BH is disabled in crypto_engine callback path.
- Fix zero length DMA mappings in ccree.
- Add synchronization between mailbox accesses in octeontx2.
- Add Xilinx SHA3 driver.
- Add support for the TDES IP available on sama7g5 SoC in atmel"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (137 commits)
crypto: xilinx - Turn SHA into a tristate and allow COMPILE_TEST
MAINTAINERS: update HPRE/SEC2/TRNG driver maintainers list
crypto: dh - Remove the unused function dh_safe_prime_dh_alg()
hwrng: nomadik - Change clk_disable to clk_disable_unprepare
crypto: arm64 - cleanup comments
crypto: qat - fix initialization of pfvf rts_map_msg structures
crypto: qat - fix initialization of pfvf cap_msg structures
crypto: qat - remove unneeded assignment
crypto: qat - disable registration of algorithms
crypto: hisilicon/qm - fix memset during queues clearing
crypto: xilinx: prevent probing on non-xilinx hardware
crypto: marvell/octeontx - Use swap() instead of open coding it
crypto: ccree - Fix use after free in cc_cipher_exit()
crypto: ccp - ccp_dmaengine_unregister release dma channels
crypto: octeontx2 - fix missing unlock
hwrng: cavium - fix NULL but dereferenced coccicheck error
crypto: cavium/nitrox - don't cast parameter in bit operations
crypto: vmx - add missing dependencies
MAINTAINERS: Add maintainer for Xilinx ZynqMP SHA3 driver
crypto: xilinx - Add Xilinx SHA3 driver
...
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git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld:
"There have been a few important changes to the RNG's crypto, but the
intent for 5.18 has been to shore up the existing design as much as
possible with modern cryptographic functions and proven constructions,
rather than actually changing up anything fundamental to the RNG's
design.
So it's still the same old RNG at its core as before: it still counts
entropy bits, and collects from the various sources with the same
heuristics as before, and so forth. However, the cryptographic
algorithms that transform that entropic data into safe random numbers
have been modernized.
Just as important, if not more, is that the code has been cleaned up
and re-documented. As one of the first drivers in Linux, going back to
1.3.30, its general style and organization was showing its age and
becoming both a maintenance burden and an auditability impediment.
Hopefully this provides a more solid foundation to build on for the
future. I encourage you to open up the file in full, and maybe you'll
remark, "oh, that's what it's doing," and enjoy reading it. That, at
least, is the eventual goal, which this pull begins working toward.
Here's a summary of the various patches in this pull:
- /dev/urandom and /dev/random now do the same thing, per the patch
we discussed on the list. I think this is worth trying out. If it
does appear problematic, I've made sure to keep it standalone and
revertible without any conflicts.
- Fixes and cleanups for numerous integer type problems, locking
issues, and general code quality concerns.
- The input pool's LFSR has been replaced with a cryptographically
secure hash function, which has security and performance benefits
alike, and consequently allows us to count entropy bits linearly.
- The pre-init injection now uses a real hash function too, instead
of an LFSR or vanilla xor.
- The interrupt handler's fast_mix() function now uses one round of
SipHash, rather than the fake crypto that was there before.
- All additions of RDRAND and RDSEED now go through the input pool's
hash function, in part to mitigate ridiculous hypothetical CPU
backdoors, but more so to have a consistent interface for ingesting
entropy that's easy to analyze, making everything happen one way,
instead of a potpourri of different ways.
- The crng now works on per-cpu data, while also being in accordance
with the actual "fast key erasure RNG" design. This allows us to
fix several boot-time race complications associated with the prior
dynamically allocated model, eliminates much locking, and makes our
backtrack protection more robust.
- Batched entropy now erases doled out values so that it's backtrack
resistant.
- Working closely with Sebastian, the interrupt handler no longer
needs to take any locks at all, as we punt the
synchronized/expensive operations to a workqueue. This is
especially nice for PREEMPT_RT, where taking spinlocks in irq
context is problematic. It also makes the handler faster for the
rest of us.
- Also working with Sebastian, we now do the right thing on CPU
hotplug, so that we don't use stale entropy or fail to accumulate
new entropy when CPUs come back online.
- We handle virtual machines that fork / clone / snapshot, using the
"vmgenid" ACPI specification for retrieving a unique new RNG seed,
which we can use to also make WireGuard (and in the future, other
things) safe across VM forks.
- Around boot time, we now try to reseed more often if enough entropy
is available, before settling on the usual 5 minute schedule.
- Last, but certainly not least, the documentation in the file has
been updated considerably"
* tag 'random-5.18-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (60 commits)
random: check for signal and try earlier when generating entropy
random: reseed more often immediately after booting
random: make consistent usage of crng_ready()
random: use SipHash as interrupt entropy accumulator
wireguard: device: clear keys on VM fork
random: provide notifier for VM fork
random: replace custom notifier chain with standard one
random: do not export add_vmfork_randomness() unless needed
virt: vmgenid: notify RNG of VM fork and supply generation ID
ACPI: allow longer device IDs
random: add mechanism for VM forks to reinitialize crng
random: don't let 644 read-only sysctls be written to
random: give sysctl_random_min_urandom_seed a more sensible value
random: block in /dev/urandom
random: do crng pre-init loading in worker rather than irq
random: unify cycles_t and jiffies usage and types
random: cleanup UUID handling
random: only wake up writers after zap if threshold was passed
random: round-robin registers as ulong, not u32
random: clear fast pool, crng, and batches in cpuhp bring up
...
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Clang static analysis reports this issue
ipmi_ssif.c:1731:3: warning: 4th function call
argument is an uninitialized value
dev_info(&ssif_info->client->dev,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 4th parameter is the 'len' variable.
len is only set by a successful call to do_cmd().
Initialize to len 0.
Signed-off-by: Tom Rix <trix@redhat.com>
Message-Id: <20220320135954.2258545-1-trix@redhat.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
|
|
Eliminate anonymous module_init() and module_exit(), which can lead to
confusion or ambiguity when reading System.map, crashes/oops/bugs,
or an initcall_debug log.
Give each of these init and exit functions unique driver-specific
names to eliminate the anonymous names.
Example 1: (System.map)
ffffffff832fc78c t init
ffffffff832fc79e t init
ffffffff832fc8f8 t init
Example 2: (initcall_debug log)
calling init+0x0/0x12 @ 1
initcall init+0x0/0x12 returned 0 after 15 usecs
calling init+0x0/0x60 @ 1
initcall init+0x0/0x60 returned 0 after 2 usecs
calling init+0x0/0x9a @ 1
initcall init+0x0/0x9a returned 0 after 74 usecs
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Amit Shah <amit@kernel.org>
Cc: virtualization@lists.linux-foundation.org
Cc: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20220316192010.19001-3-rdunlap@infradead.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
The gnttab_end_foreign_access() family of functions is taking a
"readonly" parameter, which isn't used. Remove it from the function
parameters.
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220311103429.12845-3-jgross@suse.com
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
|
|
The corresponding API for clk_prepare_enable is clk_disable_unprepare,
other than clk_disable_unprepare.
Fix this by changing clk_disable to clk_disable_unprepare.
Fixes: beca35d05cc2 ("hwrng: nomadik - use clk_prepare_enable()")
Signed-off-by: Miaoqian Lin <linmq006@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
|
|
Rather than waiting a full second in an interruptable waiter before
trying to generate entropy, try to generate entropy first and wait
second. While waiting one second might give an extra second for getting
entropy from elsewhere, we're already pretty late in the init process
here, and whatever else is generating entropy will still continue to
contribute. This has implications on signal handling: we call
try_to_generate_entropy() from wait_for_random_bytes(), and
wait_for_random_bytes() always uses wait_event_interruptible_timeout()
when waiting, since it's called by userspace code in restartable
contexts, where signals can pend. Since try_to_generate_entropy() now
runs first, if a signal is pending, it's necessary for
try_to_generate_entropy() to check for signals, since it won't hit the
wait until after try_to_generate_entropy() has returned. And even before
this change, when entering a busy loop in try_to_generate_entropy(), we
should have been checking to see if any signals are pending, so that a
process doesn't get stuck in that loop longer than expected.
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
In order to chip away at the "premature first" problem, we augment our
existing entropy accounting with more frequent reseedings at boot.
The idea is that at boot, we're getting entropy from various places, and
we're not very sure which of early boot entropy is good and which isn't.
Even when we're crediting the entropy, we're still not totally certain
that it's any good. Since boot is the one time (aside from a compromise)
that we have zero entropy, it's important that we shepherd entropy into
the crng fairly often.
At the same time, we don't want a "premature next" problem, whereby an
attacker can brute force individual bits of added entropy. In lieu of
going full-on Fortuna (for now), we can pick a simpler strategy of just
reseeding more often during the first 5 minutes after boot. This is
still bounded by the 256-bit entropy credit requirement, so we'll skip a
reseeding if we haven't reached that, but in case entropy /is/ coming
in, this ensures that it makes its way into the crng rather rapidly
during these early stages.
Ordinarily we reseed if the previous reseeding is 300 seconds old. This
commit changes things so that for the first 600 seconds of boot time, we
reseed if the previous reseeding is uptime / 2 seconds old. That means
that we'll reseed at the very least double the uptime of the previous
reseeding.
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Rather than sometimes checking `crng_init < 2`, we should always use the
crng_ready() macro, so that should we change anything later, it's
consistent. Additionally, that macro already has a likely() around it,
which means we don't need to open code our own likely() and unlikely()
annotations.
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
The current fast_mix() function is a piece of classic mailing list
crypto, where it just sort of sprung up by an anonymous author without a
lot of real analysis of what precisely it was accomplishing. As an ARX
permutation alone, there are some easily searchable differential trails
in it, and as a means of preventing malicious interrupts, it completely
fails, since it xors new data into the entire state every time. It can't
really be analyzed as a random permutation, because it clearly isn't,
and it can't be analyzed as an interesting linear algebraic structure
either, because it's also not that. There really is very little one can
say about it in terms of entropy accumulation. It might diffuse bits,
some of the time, maybe, we hope, I guess. But for the most part, it
fails to accomplish anything concrete.
As a reminder, the simple goal of add_interrupt_randomness() is to
simply accumulate entropy until ~64 interrupts have elapsed, and then
dump it into the main input pool, which uses a cryptographic hash.
It would be nice to have something cryptographically strong in the
interrupt handler itself, in case a malicious interrupt compromises a
per-cpu fast pool within the 64 interrupts / 1 second window, and then
inside of that same window somehow can control its return address and
cycle counter, even if that's a bit far fetched. However, with a very
CPU-limited budget, actually doing that remains an active research
project (and perhaps there'll be something useful for Linux to come out
of it). And while the abundance of caution would be nice, this isn't
*currently* the security model, and we don't yet have a fast enough
solution to make it our security model. Plus there's not exactly a
pressing need to do that. (And for the avoidance of doubt, the actual
cluster of 64 accumulated interrupts still gets dumped into our
cryptographically secure input pool.)
So, for now we are going to stick with the existing interrupt security
model, which assumes that each cluster of 64 interrupt data samples is
mostly non-malicious and not colluding with an infoleaker. With this as
our goal, we have a few more choices, simply aiming to accumulate
entropy, while discarding the least amount of it.
We know from <https://eprint.iacr.org/2019/198> that random oracles,
instantiated as computational hash functions, make good entropy
accumulators and extractors, which is the justification for using
BLAKE2s in the main input pool. As mentioned, we don't have that luxury
here, but we also don't have the same security model requirements,
because we're assuming that there aren't malicious inputs. A
pseudorandom function instance can approximately behave like a random
oracle, provided that the key is uniformly random. But since we're not
concerned with malicious inputs, we can pick a fixed key, which is not
secret, knowing that "nature" won't interact with a sufficiently chosen
fixed key by accident. So we pick a PRF with a fixed initial key, and
accumulate into it continuously, dumping the result every 64 interrupts
into our cryptographically secure input pool.
For this, we make use of SipHash-1-x on 64-bit and HalfSipHash-1-x on
32-bit, which are already in use in the kernel's hsiphash family of
functions and achieve the same performance as the function they replace.
It would be nice to do two rounds, but we don't exactly have the CPU
budget handy for that, and one round alone is already sufficient.
As mentioned, we start with a fixed initial key (zeros is fine), and
allow SipHash's symmetry breaking constants to turn that into a useful
starting point. Also, since we're dumping the result (or half of it on
64-bit so as to tax our hash function the same amount on all platforms)
into the cryptographically secure input pool, there's no point in
finalizing SipHash's output, since it'll wind up being finalized by
something much stronger. This means that all we need to do is use the
ordinary round function word-by-word, as normal SipHash does.
Simplified, the flow is as follows:
Initialize:
siphash_state_t state;
siphash_init(&state, key={0, 0, 0, 0});
Update (accumulate) on interrupt:
siphash_update(&state, interrupt_data_and_timing);
Dump into input pool after 64 interrupts:
blake2s_update(&input_pool, &state, sizeof(state) / 2);
The result of all of this is that the security model is unchanged from
before -- we assume non-malicious inputs -- yet we now implement that
model with a stronger argument. I would like to emphasize, again, that
the purpose of this commit is to improve the existing design, by making
it analyzable, without changing any fundamental assumptions. There may
well be value down the road in changing up the existing design, using
something cryptographically strong, or simply using a ring buffer of
samples rather than having a fast_mix() at all, or changing which and
how much data we collect each interrupt so that we can use something
linear, or a variety of other ideas. This commit does not invalidate the
potential for those in the future.
For example, in the future, if we're able to characterize the data we're
collecting on each interrupt, we may be able to inch toward information
theoretic accumulators. <https://eprint.iacr.org/2021/523> shows that `s
= ror32(s, 7) ^ x` and `s = ror64(s, 19) ^ x` make very good
accumulators for 2-monotone distributions, which would apply to
timestamp counters, like random_get_entropy() or jiffies, but would not
apply to our current combination of the two values, or to the various
function addresses and register values we mix in. Alternatively,
<https://eprint.iacr.org/2021/1002> shows that max-period linear
functions with no non-trivial invariant subspace make good extractors,
used in the form `s = f(s) ^ x`. However, this only works if the input
data is both identical and independent, and obviously a collection of
address values and counters fails; so it goes with theoretical papers.
Future directions here may involve trying to characterize more precisely
what we actually need to collect in the interrupt handler, and building
something specific around that.
However, as mentioned, the morass of data we're gathering at the
interrupt handler presently defies characterization, and so we use
SipHash for now, which works well and performs well.
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Drivers such as WireGuard need to learn when VMs fork in order to clear
sessions. This commit provides a simple notifier_block for that, with a
register and unregister function. When no VM fork detection is compiled
in, this turns into a no-op, similar to how the power notifier works.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
We previously rolled our own randomness readiness notifier, which only
has two users in the whole kernel. Replace this with a more standard
atomic notifier block that serves the same purpose with less code. Also
unexport the symbols, because no modules use it, only unconditional
builtins. The only drawback is that it's possible for a notification
handler returning the "stop" code to prevent further processing, but
given that there are only two users, and that we're unexporting this
anyway, that doesn't seem like a significant drawback for the
simplification we receive here.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
Since add_vmfork_randomness() is only called from vmgenid.o, we can
guard it in CONFIG_VMGENID, similarly to how we do with
add_disk_randomness() and CONFIG_BLOCK. If we ever have multiple things
calling into add_vmfork_randomness(), we can add another shared Kconfig
symbol for that, but for now, this is good enough. Even though
add_vmfork_randomess() is a pretty small function, removing it means
that there are only calls to crng_reseed(false) and none to
crng_reseed(true), which means the compiler can constant propagate the
false, removing branches from crng_reseed() and its descendants.
Additionally, we don't even need the symbol to be exported if
CONFIG_VMGENID is not a module, so conditionalize that too.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
|
When a VM forks, we must immediately mix in additional information to
the stream of random output so that two forks or a rollback don't
produce the same stream of random numbers, which could have catastrophic
cryptographic consequences. This commit adds a simple API, add_vmfork_
randomness(), for that, by force reseeding the crng.
This has the added benefit of also draining the entropy pool and setting
its timer back, so that any old entropy that was there prior -- which
could have already been used by a different fork, or generally gone
stale -- does not contribute to the accounting of the next 256 bits.
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jann Horn <jannh@google.com>
Cc: Eric Biggers <ebiggers@google.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
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We leave around these old sysctls for compatibility, and we keep them
"writable" for compatibility, but even after writing, we should keep
reporting the same value. This is consistent with how userspaces tend to
use sysctl_random_write_wakeup_bits, writing to it, and then later
reading from it and using the value.
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
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This isn't used by anything or anywhere, but we can't delete it due to
compatibility. So at least give it the correct value of what it's
supposed to be instead of a garbage one.
Cc: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
|
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This topic has come up countless times, and usually doesn't go anywhere.
This time I thought I'd bring it up with a slightly narrower focus,
updated for some developments over the last three years: we finally can
make /dev/urandom always secure, in light of the fact that our RNG is
now always seeded.
Ever since Linus' 50ee7529ec45 ("random: try to actively add entropy
rather than passively wait for it"), the RNG does a haveged-style jitter
dance around the scheduler, in order to produce entropy (and credit it)
for the case when we're stuck in wait_for_random_bytes(). How ever you
feel about the Linus Jitter Dance is beside the point: it's been there
for three years and usually gets the RNG initialized in a second or so.
As a matter of fact, this is what happens currently when people use
getrandom(). It's already there and working, and most people have been
using it for years without realizing.
So, given that the kernel has grown this mechanism for seeding itself
from nothing, and that this procedure happens pretty fast, maybe there's
no point any longer in having /dev/urandom give insecure bytes. In the
past we didn't want the boot process to deadlock, which was
understandable. But now, in the worst case, a second goes by, and the
problem is resolved. It seems like maybe we're finally at a point when
we can get rid of the infamous "urandom read hole".
The one slight drawback is that the Linus Jitter Dance relies on random_
get_entropy() being implemented. The first lines of try_to_generate_
entropy() are:
stack.now = random_get_entropy();
if (stack.now == random_get_entropy())
return;
On most platforms, random_get_entropy() is simply aliased to get_cycles().
The number of machines without a cycle counter or some other
implementation of random_get_entropy() in 2022, which can also run a
mainline kernel, and at the same time have a both broken and out of date
userspace that relies on /dev/urandom never blocking at boot is thought
to be exceedingly low. And to be clear: those museum pieces without
cycle counters will continue to run Linux just fine, and even
/dev/urandom will be operable just like before; the RNG just needs to be
seeded first through the usual means, which should already be the case
now.
On systems that really do want unseeded randomness, we already offer
getrandom(GRND_INSECURE), which is in use by, e.g., systemd for seeding
their hash tables at boot. Nothing in this commit would affect
GRND_INSECURE, and it remains the means of getting those types of random
numbers.
This patch goes a long way toward eliminating a long overdue userspace
crypto footgun. After several decades of endless user confusion, we will
finally be able to say, "use any single one of our random interfaces and
you'll be fine. They're all the same. It doesn't matter." And that, I
think, is really something. Finally all of those blog posts and
disagreeing forums and contradictory articles will all become correct
about whatever they happened to recommend, and along with it, a whole
class of vulnerabilities eliminated.
With very minimal downside, we're finally in a position where we can
make this change.
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Guo Ren <guoren@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Joshua Kinard <kumba@gentoo.org>
Cc: David Laight <David.Laight@aculab.com>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Cc: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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As part of the series conversion to remove nested TPM operations:
https://lore.kernel.org/all/20190205224723.19671-1-jarkko.sakkinen@linux.intel.com/
exposure of the chip->tpm_mutex was removed from much of the upper
level code. In this conversion, tpm2_del_space() was missed. This
didn't matter much because it's usually called closely after a
converted operation, so there's only a very tiny race window where the
chip can be removed before the space flushing is done which causes a
NULL deref on the mutex. However, there are reports of this window
being hit in practice, so fix this by converting tpm2_del_space() to
use tpm_try_get_ops(), which performs all the teardown checks before
acquring the mutex.
Cc: stable@vger.kernel.org # 5.4.x
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
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The following sequence of operations results in a refcount warning:
1. Open device /dev/tpmrm.
2. Remove module tpm_tis_spi.
3. Write a TPM command to the file descriptor opened at step 1.
------------[ cut here ]------------
WARNING: CPU: 3 PID: 1161 at lib/refcount.c:25 kobject_get+0xa0/0xa4
refcount_t: addition on 0; use-after-free.
Modules linked in: tpm_tis_spi tpm_tis_core tpm mdio_bcm_unimac brcmfmac
sha256_generic libsha256 sha256_arm hci_uart btbcm bluetooth cfg80211 vc4
brcmutil ecdh_generic ecc snd_soc_core crc32_arm_ce libaes
raspberrypi_hwmon ac97_bus snd_pcm_dmaengine bcm2711_thermal snd_pcm
snd_timer genet snd phy_generic soundcore [last unloaded: spi_bcm2835]
CPU: 3 PID: 1161 Comm: hold_open Not tainted 5.10.0ls-main-dirty #2
Hardware name: BCM2711
[<c0410c3c>] (unwind_backtrace) from [<c040b580>] (show_stack+0x10/0x14)
[<c040b580>] (show_stack) from [<c1092174>] (dump_stack+0xc4/0xd8)
[<c1092174>] (dump_stack) from [<c0445a30>] (__warn+0x104/0x108)
[<c0445a30>] (__warn) from [<c0445aa8>] (warn_slowpath_fmt+0x74/0xb8)
[<c0445aa8>] (warn_slowpath_fmt) from [<c08435d0>] (kobject_get+0xa0/0xa4)
[<c08435d0>] (kobject_get) from [<bf0a715c>] (tpm_try_get_ops+0x14/0x54 [tpm])
[<bf0a715c>] (tpm_try_get_ops [tpm]) from [<bf0a7d6c>] (tpm_common_write+0x38/0x60 [tpm])
[<bf0a7d6c>] (tpm_common_write [tpm]) from [<c05a7ac0>] (vfs_write+0xc4/0x3c0)
[<c05a7ac0>] (vfs_write) from [<c05a7ee4>] (ksys_write+0x58/0xcc)
[<c05a7ee4>] (ksys_write) from [<c04001a0>] (ret_fast_syscall+0x0/0x4c)
Exception stack(0xc226bfa8 to 0xc226bff0)
bfa0: 00000000 000105b4 00000003 beafe664 00000014 00000000
bfc0: 00000000 000105b4 000103f8 00000004 00000000 00000000 b6f9c000 beafe684
bfe0: 0000006c beafe648 0001056c b6eb6944
---[ end trace d4b8409def9b8b1f ]---
The reason for this warning is the attempt to get the chip->dev reference
in tpm_common_write() although the reference counter is already zero.
Since commit 8979b02aaf1d ("tpm: Fix reference count to main device") the
extra reference used to prevent a premature zero counter is never taken,
because the required TPM_CHIP_FLAG_TPM2 flag is never set.
Fix this by moving the TPM 2 character device handling from
tpm_chip_alloc() to tpm_add_char_device() which is called at a later point
in time when the flag has been set in case of TPM2.
Commit fdc915f7f719 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
already introduced function tpm_devs_release() to release the extra
reference but did not implement the required put on chip->devs that results
in the call of this function.
Fix this by putting chip->devs in tpm_chip_unregister().
Finally move the new implementation for the TPM 2 handling into a new
function to avoid multiple checks for the TPM_CHIP_FLAG_TPM2 flag in the
good case and error cases.
Cc: stable@vger.kernel.org
Fixes: fdc915f7f719 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
Fixes: 8979b02aaf1d ("tpm: Fix reference count to main device")
Co-developed-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
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Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worse scenario, could lead to heap overflows.
Also, address the following sparse warning:
drivers/char/tpm/xen-tpmfront.c:131:16: warning: using sizeof on a flexible structure
Link: https://github.com/KSPP/linux/issues/160
Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
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When an invalid (non existing) handle is used in a TPM command,
that uses the resource manager interface (/dev/tpmrm0) the resource
manager tries to load it from its internal cache, but fails and
the tpm_dev_transmit returns an -EINVAL error to the caller.
The existing async handler doesn't handle these error cases
currently and the condition in the poll handler never returns
mask with EPOLLIN set.
The result is that the poll call blocks and the application gets stuck
until the user_read_timer wakes it up after 120 sec.
Change the tpm_dev_async_work function to handle error conditions
returned from tpm_dev_transmit they are also reflected in the poll mask
and a correct error code could passed back to the caller.
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: <linux-integrity@vger.kernel.org>
Cc: <stable@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Fixes: 9e1b74a63f77 ("tpm: add support for nonblocking operation")
Tested-by: Jarkko Sakkinen<jarkko@kernel.org>
Signed-off-by: Tadeusz Struk <tstruk@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
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A common pattern for device reset is currently:
vdev->config->reset(vdev);
.. cleanup ..
reset prevents new interrupts from arriving and waits for interrupt
handlers to finish.
However if - as is common - the handler queues a work request which is
flushed during the cleanup stage, we have code adding buffers / trying
to get buffers while device is reset. Not good.
This was reproduced by running
modprobe virtio_console
modprobe -r virtio_console
in a loop.
Fix this up by calling virtio_break_device + flush before reset.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1786239
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Fix following coccicheck warning:
./drivers/char/hw_random/cavium-rng-vf.c:182:17-20: ERROR:
pdev is NULL but dereferenced.
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Reviewed-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Remove extra line.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Add runtime PM support.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Use __maybe_unused and pm_ptr() for pm ops.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Move set of TRNG_HALFR in atmel_trng_init() as this function is
also called on resume path. In case of SAMA7G5 where backup and
self-refresh PM mode is available most of the SoC parts are
powered of (including TRNG) when entering suspend. In that case
on resuming path TRNG_HALFR should also be re-configured.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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s/atmel_trng_disable/atmel_trng_cleanup/g and
s/atmel_trng_enable/atmel_trng_init/g to cope with
struct hwrng::{init, cleanup} members.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Call atmel_trng_disable() on failure path of probe.
Fixes: a1fa98d8116f ("hwrng: atmel - disable TRNG during suspend")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Add wait for ready support on read.
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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