linux-stable.git/drivers/char/hw_random, branch linux-6.3.y

hwrng: st - keep clock enabled while hwrng is registered

2023-07-11T17:39:50+00:00

[ Upstream commit 501e197a02d4aef157f53ba3a0b9049c3e52fedc ]

The st-rng driver uses devres to register itself with the hwrng core,
the driver will be unregistered from hwrng when its device goes out of
scope. This happens after the driver's remove function is called.

However, st-rng's clock is disabled in the remove function. There's a
short timeframe where st-rng is still registered with the hwrng core
although its clock is disabled. I suppose the clock must be active to
access the hardware and serve requests from the hwrng core.

Switch to devm_clk_get_enabled and let devres disable the clock and
unregister the hwrng. This avoids the race condition.

Fixes: 3e75241be808 ("hwrng: drivers - Use device-managed registration API")
Signed-off-by: Martin Kaiser 
Signed-off-by: Herbert Xu 
Signed-off-by: Sasha Levin

hwrng: virtio - Fix race on data_avail and actual data

2023-07-11T17:39:49+00:00

[ Upstream commit ac52578d6e8d300dd50f790f29a24169b1edd26c ]

The virtio rng device kicks off a new entropy request whenever the
data available reaches zero.  When a new request occurs at the end
of a read operation, that is, when the result of that request is
only needed by the next reader, then there is a race between the
writing of the new data and the next reader.

This is because there is no synchronisation whatsoever between the
writer and the reader.

Fix this by writing data_avail with smp_store_release and reading
it with smp_load_acquire when we first enter read.  The subsequent
reads are safe because they're either protected by the first load
acquire, or by the completion mechanism.

Also remove the redundant zeroing of data_idx in random_recv_done
(data_idx must already be zero at this point) and data_avail in
request_entropy (ditto).

Reported-by: syzbot+726dc8c62c3536431ceb@syzkaller.appspotmail.com
Fixes: f7f510ec1957 ("virtio: An entropy device, as suggested by hpa.")
Signed-off-by: Herbert Xu 
Acked-by: Michael S. Tsirkin 
Signed-off-by: Herbert Xu 
Signed-off-by: Sasha Levin

hwrng: starfive - Enable compile testing

2023-02-03T04:55:59+00:00

Enable compile testing for jh7110.  Also remove the dependency on
HW_RANDOM.

Signed-off-by: Herbert Xu 
Reviewed-by: Conor Dooley 
Reviewed-by: Jia Jie Ho 
Signed-off-by: Herbert Xu

hwrng: starfive - Add TRNG driver for StarFive SoC

2023-01-27T10:58:09+00:00

This adds driver support for the hardware random number generator in
Starfive SoCs and adds StarFive TRNG entry to MAINTAINERS.

Co-developed-by: Jenny Zhang 
Signed-off-by: Jenny Zhang 
Signed-off-by: Jia Jie Ho 
Signed-off-by: Herbert Xu

random: do not include from random.h

2022-12-20T02:13:45+00:00

The  header is a random.c private detail, not
something to be called by other code. As such, don't make it
automatically available by way of random.h.

Cc: Michael Ellerman 
Acked-by: Heiko Carstens 
Reviewed-by: Christophe Leroy 
Signed-off-by: Jason A. Donenfeld

Merge tag 'v6.2-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

2022-12-14T20:31:09+00:00

Pull crypto updates from Herbert Xu:
 "API:
   - Optimise away self-test overhead when they are disabled
   - Support symmetric encryption via keyring keys in af_alg
   - Flip hwrng default_quality, the default is now maximum entropy

  Algorithms:
   - Add library version of aesgcm
   - CFI fixes for assembly code
   - Add arm/arm64 accelerated versions of sm3/sm4

  Drivers:
   - Remove assumption on arm64 that kmalloc is DMA-aligned
   - Fix selftest failures in rockchip
   - Add support for RK3328/RK3399 in rockchip
   - Add deflate support in qat
   - Merge ux500 into stm32
   - Add support for TEE for PCI ID 0x14CA in ccp
   - Add mt7986 support in mtk
   - Add MaxLinear platform support in inside-secure
   - Add NPCM8XX support in npcm"

* tag 'v6.2-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (184 commits)
  crypto: ux500/cryp - delete driver
  crypto: stm32/cryp - enable for use with Ux500
  crypto: stm32 - enable drivers to be used on Ux500
  dt-bindings: crypto: Let STM32 define Ux500 CRYP
  hwrng: geode - Fix PCI device refcount leak
  hwrng: amd - Fix PCI device refcount leak
  crypto: qce - Set DMA alignment explicitly
  crypto: octeontx2 - Set DMA alignment explicitly
  crypto: octeontx - Set DMA alignment explicitly
  crypto: keembay - Set DMA alignment explicitly
  crypto: safexcel - Set DMA alignment explicitly
  crypto: hisilicon/hpre - Set DMA alignment explicitly
  crypto: chelsio - Set DMA alignment explicitly
  crypto: ccree - Set DMA alignment explicitly
  crypto: ccp - Set DMA alignment explicitly
  crypto: cavium - Set DMA alignment explicitly
  crypto: img-hash - Fix variable dereferenced before check 'hdev->req'
  crypto: arm64/ghash-ce - use frame_push/pop macros consistently
  crypto: arm64/crct10dif - use frame_push/pop macros consistently
  crypto: arm64/aes-modes - use frame_push/pop macros consistently
  ...

hwrng: geode - Fix PCI device refcount leak

2022-12-09T10:45:00+00:00

for_each_pci_dev() is implemented by pci_get_device(). The comment of
pci_get_device() says that it will increase the reference count for the
returned pci_dev and also decrease the reference count for the input
pci_dev @from if it is not NULL.

If we break for_each_pci_dev() loop with pdev not NULL, we need to call
pci_dev_put() to decrease the reference count. We add a new struct
'amd_geode_priv' to record pointer of the pci_dev and membase, and then
add missing pci_dev_put() for the normal and error path.

Fixes: ef5d862734b8 ("[PATCH] Add Geode HW RNG driver")
Signed-off-by: Xiongfeng Wang 
Signed-off-by: Herbert Xu

hwrng: amd - Fix PCI device refcount leak

2022-12-09T10:45:00+00:00

for_each_pci_dev() is implemented by pci_get_device(). The comment of
pci_get_device() says that it will increase the reference count for the
returned pci_dev and also decrease the reference count for the input
pci_dev @from if it is not NULL.

If we break for_each_pci_dev() loop with pdev not NULL, we need to call
pci_dev_put() to decrease the reference count. Add the missing
pci_dev_put() for the normal and error path.

Fixes: 96d63c0297cc ("[PATCH] Add AMD HW RNG driver")
Signed-off-by: Xiongfeng Wang 
Signed-off-by: Herbert Xu

hwrng: stm32 - rename readl return value

2022-11-18T08:59:34+00:00

Use a more meaningful name for the readl return value variable.

Link: https://lore.kernel.org/all/Y1J3QwynPFIlfrIv@loth.rohan.me.apana.org.au/

Signed-off-by: Tomas Marek 
Signed-off-by: Herbert Xu

hwrng: core - treat default_quality as a maximum and default to 1024

2022-11-18T08:59:34+00:00

Most hw_random devices return entropy which is assumed to be of full
quality, but driver authors don't bother setting the quality knob. Some
hw_random devices return less than full quality entropy, and then driver
authors set the quality knob. Therefore, the entropy crediting should be
opt-out rather than opt-in per-driver, to reflect the actual reality on
the ground.

For example, the two Raspberry Pi RNG drivers produce full entropy
randomness, and both EDK2 and U-Boot's drivers for these treat them as
such. The result is that EFI then uses these numbers and passes the to
Linux, and Linux credits them as boot, thereby initializing the RNG.
Yet, in Linux, the quality knob was never set to anything, and so on the
chance that Linux is booted without EFI, nothing is ever credited.
That's annoying.

The same pattern appears to repeat itself throughout various drivers. In
fact, very very few drivers have bothered setting quality=1024.

Looking at the git history of existing drivers and corresponding mailing
list discussion, this conclusion tracks. There's been a decent amount of
discussion about drivers that set quality < 1024 -- somebody read and
interepreted a datasheet, or made some back of the envelope calculation
somehow. But there's been very little, if any, discussion about most
drivers where the quality is just set to 1024 or unset (or set to 1000
when the authors misunderstood the API and assumed it was base-10 rather
than base-2); in both cases the intent was fairly clear of, "this is a
hardware random device; it's fine."

So let's invert this logic. A hw_random struct's quality knob now
controls the maximum quality a driver can produce, or 0 to specify 1024.
Then, the module-wide switch called "default_quality" is changed to
represent the maximum quality of any driver. By default it's 1024, and
the quality of any particular driver is then given by:

    min(default_quality, rng->quality ?: 1024);

This way, the user can still turn this off for weird reasons (and we can
replace whatever driver-specific disabling hacks existed in the past),
yet we get proper crediting for relevant RNGs.

Cc: Dominik Brodowski 
Cc: Ard Biesheuvel 
Cc: Herbert Xu 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Herbert Xu