kernel/linux.git/drivers/char/hw_random/core.c, branch v5.10.264

hwrng: core - Fix page fault dead lock on mmap-ed hwrng

2024-02-23T07:41:52+00:00

commit 78aafb3884f6bc6636efcc1760c891c8500b9922 upstream. There is a dead-lock in the hwrng device read path. This triggers when the user reads from /dev/hwrng into memory also mmap-ed from /dev/hwrng. The resulting page fault triggers a recursive read which then dead-locks. Fix this by using a stack buffer when calling copy_to_user. Reported-by: Edward Adam Davis Reported-by: syzbot+c52ab18308964d248092@syzkaller.appspotmail.com Fixes: 9996508b3353 ("hwrng: core - Replace u32 in driver API with byte array") Cc: Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman

random: pull add_hwgenerator_randomness() declaration into random.h

2022-05-30T07:33:36+00:00

commit b777c38239fec5a528e59f55b379e31b1a187524 upstream. add_hwgenerator_randomness() is a function implemented and documented inside of random.c. It is the way that hardware RNGs push data into it. Therefore, it should be declared in random.h. Otherwise sparse complains with: random.c:1137:6: warning: symbol 'add_hwgenerator_randomness' was not declared. Should it be static? The alternative would be to include hw_random.h into random.c, but that wouldn't really be good for anything except slowing down compile time. Cc: Matt Mackall Cc: Theodore Ts'o Acked-by: Herbert Xu Reviewed-by: Eric Biggers Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman

hwrng: core - remove redundant initialization of variable ret

2020-07-31T08:25:29+00:00

The variable ret is being initialized with a value that is never read and it is being updated later with a new value. The initialization is redundant and can be removed. Addresses-Coverity: ("Unused value") Signed-off-by: Colin Ian King Signed-off-by: Herbert Xu

Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

2019-11-26T03:49:58+00:00

Pull crypto updates from Herbert Xu: "API: - Add library interfaces of certain crypto algorithms for WireGuard - Remove the obsolete ablkcipher and blkcipher interfaces - Move add_early_randomness() out of rng_mutex Algorithms: - Add blake2b shash algorithm - Add blake2s shash algorithm - Add curve25519 kpp algorithm - Implement 4 way interleave in arm64/gcm-ce - Implement ciphertext stealing in powerpc/spe-xts - Add Eric Biggers's scalar accelerated ChaCha code for ARM - Add accelerated 32r2 code from Zinc for MIPS - Add OpenSSL/CRYPTOGRAMS poly1305 implementation for ARM and MIPS Drivers: - Fix entropy reading failures in ks-sa - Add support for sam9x60 in atmel - Add crypto accelerator for amlogic GXL - Add sun8i-ce Crypto Engine - Add sun8i-ss cryptographic offloader - Add a host of algorithms to inside-secure - Add NPCM RNG driver - add HiSilicon HPRE accelerator - Add HiSilicon TRNG driver" * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (285 commits) crypto: vmx - Avoid weird build failures crypto: lib/chacha20poly1305 - use chacha20_crypt() crypto: x86/chacha - only unregister algorithms if registered crypto: chacha_generic - remove unnecessary setkey() functions crypto: amlogic - enable working on big endian kernel crypto: sun8i-ce - enable working on big endian crypto: mips/chacha - select CRYPTO_SKCIPHER, not CRYPTO_BLKCIPHER hwrng: ks-sa - Enable COMPILE_TEST crypto: essiv - remove redundant null pointer check before kfree crypto: atmel-aes - Change data type for "lastc" buffer crypto: atmel-tdes - Set the IV after {en,de}crypt crypto: sun4i-ss - fix big endian issues crypto: sun4i-ss - hide the Invalid keylen message crypto: sun4i-ss - use crypto_ahash_digestsize crypto: sun4i-ss - remove dependency on not 64BIT crypto: sun4i-ss - Fix 64-bit size_t warnings on sun4i-ss-hash.c MAINTAINERS: Add maintainer for HiSilicon SEC V2 driver crypto: hisilicon - add DebugFS for HiSilicon SEC Documentation: add DebugFS doc for HiSilicon SEC crypto: hisilicon - add SRIOV for HiSilicon SEC ...

Revert "hwrng: core - Freeze khwrng thread during suspend"

2019-11-17T00:48:17+00:00

This reverts commit 03a3bb7ae631 ("hwrng: core - Freeze khwrng thread during suspend"), ff296293b353 ("random: Support freezable kthreads in add_hwgenerator_randomness()") and 59b569480dc8 ("random: Use wait_event_freezable() in add_hwgenerator_randomness()"). These patches introduced regressions and we need more time to get them ready for mainline. Signed-off-by: Herbert Xu

hwrng: core - Fix use-after-free warning in hwrng_register()

2019-10-23T08:47:00+00:00

Commit daae28debcb0 has moved add_early_randomness() out of the rng_mutex and tries to protect the reference of the new rng device by incrementing the reference counter. But in hwrng_register(), the function can be called with a new device that is not set as the current_rng device and the reference has not been initialized. This patch fixes the problem by not using the reference counter when the device is not the current one: the reference counter is only meaningful in the case of the current rng device and a device is not used if it is not the current one (except in hwrng_register()) The problem has been reported by Marek Szyprowski on ARM 32bit Exynos5420-based Chromebook Peach-Pit board: WARNING: CPU: 3 PID: 1 at lib/refcount.c:156 hwrng_register+0x13c/0x1b4 refcount_t: increment on 0; use-after-free. Modules linked in: CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc1-00061-gdaae28debcb0 Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [] (show_stack) from [] (dump_stack+0xa8/0xd4) [] (dump_stack) from [] (__warn+0xf4/0x10c) [] (__warn) from [] (warn_slowpath_fmt+0x74/0xb8) [] (warn_slowpath_fmt) from [] (hwrng_register+0x13c/0x1b4) [] (hwrng_register) from [] (tpm_chip_register+0xc4/0x274) ... Reported-by: Marek Szyprowski Fixes: daae28debcb0 ("hwrng: core - move add_early_randomness() out of rng_mutex") Tested-by: Marek Szyprowski Signed-off-by: Laurent Vivier Signed-off-by: Herbert Xu

hwrng: core - move add_early_randomness() out of rng_mutex

2019-10-10T12:36:31+00:00

add_early_randomness() is called every time a new rng backend is added and every time it is set as the current rng provider. add_early_randomness() is called from functions locking rng_mutex, and if it hangs all the hw_random framework hangs: we can't read sysfs, add or remove a backend. This patch move add_early_randomness() out of the rng_mutex zone. It only needs the reading_mutex. Signed-off-by: Laurent Vivier Signed-off-by: Herbert Xu

hwrng: core - don't wait on add_early_randomness()

2019-09-20T13:05:33+00:00

add_early_randomness() is called by hwrng_register() when the hardware is added. If this hardware and its module are present at boot, and if there is no data available the boot hangs until data are available and can't be interrupted. For instance, in the case of virtio-rng, in some cases the host can be not able to provide enough entropy for all the guests. We can have two easy ways to reproduce the problem but they rely on misconfiguration of the hypervisor or the egd daemon: - if virtio-rng device is configured to connect to the egd daemon of the host but when the virtio-rng driver asks for data the daemon is not connected, - if virtio-rng device is configured to connect to the egd daemon of the host but the egd daemon doesn't provide data. The guest kernel will hang at boot until the virtio-rng driver provides enough data. To avoid that, call rng_get_data() in non-blocking mode (wait=0) from add_early_randomness(). Signed-off-by: Laurent Vivier Fixes: d9e797261933 ("hwrng: add randomness to system from rng...") Cc: Reviewed-by: Theodore Ts'o Signed-off-by: Herbert Xu

hwrng: core - Freeze khwrng thread during suspend

2019-08-15T11:52:13+00:00

The hwrng_fill() function can run while devices are suspending and resuming. If the hwrng is behind a bus such as i2c or SPI and that bus is suspended, the hwrng may hang the bus while attempting to add some randomness. It's been observed on ChromeOS devices with suspend-to-idle (s2idle) and an i2c based hwrng that this kthread may run and ask the hwrng device for randomness before the i2c bus has been resumed. Let's make this kthread freezable so that we don't try to touch the hwrng during suspend/resume. This ensures that we can't cause the hwrng backing driver to get into a bad state because the device is guaranteed to be resumed before the hwrng kthread is thawed. Cc: Andrey Pronin Cc: Duncan Laurie Cc: Jason Gunthorpe Cc: Arnd Bergmann Cc: Greg Kroah-Hartman Cc: Guenter Roeck Cc: Alexander Steffen Signed-off-by: Stephen Boyd Signed-off-by: Herbert Xu

docs: admin-guide: add a series of orphaned documents

2019-07-15T14:03:02+00:00

There are lots of documents that belong to the admin-guide but are on random places (most under Documentation root dir). Move them to the admin guide. Signed-off-by: Mauro Carvalho Chehab Acked-by: Alexandre Belloni Acked-by: Bartlomiej Zolnierkiewicz