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2022-02-21random: get rid of secondary crngsJason A. Donenfeld1-172/+53
As the comment said, this is indeed a "hack". Since it was introduced, it's been a constant state machine nightmare, with lots of subtle early boot issues and a wildly complex set of machinery to keep everything in sync. Rather than continuing to play whack-a-mole with this approach, this commit simply removes it entirely. This commit is preparation for "random: use simpler fast key erasure flow on per-cpu keys" in this series, which introduces a simpler (and faster) mechanism to accomplish the same thing. Cc: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21random: use RDSEED instead of RDRAND in entropy extractionJason A. Donenfeld1-13/+9
When /dev/random was directly connected with entropy extraction, without any expansion stage, extract_buf() was called for every 10 bytes of data read from /dev/random. For that reason, RDRAND was used rather than RDSEED. At the same time, crng_reseed() was still only called every 5 minutes, so there RDSEED made sense. Those olden days were also a time when the entropy collector did not use a cryptographic hash function, which meant most bets were off in terms of real preimage resistance. For that reason too it didn't matter _that_ much whether RDSEED was mixed in before or after entropy extraction; both choices were sort of bad. But now we have a cryptographic hash function at work, and with that we get real preimage resistance. We also now only call extract_entropy() every 5 minutes, rather than every 10 bytes. This allows us to do two important things. First, we can switch to using RDSEED in extract_entropy(), as Dominik suggested. Second, we can ensure that RDSEED input always goes into the cryptographic hash function with other things before being used directly. This eliminates a category of attacks in which the CPU knows the current state of the crng and knows that we're going to xor RDSEED into it, and so it computes a malicious RDSEED. By going through our hash function, it would require the CPU to compute a preimage on the fly, which isn't going to happen. Cc: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Suggested-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21random: fix locking in crng_fast_load()Dominik Brodowski1-2/+3
crng_init is protected by primary_crng->lock, so keep holding that lock when incrementing crng_init from 0 to 1 in crng_fast_load(). The call to pr_notice() can wait until the lock is released; this code path cannot be reached twice, as crng_fast_load() aborts early if crng_init > 0. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Reviewed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21random: remove batched entropy lockingJason A. Donenfeld1-27/+28
Rather than use spinlocks to protect batched entropy, we can instead disable interrupts locally, since we're dealing with per-cpu data, and manage resets with a basic generation counter. At the same time, we can't quite do this on PREEMPT_RT, where we still want spinlocks-as- mutexes semantics. So we use a local_lock_t, which provides the right behavior for each. Because this is a per-cpu lock, that generation counter is still doing the necessary CPU-to-CPU communication. This should improve performance a bit. It will also fix the linked splat that Jonathan received with a PROVE_RAW_LOCK_NESTING=y. Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Reviewed-by: Eric Biggers <ebiggers@google.com> Suggested-by: Andy Lutomirski <luto@kernel.org> Reported-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Tested-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net> Link: https://lore.kernel.org/lkml/YfMa0QgsjCVdRAvJ@latitude/ Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21random: remove use_input_pool parameter from crng_reseed()Eric Biggers1-6/+6
The primary_crng is always reseeded from the input_pool, while the NUMA crngs are always reseeded from the primary_crng. Remove the redundant 'use_input_pool' parameter from crng_reseed() and just directly check whether the crng is the primary_crng. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21random: make credit_entropy_bits() always safeJason A. Donenfeld1-20/+9
This is called from various hwgenerator drivers, so rather than having one "safe" version for userspace and one "unsafe" version for the kernel, just make everything safe; the checks are cheap and sensible to have anyway. Reported-by: Sultan Alsawaf <sultan@kerneltoast.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21random: always wake up entropy writers after extractionJason A. Donenfeld1-22/+11
Now that POOL_BITS == POOL_MIN_BITS, we must unconditionally wake up entropy writers after every extraction. Therefore there's no point of write_wakeup_threshold, so we can move it to the dustbin of unused compatibility sysctls. While we're at it, we can fix a small comparison where we were waking up after <= min rather than < min. Cc: Theodore Ts'o <tytso@mit.edu> Suggested-by: Eric Biggers <ebiggers@kernel.org> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21random: use linear min-entropy accumulation creditingJason A. Donenfeld1-94/+20
30e37ec516ae ("random: account for entropy loss due to overwrites") assumed that adding new entropy to the LFSR pool probabilistically cancelled out old entropy there, so entropy was credited asymptotically, approximating Shannon entropy of independent sources (rather than a stronger min-entropy notion) using 1/8th fractional bits and replacing a constant 2-2/√𝑒 term (~0.786938) with 3/4 (0.75) to slightly underestimate it. This wasn't superb, but it was perhaps better than nothing, so that's what was done. Which entropy specifically was being cancelled out and how much precisely each time is hard to tell, though as I showed with the attack code in my previous commit, a motivated adversary with sufficient information can actually cancel out everything. Since we're no longer using an LFSR for entropy accumulation, this probabilistic cancellation is no longer relevant. Rather, we're now using a computational hash function as the accumulator and we've switched to working in the random oracle model, from which we can now revisit the question of min-entropy accumulation, which is done in detail in <https://eprint.iacr.org/2019/198>. Consider a long input bit string that is built by concatenating various smaller independent input bit strings. Each one of these inputs has a designated min-entropy, which is what we're passing to credit_entropy_bits(h). When we pass the concatenation of these to a random oracle, it means that an adversary trying to receive back the same reply as us would need to become certain about each part of the concatenated bit string we passed in, which means becoming certain about all of those h values. That means we can estimate the accumulation by simply adding up the h values in calls to credit_entropy_bits(h); there's no probabilistic cancellation at play like there was said to be for the LFSR. Incidentally, this is also what other entropy accumulators based on computational hash functions do as well. So this commit replaces credit_entropy_bits(h) with essentially `total = min(POOL_BITS, total + h)`, done with a cmpxchg loop as before. What if we're wrong and the above is nonsense? It's not, but let's assume we don't want the actual _behavior_ of the code to change much. Currently that behavior is not extracting from the input pool until it has 128 bits of entropy in it. With the old algorithm, we'd hit that magic 128 number after roughly 256 calls to credit_entropy_bits(1). So, we can retain more or less the old behavior by waiting to extract from the input pool until it hits 256 bits of entropy using the new code. For people concerned about this change, it means that there's not that much practical behavioral change. And for folks actually trying to model the behavior rigorously, it means that we have an even higher margin against attacks. Cc: Theodore Ts'o <tytso@mit.edu> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21random: simplify entropy debitingJason A. Donenfeld1-70/+21
Our pool is 256 bits, and we only ever use all of it or don't use it at all, which is decided by whether or not it has at least 128 bits in it. So we can drastically simplify the accounting and cmpxchg loop to do exactly this. While we're at it, we move the minimum bit size into a constant so it can be shared between the two places where it matters. The reason we want any of this is for the case in which an attacker has compromised the current state, and then bruteforces small amounts of entropy added to it. By demanding a particular minimum amount of entropy be present before reseeding, we make that bruteforcing difficult. Note that this rationale no longer includes anything about /dev/random blocking at the right moment, since /dev/random no longer blocks (except for at ~boot), but rather uses the crng. In a former life, /dev/random was different and therefore required a more nuanced account(), but this is no longer. Behaviorally, nothing changes here. This is just a simplification of the code. Cc: Theodore Ts'o <tytso@mit.edu> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-21random: use computational hash for entropy extractionJason A. Donenfeld1-249/+55
The current 4096-bit LFSR used for entropy collection had a few desirable attributes for the context in which it was created. For example, the state was huge, which meant that /dev/random would be able to output quite a bit of accumulated entropy before blocking. It was also, in its time, quite fast at accumulating entropy byte-by-byte, which matters given the varying contexts in which mix_pool_bytes() is called. And its diffusion was relatively high, which meant that changes would ripple across several words of state rather quickly. However, it also suffers from a few security vulnerabilities. In particular, inputs learned by an attacker can be undone, but moreover, if the state of the pool leaks, its contents can be controlled and entirely zeroed out. I've demonstrated this attack with this SMT2 script, <https://xn--4db.cc/5o9xO8pb>, which Boolector/CaDiCal solves in a matter of seconds on a single core of my laptop, resulting in little proof of concept C demonstrators such as <https://xn--4db.cc/jCkvvIaH/c>. For basically all recent formal models of RNGs, these attacks represent a significant cryptographic flaw. But how does this manifest practically? If an attacker has access to the system to such a degree that he can learn the internal state of the RNG, arguably there are other lower hanging vulnerabilities -- side-channel, infoleak, or otherwise -- that might have higher priority. On the other hand, seed files are frequently used on systems that have a hard time generating much entropy on their own, and these seed files, being files, often leak or are duplicated and distributed accidentally, or are even seeded over the Internet intentionally, where their contents might be recorded or tampered with. Seen this way, an otherwise quasi-implausible vulnerability is a bit more practical than initially thought. Another aspect of the current mix_pool_bytes() function is that, while its performance was arguably competitive for the time in which it was created, it's no longer considered so. This patch improves performance significantly: on a high-end CPU, an i7-11850H, it improves performance of mix_pool_bytes() by 225%, and on a low-end CPU, a Cortex-A7, it improves performance by 103%. This commit replaces the LFSR of mix_pool_bytes() with a straight- forward cryptographic hash function, BLAKE2s, which is already in use for pool extraction. Universal hashing with a secret seed was considered too, something along the lines of <https://eprint.iacr.org/2013/338>, but the requirement for a secret seed makes for a chicken & egg problem. Instead we go with a formally proven scheme using a computational hash function, described in sections 5.1, 6.4, and B.1.8 of <https://eprint.iacr.org/2019/198>. BLAKE2s outputs 256 bits, which should give us an appropriate amount of min-entropy accumulation, and a wide enough margin of collision resistance against active attacks. mix_pool_bytes() becomes a simple call to blake2s_update(), for accumulation, while the extraction step becomes a blake2s_final() to generate a seed, with which we can then do a HKDF-like or BLAKE2X-like expansion, the first part of which we fold back as an init key for subsequent blake2s_update()s, and the rest we produce to the caller. This then is provided to our CRNG like usual. In that expansion step, we make opportunistic use of 32 bytes of RDRAND output, just as before. We also always reseed the crng with 32 bytes, unconditionally, or not at all, rather than sometimes with 16 as before, as we don't win anything by limiting beyond the 16 byte threshold. Going for a hash function as an entropy collector is a conservative, proven approach. The result of all this is a much simpler and much less bespoke construction than what's there now, which not only plugs a vulnerability but also improves performance considerably. Cc: Theodore Ts'o <tytso@mit.edu> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Reviewed-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-18hwrng: core - introduce rng_quality sysfs attributeDominik Brodowski1-1/+63
The rng_quality sysfs attribute returns the quality setting for the currently active hw_random device, in entropy bits per 1024 bits of input. Storing a value between 0 and 1024 to this file updates this estimate accordingly. Based on the updates to the quality setting, the rngd kernel thread may be stopped (if no hw_random device is trusted to return entropy), may be started (if the quality setting is increased from zero), or may use a different hw_random source (if that has higher quality output). Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-18hwrng: core - use per-rng quality value instead of global settingDominik Brodowski1-13/+20
The current_quality variable exposed as a module parameter is fundamentally broken: If it is set at boot time, it is overwritten once the first hw rng device is loaded; if it is set at runtime, it is without effect if the hw rng device had its quality value set to 0 (and no default_quality was set); and if a new rng is selected, it gets overwritten. Therefore, mark it as obsolete, and replace it by the per-rng quality setting. Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-18hwrng: core - start and stop in-kernel rngd in separate functionDominik Brodowski1-10/+14
Extract the start/stop logic for the in-kernel rngd thread to a separate function. Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-18hwrng: core - do not bother to order list of devices by qualityDominik Brodowski1-20/+16
There is no real reason why this list needs to be kept ordered by the driver-provided quality value -- a value which is set only by a handful of hw_random devices anyway. Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-16hwrng: optee-rng: use tee_shm_alloc_kernel_buf()Jens Wiklander1-3/+3
Uses the new simplified tee_shm_alloc_kernel_buf() function instead of the old deprecated tee_shm_alloc() function which required specific TEE_SHM-flags. Reviewed-by: Sumit Garg <sumit.garg@linaro.org> Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
2022-02-14Merge 5.17-rc4 into char-misc-nextGreg Kroah-Hartman1-17/+22
We need the char/misc fixes in here as well. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-14Backmerge tag 'v5.17-rc4' of ↵Dave Airlie1-17/+22
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into drm-next Daniel asked for this for some intel deps, so let's do it now. Signed-off-by: Dave Airlie <airlied@redhat.com>
2022-02-09spi: make remove callback a void functionUwe Kleine-König2-5/+2
The value returned by an spi driver's remove function is mostly ignored. (Only an error message is printed if the value is non-zero that the error is ignored.) So change the prototype of the remove function to return no value. This way driver authors are not tempted to assume that passing an error to the upper layer is a good idea. All drivers are adapted accordingly. There is no intended change of behaviour, all callbacks were prepared to return 0 before. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Marc Kleine-Budde <mkl@pengutronix.de> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com> Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Acked-by: Claudius Heine <ch@denx.de> Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com> Acked-by: Łukasz Stelmach <l.stelmach@samsung.com> Acked-by: Lee Jones <lee.jones@linaro.org> Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de Signed-off-by: Mark Brown <broonie@kernel.org>
2022-02-09tpm: st33zp24: Make st33zp24_remove() a void functionUwe Kleine-König4-11/+4
Up to now st33zp24_remove() returns zero unconditionally. Make it return no value instead which makes it easier to see in the callers that there is no error to handle. Also the return value of i2c and spi remove callbacks is ignored anyway. Link: https://lore.kernel.org/r/20220104231103.227924-1-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Lee Jones <lee.jones@linaro.org> Link: https://lore.kernel.org/r/20220123175201.34839-4-u.kleine-koenig@pengutronix.de Signed-off-by: Mark Brown <broonie@kernel.org>
2022-02-05hwrng: core - credit entropy for low quality sources of randomnessDominik Brodowski1-1/+10
In case the entropy quality is low, there may be less than one bit to credit in the call to add_hwgenerator_randomness(): The number of bytes returned by rng_get_data() multiplied by the current quality (in entropy bits per 1024 bits of input) must be larger than 128 to credit at least one bit. However, imx-rngc.c sets the quality to 19, but may return less than 32 bytes; hid_u2fzero.c sets the quality to 1; and users may override the quality setting manually. In case there is less than one bit to credit, keep track of it and add that credit to the next iteration. Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-05hwrng: core - break out of hwrng_fillfn if current rng is not trustedDominik Brodowski1-0/+3
For two reasons, current_quality may become zero within the rngd kernel thread: (1) The user lowers current_quality to 0 by writing to the sysfs module parameter file (note that increasing the quality from zero is without effect at the moment), or (2) there are two or more hwrng devices registered, and those which provide quality>0 are unregistered, but one with quality==0 remains. If current_quality is 0, the randomness is not trusted and cannot help to increase the entropy count. That will lead to continuous calls to the hwrngd thread and continuous stirring of the input pool with untrusted bits. Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-05hwrng: core - only set cur_rng_set_by_user if it is workingDominik Brodowski1-1/+2
In case the user-specified rng device is not working, it is not used; therefore cur_rng_set_by_user must not be set to 1. Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-05hwrng: core - use rng_fillbuf in add_early_randomness()Dominik Brodowski1-2/+2
Using rng_buffer in add_early_randomness() may race with rng_dev_read(). Use rng_fillbuf instead, as it is otherwise only used within the kernel by hwrng_fillfn() and therefore never exposed to userspace. Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-05hwrng: core - read() callback must be called for size of 32 or more bytesDominik Brodowski1-2/+1
According to <linux/hw_random.h>, the @max parameter of the ->read callback "is a multiple of 4 and >= 32 bytes". That promise was not kept by add_early_randomness(), which only asked for 16 bytes. As rng_buffer_size() is at least 32, we can simply ask for 32 bytes. Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-05hwrng: core - explicit ordering of initcallsDominik Brodowski1-1/+1
hw-random device drivers depend on the hw-random core being initialized. Make this ordering explicit, also for the case these drivers are built-in. As the core itself depends on misc_register() which is set up at subsys_initcall time, advance the initialization of the core (only) to the fs_initcall() level. Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-02-04random: only call crng_finalize_init() for primary_crngDominik Brodowski1-5/+5
crng_finalize_init() returns instantly if it is called for another pool than primary_crng. The test whether crng_finalize_init() is still required can be moved to the relevant caller in crng_reseed(), and crng_need_final_init can be reset to false if crng_finalize_init() is called with workqueues ready. Then, no previous callsite will call crng_finalize_init() unless it is needed, and we can get rid of the superfluous function parameter. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-04random: access primary_pool directly rather than through pointerDominik Brodowski1-7/+7
Both crng_initialize_primary() and crng_init_try_arch_early() are only called for the primary_pool. Accessing it directly instead of through a function parameter simplifies the code. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-04random: wake up /dev/random writers after zapJason A. Donenfeld1-1/+4
When account() is called, and the amount of entropy dips below random_write_wakeup_bits, we wake up the random writers, so that they can write some more in. However, the RNDZAPENTCNT/RNDCLEARPOOL ioctl sets the entropy count to zero -- a potential reduction just like account() -- but does not unblock writers. This commit adds the missing logic to that ioctl to unblock waiting writers. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-04random: continually use hwgenerator randomnessDominik Brodowski1-4/+6
The rngd kernel thread may sleep indefinitely if the entropy count is kept above random_write_wakeup_bits by other entropy sources. To make best use of multiple sources of randomness, mix entropy from hardware RNGs into the pool at least once within CRNG_RESEED_INTERVAL. Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-02-04hpet: remove unused writeq/readq function definitionsCorentin Labbe1-16/+1
On all arch using hpet, only i386 miss writeq/readq. Instead of rewriting them, use linux/io-64-nonatomic-lo-hi.h which already have them. Signed-off-by: Corentin Labbe <clabbe@baylibre.com> Link: https://lore.kernel.org/r/20220125140352.4085290-1-clabbe@baylibre.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-04hpet: fix style issue about braces and alignmentCorentin Labbe1-5/+6
This patch fix all style issue for braces and alignment Signed-off-by: Corentin Labbe <clabbe@baylibre.com> Link: https://lore.kernel.org/r/20220125140311.4084998-1-clabbe@baylibre.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-02-02block: remove genhd.hChristoph Hellwig1-1/+1
There is no good reason to keep genhd.h separate from the main blkdev.h header that includes it. So fold the contents of genhd.h into blkdev.h and remove genhd.h entirely. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20220124093913.742411-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-01Merge tag 'drm-misc-next-2022-01-27' of ↵Dave Airlie6-11/+14
git://anongit.freedesktop.org/drm/drm-misc into drm-next [airlied: add two missing Kconfig] drm-misc-next for v5.18: UAPI Changes: - Fix invalid IN_FORMATS blob when plane->format_mod_supported is NULL. Cross-subsystem Changes: - Assorted dt bindings updates. - Fix vga16fb vga checking on x86. - Fix extra semicolon in rwsem.h's _down_write_nest_lock. - Assorted small fixes to agp and fbdev drivers. - Fix oops in creating a udmabuf with 0 pages. - Hot-unplug firmware fb devices on forced removal - Reqquest memory region in simplefb and simpledrm, and don't make the ioresource as busy. Core Changes: - Mock a drm_plane in drm-plane-helper selftest. - Assorted bug fixes to device logging, dbi. - Use DP helper for sink count in mst. - Assorted documentation fixes. - Assorted small fixes. - Move DP headers to drm/dp, and add a drm dp helper module. - Move the buddy allocator from i915 to common drm. - Add simple pci and platform module init macros to remove a lot of boilerplate from some drivers. - Support microsoft extension for HMDs and specialized monitors. - Improve edid parser's deep color handling. - Add type 7 timing support to edid parser. - Add a weak backpointer to the ttm_bo from ttm_resource - Add 3 eDP panels. Driver Changes: - Add support for HDMI and JZ4780 to ingenic. - Add support for higher DP/eDP bitrates to nouveau. - Assorted driver fixes to tilcdc, vmwgfx, sn65dsi83, meson, stm, panfrost, v3d, gma500, vc4, virtio, mgag200, ast, radeon, amdgpu, nouveau, various bridge drivers. - Convert and revert exynos dsi support to bridge driver. - Add vcc supply regulator support for sn65dsi83. - More conversion of bridge/chipone-icn6211 to atomic. - Remove conflicting fb's from stm, and add support for new hw version. - Add device link in parade-ps8640 to fix suspend/resume. - Update Boe-tv110c9m init sequence. - Add wide screen support to AST2600. - Fix omapdrm implicit dma_buf fencing. - Add support for multiple overlay planes to vkms. - Convert bridge/anx7625 to atomic, add HDCP support, add eld support for audio, and fix HPD. - Add driver for ChromeOS privacy screen. - Handover display from firmware to vc4 more gracefully, and support nomodeset. - Add flexible and ycbcr pixel formats to stm/ltdc. - Convert exynos mipi dsi to atomic. - Add initial dual core group GPUs support to panfrost. - No longer add exclusive fence in amdgpu as shared fence. - Add CSC and full range supoprt to vc4. - Shutdown the display on system shutdown and unbind. - Add Multi-Inno Technology MI0700S4T-6 simple panel. Signed-off-by: Dave Airlie <airlied@redhat.com> From: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/456a23c6-7324-7543-0c45-751f30ef83f7@linux.intel.com
2022-01-31hwrng: cavium - HW_RANDOM_CAVIUM should depend on ARCH_THUNDERGeert Uytterhoeven1-1/+1
The Cavium ThunderX Random Number Generator is only present on Cavium ThunderX SoCs, and not available as an independent PCIe endpoint. Hence add a dependency on ARCH_THUNDER, to prevent asking the user about this driver when configuring a kernel without Cavium Thunder SoC support. Fixes: cc2f1908c6b8f625 ("hwrng: cavium - Add Cavium HWRNG driver for ThunderX SoC.") Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2022-01-22random: move the random sysctl declarations to its own fileXiaoming Ni1-2/+12
kernel/sysctl.c is a kitchen sink where everyone leaves their dirty dishes, this makes it very difficult to maintain. To help with this maintenance let's start by moving sysctls to places where they actually belong. The proc sysctl maintainers do not want to know what sysctl knobs you wish to add for your own piece of code, we just care about the core logic. So move the random sysctls to their own file and use register_sysctl_init(). [mcgrof@kernel.org: commit log update to justify the move] Link: https://lkml.kernel.org/r/20211124231435.1445213-3-mcgrof@kernel.org Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Antti Palosaari <crope@iki.fi> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Clemens Ladisch <clemens@ladisch.de> Cc: David Airlie <airlied@linux.ie> Cc: Douglas Gilbert <dgilbert@interlog.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Iurii Zaikin <yzaikin@google.com> Cc: James E.J. Bottomley <jejb@linux.ibm.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Joel Becker <jlbec@evilplan.org> Cc: John Ogness <john.ogness@linutronix.de> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Julia Lawall <julia.lawall@inria.fr> Cc: Kees Cook <keescook@chromium.org> Cc: Lukas Middendorf <kernel@tuxforce.de> Cc: Mark Fasheh <mark@fasheh.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Phillip Potter <phil@philpotter.co.uk> Cc: Qing Wang <wangqing@vivo.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Sebastian Reichel <sre@kernel.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Stephen Kitt <steve@sk2.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-22hpet: simplify subdirectory registration with register_sysctl()Luis Chamberlain1-21/+1
Patch series "sysctl: second set of kernel/sysctl cleanups", v2. This is the 2nd set of kernel/sysctl.c cleanups. The diff stat should reflect how this is a much better way to deal with theses. Fortunately coccinelle can be used to ensure correctness for most of these and/or future merge conflicts. Note that since this is part of a larger effort to cleanup kernel/sysctl.c I think we have no other option but to go with merging these patches in either Andrew's tree or keep them staged in a separate tree and send a merge request later. Otherwise kernel/sysctl.c will end up becoming a sore spot for the next merge window. This patch (of 8): There is no need to user boiler plate code to specify a set of base directories we're going to stuff sysctls under. Simplify this by using register_sysctl() and specifying the directory path directly. // pycocci sysctl-subdir-register-sysctl-simplify.cocci drivers/char/hpet.c @c1@ expression E1; identifier subdir, sysctls; @@ static struct ctl_table subdir[] = { { .procname = E1, .maxlen = 0, .mode = 0555, .child = sysctls, }, { } }; @c2@ identifier c1.subdir; expression E2; identifier base; @@ static struct ctl_table base[] = { { .procname = E2, .maxlen = 0, .mode = 0555, .child = subdir, }, { } }; @c3@ identifier c2.base; identifier header; @@ header = register_sysctl_table(base); @r1 depends on c1 && c2 && c3@ expression c1.E1; identifier c1.subdir, c1.sysctls; @@ -static struct ctl_table subdir[] = { - { - .procname = E1, - .maxlen = 0, - .mode = 0555, - .child = sysctls, - }, - { } -}; @r2 depends on c1 && c2 && c3@ identifier c1.subdir; expression c2.E2; identifier c2.base; @@ -static struct ctl_table base[] = { - { - .procname = E2, - .maxlen = 0, - .mode = 0555, - .child = subdir, - }, - { } -}; @initialize:python@ @@ def make_my_fresh_expression(s1, s2): return '"' + s1.strip('"') + "/" + s2.strip('"') + '"' @r3 depends on c1 && c2 && c3@ expression c1.E1; identifier c1.sysctls; expression c2.E2; identifier c2.base; identifier c3.header; fresh identifier E3 = script:python(E2, E1) { make_my_fresh_expression(E2, E1) }; @@ header = -register_sysctl_table(base); +register_sysctl(E3, sysctls); Generated-by: Coccinelle SmPL Link: https://lkml.kernel.org/r/20211123202422.819032-1-mcgrof@kernel.org Link: https://lkml.kernel.org/r/20211123202422.819032-2-mcgrof@kernel.org Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Iurii Zaikin <yzaikin@google.com> Cc: Xiaoming Ni <nixiaoming@huawei.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Clemens Ladisch <clemens@ladisch.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: David Airlie <airlied@linux.ie> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Mark Fasheh <mark@fasheh.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Jan Kara <jack@suse.cz> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Phillip Potter <phil@philpotter.co.uk> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Julia Lawall <julia.lawall@inria.fr> Cc: Lukas Middendorf <kernel@tuxforce.de> Cc: Antti Palosaari <crope@iki.fi> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Qing Wang <wangqing@vivo.com> Cc: Sebastian Reichel <sre@kernel.org> Cc: Sergey Senozhatsky <senozhatsky@chromium.org> Cc: Stephen Kitt <steve@sk2.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Douglas Gilbert <dgilbert@interlog.com> Cc: James E.J. Bottomley <jejb@linux.ibm.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: John Ogness <john.ogness@linutronix.de> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-01-18random: simplify arithmetic function flow in account()Jason A. Donenfeld1-11/+6
Now that have_bytes is never modified, we can simplify this function. First, we move the check for negative entropy_count to be first. That ensures that subsequent reads of this will be non-negative. Then, have_bytes and ibytes can be folded into their one use site in the min_t() function. Suggested-by: Dominik Brodowski <linux@dominikbrodowski.net> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: selectively clang-format where it makes senseJason A. Donenfeld1-110/+99
This is an old driver that has seen a lot of different eras of kernel coding style. In an effort to make it easier to code for, unify the coding style around the current norm, by accepting some of -- but certainly not all of -- the suggestions from clang-format. This should remove ambiguity in coding style, especially with regards to spacing, when code is being changed or amended. Consequently it also makes code review easier on the eyes, following one uniform style rather than several. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: access input_pool_data directly rather than through pointerJason A. Donenfeld1-13/+8
This gets rid of another abstraction we no longer need. It would be nice if we could instead make pool an array rather than a pointer, but the latent entropy plugin won't be able to do its magic in that case. So instead we put all accesses to the input pool's actual data through the input_pool_data array directly. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: cleanup fractional entropy shift constantsJason A. Donenfeld1-15/+13
The entropy estimator is calculated in terms of 1/8 bits, which means there are various constants where things are shifted by 3. Move these into our pool info enum with the other relevant constants. While we're at it, move an English assertion about sizes into a proper BUILD_BUG_ON so that the compiler can ensure this invariant. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: prepend remaining pool constants with POOL_Jason A. Donenfeld1-20/+20
The other pool constants are prepended with POOL_, but not these last ones. Rename them. This will then let us move them into the enum in the following commit. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: de-duplicate INPUT_POOL constantsJason A. Donenfeld1-11/+6
We already had the POOL_* constants, so deduplicate the older INPUT_POOL ones. As well, fold EXTRACT_SIZE into the poolinfo enum, since it's related. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: remove unused OUTPUT_POOL constantsJason A. Donenfeld1-3/+1
We no longer have an output pool. Rather, we have just a wakeup bits threshold for /dev/random reads, presumably so that processes don't hang. This value, random_write_wakeup_bits, is configurable anyway. So all the no longer usefully named OUTPUT_POOL constants were doing was setting a reasonable default for random_write_wakeup_bits. This commit gets rid of the constants and just puts it all in the default value of random_write_wakeup_bits. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: rather than entropy_store abstraction, use globalJason A. Donenfeld1-123/+96
Originally, the RNG used several pools, so having things abstracted out over a generic entropy_store object made sense. These days, there's only one input pool, and then an uneven mix of usage via the abstraction and usage via &input_pool. Rather than this uneasy mixture, just get rid of the abstraction entirely and have things always use the global. This simplifies the code and makes reading it a bit easier. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: remove unused extract_entropy() reserved argumentJason A. Donenfeld1-10/+7
This argument is always set to zero, as a result of us not caring about keeping a certain amount reserved in the pool these days. So just remove it and cleanup the function signatures. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: remove incomplete last_data logicJason A. Donenfeld1-35/+4
There were a few things added under the "if (fips_enabled)" banner, which never really got completed, and the FIPS people anyway are choosing a different direction. Rather than keep around this halfbaked code, get rid of it so that we can focus on a single design of the RNG rather than two designs. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: cleanup integer typesJason A. Donenfeld1-53/+52
Rather than using the userspace type, __uXX, switch to using uXX. And rather than using variously chosen `char *` or `unsigned char *`, use `u8 *` uniformly for things that aren't strings, in the case where we are doing byte-by-byte traversal. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: cleanup poolinfo abstractionJason A. Donenfeld1-37/+30
Now that we're only using one polynomial, we can cleanup its representation into constants, instead of passing around pointers dynamically to select different polynomials. This improves the codegen and makes the code a bit more straightforward. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18random: fix typo in commentsSchspa Shi1-1/+1
s/or/for Signed-off-by: Schspa Shi <schspa@gmail.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-01-18Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds2-3/+3
Pull virtio updates from Michael Tsirkin: "virtio,vdpa,qemu_fw_cfg: features, cleanups, and fixes. - partial support for < MAX_ORDER - 1 granularity for virtio-mem - driver_override for vdpa - sysfs ABI documentation for vdpa - multiqueue config support for mlx5 vdpa - and misc fixes, cleanups" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: (42 commits) vdpa/mlx5: Fix tracking of current number of VQs vdpa/mlx5: Fix is_index_valid() to refer to features vdpa: Protect vdpa reset with cf_mutex vdpa: Avoid taking cf_mutex lock on get status vdpa/vdpa_sim_net: Report max device capabilities vdpa: Use BIT_ULL for bit operations vdpa/vdpa_sim: Configure max supported virtqueues vdpa/mlx5: Report max device capabilities vdpa: Support reporting max device capabilities vdpa/mlx5: Restore cur_num_vqs in case of failure in change_num_qps() vdpa: Add support for returning device configuration information vdpa/mlx5: Support configuring max data virtqueue vdpa/mlx5: Fix config_attr_mask assignment vdpa: Allow to configure max data virtqueues vdpa: Read device configuration only if FEATURES_OK vdpa: Sync calls set/get config/status with cf_mutex vdpa/mlx5: Distribute RX virtqueues in RQT object vdpa: Provide interface to read driver features vdpa: clean up get_config_size ret value handling virtio_ring: mark ring unused on error ...