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path: root/drivers/char/hw_random/core.c
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2018-10-05hwrng: core - document the quality fieldMichael S. Tsirkin
quality field is currently documented as being 'per mill'. In fact the math involved is: add_hwgenerator_randomness((void *)rng_fillbuf, rc, rc * current_quality * 8 >> 10); thus the actual definition is "bits of entropy per 1024 bits of input". The current documentation seems to have confused multiple people in the past, let's fix the documentation to match code. An alternative is to change core to match driver expectations, replacing rc * current_quality * 8 >> 10 with rc * current_quality / 1000 but that has performance costs, so probably isn't a good option. Fixes: 0f734e6e768 ("hwrng: add per-device entropy derating") Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-06-15hwrng: core - Always drop the RNG in hwrng_unregister()Michael Büsch
enable_best_rng() is used in hwrng_unregister() to switch away from the currently active RNG, if that is the one currently being removed. However enable_best_rng() might fail, if the next RNG's init routine fails. In that case enable_best_rng() will return an error code and the currently active RNG will remain active. After unregistering this might lead to crashes due to use-after-free. Fix this by dropping the currently active RNG, if enable_best_rng() failed. This will result in no RNG to be active, if the next-best one failed to initialize. This problem was introduced by 142a27f0a731ddcf467546960a5585970ca98e21 Fixes: 142a27f0a731 ("hwrng: core - Reset user selected rng by...") Reported-by: Wirz <spam@lukas-wirz.de> Tested-by: Wirz <spam@lukas-wirz.de> Signed-off-by: Michael Büsch <m@bues.ch> Cc: stable@vger.kernel.org Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-12-22hwrng: core - Clean up RNG list when last hwrng is unregisteredGary R Hook
Commit 142a27f0a731 added support for a "best" RNG, and in doing so introduced a hang from rmmod/modprobe -r when the last RNG on the list was unloaded. When the hwrng list is depleted, return the global variables to their original state and decrement all references to the object. Fixes: 142a27f0a731 ("hwrng: core - Reset user selected rng by writing "" to rng_current") Signed-off-by: Gary R Hook <gary.hook@amd.com> Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-03hwrng: core - Reset user selected rng by writing "" to rng_currentPrasannaKumar Muralidharan
User is able to select a chosen rng by writing its name to rng_current but there is no way to reset it without unbinding the rng. Let user write "" to rng_current and delesect the chosen rng. Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> reviewed-by: Harald Freudenberger <freude@linux.vnet.ibm.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-10-12hwrng: core - pr_err() strings should end with newlinesArvind Yadav
pr_err() messages should terminated with a new-line to avoid other messages being concatenated onto the end. Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-07-18hwrng: remember rng chosen by userHarald Freudenberger
When a user chooses a rng source via sysfs attribute this rng should be sticky, even when other sources with better quality to register. This patch introduces a simple way to remember the user's choice. This is reflected by a new sysfs attribute file 'rng_selected' which shows if the current rng has been chosen by userspace. The new attribute file shows '1' for user selected rng and '0' otherwise. Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com> Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-07-18hwrng: use rng source with best qualityHarald Freudenberger
This patch rewoks the hwrng to always use the rng source with best entropy quality. On registation and unregistration the hwrng now tries to choose the best (= highest quality value) rng source. The handling of the internal list of registered rng sources is now always sorted by quality and the top most rng chosen. Signed-off-by: Harald Freudenberger <freude@linux.vnet.ibm.com> Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-03-02sched/headers: Prepare to move signal wakeup & sigpending methods from ↵Ingo Molnar
<linux/sched.h> into <linux/sched/signal.h> Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-23Merge branch 'linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto update from Herbert Xu: "API: - Try to catch hash output overrun in testmgr - Introduce walksize attribute for batched walking - Make crypto_xor() and crypto_inc() alignment agnostic Algorithms: - Add time-invariant AES algorithm - Add standalone CBCMAC algorithm Drivers: - Add NEON acclerated chacha20 on ARM/ARM64 - Expose AES-CTR as synchronous skcipher on ARM64 - Add scalar AES implementation on ARM64 - Improve scalar AES implementation on ARM - Improve NEON AES implementation on ARM/ARM64 - Merge CRC32 and PMULL instruction based drivers on ARM64 - Add NEON acclerated CBCMAC/CMAC/XCBC AES on ARM64 - Add IPsec AUTHENC implementation in atmel - Add Support for Octeon-tx CPT Engine - Add Broadcom SPU driver - Add MediaTek driver" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (142 commits) crypto: xts - Add ECB dependency crypto: cavium - switch to pci_alloc_irq_vectors crypto: cavium - switch to pci_alloc_irq_vectors crypto: cavium - remove dead MSI-X related define crypto: brcm - Avoid double free in ahash_finup() crypto: cavium - fix Kconfig dependencies crypto: cavium - cpt_bind_vq_to_grp could return an error code crypto: doc - fix typo hwrng: omap - update Kconfig help description crypto: ccm - drop unnecessary minimum 32-bit alignment crypto: ccm - honour alignmask of subordinate MAC cipher crypto: caam - fix state buffer DMA (un)mapping crypto: caam - abstract ahash request double buffering crypto: caam - fix error path for ctx_dma mapping failure crypto: caam - fix DMA API leaks for multiple setkey() calls crypto: caam - don't dma_map key for hash algorithms crypto: caam - use dma_map_sg() return code crypto: caam - replace sg_count() with sg_nents_for_len() crypto: caam - check sg_count() return value crypto: caam - fix HW S/G in ablkcipher_giv_edesc_alloc() ..
2017-02-08Revert "hwrng: core - zeroize buffers with random data"David Daney
This reverts commit 2cc751545854d7bd7eedf4d7e377bb52e176cd07. With this commit in place I get on a Cavium ThunderX (arm64) system: $ if=/dev/hwrng bs=256 count=1 | od -t x1 -A x -v > rng-bad.txt 1+0 records in 1+0 records out 256 bytes (256 B) copied, 9.1171e-05 s, 2.8 MB/s $ dd if=/dev/hwrng bs=256 count=1 | od -t x1 -A x -v >> rng-bad.txt 1+0 records in 1+0 records out 256 bytes (256 B) copied, 9.6141e-05 s, 2.7 MB/s $ cat rng-bad.txt 000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000050 00 00 00 00 37 20 46 ae d0 fc 1c 55 25 6e b0 b8 000060 7c 7e d7 d4 00 0f 6f b2 91 1e 30 a8 fa 3e 52 0e 000070 06 2d 53 30 be a1 20 0f aa 56 6e 0e 44 6e f4 35 000080 b7 6a fe d2 52 70 7e 58 56 02 41 ea d1 9c 6a 6a 000090 d1 bd d8 4c da 35 45 ef 89 55 fc 59 d5 cd 57 ba 0000a0 4e 3e 02 1c 12 76 43 37 23 e1 9f 7a 9f 9e 99 24 0000b0 47 b2 de e3 79 85 f6 55 7e ad 76 13 4f a0 b5 41 0000c0 c6 92 42 01 d9 12 de 8f b4 7b 6e ae d7 24 fc 65 0000d0 4d af 0a aa 36 d9 17 8d 0e 8b 7a 3b b6 5f 96 47 0000e0 46 f7 d8 ce 0b e8 3e c6 13 a6 2c b6 d6 cc 17 26 0000f0 e3 c3 17 8e 9e 45 56 1e 41 ef 29 1a a8 65 c8 3a 000100 000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000020 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000030 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000040 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 000050 00 00 00 00 f4 90 65 aa 8b f2 5e 31 01 53 b4 d4 000060 06 c0 23 a2 99 3d 01 e4 b0 c1 b1 55 0f 80 63 cf 000070 33 24 d8 3a 1d 5e cd 2c ba c0 d0 18 6f bc 97 46 000080 1e 19 51 b1 90 15 af 80 5e d1 08 0d eb b0 6c ab 000090 6a b4 fe 62 37 c5 e1 ee 93 c3 58 78 91 2a d5 23 0000a0 63 50 eb 1f 3b 84 35 18 cf b2 a4 b8 46 69 9e cf 0000b0 0c 95 af 03 51 45 a8 42 f1 64 c9 55 fc 69 76 63 0000c0 98 9d 82 fa 76 85 24 da 80 07 29 fe 4e 76 0c 61 0000d0 ff 23 94 4f c8 5c ce 0b 50 e8 31 bc 9d ce f4 ca 0000e0 be ca 28 da e6 fa cc 64 1c ec a8 41 db fe 42 bd 0000f0 a0 e2 4b 32 b4 52 ba 03 70 8e c1 8e d0 50 3a c6 000100 To my untrained mental entropy detector, the first several bytes of each read from /dev/hwrng seem to not be very random (i.e. all zero). When I revert the patch (apply this patch), I get back to what we have in v4.9, which looks like (much more random appearing): $ dd if=/dev/hwrng bs=256 count=1 | od -t x1 -A x -v > rng-good.txt 1+0 records in 1+0 records out 256 bytes (256 B) copied, 0.000252233 s, 1.0 MB/s $ dd if=/dev/hwrng bs=256 count=1 | od -t x1 -A x -v >> rng-good.txt 1+0 records in 1+0 records out 256 bytes (256 B) copied, 0.000113571 s, 2.3 MB/s $ cat rng-good.txt 000000 75 d1 2d 19 68 1f d2 26 a1 49 22 61 66 e8 09 e5 000010 e0 4e 10 d0 1a 2c 45 5d 59 04 79 8e e2 b7 2c 2e 000020 e8 ad da 34 d5 56 51 3d 58 29 c7 7a 8e ed 22 67 000030 f9 25 b9 fb c6 b7 9c 35 1f 84 21 35 c1 1d 48 34 000040 45 7c f6 f1 57 63 1a 88 38 e8 81 f0 a9 63 ad 0e 000050 be 5d 3e 74 2e 4e cb 36 c2 01 a8 14 e1 38 e1 bb 000060 23 79 09 56 77 19 ff 98 e8 44 f3 27 eb 6e 0a cb 000070 c9 36 e3 2a 96 13 07 a0 90 3f 3b bd 1d 04 1d 67 000080 be 33 14 f8 02 c2 a4 02 ab 8b 5b 74 86 17 f0 5e 000090 a1 d7 aa ef a6 21 7b 93 d1 85 86 eb 4e 8c d0 4c 0000a0 56 ac e4 45 27 44 84 9f 71 db 36 b9 f7 47 d7 b3 0000b0 f2 9c 62 41 a3 46 2b 5b e3 80 63 a4 35 b5 3c f4 0000c0 bc 1e 3a ad e4 59 4a 98 6c e8 8d ff 1b 16 f8 52 0000d0 05 5c 2f 52 2a 0f 45 5b 51 fb 93 97 a4 49 4f 06 0000e0 f3 a0 d1 1e ba 3d ed a7 60 8f bb 84 2c 21 94 2d 0000f0 b3 66 a6 61 1e 58 30 24 85 f8 c8 18 c3 77 00 22 000100 000000 73 ca cc a1 d9 bb 21 8d c3 5c f3 ab 43 6d a7 a4 000010 4a fd c5 f4 9c ba 4a 0f b1 2e 19 15 4e 84 26 e0 000020 67 c9 f2 52 4d 65 1f 81 b7 8b 6d 2b 56 7b 99 75 000030 2e cd d0 db 08 0c 4b df f3 83 c6 83 00 2e 2b b8 000040 0f af 61 1d f2 02 35 74 b5 a4 6f 28 f3 a1 09 12 000050 f2 53 b5 d2 da 45 01 e5 12 d6 46 f8 0b db ed 51 000060 7b f4 0d 54 e0 63 ea 22 e2 1d d0 d6 d0 e7 7e e0 000070 93 91 fb 87 95 43 41 28 de 3d 8b a3 a8 8f c4 9e 000080 30 95 12 7a b2 27 28 ff 37 04 2e 09 7c dd 7c 12 000090 e1 50 60 fb 6d 5f a8 65 14 40 89 e3 4c d2 87 8f 0000a0 34 76 7e 66 7a 8e 6b a3 fc cf 38 52 2e f9 26 f0 0000b0 98 63 15 06 34 99 b2 88 4f aa d8 14 88 71 f1 81 0000c0 be 51 11 2b f4 7e a0 1e 12 b2 44 2e f6 8d 84 ea 0000d0 63 82 2b 66 b3 9a fd 08 73 5a c2 cc ab 5a af b1 0000e0 88 e3 a6 80 4b fc db ed 71 e0 ae c0 0a a4 8c 35 0000f0 eb 89 f9 8a 4b 52 59 6f 09 7c 01 3f 56 e7 c7 bf 000100 Signed-off-by: David Daney <david.daney@cavium.com> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-27hwrng: core - remove unused PFX macroCorentin LABBE
This patch remove the unused PFX macro. Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-27hwrng: core - Move hwrng miscdev minor number to include/linux/miscdevice.hCorentin LABBE
This patch move the define for hwrng's miscdev minor number to include/linux/miscdevice.h. It's better that all minor number are in the same place. Rename it to HWRNG_MINOR (from RNG_MISCDEV_MINOR) in he process since no other miscdev define have MISCDEV in their name. Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-27hwrng: core - Replace asm/uaccess.h by linux/uaccess.hCorentin LABBE
This patch fix the checkpatch warning about asm/uaccess.h. In the same time, we sort the headers in alphabetical order. Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-27hwrng: core - Rewrite the headerCorentin LABBE
checkpatch have lot of complaint about header. Furthermore, the header have some offtopic/useless information. This patch rewrite a proper header. Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-27hwrng: core - rewrite better comparison to NULLCorentin LABBE
This patch fix the checkpatch warning "Comparison to NULL could be written "!ptr" Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-27hwrng: core - do not use multiple blank linesCorentin LABBE
This patch fix the checkpatch warning "Please don't use multiple blank lines" Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-24Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds
This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-01hwrng: core - zeroize buffers with random dataStephan Mueller
The HWRNG core allocates two buffers during initialization which are used to obtain random data. After that data is processed, it is now zeroized as it is possible that the HWRNG core will not be asked to produce more random data for a long time. This prevents leaving such sensitive data in memory. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-10-19hwrng: core - Don't use a stack buffer in add_early_randomness()Andrew Lutomirski
hw_random carefully avoids using a stack buffer except in add_early_randomness(). This causes a crash in virtio_rng if CONFIG_VMAP_STACK=y. Reported-by: Matt Mullins <mmullins@mmlx.us> Tested-by: Matt Mullins <mmullins@mmlx.us> Fixes: d3cc7996473a ("hwrng: fetch randomness only after device init") Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-09-13hwrng: core - Allocate memory during module initPrasannaKumar Muralidharan
In core rng_buffer and rng_fillbuf is allocated in hwrng_register only once and it is freed during module exit. This patch moves allocating rng_buffer and rng_fillbuf from hwrng_register to rng core's init. This avoids checking whether rng_buffer and rng_fillbuf was allocated from every hwrng_register call. Also moving them to module init makes it explicit that it is freed in module exit. Change in v2: Fix memory leak when register_miscdev fails. Signed-off-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-12-04hwrng: core - sleep interruptible in readJiri Slaby
hwrng kthread can be waiting via hwrng_fillfn for some data from a rng like virtio-rng: hwrng D ffff880093e17798 0 382 2 0x00000000 ... Call Trace: [<ffffffff817339c6>] wait_for_completion_killable+0x96/0x210 [<ffffffffa00aa1b7>] virtio_read+0x57/0xf0 [virtio_rng] [<ffffffff814f4a35>] hwrng_fillfn+0x75/0x130 [<ffffffff810aa243>] kthread+0xf3/0x110 And when some user program tries to read the /dev node in this state, we get: rngd D ffff880093e17798 0 762 1 0x00000004 ... Call Trace: [<ffffffff817351ac>] mutex_lock_nested+0x15c/0x3e0 [<ffffffff814f478e>] rng_dev_read+0x6e/0x240 [<ffffffff81231958>] __vfs_read+0x28/0xe0 [<ffffffff81232393>] vfs_read+0x83/0x130 And this is indeed unkillable. So use mutex_lock_interruptible instead of mutex_lock in rng_dev_read and exit immediatelly when interrupted. And possibly return already read data, if any (as POSIX allows). v2: use ERESTARTSYS instead of EINTR Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Matt Mackall <mpm@selenic.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: <linux-crypto@vger.kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-09-21hwrng: core - Simplify RNG switching from sysfsLee Jones
If we attempt to use sysfs to change the current RNG in the usual way i.e. issuing something like: `echo 8a8a000.rng > /sys/devices/virtual/misc/hw_random/rng_current` ... it will fail because the code doesn't currently take the '\n' into consideration. Well, now it does. Signed-off-by: Lee Jones <lee.jones@linaro.org> Acked-by: Peter Korsgaard <peter@korsgaard.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-07-28hwrng: core - correct error check of kthread_run callMartin Schwidefsky
The kthread_run() function can return two different error values but the hwrng core only checks for -ENOMEM. If the other error value -EINTR is returned it is assigned to hwrng_fill and later used on a kthread_stop() call which naturally crashes. Cc: stable@vger.kernel.org Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-04-21Merge tag 'char-misc-4.1-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc driver updates from Greg KH: "Here's the big char/misc driver patchset for 4.1-rc1. Lots of different driver subsystem updates here, nothing major, full details are in the shortlog. All of this has been in linux-next for a while" * tag 'char-misc-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (133 commits) mei: trace: remove unused TRACE_SYSTEM_STRING DTS: ARM: OMAP3-N900: Add lis3lv02d support Documentation: DT: lis302: update wakeup binding lis3lv02d: DT: add wakeup unit 2 and wakeup threshold lis3lv02d: DT: use s32 to support negative values Drivers: hv: hv_balloon: correctly handle num_pages>INT_MAX case Drivers: hv: hv_balloon: correctly handle val.freeram<num_pages case mei: replace check for connection instead of transitioning mei: use mei_cl_is_connected consistently mei: fix mei_poll operation hv_vmbus: Add gradually increased delay for retries in vmbus_post_msg() Drivers: hv: hv_balloon: survive ballooning request with num_pages=0 Drivers: hv: hv_balloon: eliminate jumps in piecewiese linear floor function Drivers: hv: hv_balloon: do not online pages in offline blocks hv: remove the per-channel workqueue hv: don't schedule new works in vmbus_onoffer()/vmbus_onoffer_rescind() hv: run non-blocking message handlers in the dispatch tasklet coresight: moving to new "hwtracing" directory coresight-tmc: Adding a status interface to sysfs coresight: remove the unnecessary configuration coresight-default-sink ...
2015-03-25hwrng: Avoid manual device_create_file() callsTakashi Iwai
Use the new group field of struct miscdevice for managing the sysfs entries instead of manually adding/removing via device_create_file() and device_remove_file(). This simplifies the code a lot and fixes the possible races. Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-18hwrng: core - allow perfect entropy from hardware devicesKeith Packard
Hardware random number quality is measured from 0 (no entropy) to 1024 (perfect entropy). Allow hardware devices to assert the full range by truncating the device-provided value at 1024 instead of 1023. Signed-off-by: Keith Packard <keithp@keithp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-03-16hwrng: add devm_* interfacesDmitry Torokhov
This change adds devm_hwrng_register and devm_hwrng_unregister which use can simplify error unwinding and unbinding code paths in device drivers. Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-26hwrng: core - Move hwrng_init call into set_current_rngHerbert Xu
We always do hwrng_init in set_current_rng. In fact, our current reference count system relies on this. So make this explicit by moving hwrng_init into set_current_rng. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-26hwrng: core - Drop current rng in set_current_rngHerbert Xu
Rather than having callers of set_current_rng call drop_current_rng, we can do it directly in set_current_rng. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-26hwrng: core - Do not register device opportunisticallyHerbert Xu
Currently we only register the device when a valid RNG is added. However the way it's done is buggy because we test whether there is a current RNG to determine whether we need to register. As the current RNG may be missing due to a reinitialisation error this can lead to a reregistration of the device. As the device already has to handle a NULL current RNG anyway, let's just register the device always and remove the complexity. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-26hwrng: core - Fix current_rng init/cleanup race yet againHerbert Xu
The kref solution is still buggy because we were only focusing on the register/unregister race. The same race affects the setting of current_rng through sysfs. This patch fixes it by using kref_get_unless_zero. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-26hwrng: core - Use struct completion for cleanup_doneHerbert Xu
There is no point in doing a manual completion for cleanup_done when struct completion fits in perfectly. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-22hwrng: don't init list element we're about to add to list.Rusty Russell
Another interesting anti-pattern. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-22hwrng: don't double-check old_rng.Rusty Russell
Interesting anti-pattern. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-22hwrng: fix unregister race.Rusty Russell
The previous patch added one potential problem: we can still be reading from a hwrng when it's unregistered. Add a wait for zero in the hwrng_unregister path. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Amos Kong <akong@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-22hwrng: use reference counts on each struct hwrng.Rusty Russell
current_rng holds one reference, and we bump it every time we want to do a read from it. This means we only hold the rng_mutex to grab or drop a reference, so accessing /sys/devices/virtual/misc/hw_random/rng_current doesn't block on read of /dev/hwrng. Using a kref is overkill (we're always under the rng_mutex), but a standard pattern. This also solves the problem that the hwrng_fillfn thread was accessing current_rng without a lock, which could change (eg. to NULL) underneath it. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Amos Kong <akong@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-22hwrng: move some code out mutex_lock for avoiding underlying deadlockAmos Kong
In next patch, we use reference counting for each struct hwrng, changing reference count also needs to take mutex_lock. Before releasing the lock, if we try to stop a kthread that waits to take the lock to reduce the referencing count, deadlock will occur. Signed-off-by: Amos Kong <akong@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-12-22hwrng: place mutex around read functions and buffers.Rusty Russell
There's currently a big lock around everything, and it means that we can't query sysfs (eg /sys/devices/virtual/misc/hw_random/rng_current) while the rng is reading. This is a real problem when the rng is slow, or blocked (eg. virtio_rng with qemu's default /dev/random backend) This doesn't help (it leaves the current lock untouched), just adds a lock to protect the read function and the static buffers, in preparation for transition. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-10-24hwrng: core - Changed from using strncat to strlcatRickard Strandqvist
The buf is used to hold the list of hwrng devices registered. The old code ensures we don't walk off the end of buf as we fill it, but it's unnecessarily complicated and thus difficult to maintain. Simplify it by using strlcat. Signed-off-by: Rickard Strandqvist <rickard_strandqvist@spectrumdigital.se> Reviewed-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-08-10Merge tag 'virtio-next-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux Pull virtio updates from Rusty Russell. * tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: Revert "hwrng: virtio - ensure reads happen after successful probe" virtio: rng: delay hwrng_register() till driver is ready virtio: rng: re-arrange struct elements for better packing virtio: rng: remove unused struct element virtio: Replace DEFINE_PCI_DEVICE_TABLE macro use virtio: console: remove unnecessary null test before debugfs_remove_recursive
2014-08-06Merge tag 'random_for_linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random Pull randomness updates from Ted Ts'o: "Cleanups and bug fixes to /dev/random, add a new getrandom(2) system call, which is a superset of OpenBSD's getentropy(2) call, for use with userspace crypto libraries such as LibreSSL. Also add the ability to have a kernel thread to pull entropy from hardware rng devices into /dev/random" * tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random: hwrng: Pass entropy to add_hwgenerator_randomness() in bits, not bytes random: limit the contribution of the hw rng to at most half random: introduce getrandom(2) system call hw_random: fix sparse warning (NULL vs 0 for pointer) random: use registers from interrupted code for CPU's w/o a cycle counter hwrng: add per-device entropy derating hwrng: create filler thread random: add_hwgenerator_randomness() for feeding entropy from devices random: use an improved fast_mix() function random: clean up interrupt entropy accounting for archs w/o cycle counters random: only update the last_pulled time if we actually transferred entropy random: remove unneeded hash of a portion of the entropy pool random: always update the entropy pool under the spinlock
2014-08-05hwrng: Pass entropy to add_hwgenerator_randomness() in bits, not bytesStephen Boyd
rng_get_data() returns the number of bytes read from the hardware. The entropy argument to add_hwgenerator_randomness() is passed directly to credit_entropy_bits() so we should be passing the number of bits, not bytes here. Fixes: be4000bc464 "hwrng: create filler thread" Acked-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-07-27Revert "hwrng: virtio - ensure reads happen after successful probe"Amit Shah
This reverts commit e052dbf554610e2104c5a7518c4d8374bed701bb. Now that we use the virtio ->scan() function to register with the hwrng core, we will not get read requests till probe is successfully finished. So revert the workaround we had in place to refuse read requests while we were not yet setup completely. Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2014-07-15hw_random: fix sparse warning (NULL vs 0 for pointer)Torsten Duwe
Signed-off-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-07-15hwrng: add per-device entropy deratingTorsten Duwe
This patch introduces a derating factor to struct hwrng for the random bits going into the kernel input pool, and a common default derating for drivers which do not specify one. Signed-off-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Acked-by: H. Peter Anvin <hpa@zytor.com>
2014-07-15hwrng: create filler threadTorsten Duwe
This can be viewed as the in-kernel equivalent of hwrngd; like FUSE it is a good thing to have a mechanism in user land, but for some reasons (simplicity, secrecy, integrity, speed) it may be better to have it in kernel space. This patch creates a thread once a hwrng registers, and uses the previously established add_hwgenerator_randomness() to feed its data to the input pool as long as needed. A derating factor is used to bias the entropy estimation and to disable this mechanism entirely when set to zero. Signed-off-by: Torsten Duwe <duwe@suse.de> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Acked-by: H. Peter Anvin <hpa@zytor.com>
2014-07-14hwrng: virtio - ensure reads happen after successful probeAmit Shah
The hwrng core asks for random data in the hwrng_register() call itself from commit d9e7972619. This doesn't play well with virtio -- the DRIVER_OK bit is only set by virtio core on a successful probe, and we're not yet out of our probe routine when this call is made. This causes the host to not acknowledge any requests we put in the virtqueue, and the insmod or kernel boot process just waits for data to arrive from the host, which never happens. CC: Kees Cook <keescook@chromium.org> CC: Jason Cooper <jason@lakedaemon.net> CC: Herbert Xu <herbert@gondor.apana.org.au> CC: <stable@vger.kernel.org> # For v3.15+ Reviewed-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-07-14hwrng: fetch randomness only after device initAmit Shah
Commit d9e7972619334 "hwrng: add randomness to system from rng sources" added a call to rng_get_data() from the hwrng_register() function. However, some rng devices need initialization before data can be read from them. This commit makes the call to rng_get_data() depend on no init fn pointer being registered by the device. If an init function is registered, this call is made after device init. CC: Kees Cook <keescook@chromium.org> CC: Jason Cooper <jason@lakedaemon.net> CC: Herbert Xu <herbert@gondor.apana.org.au> CC: <stable@vger.kernel.org> # For v3.15+ Signed-off-by: Amit Shah <amit.shah@redhat.com> Reviewed-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-04-03Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6Linus Torvalds
Pull crypto updates from Herbert Xu: "Here is the crypto update for 3.15: - Added 3DES driver for OMAP4/AM43xx - Added AVX2 acceleration for SHA - Added hash-only AEAD algorithms in caam - Removed tegra driver as it is not functioning and the hardware is too slow - Allow blkcipher walks over AEAD (needed for ARM) - Fixed unprotected FPU/SSE access in ghash-clmulni-intel - Fixed highmem crash in omap-sham - Add (zero entropy) randomness when initialising hardware RNGs - Fixed unaligned ahash comletion functions - Added soft module depedency for crc32c for initrds that use crc32c" * git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (60 commits) crypto: ghash-clmulni-intel - use C implementation for setkey() crypto: x86/sha1 - reduce size of the AVX2 asm implementation crypto: x86/sha1 - fix stack alignment of AVX2 variant crypto: x86/sha1 - re-enable the AVX variant crypto: sha - SHA1 transform x86_64 AVX2 crypto: crypto_wq - Fix late crypto work queue initialization crypto: caam - add missing key_dma unmap crypto: caam - add support for aead null encryption crypto: testmgr - add aead null encryption test vectors crypto: export NULL algorithms defines crypto: caam - remove error propagation handling crypto: hash - Simplify the ahash_finup implementation crypto: hash - Pull out the functions to save/restore request crypto: hash - Fix the pointer voodoo in unaligned ahash crypto: caam - Fix first parameter to caam_init_rng crypto: omap-sham - Map SG pages if they are HIGHMEM before accessing crypto: caam - Dynamic memory allocation for caam_rng_ctx object crypto: allow blkcipher walks over AEAD data crypto: remove direct blkcipher_walk dependency on transform hwrng: add randomness to system from rng sources ...
2014-03-10hwrng: add randomness to system from rng sourcesKees Cook
When bringing a new RNG source online, it seems like it would make sense to use some of its bytes to make the system entropy pool more random, as done with all sorts of other devices that contain per-device or per-boot differences. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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