linux.git/drivers/char/hw_random/core.c, branch v3.19

hwrng: core - Changed from using strncat to strlcat

2014-10-24T14:52:27+00:00

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 
Reviewed-by: Jason Cooper 
Signed-off-by: Herbert Xu

Merge tag 'virtio-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2014-08-11T04:31:04+00:00

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

Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random

2014-08-06T15:16:24+00:00

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

hwrng: Pass entropy to add_hwgenerator_randomness() in bits, not bytes

2014-08-05T20:50:10+00:00

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 
Signed-off-by: Stephen Boyd 
Signed-off-by: Theodore Ts'o

Revert "hwrng: virtio - ensure reads happen after successful probe"

2014-07-27T11:37:20+00:00

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 
Signed-off-by: Rusty Russell

hw_random: fix sparse warning (NULL vs 0 for pointer)

2014-07-15T08:49:41+00:00

Signed-off-by: Torsten Duwe 
Signed-off-by: Theodore Ts'o

hwrng: add per-device entropy derating

2014-07-15T08:49:40+00:00

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 
Signed-off-by: Theodore Ts'o 
Acked-by: H. Peter Anvin

hwrng: create filler thread

2014-07-15T08:49:40+00:00

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 
Signed-off-by: Theodore Ts'o 
Acked-by: H. Peter Anvin

hwrng: virtio - ensure reads happen after successful probe

2014-07-14T12:48:17+00:00

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 
CC: Jason Cooper 
CC: Herbert Xu 
CC:  # For v3.15+
Reviewed-by: Jason Cooper 
Signed-off-by: Amit Shah 
Signed-off-by: Herbert Xu

hwrng: fetch randomness only after device init

2014-07-14T12:48:17+00:00

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 
CC: Jason Cooper 
CC: Herbert Xu 
CC:  # For v3.15+
Signed-off-by: Amit Shah 
Reviewed-by: Jason Cooper 
Signed-off-by: Herbert Xu