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

Browse Source 
Pull crypto fixes from Herbert Xu:
 "This push fixes a boot hang in virt guests when the virtio RNG is
  enabled"

* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  hwrng: virtio - ensure reads happen after successful probe
  hwrng: fetch randomness only after device init
This commit is contained in:
Linus Torvalds 2014-07-18 20:25:54 -10:00
commit 4e10627529
2 changed files with 49 additions and 8 deletions
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47
drivers/char/hw_random/core.c
View File

@ -55,16 +55,41 @@ static DEFINE_MUTEX(rng_mutex);
static int data_avail;
static u8 *rng_buffer;
static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
int wait);
static size_t rng_buffer_size(void)
{
return SMP_CACHE_BYTES < 32 ? 32 : SMP_CACHE_BYTES;
}
static void add_early_randomness(struct hwrng *rng)
{
unsigned char bytes[16];
int bytes_read;
/*
* Currently only virtio-rng cannot return data during device
* probe, and that's handled in virtio-rng.c itself. If there
* are more such devices, this call to rng_get_data can be
* made conditional here instead of doing it per-device.
*/
bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1);
if (bytes_read > 0)
add_device_randomness(bytes, bytes_read);
}
static inline int hwrng_init(struct hwrng *rng)
{
if (!rng->init)
return 0;
return rng->init(rng);
if (rng->init) {
int ret;
ret = rng->init(rng);
if (ret)
return ret;
}
add_early_randomness(rng);
return 0;
}
static inline void hwrng_cleanup(struct hwrng *rng)
@ -304,8 +329,6 @@ int hwrng_register(struct hwrng *rng)
{
int err = -EINVAL;
struct hwrng *old_rng, *tmp;
unsigned char bytes[16];
int bytes_read;
if (rng->name == NULL ||
(rng->data_read == NULL && rng->read == NULL))
@ -347,9 +370,17 @@ int hwrng_register(struct hwrng *rng)
INIT_LIST_HEAD(&rng->list);
list_add_tail(&rng->list, &rng_list);
bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1);
if (bytes_read > 0)
add_device_randomness(bytes, bytes_read);
if (old_rng && !rng->init) {
/*
* Use a new device's input to add some randomness to
* the system. If this rng device isn't going to be
* used right away, its init function hasn't been
* called yet; so only use the randomness from devices
* that don't need an init callback.
*/
add_early_randomness(rng);
}
out_unlock:
mutex_unlock(&rng_mutex);
out:

10
drivers/char/hw_random/virtio-rng.c
View File

@ -38,6 +38,8 @@ struct virtrng_info {
int index;
};
static bool probe_done;
static void random_recv_done(struct virtqueue *vq)
{
struct virtrng_info *vi = vq->vdev->priv;
@ -67,6 +69,13 @@ static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
int ret;
struct virtrng_info *vi = (struct virtrng_info *)rng->priv;
/*
* Don't ask host for data till we're setup. This call can
* happen during hwrng_register(), after commit d9e7972619.
*/
if (unlikely(!probe_done))
return 0;
if (!vi->busy) {
vi->busy = true;
init_completion(&vi->have_data);
@ -137,6 +146,7 @@ static int probe_common(struct virtio_device *vdev)
return err;
}
probe_done = true;
return 0;
}