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.
Also, the virtio-rng device does not behave properly when this call is made in its probe() routine - the virtio core sets the DRIVER_OK status bit only on a successful probe, which means the host ignores all communication from the guest, and the guest insmod or boot process just sits there doing nothing. 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 isn't made. CC: Kees Cook <[email protected]> CC: Jason Cooper <[email protected]> CC: Herbert Xu <[email protected]> CC: <[email protected]> # For 3.15 only Signed-off-by: Amit Shah <[email protected]> --- drivers/char/hw_random/core.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 334601c..3f3941d 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -347,9 +347,11 @@ 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 (!rng->init) { + bytes_read = rng_get_data(rng, bytes, sizeof(bytes), 1); + if (bytes_read > 0) + add_device_randomness(bytes, bytes_read); + } out_unlock: mutex_unlock(&rng_mutex); out: -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
