[PATCH][RESEND 3] hwrng: add randomness to system from rng sources
[Posted March 12, 2014 by jake]
| From: |
| Kees Cook <keescook-AT-chromium.org> |
| To: |
| linux-kernel-AT-vger.kernel.org |
| Subject: |
| [PATCH][RESEND 3] hwrng: add randomness to system from rng sources |
| Date: |
| Mon, 3 Mar 2014 15:51:48 -0800 |
| Message-ID: |
| <20140303235148.GA7601@www.outflux.net> |
| Cc: |
| Matt Mackall <mpm-AT-selenic.com>, Herbert Xu <herbert-AT-gondor.apana.org.au>, Rusty Russell <rusty-AT-rustcorp.com.au>, Satoru Takeuchi <satoru.takeuchi-AT-gmail.com>, linux-crypto-AT-vger.kernel.org, "Theodore Ts'o" <tytso-AT-mit.edu>, Andrew Morton <akpm-AT-linux-foundation.org> |
| Archive‑link: | |
Article |
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>
---
drivers/char/hw_random/core.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index a0f7724852eb..6e5bb68a708c 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -41,6 +41,7 @@
#include <linux/miscdevice.h>
#include <linux/delay.h>
#include <linux/slab.h>
+#include <linux/random.h>
#include <asm/uaccess.h>
@@ -305,6 +306,8 @@ int hwrng_register(struct hwrng *rng)
int must_register_misc;
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))
@@ -348,6 +351,10 @@ 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);
out_unlock:
mutex_unlock(&rng_mutex);
out:
--
1.7.9.5
--
Kees Cook
Chrome OS Security
