hwrng: add randomness to system from rng sources

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 <[email protected]> Reviewed-by: Jason Cooper <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
AnTAVR · Mar 10, 2014 · d9e7972 · d9e7972
1 parent 04d088c
commit d9e7972
Showing 1 changed file with 7 additions and 0 deletions.
diff --git 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>
 
 
@@ -304,6 +305,8 @@ 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))
@@ -344,6 +347,10 @@ 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: