Re: [PATCH 1/2] lib: uuid: use RNG device if present

[Torsten Duwe]

On Wed, 16 Dec 2020 11:41:16 +0100
matthias@kernel.org wrote:

> @@ -249,9 +250,22 @@ void gen_rand_uuid(unsigned char *uuid_bin)
>  {
>   u32 ptr[4];
>   struct uuid *uuid = (struct uuid *)ptr;
> - int i;
> -
> - srand(get_ticks() + rand());
> + int i, ret;
> + struct udevice *devp;
> + u8 randv = 0;
> +
> +#if defined(CONFIG_DM_RNG)
> + ret = uclass_get_device(UCLASS_RNG, 0, &devp);
> + if (ret) {
> + ret = dm_rng_read(dev, randv, sizeof(randv));
 ^ ^
same as patch 2/2

> + if (ret < 0)
> + randv = 0;
> + }
> + if (randv)
> + srand(randv);
> + else
> +#endif
> + srand(get_ticks() + rand());
>  
>   /* Set all fields randomly */
>   for (i = 0; i < 4; i++)

[PATCH 1/2] lib: uuid: use RNG device if present

[matthias . bgg]

From: Matthias Brugger 

When calculating a random UUID we use a weak seed.
Use a RNG device if present to increase entropy.

Signed-off-by: Matthias Brugger 
---

 lib/uuid.c | 20 +---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/lib/uuid.c b/lib/uuid.c
index e62d5ca264..219d4b7767 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -15,6 +15,7 @@
 #include 
 #include 
 #include 
+#include 
 
 /*
  * UUID - Universally Unique IDentifier - 128 bits unique number.
@@ -249,9 +250,22 @@ void gen_rand_uuid(unsigned char *uuid_bin)
 {
u32 ptr[4];
struct uuid *uuid = (struct uuid *)ptr;
-   int i;
-
-   srand(get_ticks() + rand());
+   int i, ret;
+   struct udevice *devp;
+   u8 randv = 0;
+
+#if defined(CONFIG_DM_RNG)
+   ret = uclass_get_device(UCLASS_RNG, 0, &devp);
+   if (ret) {
+   ret = dm_rng_read(dev, randv, sizeof(randv));
+   if (ret < 0)
+   randv = 0;
+   }
+   if (randv)
+   srand(randv);
+   else
+#endif
+   srand(get_ticks() + rand());
 
/* Set all fields randomly */
for (i = 0; i < 4; i++)
-- 
2.29.2