diff mbox series

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

Message ID 20201216104117.10836-2-matthias.bgg@kernel.org
State Superseded
Delegated to: Tom Rini
Headers show
Series Use RNG to get random behaviour | expand

Commit Message

Matthias Brugger Dec. 16, 2020, 10:41 a.m. UTC 
From: Matthias Brugger <mbrugger@suse.com>

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

Signed-off-by: Matthias Brugger <mbrugger@suse.com>
---

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

Comments

Torsten Duwe Dec. 16, 2020, 1:22 p.m. UTC | #1 
On Wed, 16 Dec 2020 11:41:16 +0100
matthias.bgg@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++)
diff mbox series

Patch

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 <asm/io.h>
 #include <part_efi.h>
 #include <malloc.h>
+#include <rng.h>
 
 /*
  * 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++)