[PATCH v3 0/2] Use RNG to get random behaviour

[PATCH v3 0/2] Use RNG to get random behaviour

[matthias.bgg at kernel.org]

From: Matthias Brugger <mbrugger@suse.com>

For now bootp and uuid code use a weak seed for generating random data.
U-Boot as support for RNG devices now, so we should change to code to
use them if they are present. This will help mitigate issues like seen
in CVE-2019-11690.

Changes in v3:
- use IS_ENABLED instead of #if
- use 4 byte for entropy
- use IS_ENABLED instead of #if

Changes in v2:
- fix dm_rng_read() parameters
- add missing include
- fix dm_rng_read() parameters
- add missing include file

Matthias Brugger (2):
  lib: uuid: use RNG device if present
  net: Use NDRNG device in srand_mac()

 lib/uuid.c     | 21 ++++++++++++++++++---
 net/net_rand.h | 19 ++++++++++++++++++-
 2 files changed, 36 insertions(+), 4 deletions(-)

-- 
2.29.2

[PATCH v3 1/2] lib: uuid: use RNG device if present

[matthias.bgg at kernel.org]

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>

---

Changes in v3:
- use IS_ENABLED instead of #if
- use 4 byte for entropy

Changes in v2:
- fix dm_rng_read() parameters
- add missing include

 lib/uuid.c | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/lib/uuid.c b/lib/uuid.c
index e62d5ca264..23af2b4800 100644
--- a/lib/uuid.c
+++ b/lib/uuid.c
@@ -15,6 +15,8 @@
 #include <asm/io.h>
 #include <part_efi.h>
 #include <malloc.h>
+#include <dm/uclass.h>
+#include <rng.h>
 
 /*
  * UUID - Universally Unique IDentifier - 128 bits unique number.
@@ -249,9 +251,22 @@ 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;
+	u32 randv = 0;
+
+	if (IS_ENABLED(CONFIG_DM_RNG)) {
+		ret = uclass_get_device(UCLASS_RNG, 0, &devp);
+		if (ret) {
+			ret = dm_rng_read(devp, &randv, sizeof(randv));
+			if (ret < 0)
+				randv = 0;
+		}
+	}
+	if (randv)
+		srand(randv);
+	else
+		srand(get_ticks() + rand());
 
 	/* Set all fields randomly */
 	for (i = 0; i < 4; i++)
-- 
2.29.2

[PATCH v3 2/2] net: Use NDRNG device in srand_mac()

[matthias.bgg at kernel.org]

From: Matthias Brugger <mbrugger@suse.com>

When calling srand_mac we use a weak seed dependent on the
mac address. If present, use a RNG device instead to incerase entropy.

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

---

Changes in v3:
- use IS_ENABLED instead of #if

Changes in v2:
- fix dm_rng_read() parameters
- add missing include file

 net/net_rand.h | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/net/net_rand.h b/net/net_rand.h
index 4bf9bd817e..6a52cda85e 100644
--- a/net/net_rand.h
+++ b/net/net_rand.h
@@ -10,6 +10,8 @@
 #define __NET_RAND_H__
 
 #include <common.h>
+#include <dm/uclass.h>
+#include <rng.h>
 
 /*
  * Return a seed for the PRNG derived from the eth0 MAC address.
@@ -37,7 +39,22 @@ static inline unsigned int seed_mac(void)
  */
 static inline void srand_mac(void)
 {
-	srand(seed_mac());
+	int ret;
+	struct udevice *devp;
+	u32 randv = 0;
+
+	if (IS_ENABLED(CONFIG_DM_RNG)) {
+		ret = uclass_get_device(UCLASS_RNG, 0, &devp);
+		if (ret) {
+			ret = dm_rng_read(devp, &randv, sizeof(randv));
+			if (ret < 0)
+				randv = 0;
+		}
+	}
+	if (randv)
+		srand(randv);
+	else
+		srand(seed_mac());
 }
 
 #endif /* __NET_RAND_H__ */
-- 
2.29.2

[PATCH v3 1/2] lib: uuid: use RNG device if present

[Torsten Duwe]

On Fri, 18 Dec 2020 10:28:03 +0100
matthias.bgg at kernel.org wrote:

> 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>

Reviewed-by: Torsten Duwe <duwe@suse.de>

[PATCH v3 2/2] net: Use NDRNG device in srand_mac()

[Torsten Duwe]

On Fri, 18 Dec 2020 10:28:04 +0100
matthias.bgg at kernel.org wrote:

> From: Matthias Brugger <mbrugger@suse.com>
> 
> When calling srand_mac we use a weak seed dependent on the
> mac address. If present, use a RNG device instead to incerase entropy.
> 
> Signed-off-by: Matthias Brugger <mbrugger@suse.com>

Reviewed-by: Torsten Duwe <duwe@suse.de>

[PATCH v3 1/2] lib: uuid: use RNG device if present

[Tom Rini]

On Fri, Dec 18, 2020 at 10:28:03AM +0100, matthias.bgg at kernel.org wrote:

> 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>
> Reviewed-by: Torsten Duwe <duwe@suse.de>

Applied to u-boot/master, thanks!

-- 
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 659 bytes
Desc: not available
URL: <https://lists.denx.de/pipermail/u-boot/attachments/20210119/6e9947ad/attachment.sig>

[PATCH v3 2/2] net: Use NDRNG device in srand_mac()

[Tom Rini]

On Fri, Dec 18, 2020 at 10:28:04AM +0100, matthias.bgg at kernel.org wrote:

> From: Matthias Brugger <mbrugger@suse.com>
> 
> When calling srand_mac we use a weak seed dependent on the
> mac address. If present, use a RNG device instead to incerase entropy.
> 
> Signed-off-by: Matthias Brugger <mbrugger@suse.com>
> Reviewed-by: Torsten Duwe <duwe@suse.de>

Applied to u-boot/master, thanks!

-- 
Tom
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 659 bytes
Desc: not available
URL: <https://lists.denx.de/pipermail/u-boot/attachments/20210119/d441b15f/attachment.sig>

Re: [PATCH v3 1/2] lib: uuid: use RNG device if present

[Patrick DELAUNAY]

Hi

On 12/18/20 10:28 AM, matthias.bgg@kernel.org wrote:
> 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>
>
> ---
>
> Changes in v3:
> - use IS_ENABLED instead of #if
> - use 4 byte for entropy
>
> Changes in v2:
> - fix dm_rng_read() parameters
> - add missing include
>
>   lib/uuid.c | 21 ++++++++++++++++++---
>   1 file changed, 18 insertions(+), 3 deletions(-)
>
> diff --git a/lib/uuid.c b/lib/uuid.c
> index e62d5ca264..23af2b4800 100644
> --- a/lib/uuid.c
> +++ b/lib/uuid.c
> @@ -15,6 +15,8 @@
>   #include <asm/io.h>
>   #include <part_efi.h>
>   #include <malloc.h>
> +#include <dm/uclass.h>
> +#include <rng.h>
>   
>   /*
>    * UUID - Universally Unique IDentifier - 128 bits unique number.
> @@ -249,9 +251,22 @@ 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;
> +	u32 randv = 0;
> +
> +	if (IS_ENABLED(CONFIG_DM_RNG)) {
> +		ret = uclass_get_device(UCLASS_RNG, 0, &devp);
> +		if (ret) {

For information, as this patch already merged
here we need to test if ret == 0:

+ if (!ret) {


I push a patch to correct this test:

"lib: uuid: fix the test on RNG device presence"

http://patchwork.ozlabs.org/project/uboot/patch/20211022170544.1.Ib218a8a747f99cab44c3fac6af649f17f003b2e2@changeid/


> +			ret = dm_rng_read(devp, &randv, sizeof(randv));
> +			if (ret < 0)
> +				randv = 0;
> +		}
> +	}
> +	if (randv)
> +		srand(randv);
> +	else
> +		srand(get_ticks() + rand());
>   
>   	/* Set all fields randomly */
>   	for (i = 0; i < 4; i++)

Regards

Patrick