net: Use NDRNG device in srand_mac()

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>
This commit is contained in:
Matthias Brugger 2020-12-18 10:28:04 +01:00 committed by Tom Rini
parent 92fdad28cf
commit ea707dc0aa

View File

@ -10,6 +10,8 @@
#define __NET_RAND_H__ #define __NET_RAND_H__
#include <common.h> #include <common.h>
#include <dm/uclass.h>
#include <rng.h>
/* /*
* Return a seed for the PRNG derived from the eth0 MAC address. * 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) 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__ */ #endif /* __NET_RAND_H__ */