| Message ID | 20201216104117.10836-3-matthias.bgg@kernel.org |
|---|---|
| State | Superseded |
| Delegated to: | Tom Rini |
| Headers | show |
| Series | Use RNG to get random behaviour | expand |
On Wed, 16 Dec 2020 11:41:17 +0100 matthias.bgg@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> > > --- > > net/net_rand.h | 18 +++++++++++++++++- > 1 file changed, 17 insertions(+), 1 deletion(-) > > diff --git a/net/net_rand.h b/net/net_rand.h > index 4bf9bd817e..600c3d825e 100644 > --- a/net/net_rand.h > +++ b/net/net_rand.h > @@ -10,6 +10,7 @@ > #define __NET_RAND_H__ > > #include <common.h> > +#include <rng.h> > > /* > * Return a seed for the PRNG derived from the eth0 MAC address. > @@ -37,7 +38,22 @@ static inline unsigned int seed_mac(void) > */ > static inline void srand_mac(void) > { > - srand(seed_mac()); > +#if defined(CONFIG_DM_RNG) > + int ret; > + struct udevice *devp; > + u32 randv = 0; > + > + ret = uclass_get_device(UCLASS_RNG, 0, &devp); > + if (ret) { > + ret = dm_rng_read(dev, randv, sizeof(randv)); Haven't tested this (yet), but shouldn't this be ret = dm_rng_read(devp, &randv, sizeof(randv)); ^ ^ ? > + if (ret < 0) > + randv = 0; > + } > + if (randv) > + srand(randv); > + else > +#endif > + srand(seed_mac()); > } > > #endif /* __NET_RAND_H__ */
On 16/12/2020 14:20, Torsten Duwe wrote: > On Wed, 16 Dec 2020 11:41:17 +0100 > matthias.bgg@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> >> >> --- >> >> net/net_rand.h | 18 +++++++++++++++++- >> 1 file changed, 17 insertions(+), 1 deletion(-) >> >> diff --git a/net/net_rand.h b/net/net_rand.h >> index 4bf9bd817e..600c3d825e 100644 >> --- a/net/net_rand.h >> +++ b/net/net_rand.h >> @@ -10,6 +10,7 @@ >> #define __NET_RAND_H__ >> >> #include <common.h> >> +#include <rng.h> >> >> /* >> * Return a seed for the PRNG derived from the eth0 MAC address. >> @@ -37,7 +38,22 @@ static inline unsigned int seed_mac(void) >> */ >> static inline void srand_mac(void) >> { >> - srand(seed_mac()); >> +#if defined(CONFIG_DM_RNG) >> + int ret; >> + struct udevice *devp; >> + u32 randv = 0; >> + >> + ret = uclass_get_device(UCLASS_RNG, 0, &devp); >> + if (ret) { >> + ret = dm_rng_read(dev, randv, sizeof(randv)); > Haven't tested this (yet), but shouldn't this be > ret = dm_rng_read(devp, &randv, sizeof(randv)); > ^ ^ ? Ups, yes you are right. I'll send a v2. Regards, Matthias
diff --git a/net/net_rand.h b/net/net_rand.h index 4bf9bd817e..600c3d825e 100644 --- a/net/net_rand.h +++ b/net/net_rand.h @@ -10,6 +10,7 @@ #define __NET_RAND_H__ #include <common.h> +#include <rng.h> /* * Return a seed for the PRNG derived from the eth0 MAC address. @@ -37,7 +38,22 @@ static inline unsigned int seed_mac(void) */ static inline void srand_mac(void) { - srand(seed_mac()); +#if defined(CONFIG_DM_RNG) + int ret; + struct udevice *devp; + u32 randv = 0; + + 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(seed_mac()); } #endif /* __NET_RAND_H__ */