Hi! Thanks for explanation. The feature's name is very misleading...
On 9/3/16, Jared McNeill <[email protected]> wrote: > Hi Oliver -- > > It's really just a serial number. The Allwinner A20 datasheet refers to it > as a root key, later ones such as A83T refer to it as chip ID. U-Boot > uses the same process to generate MAC addresses for all Allwinner boards. > > Cheers, > Jared > > > On Sat, 3 Sep 2016, Oliver Pinter wrote: > >> Hi! >> >> On 9/3/16, Jared McNeill <[email protected]> wrote: >>> Author: jmcneill >>> Date: Sat Sep 3 15:28:09 2016 >>> New Revision: 305354 >>> URL: https://svnweb.freebsd.org/changeset/base/305354 >>> >>> Log: >>> Use the root key in the Security ID EFUSE (when valid) to generate a >>> MAC address instead of creating a random one each boot. >> >> Could you please describe a little more about this root key? What is >> it? What's the main purpose? Is is a crypto root key? >> >>> >>> Modified: >>> head/sys/arm/allwinner/if_awg.c >>> >>> Modified: head/sys/arm/allwinner/if_awg.c >>> ============================================================================== >>> --- head/sys/arm/allwinner/if_awg.c Sat Sep 3 15:26:28 2016 >>> (r305353) >>> +++ head/sys/arm/allwinner/if_awg.c Sat Sep 3 15:28:09 2016 >>> (r305354) >>> @@ -62,6 +62,7 @@ __FBSDID("$FreeBSD$"); >>> #include <dev/ofw/ofw_bus_subr.h> >>> >>> #include <arm/allwinner/if_awgreg.h> >>> +#include <arm/allwinner/aw_sid.h> >>> #include <dev/mii/mii.h> >>> #include <dev/mii/miivar.h> >>> >>> @@ -1277,6 +1278,7 @@ awg_get_eaddr(device_t dev, uint8_t *ead >>> { >>> struct awg_softc *sc; >>> uint32_t maclo, machi, rnd; >>> + u_char rootkey[16]; >>> >>> sc = device_get_softc(dev); >>> >>> @@ -1285,9 +1287,19 @@ awg_get_eaddr(device_t dev, uint8_t *ead >>> >>> if (maclo == 0xffffffff && machi == 0xffff) { >>> /* MAC address in hardware is invalid, create one */ >>> - rnd = arc4random(); >>> - maclo = 0x00f2 | (rnd & 0xffff0000); >>> - machi = rnd & 0xffff; >>> + if (aw_sid_get_rootkey(rootkey) == 0 && >>> + (rootkey[3] | rootkey[12] | rootkey[13] | rootkey[14] | >>> + rootkey[15]) != 0) { >>> + /* MAC address is derived from the root key in SID */ >>> + maclo = (rootkey[13] << 24) | (rootkey[12] << 16) | >>> + (rootkey[3] << 8) | 0x02; >>> + machi = (rootkey[15] << 8) | rootkey[14]; >>> + } else { >>> + /* Create one */ >>> + rnd = arc4random(); >>> + maclo = 0x00f2 | (rnd & 0xffff0000); >>> + machi = rnd & 0xffff; >>> + } >>> } >>> >>> eaddr[0] = maclo & 0xff; >>> _______________________________________________ >>> [email protected] mailing list >>> https://lists.freebsd.org/mailman/listinfo/svn-src-head >>> To unsubscribe, send any mail to "[email protected]" >>> >> >> > _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
