Date: Sat, 3 Sep 2016 14:06:37 -0300 (ADT) From: Jared McNeill <jmcneill@invisible.ca> To: Oliver Pinter <oliver.pinter@hardenedbsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r305354 - head/sys/arm/allwinner Message-ID: <alpine.DEB.2.11.1609031358300.641@dis.invisible.ca> In-Reply-To: <CAPQ4ffs%2BdexyyewdwLg1Hp1j30Yn5Lfu5uajzVy99sgwBjNXAA@mail.gmail.com> References: <201609031528.u83FS91u017461@repo.freebsd.org> <CAPQ4ffs%2BdexyyewdwLg1Hp1j30Yn5Lfu5uajzVy99sgwBjNXAA@mail.gmail.com>
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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 <jmcneill@freebsd.org> 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; >> _______________________________________________ >> svn-src-head@freebsd.org mailing list >> https://lists.freebsd.org/mailman/listinfo/svn-src-head >> To unsubscribe, send any mail to "svn-src-head-unsubscribe@freebsd.org" >> > >
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