> From: "Theo de Raadt" <dera...@openbsd.org>
> Date: Sat, 04 May 2019 15:03:50 -0600
>
> Nice.
>
> Mike -- does this collide with your current work, or does it
> not impact it?
This is pretty much completely standalone. The other diff I just
mailed out certainly impacts Mike's work.
Cheers,
Mark
> Mark Kettenis <mark.kette...@xs4all.nl> wrote:
>
> > The UEFI standard defines an (optional) protocol for getting random
> > numbers. A while back I wrote support for this for the arm64
> > bootloader. But we should use this on amd64 as well. I tested that
> > this actually works on a machine with a recent AMD Ryzen APU. Not
> > sure if the firmware implements this using RDRAND or if it uses the
> > random number generator of the integrated crypto unit. Either way,
> > this can't make matters worse since the "entropy" is XORed into the
> > random data buffer.
> >
> > ok?
> >
> >
> > Index: arch/amd64/stand/efiboot/Makefile.common
> > ===================================================================
> > RCS file: /cvs/src/sys/arch/amd64/stand/efiboot/Makefile.common,v
> > retrieving revision 1.14
> > diff -u -p -r1.14 Makefile.common
> > --- arch/amd64/stand/efiboot/Makefile.common 20 Apr 2019 22:59:03
> > -0000 1.14
> > +++ arch/amd64/stand/efiboot/Makefile.common 4 May 2019 20:59:48
> > -0000
> > @@ -11,7 +11,7 @@ EFI_HEAP_LIMIT= 0xc00000
> >
> > LDFLAGS+= -nostdlib -T${.CURDIR}/../${LDSCRIPT} -Bsymbolic -shared
> >
> > -COPTS+= -DEFIBOOT -DNEEDS_HEAP_H -I${.CURDIR}/..
> > +COPTS+= -DEFIBOOT -DFWRANDOM -DNEEDS_HEAP_H -I${.CURDIR}/..
> > COPTS+= -I${EFIDIR}/include -I${S}/stand/boot
> > COPTS+= -ffreestanding -std=gnu99
> > COPTS+= -fshort-wchar -fPIC -mno-red-zone
> > @@ -24,7 +24,7 @@ AFLAGS+= -pipe -fPIC
> >
> > .PATH: ${.CURDIR}/..
> > SRCS+= self_reloc.c
> > -SRCS+= efiboot.c efidev.c efipxe.c
> > +SRCS+= efiboot.c efidev.c efipxe.c efirng.c
> > SRCS+= conf.c
> >
> > .PATH: ${S}/stand/boot
> > Index: arch/amd64/stand/efiboot/efirng.c
> > ===================================================================
> > RCS file: arch/amd64/stand/efiboot/efirng.c
> > diff -N arch/amd64/stand/efiboot/efirng.c
> > --- /dev/null 1 Jan 1970 00:00:00 -0000
> > +++ arch/amd64/stand/efiboot/efirng.c 4 May 2019 20:59:48 -0000
> > @@ -0,0 +1,87 @@
> > +/* $OpenBSD: efirng.c,v 1.1 2018/04/08 13:27:22 kettenis Exp $ */
> > +
> > +/*
> > + * Copyright (c) 2018 Mark Kettenis <kette...@openbsd.org>
> > + *
> > + * Permission to use, copy, modify, and distribute this software for any
> > + * purpose with or without fee is hereby granted, provided that the above
> > + * copyright notice and this permission notice appear in all copies.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
> > + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
> > + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
> > + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> > + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
> > + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
> > + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> > + */
> > +
> > +#include <sys/param.h>
> > +
> > +#include <efi.h>
> > +#include <efiapi.h>
> > +
> > +#include "eficall.h"
> > +#include "libsa.h"
> > +
> > +extern EFI_BOOT_SERVICES *BS;
> > +
> > +/* Random Number Generator Protocol */
> > +
> > +#define EFI_RNG_PROTOCOL_GUID \
> > + { 0x3152bca5, 0xeade, 0x433d, {0x86, 0x2e, 0xc0, 0x1c, 0xdc, 0x29,
> > 0x1f, 0x44} }
> > +
> > +INTERFACE_DECL(_EFI_RNG_PROTOCOL);
> > +
> > +typedef EFI_GUID EFI_RNG_ALGORITHM;
> > +
> > +typedef
> > +EFI_STATUS
> > +(EFIAPI *EFI_RNG_GET_INFO) (
> > + IN struct _EFI_RNG_PROTOCOL *This,
> > + IN OUT UINTN *RNGAlgorithmListSize,
> > + OUT EFI_RNG_ALGORITHM *RNGAlgorithmList
> > + );
> > +
> > +typedef
> > +EFI_STATUS
> > +(EFIAPI *EFI_RNG_GET_RNG) (
> > + IN struct _EFI_RNG_PROTOCOL *This,
> > + IN EFI_RNG_ALGORITHM *RNGAlgorithm, OPTIONAL
> > + IN UINTN RNGValueLength,
> > + OUT UINT8 *RNGValue
> > + );
> > +
> > +typedef struct _EFI_RNG_PROTOCOL {
> > + EFI_RNG_GET_INFO GetInfo;
> > + EFI_RNG_GET_RNG GetRNG;
> > +} EFI_RNG_PROTOCOL;
> > +
> > +static EFI_GUID rng_guid = EFI_RNG_PROTOCOL_GUID;
> > +
> > +void
> > +fwrandom(char *buf, size_t buflen)
> > +{
> > + EFI_STATUS status;
> > + EFI_RNG_PROTOCOL *rng = NULL;
> > + UINT8 *random;
> > + size_t i;
> > +
> > + status = EFI_CALL(BS->LocateProtocol, &rng_guid, NULL, (void **)&rng);
> > + if (rng == NULL || EFI_ERROR(status))
> > + return;
> > +
> > + random = alloc(buflen);
> > +
> > + status = EFI_CALL(rng->GetRNG, rng, NULL, buflen, random);
> > + if (EFI_ERROR(status)) {
> > + printf("RNG GetRNG() failed (%d)\n", status);
> > + goto out;
> > + }
> > +
> > + for (i = 0; i < buflen; i++)
> > + buf[i] ^= random[i];
> > +
> > +out:
> > + free(random, buflen);
> > +}
> >
>
>
