Add support for the EFI Random Number Generator Protocol and use it to XOR

random data into the buffer that we feed the kernel.

ok deraadt@

3 files changed, 93 insertions, 6 deletions

diff --git a/sys/arch/arm64/stand/efiboot/Makefile b/sys/arch/arm64/stand/efiboot/Makefile
index b93b19dc7c6..49247115a75 100644
--- a/sys/arch/arm64/stand/efiboot/Makefile
+++ b/sys/arch/arm64/stand/efiboot/Makefile
@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.4 2018/03/31 17:43:53 patrick Exp $
+#	$OpenBSD: Makefile,v 1.5 2018/04/08 13:27:22 kettenis Exp $
 
 NOMAN=		#
 
@@ -8,8 +8,8 @@ PROG=		BOOTAA64.EFI
 OBJFMT=		binary
 INSTALL_STRIP=
 BINDIR=		/usr/mdec
-SRCS=		start.S self_reloc.c efiboot.c conf.c exec.c efidev.c efipxe.c
-SRCS+=		fdt.c
+SRCS=		start.S self_reloc.c efiboot.c conf.c exec.c efidev.c
+SRCS+=		efipxe.c efirng.c fdt.c
 
 S=		${.CURDIR}/../../../..
 EFIDIR=		${S}/stand/efi
@@ -43,7 +43,7 @@ CPPFLAGS+=	-I${S} -I. -I${.CURDIR}
 CPPFLAGS+=	-I${EFIDIR}/include -I${EFIDIR}/include/arm64
 CPPFLAGS+=	-D_STANDALONE
 CPPFLAGS+=	-DSMALL -DSLOW -DNOBYFOUR -D__INTERNAL_LIBSA_CREAD
-CPPFLAGS+=	-DNEEDS_HEAP_H
+CPPFLAGS+=	-DNEEDS_HEAP_H -DFWRANDOM
 COPTS+=		-Wno-attributes -Wno-format
 COPTS+=		-ffreestanding -fno-stack-protector
 COPTS+=		-fshort-wchar -fPIC -fno-builtin
diff --git a/sys/arch/arm64/stand/efiboot/conf.c b/sys/arch/arm64/stand/efiboot/conf.c
index b2e4c8f3caa..5e8fd5fa0e7 100644
--- a/sys/arch/arm64/stand/efiboot/conf.c
+++ b/sys/arch/arm64/stand/efiboot/conf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: conf.c,v 1.14 2018/03/31 17:44:57 patrick Exp $	*/
+/*	$OpenBSD: conf.c,v 1.15 2018/04/08 13:27:22 kettenis Exp $	*/
 
 /*
  * Copyright (c) 1996 Michael Shalayeff
@@ -36,7 +36,7 @@
 #include "efidev.h"
 #include "efipxe.h"
 
-const char version[] = "0.12";
+const char version[] = "0.13";
 int	debug = 0;
 
 struct fs_ops file_system[] = {
diff --git a/sys/arch/arm64/stand/efiboot/efirng.c b/sys/arch/arm64/stand/efiboot/efirng.c
new file mode 100644
index 00000000000..a90f86d57f7
--- /dev/null
+++ b/sys/arch/arm64/stand/efiboot/efirng.c
@@ -0,0 +1,87 @@
+/*	$OpenBSD: efirng.c,v 1.1 2018/04/08 13:27:22 kettenis Exp $	*/
+
+/*
+ * Copyright (c) 2018 Mark Kettenis <kettenis@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);
+}