first and last commit

lib/nonce/library.mk

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+# Copyright (C) 2014 Apple Inc. All rights reserved.
+#
+# This document is the property of Apple Inc.
+# It is considered confidential and proprietary.
+#
+# This document may not be reproduced or transmitted in any form,
+# in whole or in part, without the express written permission of
+# Apple Inc.
+#
+
+LIBNONCE_DIR		:=	$(GET_LOCAL_DIR)
+LIBNONCE_BUILD		:=	$(call TOLIBDIR,$(LIBNONCE_DIR)/LIBNONCE.a)
+COMMONLIBS		+=	LIBNONCE
+
+# Only process the remainder of the makefile if we are building libraries
+#
+ifeq ($(MAKEPHASE),libraries)
+
+LIBNONCE_OBJS		:=	$(LIBNONCE_DIR)/nonce.o
+
+LIBNONCE_OBJS		:=	$(call TOLIBOBJDIR,$(LIBNONCE_OBJS))
+
+ALL_DEPS		+=	$(LIBNONCE_OBJS:%o=%d)
+
+$(LIBNONCE_BUILD):	$(LIBNONCE_OBJS)
+
+endif

lib/nonce/nonce.c

@@ -0,0 +1,210 @@
+/*
+ * Copyright (c) 2012-2015 Apple Inc. All rights reserved.
+ *
+ * This document is the property of Apple Inc.
+ * It is considered confidential and proprietary.
+ *
+ * This document may not be reproduced or transmitted in any form,
+ * in whole or in part, without the express written permission of
+ * Apple Inc.
+ */
+
+#include <stdlib.h>
+
+#include <lib/env.h>
+#include <lib/mib.h>
+#include <lib/nonce.h>
+#include <lib/nvram.h>
+#include <lib/random.h>
+#include <debug.h>
+#include <platform.h>
+#include <sys/hash.h>
+#include <sys/menu.h>
+
+static const char	*kBootNoncePropertyKey = "com.apple.System.boot-nonce";
+static const size_t	kExpectedNonceLength = (sizeof(uint64_t) * 2) + 2;
+
+int
+mobile_ap_nonce_consume_nonce(uint64_t *nonce)
+{
+	const char*	nonce_string;
+	size_t		nonce_length = 0;
+	int		result = 0;
+
+	ASSERT(nonce != NULL);
+
+	*nonce = 0;
+	nonce_string = env_get(kBootNoncePropertyKey);
+
+	if (nonce_string != NULL) {
+		dprintf(DEBUG_SPEW, "%s: nonce_string='%s'\n", __func__, nonce_string);
+		nonce_length = strlen(nonce_string);
+		dprintf(DEBUG_SPEW, "%s: nonce_length='%zu'\n", __func__, nonce_length);
+		if (nonce_length == kExpectedNonceLength) {
+			*nonce = strtoull(nonce_string, NULL, 16);
+			result = 1;
+		} else {
+#if DEBUG_BUILD
+			dprintf(DEBUG_CRITICAL,
+				"%s: nonce value has invalid length %zu %s\n",
+				__func__, nonce_length, nonce_string);
+#else
+			dprintf(DEBUG_CRITICAL,
+				"%s: nonce value has invalid length\n",
+				__func__);
+#endif
+		}
+
+		// The nonce environment variable exists.
+		// Remove it whether it is valid or not.
+		if (env_unset(kBootNoncePropertyKey)) {
+			// Save the updated nvram contents.
+			if (nvram_save() != 0) {
+				dprintf(DEBUG_CRITICAL,
+					"%s: Could not save nvram contents\n",
+					__func__);
+			}
+		} else {
+			dprintf(DEBUG_CRITICAL,
+				"%s: could not clear nonce\n",
+				__func__);
+		}
+	}
+
+	return result;
+}
+
+
+// =============================================================================
+
+static void
+print_usage(int argc, struct cmd_arg *args)
+{
+	printf("USAGE: %s <subcmd>\n\n", ((0 < argc) ? args[0].str : "?"));
+	printf("  Where <subcmd> is one of following\n\n");
+	printf("    get     - read the nonce and clear it, then report its hash and value\n");
+	printf("              if no nonce was previously set, one is generated\n");
+	if (mib_get_bool(kMIBTargetWithEffaceable)) {
+		return;
+	}
+	printf("    clear   - clear the nonce\n");
+	printf("    consume - read the raw nonce, report its hash and value, and comsume it\n");
+	printf("    read    - read the raw nonce, report its hash and value, but don't consume it\n");
+}
+
+static void
+print_nonce_and_hash(uint64_t nonce)
+{
+	uint8_t		hash[HASH_OUTPUT_SIZE];
+	int		idx;
+
+	hash_calculate(&nonce, sizeof(nonce), hash, sizeof(hash));
+
+	printf("boot-nonce: 0x%016llx\n", nonce);
+	printf("boot-nonce hash:");
+	for (idx = 0; idx < HASH_OUTPUT_SIZE; idx++) {
+		printf(" %02X", hash[idx]);
+	}
+	printf("\n");
+}
+
+static int
+get_nonce(void)
+{
+	uint64_t nonce;
+
+	nonce = platform_get_nonce();
+	print_nonce_and_hash(nonce);
+
+	return 0;
+}
+
+static int
+clear_nonce(void)
+{
+	const char*	nonce_string;
+
+	nonce_string = env_get(kBootNoncePropertyKey);
+	if (nonce_string != NULL) {
+		if (env_unset(kBootNoncePropertyKey)) {
+			// Save the updated nvram contents.
+			if (nvram_save() == 0) {
+				printf("Boot nonce cleared\n");
+			} else {
+				printf("Failed to update nvram\n");
+			}
+		} else {
+			printf("Failed to clear boot nonce\n");
+		}
+	} else {
+		printf("Boot nonce not found\n");
+	}
+
+	return 0;
+}
+
+static int
+consume_nonce(void)
+{
+	uint64_t	nonce;
+
+	nonce = platform_consume_nonce();
+	print_nonce_and_hash(nonce);
+
+	return 0;
+}
+
+static int
+read_nonce(void)
+{
+	uint64_t	nonce;
+	const char*	nonce_string;
+	size_t		nonce_length = 0;
+
+	nonce_string = env_get(kBootNoncePropertyKey);
+	if (nonce_string != NULL)
+		nonce_length = strlen(nonce_string);
+
+	if (nonce_length != 0) {
+		// The nonce string must be the exact length of a
+		// 64-bit integer plus 2 for the "0x" prefix.
+		if (nonce_length == kExpectedNonceLength) {
+			nonce = strtoull(nonce_string, NULL, 16);
+			print_nonce_and_hash(nonce);
+		} else {
+			printf("Boot nonce value (%s) has invalid length %zu should be %zu",
+			       nonce_string, nonce_length, kExpectedNonceLength);
+		}
+	} else {
+		printf("Boot nonce not found\n");
+	}
+
+	return 0;
+}
+
+int
+do_nonce(int argc, struct cmd_arg *args)
+{
+	int	err;
+	bool	with_effaceable = mib_get_bool(kMIBTargetWithEffaceable);
+
+	if (1 >= argc) {
+		print_usage(argc, args);
+		err = 0;
+	} else if (0 == strcmp("get", args[1].str)) {
+		err = get_nonce();
+	} else if (!with_effaceable && (0 == strcmp("clear", args[1].str))) {
+		err = clear_nonce();
+	} else if (!with_effaceable && (0 == strcmp("consume", args[1].str))) {
+		err = consume_nonce();
+	} else if (!with_effaceable && (0 == strcmp("read", args[1].str))) {
+		err = read_nonce();
+	} else {
+		print_usage(argc, args);
+		printf("unrecognized subcommand\n");
+		err = -1;
+	}
+
+	return err;
+}
+

lib/nonce/rules.mk

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+# Copyright (C) 2014 Apple, Inc. All rights reserved.
+#
+# This document is the property of Apple, Inc.
+# It is considered confidential and proprietary.
+#
+# This document may not be reproduced or transmitted in any form,
+# in whole or in part, without the express written permission of
+# Apple, Inc.
+#
+
+OPTIONS		+= WITH_NONCE=1
+LIBRARY_MODULES	+= lib/nonce