cmd: avb2.0: avb command for performing verification

Enable a "avb" command to execute Android Verified
Boot 2.0 operations. It includes such subcommands:
  avb init - initialize avb2 subsystem
  avb read_rb - read rollback index
  avb write_rb - write rollback index
  avb is_unlocked - check device lock state
  avb get_uuid - read and print uuid of a partition
  avb read_part - read data from partition
  avb read_part_hex - read data from partition and output to stdout
  avb write_part - write data to partition
  avb verify - run full verification chain

Signed-off-by: Igor Opaniuk <igor.opaniuk@linaro.org>

cmd/Kconfig

@@ -1754,6 +1754,22 @@ config CMD_TRACE
 	  for analsys (e.g. using bootchart). See doc/README.trace for full
 	  details.
 
+config CMD_AVB
+	bool "avb - Android Verified Boot 2.0 operations"
+	depends on LIBAVB
+	default n
+	help
+	  Enables a "avb" command to perform verification of partitions using
+	  Android Verified Boot 2.0 functionality. It includes such subcommands:
+	    avb init - initialize avb2 subsystem
+	    avb read_rb - read rollback index
+	    avb write_rb - write rollback index
+	    avb is_unlocked - check device lock state
+	    avb get_uuid - read and print uuid of a partition
+	    avb read_part - read data from partition
+	    avb read_part_hex - read data from partition and output to stdout
+	    avb write_part - write data to partition
+	    avb verify - run full verification chain
 endmenu
 
 config CMD_UBI

cmd/Makefile

@@ -155,6 +155,9 @@ obj-$(CONFIG_CMD_REGULATOR) += regulator.o
 
 obj-$(CONFIG_CMD_BLOB) += blob.o
 
+# Android Verified Boot 2.0
+obj-$(CONFIG_CMD_AVB) += avb.o
+
 obj-$(CONFIG_X86) += x86/
 endif # !CONFIG_SPL_BUILD
 

cmd/avb.c

@@ -0,0 +1,357 @@
+
+/*
+ * (C) Copyright 2018, Linaro Limited
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <avb_verify.h>
+#include <command.h>
+#include <image.h>
+#include <malloc.h>
+#include <mmc.h>
+
+#define AVB_BOOTARGS	"avb_bootargs"
+static struct AvbOps *avb_ops;
+
+static const char * const requested_partitions[] = {"boot",
+					     "system",
+					     "vendor",
+					     NULL};
+
+int do_avb_init(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	unsigned long mmc_dev;
+
+	if (argc != 2)
+		return CMD_RET_USAGE;
+
+	mmc_dev = simple_strtoul(argv[1], NULL, 16);
+
+	if (avb_ops)
+		avb_ops_free(avb_ops);
+
+	avb_ops = avb_ops_alloc(mmc_dev);
+	if (avb_ops)
+		return CMD_RET_SUCCESS;
+
+	return CMD_RET_FAILURE;
+}
+
+int do_avb_read_part(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	const char *part;
+	s64 offset;
+	size_t bytes, bytes_read = 0;
+	void *buffer;
+
+	if (!avb_ops) {
+		printf("AVB 2.0 is not initialized, please run 'avb init'\n");
+		return CMD_RET_USAGE;
+	}
+
+	if (argc != 5)
+		return CMD_RET_USAGE;
+
+	part = argv[1];
+	offset = simple_strtoul(argv[2], NULL, 16);
+	bytes = simple_strtoul(argv[3], NULL, 16);
+	buffer = (void *)simple_strtoul(argv[4], NULL, 16);
+
+	if (avb_ops->read_from_partition(avb_ops, part, offset, bytes,
+					 buffer, &bytes_read) ==
+					 AVB_IO_RESULT_OK) {
+		printf("Read %zu bytes\n", bytes_read);
+		return CMD_RET_SUCCESS;
+	}
+
+	return CMD_RET_FAILURE;
+}
+
+int do_avb_read_part_hex(cmd_tbl_t *cmdtp, int flag, int argc,
+			 char *const argv[])
+{
+	const char *part;
+	s64 offset;
+	size_t bytes, bytes_read = 0;
+	char *buffer;
+
+	if (!avb_ops) {
+		printf("AVB 2.0 is not initialized, please run 'avb init'\n");
+		return CMD_RET_USAGE;
+	}
+
+	if (argc != 4)
+		return CMD_RET_USAGE;
+
+	part = argv[1];
+	offset = simple_strtoul(argv[2], NULL, 16);
+	bytes = simple_strtoul(argv[3], NULL, 16);
+
+	buffer = malloc(bytes);
+	if (!buffer) {
+		printf("Failed to tlb_allocate buffer for data\n");
+		return CMD_RET_FAILURE;
+	}
+	memset(buffer, 0, bytes);
+
+	if (avb_ops->read_from_partition(avb_ops, part, offset, bytes, buffer,
+					 &bytes_read) == AVB_IO_RESULT_OK) {
+		printf("Requested %zu, read %zu bytes\n", bytes, bytes_read);
+		printf("Data: ");
+		for (int i = 0; i < bytes_read; i++)
+			printf("%02X", buffer[i]);
+
+		printf("\n");
+
+		free(buffer);
+		return CMD_RET_SUCCESS;
+	}
+
+	free(buffer);
+	return CMD_RET_FAILURE;
+}
+
+int do_avb_write_part(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	const char *part;
+	s64 offset;
+	size_t bytes;
+	void *buffer;
+
+	if (!avb_ops) {
+		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		return CMD_RET_FAILURE;
+	}
+
+	if (argc != 5)
+		return CMD_RET_USAGE;
+
+	part = argv[1];
+	offset = simple_strtoul(argv[2], NULL, 16);
+	bytes = simple_strtoul(argv[3], NULL, 16);
+	buffer = (void *)simple_strtoul(argv[4], NULL, 16);
+
+	if (avb_ops->write_to_partition(avb_ops, part, offset, bytes, buffer) ==
+	    AVB_IO_RESULT_OK) {
+		printf("Wrote %zu bytes\n", bytes);
+		return CMD_RET_SUCCESS;
+	}
+
+	return CMD_RET_FAILURE;
+}
+
+int do_avb_read_rb(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	size_t index;
+	u64 rb_idx;
+
+	if (!avb_ops) {
+		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		return CMD_RET_FAILURE;
+	}
+
+	if (argc != 2)
+		return CMD_RET_USAGE;
+
+	index = (size_t)simple_strtoul(argv[1], NULL, 16);
+
+	if (avb_ops->read_rollback_index(avb_ops, index, &rb_idx) ==
+	    AVB_IO_RESULT_OK) {
+		printf("Rollback index: %llu\n", rb_idx);
+		return CMD_RET_SUCCESS;
+	}
+	return CMD_RET_FAILURE;
+}
+
+int do_avb_write_rb(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	size_t index;
+	u64 rb_idx;
+
+	if (!avb_ops) {
+		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		return CMD_RET_FAILURE;
+	}
+
+	if (argc != 3)
+		return CMD_RET_USAGE;
+
+	index = (size_t)simple_strtoul(argv[1], NULL, 16);
+	rb_idx = simple_strtoul(argv[2], NULL, 16);
+
+	if (avb_ops->write_rollback_index(avb_ops, index, rb_idx) ==
+	    AVB_IO_RESULT_OK)
+		return CMD_RET_SUCCESS;
+
+	return CMD_RET_FAILURE;
+}
+
+int do_avb_get_uuid(cmd_tbl_t *cmdtp, int flag,
+		    int argc, char * const argv[])
+{
+	const char *part;
+	char buffer[UUID_STR_LEN + 1];
+
+	if (!avb_ops) {
+		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		return CMD_RET_FAILURE;
+	}
+
+	if (argc != 2)
+		return CMD_RET_USAGE;
+
+	part = argv[1];
+
+	if (avb_ops->get_unique_guid_for_partition(avb_ops, part, buffer,
+						   UUID_STR_LEN + 1) ==
+						   AVB_IO_RESULT_OK) {
+		printf("'%s' UUID: %s\n", part, buffer);
+		return CMD_RET_SUCCESS;
+	}
+
+	return CMD_RET_FAILURE;
+}
+
+int do_avb_verify_part(cmd_tbl_t *cmdtp, int flag,
+		       int argc, char *const argv[])
+{
+	AvbSlotVerifyResult slot_result;
+	AvbSlotVerifyData *out_data;
+
+	bool unlocked = false;
+	int res = CMD_RET_FAILURE;
+
+	if (!avb_ops) {
+		printf("AVB 2.0 is not initialized, run 'avb init' first\n");
+		return CMD_RET_FAILURE;
+	}
+
+	if (argc != 1)
+		return CMD_RET_USAGE;
+
+	printf("## Android Verified Boot 2.0 version %s\n",
+	       avb_version_string());
+
+	if (avb_ops->read_is_device_unlocked(avb_ops, &unlocked) !=
+	    AVB_IO_RESULT_OK) {
+		printf("Can't determine device lock state.\n");
+		return CMD_RET_FAILURE;
+	}
+
+	slot_result =
+		avb_slot_verify(avb_ops,
+				requested_partitions,
+				"",
+				unlocked,
+				AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE,
+				&out_data);
+
+	switch (slot_result) {
+	case AVB_SLOT_VERIFY_RESULT_OK:
+		printf("Verification passed successfully\n");
+
+		/* export additional bootargs to AVB_BOOTARGS env var */
+		env_set(AVB_BOOTARGS, out_data->cmdline);
+
+		res = CMD_RET_SUCCESS;
+		break;
+	case AVB_SLOT_VERIFY_RESULT_ERROR_VERIFICATION:
+		printf("Verification failed\n");
+		break;
+	case AVB_SLOT_VERIFY_RESULT_ERROR_IO:
+		printf("I/O error occurred during verification\n");
+		break;
+	case AVB_SLOT_VERIFY_RESULT_ERROR_OOM:
+		printf("OOM error occurred during verification\n");
+		break;
+	case AVB_SLOT_VERIFY_RESULT_ERROR_INVALID_METADATA:
+		printf("Corrupted dm-verity metadata detected\n");
+		break;
+	case AVB_SLOT_VERIFY_RESULT_ERROR_UNSUPPORTED_VERSION:
+		printf("Unsupported version avbtool was used\n");
+		break;
+	case AVB_SLOT_VERIFY_RESULT_ERROR_ROLLBACK_INDEX:
+		printf("Checking rollback index failed\n");
+		break;
+	case AVB_SLOT_VERIFY_RESULT_ERROR_PUBLIC_KEY_REJECTED:
+		printf("Public key was rejected\n");
+		break;
+	default:
+		printf("Unknown error occurred\n");
+	}
+
+	return res;
+}
+
+int do_avb_is_unlocked(cmd_tbl_t *cmdtp, int flag,
+		       int argc, char * const argv[])
+{
+	bool unlock;
+
+	if (!avb_ops) {
+		printf("AVB not initialized, run 'avb init' first\n");
+		return CMD_RET_FAILURE;
+	}
+
+	if (argc != 1) {
+		printf("--%s(-1)\n", __func__);
+		return CMD_RET_USAGE;
+	}
+
+	if (avb_ops->read_is_device_unlocked(avb_ops, &unlock) ==
+	    AVB_IO_RESULT_OK) {
+		printf("Unlocked = %d\n", unlock);
+		return CMD_RET_SUCCESS;
+	}
+
+	return CMD_RET_FAILURE;
+}
+
+static cmd_tbl_t cmd_avb[] = {
+	U_BOOT_CMD_MKENT(init, 2, 0, do_avb_init, "", ""),
+	U_BOOT_CMD_MKENT(read_rb, 2, 0, do_avb_read_rb, "", ""),
+	U_BOOT_CMD_MKENT(write_rb, 3, 0, do_avb_write_rb, "", ""),
+	U_BOOT_CMD_MKENT(is_unlocked, 1, 0, do_avb_is_unlocked, "", ""),
+	U_BOOT_CMD_MKENT(get_uuid, 2, 0, do_avb_get_uuid, "", ""),
+	U_BOOT_CMD_MKENT(read_part, 5, 0, do_avb_read_part, "", ""),
+	U_BOOT_CMD_MKENT(read_part_hex, 4, 0, do_avb_read_part_hex, "", ""),
+	U_BOOT_CMD_MKENT(write_part, 5, 0, do_avb_write_part, "", ""),
+	U_BOOT_CMD_MKENT(verify, 1, 0, do_avb_verify_part, "", ""),
+};
+
+static int do_avb(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	cmd_tbl_t *cp;
+
+	cp = find_cmd_tbl(argv[1], cmd_avb, ARRAY_SIZE(cmd_avb));
+
+	argc--;
+	argv++;
+
+	if (!cp || argc > cp->maxargs)
+		return CMD_RET_USAGE;
+
+	if (flag == CMD_FLAG_REPEAT)
+		return CMD_RET_FAILURE;
+
+	return cp->cmd(cmdtp, flag, argc, argv);
+}
+
+U_BOOT_CMD(
+	avb, 29, 0, do_avb,
+	"Provides commands for testing Android Verified Boot 2.0 functionality",
+	"init <dev> - initialize avb2 for <dev>\n"
+	"avb read_rb <num> - read rollback index at location <num>\n"
+	"avb write_rb <num> <rb> - write rollback index <rb> to <num>\n"
+	"avb is_unlocked - returns unlock status of the device\n"
+	"avb get_uuid <partname> - read and print uuid of partition <part>\n"
+	"avb read_part <partname> <offset> <num> <addr> - read <num> bytes from\n"
+	"    partition <partname> to buffer <addr>\n"
+	"avb read_part_hex <partname> <offset> <num> - read <num> bytes from\n"
+	"    partition <partname> and print to stdout\n"
+	"avb write_part <partname> <offset> <num> <addr> - write <num> bytes to\n"
+	"    <partname> by <offset> using data from <addr>\n"
+	"avb verify - run verification process using hash data\n"
+	"    from vbmeta structure\n"
+	);