[U-Boot] [PATCH 4/8] cmd: avb2.0: avb command for performing verification

[Sam Protsenko <semen.protsenko@linaro.org>]

On 25 April 2018 at 16:18, Igor Opaniuk <igor.opaniuk@linaro.org> wrote:
> 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  |  15 +++
>  cmd/Makefile |   3 +
>  cmd/avb.c    | 351 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 369 insertions(+)
>  create mode 100644 cmd/avb.c
>
> diff --git a/cmd/Kconfig b/cmd/Kconfig
> index bc1d2f3..96695ff 100644
> --- a/cmd/Kconfig
> +++ b/cmd/Kconfig
> @@ -1675,6 +1675,21 @@ 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_AB
> +       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
> diff --git a/cmd/Makefile b/cmd/Makefile
> index c4269ac..bbf6c2a 100644
> --- a/cmd/Makefile
> +++ b/cmd/Makefile
> @@ -151,6 +151,9 @@ 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
>
> diff --git a/cmd/avb.c b/cmd/avb.c
> new file mode 100644
> index 0000000..d040906
> --- /dev/null
> +++ b/cmd/avb.c
> @@ -0,0 +1,351 @@
> +
> +/*
> + * (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);

+ Simon Glass

AFAIU, to make it possible to run this command on "sandbox", you
should use map_sysmem() and friends.

> +
> +       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, &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"
> +       );
> --
> 2.7.4
>