Currently, fastboot protocol in U-Boot has no opportunity to execute vendor custom code with verifed boot. This patch introduce new fastboot subcommand fastboot oem board:<cmd>, which allow to run custom oem_board function.

Default implementation is __weak. Vendor must redefine it in board/ folder with his own logic.

For example, some vendors have their custom nand/emmc partition flashing or erasing. Here some typical command for such use cases:

- flashing:

$ fastboot stage bootloader.img $ fastboot oem board:write_bootloader

- erasing:

$ fastboot oem board:erase_env

Signed-off-by: Alexey Romanov avromanov@salutedevices.com Reviewed-by: Mattijs Korpershoek mkorpershoek@baylibre.com Reviewed-by: Quentin Schulz quentin.schulz@theobroma-systems.com --- doc/android/fastboot.rst | 18 ++++++++++++++++++ drivers/fastboot/Kconfig | 7 +++++++ drivers/fastboot/fb_command.c | 30 ++++++++++++++++++++++++++++++ include/fastboot.h | 1 + 4 files changed, 56 insertions(+)

diff --git a/doc/android/fastboot.rst b/doc/android/fastboot.rst index 05d8f77759..6f92cd28eb 100644 --- a/doc/android/fastboot.rst +++ b/doc/android/fastboot.rst @@ -30,6 +30,7 @@ The following OEM commands are supported (if enabled): - ``oem bootbus`` - this executes ``mmc bootbus %x %s`` to configure eMMC - ``oem run`` - this executes an arbitrary U-Boot command - ``oem console`` - this dumps U-Boot console record buffer +- ``oem board`` - this executes a custom board function which is defined by the vendor

Support for both eMMC and NAND devices is included.

@@ -246,6 +247,23 @@ including multiple commands (using e.g. ``;`` or ``&&``) and control structures (``if``, ``while``, etc.). The exit code of ``fastboot`` will reflect the exit code of the command you ran.

+Running Custom Vendor Code +^^^^^^^^^^^^^^^^^^^^^^^^^^ + +U-Boot allows you to execute custom fastboot logic, which can be defined +in board/ files. It can still be used for production devices with verified +boot, because the vendor defines logic at compile time by implementing +fastboot_oem_board() function. The attacker will not be able to execute +custom commands / code. For example, this can be useful for custom flashing +or erasing protocols:: + + $ fastboot stage bootloader.img + $ fastboot oem board:write_bootloader + +In this case, ``cmd_parameter`` argument of the function ``fastboot_oem_board()`` +will contain string "write_bootloader" and ``data`` argument is a pointer to +fastboot input buffer, which contains the contents of bootloader.img file. + References ----------

diff --git a/drivers/fastboot/Kconfig b/drivers/fastboot/Kconfig index d59e5b5ece..2ad74baaf2 100644 --- a/drivers/fastboot/Kconfig +++ b/drivers/fastboot/Kconfig @@ -249,6 +249,13 @@ config FASTBOOT_CMD_OEM_CONSOLE Add support for the "oem console" command to input and read console record buffer.

+config FASTBOOT_OEM_BOARD + bool "Enable the 'oem board' command" + help + This extends the fastboot protocol with an "oem board" command. This + command allows running vendor custom code defined in board/ files. + Otherwise, it will do nothing and send fastboot fail. + endif # FASTBOOT

endmenu diff --git a/drivers/fastboot/fb_command.c b/drivers/fastboot/fb_command.c index f95f4e4ae1..01443c5d39 100644 --- a/drivers/fastboot/fb_command.c +++ b/drivers/fastboot/fb_command.c @@ -42,6 +42,7 @@ static void oem_format(char *, char *); static void oem_partconf(char *, char *); static void oem_bootbus(char *, char *); static void oem_console(char *, char *); +static void oem_board(char *, char *); static void run_ucmd(char *, char *); static void run_acmd(char *, char *);

@@ -113,6 +114,10 @@ static const struct { .command = "oem console", .dispatch = CONFIG_IS_ENABLED(FASTBOOT_CMD_OEM_CONSOLE, (oem_console), (NULL)) }, + [FASTBOOT_COMMAND_OEM_BOARD] = { + .command = "oem board", + .dispatch = CONFIG_IS_ENABLED(FASTBOOT_OEM_BOARD, (oem_board), (NULL)) + }, [FASTBOOT_COMMAND_UCMD] = { .command = "UCmd", .dispatch = CONFIG_IS_ENABLED(FASTBOOT_UUU_SUPPORT, (run_ucmd), (NULL)) @@ -542,3 +547,28 @@ static void __maybe_unused oem_console(char *cmd_parameter, char *response) else fastboot_response(FASTBOOT_MULTIRESPONSE_START, response, NULL); } + +/** + * fastboot_oem_board() - Execute the OEM board command. This is default + * weak implementation, which may be overwritten in board/ files. + * + * @cmd_parameter: Pointer to command parameter + * @data: Pointer to fastboot input buffer + * @size: Size of the fastboot input buffer + * @response: Pointer to fastboot response buffer + */ +void __weak fastboot_oem_board(char *cmd_parameter, void *data, u32 size, char *response) +{ + fastboot_fail("oem board function not defined", response); +} + +/** + * oem_board() - Execute the OEM board command + * + * @cmd_parameter: Pointer to command parameter + * @response: Pointer to fastboot response buffer + */ +static void __maybe_unused oem_board(char *cmd_parameter, char *response) +{ + fastboot_oem_board(cmd_parameter, (void *)fastboot_buf_addr, image_size, response); +} diff --git a/include/fastboot.h b/include/fastboot.h index 1e7920eb91..2ca1b907a5 100644 --- a/include/fastboot.h +++ b/include/fastboot.h @@ -48,6 +48,7 @@ enum { FASTBOOT_COMMAND_OEM_BOOTBUS, FASTBOOT_COMMAND_OEM_RUN, FASTBOOT_COMMAND_OEM_CONSOLE, + FASTBOOT_COMMAND_OEM_BOARD, FASTBOOT_COMMAND_ACMD, FASTBOOT_COMMAND_UCMD, FASTBOOT_COMMAND_COUNT