On 3/27/19 5:40 AM, AKASHI Takahiro wrote:
> Add CONFIG_CMD_STANDALONE_EFIBOOTMGR.
> With this patch, EFI boot manager can be kicked in by a standalone
> command, efibootmgr.
I miss your comment form 0/11 here:
* When we will support "secure boot" in the future, EFI Boot Manager
is expected to be invoked as a standalone command without any
arguments to mitigate security surfaces.
Simply requiring that environment variable $fdtaddr, which is under user
control, is used for loading the device tree does not offer any security
at all.
For secure boot I would expect that the device tree has to be part of a
signed binary and that that signature is checked.
If the user passes in a device tree that should be okay if it has the
required signature.
>
> Signed-off-by: AKASHI Takahiro <takahiro.aka...@linaro.org>
> ---
> cmd/Kconfig | 8 ++++++++
> cmd/bootefi.c | 35 +++++++++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+)
>
> diff --git a/cmd/Kconfig b/cmd/Kconfig
> index 4bcc5c45579d..aa27b21956b3 100644
> --- a/cmd/Kconfig
> +++ b/cmd/Kconfig
> @@ -224,6 +224,14 @@ config CMD_BOOTEFI
> help
> Boot an EFI image from memory.
>
> +config CMD_STANDALONE_EFIBOOTMGR
> + bool "Enable EFI Boot Manager as a standalone command"
> + depends on CMD_BOOTEFI
> + default n
> + help
> + With this option enabled, EFI Boot Manager can be invoked
> + as a standalone command.
> +
> config CMD_BOOTEFI_HELLO_COMPILE
> bool "Compile a standard EFI hello world binary for testing"
> depends on CMD_BOOTEFI && !CPU_V7M && !SANDBOX
> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
> index 17dccd718008..2a2ff4034831 100644
> --- a/cmd/bootefi.c
> +++ b/cmd/bootefi.c
> @@ -635,3 +635,38 @@ void efi_set_bootdev(const char *dev, const char *devnr,
> const char *path)
> bootefi_image_path = NULL;
> }
> }
> +
> +#ifdef CONFIG_CMD_STANDALONE_EFIBOOTMGR
> +static int do_efibootmgr_cmd(cmd_tbl_t *cmdtp, int flag, int argc,
> + char * const argv[])
> +{
> + char *fdt_opt;
> + int ret;
> +
> + if (argc != 1)
> + return CMD_RET_USAGE;
It is unclear why you do not allow the user to pass the location of the
device tree as a parameter.
> +
> + fdt_opt = env_get("fdtaddr");
You are looking at some environment variable $fdtaddr while most boards
use $fdt_addr_r as preferred address to load the device tree.
Best regards
Heinrich
> + if (!fdt_opt)> + fdt_opt = env_get("fdtcontroladdr");
> +
> + ret = do_efibootmgr(fdt_opt);
> +
> + free(fdt_opt);
> +
> + return ret;
> +}
> +
> +#ifdef CONFIG_SYS_LONGHELP
> +static char efibootmgr_help_text[] =
> + "(no arguments)\n"
> + " - Launch EFI boot manager and execute EFI application\n"
> + " based on BootNext and BootOrder variables\n";
> +#endif
> +
> +U_BOOT_CMD(
> + efibootmgr, 1, 0, do_efibootmgr_cmd,
> + "Launch EFI boot manager",
> + efibootmgr_help_text
> +);
> +#endif /* CONFIG_CMD_STANDALONE_EFIBOOTMGR */
>
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