[PATCH] cmd: bootefi: restore ability to boot arbitrary blob

[Heinrich Schuchardt]

On 4/6/22 07:04, kevans at FreeBSD.org wrote:
> From: Kyle Evans <kevans at FreeBSD.org>
>
> Up until commit 5f59518a7b1ae ("efi_loader: setting boot device"), we
> could boot an arbitrary blob with bootefi.  Indeed, efi_run_image() even
> has a special case for missing device paths indicating a payload that
> was directly loaded via JTAG, for example.
>
> Restore the ability to inject a UEFI payload into memory and `bootefi`
> it.  If the address passed isn't the last PE-COFF loaded, then we'll
> wipe out the pre-existing DP/Image information and let efi_run_image()
> synthesize a memory device path.
>
> An image size is required if we're booting an arbitrary payload, and
> the FDT argument has been changed to accept `-`.  The size could be
> deduced from the image header, but it's required anyways as an explicit
> acknowledgment that one's trying to boot an arbitrary payload rather
> than accidentally using the wrong address in the single-addr form.
>
> Signed-off-by: Kyle Evans <kevans at FreeBSD.org>

I have tested at follows:

host bind 0 ../sandbox.img
load host 0:1 $kernel_addr_r helloworld.efi
bootefi $fdt_add_r

Expected result is a message
No UEFI binary known at 0xc00000

With your patch the message is not shown. Instead the help text for
bootefi is displayed.

> ---
>
>   cmd/bootefi.c | 36 ++++++++++++++++++++++++++++--------
>   1 file changed, 28 insertions(+), 8 deletions(-)
>
> diff --git a/cmd/bootefi.c b/cmd/bootefi.c
> index 53d9f0e0dc..1dac74781e 100644
> --- a/cmd/bootefi.c
> +++ b/cmd/bootefi.c
> @@ -425,7 +425,7 @@ static int do_efibootmgr(void)
>    * @image_opt:	string of image start address
>    * Return:	status code
>    */
> -static int do_bootefi_image(const char *image_opt)
> +static int do_bootefi_image(const char *image_opt, const char *size_opt)
>   {
>   	void *image_buf;
>   	unsigned long addr, size;
> @@ -444,13 +444,29 @@ static int do_bootefi_image(const char *image_opt)
>   		if (!addr)
>   			return CMD_RET_USAGE;
>
> +		size = 0;
> +		if (size_opt) {
> +			size = strtoul(size_opt, NULL, 16);
> +			/* Check that a numeric value was passed */
> +			if (!size)
> +				return CMD_RET_USAGE;
> +		}
> +
>   		image_buf = map_sysmem(addr, 0);
>
>   		if (image_buf != image_addr) {
> -			log_err("No UEFI binary known at %s\n", image_opt);
> -			return CMD_RET_FAILURE;
> +			/* Fake device path -- we must have a size. */
> +
> +			if (image_addr)
> +				efi_clear_bootdev();
> +
> +			if (size == 0)
> +				return CMD_RET_USAGE;
> +		} else {
> +			if (size != 0)
> +				return CMD_RET_USAGE;
> +			size = image_size;
>   		}
> -		size = image_size;
>   	}
>   	ret = efi_run_image(image_buf, size);
>
> @@ -654,7 +670,7 @@ static int do_bootefi(struct cmd_tbl *cmdtp, int flag, int argc,
>   		return CMD_RET_FAILURE;
>   	}
>
> -	if (argc > 2) {
> +	if (argc > 2 && strcmp(argv[2], "-") != 0) {
>   		uintptr_t fdt_addr;
>
>   		fdt_addr = hextoul(argv[2], NULL);
> @@ -677,15 +693,19 @@ static int do_bootefi(struct cmd_tbl *cmdtp, int flag, int argc,
>   		return do_efi_selftest();
>   #endif
>
> -	return do_bootefi_image(argv[1]);
> +	return do_bootefi_image(argv[1], argc > 3 ? argv[3] : NULL);
>   }
>
>   #ifdef CONFIG_SYS_LONGHELP
>   static char bootefi_help_text[] =
> -	"<image address> [fdt address]\n"
> +	"<image address> [fdt address [image size]]\n"
>   	"  - boot EFI payload stored at address <image address>.\n"
>   	"    If specified, the device tree located at <fdt address> gets\n"
>   	"    exposed as EFI configuration table.\n"
> +	"    The image size is required if this is not a preloaded image, but\n"
> +	"    it must be omitted if the image was preloaded.\n"

Why must the image size be omitted?

I expect the following to work fine:

load host 0:1 $kernel_addr_r foo.efi
bootefi $kernel_addr_r - $filesize

Best regards

Heinrich

> +	"    The <fdt address> parameter accepts '-' to indicate FDT already\n"
> +	"    installed or pre-specified in fdt_addr or fdtcontroladdr.\n"
>   #ifdef CONFIG_CMD_BOOTEFI_HELLO
>   	"bootefi hello\n"
>   	"  - boot a sample Hello World application stored within U-Boot\n"
> @@ -707,7 +727,7 @@ static char bootefi_help_text[] =
>   #endif
>
>   U_BOOT_CMD(
> -	bootefi, 3, 0, do_bootefi,
> +	bootefi, 4, 0, do_bootefi,
>   	"Boots an EFI payload from memory",
>   	bootefi_help_text
>   );