[PATCH] disk: Use part_driver_lookup_type() to valid downloaded image
Ilias Apalodimas
ilias.apalodimas at linaro.org
Tue Aug 5 10:25:22 CEST 2025
Hi Javier
On Fri, 1 Aug 2025 at 00:35, Javier Tia <javier.tia at linaro.org> wrote:
>
> The part_driver_lookup_type() function was made public to be used in the
> EFI loader. This function is used to look up the partition type for a
> block device.
>
> This change allows the EFI loader to detect disk images by using the
> partition driver lookup. This replaces the previous method of checking
> the file extension, which was less optimal.
>
> The EFI loader generates a temporary block device from the downloaded
> image, employs the part_driver_lookup_type() function to verify the
> partition type, and checks if it corresponds to a valid ISO 9660, DOS
> MBR, or GPT EFI disk image, subsequently performing cleanup of the
> temporary device. If the downloaded file does not constitute a valid
> disk image, an error message will be logged, and the function will
> return EFI_UNSUPPORTED.
>
> Signed-off-by: Javier Tia <javier.tia at linaro.org>
> ---
> disk/part.c | 3 +-
> include/part.h | 18 +++++++++
> lib/efi_loader/efi_bootmgr.c | 76 +++++++++++++++++++++++++++++++-----
> 3 files changed, 87 insertions(+), 10 deletions(-)
>
> diff --git a/disk/part.c b/disk/part.c
> index 66e2b3a7219..adc24976624 100644
> --- a/disk/part.c
> +++ b/disk/part.c
> @@ -63,7 +63,7 @@ static struct part_driver *part_driver_get_type(int part_type)
> * @dev_desc: Device descriptor
> * Return: Driver found, or NULL if none
> */
> -static struct part_driver *part_driver_lookup_type(struct blk_desc *desc)
> +struct part_driver *part_driver_lookup_type(struct blk_desc *desc)
> {
> struct part_driver *drv =
> ll_entry_start(struct part_driver, part_driver);
> @@ -855,3 +855,4 @@ int part_get_bootable(struct blk_desc *desc)
>
> return 0;
> }
> +
> diff --git a/include/part.h b/include/part.h
> index b772fb34c8a..3fc3186f4c4 100644
> --- a/include/part.h
> +++ b/include/part.h
> @@ -727,6 +727,24 @@ int part_get_type_by_name(const char *name);
> */
> int part_get_bootable(struct blk_desc *desc);
>
> +/**
> + * part_driver_lookup_type() - Look up the partition driver for a blk device
> + *
> + * If @desc->part_type is PART_TYPE_UNKNOWN, this checks each partition driver
> + * against the blk device to see if there is a valid partition table acceptable
> + * to that driver.
> + *
> + * If @desc->part_type is already set, it just returns the driver for that
> + * type, without testing if the driver can find a valid partition on the
> + * descriptor.
> + *
> + * On success it updates @desc->part_type if set to PART_TYPE_UNKNOWN on entry
> + *
> + * @desc: Device descriptor
> + * Return: Driver found, or NULL if none
> + */
> +struct part_driver *part_driver_lookup_type(struct blk_desc *desc);
> +
> #else
> static inline int part_driver_get_count(void)
> { return 0; }
> diff --git a/lib/efi_loader/efi_bootmgr.c b/lib/efi_loader/efi_bootmgr.c
> index 662993fb809..f6729a40462 100644
> --- a/lib/efi_loader/efi_bootmgr.c
> +++ b/lib/efi_loader/efi_bootmgr.c
> @@ -17,6 +17,7 @@
> #include <log.h>
> #include <malloc.h>
> #include <net.h>
> +#include <part.h>
> #include <efi_loader.h>
> #include <efi_variable.h>
> #include <asm/unaligned.h>
> @@ -407,7 +408,7 @@ static efi_status_t efi_bootmgr_release_uridp(struct uridp_context *ctx)
> if (!ctx)
> return ret;
>
> - /* cleanup for iso or img image */
> + /* cleanup for disk image */
> if (ctx->ramdisk_blk_dev) {
> ret = efi_add_memory_map(ctx->image_addr, ctx->image_size,
> EFI_CONVENTIONAL_MEMORY);
> @@ -452,6 +453,17 @@ static void EFIAPI efi_bootmgr_http_return(struct efi_event *event,
> EFI_EXIT(ret);
> }
>
> +/**
> + * cleanup_temp_blkdev() - Clean up temporary block device
> + *
> + * @temp_bdev: temporary block device to clean up
> + */
> +static void cleanup_temp_blkdev(struct udevice *temp_bdev)
> +{
> + if (blkmap_destroy(temp_bdev->parent))
> + log_err("Destroying temporary blkmap failed\n");
> +}
No need to add a new function for a call, just call blkmap_destroy() directly.
If you want to keep it as a separate function, just move the if
(temp_bdev) in here.
> +
> /**
> * try_load_from_uri_path() - Handle the URI device path
> *
> @@ -466,7 +478,6 @@ static efi_status_t try_load_from_uri_path(struct efi_device_path_uri *uridp,
> {
> char *s;
> int err;
> - int uri_len;
> efi_status_t ret;
> void *source_buffer;
> efi_uintn_t source_size;
> @@ -516,13 +527,55 @@ static efi_status_t try_load_from_uri_path(struct efi_device_path_uri *uridp,
> image_size = ALIGN(image_size, SZ_2M);
>
> /*
> - * If the file extension is ".iso" or ".img", mount it and try to load
> - * the default file.
> - * If the file is PE-COFF image, load the downloaded file.
> + * Check if the downloaded file is a disk image or PE-COFF image.
> + * Use partition driver lookup for disk image detection.
> */
> - uri_len = strlen(uridp->uri);
> - if (!strncmp(&uridp->uri[uri_len - 4], ".iso", 4) ||
> - !strncmp(&uridp->uri[uri_len - 4], ".img", 4)) {
> + struct udevice *temp_bdev;
> + struct part_driver *part_drv = NULL;
> +
> + /* Create temporary block device from the downloaded image for testing */
> + temp_bdev = mount_image(lo_label, image_addr, image_size);
> + if (!temp_bdev) {
> + log_debug("mount_image() failed, will attempt PE-COFF detection\n");
> + }
It's a single line in the if, drop the {}
> + if (temp_bdev) {
> + struct blk_desc *desc = dev_get_uclass_plat(temp_bdev);
> + if (!desc) {
> + /* Clean up temporary device when dev_get_uclass_plat() returns NULL */
> + cleanup_temp_blkdev(temp_bdev);
> + } else {
> + /* Use part_driver_lookup_type for comprehensive partition detection */
> + part_drv = part_driver_lookup_type(desc);
> +
> + /* Validate partition type */
> + if (part_drv) {
> + if (part_drv->part_type != PART_TYPE_DOS &&
> + part_drv->part_type != PART_TYPE_ISO &&
> + part_drv->part_type != PART_TYPE_EFI) {
Why does it have to be one of those partition types? The EFI spec does
not require the ESP to be a FAT.
> + log_err("Unsupported partition type 0x%02x for EFI boot. "
> + "Only MBR DOS, ISO, and EFI partition types are supported.\n",
> + part_drv->part_type);
> +
> + /* Clean up temporary device */
> + cleanup_temp_blkdev(temp_bdev);
> +
> + /* Set part_drv to NULL to fall through to PE-COFF detection */
> + part_drv = NULL;
> + }
> + }
> +
> + /*
> + * If it's a disk image with supported partition type,
> + * prepare_loaded_image will create the final block device
> + */
> + if (part_drv) {
> + /* Clean up temporary device, prepare_loaded_image will create a new one */
> + cleanup_temp_blkdev(temp_bdev);
> + }
> + }
> + }
> +
> + if (part_drv) {
> ret = prepare_loaded_image(lo_label, image_addr, image_size,
> &loaded_dp, &blk);
> if (ret != EFI_SUCCESS)
> @@ -545,7 +598,12 @@ static efi_status_t try_load_from_uri_path(struct efi_device_path_uri *uridp,
> source_buffer = (void *)image_addr;
> source_size = image_size;
> } else {
> - log_err("Error: file type is not supported\n");
> + /* Clean up temporary device if it was created but not a valid disk image */
> + if (temp_bdev) {
> + cleanup_temp_blkdev(temp_bdev);
> + }
> +
> + log_err("Error: disk image is not supported\n");
> ret = EFI_UNSUPPORTED;
> goto err;
> }
> --
> 2.50.1
>
Thanks
/Ilias
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