[PATCH] disk: efi_loader: Improve disk image detection in efi_bootmgr

[Javier Tia]

Hi Heinrich,

On Fri, Aug 8, 2025, at 12:50 AM, Heinrich Schuchardt wrote:
> On 05.08.25 18:21, Javier Tia wrote:
>> Refines the disk image detection mechanism in the EFI boot manager.
>> Instead of relying on file extensions, the updated code uses the
>> partition driver lookup function to determine if a downloaded file is a
>> valid disk image.
>> 
>> The change enhances the robustness of the boot manager by providing a
>> more accurate disk image detection. It also improves error handling by
>> adding a cleanup function for temporary block devices.
>> 
>> The partition driver lookup function is also made public to enable its
>> use in the EFI boot manager. The function documentation is updated
>> accordingly.
>> 
>> Signed-off-by: Javier Tia <javier.tia at linaro.org>
>> ---
>>   disk/part.c                  |  3 +-
>>   include/part.h               | 18 +++++++++++
>>   lib/efi_loader/efi_bootmgr.c | 59 ++++++++++++++++++++++++++++++------
>>   3 files changed, 70 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..7acb4f4e92b 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 +453,20 @@ 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 (!temp_bdev)
>> +		return;
>> +
>> +	if (blkmap_destroy(temp_bdev->parent))
>> +		log_err("Destroying temporary blkmap failed\n");
>> +}
>> +
>>   /**
>>    * try_load_from_uri_path() - Handle the URI device path
>>    *
>> @@ -466,7 +481,6 @@ 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 +530,37 @@ 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");
>> +	}
>> +	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);
>> +
>> +			/*
>> +			 * If it's a disk image with valid 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);
>
> Why wouldn't you remove the temporary disk if there is no partition driver?
>
> Why wouldn't we keep the temporary disk if it is usable instead of 
> creating a new one?

Thank you for the review. I have addressed your comments at 
https://lore.kernel.org/u-boot/20250808213627.649669-1-javier.tia@linaro.org/#r

Thanks.

> Best regards
>
> Heinrich
>
>> +		}
>> +	}
>> +
>> +	if (part_drv) {
>>   		ret = prepare_loaded_image(lo_label, image_addr, image_size,
>>   					   &loaded_dp, &blk);
>>   		if (ret != EFI_SUCCESS)
>> @@ -545,7 +583,10 @@ 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 */
>> +		cleanup_temp_blkdev(temp_bdev);
>> +
>> +		log_err("Error: disk image is not supported\n");
>>   		ret = EFI_UNSUPPORTED;
>>   		goto err;
>>   	}

-- 
» Javier Tia ✍