[PATCH v2 1/2] efi_firmware: set EFI capsule dfu_alt_info env explicitly

[Michal Simek]

On 2/6/25 16:47, Jonathan Humphreys wrote:
> The current implementation of EFI capsule update uses set_dfu_alt_info() to
> set the dfu_alt_info environment variable with the settings it requires.
> However, set_dfu_alt_info() is doing this for all DFU operations, even
> those unrelated to capsule update.
> 
> Thus other uses of DFU, such as DFU boot which sets its own value for the
> dfu_alt_info environment variable, will have that setting overwritten with
> the capsule update setting. Similarly, any user defined value for the
> dfu_alt_info environment variable would get overwritten when any DFU
> operation was performed, including simply performing a "dfu 0 list"
> command.
> 
> The solution is stop using the set_dfu_alt_info() mechanism to set the
> dfu_alt_info environment variable and instead explicitly set it to the
> capsule update's setting just before performing the capsule update's DFU
> operation, and then restore the environment variable back to its original
> value.
> 
> This patch implements the explicit setting and restoring of the
> dfu_alt_info environment variable as part of the EFI capsule update
> operation.
> 
> The fix is fully implemented in a subsequent patch that removes the capsule
> update dfu_alt_info support in set_dfu_alt_info().
> 
> Signed-off-by: Jonathan Humphreys <j-humphreys at ti.com>
> ---
>   lib/efi_loader/efi_firmware.c | 39 ++++++++++++++++++++++++++++++++---
>   1 file changed, 36 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
> index 5a754c9cd03..1a1cf3b55e1 100644
> --- a/lib/efi_loader/efi_firmware.c
> +++ b/lib/efi_loader/efi_firmware.c
> @@ -649,8 +649,10 @@ efi_status_t EFIAPI efi_firmware_fit_set_image(
>   	efi_status_t (*progress)(efi_uintn_t completion),
>   	u16 **abort_reason)
>   {
> +	int ret;
>   	efi_status_t status;
>   	struct fmp_state state = { 0 };
> +	char *orig_dfu_env;
>   
>   	EFI_ENTRY("%p %d %p %zu %p %p %p\n", this, image_index, image,
>   		  image_size, vendor_code, progress, abort_reason);
> @@ -663,7 +665,22 @@ efi_status_t EFIAPI efi_firmware_fit_set_image(
>   	if (status != EFI_SUCCESS)
>   		return EFI_EXIT(status);
>   
> -	if (fit_update(image))
> +	orig_dfu_env = strdup(env_get("dfu_alt_info"));
> +	if (env_set("dfu_alt_info", update_info.dfu_string)) {

This pretty much breaks all xilinx platforms because we actually are not 
configuring dfu_string.

I have sent RFC. If you can squash it to your patch that would be the best.
Pretty much the part of it should be in 1/2 and the part in 2/2.

M