Hi Jonathan,
On Mon, 3 Feb 2025 at 23:54, Jonathan Humphreys <j-humphr...@ti.com> 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-humphr...@ti.com>
> ---
> lib/efi_loader/efi_firmware.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c
> index 5a754c9cd03..d8b6d34ccab 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);
> @@ -663,9 +665,22 @@ efi_status_t EFIAPI efi_firmware_fit_set_image(
> if (status != EFI_SUCCESS)
> return EFI_EXIT(status);
>
> + orig_dfu_env = env_get("dfu_alt_info");
I don't think this will work. env_get returns a pointer to the data
which is going to change after the env_set
IOW this piece
env_set("dfu_alt_info", "test1");
orig_dfu_env = env_get("dfu_alt_info");
printf("now %s\n", orig_dfu_env); -> will print test1
env_set("dfu_alt_info", "test2");
dfu_env = env_get("dfu_alt_info");
printf("Orig %s now %s\n", orig_dfu_env, lala); -> will print
test2 test2
You have to copy the value of the pointer to an allocated piece of
memory to restore it
Thanks
/Ilias
> + ret = env_set("dfu_alt_info", update_info.dfu_string);
> + if (ret) {
> + pr_err("unable to set env variable \"dfu_alt_info\"!\n");
> + return -EINVAL;
> + }
> +
> if (fit_update(image))
> return EFI_EXIT(EFI_DEVICE_ERROR);
>
> + ret = env_set("dfu_alt_info", orig_dfu_env);
> + if (ret) {
> + pr_err("unable to set env variable \"dfu_alt_info\"!\n");
> + return -EINVAL;
> + }
> +
> efi_firmware_set_fmp_state_var(&state, image_index);
>
> return EFI_EXIT(EFI_SUCCESS);
> @@ -717,6 +732,7 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
> u8 dfu_alt_num;
> 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);
> @@ -747,10 +763,23 @@ efi_status_t EFIAPI efi_firmware_raw_set_image(
> }
> }
>
> + orig_dfu_env = env_get("dfu_alt_info");
> + ret = env_set("dfu_alt_info", update_info.dfu_string);
> + if (ret) {
> + pr_err("unable to set env variable \"dfu_alt_info\"!\n");
> + return -EINVAL;
> + }
> +
> if (dfu_write_by_alt(dfu_alt_num, (void *)image, image_size,
> NULL, NULL))
> return EFI_EXIT(EFI_DEVICE_ERROR);
>
> + ret = env_set("dfu_alt_info", orig_dfu_env);
> + if (ret) {
> + pr_err("unable to set env variable \"dfu_alt_info\"!\n");
> + return -EINVAL;
> + }
> +
> efi_firmware_set_fmp_state_var(&state, image_index);
>
> return EFI_EXIT(EFI_SUCCESS);
> --
> 2.34.1
>
