[PATCH v2] efi_loader: update SetVariable attribute check
Heinrich Schuchardt
xypron.glpk at gmx.de
Wed Feb 15 09:49:35 CET 2023
On 2/15/23 03:29, Masahisa Kojima wrote:
> UEFI specification v2.10 says that
> EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS is deprecated and
> EFI_UNSUPPORTED should be returned in SetVariable variable service.
> Current implementation returns EFI_INVALID_PARAMETER,
> let's fix the return value.
>
> Together with above change, this commit also updates the SetVariable
> attribute check to be aligned with the EDK2 reference implementation.
>
> Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
> ---
> Changes in v2:
> - fix coding style
> - HR must be set with NV
>
> lib/efi_loader/efi_variable.c | 33 ++++++++++++++++++++++++++-------
> 1 file changed, 26 insertions(+), 7 deletions(-)
>
> diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
> index 4c85cfa607..b12e79d658 100644
> --- a/lib/efi_loader/efi_variable.c
> +++ b/lib/efi_loader/efi_variable.c
> @@ -230,9 +230,31 @@ efi_status_t efi_set_variable_int(const u16 *variable_name,
> u64 time = 0;
> enum efi_auth_var_type var_type;
>
> - if (!variable_name || !*variable_name || !vendor ||
> - ((attributes & EFI_VARIABLE_RUNTIME_ACCESS) &&
> - !(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)))
> + if (!variable_name || !*variable_name || !vendor)
> + return EFI_INVALID_PARAMETER;
> +
> + if (data_size && !data)
> + return EFI_INVALID_PARAMETER;
> +
> + /* EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS is deprecated */
> + if (attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS ||
> + (!(attributes & EFI_VARIABLE_MASK)))
UEFI Spec 2.10, p. 215: "Setting a data variable with no access
attributes causes it to be deleted."
We don't want to make deletion unsupported.
Best regards
Heinrich
> + return EFI_UNSUPPORTED;
> +
> + /* Make sure if runtime bit is set, boot service bit is set also */
> + if ((attributes &
> + (EFI_VARIABLE_RUNTIME_ACCESS | EFI_VARIABLE_BOOTSERVICE_ACCESS)) ==
> + EFI_VARIABLE_RUNTIME_ACCESS)
> + return EFI_INVALID_PARAMETER;
> +
> + /* only EFI_VARIABLE_NON_VOLATILE attribute is invalid */
> + if ((attributes & EFI_VARIABLE_MASK) == EFI_VARIABLE_NON_VOLATILE)
> + return EFI_INVALID_PARAMETER;
> +
> + /* Make sure HR is set with NV */
> + if ((attributes &
> + (EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_HARDWARE_ERROR_RECORD)) ==
> + EFI_VARIABLE_HARDWARE_ERROR_RECORD)
> return EFI_INVALID_PARAMETER;
>
> /* check if a variable exists */
> @@ -281,8 +303,6 @@ efi_status_t efi_set_variable_int(const u16 *variable_name,
>
> /* authenticate a variable */
> if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) {
> - if (attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS)
> - return EFI_INVALID_PARAMETER;
> if (attributes &
> EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
> u32 env_attr;
> @@ -300,8 +320,7 @@ efi_status_t efi_set_variable_int(const u16 *variable_name,
> }
> } else {
> if (attributes &
> - (EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS |
> - EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
> + EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
> EFI_PRINT("Secure boot is not configured\n");
> return EFI_INVALID_PARAMETER;
> }
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