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efi_loader: fix append write behavior to non-existent variable

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Current "variables" efi_selftest result is inconsistent
between the U-Boot file storage and the tee-based StandaloneMM
RPMB secure storage.

U-Boot file storage implementation does not accept SetVariale
call to non-existent variable with EFI_VARIABLE_APPEND_WRITE,
it return EFI_NOT_FOUND.
However it is accepted and new variable is created in EDK II
StandaloneMM implementation if valid data and size are specified.
If data size is 0, EFI_SUCCESS is returned.

Since UEFI specification does not clearly describe the behavior
of the append write to non-existent variable, let's update
the U-Boot file storage implementation to get aligned with
the EDK II reference implementation.

Signed-off-by: Masahisa Kojima <kojima.masahisa@socionext.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
This commit is contained in:
Masahisa Kojima 2024-04-02 18:09:50 +09:00 • committed by Heinrich Schuchardt
parent 73d533b244
commit 584a2ada6e
2 changed files with 66 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

26
lib/efi_loader/efi_variable.c
View file

@ -282,11 +282,21 @@ efi_status_t efi_set_variable_int(const u16 *variable_name,
}
time = var->time;
} else {
if (delete || append)
/*
* Trying to delete or to update a non-existent
* variable.
*/
/*
* UEFI specification does not clearly describe the expected
* behavior of append write with data size 0, we follow
* the EDK II reference implementation.
*/
if (append && !data_size)
return EFI_SUCCESS;
/*
* EFI_VARIABLE_APPEND_WRITE to non-existent variable is accepted
* and new variable is created in EDK II reference implementation.
* We follow it and only check the deletion here.
*/
if (delete)
/* Trying to delete a non-existent variable. */
return EFI_NOT_FOUND;
}
@ -329,7 +339,11 @@ efi_status_t efi_set_variable_int(const u16 *variable_name,
/* EFI_NOT_FOUND has been handled before */
attributes = var->attr;
ret = EFI_SUCCESS;
} else if (append) {
} else if (append && var) {
/*
* data is appended if EFI_VARIABLE_APPEND_WRITE is set and
* variable exists.
*/
u16 *old_data = var->name;
for (; *old_data; ++old_data)