From 584a2ada6e5e7752ad1af2fd54fa8d424a4da8d6 Mon Sep 17 00:00:00 2001 From: Masahisa Kojima Date: Tue, 2 Apr 2024 18:09:50 +0900 Subject: [PATCH] efi_loader: fix append write behavior to non-existent variable 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 Reviewed-by: Ilias Apalodimas Tested-by: Ilias Apalodimas --- lib/efi_loader/efi_variable.c | 26 +++++++++--- lib/efi_selftest/efi_selftest_variables.c | 48 ++++++++++++++++++++++- 2 files changed, 66 insertions(+), 8 deletions(-) diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c index 40f7a0fb10..d1db7ade0a 100644 --- a/lib/efi_loader/efi_variable.c +++ b/lib/efi_loader/efi_variable.c @@ -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) diff --git a/lib/efi_selftest/efi_selftest_variables.c b/lib/efi_selftest/efi_selftest_variables.c index c7a3fdbaa6..39ad03a090 100644 --- a/lib/efi_selftest/efi_selftest_variables.c +++ b/lib/efi_selftest/efi_selftest_variables.c @@ -131,13 +131,57 @@ static int execute(void) (unsigned int)len); if (memcmp(data, v, len)) efi_st_todo("GetVariable returned wrong value\n"); - /* Append variable 2 */ + + /* Append variable 2, write to non-existent variable with datasize=0 */ + ret = runtime->set_variable(u"efi_none", &guid_vendor1, + EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_APPEND_WRITE, + 0, v); + if (ret != EFI_SUCCESS) { + efi_st_error( + "SetVariable(APPEND_WRITE) with size 0 to non-existent variable returns wrong code\n"); + return EFI_ST_FAILURE; + } + len = EFI_ST_MAX_DATA_SIZE; + ret = runtime->get_variable(u"efi_none", &guid_vendor1, + &attr, &len, data); + if (ret != EFI_NOT_FOUND) { + efi_st_error("Variable must not be created\n"); + return EFI_ST_FAILURE; + } + /* Append variable 2, write to non-existent variable with valid data size*/ ret = runtime->set_variable(u"efi_none", &guid_vendor1, EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_APPEND_WRITE, 15, v); + if (ret != EFI_SUCCESS) { + efi_st_error("SetVariable(APPEND_WRITE) with valid size and data to non-existent variable must be succcessful\n"); + return EFI_ST_FAILURE; + } + len = EFI_ST_MAX_DATA_SIZE; + ret = runtime->get_variable(u"efi_none", &guid_vendor1, + &attr, &len, data); + if (ret != EFI_SUCCESS) { + efi_st_error("GetVariable failed\n"); + return EFI_ST_FAILURE; + } + if (len != 15) + efi_st_todo("GetVariable returned wrong length %u\n", + (unsigned int)len); + if (memcmp(data, v, len)) + efi_st_todo("GetVariable returned wrong value\n"); + /* Delete variable efi_none */ + ret = runtime->set_variable(u"efi_none", &guid_vendor1, + 0, 0, NULL); + if (ret != EFI_SUCCESS) { + efi_st_error("SetVariable failed\n"); + return EFI_ST_FAILURE; + } + len = EFI_ST_MAX_DATA_SIZE; + ret = runtime->get_variable(u"efi_none", &guid_vendor1, + &attr, &len, data); if (ret != EFI_NOT_FOUND) { - efi_st_error("SetVariable(APPEND_WRITE) with size 0 to non-existent variable returns wrong code\n"); + efi_st_error("Variable was not deleted\n"); return EFI_ST_FAILURE; } /* Enumerate variables */ -- 2.39.5