The FMP Payload Header which EDK2 capsule generation scripts insert contains lowest supported version. This commit reads the lowest supported version stored in the "FmpStateXXXX" EFI non-volatile variable, then check if the firmware version of ongoing capsule is equal or greater than the lowest supported version.
Signed-off-by: Masahisa Kojima masahisa.kojima@linaro.org --- Changes in v2: - add error message when the firmware version is lower than lowest supported version
lib/efi_loader/efi_firmware.c | 45 ++++++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-)
diff --git a/lib/efi_loader/efi_firmware.c b/lib/efi_loader/efi_firmware.c index ead20fa914..fc6babfc34 100644 --- a/lib/efi_loader/efi_firmware.c +++ b/lib/efi_loader/efi_firmware.c @@ -368,6 +368,34 @@ void efi_firmware_parse_payload_header(const void **p_image, *p_image_size = image_size; }
+/** + * efi_firmware_get_lowest_supported_version - get the lowest supported version + * @image_index: image_index + * + * Get the lowest supported version from FmpStateXXXX variable. + * + * Return: lowest supported version, return 0 if reading FmpStateXXXX + * variable failed + */ +static +u32 efi_firmware_get_lowest_supported_version(u8 image_index) +{ + u16 varname[13]; /* u"FmpStateXXXX" */ + efi_status_t ret; + efi_uintn_t size; + struct fmp_state var_state = { 0 }; + + efi_create_indexed_name(varname, sizeof(varname), "FmpState", + image_index); + size = sizeof(var_state); + ret = efi_get_variable_int(varname, &efi_guid_fmp_state, NULL, &size, + &var_state, NULL); + if (ret != EFI_SUCCESS) + return 0; + + return var_state.lowest_supported_version; +} + /** * efi_firmware_verify_image - verify image * @p_image: Pointer to new image @@ -375,7 +403,8 @@ void efi_firmware_parse_payload_header(const void **p_image, * @image_index Image index * @state Pointer to fmp state * - * Verify the capsule file + * Verify the capsule authentication and check if the fw_version + * is equal or greater than the lowest supported version. * * Return: status code */ @@ -386,10 +415,24 @@ efi_status_t efi_firmware_verify_image(const void **p_image, struct fmp_state *state) { efi_status_t ret; + u32 lowest_supported_version;
ret = efi_firmware_capsule_authenticate(p_image, p_image_size, state); efi_firmware_parse_payload_header(p_image, p_image_size, state);
+ /* check lowest_supported_version if capsule authentication passes */ + if (ret == EFI_SUCCESS) { + lowest_supported_version = + efi_firmware_get_lowest_supported_version(image_index); + if (lowest_supported_version > state->fw_version) { + printf("fw_version(%u) is too low(expected >%u). Aborting update\n", + state->fw_version, lowest_supported_version); + state->last_attempt_status = + LAST_ATTEMPT_STATUS_ERROR_INCORRECT_VERSION; + ret = EFI_INVALID_PARAMETER; + } + } + return ret; }