From cb7116030aff44f48f29bdc3bd7ed22f7ad74bb9 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Wed, 1 Jul 2020 15:32:47 +0200 Subject: [PATCH] efi_loader: time based authentication When overwriting an existing time base authenticated variable we should compare to the preceding time value and not to the start of the epoch. Signed-off-by: Heinrich Schuchardt --- lib/efi_loader/efi_variable.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c index f9a0efd427..4d49fd60dc 100644 --- a/lib/efi_loader/efi_variable.c +++ b/lib/efi_loader/efi_variable.c @@ -35,7 +35,8 @@ static u8 efi_vendor_keys; static efi_status_t efi_get_variable_common(u16 *variable_name, const efi_guid_t *vendor, u32 *attributes, - efi_uintn_t *data_size, void *data); + efi_uintn_t *data_size, void *data, + u64 *timep); static efi_status_t efi_set_variable_common(u16 *variable_name, const efi_guid_t *vendor, @@ -309,7 +310,7 @@ static efi_status_t efi_init_secure_state(void) size = 0; ret = efi_get_variable_common(L"PK", &efi_global_variable_guid, - NULL, &size, NULL); + NULL, &size, NULL, NULL); if (ret == EFI_BUFFER_TOO_SMALL) { if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) mode = EFI_MODE_USER; @@ -601,7 +602,8 @@ static efi_status_t efi_variable_authenticate(u16 *variable, static efi_status_t efi_get_variable_common(u16 *variable_name, const efi_guid_t *vendor, u32 *attributes, - efi_uintn_t *data_size, void *data) + efi_uintn_t *data_size, void *data, + u64 *timep) { char *native_name; efi_status_t ret; @@ -626,6 +628,9 @@ static efi_status_t efi_get_variable_common(u16 *variable_name, val = parse_attr(val, &attr, &time); + if (timep) + *timep = time; + in_size = *data_size; if ((s = prefix(val, "(blob)"))) { @@ -709,7 +714,7 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name, data_size, data); ret = efi_get_variable_common(variable_name, vendor, attributes, - data_size, data); + data_size, data, NULL); return EFI_EXIT(ret); } @@ -905,7 +910,7 @@ static efi_status_t efi_set_variable_common(u16 *variable_name, old_size = 0; attr = 0; ret = efi_get_variable_common(variable_name, vendor, &attr, - &old_size, NULL); + &old_size, NULL, &time); append = !!(attributes & EFI_VARIABLE_APPEND_WRITE); attributes &= ~(u32)EFI_VARIABLE_APPEND_WRITE; delete = !append && (!data_size || !attributes); @@ -996,7 +1001,7 @@ static efi_status_t efi_set_variable_common(u16 *variable_name, goto err; } ret = efi_get_variable_common(variable_name, vendor, - &attr, &old_size, old_data); + &attr, &old_size, old_data, NULL); if (ret != EFI_SUCCESS) goto err; } else { -- 2.39.5