[RFC PATCH 3/3] eficonfig: add "Delete Key" menu entry
Heinrich Schuchardt
xypron.glpk at gmx.de
Sun Jul 10 12:10:13 CEST 2022
On 6/19/22 07:20, Masahisa Kojima wrote:
> This commit add the menu-driven interface to delete the
> signature database entry.
> EFI Signature Lists can contain the multiple signature
> entries, this menu can delete the indivisual entry.
>
> If the PK is enrolled and UEFI Secure Boot is in User Mode,
Why don't you mention Deployed Mode?
> user can not delete the existing signature lists since the
> signature lists must be signed by KEK or PK but signing
> information is not stored in the signature database.
Updating PK with an empty value must be possible if if the new value is
signed with the old PK.
>
> Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
> ---
> cmd/eficonfig_sbkey.c | 218 +++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 217 insertions(+), 1 deletion(-)
>
> diff --git a/cmd/eficonfig_sbkey.c b/cmd/eficonfig_sbkey.c
> index 02ab8f8218..142bb4cef5 100644
> --- a/cmd/eficonfig_sbkey.c
> +++ b/cmd/eficonfig_sbkey.c
> @@ -54,6 +54,29 @@ static const struct eficonfig_sigtype_to_str sigtype_to_str[] = {
> /* {EFI_CERT_SHA512_GUID, "SHA512", SIG_TYPE_HASH}, */
> };
>
Please, add documentation to all functions.
> +static int eficonfig_console_yes_no(void)
> +{
> + int esc = 0;
> + enum bootmenu_key key = KEY_NONE;
> +
> + while (1) {
> + bootmenu_loop(NULL, &key, &esc);
> +
> + switch (key) {
> + case KEY_SELECT:
> + return 1;
> + case KEY_QUIT:
> + return 0;
> + default:
> + break;
> + }
> + }
> +
> + /* never happens */
> + debug("eficonfig: this should not happen");
> + return 0;
If this code is unreachable, remove it.
> +}
> +
> static void eficonfig_console_wait_enter(void)
> {
> int esc = 0;
> @@ -72,7 +95,19 @@ static void eficonfig_console_wait_enter(void)
>
> /* never happens */
> debug("eficonfig: this should not happen");
> - return;
Please remove unreachable code.
> +}
> +
> +static bool is_setupmode(void)
> +{
> + efi_status_t ret;
> + u8 setup_mode;
> + efi_uintn_t size;
> +
> + size = sizeof(setup_mode);
> + ret = efi_get_variable_int(u"SetupMode", &efi_global_variable_guid,
> + NULL, &size, &setup_mode, NULL);
> +
> + return setup_mode == 1;
> }
>
> static bool is_secureboot_enabled(void)
> @@ -254,6 +289,103 @@ static efi_status_t eficonfig_process_sigdata_show(void *data)
> return EFI_SUCCESS;
> }
>
> +static efi_status_t eficonfig_process_sigdata_delete(void *data)
> +{
> + int yes_no;
> + struct eficonfig_sig_data *sg = data;
> +
> + display_sigdata_header(sg, "Delete");
> + display_sigdata_info(sg);
> +
> + printf("\n\n Press ENTER to delete, ESC/CTRL+C to quit");
> + yes_no = eficonfig_console_yes_no();
> + if (!yes_no)
> + return EFI_NOT_READY;
> +
> + return EFI_SUCCESS;
> +}
> +
> +static void delete_selected_signature_data(void *db, efi_uintn_t *db_size,
> + struct eficonfig_sig_data *target,
> + struct list_head *siglist_list)
> +{
> + u8 *dest, *start;
> + struct list_head *pos, *n;
> + u32 remain;
> + u32 size = *db_size;
> + u8 *end = (u8 *)db + size;
> + struct eficonfig_sig_data *sg;
> +
> + list_for_each_safe(pos, n, siglist_list) {
> + sg = list_entry(pos, struct eficonfig_sig_data, list);
> + if (sg->esl == target->esl && sg->esd == target->esd) {
> + remain = sg->esl->signature_list_size -
> + (sizeof(struct efi_signature_list) -
> + sg->esl->signature_header_size) -
> + sg->esl->signature_size;
> + if (remain > 0) {
> + /* only delete the single signature data */
> + sg->esl->signature_list_size -= sg->esl->signature_size;
> + size -= sg->esl->signature_size;
> + dest = (u8 *)sg->esd;
> + start = (u8 *)sg->esd + sg->esl->signature_size;
> + } else {
> + /* delete entire signature list */
> + dest = (u8 *)sg->esl;
> + start = (u8 *)sg->esl + sg->esl->signature_list_size;
> + size -= sg->esl->signature_list_size;
> + }
> + memmove(dest, start, (end - start));
> + }
> + }
> +
> + *db_size = size;
> +}
> +
> +static efi_status_t create_time_based_payload(void *db, void **new_db, efi_uintn_t *size)
> +{
> + efi_status_t ret;
> + struct efi_time time;
> + efi_uintn_t total_size;
> + struct efi_variable_authentication_2 *auth;
> +
> + *new_db = NULL;
> +
> + /*
> + * SetVariable() call with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
> + * attribute requires EFI_VARIABLE_AUTHENTICATED_2 descriptor, prepare it
> + * without certificate data in it.
> + */
> + total_size = sizeof(struct efi_variable_authentication_2) + *size;
> +
> + auth = calloc(1, total_size);
> + if (!auth)
> + return EFI_OUT_OF_RESOURCES;
> +
> + ret = EFI_CALL((*efi_runtime_services.get_time)(&time, NULL));
> + if (ret != EFI_SUCCESS) {
> + free(auth);
> + return EFI_OUT_OF_RESOURCES;
> + }
> + time.pad1 = 0;
> + time.nanosecond = 0;
> + time.timezone = 0;
> + time.daylight = 0;
> + time.pad2 = 0;
> + memcpy(&auth->time_stamp, &time, sizeof(time));
> + auth->auth_info.hdr.dwLength = sizeof(struct win_certificate_uefi_guid);
> + auth->auth_info.hdr.wRevision = 0x0200;
> + auth->auth_info.hdr.wCertificateType = WIN_CERT_TYPE_EFI_GUID;
> + guidcpy(&auth->auth_info.cert_type, &efi_guid_cert_type_pkcs7);
> + if (db)
> + memcpy((u8 *)auth + sizeof(struct efi_variable_authentication_2), db, *size);
> +
> + *new_db = auth;
> + *size = total_size;
> +
> + return EFI_SUCCESS;
> +}
> +
> static efi_status_t prepare_signature_db_list(struct eficonfig_item **output, void *varname,
> void *db, efi_uintn_t db_size,
> eficonfig_entry_func func,
> @@ -378,6 +510,68 @@ out:
> return ret;
> }
>
> +static efi_status_t process_delete_key(void *varname)
> +{
> + u32 attr, i, count = 0;
> + efi_status_t ret;
> + struct eficonfig_item *menu_item = NULL, *iter;
> + void *db = NULL, *new_db = NULL;
> + efi_uintn_t db_size;
> + struct list_head siglist_list;
> + struct eficonfig_sig_data *selected;
> +
> + db = efi_get_var(varname, efi_auth_var_get_guid(varname), &db_size);
> + if (!db) {
> + eficonfig_print_msg("There is no entry in the signature database.");
Please, use the terms of the UEFI specification.
%s/signature database/signature store/
> + return EFI_NOT_FOUND;
> + }
> +
> + ret = prepare_signature_db_list(&menu_item, varname, db, db_size,
> + eficonfig_process_sigdata_delete, &selected,
> + &siglist_list, &count);
> + if (ret != EFI_SUCCESS)
> + goto out;
> +
> + ret = eficonfig_process_common(menu_item, count, " ** Delete Key **");
> +
> + if (ret == EFI_SUCCESS) {
> + delete_selected_signature_data(db, &db_size, selected, &siglist_list);
> +
> + ret = create_time_based_payload(db, &new_db, &db_size);
> + if (ret != EFI_SUCCESS)
> + goto out;
> +
> + attr = EFI_VARIABLE_NON_VOLATILE |
> + EFI_VARIABLE_BOOTSERVICE_ACCESS |
> + EFI_VARIABLE_RUNTIME_ACCESS |
> + EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
> + ret = efi_set_variable_int((u16 *)varname, efi_auth_var_get_guid((u16 *)varname),
> + attr, db_size, new_db, false);
> + if (ret != EFI_SUCCESS) {
> + eficonfig_print_msg("ERROR! Fail to delete signature database");
%s/Fail/Failed/
Please, use the terms of the UEFI specification.
%s/signature database/signature store/
> + goto out;
> + }
> + }
> +
> +out:
> + if (menu_item) {
> + iter = menu_item;
> + for (i = 0; i < count - 1; iter++, i++) {
> + free(iter->title);
> + free(iter->data);
> + }
> + }
> +
> + free(menu_item);
> + free(db);
> + free(new_db);
> +
> + /* to stay the parent menu */
> + ret = (ret == EFI_ABORTED) ? EFI_NOT_READY : ret;
> +
> + return ret;
> +}
> +
> static efi_status_t eficonfig_process_show_signature_db(void *data)
> {
> efi_status_t ret;
> @@ -394,6 +588,27 @@ static efi_status_t eficonfig_process_show_signature_db(void *data)
> return ret;
> }
>
> +static efi_status_t eficonfig_process_delete_key(void *data)
> +{
> + efi_status_t ret;
> +
> + if (!is_setupmode()) {
> + eficonfig_print_msg("Not in the SetupMode, can not delete.");
Both in Setup Mode and in Audit Mode you should be able to edit keys.
> + return EFI_SUCCESS;
> + }
> +
> + while (1) {
> + ret = process_delete_key(data);
> + if (ret != EFI_SUCCESS)
> + break;
> + }
> +
> + /* to stay the parent menu */
> + ret = (ret == EFI_ABORTED) ? EFI_NOT_READY : ret;
> +
> + return ret;
> +}
> +
> static struct eficonfig_item key_config_pk_menu_items[] = {
> {"Enroll New Key", eficonfig_process_enroll_key},
> {"Show Signature Database", eficonfig_process_show_signature_db},
%s/Signature Database/signature store/
> @@ -403,6 +618,7 @@ static struct eficonfig_item key_config_pk_menu_items[] = {
> static struct eficonfig_item key_config_menu_items[] = {
> {"Enroll New Key", eficonfig_process_enroll_key},
> {"Show Signature Database", eficonfig_process_show_signature_db},
%s/Signature Database/signature store/
Best regards
Heinrich
> + {"Delete Key", eficonfig_process_delete_key},
> {"Quit", eficonfig_process_quit},
> };
>
More information about the U-Boot
mailing list