[RFC PATCH 3/3] eficonfig: add "Delete Key" menu entry
Takahiro Akashi
takahiro.akashi at linaro.org
Tue Jul 12 03:17:33 CEST 2022
On Sun, Jul 10, 2022 at 12:10:13PM +0200, Heinrich Schuchardt wrote:
> 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/
Signature database is also a common term throughout the specification.
See "section 32.4.1 Signature Database", for example.
-Takahiro Akashi
> > + 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