[PATCH v5 16/17] bootmenu: add removable media entries
Heinrich Schuchardt
xypron.glpk at gmx.de
Mon May 9 15:01:08 CEST 2022
On 5/9/22 10:23, Masahisa Kojima wrote:
> On Fri, 29 Apr 2022 at 01:53, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
>>
>> On 4/28/22 10:09, Masahisa Kojima wrote:
>>> UEFI specification requires booting from removal media using
>>> a architecture-specific default image name such as BOOTAA64.EFI.
>>> This commit adds the removable media entries into bootmenu,
>>> so that user can select the removable media and boot with
>>> default image.
>>>
>>> The bootmenu automatically enumerates the possible bootable
>>> media devices supporting EFI_SIMPLE_FILE_SYSTEM_PROTOCOL,
>>> add it as new UEFI boot option(BOOT####) and update BootOrder
>>> variable. This automatically generated UEFI boot option
>>> has the dedicated guid in the optional_data to distinguish it from
>>> the UEFI boot option user adds manually.
>>>
>>> This commit also provides the BOOT#### variable maintenance feature.
>>> Depending on the system hardware setup, some devices
>>> may not exist at a later system boot, so bootmenu checks the
>>> available device in each bootmenu invocation and automatically
>>> removes the BOOT#### variable corrensponding to the non-existent
>>> media device.
>>>
>>> Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
>>> ---
>>> Changes in v5:
>>> - Return EFI_SUCCESS if there is no BootOrder defined
>>> - correctly handle the case if no removable device found
>>> - use guid to identify the automatically generated entry by bootmenu
>>>
>>> Newly created in v4
>>>
>>> cmd/bootmenu.c | 94 +++++++++++++++
>>> include/efi_loader.h | 20 ++++
>>> lib/efi_loader/efi_bootmenu_maintenance.c | 139 ++++++++++++++++++++++
>>> 3 files changed, 253 insertions(+)
>>>
>>> diff --git a/cmd/bootmenu.c b/cmd/bootmenu.c
>>> index 860cb83182..970db3ee01 100644
>>> --- a/cmd/bootmenu.c
>>> +++ b/cmd/bootmenu.c
>>> @@ -396,6 +396,89 @@ static int is_blk_device_available(char *token)
>>> return -ENODEV;
>>> }
>>>
>>> +/**
>>> + * prepare_media_device_entry() - generate the media device entries
>>> + *
>>> + * This function enumerates all devices supporting EFI_SIMPLE_FILE_SYSTEM_PROTOCOL
>>> + * and generate the bootmenu entries.
>>> + * This function also provide the BOOT#### variable maintenance for
>>> + * the media device entries.
>>> + * - Automatically create the BOOT#### variable for the newly detected device,
>>> + * this BOOT#### variable is distinguished by the special GUID
>>> + * stored in the EFI_LOAD_OPTION.optional_data
>>> + * - If the device is not attached to the system, the associated BOOT#### variable
>>> + * is automatically deleted.
>>> + *
>>> + * Return: status code
>>> + */
>>> +static efi_status_t prepare_media_device_entry(void)
>>> +{
>>> + u32 i;
>>> + efi_status_t ret;
>>> + efi_uintn_t count;
>>> + efi_handle_t *volume_handles = NULL;
>>> + struct efi_bootmenu_media_boot_option *opt = NULL;
>>> +
>>> + ret = efi_locate_handle_buffer_int(BY_PROTOCOL, &efi_simple_file_system_protocol_guid,
>>> + NULL, &count, (efi_handle_t **)&volume_handles);
>>> + if (ret != EFI_SUCCESS)
>>> + return ret;
>>> +
>>> + opt = calloc(count, sizeof(struct efi_bootmenu_media_boot_option));
>>> + if (!opt)
>>> + goto out;
>>> +
>>> + /* enumerate all devices supporting EFI_SIMPLE_FILE_SYSTEM_PROTOCOL */
>>> + ret = efi_bootmenu_enumerate_boot_option(opt, volume_handles, count);
>>> + if (ret != EFI_SUCCESS)
>>> + goto out;
>>> +
>>> + /*
>>> + * System hardware configuration may vary depending on the user setup.
>>> + * The boot option is automatically added by the bootmenu.
>>> + * If the device is not attached to the system, the boot option needs
>>> + * to be deleted.
>>> + */
>>> + ret = efi_bootmenu_delete_invalid_boot_option(opt, count);
>>> + if (ret != EFI_SUCCESS)
>>> + goto out;
>>> +
>>> + /* add non-existent boot option */
>>> + for (i = 0; i < count; i++) {
>>> + u32 boot_index;
>>> + u16 var_name[9];
>>> +
>>> + if (!opt[i].exist) {
>>> + ret = efi_bootmenu_get_unused_bootoption(var_name, sizeof(var_name),
>>> + &boot_index);
>>> + if (ret != EFI_SUCCESS)
>>> + goto out;
>>> +
>>> + ret = efi_set_variable_int(var_name, &efi_global_variable_guid,
>>> + EFI_VARIABLE_NON_VOLATILE |
>>> + EFI_VARIABLE_BOOTSERVICE_ACCESS |
>>> + EFI_VARIABLE_RUNTIME_ACCESS,
>>> + opt[i].size, opt[i].lo, false);
>>> + if (ret != EFI_SUCCESS)
>>> + goto out;
>>> +
>>> + ret = efi_bootmenu_append_bootorder(boot_index);
>>> + if (ret != EFI_SUCCESS)
>>> + goto out;
>>> + }
>>> + }
>>> +
>>> +out:
>>> + if (opt) {
>>> + for (i = 0; i < count; i++)
>>> + free(opt[i].lo);
>>> + }
>>> + free(opt);
>>> + efi_free_pool(volume_handles);
>>> +
>>> + return ret;
>>> +}
>>> +
>>> /**
>>> * prepare_distro_boot_entry() - generate the distro boot entries
>>> *
>>> @@ -500,6 +583,7 @@ static int prepare_distro_boot_entry(struct bootmenu_data *menu,
>>> static struct bootmenu_data *bootmenu_create(int delay)
>>> {
>>> int ret;
>>> + efi_status_t efi_ret;
>>> unsigned short int i = 0;
>>> struct bootmenu_data *menu;
>>> struct bootmenu_entry *iter = NULL;
>>> @@ -523,6 +607,16 @@ static struct bootmenu_data *bootmenu_create(int delay)
>>> goto cleanup;
>>>
>>> if (IS_ENABLED(CONFIG_CMD_BOOTEFI_BOOTMGR)) {
>>> + if (i < MAX_DYNAMIC_ENTRY) {
>>> + /*
>>> + * UEFI specification requires booting from removal media using
>>> + * a architecture-specific default image name such as BOOTAA64.EFI.
>>> + */
>>> + efi_ret = prepare_media_device_entry();
>>> + if (efi_ret != EFI_SUCCESS && efi_ret != EFI_NOT_FOUND)
>>> + goto cleanup;
>>> + }
>>> +
>>> if (i < MAX_DYNAMIC_ENTRY) {
>>> ret = prepare_uefi_bootorder_entry(menu, &iter, &i);
>>> if (ret < 0 && ret != -ENOENT)
>>> diff --git a/include/efi_loader.h b/include/efi_loader.h
>>> index 533618341b..bef492ccb9 100644
>>> --- a/include/efi_loader.h
>>> +++ b/include/efi_loader.h
>>> @@ -928,6 +928,22 @@ struct efi_signature_store {
>>> struct x509_certificate;
>>> struct pkcs7_message;
>>>
>>> +/**
>>> + * struct efi_bootmenu_media_boot_option - boot option for (removable) media device
>>> + *
>>> + * This structure is used to enumerate possible boot option
>>> + *
>>> + * @lo: Serialized load option data
>>> + * @size: Size of serialized load option data
>>> + * @exist: Flag to indicate the load option already exists
>>> + * in Non-volatile load option
>>> + */
>>> +struct efi_bootmenu_media_boot_option {
>>> + void *lo;
>>> + efi_uintn_t size;
>>> + bool exist;
>>> +};
>>> +
>>> bool efi_signature_lookup_digest(struct efi_image_regions *regs,
>>> struct efi_signature_store *db,
>>> bool dbx);
>>> @@ -1076,6 +1092,10 @@ efi_status_t efi_console_get_u16_string
>>> efi_status_t efi_bootmenu_get_unused_bootoption(u16 *buf,
>>> efi_uintn_t buf_size, u32 *index);
>>> efi_status_t efi_bootmenu_append_bootorder(u16 index);
>>> +efi_status_t efi_bootmenu_enumerate_boot_option(struct efi_bootmenu_media_boot_option *opt,
>>> + efi_handle_t *volume_handles, efi_status_t count);
>>> +efi_status_t efi_bootmenu_delete_invalid_boot_option(struct efi_bootmenu_media_boot_option *opt,
>>> + efi_status_t count);
>>>
>>> efi_status_t efi_disk_get_device_name(struct efi_block_io *this, char *buf, int size);
>>>
>>> diff --git a/lib/efi_loader/efi_bootmenu_maintenance.c b/lib/efi_loader/efi_bootmenu_maintenance.c
>>> index 8c3f94c695..33b37fd11a 100644
>>> --- a/lib/efi_loader/efi_bootmenu_maintenance.c
>>> +++ b/lib/efi_loader/efi_bootmenu_maintenance.c
>>> @@ -26,6 +26,13 @@ static struct efi_simple_text_output_protocol *cout;
>>> #define EFI_BOOTMENU_BOOT_NAME_MAX 32
>>> #define EFI_BOOT_ORDER_MAX_SIZE_IN_DECIMAL 6
>>>
>>> +#define EFI_BOOTMENU_AUTO_GENERATED_ENTRY_GUID \
>>> + EFI_GUID(0x38c1acc1, 0x9fc0, 0x41f0, \
>>> + 0xb9, 0x01, 0xfa, 0x74, 0xd6, 0xd6, 0xe4, 0xde)
>>> +
>>> +static const efi_guid_t efi_guid_bootmenu_auto_generated =
>>> + EFI_BOOTMENU_AUTO_GENERATED_ENTRY_GUID;
>>> +
>>> typedef efi_status_t (*efi_bootmenu_entry_func)(void *data, bool *exit);
>>>
>>> /**
>>> @@ -1104,3 +1111,135 @@ efi_status_t efi_bootmenu_show_maintenance_menu(void)
>>> ARRAY_SIZE(maintenance_menu_items),
>>> -1);
>>> }
>>> +
>>> +efi_status_t efi_bootmenu_enumerate_boot_option(struct efi_bootmenu_media_boot_option *opt,
>>> + efi_handle_t *volume_handles, efi_status_t count)
>>> +{
>>> + u32 i;
>>> + struct efi_handler *handler;
>>> + efi_status_t ret = EFI_SUCCESS;
>>> +
>>> + for (i = 0; i < count; i++) {
>>> + char *optional_data;
>>> + u16 *dev_name, *p;
>>> + struct efi_load_option lo;
>>> + struct efi_block_io *block_io;
>>> + char buf[BOOTMENU_DEVICE_NAME_MAX];
>>> + struct efi_device_path *device_path;
>>> +
>>> + ret = efi_search_protocol(volume_handles[i], &efi_guid_device_path, &handler);
>>> + if (ret != EFI_SUCCESS)
>>> + continue;
>>> + ret = efi_protocol_open(handler, (void **)&device_path,
>>> + efi_root, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
>>> + if (ret != EFI_SUCCESS)
>>> + continue;
>>> +
>>> + ret = efi_search_protocol(volume_handles[i], &efi_block_io_guid, &handler);
>>> + if (ret != EFI_SUCCESS)
>>> + continue;
>>> + ret = efi_protocol_open(handler, (void **)&block_io,
>>> + efi_root, NULL, EFI_OPEN_PROTOCOL_GET_PROTOCOL);
>>> + if (ret != EFI_SUCCESS)
>>> + continue;
>>> +
>>> + efi_disk_get_device_name(block_io, buf, BOOTMENU_DEVICE_NAME_MAX);
>>> + dev_name = calloc(1, (strlen(buf) + 1) * sizeof(u16));
>>> + if (!dev_name) {
>>> + ret = EFI_OUT_OF_RESOURCES;
>>> + goto out;
>>> + }
>>> + p = dev_name;
>>> + utf8_utf16_strncpy(&p, buf, strlen(buf));
>>> +
>>> + lo.label = dev_name;
>>> + lo.attributes = LOAD_OPTION_ACTIVE;
>>> + lo.file_path = device_path;
>>> + lo.file_path_length = efi_dp_size(device_path) + sizeof(END);
>>> + /*
>>> + * Set the dedicated guid to optional_data, it is used to identify
>>> + * the boot option that automatically generated by the bootmenu.
>>> + * efi_serialize_load_option() expects optional_data is null-terminated
>>> + * utf8 string, so set the "dummystr" string to allocate enough space
>>> + * to store guid, instead of realloc the load_option.
>>> + *
>>> + * This will allocate 16 bytes for guid plus trailing 0x0000.
>>> + * The guid does not require trailing 0x0000, but it is for safety
>>> + * in case some program handle the optional_data as u16 string.
>>> + */
>>> + lo.optional_data = "dummystr";
>>
>> Why do you want to reserve 18 bytes when 16 are enough for the GUID?
>
> OK, I will only allocate 16 bytes for GUID.
>
>>
>>> + opt[i].size = efi_serialize_load_option(&lo, (u8 **)&opt[i].lo);
>>> + if (!opt[i].size) {
>>> + ret = EFI_OUT_OF_RESOURCES;
>>> + free(dev_name);
>>> + goto out;
>>> + }
>>> + /* set the guid */
>>> + optional_data = (char *)opt[i].lo + (opt[i].size - u16_strsize(u"dummystr"));
>>> + memcpy(optional_data, &efi_guid_bootmenu_auto_generated, sizeof(efi_guid_t));
>>> + free(dev_name);
>>> + }
>>> +
>>> +out:
>>> + return ret;
>>> +}
>>> +
>>> +efi_status_t efi_bootmenu_delete_invalid_boot_option(struct efi_bootmenu_media_boot_option *opt,
>>> + efi_status_t count)
>>> +{
>>> + u16 *bootorder;
>>> + u32 i, j;
>>> + efi_status_t ret;
>>> + efi_uintn_t num, size, bootorder_size;
>>> + void *load_option;
>>> + struct efi_load_option lo;
>>> + u16 varname[] = u"Boot####";
>>> +
>>> + bootorder = efi_get_var(u"BootOrder", &efi_global_variable_guid, &bootorder_size);
>>> + if (!bootorder)
>>> + return EFI_SUCCESS; /* BootOrder is not defined, nothing to do */
>>> +
>>> + num = bootorder_size / sizeof(u16);
>>> + for (i = 0; i < num;) {
>>> + efi_uintn_t tmp;
>>> +
>>> + efi_create_indexed_name(varname, sizeof(varname),
>>> + "Boot", bootorder[i]);
>>> + load_option = efi_get_var(varname, &efi_global_variable_guid, &size);
>>> + if (!load_option)
>>> + goto next;
>>> +
>>> + tmp = size;
>>
>> This copying of variables is superfluous. Just keep size.
>
> I don't catch your point.
> This efi_bootmenu_delete_invalid_boot_option() function
> does not copy the variable, only keeps the variable size.
There is no need to copy the value of variable size to a new variable
tmp. You can remove the variable tmp and continue using variable size
below as both variables are of the same type.
Best regards
Heinrich
>
>>
>>> + ret = efi_deserialize_load_option(&lo, load_option, &tmp);
>>> + if (ret != EFI_SUCCESS)
>>> + goto next;
>>> +
>>> + if (guidcmp(lo.optional_data, &efi_guid_bootmenu_auto_generated) == 0) {
>>
>> You must avoid a buffer overrun. Check size >= 16.
>
> Yes, I need to check the size of optional_data.
>
> Thanks,
> Masahisa Kojima
>
>>
>> Best regards
>>
>> Heinrich
>>
>>> + for (j = 0; j < count; j++) {
>>> + if (memcmp(opt[j].lo, load_option, size) == 0) {
>>> + opt[j].exist = true;
>>> + break;
>>> + }
>>> + }
>>> +
>>> + if (j == count) {
>>> + ret = delete_boot_option(bootorder, i, bootorder_size);
>>> + if (ret != EFI_SUCCESS) {
>>> + free(load_option);
>>> + goto out;
>>> + }
>>> +
>>> + num--;
>>> + bootorder_size -= sizeof(u16);
>>> + free(load_option);
>>> + continue;
>>> + }
>>> + }
>>> +next:
>>> + free(load_option);
>>> + i++;
>>> + }
>>> +
>>> +out:
>>> + return ret;
>>> +}
>>
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