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efi/x86: Add a quirk to support command line arguments on Dell EFI firmware

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At least some versions of Dell EFI firmware pass the entire
EFI_LOAD_OPTION descriptor, rather than just the OptionalData part, to
the loaded image. This was verified with firmware revision 2.15.0 on a
Dell Precision T3620 by Jacobo Pantoja.

To handle this, add a quirk to check if the options look like a valid
EFI_LOAD_OPTION descriptor, and if so, use the OptionalData part as the
command line.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Reported-by: Jacobo Pantoja <jacobopantoja@gmail.com>
Link: https://lore.kernel.org/linux-efi/20200907170021.GA2284449@rani.riverdale.lan/
Link: https://lore.kernel.org/r/20200914213535.933454-2-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Arvind Sankar 2020-09-14 17:35:35 -04:00 committed by Ard Biesheuvel
parent c1df5e0c57
commit 4a568ce29d
3 changed files with 135 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

101
drivers/firmware/efi/libstub/efi-stub-helper.c
View File

@ -230,6 +230,102 @@ efi_status_t efi_parse_options(char const *cmdline)
return EFI_SUCCESS;
}
/*
* The EFI_LOAD_OPTION descriptor has the following layout:
* u32 Attributes;
* u16 FilePathListLength;
* u16 Description[];
* efi_device_path_protocol_t FilePathList[];
* u8 OptionalData[];
*
* This function validates and unpacks the variable-size data fields.
*/
static
bool efi_load_option_unpack(efi_load_option_unpacked_t *dest,
const efi_load_option_t *src, size_t size)
{
const void *pos;
u16 c;
efi_device_path_protocol_t header;
const efi_char16_t *description;
const efi_device_path_protocol_t *file_path_list;
if (size < offsetof(efi_load_option_t, variable_data))
return false;
pos = src->variable_data;
size -= offsetof(efi_load_option_t, variable_data);
if ((src->attributes & ~EFI_LOAD_OPTION_MASK) != 0)
return false;
/* Scan description. */
description = pos;
do {
if (size < sizeof(c))
return false;
c = *(const u16 *)pos;
pos += sizeof(c);
size -= sizeof(c);
} while (c != L'\0');
/* Scan file_path_list. */
file_path_list = pos;
do {
if (size < sizeof(header))
return false;
header = *(const efi_device_path_protocol_t *)pos;
if (header.length < sizeof(header))
return false;
if (size < header.length)
return false;
pos += header.length;
size -= header.length;
} while ((header.type != EFI_DEV_END_PATH && header.type != EFI_DEV_END_PATH2) ||
(header.sub_type != EFI_DEV_END_ENTIRE));
if (pos != (const void *)file_path_list + src->file_path_list_length)
return false;
dest->attributes = src->attributes;
dest->file_path_list_length = src->file_path_list_length;
dest->description = description;
dest->file_path_list = file_path_list;
dest->optional_data_size = size;
dest->optional_data = size ? pos : NULL;
return true;
}
/*
* At least some versions of Dell firmware pass the entire contents of the
* Boot#### variable, i.e. the EFI_LOAD_OPTION descriptor, rather than just the
* OptionalData field.
*
* Detect this case and extract OptionalData.
*/
void efi_apply_loadoptions_quirk(const void **load_options, int *load_options_size)
{
const efi_load_option_t *load_option = *load_options;
efi_load_option_unpacked_t load_option_unpacked;
if (!IS_ENABLED(CONFIG_X86))
return;
if (!load_option)
return;
if (*load_options_size < sizeof(*load_option))
return;
if ((load_option->attributes & ~EFI_LOAD_OPTION_BOOT_MASK) != 0)
return;
if (!efi_load_option_unpack(&load_option_unpacked, load_option, *load_options_size))
return;
efi_warn_once(FW_BUG "LoadOptions is an EFI_LOAD_OPTION descriptor\n");
efi_warn_once(FW_BUG "Using OptionalData as a workaround\n");
*load_options = load_option_unpacked.optional_data;
*load_options_size = load_option_unpacked.optional_data_size;
}
/*
* Convert the unicode UEFI command line to ASCII to pass to kernel.
* Size of memory allocated return in *cmd_line_len.
@ -239,12 +335,15 @@ char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len)
{
const u16 *s2;
unsigned long cmdline_addr = 0;
int options_chars = efi_table_attr(image, load_options_size) / 2;
int options_chars = efi_table_attr(image, load_options_size);
const u16 *options = efi_table_attr(image, load_options);
int options_bytes = 0, safe_options_bytes = 0; /* UTF-8 bytes */
bool in_quote = false;
efi_status_t status;
efi_apply_loadoptions_quirk((const void **)&options, &options_chars);
options_chars /= sizeof(*options);
if (options) {
s2 = options;
while (options_bytes < COMMAND_LINE_SIZE && options_chars--) {

31
drivers/firmware/efi/libstub/efistub.h
View File

@ -708,6 +708,35 @@ union efi_load_file_protocol {
} mixed_mode;
};
typedef struct {
u32 attributes;
u16 file_path_list_length;
u8 variable_data[];
// efi_char16_t description[];
// efi_device_path_protocol_t file_path_list[];
// u8 optional_data[];
} __packed efi_load_option_t;
#define EFI_LOAD_OPTION_ACTIVE 0x0001U
#define EFI_LOAD_OPTION_FORCE_RECONNECT 0x0002U
#define EFI_LOAD_OPTION_HIDDEN 0x0008U
#define EFI_LOAD_OPTION_CATEGORY 0x1f00U
#define EFI_LOAD_OPTION_CATEGORY_BOOT 0x0000U
#define EFI_LOAD_OPTION_CATEGORY_APP 0x0100U
#define EFI_LOAD_OPTION_BOOT_MASK \
(EFI_LOAD_OPTION_ACTIVE|EFI_LOAD_OPTION_HIDDEN|EFI_LOAD_OPTION_CATEGORY)
#define EFI_LOAD_OPTION_MASK (EFI_LOAD_OPTION_FORCE_RECONNECT|EFI_LOAD_OPTION_BOOT_MASK)
typedef struct {
u32 attributes;
u16 file_path_list_length;
const efi_char16_t *description;
const efi_device_path_protocol_t *file_path_list;
size_t optional_data_size;
const void *optional_data;
} efi_load_option_unpacked_t;
void efi_pci_disable_bridge_busmaster(void);
typedef efi_status_t (*efi_exit_boot_map_processing)(
@ -750,6 +779,8 @@ __printf(1, 2) int efi_printk(char const *fmt, ...);
void efi_free(unsigned long size, unsigned long addr);
void efi_apply_loadoptions_quirk(const void **load_options, int *load_options_size);
char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len);
efi_status_t efi_get_memory_map(struct efi_boot_memmap *map);

5
drivers/firmware/efi/libstub/file.c
View File

@ -136,7 +136,7 @@ efi_status_t handle_cmdline_files(efi_loaded_image_t *image,
unsigned long *load_size)
{
const efi_char16_t *cmdline = image->load_options;
int cmdline_len = image->load_options_size / 2;
int cmdline_len = image->load_options_size;
unsigned long efi_chunk_size = ULONG_MAX;
efi_file_protocol_t *volume = NULL;
efi_file_protocol_t *file;
@ -148,6 +148,9 @@ efi_status_t handle_cmdline_files(efi_loaded_image_t *image,
if (!load_addr || !load_size)
return EFI_INVALID_PARAMETER;
efi_apply_loadoptions_quirk((const void **)&cmdline, &cmdline_len);
cmdline_len /= sizeof(*cmdline);
if (IS_ENABLED(CONFIG_X86) && !efi_nochunk)
efi_chunk_size = EFI_READ_CHUNK_SIZE;