diff options
Diffstat (limited to 'drivers/firmware/efi/libstub/efi-stub-helper.c')
| -rw-r--r-- | drivers/firmware/efi/libstub/efi-stub-helper.c | 655 |
1 files changed, 443 insertions, 212 deletions
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index 89f075275300..7aa2f9ad2935 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -7,177 +7,69 @@ * Copyright 2011 Intel Corporation; author Matt Fleming */ -#include <stdarg.h> +#include <linux/stdarg.h> -#include <linux/ctype.h> #include <linux/efi.h> #include <linux/kernel.h> -#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */ +#include <linux/overflow.h> #include <asm/efi.h> #include <asm/setup.h> #include "efistub.h" bool efi_nochunk; -bool efi_nokaslr; -bool efi_noinitrd; -int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT; +bool efi_nokaslr = !IS_ENABLED(CONFIG_RANDOMIZE_BASE); bool efi_novamap; +static bool efi_noinitrd; static bool efi_nosoftreserve; static bool efi_disable_pci_dma = IS_ENABLED(CONFIG_EFI_DISABLE_PCI_DMA); +int efi_mem_encrypt; + bool __pure __efi_soft_reserve_enabled(void) { return !efi_nosoftreserve; } -void efi_char16_puts(efi_char16_t *str) -{ - efi_call_proto(efi_table_attr(efi_system_table, con_out), - output_string, str); -} - -static -u32 utf8_to_utf32(const u8 **s8) -{ - u32 c32; - u8 c0, cx; - size_t clen, i; - - c0 = cx = *(*s8)++; - /* - * The position of the most-significant 0 bit gives us the length of - * a multi-octet encoding. - */ - for (clen = 0; cx & 0x80; ++clen) - cx <<= 1; - /* - * If the 0 bit is in position 8, this is a valid single-octet - * encoding. If the 0 bit is in position 7 or positions 1-3, the - * encoding is invalid. - * In either case, we just return the first octet. - */ - if (clen < 2 || clen > 4) - return c0; - /* Get the bits from the first octet. */ - c32 = cx >> clen--; - for (i = 0; i < clen; ++i) { - /* Trailing octets must have 10 in most significant bits. */ - cx = (*s8)[i] ^ 0x80; - if (cx & 0xc0) - return c0; - c32 = (c32 << 6) | cx; - } - /* - * Check for validity: - * - The character must be in the Unicode range. - * - It must not be a surrogate. - * - It must be encoded using the correct number of octets. - */ - if (c32 > 0x10ffff || - (c32 & 0xf800) == 0xd800 || - clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000)) - return c0; - *s8 += clen; - return c32; -} - -void efi_puts(const char *str) -{ - efi_char16_t buf[128]; - size_t pos = 0, lim = ARRAY_SIZE(buf); - const u8 *s8 = (const u8 *)str; - u32 c32; - - while (*s8) { - if (*s8 == '\n') - buf[pos++] = L'\r'; - c32 = utf8_to_utf32(&s8); - if (c32 < 0x10000) { - /* Characters in plane 0 use a single word. */ - buf[pos++] = c32; - } else { - /* - * Characters in other planes encode into a surrogate - * pair. - */ - buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10); - buf[pos++] = 0xdc00 + (c32 & 0x3ff); - } - if (*s8 == '\0' || pos >= lim - 2) { - buf[pos] = L'\0'; - efi_char16_puts(buf); - pos = 0; - } - } -} - -int efi_printk(const char *fmt, ...) -{ - char printf_buf[256]; - va_list args; - int printed; - int loglevel = printk_get_level(fmt); - - switch (loglevel) { - case '0' ... '9': - loglevel -= '0'; - break; - default: - /* - * Use loglevel -1 for cases where we just want to print to - * the screen. - */ - loglevel = -1; - break; - } - - if (loglevel >= efi_loglevel) - return 0; - - if (loglevel >= 0) - efi_puts("EFI stub: "); - - fmt = printk_skip_level(fmt); - - va_start(args, fmt); - printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args); - va_end(args); - - efi_puts(printf_buf); - if (printed >= sizeof(printf_buf)) { - efi_puts("[Message truncated]\n"); - return -1; - } - - return printed; -} - -/* - * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi= +/** + * efi_parse_options() - Parse EFI command line options + * @cmdline: kernel command line + * + * Parse the ASCII string @cmdline for EFI options, denoted by the efi= * option, e.g. efi=nochunk. * * It should be noted that efi= is parsed in two very different * environments, first in the early boot environment of the EFI boot * stub, and subsequently during the kernel boot. + * + * Return: status code */ efi_status_t efi_parse_options(char const *cmdline) { - size_t len = strlen(cmdline) + 1; + char *buf __free(efi_pool) = NULL; efi_status_t status; - char *str, *buf; + size_t len; + char *str; + + if (!cmdline) + return EFI_SUCCESS; + len = strnlen(cmdline, COMMAND_LINE_SIZE - 1) + 1; status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, len, (void **)&buf); if (status != EFI_SUCCESS) return status; - str = skip_spaces(memcpy(buf, cmdline, len)); + memcpy(buf, cmdline, len - 1); + buf[len - 1] = '\0'; + str = skip_spaces(buf); while (*str) { char *param, *val; str = next_arg(str, ¶m, &val); + if (!val && !strcmp(param, "--")) + break; if (!strcmp(param, "nokaslr")) { efi_nokaslr = true; @@ -185,9 +77,17 @@ efi_status_t efi_parse_options(char const *cmdline) efi_loglevel = CONSOLE_LOGLEVEL_QUIET; } else if (!strcmp(param, "noinitrd")) { efi_noinitrd = true; + } else if (IS_ENABLED(CONFIG_X86_64) && !strcmp(param, "no5lvl")) { + efi_no5lvl = true; + } else if (IS_ENABLED(CONFIG_ARCH_HAS_MEM_ENCRYPT) && + !strcmp(param, "mem_encrypt") && val) { + if (parse_option_str(val, "on")) + efi_mem_encrypt = 1; + else if (parse_option_str(val, "off")) + efi_mem_encrypt = -1; } else if (!strcmp(param, "efi") && val) { efi_nochunk = parse_option_str(val, "nochunk"); - efi_novamap = parse_option_str(val, "novamap"); + efi_novamap |= parse_option_str(val, "novamap"); efi_nosoftreserve = IS_ENABLED(CONFIG_EFI_SOFT_RESERVE) && parse_option_str(val, "nosoftreserve"); @@ -203,29 +103,251 @@ efi_status_t efi_parse_options(char const *cmdline) efi_parse_option_graphics(val + strlen("efifb:")); } } - efi_bs_call(free_pool, buf); 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, u32 *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; +} + +enum efistub_event_type { + EFISTUB_EVT_INITRD, + EFISTUB_EVT_LOAD_OPTIONS, + EFISTUB_EVT_COUNT, +}; + +#define STR_WITH_SIZE(s) sizeof(s), s + +static const struct { + u32 pcr_index; + u32 event_id; + u32 event_data_len; + u8 event_data[52]; +} events[] = { + [EFISTUB_EVT_INITRD] = { + 9, + INITRD_EVENT_TAG_ID, + STR_WITH_SIZE("Linux initrd") + }, + [EFISTUB_EVT_LOAD_OPTIONS] = { + 9, + LOAD_OPTIONS_EVENT_TAG_ID, + STR_WITH_SIZE("LOADED_IMAGE::LoadOptions") + }, +}; + +static_assert(sizeof(efi_tcg2_event_t) == sizeof(efi_cc_event_t)); + +union efistub_event { + efi_tcg2_event_t tcg2_data; + efi_cc_event_t cc_data; +}; + +struct efistub_measured_event { + union efistub_event event_data; + TCG_PCClientTaggedEvent tagged_event __packed; +}; + +static efi_status_t efi_measure_tagged_event(unsigned long load_addr, + unsigned long load_size, + enum efistub_event_type event) +{ + union { + efi_status_t + (__efiapi *hash_log_extend_event)(void *, u64, efi_physical_addr_t, + u64, const union efistub_event *); + struct { u32 hash_log_extend_event; } mixed_mode; + } method; + struct efistub_measured_event *evt __free(efi_pool) = NULL; + int size = struct_size(evt, tagged_event.tagged_event_data, + events[event].event_data_len); + efi_guid_t tcg2_guid = EFI_TCG2_PROTOCOL_GUID; + efi_tcg2_protocol_t *tcg2 = NULL; + union efistub_event ev; + efi_status_t status; + void *protocol; + + efi_bs_call(locate_protocol, &tcg2_guid, NULL, (void **)&tcg2); + if (tcg2) { + ev.tcg2_data = (struct efi_tcg2_event){ + .event_size = size, + .event_header.header_size = sizeof(ev.tcg2_data.event_header), + .event_header.header_version = EFI_TCG2_EVENT_HEADER_VERSION, + .event_header.pcr_index = events[event].pcr_index, + .event_header.event_type = EV_EVENT_TAG, + }; + protocol = tcg2; + method.hash_log_extend_event = + (void *)efi_table_attr(tcg2, hash_log_extend_event); + } else { + efi_guid_t cc_guid = EFI_CC_MEASUREMENT_PROTOCOL_GUID; + efi_cc_protocol_t *cc = NULL; + + efi_bs_call(locate_protocol, &cc_guid, NULL, (void **)&cc); + if (!cc) + return EFI_UNSUPPORTED; + + ev.cc_data = (struct efi_cc_event){ + .event_size = size, + .event_header.header_size = sizeof(ev.cc_data.event_header), + .event_header.header_version = EFI_CC_EVENT_HEADER_VERSION, + .event_header.event_type = EV_EVENT_TAG, + }; + + status = efi_call_proto(cc, map_pcr_to_mr_index, + events[event].pcr_index, + &ev.cc_data.event_header.mr_index); + if (status != EFI_SUCCESS) + goto fail; + + protocol = cc; + method.hash_log_extend_event = + (void *)efi_table_attr(cc, hash_log_extend_event); + } + + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, size, (void **)&evt); + if (status != EFI_SUCCESS) + goto fail; + + *evt = (struct efistub_measured_event) { + .event_data = ev, + .tagged_event.tagged_event_id = events[event].event_id, + .tagged_event.tagged_event_data_size = events[event].event_data_len, + }; + + memcpy(evt->tagged_event.tagged_event_data, events[event].event_data, + events[event].event_data_len); + + status = efi_fn_call(&method, hash_log_extend_event, protocol, 0, + load_addr, load_size, &evt->event_data); + + if (status == EFI_SUCCESS) + return EFI_SUCCESS; + +fail: + efi_warn("Failed to measure data for event %d: 0x%lx\n", event, status); + return status; +} + +/* * Convert the unicode UEFI command line to ASCII to pass to kernel. * Size of memory allocated return in *cmd_line_len. * Returns NULL on error. */ -char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len) +char *efi_convert_cmdline(efi_loaded_image_t *image) { - const u16 *s2; - unsigned long cmdline_addr = 0; - int options_chars = efi_table_attr(image, load_options_size) / 2; - const u16 *options = efi_table_attr(image, load_options); + const efi_char16_t *options = efi_table_attr(image, load_options); + u32 options_size = efi_table_attr(image, load_options_size); int options_bytes = 0, safe_options_bytes = 0; /* UTF-8 bytes */ + unsigned long cmdline_addr = 0; + const efi_char16_t *s2; bool in_quote = false; efi_status_t status; + u32 options_chars; + + if (options_size > 0) + efi_measure_tagged_event((unsigned long)options, options_size, + EFISTUB_EVT_LOAD_OPTIONS); + + efi_apply_loadoptions_quirk((const void **)&options, &options_size); + options_chars = options_size / sizeof(efi_char16_t); if (options) { s2 = options; while (options_bytes < COMMAND_LINE_SIZE && options_chars--) { - u16 c = *s2++; + efi_char16_t c = *s2++; if (c < 0x80) { if (c == L'\0' || c == L'\n') @@ -282,38 +404,44 @@ char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len) snprintf((char *)cmdline_addr, options_bytes, "%.*ls", options_bytes - 1, options); - *cmd_line_len = options_bytes; return (char *)cmdline_addr; } -/* +/** + * efi_exit_boot_services() - Exit boot services + * @handle: handle of the exiting image + * @priv: argument to be passed to @priv_func + * @priv_func: function to process the memory map before exiting boot services + * * Handle calling ExitBootServices according to the requirements set out by the * spec. Obtains the current memory map, and returns that info after calling * ExitBootServices. The client must specify a function to perform any * processing of the memory map data prior to ExitBootServices. A client * specific structure may be passed to the function via priv. The client * function may be called multiple times. + * + * Return: status code */ -efi_status_t efi_exit_boot_services(void *handle, - struct efi_boot_memmap *map, - void *priv, +efi_status_t efi_exit_boot_services(void *handle, void *priv, efi_exit_boot_map_processing priv_func) { + struct efi_boot_memmap *map; efi_status_t status; - status = efi_get_memory_map(map); + if (efi_disable_pci_dma) + efi_pci_disable_bridge_busmaster(); + status = efi_get_memory_map(&map, true); if (status != EFI_SUCCESS) - goto fail; + return status; status = priv_func(map, priv); - if (status != EFI_SUCCESS) - goto free_map; - - if (efi_disable_pci_dma) - efi_pci_disable_bridge_busmaster(); + if (status != EFI_SUCCESS) { + efi_bs_call(free_pool, map); + return status; + } - status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); + status = efi_bs_call(exit_boot_services, handle, map->map_key); if (status == EFI_INVALID_PARAMETER) { /* @@ -329,38 +457,34 @@ efi_status_t efi_exit_boot_services(void *handle, * buffer should account for any changes in the map so the call * to get_memory_map() is expected to succeed here. */ - *map->map_size = *map->buff_size; + map->map_size = map->buff_size; status = efi_bs_call(get_memory_map, - map->map_size, - *map->map, - map->key_ptr, - map->desc_size, - map->desc_ver); + &map->map_size, + &map->map, + &map->map_key, + &map->desc_size, + &map->desc_ver); /* exit_boot_services() was called, thus cannot free */ if (status != EFI_SUCCESS) - goto fail; + return status; status = priv_func(map, priv); /* exit_boot_services() was called, thus cannot free */ if (status != EFI_SUCCESS) - goto fail; + return status; - status = efi_bs_call(exit_boot_services, handle, *map->key_ptr); + status = efi_bs_call(exit_boot_services, handle, map->map_key); } - /* exit_boot_services() was called, thus cannot free */ - if (status != EFI_SUCCESS) - goto fail; - - return EFI_SUCCESS; - -free_map: - efi_bs_call(free_pool, *map->map); -fail: return status; } +/** + * get_efi_config_table() - retrieve UEFI configuration table + * @guid: GUID of the configuration table to be retrieved + * Return: pointer to the configuration table or NULL + */ void *get_efi_config_table(efi_guid_t guid) { unsigned long tables = efi_table_attr(efi_system_table, tables); @@ -408,28 +532,25 @@ static const struct { }; /** - * efi_load_initrd_dev_path - load the initrd from the Linux initrd device path - * @load_addr: pointer to store the address where the initrd was loaded - * @load_size: pointer to store the size of the loaded initrd + * efi_load_initrd_dev_path() - load the initrd from the Linux initrd device path + * @initrd: pointer of struct to store the address where the initrd was loaded + * and the size of the loaded initrd * @max: upper limit for the initrd memory allocation - * @return: %EFI_SUCCESS if the initrd was loaded successfully, in which - * case @load_addr and @load_size are assigned accordingly - * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd - * device path - * %EFI_INVALID_PARAMETER if load_addr == NULL or load_size == NULL - * %EFI_OUT_OF_RESOURCES if memory allocation failed - * %EFI_LOAD_ERROR in all other cases + * + * Return: + * * %EFI_SUCCESS if the initrd was loaded successfully, in which + * case @load_addr and @load_size are assigned accordingly + * * %EFI_NOT_FOUND if no LoadFile2 protocol exists on the initrd device path + * * %EFI_OUT_OF_RESOURCES if memory allocation failed + * * %EFI_LOAD_ERROR in all other cases */ static -efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr, - unsigned long *load_size, +efi_status_t efi_load_initrd_dev_path(struct linux_efi_initrd *initrd, unsigned long max) { efi_guid_t lf2_proto_guid = EFI_LOAD_FILE2_PROTOCOL_GUID; efi_device_path_protocol_t *dp; efi_load_file2_protocol_t *lf2; - unsigned long initrd_addr; - unsigned long initrd_size; efi_handle_t handle; efi_status_t status; @@ -443,68 +564,111 @@ efi_status_t efi_load_initrd_dev_path(unsigned long *load_addr, if (status != EFI_SUCCESS) return status; - status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, NULL); + initrd->size = 0; + status = efi_call_proto(lf2, load_file, dp, false, &initrd->size, NULL); if (status != EFI_BUFFER_TOO_SMALL) return EFI_LOAD_ERROR; - status = efi_allocate_pages(initrd_size, &initrd_addr, max); + status = efi_allocate_pages(initrd->size, &initrd->base, max); if (status != EFI_SUCCESS) return status; - status = efi_call_proto(lf2, load_file, dp, false, &initrd_size, - (void *)initrd_addr); + status = efi_call_proto(lf2, load_file, dp, false, &initrd->size, + (void *)initrd->base); if (status != EFI_SUCCESS) { - efi_free(initrd_size, initrd_addr); + efi_free(initrd->size, initrd->base); return EFI_LOAD_ERROR; } - - *load_addr = initrd_addr; - *load_size = initrd_size; return EFI_SUCCESS; } static efi_status_t efi_load_initrd_cmdline(efi_loaded_image_t *image, - unsigned long *load_addr, - unsigned long *load_size, + struct linux_efi_initrd *initrd, unsigned long soft_limit, unsigned long hard_limit) { - if (!IS_ENABLED(CONFIG_EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER) || - (IS_ENABLED(CONFIG_X86) && (!efi_is_native() || image == NULL))) { - *load_addr = *load_size = 0; - return EFI_SUCCESS; - } + if (image == NULL) + return EFI_UNSUPPORTED; return handle_cmdline_files(image, L"initrd=", sizeof(L"initrd=") - 2, soft_limit, hard_limit, - load_addr, load_size); + &initrd->base, &initrd->size); } +/** + * efi_load_initrd() - Load initial RAM disk + * @image: EFI loaded image protocol + * @soft_limit: preferred address for loading the initrd + * @hard_limit: upper limit address for loading the initrd + * @out: pointer to store the address of the initrd table + * + * Return: status code + */ efi_status_t efi_load_initrd(efi_loaded_image_t *image, - unsigned long *load_addr, - unsigned long *load_size, unsigned long soft_limit, - unsigned long hard_limit) + unsigned long hard_limit, + const struct linux_efi_initrd **out) { - efi_status_t status; + efi_guid_t tbl_guid = LINUX_EFI_INITRD_MEDIA_GUID; + efi_status_t status = EFI_SUCCESS; + struct linux_efi_initrd initrd, *tbl; - if (!load_addr || !load_size) - return EFI_INVALID_PARAMETER; + if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD) || efi_noinitrd) + return EFI_SUCCESS; - status = efi_load_initrd_dev_path(load_addr, load_size, hard_limit); + status = efi_load_initrd_dev_path(&initrd, hard_limit); if (status == EFI_SUCCESS) { efi_info("Loaded initrd from LINUX_EFI_INITRD_MEDIA_GUID device path\n"); } else if (status == EFI_NOT_FOUND) { - status = efi_load_initrd_cmdline(image, load_addr, load_size, - soft_limit, hard_limit); - if (status == EFI_SUCCESS && *load_size > 0) + status = efi_load_initrd_cmdline(image, &initrd, soft_limit, + hard_limit); + /* command line loader disabled or no initrd= passed? */ + if (status == EFI_UNSUPPORTED || status == EFI_NOT_READY) + return EFI_SUCCESS; + if (status == EFI_SUCCESS) efi_info("Loaded initrd from command line option\n"); } + if (status != EFI_SUCCESS) + goto failed; + + if (initrd.size > 0 && + efi_measure_tagged_event(initrd.base, initrd.size, + EFISTUB_EVT_INITRD) == EFI_SUCCESS) + efi_info("Measured initrd data into PCR 9\n"); + + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, sizeof(initrd), + (void **)&tbl); + if (status != EFI_SUCCESS) + goto free_initrd; + + *tbl = initrd; + status = efi_bs_call(install_configuration_table, &tbl_guid, tbl); + if (status != EFI_SUCCESS) + goto free_tbl; + + if (out) + *out = tbl; + return EFI_SUCCESS; +free_tbl: + efi_bs_call(free_pool, tbl); +free_initrd: + efi_free(initrd.size, initrd.base); +failed: + efi_err("Failed to load initrd: 0x%lx\n", status); return status; } +/** + * efi_wait_for_key() - Wait for key stroke + * @usec: number of microseconds to wait for key stroke + * @key: key entered + * + * Wait for up to @usec microseconds for a key stroke. + * + * Return: status code, EFI_SUCCESS if key received + */ efi_status_t efi_wait_for_key(unsigned long usec, efi_input_key_t *key) { efi_event_t events[2], timer; @@ -539,3 +703,70 @@ efi_status_t efi_wait_for_key(unsigned long usec, efi_input_key_t *key) return status; } + +/** + * efi_remap_image - Remap a loaded image with the appropriate permissions + * for code and data + * + * @image_base: the base of the image in memory + * @alloc_size: the size of the area in memory occupied by the image + * @code_size: the size of the leading part of the image containing code + * and read-only data + * + * efi_remap_image() uses the EFI memory attribute protocol to remap the code + * region of the loaded image read-only/executable, and the remainder + * read-write/non-executable. The code region is assumed to start at the base + * of the image, and will therefore cover the PE/COFF header as well. + */ +void efi_remap_image(unsigned long image_base, unsigned alloc_size, + unsigned long code_size) +{ + efi_guid_t guid = EFI_MEMORY_ATTRIBUTE_PROTOCOL_GUID; + efi_memory_attribute_protocol_t *memattr; + efi_status_t status; + u64 attr; + + /* + * If the firmware implements the EFI_MEMORY_ATTRIBUTE_PROTOCOL, let's + * invoke it to remap the text/rodata region of the decompressed image + * as read-only and the data/bss region as non-executable. + */ + status = efi_bs_call(locate_protocol, &guid, NULL, (void **)&memattr); + if (status != EFI_SUCCESS) + return; + + // Get the current attributes for the entire region + status = memattr->get_memory_attributes(memattr, image_base, + alloc_size, &attr); + if (status != EFI_SUCCESS) { + efi_warn("Failed to retrieve memory attributes for image region: 0x%lx\n", + status); + return; + } + + // Mark the code region as read-only + status = memattr->set_memory_attributes(memattr, image_base, code_size, + EFI_MEMORY_RO); + if (status != EFI_SUCCESS) { + efi_warn("Failed to remap code region read-only\n"); + return; + } + + // If the entire region was already mapped as non-exec, clear the + // attribute from the code region. Otherwise, set it on the data + // region. + if (attr & EFI_MEMORY_XP) { + status = memattr->clear_memory_attributes(memattr, image_base, + code_size, + EFI_MEMORY_XP); + if (status != EFI_SUCCESS) + efi_warn("Failed to remap code region executable\n"); + } else { + status = memattr->set_memory_attributes(memattr, + image_base + code_size, + alloc_size - code_size, + EFI_MEMORY_XP); + if (status != EFI_SUCCESS) + efi_warn("Failed to remap data region non-executable\n"); + } +} |
