diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-23 11:27:24 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-23 11:27:24 -0700 |
commit | bf2431021c8cfe52c866d7bf640ced03a35ebe91 (patch) | |
tree | 7c63eeabd3adb2883629c18ca351bcdb534a824b /drivers/firmware | |
parent | 4b0986a3613c92f4ec1bdc7f60ec66fea135991f (diff) | |
parent | 3f68e69520d3d52d66a6ad872a75b7d8f2ea7665 (diff) |
Merge tag 'efi-next-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi
Pull EFI updates from Ard Biesheuvel:
- Allow runtime services to be re-enabled at boot on RT kernels.
- Provide access to secrets injected into the boot image by CoCo
hypervisors (COnfidential COmputing)
- Use DXE services on x86 to make the boot image executable after
relocation, if needed.
- Prefer mirrored memory for randomized allocations.
- Only randomize the placement of the kernel image on arm64 if the
loader has not already done so.
- Add support for obtaining the boot hartid from EFI on RISC-V.
* tag 'efi-next-for-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
riscv/efi_stub: Add support for RISCV_EFI_BOOT_PROTOCOL
efi: stub: prefer mirrored memory for randomized allocations
efi/arm64: libstub: run image in place if randomized by the loader
efi: libstub: pass image handle to handle_kernel_image()
efi: x86: Set the NX-compatibility flag in the PE header
efi: libstub: ensure allocated memory to be executable
efi: libstub: declare DXE services table
efi: Add missing prototype for efi_capsule_setup_info
docs: security: Add secrets/coco documentation
efi: Register efi_secret platform device if EFI secret area is declared
virt: Add efi_secret module to expose confidential computing secrets
efi: Save location of EFI confidential computing area
efi: Allow to enable EFI runtime services by default on RT
Diffstat (limited to 'drivers/firmware')
-rw-r--r-- | drivers/firmware/efi/Kconfig | 43 | ||||
-rw-r--r-- | drivers/firmware/efi/efi.c | 13 | ||||
-rw-r--r-- | drivers/firmware/efi/libstub/arm32-stub.c | 3 | ||||
-rw-r--r-- | drivers/firmware/efi/libstub/arm64-stub.c | 15 | ||||
-rw-r--r-- | drivers/firmware/efi/libstub/efi-stub.c | 2 | ||||
-rw-r--r-- | drivers/firmware/efi/libstub/efistub.h | 84 | ||||
-rw-r--r-- | drivers/firmware/efi/libstub/randomalloc.c | 11 | ||||
-rw-r--r-- | drivers/firmware/efi/libstub/riscv-stub.c | 32 | ||||
-rw-r--r-- | drivers/firmware/efi/libstub/x86-stub.c | 119 |
9 files changed, 302 insertions, 20 deletions
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index 2c3dac5ecb36..4720ba98cec3 100644 --- a/drivers/firmware/efi/Kconfig +++ b/drivers/firmware/efi/Kconfig @@ -91,6 +91,18 @@ config EFI_SOFT_RESERVE If unsure, say Y. +config EFI_DXE_MEM_ATTRIBUTES + bool "Adjust memory attributes in EFISTUB" + depends on EFI && EFI_STUB && X86 + default y + help + UEFI specification does not guarantee all memory to be + accessible for both write and execute as the kernel expects + it to be. + Use DXE services to check and alter memory protection + attributes during boot via EFISTUB to ensure that memory + ranges used by the kernel are writable and executable. + config EFI_PARAMS_FROM_FDT bool help @@ -284,3 +296,34 @@ config EFI_CUSTOM_SSDT_OVERLAYS See Documentation/admin-guide/acpi/ssdt-overlays.rst for more information. + +config EFI_DISABLE_RUNTIME + bool "Disable EFI runtime services support by default" + default y if PREEMPT_RT + help + Allow to disable the EFI runtime services support by default. This can + already be achieved by using the efi=noruntime option, but it could be + useful to have this default without any kernel command line parameter. + + The EFI runtime services are disabled by default when PREEMPT_RT is + enabled, because measurements have shown that some EFI functions calls + might take too much time to complete, causing large latencies which is + an issue for Real-Time kernels. + + This default can be overridden by using the efi=runtime option. + +config EFI_COCO_SECRET + bool "EFI Confidential Computing Secret Area Support" + depends on EFI + help + Confidential Computing platforms (such as AMD SEV) allow the + Guest Owner to securely inject secrets during guest VM launch. + The secrets are placed in a designated EFI reserved memory area. + + In order to use the secrets in the kernel, the location of the secret + area (as published in the EFI config table) must be kept. + + If you say Y here, the address of the EFI secret area will be kept + for usage inside the kernel. This will allow the + virt/coco/efi_secret module to access the secrets, which in turn + allows userspace programs to access the injected secrets. diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 5502e176d51b..860534bcfdac 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -46,6 +46,9 @@ struct efi __read_mostly efi = { #ifdef CONFIG_LOAD_UEFI_KEYS .mokvar_table = EFI_INVALID_TABLE_ADDR, #endif +#ifdef CONFIG_EFI_COCO_SECRET + .coco_secret = EFI_INVALID_TABLE_ADDR, +#endif }; EXPORT_SYMBOL(efi); @@ -66,7 +69,7 @@ struct mm_struct efi_mm = { struct workqueue_struct *efi_rts_wq; -static bool disable_runtime = IS_ENABLED(CONFIG_PREEMPT_RT); +static bool disable_runtime = IS_ENABLED(CONFIG_EFI_DISABLE_RUNTIME); static int __init setup_noefi(char *arg) { disable_runtime = true; @@ -422,6 +425,11 @@ static int __init efisubsys_init(void) if (efi_enabled(EFI_DBG) && efi_enabled(EFI_PRESERVE_BS_REGIONS)) efi_debugfs_init(); +#ifdef CONFIG_EFI_COCO_SECRET + if (efi.coco_secret != EFI_INVALID_TABLE_ADDR) + platform_device_register_simple("efi_secret", 0, NULL, 0); +#endif + return 0; err_remove_group: @@ -529,6 +537,9 @@ static const efi_config_table_type_t common_tables[] __initconst = { #ifdef CONFIG_LOAD_UEFI_KEYS {LINUX_EFI_MOK_VARIABLE_TABLE_GUID, &efi.mokvar_table, "MOKvar" }, #endif +#ifdef CONFIG_EFI_COCO_SECRET + {LINUX_EFI_COCO_SECRET_AREA_GUID, &efi.coco_secret, "CocoSecret" }, +#endif {}, }; diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c index 4b5b2403b3a0..0131e3aaa605 100644 --- a/drivers/firmware/efi/libstub/arm32-stub.c +++ b/drivers/firmware/efi/libstub/arm32-stub.c @@ -117,7 +117,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long *image_size, unsigned long *reserve_addr, unsigned long *reserve_size, - efi_loaded_image_t *image) + efi_loaded_image_t *image, + efi_handle_t image_handle) { const int slack = TEXT_OFFSET - 5 * PAGE_SIZE; int alloc_size = MAX_UNCOMP_KERNEL_SIZE + EFI_PHYS_ALIGN; diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index 9cc556013d08..577173ee1f83 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -83,7 +83,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long *image_size, unsigned long *reserve_addr, unsigned long *reserve_size, - efi_loaded_image_t *image) + efi_loaded_image_t *image, + efi_handle_t image_handle) { efi_status_t status; unsigned long kernel_size, kernel_memsize = 0; @@ -100,7 +101,15 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, u64 min_kimg_align = efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN; if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { - if (!efi_nokaslr) { + efi_guid_t li_fixed_proto = LINUX_EFI_LOADED_IMAGE_FIXED_GUID; + void *p; + + if (efi_nokaslr) { + efi_info("KASLR disabled on kernel command line\n"); + } else if (efi_bs_call(handle_protocol, image_handle, + &li_fixed_proto, &p) == EFI_SUCCESS) { + efi_info("Image placement fixed by loader\n"); + } else { status = efi_get_random_bytes(sizeof(phys_seed), (u8 *)&phys_seed); if (status == EFI_NOT_FOUND) { @@ -111,8 +120,6 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, status); efi_nokaslr = true; } - } else { - efi_info("KASLR disabled on kernel command line\n"); } } diff --git a/drivers/firmware/efi/libstub/efi-stub.c b/drivers/firmware/efi/libstub/efi-stub.c index da93864d7abc..f515394cce6e 100644 --- a/drivers/firmware/efi/libstub/efi-stub.c +++ b/drivers/firmware/efi/libstub/efi-stub.c @@ -198,7 +198,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, status = handle_kernel_image(&image_addr, &image_size, &reserve_addr, &reserve_size, - image); + image, handle); if (status != EFI_SUCCESS) { efi_err("Failed to relocate kernel\n"); goto fail_free_screeninfo; diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index edb77b0621ea..b0ae0a454404 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -36,6 +36,9 @@ extern bool efi_novamap; extern const efi_system_table_t *efi_system_table; +typedef union efi_dxe_services_table efi_dxe_services_table_t; +extern const efi_dxe_services_table_t *efi_dxe_table; + efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg); @@ -44,6 +47,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, #define efi_is_native() (true) #define efi_bs_call(func, ...) efi_system_table->boottime->func(__VA_ARGS__) #define efi_rt_call(func, ...) efi_system_table->runtime->func(__VA_ARGS__) +#define efi_dxe_call(func, ...) efi_dxe_table->func(__VA_ARGS__) #define efi_table_attr(inst, attr) (inst->attr) #define efi_call_proto(inst, func, ...) inst->func(inst, ##__VA_ARGS__) @@ -329,6 +333,76 @@ union efi_boot_services { } mixed_mode; }; +typedef enum { + EfiGcdMemoryTypeNonExistent, + EfiGcdMemoryTypeReserved, + EfiGcdMemoryTypeSystemMemory, + EfiGcdMemoryTypeMemoryMappedIo, + EfiGcdMemoryTypePersistent, + EfiGcdMemoryTypeMoreReliable, + EfiGcdMemoryTypeMaximum +} efi_gcd_memory_type_t; + +typedef struct { + efi_physical_addr_t base_address; + u64 length; + u64 capabilities; + u64 attributes; + efi_gcd_memory_type_t gcd_memory_type; + void *image_handle; + void *device_handle; +} efi_gcd_memory_space_desc_t; + +/* + * EFI DXE Services table + */ +union efi_dxe_services_table { + struct { + efi_table_hdr_t hdr; + void *add_memory_space; + void *allocate_memory_space; + void *free_memory_space; + void *remove_memory_space; + efi_status_t (__efiapi *get_memory_space_descriptor)(efi_physical_addr_t, + efi_gcd_memory_space_desc_t *); + efi_status_t (__efiapi *set_memory_space_attributes)(efi_physical_addr_t, + u64, u64); + void *get_memory_space_map; + void *add_io_space; + void *allocate_io_space; + void *free_io_space; + void *remove_io_space; + void *get_io_space_descriptor; + void *get_io_space_map; + void *dispatch; + void *schedule; + void *trust; + void *process_firmware_volume; + void *set_memory_space_capabilities; + }; + struct { + efi_table_hdr_t hdr; + u32 add_memory_space; + u32 allocate_memory_space; + u32 free_memory_space; + u32 remove_memory_space; + u32 get_memory_space_descriptor; + u32 set_memory_space_attributes; + u32 get_memory_space_map; + u32 add_io_space; + u32 allocate_io_space; + u32 free_io_space; + u32 remove_io_space; + u32 get_io_space_descriptor; + u32 get_io_space_map; + u32 dispatch; + u32 schedule; + u32 trust; + u32 process_firmware_volume; + u32 set_memory_space_capabilities; + } mixed_mode; +}; + typedef union efi_uga_draw_protocol efi_uga_draw_protocol_t; union efi_uga_draw_protocol { @@ -720,6 +794,13 @@ union efi_tcg2_protocol { } mixed_mode; }; +struct riscv_efi_boot_protocol { + u64 revision; + + efi_status_t (__efiapi *get_boot_hartid)(struct riscv_efi_boot_protocol *, + unsigned long *boot_hartid); +}; + typedef union efi_load_file_protocol efi_load_file_protocol_t; typedef union efi_load_file_protocol efi_load_file2_protocol_t; @@ -865,7 +946,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long *image_size, unsigned long *reserve_addr, unsigned long *reserve_size, - efi_loaded_image_t *image); + efi_loaded_image_t *image, + efi_handle_t image_handle); asmlinkage void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt_addr, diff --git a/drivers/firmware/efi/libstub/randomalloc.c b/drivers/firmware/efi/libstub/randomalloc.c index 724155b9e10d..715f37479154 100644 --- a/drivers/firmware/efi/libstub/randomalloc.c +++ b/drivers/firmware/efi/libstub/randomalloc.c @@ -56,6 +56,7 @@ efi_status_t efi_random_alloc(unsigned long size, unsigned long random_seed) { unsigned long map_size, desc_size, total_slots = 0, target_slot; + unsigned long total_mirrored_slots = 0; unsigned long buff_size; efi_status_t status; efi_memory_desc_t *memory_map; @@ -86,8 +87,14 @@ efi_status_t efi_random_alloc(unsigned long size, slots = get_entry_num_slots(md, size, ilog2(align)); MD_NUM_SLOTS(md) = slots; total_slots += slots; + if (md->attribute & EFI_MEMORY_MORE_RELIABLE) + total_mirrored_slots += slots; } + /* consider only mirrored slots for randomization if any exist */ + if (total_mirrored_slots > 0) + total_slots = total_mirrored_slots; + /* find a random number between 0 and total_slots */ target_slot = (total_slots * (u64)(random_seed & U32_MAX)) >> 32; @@ -107,6 +114,10 @@ efi_status_t efi_random_alloc(unsigned long size, efi_physical_addr_t target; unsigned long pages; + if (total_mirrored_slots > 0 && + !(md->attribute & EFI_MEMORY_MORE_RELIABLE)) + continue; + if (target_slot >= MD_NUM_SLOTS(md)) { target_slot -= MD_NUM_SLOTS(md); continue; diff --git a/drivers/firmware/efi/libstub/riscv-stub.c b/drivers/firmware/efi/libstub/riscv-stub.c index 9c460843442f..9e85e58d1f27 100644 --- a/drivers/firmware/efi/libstub/riscv-stub.c +++ b/drivers/firmware/efi/libstub/riscv-stub.c @@ -21,9 +21,9 @@ #define MIN_KIMG_ALIGN SZ_4M #endif -typedef void __noreturn (*jump_kernel_func)(unsigned int, unsigned long); +typedef void __noreturn (*jump_kernel_func)(unsigned long, unsigned long); -static u32 hartid; +static unsigned long hartid; static int get_boot_hartid_from_fdt(void) { @@ -47,14 +47,31 @@ static int get_boot_hartid_from_fdt(void) return 0; } +static efi_status_t get_boot_hartid_from_efi(void) +{ + efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID; + struct riscv_efi_boot_protocol *boot_protocol; + efi_status_t status; + + status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL, + (void **)&boot_protocol); + if (status != EFI_SUCCESS) + return status; + return efi_call_proto(boot_protocol, get_boot_hartid, &hartid); +} + efi_status_t check_platform_features(void) { + efi_status_t status; int ret; - ret = get_boot_hartid_from_fdt(); - if (ret) { - efi_err("/chosen/boot-hartid missing or invalid!\n"); - return EFI_UNSUPPORTED; + status = get_boot_hartid_from_efi(); + if (status != EFI_SUCCESS) { + ret = get_boot_hartid_from_fdt(); + if (ret) { + efi_err("Failed to get boot hartid!\n"); + return EFI_UNSUPPORTED; + } } return EFI_SUCCESS; } @@ -80,7 +97,8 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, unsigned long *image_size, unsigned long *reserve_addr, unsigned long *reserve_size, - efi_loaded_image_t *image) + efi_loaded_image_t *image, + efi_handle_t image_handle) { unsigned long kernel_size = 0; unsigned long preferred_addr; diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index 01ddd4502e28..b14e88ccefca 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -22,6 +22,7 @@ #define MAXMEM_X86_64_4LEVEL (1ull << 46) const efi_system_table_t *efi_system_table; +const efi_dxe_services_table_t *efi_dxe_table; extern u32 image_offset; static efi_loaded_image_t *image = NULL; @@ -211,9 +212,110 @@ static void retrieve_apple_device_properties(struct boot_params *boot_params) } } +static void +adjust_memory_range_protection(unsigned long start, unsigned long size) +{ + efi_status_t status; + efi_gcd_memory_space_desc_t desc; + unsigned long end, next; + unsigned long rounded_start, rounded_end; + unsigned long unprotect_start, unprotect_size; + int has_system_memory = 0; + + if (efi_dxe_table == NULL) + return; + + rounded_start = rounddown(start, EFI_PAGE_SIZE); + rounded_end = roundup(start + size, EFI_PAGE_SIZE); + + /* + * Don't modify memory region attributes, they are + * already suitable, to lower the possibility to + * encounter firmware bugs. + */ + + for (end = start + size; start < end; start = next) { + + status = efi_dxe_call(get_memory_space_descriptor, start, &desc); + + if (status != EFI_SUCCESS) + return; + + next = desc.base_address + desc.length; + + /* + * Only system memory is suitable for trampoline/kernel image placement, + * so only this type of memory needs its attributes to be modified. + */ + + if (desc.gcd_memory_type != EfiGcdMemoryTypeSystemMemory || + (desc.attributes & (EFI_MEMORY_RO | EFI_MEMORY_XP)) == 0) + continue; + + unprotect_start = max(rounded_start, (unsigned long)desc.base_address); + unprotect_size = min(rounded_end, next) - unprotect_start; + + status = efi_dxe_call(set_memory_space_attributes, + unprotect_start, unprotect_size, + EFI_MEMORY_WB); + + if (status != EFI_SUCCESS) { + efi_warn("Unable to unprotect memory range [%08lx,%08lx]: %d\n", + unprotect_start, + unprotect_start + unprotect_size, + (int)status); + } + } +} + +/* + * Trampoline takes 2 pages and can be loaded in first megabyte of memory + * with its end placed between 128k and 640k where BIOS might start. + * (see arch/x86/boot/compressed/pgtable_64.c) + * + * We cannot find exact trampoline placement since memory map + * can be modified by UEFI, and it can alter the computed address. + */ + +#define TRAMPOLINE_PLACEMENT_BASE ((128 - 8)*1024) +#define TRAMPOLINE_PLACEMENT_SIZE (640*1024 - (128 - 8)*1024) + +void startup_32(struct boot_params *boot_params); + +static void +setup_memory_protection(unsigned long image_base, unsigned long image_size) +{ + /* + * Allow execution of possible trampoline used + * for switching between 4- and 5-level page tables + * and relocated kernel image. + */ + + adjust_memory_range_protection(TRAMPOLINE_PLACEMENT_BASE, + TRAMPOLINE_PLACEMENT_SIZE); + +#ifdef CONFIG_64BIT + if (image_base != (unsigned long)startup_32) + adjust_memory_range_protection(image_base, image_size); +#else + /* + * Clear protection flags on a whole range of possible + * addresses used for KASLR. We don't need to do that + * on x86_64, since KASLR/extraction is performed after + * dedicated identity page tables are built and we only + * need to remove possible protection on relocated image + * itself disregarding further relocations. + */ + adjust_memory_range_protection(LOAD_PHYSICAL_ADDR, + KERNEL_IMAGE_SIZE - LOAD_PHYSICAL_ADDR); +#endif +} + static const efi_char16_t apple[] = L"Apple"; -static void setup_quirks(struct boot_params *boot_params) +static void setup_quirks(struct boot_params *boot_params, + unsigned long image_base, + unsigned long image_size) { efi_char16_t *fw_vendor = (efi_char16_t *)(unsigned long) efi_table_attr(efi_system_table, fw_vendor); @@ -222,6 +324,9 @@ static void setup_quirks(struct boot_params *boot_params) if (IS_ENABLED(CONFIG_APPLE_PROPERTIES)) retrieve_apple_device_properties(boot_params); } + + if (IS_ENABLED(CONFIG_EFI_DXE_MEM_ATTRIBUTES)) + setup_memory_protection(image_base, image_size); } /* @@ -341,8 +446,6 @@ static void __noreturn efi_exit(efi_handle_t handle, efi_status_t status) asm("hlt"); } -void startup_32(struct boot_params *boot_params); - void __noreturn efi_stub_entry(efi_handle_t handle, efi_system_table_t *sys_table_arg, struct boot_params *boot_params); @@ -677,11 +780,17 @@ unsigned long efi_main(efi_handle_t handle, efi_status_t status; efi_system_table = sys_table_arg; - /* Check if we were booted by the EFI firmware */ if (efi_system_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE) efi_exit(handle, EFI_INVALID_PARAMETER); + efi_dxe_table = get_efi_config_table(EFI_DXE_SERVICES_TABLE_GUID); + if (efi_dxe_table && + efi_dxe_table->hdr.signature != EFI_DXE_SERVICES_TABLE_SIGNATURE) { + efi_warn("Ignoring DXE services table: invalid signature\n"); + efi_dxe_table = NULL; + } + /* * If the kernel isn't already loaded at a suitable address, * relocate it. @@ -791,7 +900,7 @@ unsigned long efi_main(efi_handle_t handle, setup_efi_pci(boot_params); - setup_quirks(boot_params); + setup_quirks(boot_params, bzimage_addr, buffer_end - buffer_start); status = exit_boot(boot_params, handle); if (status != EFI_SUCCESS) { |