diff options
Diffstat (limited to 'drivers/firmware/efi/libstub')
| -rw-r--r-- | drivers/firmware/efi/libstub/Makefile | 3 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/arm-stub.c | 3 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/arm64-stub.c | 16 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/efi-stub-helper.c | 4 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/random.c | 10 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/tpm.c | 58 |
6 files changed, 82 insertions, 12 deletions
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 37e24f525162..dedf9bde44db 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -10,7 +10,7 @@ cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ -O2 \ -fPIC -fno-strict-aliasing -mno-red-zone \ -mno-mmx -mno-sse -cflags-$(CONFIG_ARM64) := $(subst -pg,,$(KBUILD_CFLAGS)) +cflags-$(CONFIG_ARM64) := $(subst -pg,,$(KBUILD_CFLAGS)) -fpie cflags-$(CONFIG_ARM) := $(subst -pg,,$(KBUILD_CFLAGS)) \ -fno-builtin -fpic -mno-single-pic-base @@ -30,6 +30,7 @@ OBJECT_FILES_NON_STANDARD := y KCOV_INSTRUMENT := n lib-y := efi-stub-helper.o gop.o secureboot.o +lib-$(CONFIG_RESET_ATTACK_MITIGATION) += tpm.o # include the stub's generic dependencies from lib/ when building for ARM/arm64 arm-deps := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c sort.c diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 8181ac179d14..1cb2d1c070c3 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -192,6 +192,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, goto fail_free_cmdline; } + /* Ask the firmware to clear memory on unclean shutdown */ + efi_enable_reset_attack_mitigation(sys_table); + secure_boot = efi_get_secureboot(sys_table); /* diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index b4c2589d7c91..b9bd827caa22 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -9,9 +9,18 @@ * published by the Free Software Foundation. * */ + +/* + * To prevent the compiler from emitting GOT-indirected (and thus absolute) + * references to the section markers, override their visibility as 'hidden' + */ +#pragma GCC visibility push(hidden) +#include <asm/sections.h> +#pragma GCC visibility pop + #include <linux/efi.h> #include <asm/efi.h> -#include <asm/sections.h> +#include <asm/memory.h> #include <asm/sysreg.h> #include "efistub.h" @@ -81,9 +90,10 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg, /* * If CONFIG_DEBUG_ALIGN_RODATA is not set, produce a * displacement in the interval [0, MIN_KIMG_ALIGN) that - * is a multiple of the minimal segment alignment (SZ_64K) + * doesn't violate this kernel's de-facto alignment + * constraints. */ - u32 mask = (MIN_KIMG_ALIGN - 1) & ~(SZ_64K - 1); + u32 mask = (MIN_KIMG_ALIGN - 1) & ~(EFI_KIMG_ALIGN - 1); u32 offset = !IS_ENABLED(CONFIG_DEBUG_ALIGN_RODATA) ? (phys_seed >> 32) & mask : TEXT_OFFSET; diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index b0184360efc6..50a9cab5a834 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -205,7 +205,7 @@ again: unsigned long m = (unsigned long)map; u64 start, end; - desc = (efi_memory_desc_t *)(m + (i * desc_size)); + desc = efi_early_memdesc_ptr(m, desc_size, i); if (desc->type != EFI_CONVENTIONAL_MEMORY) continue; @@ -298,7 +298,7 @@ efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg, unsigned long m = (unsigned long)map; u64 start, end; - desc = (efi_memory_desc_t *)(m + (i * desc_size)); + desc = efi_early_memdesc_ptr(m, desc_size, i); if (desc->type != EFI_CONVENTIONAL_MEMORY) continue; diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c index 7e72954d5860..e0e603a89aa9 100644 --- a/drivers/firmware/efi/libstub/random.c +++ b/drivers/firmware/efi/libstub/random.c @@ -145,8 +145,6 @@ efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg, return status; } -#define RANDOM_SEED_SIZE 32 - efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg) { efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID; @@ -162,25 +160,25 @@ efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg) return status; status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA, - sizeof(*seed) + RANDOM_SEED_SIZE, + sizeof(*seed) + EFI_RANDOM_SEED_SIZE, (void **)&seed); if (status != EFI_SUCCESS) return status; - status = rng->get_rng(rng, &rng_algo_raw, RANDOM_SEED_SIZE, + status = rng->get_rng(rng, &rng_algo_raw, EFI_RANDOM_SEED_SIZE, seed->bits); if (status == EFI_UNSUPPORTED) /* * Use whatever algorithm we have available if the raw algorithm * is not implemented. */ - status = rng->get_rng(rng, NULL, RANDOM_SEED_SIZE, + status = rng->get_rng(rng, NULL, EFI_RANDOM_SEED_SIZE, seed->bits); if (status != EFI_SUCCESS) goto err_freepool; - seed->size = RANDOM_SEED_SIZE; + seed->size = EFI_RANDOM_SEED_SIZE; status = efi_call_early(install_configuration_table, &rng_table_guid, seed); if (status != EFI_SUCCESS) diff --git a/drivers/firmware/efi/libstub/tpm.c b/drivers/firmware/efi/libstub/tpm.c new file mode 100644 index 000000000000..6224cdbc9669 --- /dev/null +++ b/drivers/firmware/efi/libstub/tpm.c @@ -0,0 +1,58 @@ +/* + * TPM handling. + * + * Copyright (C) 2016 CoreOS, Inc + * Copyright (C) 2017 Google, Inc. + * Matthew Garrett <mjg59@google.com> + * + * This file is part of the Linux kernel, and is made available under the + * terms of the GNU General Public License version 2. + */ +#include <linux/efi.h> +#include <asm/efi.h> + +#include "efistub.h" + +static const efi_char16_t efi_MemoryOverWriteRequest_name[] = { + 'M', 'e', 'm', 'o', 'r', 'y', 'O', 'v', 'e', 'r', 'w', 'r', 'i', 't', + 'e', 'R', 'e', 'q', 'u', 'e', 's', 't', 'C', 'o', 'n', 't', 'r', 'o', + 'l', 0 +}; + +#define MEMORY_ONLY_RESET_CONTROL_GUID \ + EFI_GUID(0xe20939be, 0x32d4, 0x41be, 0xa1, 0x50, 0x89, 0x7f, 0x85, 0xd4, 0x98, 0x29) + +#define get_efi_var(name, vendor, ...) \ + efi_call_runtime(get_variable, \ + (efi_char16_t *)(name), (efi_guid_t *)(vendor), \ + __VA_ARGS__) + +#define set_efi_var(name, vendor, ...) \ + efi_call_runtime(set_variable, \ + (efi_char16_t *)(name), (efi_guid_t *)(vendor), \ + __VA_ARGS__) + +/* + * Enable reboot attack mitigation. This requests that the firmware clear the + * RAM on next reboot before proceeding with boot, ensuring that any secrets + * are cleared. If userland has ensured that all secrets have been removed + * from RAM before reboot it can simply reset this variable. + */ +void efi_enable_reset_attack_mitigation(efi_system_table_t *sys_table_arg) +{ + u8 val = 1; + efi_guid_t var_guid = MEMORY_ONLY_RESET_CONTROL_GUID; + efi_status_t status; + unsigned long datasize = 0; + + status = get_efi_var(efi_MemoryOverWriteRequest_name, &var_guid, + NULL, &datasize, NULL); + + if (status == EFI_NOT_FOUND) + return; + + set_efi_var(efi_MemoryOverWriteRequest_name, &var_guid, + EFI_VARIABLE_NON_VOLATILE | + EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_RUNTIME_ACCESS, sizeof(val), &val); +} |