diff options
Diffstat (limited to 'drivers/firmware')
| -rw-r--r-- | drivers/firmware/efi/libstub/Makefile | 7 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/arm-stub.c | 40 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/arm64-stub.c | 87 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/efi-stub-helper.c | 7 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/efistub.h | 7 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/fdt.c | 14 | ||||
| -rw-r--r-- | drivers/firmware/efi/libstub/random.c | 135 |
7 files changed, 258 insertions, 39 deletions
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile index 3c0467d3688c..c4098748e1fe 100644 --- a/drivers/firmware/efi/libstub/Makefile +++ b/drivers/firmware/efi/libstub/Makefile @@ -8,7 +8,7 @@ cflags-$(CONFIG_X86_32) := -march=i386 cflags-$(CONFIG_X86_64) := -mcmodel=small cflags-$(CONFIG_X86) += -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2 \ -fPIC -fno-strict-aliasing -mno-red-zone \ - -mno-mmx -mno-sse -DDISABLE_BRANCH_PROFILING + -mno-mmx -mno-sse cflags-$(CONFIG_ARM64) := $(subst -pg,,$(KBUILD_CFLAGS)) cflags-$(CONFIG_ARM) := $(subst -pg,,$(KBUILD_CFLAGS)) \ @@ -16,7 +16,7 @@ cflags-$(CONFIG_ARM) := $(subst -pg,,$(KBUILD_CFLAGS)) \ cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt -KBUILD_CFLAGS := $(cflags-y) \ +KBUILD_CFLAGS := $(cflags-y) -DDISABLE_BRANCH_PROFILING \ $(call cc-option,-ffreestanding) \ $(call cc-option,-fno-stack-protector) @@ -34,7 +34,8 @@ $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \ $(patsubst %.c,lib-%.o,$(arm-deps)) -lib-$(CONFIG_ARM64) += arm64-stub.o +lib-$(CONFIG_ARM) += arm32-stub.o +lib-$(CONFIG_ARM64) += arm64-stub.o random.o CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) # diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 950c87f5d279..d5aa1d16154f 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -18,6 +18,8 @@ #include "efistub.h" +bool __nokaslr; + static int efi_secureboot_enabled(efi_system_table_t *sys_table_arg) { static efi_guid_t const var_guid = EFI_GLOBAL_VARIABLE_GUID; @@ -207,14 +209,6 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, pr_efi_err(sys_table, "Failed to find DRAM base\n"); goto fail; } - status = handle_kernel_image(sys_table, image_addr, &image_size, - &reserve_addr, - &reserve_size, - dram_base, image); - if (status != EFI_SUCCESS) { - pr_efi_err(sys_table, "Failed to relocate kernel\n"); - goto fail; - } /* * Get the command line from EFI, using the LOADED_IMAGE @@ -224,7 +218,28 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size); if (!cmdline_ptr) { pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n"); - goto fail_free_image; + goto fail; + } + + /* check whether 'nokaslr' was passed on the command line */ + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { + static const u8 default_cmdline[] = CONFIG_CMDLINE; + const u8 *str, *cmdline = cmdline_ptr; + + if (IS_ENABLED(CONFIG_CMDLINE_FORCE)) + cmdline = default_cmdline; + str = strstr(cmdline, "nokaslr"); + if (str == cmdline || (str > cmdline && *(str - 1) == ' ')) + __nokaslr = true; + } + + status = handle_kernel_image(sys_table, image_addr, &image_size, + &reserve_addr, + &reserve_size, + dram_base, image); + if (status != EFI_SUCCESS) { + pr_efi_err(sys_table, "Failed to relocate kernel\n"); + goto fail_free_cmdline; } status = efi_parse_options(cmdline_ptr); @@ -244,7 +259,7 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, if (status != EFI_SUCCESS) { pr_efi_err(sys_table, "Failed to load device tree!\n"); - goto fail_free_cmdline; + goto fail_free_image; } } @@ -286,12 +301,11 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, efi_free(sys_table, initrd_size, initrd_addr); efi_free(sys_table, fdt_size, fdt_addr); -fail_free_cmdline: - efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr); - fail_free_image: efi_free(sys_table, image_size, *image_addr); efi_free(sys_table, reserve_size, reserve_addr); +fail_free_cmdline: + efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr); fail: return EFI_ERROR; } diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c index 78dfbd34b6bf..377d935a3380 100644 --- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -13,6 +13,10 @@ #include <asm/efi.h> #include <asm/sections.h> +#include "efistub.h" + +extern bool __nokaslr; + efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg, unsigned long *image_addr, unsigned long *image_size, @@ -23,26 +27,61 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg, { efi_status_t status; unsigned long kernel_size, kernel_memsize = 0; - unsigned long nr_pages; void *old_image_addr = (void *)*image_addr; unsigned long preferred_offset; + u64 phys_seed = 0; + + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { + if (!__nokaslr) { + status = efi_get_random_bytes(sys_table_arg, + sizeof(phys_seed), + (u8 *)&phys_seed); + if (status == EFI_NOT_FOUND) { + pr_efi(sys_table_arg, "EFI_RNG_PROTOCOL unavailable, no randomness supplied\n"); + } else if (status != EFI_SUCCESS) { + pr_efi_err(sys_table_arg, "efi_get_random_bytes() failed\n"); + return status; + } + } else { + pr_efi(sys_table_arg, "KASLR disabled on kernel command line\n"); + } + } /* * The preferred offset of the kernel Image is TEXT_OFFSET bytes beyond * a 2 MB aligned base, which itself may be lower than dram_base, as * long as the resulting offset equals or exceeds it. */ - preferred_offset = round_down(dram_base, SZ_2M) + TEXT_OFFSET; + preferred_offset = round_down(dram_base, MIN_KIMG_ALIGN) + TEXT_OFFSET; if (preferred_offset < dram_base) - preferred_offset += SZ_2M; + preferred_offset += MIN_KIMG_ALIGN; - /* Relocate the image, if required. */ kernel_size = _edata - _text; - if (*image_addr != preferred_offset) { - kernel_memsize = kernel_size + (_end - _edata); + kernel_memsize = kernel_size + (_end - _edata); + + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && phys_seed != 0) { + /* + * 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) + */ + u32 mask = (MIN_KIMG_ALIGN - 1) & ~(SZ_64K - 1); + u32 offset = !IS_ENABLED(CONFIG_DEBUG_ALIGN_RODATA) ? + (phys_seed >> 32) & mask : TEXT_OFFSET; + + /* + * If KASLR is enabled, and we have some randomness available, + * locate the kernel at a randomized offset in physical memory. + */ + *reserve_size = kernel_memsize + offset; + status = efi_random_alloc(sys_table_arg, *reserve_size, + MIN_KIMG_ALIGN, reserve_addr, + (u32)phys_seed); + *image_addr = *reserve_addr + offset; + } else { /* - * First, try a straight allocation at the preferred offset. + * Else, try a straight allocation at the preferred offset. * This will work around the issue where, if dram_base == 0x0, * efi_low_alloc() refuses to allocate at 0x0 (to prevent the * address of the allocation to be mistaken for a FAIL return @@ -52,27 +91,31 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg, * Mustang), we can still place the kernel at the address * 'dram_base + TEXT_OFFSET'. */ + if (*image_addr == preferred_offset) + return EFI_SUCCESS; + *image_addr = *reserve_addr = preferred_offset; - nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) / - EFI_PAGE_SIZE; + *reserve_size = round_up(kernel_memsize, EFI_ALLOC_ALIGN); + status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS, - EFI_LOADER_DATA, nr_pages, + EFI_LOADER_DATA, + *reserve_size / EFI_PAGE_SIZE, (efi_physical_addr_t *)reserve_addr); - if (status != EFI_SUCCESS) { - kernel_memsize += TEXT_OFFSET; - status = efi_low_alloc(sys_table_arg, kernel_memsize, - SZ_2M, reserve_addr); + } - if (status != EFI_SUCCESS) { - pr_efi_err(sys_table_arg, "Failed to relocate kernel\n"); - return status; - } - *image_addr = *reserve_addr + TEXT_OFFSET; + if (status != EFI_SUCCESS) { + *reserve_size = kernel_memsize + TEXT_OFFSET; + status = efi_low_alloc(sys_table_arg, *reserve_size, + MIN_KIMG_ALIGN, reserve_addr); + + if (status != EFI_SUCCESS) { + pr_efi_err(sys_table_arg, "Failed to relocate kernel\n"); + *reserve_size = 0; + return status; } - memcpy((void *)*image_addr, old_image_addr, kernel_size); - *reserve_size = kernel_memsize; + *image_addr = *reserve_addr + TEXT_OFFSET; } - + memcpy((void *)*image_addr, old_image_addr, kernel_size); return EFI_SUCCESS; } diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c index f07d4a67fa76..29ed2f9b218c 100644 --- a/drivers/firmware/efi/libstub/efi-stub-helper.c +++ b/drivers/firmware/efi/libstub/efi-stub-helper.c @@ -649,6 +649,10 @@ static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n) return dst; } +#ifndef MAX_CMDLINE_ADDRESS +#define MAX_CMDLINE_ADDRESS ULONG_MAX +#endif + /* * Convert the unicode UEFI command line to ASCII to pass to kernel. * Size of memory allocated return in *cmd_line_len. @@ -684,7 +688,8 @@ char *efi_convert_cmdline(efi_system_table_t *sys_table_arg, options_bytes++; /* NUL termination */ - status = efi_low_alloc(sys_table_arg, options_bytes, 0, &cmdline_addr); + status = efi_high_alloc(sys_table_arg, options_bytes, 0, + &cmdline_addr, MAX_CMDLINE_ADDRESS); if (status != EFI_SUCCESS) return NULL; diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h index 6b6548fda089..5ed3d3f38166 100644 --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -43,4 +43,11 @@ void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, unsigned long desc_size, efi_memory_desc_t *runtime_map, int *count); +efi_status_t efi_get_random_bytes(efi_system_table_t *sys_table, + unsigned long size, u8 *out); + +efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg, + unsigned long size, unsigned long align, + unsigned long *addr, unsigned long random_seed); + #endif diff --git a/drivers/firmware/efi/libstub/fdt.c b/drivers/firmware/efi/libstub/fdt.c index b62e2f5dcab3..b1c22cf18f7d 100644 --- a/drivers/firmware/efi/libstub/fdt.c +++ b/drivers/firmware/efi/libstub/fdt.c @@ -147,6 +147,20 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt, if (status) goto fdt_set_fail; + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { + efi_status_t efi_status; + + efi_status = efi_get_random_bytes(sys_table, sizeof(fdt_val64), + (u8 *)&fdt_val64); + if (efi_status == EFI_SUCCESS) { + status = fdt_setprop(fdt, node, "kaslr-seed", + &fdt_val64, sizeof(fdt_val64)); + if (status) + goto fdt_set_fail; + } else if (efi_status != EFI_NOT_FOUND) { + return efi_status; + } + } return EFI_SUCCESS; fdt_set_fail: diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c new file mode 100644 index 000000000000..53f6d3fe6d86 --- /dev/null +++ b/drivers/firmware/efi/libstub/random.c @@ -0,0 +1,135 @@ +/* + * Copyright (C) 2016 Linaro Ltd; <ard.biesheuvel@linaro.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ + +#include <linux/efi.h> +#include <asm/efi.h> + +#include "efistub.h" + +struct efi_rng_protocol { + efi_status_t (*get_info)(struct efi_rng_protocol *, + unsigned long *, efi_guid_t *); + efi_status_t (*get_rng)(struct efi_rng_protocol *, + efi_guid_t *, unsigned long, u8 *out); +}; + +efi_status_t efi_get_random_bytes(efi_system_table_t *sys_table_arg, + unsigned long size, u8 *out) +{ + efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID; + efi_status_t status; + struct efi_rng_protocol *rng; + + status = efi_call_early(locate_protocol, &rng_proto, NULL, + (void **)&rng); + if (status != EFI_SUCCESS) + return status; + + return rng->get_rng(rng, NULL, size, out); +} + +/* + * Return the number of slots covered by this entry, i.e., the number of + * addresses it covers that are suitably aligned and supply enough room + * for the allocation. + */ +static unsigned long get_entry_num_slots(efi_memory_desc_t *md, + unsigned long size, + unsigned long align) +{ + u64 start, end; + + if (md->type != EFI_CONVENTIONAL_MEMORY) + return 0; + + start = round_up(md->phys_addr, align); + end = round_down(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - size, + align); + + if (start > end) + return 0; + + return (end - start + 1) / align; +} + +/* + * The UEFI memory descriptors have a virtual address field that is only used + * when installing the virtual mapping using SetVirtualAddressMap(). Since it + * is unused here, we can reuse it to keep track of each descriptor's slot + * count. + */ +#define MD_NUM_SLOTS(md) ((md)->virt_addr) + +efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg, + unsigned long size, + unsigned long align, + unsigned long *addr, + unsigned long random_seed) +{ + unsigned long map_size, desc_size, total_slots = 0, target_slot; + efi_status_t status; + efi_memory_desc_t *memory_map; + int map_offset; + + status = efi_get_memory_map(sys_table_arg, &memory_map, &map_size, + &desc_size, NULL, NULL); + if (status != EFI_SUCCESS) + return status; + + if (align < EFI_ALLOC_ALIGN) + align = EFI_ALLOC_ALIGN; + + /* count the suitable slots in each memory map entry */ + for (map_offset = 0; map_offset < map_size; map_offset += desc_size) { + efi_memory_desc_t *md = (void *)memory_map + map_offset; + unsigned long slots; + + slots = get_entry_num_slots(md, size, align); + MD_NUM_SLOTS(md) = slots; + total_slots += slots; + } + + /* find a random number between 0 and total_slots */ + target_slot = (total_slots * (u16)random_seed) >> 16; + + /* + * target_slot is now a value in the range [0, total_slots), and so + * it corresponds with exactly one of the suitable slots we recorded + * when iterating over the memory map the first time around. + * + * So iterate over the memory map again, subtracting the number of + * slots of each entry at each iteration, until we have found the entry + * that covers our chosen slot. Use the residual value of target_slot + * to calculate the randomly chosen address, and allocate it directly + * using EFI_ALLOCATE_ADDRESS. + */ + for (map_offset = 0; map_offset < map_size; map_offset += desc_size) { + efi_memory_desc_t *md = (void *)memory_map + map_offset; + efi_physical_addr_t target; + unsigned long pages; + + if (target_slot >= MD_NUM_SLOTS(md)) { + target_slot -= MD_NUM_SLOTS(md); + continue; + } + + target = round_up(md->phys_addr, align) + target_slot * align; + pages = round_up(size, EFI_PAGE_SIZE) / EFI_PAGE_SIZE; + + status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS, + EFI_LOADER_DATA, pages, &target); + if (status == EFI_SUCCESS) + *addr = target; + break; + } + + efi_call_early(free_pool, memory_map); + + return status; +} |