| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright (C) 2020 Arm Limited |
| * |
| * Based on arch/arm64/kernel/machine_kexec_file.c: |
| * Copyright (C) 2018 Linaro Limited |
| * |
| * And arch/powerpc/kexec/file_load.c: |
| * Copyright (C) 2016 IBM Corporation |
| */ |
| |
| #include <linux/ima.h> |
| #include <linux/kernel.h> |
| #include <linux/kexec.h> |
| #include <linux/memblock.h> |
| #include <linux/libfdt.h> |
| #include <linux/of.h> |
| #include <linux/of_fdt.h> |
| #include <linux/random.h> |
| #include <linux/slab.h> |
| #include <linux/types.h> |
| |
| #define RNG_SEED_SIZE 128 |
| |
| /* |
| * Additional space needed for the FDT buffer so that we can add initrd, |
| * bootargs, kaslr-seed, rng-seed, useable-memory-range and elfcorehdr. |
| */ |
| #define FDT_EXTRA_SPACE 0x1000 |
| |
| /** |
| * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size |
| * |
| * @fdt: Flattened device tree for the current kernel. |
| * @start: Starting address of the reserved memory. |
| * @size: Size of the reserved memory. |
| * |
| * Return: 0 on success, or negative errno on error. |
| */ |
| static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size) |
| { |
| int i, ret, num_rsvs = fdt_num_mem_rsv(fdt); |
| |
| for (i = 0; i < num_rsvs; i++) { |
| u64 rsv_start, rsv_size; |
| |
| ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size); |
| if (ret) { |
| pr_err("Malformed device tree.\n"); |
| return -EINVAL; |
| } |
| |
| if (rsv_start == start && rsv_size == size) { |
| ret = fdt_del_mem_rsv(fdt, i); |
| if (ret) { |
| pr_err("Error deleting device tree reservation.\n"); |
| return -EINVAL; |
| } |
| |
| return 0; |
| } |
| } |
| |
| return -ENOENT; |
| } |
| |
| /** |
| * get_addr_size_cells - Get address and size of root node |
| * |
| * @addr_cells: Return address of the root node |
| * @size_cells: Return size of the root node |
| * |
| * Return: 0 on success, or negative errno on error. |
| */ |
| static int get_addr_size_cells(int *addr_cells, int *size_cells) |
| { |
| struct device_node *root; |
| |
| root = of_find_node_by_path("/"); |
| if (!root) |
| return -EINVAL; |
| |
| *addr_cells = of_n_addr_cells(root); |
| *size_cells = of_n_size_cells(root); |
| |
| of_node_put(root); |
| |
| return 0; |
| } |
| |
| /** |
| * do_get_kexec_buffer - Get address and size of device tree property |
| * |
| * @prop: Device tree property |
| * @len: Size of @prop |
| * @addr: Return address of the node |
| * @size: Return size of the node |
| * |
| * Return: 0 on success, or negative errno on error. |
| */ |
| static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr, |
| size_t *size) |
| { |
| int ret, addr_cells, size_cells; |
| |
| ret = get_addr_size_cells(&addr_cells, &size_cells); |
| if (ret) |
| return ret; |
| |
| if (len < 4 * (addr_cells + size_cells)) |
| return -ENOENT; |
| |
| *addr = of_read_number(prop, addr_cells); |
| *size = of_read_number(prop + 4 * addr_cells, size_cells); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_HAVE_IMA_KEXEC |
| /** |
| * ima_get_kexec_buffer - get IMA buffer from the previous kernel |
| * @addr: On successful return, set to point to the buffer contents. |
| * @size: On successful return, set to the buffer size. |
| * |
| * Return: 0 on success, negative errno on error. |
| */ |
| int __init ima_get_kexec_buffer(void **addr, size_t *size) |
| { |
| int ret, len; |
| unsigned long tmp_addr; |
| unsigned long start_pfn, end_pfn; |
| size_t tmp_size; |
| const void *prop; |
| |
| prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len); |
| if (!prop) |
| return -ENOENT; |
| |
| ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size); |
| if (ret) |
| return ret; |
| |
| /* Do some sanity on the returned size for the ima-kexec buffer */ |
| if (!tmp_size) |
| return -ENOENT; |
| |
| /* |
| * Calculate the PFNs for the buffer and ensure |
| * they are with in addressable memory. |
| */ |
| start_pfn = PHYS_PFN(tmp_addr); |
| end_pfn = PHYS_PFN(tmp_addr + tmp_size - 1); |
| if (!page_is_ram(start_pfn) || !page_is_ram(end_pfn)) { |
| pr_warn("IMA buffer at 0x%lx, size = 0x%zx beyond memory\n", |
| tmp_addr, tmp_size); |
| return -EINVAL; |
| } |
| |
| *addr = __va(tmp_addr); |
| *size = tmp_size; |
| |
| return 0; |
| } |
| |
| /** |
| * ima_free_kexec_buffer - free memory used by the IMA buffer |
| */ |
| int __init ima_free_kexec_buffer(void) |
| { |
| int ret; |
| unsigned long addr; |
| size_t size; |
| struct property *prop; |
| |
| prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL); |
| if (!prop) |
| return -ENOENT; |
| |
| ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size); |
| if (ret) |
| return ret; |
| |
| ret = of_remove_property(of_chosen, prop); |
| if (ret) |
| return ret; |
| |
| return memblock_phys_free(addr, size); |
| } |
| #endif |
| |
| /** |
| * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt |
| * |
| * @fdt: Flattened Device Tree to update |
| * @chosen_node: Offset to the chosen node in the device tree |
| * |
| * The IMA measurement buffer is of no use to a subsequent kernel, so we always |
| * remove it from the device tree. |
| */ |
| static void remove_ima_buffer(void *fdt, int chosen_node) |
| { |
| int ret, len; |
| unsigned long addr; |
| size_t size; |
| const void *prop; |
| |
| if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC)) |
| return; |
| |
| prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len); |
| if (!prop) |
| return; |
| |
| ret = do_get_kexec_buffer(prop, len, &addr, &size); |
| fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer"); |
| if (ret) |
| return; |
| |
| ret = fdt_find_and_del_mem_rsv(fdt, addr, size); |
| if (!ret) |
| pr_debug("Removed old IMA buffer reservation.\n"); |
| } |
| |
| #ifdef CONFIG_IMA_KEXEC |
| /** |
| * setup_ima_buffer - add IMA buffer information to the fdt |
| * @image: kexec image being loaded. |
| * @fdt: Flattened device tree for the next kernel. |
| * @chosen_node: Offset to the chosen node. |
| * |
| * Return: 0 on success, or negative errno on error. |
| */ |
| static int setup_ima_buffer(const struct kimage *image, void *fdt, |
| int chosen_node) |
| { |
| int ret; |
| |
| if (!image->ima_buffer_size) |
| return 0; |
| |
| ret = fdt_appendprop_addrrange(fdt, 0, chosen_node, |
| "linux,ima-kexec-buffer", |
| image->ima_buffer_addr, |
| image->ima_buffer_size); |
| if (ret < 0) |
| return -EINVAL; |
| |
| ret = fdt_add_mem_rsv(fdt, image->ima_buffer_addr, |
| image->ima_buffer_size); |
| if (ret) |
| return -EINVAL; |
| |
| pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n", |
| image->ima_buffer_addr, image->ima_buffer_size); |
| |
| return 0; |
| } |
| #else /* CONFIG_IMA_KEXEC */ |
| static inline int setup_ima_buffer(const struct kimage *image, void *fdt, |
| int chosen_node) |
| { |
| return 0; |
| } |
| #endif /* CONFIG_IMA_KEXEC */ |
| |
| /* |
| * of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree |
| * |
| * @image: kexec image being loaded. |
| * @initrd_load_addr: Address where the next initrd will be loaded. |
| * @initrd_len: Size of the next initrd, or 0 if there will be none. |
| * @cmdline: Command line for the next kernel, or NULL if there will |
| * be none. |
| * @extra_fdt_size: Additional size for the new FDT buffer. |
| * |
| * Return: fdt on success, or NULL errno on error. |
| */ |
| void *of_kexec_alloc_and_setup_fdt(const struct kimage *image, |
| unsigned long initrd_load_addr, |
| unsigned long initrd_len, |
| const char *cmdline, size_t extra_fdt_size) |
| { |
| void *fdt; |
| int ret, chosen_node; |
| const void *prop; |
| size_t fdt_size; |
| |
| fdt_size = fdt_totalsize(initial_boot_params) + |
| (cmdline ? strlen(cmdline) : 0) + |
| FDT_EXTRA_SPACE + |
| extra_fdt_size; |
| fdt = kvmalloc(fdt_size, GFP_KERNEL); |
| if (!fdt) |
| return NULL; |
| |
| ret = fdt_open_into(initial_boot_params, fdt, fdt_size); |
| if (ret < 0) { |
| pr_err("Error %d setting up the new device tree.\n", ret); |
| goto out; |
| } |
| |
| /* Remove memory reservation for the current device tree. */ |
| ret = fdt_find_and_del_mem_rsv(fdt, __pa(initial_boot_params), |
| fdt_totalsize(initial_boot_params)); |
| if (ret == -EINVAL) { |
| pr_err("Error removing memory reservation.\n"); |
| goto out; |
| } |
| |
| chosen_node = fdt_path_offset(fdt, "/chosen"); |
| if (chosen_node == -FDT_ERR_NOTFOUND) |
| chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"), |
| "chosen"); |
| if (chosen_node < 0) { |
| ret = chosen_node; |
| goto out; |
| } |
| |
| ret = fdt_delprop(fdt, chosen_node, "linux,elfcorehdr"); |
| if (ret && ret != -FDT_ERR_NOTFOUND) |
| goto out; |
| ret = fdt_delprop(fdt, chosen_node, "linux,usable-memory-range"); |
| if (ret && ret != -FDT_ERR_NOTFOUND) |
| goto out; |
| |
| /* Did we boot using an initrd? */ |
| prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", NULL); |
| if (prop) { |
| u64 tmp_start, tmp_end, tmp_size; |
| |
| tmp_start = fdt64_to_cpu(*((const fdt64_t *) prop)); |
| |
| prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", NULL); |
| if (!prop) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| tmp_end = fdt64_to_cpu(*((const fdt64_t *) prop)); |
| |
| /* |
| * kexec reserves exact initrd size, while firmware may |
| * reserve a multiple of PAGE_SIZE, so check for both. |
| */ |
| tmp_size = tmp_end - tmp_start; |
| ret = fdt_find_and_del_mem_rsv(fdt, tmp_start, tmp_size); |
| if (ret == -ENOENT) |
| ret = fdt_find_and_del_mem_rsv(fdt, tmp_start, |
| round_up(tmp_size, PAGE_SIZE)); |
| if (ret == -EINVAL) |
| goto out; |
| } |
| |
| /* add initrd-* */ |
| if (initrd_load_addr) { |
| ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-start", |
| initrd_load_addr); |
| if (ret) |
| goto out; |
| |
| ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end", |
| initrd_load_addr + initrd_len); |
| if (ret) |
| goto out; |
| |
| ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len); |
| if (ret) |
| goto out; |
| |
| } else { |
| ret = fdt_delprop(fdt, chosen_node, "linux,initrd-start"); |
| if (ret && (ret != -FDT_ERR_NOTFOUND)) |
| goto out; |
| |
| ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end"); |
| if (ret && (ret != -FDT_ERR_NOTFOUND)) |
| goto out; |
| } |
| |
| if (image->type == KEXEC_TYPE_CRASH) { |
| /* add linux,elfcorehdr */ |
| ret = fdt_appendprop_addrrange(fdt, 0, chosen_node, |
| "linux,elfcorehdr", image->elf_load_addr, |
| image->elf_headers_sz); |
| if (ret) |
| goto out; |
| |
| /* |
| * Avoid elfcorehdr from being stomped on in kdump kernel by |
| * setting up memory reserve map. |
| */ |
| ret = fdt_add_mem_rsv(fdt, image->elf_load_addr, |
| image->elf_headers_sz); |
| if (ret) |
| goto out; |
| |
| /* add linux,usable-memory-range */ |
| ret = fdt_appendprop_addrrange(fdt, 0, chosen_node, |
| "linux,usable-memory-range", crashk_res.start, |
| crashk_res.end - crashk_res.start + 1); |
| if (ret) |
| goto out; |
| |
| if (crashk_low_res.end) { |
| ret = fdt_appendprop_addrrange(fdt, 0, chosen_node, |
| "linux,usable-memory-range", |
| crashk_low_res.start, |
| crashk_low_res.end - crashk_low_res.start + 1); |
| if (ret) |
| goto out; |
| } |
| } |
| |
| /* add bootargs */ |
| if (cmdline) { |
| ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline); |
| if (ret) |
| goto out; |
| } else { |
| ret = fdt_delprop(fdt, chosen_node, "bootargs"); |
| if (ret && (ret != -FDT_ERR_NOTFOUND)) |
| goto out; |
| } |
| |
| /* add kaslr-seed */ |
| ret = fdt_delprop(fdt, chosen_node, "kaslr-seed"); |
| if (ret == -FDT_ERR_NOTFOUND) |
| ret = 0; |
| else if (ret) |
| goto out; |
| |
| if (rng_is_initialized()) { |
| u64 seed = get_random_u64(); |
| |
| ret = fdt_setprop_u64(fdt, chosen_node, "kaslr-seed", seed); |
| if (ret) |
| goto out; |
| } else { |
| pr_notice("RNG is not initialised: omitting \"%s\" property\n", |
| "kaslr-seed"); |
| } |
| |
| /* add rng-seed */ |
| if (rng_is_initialized()) { |
| void *rng_seed; |
| |
| ret = fdt_setprop_placeholder(fdt, chosen_node, "rng-seed", |
| RNG_SEED_SIZE, &rng_seed); |
| if (ret) |
| goto out; |
| get_random_bytes(rng_seed, RNG_SEED_SIZE); |
| } else { |
| pr_notice("RNG is not initialised: omitting \"%s\" property\n", |
| "rng-seed"); |
| } |
| |
| ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0); |
| if (ret) |
| goto out; |
| |
| remove_ima_buffer(fdt, chosen_node); |
| ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen")); |
| |
| out: |
| if (ret) { |
| kvfree(fdt); |
| fdt = NULL; |
| } |
| |
| return fdt; |
| } |