// SPDX-License-Identifier: GPL-2.0-only /* * kexec: kexec_file_load system call * * Copyright (C) 2014 Red Hat Inc. * Authors: * Vivek Goyal */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "kexec_internal.h" #ifdef CONFIG_KEXEC_SIG static bool sig_enforce = IS_ENABLED(CONFIG_KEXEC_SIG_FORCE); void set_kexec_sig_enforced(void) { sig_enforce = true; } #endif static int kexec_calculate_store_digests(struct kimage *image); /* Maximum size in bytes for kernel/initrd files. */ #define KEXEC_FILE_SIZE_MAX min_t(s64, 4LL << 30, SSIZE_MAX) /* * Currently this is the only default function that is exported as some * architectures need it to do additional handlings. * In the future, other default functions may be exported too if required. */ int kexec_image_probe_default(struct kimage *image, void *buf, unsigned long buf_len) { const struct kexec_file_ops * const *fops; int ret = -ENOEXEC; for (fops = &kexec_file_loaders[0]; *fops && (*fops)->probe; ++fops) { ret = (*fops)->probe(buf, buf_len); if (!ret) { image->fops = *fops; return ret; } } return ret; } static void *kexec_image_load_default(struct kimage *image) { if (!image->fops || !image->fops->load) return ERR_PTR(-ENOEXEC); return image->fops->load(image, image->kernel_buf, image->kernel_buf_len, image->initrd_buf, image->initrd_buf_len, image->cmdline_buf, image->cmdline_buf_len); } int kexec_image_post_load_cleanup_default(struct kimage *image) { if (!image->fops || !image->fops->cleanup) return 0; return image->fops->cleanup(image->image_loader_data); } /* * Free up memory used by kernel, initrd, and command line. This is temporary * memory allocation which is not needed any more after these buffers have * been loaded into separate segments and have been copied elsewhere. */ void kimage_file_post_load_cleanup(struct kimage *image) { struct purgatory_info *pi = &image->purgatory_info; vfree(image->kernel_buf); image->kernel_buf = NULL; vfree(image->initrd_buf); image->initrd_buf = NULL; kfree(image->cmdline_buf); image->cmdline_buf = NULL; vfree(pi->purgatory_buf); pi->purgatory_buf = NULL; vfree(pi->sechdrs); pi->sechdrs = NULL; #ifdef CONFIG_IMA_KEXEC vfree(image->ima_buffer); image->ima_buffer = NULL; #endif /* CONFIG_IMA_KEXEC */ /* See if architecture has anything to cleanup post load */ arch_kimage_file_post_load_cleanup(image); /* * Above call should have called into bootloader to free up * any data stored in kimage->image_loader_data. It should * be ok now to free it up. */ kfree(image->image_loader_data); image->image_loader_data = NULL; } #ifdef CONFIG_KEXEC_SIG #ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION int kexec_kernel_verify_pe_sig(const char *kernel, unsigned long kernel_len) { int ret; ret = verify_pefile_signature(kernel, kernel_len, VERIFY_USE_SECONDARY_KEYRING, VERIFYING_KEXEC_PE_SIGNATURE); if (ret == -ENOKEY && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) { ret = verify_pefile_signature(kernel, kernel_len, VERIFY_USE_PLATFORM_KEYRING, VERIFYING_KEXEC_PE_SIGNATURE); } return ret; } #endif static int kexec_image_verify_sig(struct kimage *image, void *buf, unsigned long buf_len) { if (!image->fops || !image->fops->verify_sig) { pr_debug("kernel loader does not support signature verification.\n"); return -EKEYREJECTED; } return image->fops->verify_sig(buf, buf_len); } static int kimage_validate_signature(struct kimage *image) { int ret; ret = kexec_image_verify_sig(image, image->kernel_buf, image->kernel_buf_len); if (ret) { if (sig_enforce) { pr_notice("Enforced kernel signature verification failed (%d).\n", ret); return ret; } /* * If IMA is guaranteed to appraise a signature on the kexec * image, permit it even if the kernel is otherwise locked * down. */ if (!ima_appraise_signature(READING_KEXEC_IMAGE) && security_locked_down(LOCKDOWN_KEXEC)) return -EPERM; pr_debug("kernel signature verification failed (%d).\n", ret); } return 0; } #endif /* * In file mode list of segments is prepared by kernel. Copy relevant * data from user space, do error checking, prepare segment list */ static int kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd, const char __user *cmdline_ptr, unsigned long cmdline_len, unsigned flags) { ssize_t ret; void *ldata; ret = kernel_read_file_from_fd(kernel_fd, 0, &image->kernel_buf, KEXEC_FILE_SIZE_MAX, NULL, READING_KEXEC_IMAGE); if (ret < 0) return ret; image->kernel_buf_len = ret; /* Call arch image probe handlers */ ret = arch_kexec_kernel_image_probe(image, image->kernel_buf, image->kernel_buf_len); if (ret) goto out; #ifdef CONFIG_KEXEC_SIG ret = kimage_validate_signature(image); if (ret) goto out; #endif /* It is possible that there no initramfs is being loaded */ if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { ret = kernel_read_file_from_fd(initrd_fd, 0, &image->initrd_buf, KEXEC_FILE_SIZE_MAX, NULL, READING_KEXEC_INITRAMFS); if (ret < 0) goto out; image->initrd_buf_len = ret; ret = 0; } if (cmdline_len) { image->cmdline_buf = memdup_user(cmdline_ptr, cmdline_len); if (IS_ERR(image->cmdline_buf)) { ret = PTR_ERR(image->cmdline_buf); image->cmdline_buf = NULL; goto out; } image->cmdline_buf_len = cmdline_len; /* command line should be a string with last byte null */ if (image->cmdline_buf[cmdline_len - 1] != '\0') { ret = -EINVAL; goto out; } ima_kexec_cmdline(kernel_fd, image->cmdline_buf, image->cmdline_buf_len - 1); } /* IMA needs to pass the measurement list to the next kernel. */ ima_add_kexec_buffer(image); /* Call image load handler */ ldata = kexec_image_load_default(image); if (IS_ERR(ldata)) { ret = PTR_ERR(ldata); goto out; } image->image_loader_data = ldata; out: /* In case of error, free up all allocated memory in this function */ if (ret) kimage_file_post_load_cleanup(image); return ret; } static int kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, int initrd_fd, const char __user *cmdline_ptr, unsigned long cmdline_len, unsigned long flags) { int ret; struct kimage *image; bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH; image = do_kimage_alloc_init(); if (!image) return -ENOMEM; image->file_mode = 1; if (kexec_on_panic) { /* Enable special crash kernel control page alloc policy. */ image->control_page = crashk_res.start; image->type = KEXEC_TYPE_CRASH; } ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd, cmdline_ptr, cmdline_len, flags); if (ret) goto out_free_image; ret = sanity_check_segment_list(image); if (ret) goto out_free_post_load_bufs; ret = -ENOMEM; image->control_code_page = kimage_alloc_control_pages(image, get_order(KEXEC_CONTROL_PAGE_SIZE)); if (!image->control_code_page) { pr_err("Could not allocate control_code_buffer\n"); goto out_free_post_load_bufs; } if (!kexec_on_panic) { image->swap_page = kimage_alloc_control_pages(image, 0); if (!image->swap_page) { pr_err("Could not allocate swap buffer\n"); goto out_free_control_pages; } } *rimage = image; return 0; out_free_control_pages: kimage_free_page_list(&image->control_pages); out_free_post_load_bufs: kimage_file_post_load_cleanup(image); out_free_image: kfree(image); return ret; } SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, unsigned long, cmdline_len, const char __user *, cmdline_ptr, unsigned long, flags) { int image_type = (flags & KEXEC_FILE_ON_CRASH) ? KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT; struct kimage **dest_image, *image; int ret = 0, i; /* We only trust the superuser with rebooting the system. */ if (!kexec_load_permitted(image_type)) return -EPERM; /* Make sure we have a legal set of flags */ if (flags != (flags & KEXEC_FILE_FLAGS)) return -EINVAL; image = NULL; if (!kexec_trylock()) return -EBUSY; if (image_type == KEXEC_TYPE_CRASH) { dest_image = &kexec_crash_image; if (kexec_crash_image) arch_kexec_unprotect_crashkres(); } else { dest_image = &kexec_image; } if (flags & KEXEC_FILE_UNLOAD) goto exchange; /* * In case of crash, new kernel gets loaded in reserved region. It is * same memory where old crash kernel might be loaded. Free any * current crash dump kernel before we corrupt it. */ if (flags & KEXEC_FILE_ON_CRASH) kimage_free(xchg(&kexec_crash_image, NULL)); ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr, cmdline_len, flags); if (ret) goto out; ret = machine_kexec_prepare(image); if (ret) goto out; /* * Some architecture(like S390) may touch the crash memory before * machine_kexec_prepare(), we must copy vmcoreinfo data after it. */ ret = kimage_crash_copy_vmcoreinfo(image); if (ret) goto out; ret = kexec_calculate_store_digests(image); if (ret) goto out; for (i = 0; i < image->nr_segments; i++) { struct kexec_segment *ksegment; ksegment = &image->segment[i]; pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n", i, ksegment->buf, ksegment->bufsz, ksegment->mem, ksegment->memsz); ret = kimage_load_segment(image, &image->segment[i]); if (ret) goto out; } kimage_terminate(image); ret = machine_kexec_post_load(image); if (ret) goto out; /* * Free up any temporary buffers allocated which are not needed * after image has been loaded */ kimage_file_post_load_cleanup(image); exchange: image = xchg(dest_image, image); out: if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) arch_kexec_protect_crashkres(); kexec_unlock(); kimage_free(image); return ret; } static int locate_mem_hole_top_down(unsigned long start, unsigned long end, struct kexec_buf *kbuf) { struct kimage *image = kbuf->image; unsigned long temp_start, temp_end; temp_end = min(end, kbuf->buf_max); temp_start = temp_end - kbuf->memsz; do { /* align down start */ temp_start = temp_start & (~(kbuf->buf_align - 1)); if (temp_start < start || temp_start < kbuf->buf_min) return 0; temp_end = temp_start + kbuf->memsz - 1; /* * Make sure this does not conflict with any of existing * segments */ if (kimage_is_destination_range(image, temp_start, temp_end)) { temp_start = temp_start - PAGE_SIZE; continue; } /* We found a suitable memory range */ break; } while (1); /* If we are here, we found a suitable memory range */ kbuf->mem = temp_start; /* Success, stop navigating through remaining System RAM ranges */ return 1; } static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end, struct kexec_buf *kbuf) { struct kimage *image = kbuf->image; unsigned long temp_start, temp_end; temp_start = max(start, kbuf->buf_min); do { temp_start = ALIGN(temp_start, kbuf->buf_align); temp_end = temp_start + kbuf->memsz - 1; if (temp_end > end || temp_end > kbuf->buf_max) return 0; /* * Make sure this does not conflict with any of existing * segments */ if (kimage_is_destination_range(image, temp_start, temp_end)) { temp_start = temp_start + PAGE_SIZE; continue; } /* We found a suitable memory range */ break; } while (1); /* If we are here, we found a suitable memory range */ kbuf->mem = temp_start; /* Success, stop navigating through remaining System RAM ranges */ return 1; } static int locate_mem_hole_callback(struct resource *res, void *arg) { struct kexec_buf *kbuf = (struct kexec_buf *)arg; u64 start = res->start, end = res->end; unsigned long sz = end - start + 1; /* Returning 0 will take to next memory range */ /* Don't use memory that will be detected and handled by a driver. */ if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED) return 0; if (sz < kbuf->memsz) return 0; if (end < kbuf->buf_min || start > kbuf->buf_max) return 0; /* * Allocate memory top down with-in ram range. Otherwise bottom up * allocation. */ if (kbuf->top_down) return locate_mem_hole_top_down(start, end, kbuf); return locate_mem_hole_bottom_up(start, end, kbuf); } #ifdef CONFIG_ARCH_KEEP_MEMBLOCK static int kexec_walk_memblock(struct kexec_buf *kbuf, int (*func)(struct resource *, void *)) { int ret = 0; u64 i; phys_addr_t mstart, mend; struct resource res = { }; if (kbuf->image->type == KEXEC_TYPE_CRASH) return func(&crashk_res, kbuf); /* * Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See * IORESOURCE_SYSRAM_DRIVER_MANAGED handling in * locate_mem_hole_callback(). */ if (kbuf->top_down) { for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE, &mstart, &mend, NULL) { /* * In memblock, end points to the first byte after the * range while in kexec, end points to the last byte * in the range. */ res.start = mstart; res.end = mend - 1; ret = func(&res, kbuf); if (ret) break; } } else { for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, &mstart, &mend, NULL) { /* * In memblock, end points to the first byte after the * range while in kexec, end points to the last byte * in the range. */ res.start = mstart; res.end = mend - 1; ret = func(&res, kbuf); if (ret) break; } } return ret; } #else static int kexec_walk_memblock(struct kexec_buf *kbuf, int (*func)(struct resource *, void *)) { return 0; } #endif /** * kexec_walk_resources - call func(data) on free memory regions * @kbuf: Context info for the search. Also passed to @func. * @func: Function to call for each memory region. * * Return: The memory walk will stop when func returns a non-zero value * and that value will be returned. If all free regions are visited without * func returning non-zero, then zero will be returned. */ static int kexec_walk_resources(struct kexec_buf *kbuf, int (*func)(struct resource *, void *)) { if (kbuf->image->type == KEXEC_TYPE_CRASH) return walk_iomem_res_desc(crashk_res.desc, IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, crashk_res.start, crashk_res.end, kbuf, func); else return walk_system_ram_res(0, ULONG_MAX, kbuf, func); } /** * kexec_locate_mem_hole - find free memory for the purgatory or the next kernel * @kbuf: Parameters for the memory search. * * On success, kbuf->mem will have the start address of the memory region found. * * Return: 0 on success, negative errno on error. */ int kexec_locate_mem_hole(struct kexec_buf *kbuf) { int ret; /* Arch knows where to place */ if (kbuf->mem != KEXEC_BUF_MEM_UNKNOWN) return 0; if (!IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) ret = kexec_walk_resources(kbuf, locate_mem_hole_callback); else ret = kexec_walk_memblock(kbuf, locate_mem_hole_callback); return ret == 1 ? 0 : -EADDRNOTAVAIL; } /** * kexec_add_buffer - place a buffer in a kexec segment * @kbuf: Buffer contents and memory parameters. * * This function assumes that kexec_lock is held. * On successful return, @kbuf->mem will have the physical address of * the buffer in memory. * * Return: 0 on success, negative errno on error. */ int kexec_add_buffer(struct kexec_buf *kbuf) { struct kexec_segment *ksegment; int ret; /* Currently adding segment this way is allowed only in file mode */ if (!kbuf->image->file_mode) return -EINVAL; if (kbuf->image->nr_segments >= KEXEC_SEGMENT_MAX) return -EINVAL; /* * Make sure we are not trying to add buffer after allocating * control pages. All segments need to be placed first before * any control pages are allocated. As control page allocation * logic goes through list of segments to make sure there are * no destination overlaps. */ if (!list_empty(&kbuf->image->control_pages)) { WARN_ON(1); return -EINVAL; } /* Ensure minimum alignment needed for segments. */ kbuf->memsz = ALIGN(kbuf->memsz, PAGE_SIZE); kbuf->buf_align = max(kbuf->buf_align, PAGE_SIZE); /* Walk the RAM ranges and allocate a suitable range for the buffer */ ret = arch_kexec_locate_mem_hole(kbuf); if (ret) return ret; /* Found a suitable memory range */ ksegment = &kbuf->image->segment[kbuf->image->nr_segments]; ksegment->kbuf = kbuf->buffer; ksegment->bufsz = kbuf->bufsz; ksegment->mem = kbuf->mem; ksegment->memsz = kbuf->memsz; kbuf->image->nr_segments++; return 0; } /* Calculate and store the digest of segments */ static int kexec_calculate_store_digests(struct kimage *image) { struct crypto_shash *tfm; struct shash_desc *desc; int ret = 0, i, j, zero_buf_sz, sha_region_sz; size_t desc_size, nullsz; char *digest; void *zero_buf; struct kexec_sha_region *sha_regions; struct purgatory_info *pi = &image->purgatory_info; if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY)) return 0; zero_buf = __va(page_to_pfn(ZERO_PAGE(0)) << PAGE_SHIFT); zero_buf_sz = PAGE_SIZE; tfm = crypto_alloc_shash("sha256", 0, 0); if (IS_ERR(tfm)) { ret = PTR_ERR(tfm); goto out; } desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); desc = kzalloc(desc_size, GFP_KERNEL); if (!desc) { ret = -ENOMEM; goto out_free_tfm; } sha_region_sz = KEXEC_SEGMENT_MAX * sizeof(struct kexec_sha_region); sha_regions = vzalloc(sha_region_sz); if (!sha_regions) { ret = -ENOMEM; goto out_free_desc; } desc->tfm = tfm; ret = crypto_shash_init(desc); if (ret < 0) goto out_free_sha_regions; digest = kzalloc(SHA256_DIGEST_SIZE, GFP_KERNEL); if (!digest) { ret = -ENOMEM; goto out_free_sha_regions; } for (j = i = 0; i < image->nr_segments; i++) { struct kexec_segment *ksegment; #ifdef CONFIG_CRASH_HOTPLUG /* Exclude elfcorehdr segment to allow future changes via hotplug */ if (i == image->elfcorehdr_index) continue; #endif ksegment = &image->segment[i]; /* * Skip purgatory as it will be modified once we put digest * info in purgatory. */ if (ksegment->kbuf == pi->purgatory_buf) continue; ret = crypto_shash_update(desc, ksegment->kbuf, ksegment->bufsz); if (ret) break; /* * Assume rest of the buffer is filled with zero and * update digest accordingly. */ nullsz = ksegment->memsz - ksegment->bufsz; while (nullsz) { unsigned long bytes = nullsz; if (bytes > zero_buf_sz) bytes = zero_buf_sz; ret = crypto_shash_update(desc, zero_buf, bytes); if (ret) break; nullsz -= bytes; } if (ret) break; sha_regions[j].start = ksegment->mem; sha_regions[j].len = ksegment->memsz; j++; } if (!ret) { ret = crypto_shash_final(desc, digest); if (ret) goto out_free_digest; ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha_regions", sha_regions, sha_region_sz, 0); if (ret) goto out_free_digest; ret = kexec_purgatory_get_set_symbol(image, "purgatory_sha256_digest", digest, SHA256_DIGEST_SIZE, 0); if (ret) goto out_free_digest; } out_free_digest: kfree(digest); out_free_sha_regions: vfree(sha_regions); out_free_desc: kfree(desc); out_free_tfm: kfree(tfm); out: return ret; } #ifdef CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY /* * kexec_purgatory_setup_kbuf - prepare buffer to load purgatory. * @pi: Purgatory to be loaded. * @kbuf: Buffer to setup. * * Allocates the memory needed for the buffer. Caller is responsible to free * the memory after use. * * Return: 0 on success, negative errno on error. */ static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi, struct kexec_buf *kbuf) { const Elf_Shdr *sechdrs; unsigned long bss_align; unsigned long bss_sz; unsigned long align; int i, ret; sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; kbuf->buf_align = bss_align = 1; kbuf->bufsz = bss_sz = 0; for (i = 0; i < pi->ehdr->e_shnum; i++) { if (!(sechdrs[i].sh_flags & SHF_ALLOC)) continue; align = sechdrs[i].sh_addralign; if (sechdrs[i].sh_type != SHT_NOBITS) { if (kbuf->buf_align < align) kbuf->buf_align = align; kbuf->bufsz = ALIGN(kbuf->bufsz, align); kbuf->bufsz += sechdrs[i].sh_size; } else { if (bss_align < align) bss_align = align; bss_sz = ALIGN(bss_sz, align); bss_sz += sechdrs[i].sh_size; } } kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align); kbuf->memsz = kbuf->bufsz + bss_sz; if (kbuf->buf_align < bss_align) kbuf->buf_align = bss_align; kbuf->buffer = vzalloc(kbuf->bufsz); if (!kbuf->buffer) return -ENOMEM; pi->purgatory_buf = kbuf->buffer; ret = kexec_add_buffer(kbuf); if (ret) goto out; return 0; out: vfree(pi->purgatory_buf); pi->purgatory_buf = NULL; return ret; } /* * kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer. * @pi: Purgatory to be loaded. * @kbuf: Buffer prepared to store purgatory. * * Allocates the memory needed for the buffer. Caller is responsible to free * the memory after use. * * Return: 0 on success, negative errno on error. */ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi, struct kexec_buf *kbuf) { unsigned long bss_addr; unsigned long offset; size_t sechdrs_size; Elf_Shdr *sechdrs; int i; /* * The section headers in kexec_purgatory are read-only. In order to * have them modifiable make a temporary copy. */ sechdrs_size = array_size(sizeof(Elf_Shdr), pi->ehdr->e_shnum); sechdrs = vzalloc(sechdrs_size); if (!sechdrs) return -ENOMEM; memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff, sechdrs_size); pi->sechdrs = sechdrs; offset = 0; bss_addr = kbuf->mem + kbuf->bufsz; kbuf->image->start = pi->ehdr->e_entry; for (i = 0; i < pi->ehdr->e_shnum; i++) { unsigned long align; void *src, *dst; if (!(sechdrs[i].sh_flags & SHF_ALLOC)) continue; align = sechdrs[i].sh_addralign; if (sechdrs[i].sh_type == SHT_NOBITS) { bss_addr = ALIGN(bss_addr, align); sechdrs[i].sh_addr = bss_addr; bss_addr += sechdrs[i].sh_size; continue; } offset = ALIGN(offset, align); /* * Check if the segment contains the entry point, if so, * calculate the value of image->start based on it. * If the compiler has produced more than one .text section * (Eg: .text.hot), they are generally after the main .text * section, and they shall not be used to calculate * image->start. So do not re-calculate image->start if it * is not set to the initial value, and warn the user so they * have a chance to fix their purgatory's linker script. */ if (sechdrs[i].sh_flags & SHF_EXECINSTR && pi->ehdr->e_entry >= sechdrs[i].sh_addr && pi->ehdr->e_entry < (sechdrs[i].sh_addr + sechdrs[i].sh_size) && !WARN_ON(kbuf->image->start != pi->ehdr->e_entry)) { kbuf->image->start -= sechdrs[i].sh_addr; kbuf->image->start += kbuf->mem + offset; } src = (void *)pi->ehdr + sechdrs[i].sh_offset; dst = pi->purgatory_buf + offset; memcpy(dst, src, sechdrs[i].sh_size); sechdrs[i].sh_addr = kbuf->mem + offset; sechdrs[i].sh_offset = offset; offset += sechdrs[i].sh_size; } return 0; } static int kexec_apply_relocations(struct kimage *image) { int i, ret; struct purgatory_info *pi = &image->purgatory_info; const Elf_Shdr *sechdrs; sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff; for (i = 0; i < pi->ehdr->e_shnum; i++) { const Elf_Shdr *relsec; const Elf_Shdr *symtab; Elf_Shdr *section; relsec = sechdrs + i; if (relsec->sh_type != SHT_RELA && relsec->sh_type != SHT_REL) continue; /* * For section of type SHT_RELA/SHT_REL, * ->sh_link contains section header index of associated * symbol table. And ->sh_info contains section header * index of section to which relocations apply. */ if (relsec->sh_info >= pi->ehdr->e_shnum || relsec->sh_link >= pi->ehdr->e_shnum) return -ENOEXEC; section = pi->sechdrs + relsec->sh_info; symtab = sechdrs + relsec->sh_link; if (!(section->sh_flags & SHF_ALLOC)) continue; /* * symtab->sh_link contain section header index of associated * string table. */ if (symtab->sh_link >= pi->ehdr->e_shnum) /* Invalid section number? */ continue; /* * Respective architecture needs to provide support for applying * relocations of type SHT_RELA/SHT_REL. */ if (relsec->sh_type == SHT_RELA) ret = arch_kexec_apply_relocations_add(pi, section, relsec, symtab); else if (relsec->sh_type == SHT_REL) ret = arch_kexec_apply_relocations(pi, section, relsec, symtab); if (ret) return ret; } return 0; } /* * kexec_load_purgatory - Load and relocate the purgatory object. * @image: Image to add the purgatory to. * @kbuf: Memory parameters to use. * * Allocates the memory needed for image->purgatory_info.sechdrs and * image->purgatory_info.purgatory_buf/kbuf->buffer. Caller is responsible * to free the memory after use. * * Return: 0 on success, negative errno on error. */ int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf) { struct purgatory_info *pi = &image->purgatory_info; int ret; if (kexec_purgatory_size <= 0) return -EINVAL; pi->ehdr = (const Elf_Ehdr *)kexec_purgatory; ret = kexec_purgatory_setup_kbuf(pi, kbuf); if (ret) return ret; ret = kexec_purgatory_setup_sechdrs(pi, kbuf); if (ret) goto out_free_kbuf; ret = kexec_apply_relocations(image); if (ret) goto out; return 0; out: vfree(pi->sechdrs); pi->sechdrs = NULL; out_free_kbuf: vfree(pi->purgatory_buf); pi->purgatory_buf = NULL; return ret; } /* * kexec_purgatory_find_symbol - find a symbol in the purgatory * @pi: Purgatory to search in. * @name: Name of the symbol. * * Return: pointer to symbol in read-only symtab on success, NULL on error. */ static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, const char *name) { const Elf_Shdr *sechdrs; const Elf_Ehdr *ehdr; const Elf_Sym *syms; const char *strtab; int i, k; if (!pi->ehdr) return NULL; ehdr = pi->ehdr; sechdrs = (void *)ehdr + ehdr->e_shoff; for (i = 0; i < ehdr->e_shnum; i++) { if (sechdrs[i].sh_type != SHT_SYMTAB) continue; if (sechdrs[i].sh_link >= ehdr->e_shnum) /* Invalid strtab section number */ continue; strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset; syms = (void *)ehdr + sechdrs[i].sh_offset; /* Go through symbols for a match */ for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) { if (ELF_ST_BIND(syms[k].st_info) != STB_GLOBAL) continue; if (strcmp(strtab + syms[k].st_name, name) != 0) continue; if (syms[k].st_shndx == SHN_UNDEF || syms[k].st_shndx >= ehdr->e_shnum) { pr_debug("Symbol: %s has bad section index %d.\n", name, syms[k].st_shndx); return NULL; } /* Found the symbol we are looking for */ return &syms[k]; } } return NULL; } void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) { struct purgatory_info *pi = &image->purgatory_info; const Elf_Sym *sym; Elf_Shdr *sechdr; sym = kexec_purgatory_find_symbol(pi, name); if (!sym) return ERR_PTR(-EINVAL); sechdr = &pi->sechdrs[sym->st_shndx]; /* * Returns the address where symbol will finally be loaded after * kexec_load_segment() */ return (void *)(sechdr->sh_addr + sym->st_value); } /* * Get or set value of a symbol. If "get_value" is true, symbol value is * returned in buf otherwise symbol value is set based on value in buf. */ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, void *buf, unsigned int size, bool get_value) { struct purgatory_info *pi = &image->purgatory_info; const Elf_Sym *sym; Elf_Shdr *sec; char *sym_buf; sym = kexec_purgatory_find_symbol(pi, name); if (!sym) return -EINVAL; if (sym->st_size != size) { pr_err("symbol %s size mismatch: expected %lu actual %u\n", name, (unsigned long)sym->st_size, size); return -EINVAL; } sec = pi->sechdrs + sym->st_shndx; if (sec->sh_type == SHT_NOBITS) { pr_err("symbol %s is in a bss section. Cannot %s\n", name, get_value ? "get" : "set"); return -EINVAL; } sym_buf = (char *)pi->purgatory_buf + sec->sh_offset + sym->st_value; if (get_value) memcpy((void *)buf, sym_buf, size); else memcpy((void *)sym_buf, buf, size); return 0; } #endif /* CONFIG_ARCH_SUPPORTS_KEXEC_PURGATORY */