| /* |
| * kexec: kexec_file_load system call |
| * |
| * Copyright (C) 2014 Red Hat Inc. |
| * Authors: |
| * Vivek Goyal <vgoyal@redhat.com> |
| * |
| * This source code is licensed under the GNU General Public License, |
| * Version 2. See the file COPYING for more details. |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/capability.h> |
| #include <linux/mm.h> |
| #include <linux/file.h> |
| #include <linux/slab.h> |
| #include <linux/kexec.h> |
| #include <linux/mutex.h> |
| #include <linux/list.h> |
| #include <crypto/hash.h> |
| #include <crypto/sha.h> |
| #include <linux/syscalls.h> |
| #include <linux/vmalloc.h> |
| #include "kexec_internal.h" |
| |
| /* |
| * Declare these symbols weak so that if architecture provides a purgatory, |
| * these will be overridden. |
| */ |
| char __weak kexec_purgatory[0]; |
| size_t __weak kexec_purgatory_size = 0; |
| |
| static int kexec_calculate_store_digests(struct kimage *image); |
| |
| static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len) |
| { |
| struct fd f = fdget(fd); |
| int ret; |
| struct kstat stat; |
| loff_t pos; |
| ssize_t bytes = 0; |
| |
| if (!f.file) |
| return -EBADF; |
| |
| ret = vfs_getattr(&f.file->f_path, &stat); |
| if (ret) |
| goto out; |
| |
| if (stat.size > INT_MAX) { |
| ret = -EFBIG; |
| goto out; |
| } |
| |
| /* Don't hand 0 to vmalloc, it whines. */ |
| if (stat.size == 0) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| *buf = vmalloc(stat.size); |
| if (!*buf) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| pos = 0; |
| while (pos < stat.size) { |
| bytes = kernel_read(f.file, pos, (char *)(*buf) + pos, |
| stat.size - pos); |
| if (bytes < 0) { |
| vfree(*buf); |
| ret = bytes; |
| goto out; |
| } |
| |
| if (bytes == 0) |
| break; |
| pos += bytes; |
| } |
| |
| if (pos != stat.size) { |
| ret = -EBADF; |
| vfree(*buf); |
| goto out; |
| } |
| |
| *buf_len = pos; |
| out: |
| fdput(f); |
| return ret; |
| } |
| |
| /* Architectures can provide this probe function */ |
| int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf, |
| unsigned long buf_len) |
| { |
| return -ENOEXEC; |
| } |
| |
| void * __weak arch_kexec_kernel_image_load(struct kimage *image) |
| { |
| return ERR_PTR(-ENOEXEC); |
| } |
| |
| int __weak arch_kimage_file_post_load_cleanup(struct kimage *image) |
| { |
| return -EINVAL; |
| } |
| |
| #ifdef CONFIG_KEXEC_VERIFY_SIG |
| int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf, |
| unsigned long buf_len) |
| { |
| return -EKEYREJECTED; |
| } |
| #endif |
| |
| /* Apply relocations of type RELA */ |
| int __weak |
| arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, |
| unsigned int relsec) |
| { |
| pr_err("RELA relocation unsupported.\n"); |
| return -ENOEXEC; |
| } |
| |
| /* Apply relocations of type REL */ |
| int __weak |
| arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, |
| unsigned int relsec) |
| { |
| pr_err("REL relocation unsupported.\n"); |
| return -ENOEXEC; |
| } |
| |
| /* |
| * 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; |
| |
| /* 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; |
| } |
| |
| /* |
| * 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) |
| { |
| int ret = 0; |
| void *ldata; |
| |
| ret = copy_file_from_fd(kernel_fd, &image->kernel_buf, |
| &image->kernel_buf_len); |
| if (ret) |
| return 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_VERIFY_SIG |
| ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf, |
| image->kernel_buf_len); |
| if (ret) { |
| pr_debug("kernel signature verification failed.\n"); |
| goto out; |
| } |
| pr_debug("kernel signature verification successful.\n"); |
| #endif |
| /* It is possible that there no initramfs is being loaded */ |
| if (!(flags & KEXEC_FILE_NO_INITRAMFS)) { |
| ret = copy_file_from_fd(initrd_fd, &image->initrd_buf, |
| &image->initrd_buf_len); |
| if (ret) |
| goto out; |
| } |
| |
| if (cmdline_len) { |
| image->cmdline_buf = kzalloc(cmdline_len, GFP_KERNEL); |
| if (!image->cmdline_buf) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| ret = copy_from_user(image->cmdline_buf, cmdline_ptr, |
| cmdline_len); |
| if (ret) { |
| ret = -EFAULT; |
| 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; |
| } |
| } |
| |
| /* Call arch image load handlers */ |
| ldata = arch_kexec_kernel_image_load(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 ret = 0, i; |
| struct kimage **dest_image, *image; |
| |
| /* We only trust the superuser with rebooting the system. */ |
| if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) |
| return -EPERM; |
| |
| /* Make sure we have a legal set of flags */ |
| if (flags != (flags & KEXEC_FILE_FLAGS)) |
| return -EINVAL; |
| |
| image = NULL; |
| |
| if (!mutex_trylock(&kexec_mutex)) |
| return -EBUSY; |
| |
| dest_image = &kexec_image; |
| if (flags & KEXEC_FILE_ON_CRASH) |
| dest_image = &kexec_crash_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; |
| |
| 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); |
| |
| /* |
| * 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: |
| mutex_unlock(&kexec_mutex); |
| 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(u64 start, u64 end, void *arg) |
| { |
| struct kexec_buf *kbuf = (struct kexec_buf *)arg; |
| unsigned long sz = end - start + 1; |
| |
| /* Returning 0 will take to next memory range */ |
| 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); |
| } |
| |
| /* |
| * Helper function for placing a buffer in a kexec segment. This assumes |
| * that kexec_mutex is held. |
| */ |
| int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz, |
| unsigned long memsz, unsigned long buf_align, |
| unsigned long buf_min, unsigned long buf_max, |
| bool top_down, unsigned long *load_addr) |
| { |
| |
| struct kexec_segment *ksegment; |
| struct kexec_buf buf, *kbuf; |
| int ret; |
| |
| /* Currently adding segment this way is allowed only in file mode */ |
| if (!image->file_mode) |
| return -EINVAL; |
| |
| if (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(&image->control_pages)) { |
| WARN_ON(1); |
| return -EINVAL; |
| } |
| |
| memset(&buf, 0, sizeof(struct kexec_buf)); |
| kbuf = &buf; |
| kbuf->image = image; |
| kbuf->buffer = buffer; |
| kbuf->bufsz = bufsz; |
| |
| kbuf->memsz = ALIGN(memsz, PAGE_SIZE); |
| kbuf->buf_align = max(buf_align, PAGE_SIZE); |
| kbuf->buf_min = buf_min; |
| kbuf->buf_max = buf_max; |
| kbuf->top_down = top_down; |
| |
| /* Walk the RAM ranges and allocate a suitable range for the buffer */ |
| if (image->type == KEXEC_TYPE_CRASH) |
| ret = walk_iomem_res("Crash kernel", |
| IORESOURCE_MEM | IORESOURCE_BUSY, |
| crashk_res.start, crashk_res.end, kbuf, |
| locate_mem_hole_callback); |
| else |
| ret = walk_system_ram_res(0, -1, kbuf, |
| locate_mem_hole_callback); |
| if (ret != 1) { |
| /* A suitable memory range could not be found for buffer */ |
| return -EADDRNOTAVAIL; |
| } |
| |
| /* Found a suitable memory range */ |
| ksegment = &image->segment[image->nr_segments]; |
| ksegment->kbuf = kbuf->buffer; |
| ksegment->bufsz = kbuf->bufsz; |
| ksegment->mem = kbuf->mem; |
| ksegment->memsz = kbuf->memsz; |
| image->nr_segments++; |
| *load_addr = ksegment->mem; |
| 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; |
| |
| 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) |
| goto out_free_desc; |
| |
| desc->tfm = tfm; |
| desc->flags = 0; |
| |
| 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; |
| |
| 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, "sha_regions", |
| sha_regions, sha_region_sz, 0); |
| if (ret) |
| goto out_free_digest; |
| |
| ret = kexec_purgatory_get_set_symbol(image, "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; |
| } |
| |
| /* Actually load purgatory. Lot of code taken from kexec-tools */ |
| static int __kexec_load_purgatory(struct kimage *image, unsigned long min, |
| unsigned long max, int top_down) |
| { |
| struct purgatory_info *pi = &image->purgatory_info; |
| unsigned long align, buf_align, bss_align, buf_sz, bss_sz, bss_pad; |
| unsigned long memsz, entry, load_addr, curr_load_addr, bss_addr, offset; |
| unsigned char *buf_addr, *src; |
| int i, ret = 0, entry_sidx = -1; |
| const Elf_Shdr *sechdrs_c; |
| Elf_Shdr *sechdrs = NULL; |
| void *purgatory_buf = NULL; |
| |
| /* |
| * sechdrs_c points to section headers in purgatory and are read |
| * only. No modifications allowed. |
| */ |
| sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff; |
| |
| /* |
| * We can not modify sechdrs_c[] and its fields. It is read only. |
| * Copy it over to a local copy where one can store some temporary |
| * data and free it at the end. We need to modify ->sh_addr and |
| * ->sh_offset fields to keep track of permanent and temporary |
| * locations of sections. |
| */ |
| sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr)); |
| if (!sechdrs) |
| return -ENOMEM; |
| |
| memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr)); |
| |
| /* |
| * We seem to have multiple copies of sections. First copy is which |
| * is embedded in kernel in read only section. Some of these sections |
| * will be copied to a temporary buffer and relocated. And these |
| * sections will finally be copied to their final destination at |
| * segment load time. |
| * |
| * Use ->sh_offset to reflect section address in memory. It will |
| * point to original read only copy if section is not allocatable. |
| * Otherwise it will point to temporary copy which will be relocated. |
| * |
| * Use ->sh_addr to contain final address of the section where it |
| * will go during execution time. |
| */ |
| for (i = 0; i < pi->ehdr->e_shnum; i++) { |
| if (sechdrs[i].sh_type == SHT_NOBITS) |
| continue; |
| |
| sechdrs[i].sh_offset = (unsigned long)pi->ehdr + |
| sechdrs[i].sh_offset; |
| } |
| |
| /* |
| * Identify entry point section and make entry relative to section |
| * start. |
| */ |
| entry = pi->ehdr->e_entry; |
| for (i = 0; i < pi->ehdr->e_shnum; i++) { |
| if (!(sechdrs[i].sh_flags & SHF_ALLOC)) |
| continue; |
| |
| if (!(sechdrs[i].sh_flags & SHF_EXECINSTR)) |
| continue; |
| |
| /* Make entry section relative */ |
| if (sechdrs[i].sh_addr <= pi->ehdr->e_entry && |
| ((sechdrs[i].sh_addr + sechdrs[i].sh_size) > |
| pi->ehdr->e_entry)) { |
| entry_sidx = i; |
| entry -= sechdrs[i].sh_addr; |
| break; |
| } |
| } |
| |
| /* Determine how much memory is needed to load relocatable object. */ |
| buf_align = 1; |
| bss_align = 1; |
| buf_sz = 0; |
| 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 (buf_align < align) |
| buf_align = align; |
| buf_sz = ALIGN(buf_sz, align); |
| buf_sz += sechdrs[i].sh_size; |
| } else { |
| /* bss section */ |
| if (bss_align < align) |
| bss_align = align; |
| bss_sz = ALIGN(bss_sz, align); |
| bss_sz += sechdrs[i].sh_size; |
| } |
| } |
| |
| /* Determine the bss padding required to align bss properly */ |
| bss_pad = 0; |
| if (buf_sz & (bss_align - 1)) |
| bss_pad = bss_align - (buf_sz & (bss_align - 1)); |
| |
| memsz = buf_sz + bss_pad + bss_sz; |
| |
| /* Allocate buffer for purgatory */ |
| purgatory_buf = vzalloc(buf_sz); |
| if (!purgatory_buf) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| |
| if (buf_align < bss_align) |
| buf_align = bss_align; |
| |
| /* Add buffer to segment list */ |
| ret = kexec_add_buffer(image, purgatory_buf, buf_sz, memsz, |
| buf_align, min, max, top_down, |
| &pi->purgatory_load_addr); |
| if (ret) |
| goto out; |
| |
| /* Load SHF_ALLOC sections */ |
| buf_addr = purgatory_buf; |
| load_addr = curr_load_addr = pi->purgatory_load_addr; |
| bss_addr = load_addr + buf_sz + bss_pad; |
| |
| 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) { |
| curr_load_addr = ALIGN(curr_load_addr, align); |
| offset = curr_load_addr - load_addr; |
| /* We already modifed ->sh_offset to keep src addr */ |
| src = (char *) sechdrs[i].sh_offset; |
| memcpy(buf_addr + offset, src, sechdrs[i].sh_size); |
| |
| /* Store load address and source address of section */ |
| sechdrs[i].sh_addr = curr_load_addr; |
| |
| /* |
| * This section got copied to temporary buffer. Update |
| * ->sh_offset accordingly. |
| */ |
| sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset); |
| |
| /* Advance to the next address */ |
| curr_load_addr += sechdrs[i].sh_size; |
| } else { |
| bss_addr = ALIGN(bss_addr, align); |
| sechdrs[i].sh_addr = bss_addr; |
| bss_addr += sechdrs[i].sh_size; |
| } |
| } |
| |
| /* Update entry point based on load address of text section */ |
| if (entry_sidx >= 0) |
| entry += sechdrs[entry_sidx].sh_addr; |
| |
| /* Make kernel jump to purgatory after shutdown */ |
| image->start = entry; |
| |
| /* Used later to get/set symbol values */ |
| pi->sechdrs = sechdrs; |
| |
| /* |
| * Used later to identify which section is purgatory and skip it |
| * from checksumming. |
| */ |
| pi->purgatory_buf = purgatory_buf; |
| return ret; |
| out: |
| vfree(sechdrs); |
| vfree(purgatory_buf); |
| return ret; |
| } |
| |
| static int kexec_apply_relocations(struct kimage *image) |
| { |
| int i, ret; |
| struct purgatory_info *pi = &image->purgatory_info; |
| Elf_Shdr *sechdrs = pi->sechdrs; |
| |
| /* Apply relocations */ |
| for (i = 0; i < pi->ehdr->e_shnum; i++) { |
| Elf_Shdr *section, *symtab; |
| |
| if (sechdrs[i].sh_type != SHT_RELA && |
| sechdrs[i].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 (sechdrs[i].sh_info >= pi->ehdr->e_shnum || |
| sechdrs[i].sh_link >= pi->ehdr->e_shnum) |
| return -ENOEXEC; |
| |
| section = &sechdrs[sechdrs[i].sh_info]; |
| symtab = &sechdrs[sechdrs[i].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 (sechdrs[i].sh_type == SHT_RELA) |
| ret = arch_kexec_apply_relocations_add(pi->ehdr, |
| sechdrs, i); |
| else if (sechdrs[i].sh_type == SHT_REL) |
| ret = arch_kexec_apply_relocations(pi->ehdr, |
| sechdrs, i); |
| if (ret) |
| return ret; |
| } |
| |
| return 0; |
| } |
| |
| /* Load relocatable purgatory object and relocate it appropriately */ |
| int kexec_load_purgatory(struct kimage *image, unsigned long min, |
| unsigned long max, int top_down, |
| unsigned long *load_addr) |
| { |
| struct purgatory_info *pi = &image->purgatory_info; |
| int ret; |
| |
| if (kexec_purgatory_size <= 0) |
| return -EINVAL; |
| |
| if (kexec_purgatory_size < sizeof(Elf_Ehdr)) |
| return -ENOEXEC; |
| |
| pi->ehdr = (Elf_Ehdr *)kexec_purgatory; |
| |
| if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0 |
| || pi->ehdr->e_type != ET_REL |
| || !elf_check_arch(pi->ehdr) |
| || pi->ehdr->e_shentsize != sizeof(Elf_Shdr)) |
| return -ENOEXEC; |
| |
| if (pi->ehdr->e_shoff >= kexec_purgatory_size |
| || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) > |
| kexec_purgatory_size - pi->ehdr->e_shoff)) |
| return -ENOEXEC; |
| |
| ret = __kexec_load_purgatory(image, min, max, top_down); |
| if (ret) |
| return ret; |
| |
| ret = kexec_apply_relocations(image); |
| if (ret) |
| goto out; |
| |
| *load_addr = pi->purgatory_load_addr; |
| return 0; |
| out: |
| vfree(pi->sechdrs); |
| vfree(pi->purgatory_buf); |
| return ret; |
| } |
| |
| static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, |
| const char *name) |
| { |
| Elf_Sym *syms; |
| Elf_Shdr *sechdrs; |
| Elf_Ehdr *ehdr; |
| int i, k; |
| const char *strtab; |
| |
| if (!pi->sechdrs || !pi->ehdr) |
| return NULL; |
| |
| sechdrs = pi->sechdrs; |
| ehdr = pi->ehdr; |
| |
| 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 = (char *)sechdrs[sechdrs[i].sh_link].sh_offset; |
| syms = (Elf_Sym *)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; |
| 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) |
| { |
| Elf_Sym *sym; |
| Elf_Shdr *sechdrs; |
| struct purgatory_info *pi = &image->purgatory_info; |
| 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; |
| } |
| |
| sechdrs = pi->sechdrs; |
| |
| if (sechdrs[sym->st_shndx].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 = (unsigned char *)sechdrs[sym->st_shndx].sh_offset + |
| sym->st_value; |
| |
| if (get_value) |
| memcpy((void *)buf, sym_buf, size); |
| else |
| memcpy((void *)sym_buf, buf, size); |
| |
| return 0; |
| } |