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![Dave Young](/assets/img/avatar_default.png)
Split kexec_file syscall related code to another file kernel/kexec_file.c so that the #ifdef CONFIG_KEXEC_FILE in kexec.c can be dropped. Sharing variables and functions are moved to kernel/kexec_internal.h per suggestion from Vivek and Petr. [akpm@linux-foundation.org: fix bisectability] [akpm@linux-foundation.org: declare the various arch_kexec functions] [akpm@linux-foundation.org: fix build] Signed-off-by: Dave Young <dyoung@redhat.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Petr Tesarik <ptesarik@suse.cz> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Josh Boyer <jwboyer@fedoraproject.org> Cc: David Howells <dhowells@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1045 lines
25 KiB
C
1045 lines
25 KiB
C
/*
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* kexec: kexec_file_load system call
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*
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* Copyright (C) 2014 Red Hat Inc.
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* Authors:
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* Vivek Goyal <vgoyal@redhat.com>
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*
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* This source code is licensed under the GNU General Public License,
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* Version 2. See the file COPYING for more details.
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*/
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#include <linux/capability.h>
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#include <linux/mm.h>
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#include <linux/file.h>
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#include <linux/slab.h>
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#include <linux/kexec.h>
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#include <linux/mutex.h>
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#include <linux/list.h>
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#include <crypto/hash.h>
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#include <crypto/sha.h>
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#include <linux/syscalls.h>
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#include <linux/vmalloc.h>
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#include "kexec_internal.h"
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/*
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* Declare these symbols weak so that if architecture provides a purgatory,
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* these will be overridden.
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*/
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char __weak kexec_purgatory[0];
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size_t __weak kexec_purgatory_size = 0;
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static int kexec_calculate_store_digests(struct kimage *image);
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static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len)
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{
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struct fd f = fdget(fd);
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int ret;
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struct kstat stat;
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loff_t pos;
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ssize_t bytes = 0;
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if (!f.file)
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return -EBADF;
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ret = vfs_getattr(&f.file->f_path, &stat);
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if (ret)
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goto out;
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if (stat.size > INT_MAX) {
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ret = -EFBIG;
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goto out;
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}
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/* Don't hand 0 to vmalloc, it whines. */
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if (stat.size == 0) {
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ret = -EINVAL;
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goto out;
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}
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*buf = vmalloc(stat.size);
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if (!*buf) {
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ret = -ENOMEM;
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goto out;
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}
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pos = 0;
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while (pos < stat.size) {
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bytes = kernel_read(f.file, pos, (char *)(*buf) + pos,
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stat.size - pos);
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if (bytes < 0) {
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vfree(*buf);
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ret = bytes;
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goto out;
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}
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if (bytes == 0)
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break;
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pos += bytes;
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}
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if (pos != stat.size) {
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ret = -EBADF;
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vfree(*buf);
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goto out;
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}
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*buf_len = pos;
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out:
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fdput(f);
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return ret;
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}
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/* Architectures can provide this probe function */
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int __weak arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
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unsigned long buf_len)
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{
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return -ENOEXEC;
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}
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void * __weak arch_kexec_kernel_image_load(struct kimage *image)
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{
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return ERR_PTR(-ENOEXEC);
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}
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int __weak arch_kimage_file_post_load_cleanup(struct kimage *image)
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{
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return -EINVAL;
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}
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int __weak arch_kexec_kernel_verify_sig(struct kimage *image, void *buf,
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unsigned long buf_len)
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{
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return -EKEYREJECTED;
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}
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/* Apply relocations of type RELA */
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int __weak
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arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
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unsigned int relsec)
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{
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pr_err("RELA relocation unsupported.\n");
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return -ENOEXEC;
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}
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/* Apply relocations of type REL */
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int __weak
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arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs,
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unsigned int relsec)
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{
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pr_err("REL relocation unsupported.\n");
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return -ENOEXEC;
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}
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/*
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* Free up memory used by kernel, initrd, and command line. This is temporary
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* memory allocation which is not needed any more after these buffers have
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* been loaded into separate segments and have been copied elsewhere.
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*/
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void kimage_file_post_load_cleanup(struct kimage *image)
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{
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struct purgatory_info *pi = &image->purgatory_info;
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vfree(image->kernel_buf);
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image->kernel_buf = NULL;
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vfree(image->initrd_buf);
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image->initrd_buf = NULL;
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kfree(image->cmdline_buf);
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image->cmdline_buf = NULL;
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vfree(pi->purgatory_buf);
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pi->purgatory_buf = NULL;
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vfree(pi->sechdrs);
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pi->sechdrs = NULL;
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/* See if architecture has anything to cleanup post load */
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arch_kimage_file_post_load_cleanup(image);
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/*
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* Above call should have called into bootloader to free up
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* any data stored in kimage->image_loader_data. It should
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* be ok now to free it up.
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*/
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kfree(image->image_loader_data);
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image->image_loader_data = NULL;
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}
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/*
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* In file mode list of segments is prepared by kernel. Copy relevant
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* data from user space, do error checking, prepare segment list
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*/
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static int
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kimage_file_prepare_segments(struct kimage *image, int kernel_fd, int initrd_fd,
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const char __user *cmdline_ptr,
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unsigned long cmdline_len, unsigned flags)
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{
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int ret = 0;
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void *ldata;
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ret = copy_file_from_fd(kernel_fd, &image->kernel_buf,
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&image->kernel_buf_len);
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if (ret)
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return ret;
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/* Call arch image probe handlers */
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ret = arch_kexec_kernel_image_probe(image, image->kernel_buf,
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image->kernel_buf_len);
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if (ret)
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goto out;
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#ifdef CONFIG_KEXEC_VERIFY_SIG
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ret = arch_kexec_kernel_verify_sig(image, image->kernel_buf,
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image->kernel_buf_len);
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if (ret) {
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pr_debug("kernel signature verification failed.\n");
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goto out;
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}
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pr_debug("kernel signature verification successful.\n");
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#endif
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/* It is possible that there no initramfs is being loaded */
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if (!(flags & KEXEC_FILE_NO_INITRAMFS)) {
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ret = copy_file_from_fd(initrd_fd, &image->initrd_buf,
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&image->initrd_buf_len);
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if (ret)
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goto out;
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}
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if (cmdline_len) {
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image->cmdline_buf = kzalloc(cmdline_len, GFP_KERNEL);
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if (!image->cmdline_buf) {
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ret = -ENOMEM;
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goto out;
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}
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ret = copy_from_user(image->cmdline_buf, cmdline_ptr,
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cmdline_len);
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if (ret) {
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ret = -EFAULT;
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goto out;
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}
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image->cmdline_buf_len = cmdline_len;
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/* command line should be a string with last byte null */
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if (image->cmdline_buf[cmdline_len - 1] != '\0') {
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ret = -EINVAL;
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goto out;
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}
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}
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/* Call arch image load handlers */
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ldata = arch_kexec_kernel_image_load(image);
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if (IS_ERR(ldata)) {
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ret = PTR_ERR(ldata);
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goto out;
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}
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image->image_loader_data = ldata;
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out:
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/* In case of error, free up all allocated memory in this function */
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if (ret)
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kimage_file_post_load_cleanup(image);
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return ret;
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}
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static int
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kimage_file_alloc_init(struct kimage **rimage, int kernel_fd,
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int initrd_fd, const char __user *cmdline_ptr,
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unsigned long cmdline_len, unsigned long flags)
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{
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int ret;
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struct kimage *image;
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bool kexec_on_panic = flags & KEXEC_FILE_ON_CRASH;
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image = do_kimage_alloc_init();
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if (!image)
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return -ENOMEM;
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image->file_mode = 1;
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if (kexec_on_panic) {
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/* Enable special crash kernel control page alloc policy. */
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image->control_page = crashk_res.start;
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image->type = KEXEC_TYPE_CRASH;
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}
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ret = kimage_file_prepare_segments(image, kernel_fd, initrd_fd,
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cmdline_ptr, cmdline_len, flags);
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if (ret)
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goto out_free_image;
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ret = sanity_check_segment_list(image);
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if (ret)
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goto out_free_post_load_bufs;
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ret = -ENOMEM;
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image->control_code_page = kimage_alloc_control_pages(image,
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get_order(KEXEC_CONTROL_PAGE_SIZE));
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if (!image->control_code_page) {
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pr_err("Could not allocate control_code_buffer\n");
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goto out_free_post_load_bufs;
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}
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if (!kexec_on_panic) {
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image->swap_page = kimage_alloc_control_pages(image, 0);
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if (!image->swap_page) {
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pr_err("Could not allocate swap buffer\n");
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goto out_free_control_pages;
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}
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}
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*rimage = image;
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return 0;
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out_free_control_pages:
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kimage_free_page_list(&image->control_pages);
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out_free_post_load_bufs:
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kimage_file_post_load_cleanup(image);
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out_free_image:
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kfree(image);
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return ret;
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}
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SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
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unsigned long, cmdline_len, const char __user *, cmdline_ptr,
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unsigned long, flags)
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{
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int ret = 0, i;
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struct kimage **dest_image, *image;
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/* We only trust the superuser with rebooting the system. */
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if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
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return -EPERM;
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/* Make sure we have a legal set of flags */
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if (flags != (flags & KEXEC_FILE_FLAGS))
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return -EINVAL;
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image = NULL;
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if (!mutex_trylock(&kexec_mutex))
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return -EBUSY;
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dest_image = &kexec_image;
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if (flags & KEXEC_FILE_ON_CRASH)
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dest_image = &kexec_crash_image;
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if (flags & KEXEC_FILE_UNLOAD)
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goto exchange;
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/*
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* In case of crash, new kernel gets loaded in reserved region. It is
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* same memory where old crash kernel might be loaded. Free any
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* current crash dump kernel before we corrupt it.
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*/
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if (flags & KEXEC_FILE_ON_CRASH)
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kimage_free(xchg(&kexec_crash_image, NULL));
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ret = kimage_file_alloc_init(&image, kernel_fd, initrd_fd, cmdline_ptr,
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cmdline_len, flags);
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if (ret)
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goto out;
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ret = machine_kexec_prepare(image);
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if (ret)
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goto out;
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ret = kexec_calculate_store_digests(image);
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if (ret)
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goto out;
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for (i = 0; i < image->nr_segments; i++) {
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struct kexec_segment *ksegment;
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ksegment = &image->segment[i];
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pr_debug("Loading segment %d: buf=0x%p bufsz=0x%zx mem=0x%lx memsz=0x%zx\n",
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i, ksegment->buf, ksegment->bufsz, ksegment->mem,
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ksegment->memsz);
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ret = kimage_load_segment(image, &image->segment[i]);
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if (ret)
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goto out;
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}
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kimage_terminate(image);
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/*
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* Free up any temporary buffers allocated which are not needed
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* after image has been loaded
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*/
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kimage_file_post_load_cleanup(image);
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exchange:
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image = xchg(dest_image, image);
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out:
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mutex_unlock(&kexec_mutex);
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kimage_free(image);
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return ret;
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}
|
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static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
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struct kexec_buf *kbuf)
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{
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struct kimage *image = kbuf->image;
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unsigned long temp_start, temp_end;
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temp_end = min(end, kbuf->buf_max);
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temp_start = temp_end - kbuf->memsz;
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do {
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/* align down start */
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temp_start = temp_start & (~(kbuf->buf_align - 1));
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if (temp_start < start || temp_start < kbuf->buf_min)
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return 0;
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temp_end = temp_start + kbuf->memsz - 1;
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|
|
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/*
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* Make sure this does not conflict with any of existing
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* segments
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*/
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if (kimage_is_destination_range(image, temp_start, temp_end)) {
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temp_start = temp_start - PAGE_SIZE;
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continue;
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}
|
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|
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/* We found a suitable memory range */
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break;
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} while (1);
|
|
|
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/* If we are here, we found a suitable memory range */
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kbuf->mem = temp_start;
|
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|
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/* Success, stop navigating through remaining System RAM ranges */
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return 1;
|
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}
|
|
|
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static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
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struct kexec_buf *kbuf)
|
|
{
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struct kimage *image = kbuf->image;
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unsigned long temp_start, temp_end;
|
|
|
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temp_start = max(start, kbuf->buf_min);
|
|
|
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do {
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temp_start = ALIGN(temp_start, kbuf->buf_align);
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temp_end = temp_start + kbuf->memsz - 1;
|
|
|
|
if (temp_end > end || temp_end > kbuf->buf_max)
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return 0;
|
|
/*
|
|
* Make sure this does not conflict with any of existing
|
|
* segments
|
|
*/
|
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if (kimage_is_destination_range(image, temp_start, temp_end)) {
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|
temp_start = temp_start + PAGE_SIZE;
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|
continue;
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}
|
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|
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/* We found a suitable memory range */
|
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break;
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} while (1);
|
|
|
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/* If we are here, we found a suitable memory range */
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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;
|
|
}
|