path: root/kernel/kexec_file.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * kexec: kexec_file_load system call
 *
 * Copyright (C) 2014 Red Hat Inc.
 * Authors:
 *      Vivek Goyal <vgoyal@redhat.com>
 */

#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/memblock.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/fs.h>
#include <linux/ima.h>
#include <crypto/hash.h>
#include <crypto/sha2.h>
#include <linux/elf.h>
#include <linux/elfcore.h>
#include <linux/kernel.h>
#include <linux/kernel_read_file.h>
#include <linux/syscalls.h>
#include <linux/vmalloc.h>
#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;

	kexec_file_dbg_print = false;
}

#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->