Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Load ELF vmlinux file for the kexec_file_load syscall.
 *
 * Copyright (C) 2004  Adam Litke (agl@us.ibm.com)
 * Copyright (C) 2004  IBM Corp.
 * Copyright (C) 2005  R Sharada (sharada@in.ibm.com)
 * Copyright (C) 2006  Mohan Kumar M (mohan@in.ibm.com)
 * Copyright (C) 2016  IBM Corporation
 *
 * Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c.
 * Heavily modified for the kernel by
 * Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
 */
 
#define pr_fmt(fmt)	"kexec_elf: " fmt
 
#include <linux/elf.h>
#include <linux/kexec.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
 
static inline bool elf_is_elf_file(const struct elfhdr *ehdr)
{
<------>return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0;
}
 
static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value)
{
<------>if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
<------><------>value = le64_to_cpu(value);
<------>else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
<------><------>value = be64_to_cpu(value);
 
<------>return value;
}
 
static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value)
{
<------>if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
<------><------>value = le32_to_cpu(value);
<------>else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
<------><------>value = be32_to_cpu(value);
 
<------>return value;
}
 
static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value)
{
<------>if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
<------><------>value = le16_to_cpu(value);
<------>else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
<------><------>value = be16_to_cpu(value);
 
<------>return value;
}
 
/**
 * elf_is_ehdr_sane - check that it is safe to use the ELF header
 * @buf_len:	size of the buffer in which the ELF file is loaded.
 */
static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len)
{
<------>if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) {
<------><------>pr_debug("Bad program header size.\n");
<------><------>return false;
<------>} else if (ehdr->e_shnum > 0 &&
<------><------>   ehdr->e_shentsize != sizeof(struct elf_shdr)) {
<------><------>pr_debug("Bad section header size.\n");
<------><------>return false;
<------>} else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT ||
<------><------>   ehdr->e_version != EV_CURRENT) {
<------><------>pr_debug("Unknown ELF version.\n");
<------><------>return false;
<------>}
 
<------>if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
<------><------>size_t phdr_size;
 
<------><------>/*
<------><------> * e_phnum is at most 65535 so calculating the size of the
<------><------> * program header cannot overflow.
<------><------> */
<------><------>phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum;
 
<------><------>/* Sanity check the program header table location. */
<------><------>if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) {
<------><------><------>pr_debug("Program headers at invalid location.\n");
<------><------><------>return false;
<------><------>} else if (ehdr->e_phoff + phdr_size > buf_len) {
<------><------><------>pr_debug("Program headers truncated.\n");
<------><------><------>return false;
<------><------>}
<------>}
 
<------>if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) {
<------><------>size_t shdr_size;
 
<------><------>/*
<------><------> * e_shnum is at most 65536 so calculating
<------><------> * the size of the section header cannot overflow.
<------><------> */
<------><------>shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum;
 
<------><------>/* Sanity check the section header table location. */
<------><------>if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) {
<------><------><------>pr_debug("Section headers at invalid location.\n");
<------><------><------>return false;
<------><------>} else if (ehdr->e_shoff + shdr_size > buf_len) {
<------><------><------>pr_debug("Section headers truncated.\n");
<------><------><------>return false;
<------><------>}
<------>}
 
<------>return true;
}
 
static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
{
<------>struct elfhdr *buf_ehdr;
 
<------>if (len < sizeof(*buf_ehdr)) {
<------><------>pr_debug("Buffer is too small to hold ELF header.\n");
<------><------>return -ENOEXEC;
<------>}
 
<------>memset(ehdr, 0, sizeof(*ehdr));
<------>memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident));
<------>if (!elf_is_elf_file(ehdr)) {
<------><------>pr_debug("No ELF header magic.\n");
<------><------>return -ENOEXEC;
<------>}
 
<------>if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) {
<------><------>pr_debug("Not a supported ELF class.\n");
<------><------>return -ENOEXEC;
<------>} else  if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB &&
<------><------>ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
<------><------>pr_debug("Not a supported ELF data format.\n");
<------><------>return -ENOEXEC;
<------>}
 
<------>buf_ehdr = (struct elfhdr *) buf;
<------>if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) {
<------><------>pr_debug("Bad ELF header size.\n");
<------><------>return -ENOEXEC;
<------>}
 
<------>ehdr->e_type      = elf16_to_cpu(ehdr, buf_ehdr->e_type);
<------>ehdr->e_machine   = elf16_to_cpu(ehdr, buf_ehdr->e_machine);
<------>ehdr->e_version   = elf32_to_cpu(ehdr, buf_ehdr->e_version);
<------>ehdr->e_flags     = elf32_to_cpu(ehdr, buf_ehdr->e_flags);
<------>ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize);
<------>ehdr->e_phnum     = elf16_to_cpu(ehdr, buf_ehdr->e_phnum);
<------>ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize);
<------>ehdr->e_shnum     = elf16_to_cpu(ehdr, buf_ehdr->e_shnum);
<------>ehdr->e_shstrndx  = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx);
 
<------>switch (ehdr->e_ident[EI_CLASS]) {
<------>case ELFCLASS64:
<------><------>ehdr->e_entry = elf64_to_cpu(ehdr, buf_ehdr->e_entry);
<------><------>ehdr->e_phoff = elf64_to_cpu(ehdr, buf_ehdr->e_phoff);
<------><------>ehdr->e_shoff = elf64_to_cpu(ehdr, buf_ehdr->e_shoff);
<------><------>break;
 
<------>case ELFCLASS32:
<------><------>ehdr->e_entry = elf32_to_cpu(ehdr, buf_ehdr->e_entry);
<------><------>ehdr->e_phoff = elf32_to_cpu(ehdr, buf_ehdr->e_phoff);
<------><------>ehdr->e_shoff = elf32_to_cpu(ehdr, buf_ehdr->e_shoff);
<------><------>break;
 
<------>default:
<------><------>pr_debug("Unknown ELF class.\n");
<------><------>return -EINVAL;
<------>}
 
<------>return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC;
}
 
/**
 * elf_is_phdr_sane - check that it is safe to use the program header
 * @buf_len:	size of the buffer in which the ELF file is loaded.
 */
static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len)
{
 
<------>if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) {
<------><------>pr_debug("ELF segment location wraps around.\n");
<------><------>return false;
<------>} else if (phdr->p_offset + phdr->p_filesz > buf_len) {
<------><------>pr_debug("ELF segment not in file.\n");
<------><------>return false;
<------>} else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) {
<------><------>pr_debug("ELF segment address wraps around.\n");
<------><------>return false;
<------>}
 
<------>return true;
}
 
static int elf_read_phdr(const char *buf, size_t len,
<------><------><------> struct kexec_elf_info *elf_info,
<------><------><------> int idx)
{
<------>/* Override the const in proghdrs, we are the ones doing the loading. */
<------>struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx];
<------>const struct elfhdr *ehdr = elf_info->ehdr;
<------>const char *pbuf;
<------>struct elf_phdr *buf_phdr;
 
<------>pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr));
<------>buf_phdr = (struct elf_phdr *) pbuf;
 
<------>phdr->p_type   = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type);
<------>phdr->p_flags  = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags);
 
<------>switch (ehdr->e_ident[EI_CLASS]) {
<------>case ELFCLASS64:
<------><------>phdr->p_offset = elf64_to_cpu(ehdr, buf_phdr->p_offset);
<------><------>phdr->p_paddr  = elf64_to_cpu(ehdr, buf_phdr->p_paddr);
<------><------>phdr->p_vaddr  = elf64_to_cpu(ehdr, buf_phdr->p_vaddr);
<------><------>phdr->p_filesz = elf64_to_cpu(ehdr, buf_phdr->p_filesz);
<------><------>phdr->p_memsz  = elf64_to_cpu(ehdr, buf_phdr->p_memsz);
<------><------>phdr->p_align  = elf64_to_cpu(ehdr, buf_phdr->p_align);
<------><------>break;
 
<------>case ELFCLASS32:
<------><------>phdr->p_offset = elf32_to_cpu(ehdr, buf_phdr->p_offset);
<------><------>phdr->p_paddr  = elf32_to_cpu(ehdr, buf_phdr->p_paddr);
<------><------>phdr->p_vaddr  = elf32_to_cpu(ehdr, buf_phdr->p_vaddr);
<------><------>phdr->p_filesz = elf32_to_cpu(ehdr, buf_phdr->p_filesz);
<------><------>phdr->p_memsz  = elf32_to_cpu(ehdr, buf_phdr->p_memsz);
<------><------>phdr->p_align  = elf32_to_cpu(ehdr, buf_phdr->p_align);
<------><------>break;
 
<------>default:
<------><------>pr_debug("Unknown ELF class.\n");
<------><------>return -EINVAL;
<------>}
 
<------>return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC;
}
 
/**
 * elf_read_phdrs - read the program headers from the buffer
 *
 * This function assumes that the program header table was checked for sanity.
 * Use elf_is_ehdr_sane() if it wasn't.
 */
static int elf_read_phdrs(const char *buf, size_t len,
<------><------><------>  struct kexec_elf_info *elf_info)
{
<------>size_t phdr_size, i;
<------>const struct elfhdr *ehdr = elf_info->ehdr;
 
<------>/*
<------> * e_phnum is at most 65535 so calculating the size of the
<------> * program header cannot overflow.
<------> */
<------>phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum;
 
<------>elf_info->proghdrs = kzalloc(phdr_size, GFP_KERNEL);
<------>if (!elf_info->proghdrs)
<------><------>return -ENOMEM;
 
<------>for (i = 0; i < ehdr->e_phnum; i++) {
<------><------>int ret;
 
<------><------>ret = elf_read_phdr(buf, len, elf_info, i);
<------><------>if (ret) {
<------><------><------>kfree(elf_info->proghdrs);
<------><------><------>elf_info->proghdrs = NULL;
<------><------><------>return ret;
<------><------>}
<------>}
 
<------>return 0;
}
 
/**
 * elf_read_from_buffer - read ELF file and sets up ELF header and ELF info
 * @buf:	Buffer to read ELF file from.
 * @len:	Size of @buf.
 * @ehdr:	Pointer to existing struct which will be populated.
 * @elf_info:	Pointer to existing struct which will be populated.
 *
 * This function allows reading ELF files with different byte order than
 * the kernel, byte-swapping the fields as needed.
 *
 * Return:
 * On success returns 0, and the caller should call
 * kexec_free_elf_info(elf_info) to free the memory allocated for the section
 * and program headers.
 */
static int elf_read_from_buffer(const char *buf, size_t len,
<------><------><------><------>struct elfhdr *ehdr,
<------><------><------><------>struct kexec_elf_info *elf_info)
{
<------>int ret;
 
<------>ret = elf_read_ehdr(buf, len, ehdr);
<------>if (ret)
<------><------>return ret;
 
<------>elf_info->buffer = buf;
<------>elf_info->ehdr = ehdr;
<------>if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
<------><------>ret = elf_read_phdrs(buf, len, elf_info);
<------><------>if (ret)
<------><------><------>return ret;
<------>}
<------>return 0;
}
 
/**
 * kexec_free_elf_info - free memory allocated by elf_read_from_buffer
 */
void kexec_free_elf_info(struct kexec_elf_info *elf_info)
{
<------>kfree(elf_info->proghdrs);
<------>memset(elf_info, 0, sizeof(*elf_info));
}
/**
 * kexec_build_elf_info - read ELF executable and check that we can use it
 */
int kexec_build_elf_info(const char *buf, size_t len, struct elfhdr *ehdr,
<------><------><------>       struct kexec_elf_info *elf_info)
{
<------>int i;
<------>int ret;
 
<------>ret = elf_read_from_buffer(buf, len, ehdr, elf_info);
<------>if (ret)
<------><------>return ret;
 
<------>/* Big endian vmlinux has type ET_DYN. */
<------>if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN) {
<------><------>pr_err("Not an ELF executable.\n");
<------><------>goto error;
<------>} else if (!elf_info->proghdrs) {
<------><------>pr_err("No ELF program header.\n");
<------><------>goto error;
<------>}
 
<------>for (i = 0; i < ehdr->e_phnum; i++) {
<------><------>/*
<------><------> * Kexec does not support loading interpreters.
<------><------> * In addition this check keeps us from attempting
<------><------> * to kexec ordinay executables.
<------><------> */
<------><------>if (elf_info->proghdrs[i].p_type == PT_INTERP) {
<------><------><------>pr_err("Requires an ELF interpreter.\n");
<------><------><------>goto error;
<------><------>}
<------>}
 
<------>return 0;
error:
<------>kexec_free_elf_info(elf_info);
<------>return -ENOEXEC;
}
 
 
int kexec_elf_probe(const char *buf, unsigned long len)
{
<------>struct elfhdr ehdr;
<------>struct kexec_elf_info elf_info;
<------>int ret;
 
<------>ret = kexec_build_elf_info(buf, len, &ehdr, &elf_info);
<------>if (ret)
<------><------>return ret;
 
<------>kexec_free_elf_info(&elf_info);
 
<------>return elf_check_arch(&ehdr) ? 0 : -ENOEXEC;
}
 
/**
 * kexec_elf_load - load ELF executable image
 * @lowest_load_addr:	On return, will be the address where the first PT_LOAD
 *			section will be loaded in memory.
 *
 * Return:
 * 0 on success, negative value on failure.
 */
int kexec_elf_load(struct kimage *image, struct elfhdr *ehdr,
<------><------><------> struct kexec_elf_info *elf_info,
<------><------><------> struct kexec_buf *kbuf,
<------><------><------> unsigned long *lowest_load_addr)
{
<------>unsigned long lowest_addr = UINT_MAX;
<------>int ret;
<------>size_t i;
 
<------>/* Read in the PT_LOAD segments. */
<------>for (i = 0; i < ehdr->e_phnum; i++) {
<------><------>unsigned long load_addr;
<------><------>size_t size;
<------><------>const struct elf_phdr *phdr;
 
<------><------>phdr = &elf_info->proghdrs[i];
<------><------>if (phdr->p_type != PT_LOAD)
<------><------><------>continue;
 
<------><------>size = phdr->p_filesz;
<------><------>if (size > phdr->p_memsz)
<------><------><------>size = phdr->p_memsz;
 
<------><------>kbuf->buffer = (void *) elf_info->buffer + phdr->p_offset;
<------><------>kbuf->bufsz = size;
<------><------>kbuf->memsz = phdr->p_memsz;
<------><------>kbuf->buf_align = phdr->p_align;
<------><------>kbuf->buf_min = phdr->p_paddr;
<------><------>kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
<------><------>ret = kexec_add_buffer(kbuf);
<------><------>if (ret)
<------><------><------>goto out;
<------><------>load_addr = kbuf->mem;
 
<------><------>if (load_addr < lowest_addr)
<------><------><------>lowest_addr = load_addr;
<------>}
 
<------>*lowest_load_addr = lowest_addr;
<------>ret = 0;
 out:
<------>return ret;
}