Merge branch 'parisc-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux
Pull parisc updates from Helge Deller: - Make the powerpc implementation to read elf files available as a public kexec interface so it can be re-used on other architectures (Sven) - Implement kexec on parisc (Sven) - Add kprobes on ftrace on parisc (Sven) - Fix kernel crash with HSC-PCI cards based on card-mode Dino - Add assembly implementations for memset, strlen, strcpy, strncpy and strcat - Some cleanups, documentation updates, warning fixes, ... * 'parisc-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: (25 commits) parisc: Have git ignore generated real2.S and firmware.c parisc: Disable HP HSC-PCI Cards to prevent kernel crash parisc: add support for kexec_file_load() syscall parisc: wire up kexec_file_load syscall parisc: add kexec syscall support parisc: add __pdc_cpu_rendezvous() kprobes/parisc: remove arch_kprobe_on_func_entry() kexec_elf: support 32 bit ELF files kexec_elf: remove unused variable in kexec_elf_load() kexec_elf: remove Elf_Rel macro kexec_elf: remove PURGATORY_STACK_SIZE kexec_elf: remove parsing of section headers kexec_elf: change order of elf_*_to_cpu() functions kexec: add KEXEC_ELF parisc: Save some bytes in dino driver parisc: Drop comments which are already in pci.h parisc: Convert eisa_enumerator to use pr_cont() parisc: Avoid warning when loading hppb driver parisc: speed up flush_tlb_all_local with qemu parisc: Add ALTERNATIVE_CODE() and ALT_COND_RUN_ON_QEMU ...
This commit is contained in:
Linus Torvalds
@@ -64,6 +64,7 @@ obj-$(CONFIG_CRASH_CORE) += crash_core.o
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obj-$(CONFIG_KEXEC_CORE) += kexec_core.o
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obj-$(CONFIG_KEXEC) += kexec.o
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obj-$(CONFIG_KEXEC_FILE) += kexec_file.o
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obj-$(CONFIG_KEXEC_ELF) += kexec_elf.o
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obj-$(CONFIG_BACKTRACE_SELF_TEST) += backtracetest.o
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obj-$(CONFIG_COMPAT) += compat.o
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obj-$(CONFIG_CGROUPS) += cgroup/
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430
kernel/kexec_elf.c
Normal file
430
kernel/kexec_elf.c
Normal file
@@ -0,0 +1,430 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Load ELF vmlinux file for the kexec_file_load syscall.
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*
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* Copyright (C) 2004 Adam Litke (agl@us.ibm.com)
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* Copyright (C) 2004 IBM Corp.
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* Copyright (C) 2005 R Sharada (sharada@in.ibm.com)
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* Copyright (C) 2006 Mohan Kumar M (mohan@in.ibm.com)
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* Copyright (C) 2016 IBM Corporation
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*
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* Based on kexec-tools' kexec-elf-exec.c and kexec-elf-ppc64.c.
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* Heavily modified for the kernel by
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* Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>.
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*/
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#define pr_fmt(fmt) "kexec_elf: " fmt
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#include <linux/elf.h>
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#include <linux/kexec.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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static inline bool elf_is_elf_file(const struct elfhdr *ehdr)
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{
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return memcmp(ehdr->e_ident, ELFMAG, SELFMAG) == 0;
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}
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static uint64_t elf64_to_cpu(const struct elfhdr *ehdr, uint64_t value)
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{
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if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
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value = le64_to_cpu(value);
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else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
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value = be64_to_cpu(value);
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return value;
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}
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static uint32_t elf32_to_cpu(const struct elfhdr *ehdr, uint32_t value)
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{
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if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
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value = le32_to_cpu(value);
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else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
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value = be32_to_cpu(value);
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return value;
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}
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static uint16_t elf16_to_cpu(const struct elfhdr *ehdr, uint16_t value)
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{
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if (ehdr->e_ident[EI_DATA] == ELFDATA2LSB)
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value = le16_to_cpu(value);
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else if (ehdr->e_ident[EI_DATA] == ELFDATA2MSB)
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value = be16_to_cpu(value);
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return value;
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}
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/**
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* elf_is_ehdr_sane - check that it is safe to use the ELF header
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* @buf_len: size of the buffer in which the ELF file is loaded.
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*/
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static bool elf_is_ehdr_sane(const struct elfhdr *ehdr, size_t buf_len)
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{
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if (ehdr->e_phnum > 0 && ehdr->e_phentsize != sizeof(struct elf_phdr)) {
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pr_debug("Bad program header size.\n");
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return false;
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} else if (ehdr->e_shnum > 0 &&
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ehdr->e_shentsize != sizeof(struct elf_shdr)) {
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pr_debug("Bad section header size.\n");
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return false;
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} else if (ehdr->e_ident[EI_VERSION] != EV_CURRENT ||
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ehdr->e_version != EV_CURRENT) {
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pr_debug("Unknown ELF version.\n");
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return false;
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}
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if (ehdr->e_phoff > 0 && ehdr->e_phnum > 0) {
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size_t phdr_size;
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/*
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* e_phnum is at most 65535 so calculating the size of the
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* program header cannot overflow.
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*/
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phdr_size = sizeof(struct elf_phdr) * ehdr->e_phnum;
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/* Sanity check the program header table location. */
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if (ehdr->e_phoff + phdr_size < ehdr->e_phoff) {
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pr_debug("Program headers at invalid location.\n");
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return false;
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} else if (ehdr->e_phoff + phdr_size > buf_len) {
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pr_debug("Program headers truncated.\n");
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return false;
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}
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}
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if (ehdr->e_shoff > 0 && ehdr->e_shnum > 0) {
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size_t shdr_size;
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/*
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* e_shnum is at most 65536 so calculating
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* the size of the section header cannot overflow.
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*/
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shdr_size = sizeof(struct elf_shdr) * ehdr->e_shnum;
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/* Sanity check the section header table location. */
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if (ehdr->e_shoff + shdr_size < ehdr->e_shoff) {
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pr_debug("Section headers at invalid location.\n");
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return false;
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} else if (ehdr->e_shoff + shdr_size > buf_len) {
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pr_debug("Section headers truncated.\n");
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return false;
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}
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}
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return true;
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}
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static int elf_read_ehdr(const char *buf, size_t len, struct elfhdr *ehdr)
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{
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struct elfhdr *buf_ehdr;
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if (len < sizeof(*buf_ehdr)) {
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pr_debug("Buffer is too small to hold ELF header.\n");
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return -ENOEXEC;
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}
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memset(ehdr, 0, sizeof(*ehdr));
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memcpy(ehdr->e_ident, buf, sizeof(ehdr->e_ident));
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if (!elf_is_elf_file(ehdr)) {
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pr_debug("No ELF header magic.\n");
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return -ENOEXEC;
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}
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if (ehdr->e_ident[EI_CLASS] != ELF_CLASS) {
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pr_debug("Not a supported ELF class.\n");
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return -ENOEXEC;
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} else if (ehdr->e_ident[EI_DATA] != ELFDATA2LSB &&
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ehdr->e_ident[EI_DATA] != ELFDATA2MSB) {
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pr_debug("Not a supported ELF data format.\n");
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return -ENOEXEC;
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}
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buf_ehdr = (struct elfhdr *) buf;
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if (elf16_to_cpu(ehdr, buf_ehdr->e_ehsize) != sizeof(*buf_ehdr)) {
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pr_debug("Bad ELF header size.\n");
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return -ENOEXEC;
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}
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ehdr->e_type = elf16_to_cpu(ehdr, buf_ehdr->e_type);
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ehdr->e_machine = elf16_to_cpu(ehdr, buf_ehdr->e_machine);
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ehdr->e_version = elf32_to_cpu(ehdr, buf_ehdr->e_version);
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ehdr->e_flags = elf32_to_cpu(ehdr, buf_ehdr->e_flags);
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ehdr->e_phentsize = elf16_to_cpu(ehdr, buf_ehdr->e_phentsize);
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ehdr->e_phnum = elf16_to_cpu(ehdr, buf_ehdr->e_phnum);
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ehdr->e_shentsize = elf16_to_cpu(ehdr, buf_ehdr->e_shentsize);
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ehdr->e_shnum = elf16_to_cpu(ehdr, buf_ehdr->e_shnum);
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ehdr->e_shstrndx = elf16_to_cpu(ehdr, buf_ehdr->e_shstrndx);
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switch (ehdr->e_ident[EI_CLASS]) {
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case ELFCLASS64:
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ehdr->e_entry = elf64_to_cpu(ehdr, buf_ehdr->e_entry);
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ehdr->e_phoff = elf64_to_cpu(ehdr, buf_ehdr->e_phoff);
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ehdr->e_shoff = elf64_to_cpu(ehdr, buf_ehdr->e_shoff);
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break;
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case ELFCLASS32:
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ehdr->e_entry = elf32_to_cpu(ehdr, buf_ehdr->e_entry);
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ehdr->e_phoff = elf32_to_cpu(ehdr, buf_ehdr->e_phoff);
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ehdr->e_shoff = elf32_to_cpu(ehdr, buf_ehdr->e_shoff);
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break;
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default:
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pr_debug("Unknown ELF class.\n");
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return -EINVAL;
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}
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return elf_is_ehdr_sane(ehdr, len) ? 0 : -ENOEXEC;
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}
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/**
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* elf_is_phdr_sane - check that it is safe to use the program header
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* @buf_len: size of the buffer in which the ELF file is loaded.
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*/
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static bool elf_is_phdr_sane(const struct elf_phdr *phdr, size_t buf_len)
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{
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if (phdr->p_offset + phdr->p_filesz < phdr->p_offset) {
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pr_debug("ELF segment location wraps around.\n");
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return false;
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} else if (phdr->p_offset + phdr->p_filesz > buf_len) {
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pr_debug("ELF segment not in file.\n");
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return false;
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} else if (phdr->p_paddr + phdr->p_memsz < phdr->p_paddr) {
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pr_debug("ELF segment address wraps around.\n");
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return false;
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}
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return true;
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}
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static int elf_read_phdr(const char *buf, size_t len,
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struct kexec_elf_info *elf_info,
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int idx)
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{
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/* Override the const in proghdrs, we are the ones doing the loading. */
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struct elf_phdr *phdr = (struct elf_phdr *) &elf_info->proghdrs[idx];
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const struct elfhdr *ehdr = elf_info->ehdr;
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const char *pbuf;
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struct elf_phdr *buf_phdr;
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pbuf = buf + elf_info->ehdr->e_phoff + (idx * sizeof(*buf_phdr));
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buf_phdr = (struct elf_phdr *) pbuf;
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phdr->p_type = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_type);
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phdr->p_flags = elf32_to_cpu(elf_info->ehdr, buf_phdr->p_flags);
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switch (ehdr->e_ident[EI_CLASS]) {
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case ELFCLASS64:
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phdr->p_offset = elf64_to_cpu(ehdr, buf_phdr->p_offset);
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phdr->p_paddr = elf64_to_cpu(ehdr, buf_phdr->p_paddr);
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phdr->p_vaddr = elf64_to_cpu(ehdr, buf_phdr->p_vaddr);
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phdr->p_filesz = elf64_to_cpu(ehdr, buf_phdr->p_filesz);
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phdr->p_memsz = elf64_to_cpu(ehdr, buf_phdr->p_memsz);
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phdr->p_align = elf64_to_cpu(ehdr, buf_phdr->p_align);
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break;
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case ELFCLASS32:
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phdr->p_offset = elf32_to_cpu(ehdr, buf_phdr->p_offset);
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phdr->p_paddr = elf32_to_cpu(ehdr, buf_phdr->p_paddr);
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phdr->p_vaddr = elf32_to_cpu(ehdr, buf_phdr->p_vaddr);
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phdr->p_filesz = elf32_to_cpu(ehdr, buf_phdr->p_filesz);
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phdr->p_memsz = elf32_to_cpu(ehdr, buf_phdr->p_memsz);
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phdr->p_align = elf32_to_cpu(ehdr, buf_phdr->p_align);
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break;
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default:
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pr_debug("Unknown ELF class.\n");
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return -EINVAL;
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}
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return elf_is_phdr_sane(phdr, len) ? 0 : -ENOEXEC;
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}
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/**
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* elf_read_phdrs - read the program headers from the buffer
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*
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* This function assumes that the program header table was checked for sanity.
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* Use elf_is_ehdr_sane() if it wasn't.
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||||
*/
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||||
static int elf_read_phdrs(const char *buf, size_t len,
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struct kexec_elf_info *elf_info)
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||||
{
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size_t phdr_size, i;
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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;
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||||
|
||||
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;
|
||||
}
|
||||
Reference in New Issue
Block a user