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// SPDX-License-Identifier: GPL-2.0
/*
* ELF loader for kexec_file_load system call.
*
* Copyright IBM Corp. 2018
*
* Author(s): Philipp Rudo <prudo@linux.vnet.ibm.com>
*/
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <asm/setup.h>
static int kexec_file_add_elf_kernel(struct kimage *image,
struct s390_load_data *data,
char *kernel, unsigned long kernel_len)
{
struct kexec_buf buf;
const Elf_Ehdr *ehdr;
const Elf_Phdr *phdr;
int i, ret;
ehdr = (Elf_Ehdr *)kernel;
buf.image = image;
phdr = (void *)ehdr + ehdr->e_phoff;
for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
if (phdr->p_type != PT_LOAD)
continue;
buf.buffer = kernel + phdr->p_offset;
buf.bufsz = phdr->p_filesz;
buf.mem = ALIGN(phdr->p_paddr, phdr->p_align);
buf.memsz = phdr->p_memsz;
if (phdr->p_paddr == 0) {
data->kernel_buf = buf.buffer;
data->memsz += STARTUP_NORMAL_OFFSET;
buf.buffer += STARTUP_NORMAL_OFFSET;
buf.bufsz -= STARTUP_NORMAL_OFFSET;
buf.mem += STARTUP_NORMAL_OFFSET;
buf.memsz -= STARTUP_NORMAL_OFFSET;
}
if (image->type == KEXEC_TYPE_CRASH)
buf.mem += crashk_res.start;
ret = kexec_add_buffer(&buf);
if (ret)
return ret;
data->memsz += buf.memsz;
}
return 0;
}
static void *s390_elf_load(struct kimage *image,
char *kernel, unsigned long kernel_len,
char *initrd, unsigned long initrd_len,
char *cmdline, unsigned long cmdline_len)
{
struct s390_load_data data = {0};
const Elf_Ehdr *ehdr;
const Elf_Phdr *phdr;
size_t size;
int i, ret;
/* image->fobs->probe already checked for valid ELF magic number. */
ehdr = (Elf_Ehdr *)kernel;
if (ehdr->e_type != ET_EXEC ||
ehdr->e_ident[EI_CLASS] != ELFCLASS64 ||
!elf_check_arch(ehdr))
return ERR_PTR(-EINVAL);
if (!ehdr->e_phnum || ehdr->e_phentsize != sizeof(Elf_Phdr))
return ERR_PTR(-EINVAL);
size = ehdr->e_ehsize + ehdr->e_phoff;
size += ehdr->e_phentsize * ehdr->e_phnum;
if (size > kernel_len)
return ERR_PTR(-EINVAL);
phdr = (void *)ehdr + ehdr->e_phoff;
size = ALIGN(size, phdr->p_align);
for (i = 0; i < ehdr->e_phnum; i++, phdr++) {
if (phdr->p_type == PT_INTERP)
return ERR_PTR(-EINVAL);
if (phdr->p_offset > kernel_len)
return ERR_PTR(-EINVAL);
size += ALIGN(phdr->p_filesz, phdr->p_align);
}
if (size > kernel_len)
return ERR_PTR(-EINVAL);
ret = kexec_file_add_elf_kernel(image, &data, kernel, kernel_len);
if (ret)
return ERR_PTR(ret);
if (!data.memsz)
return ERR_PTR(-EINVAL);
if (initrd) {
ret = kexec_file_add_initrd(image, &data, initrd, initrd_len);
if (ret)
return ERR_PTR(ret);
}
ret = kexec_file_add_purgatory(image, &data);
if (ret)
return ERR_PTR(ret);
return kexec_file_update_kernel(image, &data);
}
static int s390_elf_probe(const char *buf, unsigned long len)
{
const Elf_Ehdr *ehdr;
if (len < sizeof(Elf_Ehdr))
return -ENOEXEC;
ehdr = (Elf_Ehdr *)buf;
/* Only check the ELF magic number here and do proper validity check
* in the loader. Any check here that fails would send the erroneous
* ELF file to the image loader that does not care what it gets.
* (Most likely) causing behavior not intended by the user.
*/
if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
return -ENOEXEC;
return 0;
}
const struct kexec_file_ops s390_kexec_elf_ops = {
.probe = s390_elf_probe,
.load = s390_elf_load,
};
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