diff options
Diffstat (limited to 'arch/s390/kernel/kexec_elf.c')
| -rw-r--r-- | arch/s390/kernel/kexec_elf.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/arch/s390/kernel/kexec_elf.c b/arch/s390/kernel/kexec_elf.c new file mode 100644 index 000000000..5cf340b77 --- /dev/null +++ b/arch/s390/kernel/kexec_elf.c @@ -0,0 +1,152 @@ +// 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; + Elf_Addr entry; + int i, ret; + + ehdr = (Elf_Ehdr *)kernel; + buf.image = image; + if (image->type == KEXEC_TYPE_CRASH) + entry = STARTUP_KDUMP_OFFSET; + else + entry = ehdr->e_entry; + + 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 (entry - phdr->p_paddr < phdr->p_memsz) { + 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 = ALIGN(data->memsz, phdr->p_align) + 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, +}; |