| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
|---|
| 2 | /* |
|---|
| 3 | * Module livepatch support |
|---|
| 4 | * |
|---|
| 5 | * Copyright (C) 2016 Jessica Yu <jeyu@redhat.com> |
|---|
| 6 | */ |
|---|
| 7 | |
|---|
| 8 | #include <linux/module.h> |
|---|
| 9 | #include <linux/string.h> |
|---|
| 10 | #include <linux/slab.h> |
|---|
| 11 | #include "internal.h" |
|---|
| 12 | |
|---|
| 13 | /* |
|---|
| 14 | * Persist ELF information about a module. Copy the ELF header, |
|---|
| 15 | * section header table, section string table, and symtab section |
|---|
| 16 | * index from info to mod->klp_info. |
|---|
| 17 | */ |
|---|
| 18 | int copy_module_elf(struct module *mod, struct load_info *info) |
|---|
| 19 | { |
|---|
| 20 | unsigned int size, symndx; |
|---|
| 21 | int ret; |
|---|
| 22 | |
|---|
| 23 | size = sizeof(*mod->klp_info); |
|---|
| 24 | mod->klp_info = kmalloc(size, GFP_KERNEL); |
|---|
| 25 | if (!mod->klp_info) |
|---|
| 26 | return -ENOMEM; |
|---|
| 27 | |
|---|
| 28 | /* ELF header */ |
|---|
| 29 | size = sizeof(mod->klp_info->hdr); |
|---|
| 30 | memcpy(&mod->klp_info->hdr, info->hdr, size); |
|---|
| 31 | |
|---|
| 32 | /* ELF section header table */ |
|---|
| 33 | size = sizeof(*info->sechdrs) * info->hdr->e_shnum; |
|---|
| 34 | mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL); |
|---|
| 35 | if (!mod->klp_info->sechdrs) { |
|---|
| 36 | ret = -ENOMEM; |
|---|
| 37 | goto free_info; |
|---|
| 38 | } |
|---|
| 39 | |
|---|
| 40 | /* ELF section name string table */ |
|---|
| 41 | size = info->sechdrs[info->hdr->e_shstrndx].sh_size; |
|---|
| 42 | mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL); |
|---|
| 43 | if (!mod->klp_info->secstrings) { |
|---|
| 44 | ret = -ENOMEM; |
|---|
| 45 | goto free_sechdrs; |
|---|
| 46 | } |
|---|
| 47 | |
|---|
| 48 | /* ELF symbol section index */ |
|---|
| 49 | symndx = info->index.sym; |
|---|
| 50 | mod->klp_info->symndx = symndx; |
|---|
| 51 | |
|---|
| 52 | /* |
|---|
| 53 | * For livepatch modules, core_kallsyms.symtab is a complete |
|---|
| 54 | * copy of the original symbol table. Adjust sh_addr to point |
|---|
| 55 | * to core_kallsyms.symtab since the copy of the symtab in module |
|---|
| 56 | * init memory is freed at the end of do_init_module(). |
|---|
| 57 | */ |
|---|
| 58 | mod->klp_info->sechdrs[symndx].sh_addr = (unsigned long)mod->core_kallsyms.symtab; |
|---|
| 59 | |
|---|
| 60 | return 0; |
|---|
| 61 | |
|---|
| 62 | free_sechdrs: |
|---|
| 63 | kfree(objp: mod->klp_info->sechdrs); |
|---|
| 64 | free_info: |
|---|
| 65 | kfree(objp: mod->klp_info); |
|---|
| 66 | return ret; |
|---|
| 67 | } |
|---|
| 68 | |
|---|
| 69 | void free_module_elf(struct module *mod) |
|---|
| 70 | { |
|---|
| 71 | kfree(objp: mod->klp_info->sechdrs); |
|---|
| 72 | kfree(objp: mod->klp_info->secstrings); |
|---|
| 73 | kfree(objp: mod->klp_info); |
|---|
| 74 | } |
|---|
| 75 | |
|---|
