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(mod->klp_info->sechdrs); 64 free_info: 65 kfree(mod->klp_info); 66 return ret; 67 } 68 69 void free_module_elf(struct module *mod) 70 { 71 kfree(mod->klp_info->sechdrs); 72 kfree(mod->klp_info->secstrings); 73 kfree(mod->klp_info); 74 } 75