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