1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Module version support |
4 | * |
5 | * Copyright (C) 2008 Rusty Russell |
6 | */ |
7 | |
8 | #include <linux/module.h> |
9 | #include <linux/string.h> |
10 | #include <linux/printk.h> |
11 | #include "internal.h" |
12 | |
13 | int check_version(const struct load_info *info, |
14 | const char *symname, |
15 | struct module *mod, |
16 | const s32 *crc) |
17 | { |
18 | Elf_Shdr *sechdrs = info->sechdrs; |
19 | unsigned int versindex = info->index.vers; |
20 | unsigned int i, num_versions; |
21 | struct modversion_info *versions; |
22 | |
23 | /* Exporting module didn't supply crcs? OK, we're already tainted. */ |
24 | if (!crc) |
25 | return 1; |
26 | |
27 | /* No versions at all? modprobe --force does this. */ |
28 | if (versindex == 0) |
29 | return try_to_force_load(mod, reason: symname) == 0; |
30 | |
31 | versions = (void *)sechdrs[versindex].sh_addr; |
32 | num_versions = sechdrs[versindex].sh_size |
33 | / sizeof(struct modversion_info); |
34 | |
35 | for (i = 0; i < num_versions; i++) { |
36 | u32 crcval; |
37 | |
38 | if (strcmp(versions[i].name, symname) != 0) |
39 | continue; |
40 | |
41 | crcval = *crc; |
42 | if (versions[i].crc == crcval) |
43 | return 1; |
44 | pr_debug("Found checksum %X vs module %lX\n" , |
45 | crcval, versions[i].crc); |
46 | goto bad_version; |
47 | } |
48 | |
49 | /* Broken toolchain. Warn once, then let it go.. */ |
50 | pr_warn_once("%s: no symbol version for %s\n" , info->name, symname); |
51 | return 1; |
52 | |
53 | bad_version: |
54 | pr_warn("%s: disagrees about version of symbol %s\n" , info->name, symname); |
55 | return 0; |
56 | } |
57 | |
58 | int check_modstruct_version(const struct load_info *info, |
59 | struct module *mod) |
60 | { |
61 | struct find_symbol_arg fsa = { |
62 | .name = "module_layout" , |
63 | .gplok = true, |
64 | }; |
65 | |
66 | /* |
67 | * Since this should be found in kernel (which can't be removed), no |
68 | * locking is necessary -- use preempt_disable() to placate lockdep. |
69 | */ |
70 | preempt_disable(); |
71 | if (!find_symbol(fsa: &fsa)) { |
72 | preempt_enable(); |
73 | BUG(); |
74 | } |
75 | preempt_enable(); |
76 | return check_version(info, symname: "module_layout" , mod, crc: fsa.crc); |
77 | } |
78 | |
79 | /* First part is kernel version, which we ignore if module has crcs. */ |
80 | int same_magic(const char *amagic, const char *bmagic, |
81 | bool has_crcs) |
82 | { |
83 | if (has_crcs) { |
84 | amagic += strcspn(amagic, " " ); |
85 | bmagic += strcspn(bmagic, " " ); |
86 | } |
87 | return strcmp(amagic, bmagic) == 0; |
88 | } |
89 | |
90 | /* |
91 | * Generate the signature for all relevant module structures here. |
92 | * If these change, we don't want to try to parse the module. |
93 | */ |
94 | void module_layout(struct module *mod, |
95 | struct modversion_info *ver, |
96 | struct kernel_param *kp, |
97 | struct kernel_symbol *ks, |
98 | struct tracepoint * const *tp) |
99 | { |
100 | } |
101 | EXPORT_SYMBOL(module_layout); |
102 | |