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47889798 AT |
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 | ||
47889798 AT |
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, 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 | ||
ef98f9cf | 41 | crcval = *crc; |
47889798 AT |
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)) { | |
72 | preempt_enable(); | |
73 | BUG(); | |
74 | } | |
75 | preempt_enable(); | |
76 | return check_version(info, "module_layout", mod, 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); |