projects/linux·blob uaccess-cleanups · refs

146 lines · 3.6 KiB

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
13int check_version(const struct load_info *info,
14 const char *symname,
15 struct module *mod,
16 const u32 *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 struct modversion_info_ext version_ext;
23
24 /* Exporting module didn't supply crcs? OK, we're already tainted. */
25 if (!crc)
26 return 1;
27
28 /* If we have extended version info, rely on it */
29 if (info->index.vers_ext_crc) {
30 for_each_modversion_info_ext(version_ext, info) {
31 if (strcmp(version_ext.name, symname) != 0)
32 continue;
33 if (*version_ext.crc == *crc)
34 return 1;
35 pr_debug("Found checksum %X vs module %X\n",
36 *crc, *version_ext.crc);
37 goto bad_version;
38 }
39 pr_warn_once("%s: no extended symbol version for %s\n",
40 info->name, symname);
41 return 1;
42 }
43
44 /* No versions at all? modprobe --force does this. */
45 if (versindex == 0)
46 return try_to_force_load(mod, symname) == 0;
47
48 versions = (void *)sechdrs[versindex].sh_addr;
49 num_versions = sechdrs[versindex].sh_size
50 / sizeof(struct modversion_info);
51
52 for (i = 0; i < num_versions; i++) {
53 u32 crcval;
54
55 if (strcmp(versions[i].name, symname) != 0)
56 continue;
57
58 crcval = *crc;
59 if (versions[i].crc == crcval)
60 return 1;
61 pr_debug("Found checksum %X vs module %lX\n",
62 crcval, versions[i].crc);
63 goto bad_version;
64 }
65
66 /* Broken toolchain. Warn once, then let it go.. */
67 pr_warn_once("%s: no symbol version for %s\n", info->name, symname);
68 return 1;
69
70bad_version:
71 pr_warn("%s: disagrees about version of symbol %s\n", info->name, symname);
72 return 0;
73}
74
75int check_modstruct_version(const struct load_info *info,
76 struct module *mod)
77{
78 struct find_symbol_arg fsa = {
79 .name = "module_layout",
80 .gplok = true,
81 };
82 bool have_symbol;
83
84 /*
85 * Since this should be found in kernel (which can't be removed), no
86 * locking is necessary. Regardless use a RCU read section to keep
87 * lockdep happy.
88 */
89 scoped_guard(rcu)
90 have_symbol = find_symbol(&fsa);
91 BUG_ON(!have_symbol);
92
93 return check_version(info, "module_layout", mod, fsa.crc);
94}
95
96/* First part is kernel version, which we ignore if module has crcs. */
97int same_magic(const char *amagic, const char *bmagic,
98 bool has_crcs)
99{
100 if (has_crcs) {
101 amagic += strcspn(amagic, " ");
102 bmagic += strcspn(bmagic, " ");
103 }
104 return strcmp(amagic, bmagic) == 0;
105}
106
107void modversion_ext_start(const struct load_info *info,
108 struct modversion_info_ext *start)
109{
110 unsigned int crc_idx = info->index.vers_ext_crc;
111 unsigned int name_idx = info->index.vers_ext_name;
112 Elf_Shdr *sechdrs = info->sechdrs;
113
114 /*
115 * Both of these fields are needed for this to be useful
116 * Any future fields should be initialized to NULL if absent.
117 */
118 if (crc_idx == 0 || name_idx == 0) {
119 start->remaining = 0;
120 return;
121 }
122
123 start->crc = (const u32 *)sechdrs[crc_idx].sh_addr;
124 start->name = (const char *)sechdrs[name_idx].sh_addr;
125 start->remaining = sechdrs[crc_idx].sh_size / sizeof(*start->crc);
126}
127
128void modversion_ext_advance(struct modversion_info_ext *vers)
129{
130 vers->remaining--;
131 vers->crc++;
132 vers->name += strlen(vers->name) + 1;
133}
134
135/*
136 * Generate the signature for all relevant module structures here.
137 * If these change, we don't want to try to parse the module.
138 */
139void module_layout(struct module *mod,
140 struct modversion_info *ver,
141 struct kernel_param *kp,
142 struct kernel_symbol *ks,
143 struct tracepoint * const *tp)
144{
145}
146EXPORT_SYMBOL(module_layout);