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module: Move version support into a separate file
No functional change. This patch migrates module version support out of core code into kernel/module/version.c. In addition simple code refactoring to make this possible. Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,110 @@ | ||
| // SPDX-License-Identifier: GPL-2.0-or-later | ||
| /* | ||
| * Module version support | ||
| * | ||
| * Copyright (C) 2008 Rusty Russell | ||
| */ | ||
|
|
||
| #include <linux/module.h> | ||
| #include <linux/string.h> | ||
| #include <linux/printk.h> | ||
| #include "internal.h" | ||
|
|
||
| /* | ||
| * Generate the signature for all relevant module structures here. | ||
| * If these change, we don't want to try to parse the module. | ||
| */ | ||
| void module_layout(struct module *mod, | ||
| struct modversion_info *ver, | ||
| struct kernel_param *kp, | ||
| struct kernel_symbol *ks, | ||
| struct tracepoint * const *tp) | ||
| { | ||
| } | ||
| EXPORT_SYMBOL(module_layout); | ||
|
|
||
| static u32 resolve_rel_crc(const s32 *crc) | ||
| { | ||
| return *(u32 *)((void *)crc + *crc); | ||
| } | ||
|
|
||
| int check_version(const struct load_info *info, | ||
| const char *symname, | ||
| struct module *mod, | ||
| const s32 *crc) | ||
| { | ||
| Elf_Shdr *sechdrs = info->sechdrs; | ||
| unsigned int versindex = info->index.vers; | ||
| unsigned int i, num_versions; | ||
| struct modversion_info *versions; | ||
|
|
||
| /* Exporting module didn't supply crcs? OK, we're already tainted. */ | ||
| if (!crc) | ||
| return 1; | ||
|
|
||
| /* No versions at all? modprobe --force does this. */ | ||
| if (versindex == 0) | ||
| return try_to_force_load(mod, symname) == 0; | ||
|
|
||
| versions = (void *) sechdrs[versindex].sh_addr; | ||
| num_versions = sechdrs[versindex].sh_size | ||
| / sizeof(struct modversion_info); | ||
|
|
||
| for (i = 0; i < num_versions; i++) { | ||
| u32 crcval; | ||
|
|
||
| if (strcmp(versions[i].name, symname) != 0) | ||
| continue; | ||
|
|
||
| if (IS_ENABLED(CONFIG_MODULE_REL_CRCS)) | ||
| crcval = resolve_rel_crc(crc); | ||
| else | ||
| crcval = *crc; | ||
| if (versions[i].crc == crcval) | ||
| return 1; | ||
| pr_debug("Found checksum %X vs module %lX\n", | ||
| crcval, versions[i].crc); | ||
| goto bad_version; | ||
| } | ||
|
|
||
| /* Broken toolchain. Warn once, then let it go.. */ | ||
| pr_warn_once("%s: no symbol version for %s\n", info->name, symname); | ||
| return 1; | ||
|
|
||
| bad_version: | ||
| pr_warn("%s: disagrees about version of symbol %s\n", | ||
| info->name, symname); | ||
| return 0; | ||
| } | ||
|
|
||
| inline int check_modstruct_version(const struct load_info *info, | ||
| struct module *mod) | ||
| { | ||
| struct find_symbol_arg fsa = { | ||
| .name = "module_layout", | ||
| .gplok = true, | ||
| }; | ||
|
|
||
| /* | ||
| * Since this should be found in kernel (which can't be removed), no | ||
| * locking is necessary -- use preempt_disable() to placate lockdep. | ||
| */ | ||
| preempt_disable(); | ||
| if (!find_symbol(&fsa)) { | ||
| preempt_enable(); | ||
| BUG(); | ||
| } | ||
| preempt_enable(); | ||
| return check_version(info, "module_layout", mod, fsa.crc); | ||
| } | ||
|
|
||
| /* First part is kernel version, which we ignore if module has crcs. */ | ||
| inline int same_magic(const char *amagic, const char *bmagic, | ||
| bool has_crcs) | ||
| { | ||
| if (has_crcs) { | ||
| amagic += strcspn(amagic, " "); | ||
| bmagic += strcspn(bmagic, " "); | ||
| } | ||
| return strcmp(amagic, bmagic) == 0; | ||
| } |