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[82.17.115.212]) by smtp.gmail.com with ESMTPSA id n15sm28281489wri.80.2022.02.22.06.13.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Feb 2022 06:13:20 -0800 (PST) From: Aaron Tomlin To: mcgrof@kernel.org, christophe.leroy@csgroup.eu Cc: cl@linux.com, pmladek@suse.com, mbenes@suse.cz, akpm@linux-foundation.org, jeyu@kernel.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, void@manifault.com, atomlin@atomlin.com, allen.lkml@gmail.com, joe@perches.com, msuchanek@suse.de, oleksandr@natalenko.name Subject: [PATCH v8 13/13] module: Move version support into a separate file Date: Tue, 22 Feb 2022 14:13:03 +0000 Message-Id: <20220222141303.1392190-14-atomlin@redhat.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220222141303.1392190-1-atomlin@redhat.com> References: <20220222141303.1392190-1-atomlin@redhat.com> MIME-Version: 1.0 Precedence: bulk List-ID: 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 Reviewed-by: Christophe Leroy --- kernel/module/Makefile | 1 + kernel/module/internal.h | 48 ++++++++++++ kernel/module/main.c | 156 ++------------------------------------- kernel/module/version.c | 109 +++++++++++++++++++++++++++ 4 files changed, 166 insertions(+), 148 deletions(-) create mode 100644 kernel/module/version.c diff --git a/kernel/module/Makefile b/kernel/module/Makefile index cf8dcdc6b55f..a46e6361017f 100644 --- a/kernel/module/Makefile +++ b/kernel/module/Makefile @@ -17,3 +17,4 @@ obj-$(CONFIG_DEBUG_KMEMLEAK) += debug_kmemleak.o obj-$(CONFIG_KALLSYMS) += kallsyms.o obj-$(CONFIG_PROC_FS) += procfs.o obj-$(CONFIG_SYSFS) += sysfs.o +obj-$(CONFIG_MODVERSIONS) += version.o diff --git a/kernel/module/internal.h b/kernel/module/internal.h index 62d749ef695e..3fc139d5074b 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -70,7 +70,27 @@ struct load_info { } index; }; +enum mod_license { + NOT_GPL_ONLY, + GPL_ONLY, +}; + +struct find_symbol_arg { + /* Input */ + const char *name; + bool gplok; + bool warn; + + /* Output */ + struct module *owner; + const s32 *crc; + const struct kernel_symbol *sym; + enum mod_license license; +}; + int mod_verify_sig(const void *mod, struct load_info *info); +int try_to_force_load(struct module *mod, const char *reason); +bool find_symbol(struct find_symbol_arg *fsa); struct module *find_module_all(const char *name, size_t len, bool even_unformed); int cmp_name(const void *name, const void *sym); long module_get_offset(struct module *mod, unsigned int *size, Elf_Shdr *sechdr, @@ -225,3 +245,31 @@ static inline int mod_sysfs_setup(struct module *mod, static inline void mod_sysfs_teardown(struct module *mod) { } static inline void init_param_lock(struct module *mod) { } #endif /* CONFIG_SYSFS */ + +#ifdef CONFIG_MODVERSIONS +int check_version(const struct load_info *info, + const char *symname, struct module *mod, const s32 *crc); +void module_layout(struct module *mod, struct modversion_info *ver, struct kernel_param *kp, + struct kernel_symbol *ks, struct tracepoint * const *tp); +int check_modstruct_version(const struct load_info *info, struct module *mod); +int same_magic(const char *amagic, const char *bmagic, bool has_crcs); +#else /* !CONFIG_MODVERSIONS */ +static inline int check_version(const struct load_info *info, + const char *symname, + struct module *mod, + const s32 *crc) +{ + return 1; +} + +static inline int check_modstruct_version(const struct load_info *info, + struct module *mod) +{ + return 1; +} + +static inline int same_magic(const char *amagic, const char *bmagic, bool has_crcs) +{ + return strcmp(amagic, bmagic) == 0; +} +#endif /* CONFIG_MODVERSIONS */ diff --git a/kernel/module/main.c b/kernel/module/main.c index bcc4f7a82649..0749afdc34b5 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -86,6 +86,12 @@ struct mod_tree_root mod_tree __cacheline_aligned = { static unsigned long module_addr_min = -1UL, module_addr_max; #endif /* CONFIG_MODULES_TREE_LOOKUP */ +struct symsearch { + const struct kernel_symbol *start, *stop; + const s32 *crcs; + enum mod_license license; +}; + /* * Bounds of module text, for speeding up __module_address. * Protected by module_mutex. @@ -244,28 +250,6 @@ static __maybe_unused void *any_section_objs(const struct load_info *info, #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL) #endif -struct symsearch { - const struct kernel_symbol *start, *stop; - const s32 *crcs; - enum mod_license { - NOT_GPL_ONLY, - GPL_ONLY, - } license; -}; - -struct find_symbol_arg { - /* Input */ - const char *name; - bool gplok; - bool warn; - - /* Output */ - struct module *owner; - const s32 *crc; - const struct kernel_symbol *sym; - enum mod_license license; -}; - static bool check_exported_symbol(const struct symsearch *syms, struct module *owner, unsigned int symnum, void *data) @@ -327,7 +311,7 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms, * Find an exported symbol and return it, along with, (optional) crc and * (optional) module which owns it. Needs preempt disabled or module_mutex. */ -static bool find_symbol(struct find_symbol_arg *fsa) +bool find_symbol(struct find_symbol_arg *fsa) { static const struct symsearch arr[] = { { __start___ksymtab, __stop___ksymtab, __start___kcrctab, @@ -1001,7 +985,7 @@ size_t modinfo_attrs_count = ARRAY_SIZE(modinfo_attrs); static const char vermagic[] = VERMAGIC_STRING; -static int try_to_force_load(struct module *mod, const char *reason) +int try_to_force_load(struct module *mod, const char *reason) { #ifdef CONFIG_MODULE_FORCE_LOAD if (!test_taint(TAINT_FORCED_MODULE)) @@ -1013,115 +997,6 @@ static int try_to_force_load(struct module *mod, const char *reason) #endif } -#ifdef CONFIG_MODVERSIONS - -static u32 resolve_rel_crc(const s32 *crc) -{ - return *(u32 *)((void *)crc + *crc); -} - -static 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; -} - -static 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. */ -static 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; -} -#else -static inline int check_version(const struct load_info *info, - const char *symname, - struct module *mod, - const s32 *crc) -{ - return 1; -} - -static inline int check_modstruct_version(const struct load_info *info, - struct module *mod) -{ - return 1; -} - -static inline int same_magic(const char *amagic, const char *bmagic, - bool has_crcs) -{ - return strcmp(amagic, bmagic) == 0; -} -#endif /* CONFIG_MODVERSIONS */ - static char *get_modinfo(const struct load_info *info, const char *tag); static char *get_next_modinfo(const struct load_info *info, const char *tag, char *prev); @@ -3247,18 +3122,3 @@ void print_modules(void) pr_cont(" [last unloaded: %s]", last_unloaded_module); pr_cont("\n"); } - -#ifdef CONFIG_MODVERSIONS -/* - * 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); -#endif diff --git a/kernel/module/version.c b/kernel/module/version.c new file mode 100644 index 000000000000..adaedce1dc97 --- /dev/null +++ b/kernel/module/version.c @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Module version support + * + * Copyright (C) 2008 Rusty Russell + */ + +#include +#include +#include +#include "internal.h" + +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; +} + +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. */ +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; +} + +/* + * 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);