// SPDX-License-Identifier: GPL-2.0-or-later /* Copyright (C) 2002 Richard Henderson Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM. */ #define INCLUDE_VERMAGIC #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "module-internal.h" #define CREATE_TRACE_POINTS #include #ifndef ARCH_SHF_SMALL #define ARCH_SHF_SMALL 0 #endif /* * Modules' sections will be aligned on page boundaries * to ensure complete separation of code and data, but * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y */ #ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX # define debug_align(X) ALIGN(X, PAGE_SIZE) #else # define debug_align(X) (X) #endif /* If this is set, the section belongs in the init part of the module */ #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1)) /* * Mutex protects: * 1) List of modules (also safely readable with preempt_disable), * 2) module_use links, * 3) module_addr_min/module_addr_max. * (delete and add uses RCU list operations). */ DEFINE_MUTEX(module_mutex); EXPORT_SYMBOL_GPL(module_mutex); static LIST_HEAD(modules); /* Work queue for freeing init sections in success case */ static struct work_struct init_free_wq; static struct llist_head init_free_list; #ifdef CONFIG_MODULES_TREE_LOOKUP /* * Use a latched RB-tree for __module_address(); this allows us to use * RCU-sched lookups of the address from any context. * * This is conditional on PERF_EVENTS || TRACING because those can really hit * __module_address() hard by doing a lot of stack unwinding; potentially from * NMI context. */ static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n) { struct module_layout *layout = container_of(n, struct module_layout, mtn.node); return (unsigned long)layout->base; } static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n) { struct module_layout *layout = container_of(n, struct module_layout, mtn.node); return (unsigned long)layout->size; } static __always_inline bool mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b) { return __mod_tree_val(a) < __mod_tree_val(b); } static __always_inline int mod_tree_comp(void *key, struct latch_tree_node *n) { unsigned long val = (unsigned long)key; unsigned long start, end; start = __mod_tree_val(n); if (val < start) return -1; end = start + __mod_tree_size(n); if (val >= end) return 1; return 0; } static const struct latch_tree_ops mod_tree_ops = { .less = mod_tree_less, .comp = mod_tree_comp, }; static struct mod_tree_root { struct latch_tree_root root; unsigned long addr_min; unsigned long addr_max; } mod_tree __cacheline_aligned = { .addr_min = -1UL, }; #define module_addr_min mod_tree.addr_min #define module_addr_max mod_tree.addr_max static noinline void __mod_tree_insert(struct mod_tree_node *node) { latch_tree_insert(&node->node, &mod_tree.root, &mod_tree_ops); } static void __mod_tree_remove(struct mod_tree_node *node) { latch_tree_erase(&node->node, &mod_tree.root, &mod_tree_ops); } /* * These modifications: insert, remove_init and remove; are serialized by the * module_mutex. */ static void mod_tree_insert(struct module *mod) { mod->core_layout.mtn.mod = mod; mod->init_layout.mtn.mod = mod; __mod_tree_insert(&mod->core_layout.mtn); if (mod->init_layout.size) __mod_tree_insert(&mod->init_layout.mtn); } static void mod_tree_remove_init(struct module *mod) { if (mod->init_layout.size) __mod_tree_remove(&mod->init_layout.mtn); } static void mod_tree_remove(struct module *mod) { __mod_tree_remove(&mod->core_layout.mtn); mod_tree_remove_init(mod); } static struct module *mod_find(unsigned long addr) { struct latch_tree_node *ltn; ltn = latch_tree_find((void *)addr, &mod_tree.root, &mod_tree_ops); if (!ltn) return NULL; return container_of(ltn, struct mod_tree_node, node)->mod; } #else /* MODULES_TREE_LOOKUP */ static unsigned long module_addr_min = -1UL, module_addr_max = 0; static void mod_tree_insert(struct module *mod) { } static void mod_tree_remove_init(struct module *mod) { } static void mod_tree_remove(struct module *mod) { } static struct module *mod_find(unsigned long addr) { struct module *mod; list_for_each_entry_rcu(mod, &modules, list, lockdep_is_held(&module_mutex)) { if (within_module(addr, mod)) return mod; } return NULL; } #endif /* MODULES_TREE_LOOKUP */ /* * Bounds of module text, for speeding up __module_address. * Protected by module_mutex. */ static void __mod_update_bounds(void *base, unsigned int size) { unsigned long min = (unsigned long)base; unsigned long max = min + size; if (min < module_addr_min) module_addr_min = min; if (max > module_addr_max) module_addr_max = max; } static void mod_update_bounds(struct module *mod) { __mod_update_bounds(mod->core_layout.base, mod->core_layout.size); if (mod->init_layout.size) __mod_update_bounds(mod->init_layout.base, mod->init_layout.size); } #ifdef CONFIG_KGDB_KDB struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */ #endif /* CONFIG_KGDB_KDB */ static void module_assert_mutex(void) { lockdep_assert_held(&module_mutex); } static void module_assert_mutex_or_preempt(void) { #ifdef CONFIG_LOCKDEP if (unlikely(!debug_locks)) return; WARN_ON_ONCE(!rcu_read_lock_sched_held() && !lockdep_is_held(&module_mutex)); #endif } static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE); module_param(sig_enforce, bool_enable_only, 0644); /* * Export sig_enforce kernel cmdline parameter to allow other subsystems rely * on that instead of directly to CONFIG_MODULE_SIG_FORCE config. */ bool is_module_sig_enforced(void) { return sig_enforce; } EXPORT_SYMBOL(is_module_sig_enforced); void set_module_sig_enforced(void) { sig_enforce = true; } /* Block module loading/unloading? */ int modules_disabled = 0; core_param(nomodule, modules_disabled, bint, 0); /* Waiting for a module to finish initializing? */ static DECLARE_WAIT_QUEUE_HEAD(module_wq); static BLOCKING_NOTIFIER_HEAD(module_notify_list); int register_module_notifier(struct notifier_block *nb) { return blocking_notifier_chain_register(&module_notify_list, nb); } EXPORT_SYMBOL(register_module_notifier); int unregister_module_notifier(struct notifier_block *nb) { return blocking_notifier_chain_unregister(&module_notify_list, nb); } EXPORT_SYMBOL(unregister_module_notifier); /* * We require a truly strong try_module_get(): 0 means success. * Otherwise an error is returned due to ongoing or failed * initialization etc. */ static inline int strong_try_module_get(struct module *mod) { BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED); if (mod && mod->state == MODULE_STATE_COMING) return -EBUSY; if (try_module_get(mod)) return 0; else return -ENOENT; } static inline void add_taint_module(struct module *mod, unsigned flag, enum lockdep_ok lockdep_ok) { add_taint(flag, lockdep_ok); set_bit(flag, &mod->taints); } /* * A thread that wants to hold a reference to a module only while it * is running can call this to safely exit. nfsd and lockd use this. */ void __noreturn __module_put_and_exit(struct module *mod, long code) { module_put(mod); do_exit(code); } EXPORT_SYMBOL(__module_put_and_exit); /* Find a module section: 0 means not found. */ static unsigned int find_sec(const struct load_info *info, const char *name) { unsigned int i; for (i = 1; i < info->hdr->e_shnum; i++) { Elf_Shdr *shdr = &info->sechdrs[i]; /* Alloc bit cleared means "ignore it." */ if ((shdr->sh_flags & SHF_ALLOC) && strcmp(info->secstrings + shdr->sh_name, name) == 0) return i; } return 0; } /* Find a module section, or NULL. */ static void *section_addr(const struct load_info *info, const char *name) { /* Section 0 has sh_addr 0. */ return (void *)info->sechdrs[find_sec(info, name)].sh_addr; } /* Find a module section, or NULL. Fill in number of "objects" in section. */ static void *section_objs(const struct load_info *info, const char *name, size_t object_size, unsigned int *num) { unsigned int sec = find_sec(info, name); /* Section 0 has sh_addr 0 and sh_size 0. */ *num = info->sechdrs[sec].sh_size / object_size; return (void *)info->sechdrs[sec].sh_addr; } /* Provided by the linker */ extern const struct kernel_symbol __start___ksymtab[]; extern const struct kernel_symbol __stop___ksymtab[]; extern const struct kernel_symbol __start___ksymtab_gpl[]; extern const struct kernel_symbol __stop___ksymtab_gpl[]; extern const struct kernel_symbol __start___ksymtab_gpl_future[]; extern const struct kernel_symbol __stop___ksymtab_gpl_future[]; extern const s32 __start___kcrctab[]; extern const s32 __start___kcrctab_gpl[]; extern const s32 __start___kcrctab_gpl_future[]; #ifdef CONFIG_UNUSED_SYMBOLS extern const struct kernel_symbol __start___ksymtab_unused[]; extern const struct kernel_symbol __stop___ksymtab_unused[]; extern const struct kernel_symbol __start___ksymtab_unused_gpl[]; extern const struct kernel_symbol __stop___ksymtab_unused_gpl[]; extern const s32 __start___kcrctab_unused[]; extern const s32 __start___kcrctab_unused_gpl[]; #endif #ifndef CONFIG_MODVERSIONS #define symversion(base, idx) NULL #else #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL) #endif static bool each_symbol_in_section(const struct symsearch *arr, unsigned int arrsize, struct module *owner, bool (*fn)(const struct symsearch *syms, struct module *owner, void *data), void *data) { unsigned int j; for (j = 0; j < arrsize; j++) { if (fn(&arr[j], owner, data)) return true; } return false; } /* Returns true as soon as fn returns true, otherwise false. */ static bool each_symbol_section(bool (*fn)(const struct symsearch *arr, struct module *owner, void *data), void *data) { struct module *mod; static const struct symsearch arr[] = { { __start___ksymtab, __stop___ksymtab, __start___kcrctab, NOT_GPL_ONLY, false }, { __start___ksymtab_gpl, __stop___ksymtab_gpl, __start___kcrctab_gpl, GPL_ONLY, false }, { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future, __start___kcrctab_gpl_future, WILL_BE_GPL_ONLY, false }, #ifdef CONFIG_UNUSED_SYMBOLS { __start___ksymtab_unused, __stop___ksymtab_unused, __start___kcrctab_unused, NOT_GPL_ONLY, true }, { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl, __start___kcrctab_unused_gpl, GPL_ONLY, true }, #endif }; module_assert_mutex_or_preempt(); if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data)) return true; list_for_each_entry_rcu(mod, &modules, list, lockdep_is_held(&module_mutex)) { struct symsearch arr[] = { { mod->syms, mod->syms + mod->num_syms, mod->crcs, NOT_GPL_ONLY, false }, { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms, mod->gpl_crcs, GPL_ONLY, false }, { mod->gpl_future_syms, mod->gpl_future_syms + mod->num_gpl_future_syms, mod->gpl_future_crcs, WILL_BE_GPL_ONLY, false }, #ifdef CONFIG_UNUSED_SYMBOLS { mod->unused_syms, mod->unused_syms + mod->num_unused_syms, mod->unused_crcs, NOT_GPL_ONLY, true }, { mod->unused_gpl_syms, mod->unused_gpl_syms + mod->num_unused_gpl_syms, mod->unused_gpl_crcs, GPL_ONLY, true }, #endif }; if (mod->state == MODULE_STATE_UNFORMED) continue; if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data)) return true; } return false; } 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) { struct find_symbol_arg *fsa = data; if (!fsa->gplok) { if (syms->license == GPL_ONLY) return false; if (syms->license == WILL_BE_GPL_ONLY && fsa->warn) { pr_warn("Symbol %s is being used by a non-GPL module, " "which will not be allowed in the future\n", fsa->name); } } #ifdef CONFIG_UNUSED_SYMBOLS if (syms->unused && fsa->warn) { pr_warn("Symbol %s is marked as UNUSED, however this module is " "using it.\n", fsa->name); pr_warn("This symbol will go away in the future.\n"); pr_warn("Please evaluate if this is the right api to use and " "if it really is, submit a report to the linux kernel " "mailing list together with submitting your code for " "inclusion.\n"); } #endif fsa->owner = owner; fsa->crc = symversion(syms->crcs, symnum); fsa->sym = &syms->start[symnum]; fsa->license = syms->license; return true; } static unsigned long kernel_symbol_value(const struct kernel_symbol *sym) { #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS return (unsigned long)offset_to_ptr(&sym->value_offset); #else return sym->value; #endif } static const char *kernel_symbol_name(const struct kernel_symbol *sym) { #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS return offset_to_ptr(&sym->name_offset); #else return sym->name; #endif } static const char *kernel_symbol_namespace(const struct kernel_symbol *sym) { #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS if (!sym->namespace_offset) return NULL; return offset_to_ptr(&sym->namespace_offset); #else return sym->namespace; #endif } static int cmp_name(const void *name, const void *sym) { return strcmp(name, kernel_symbol_name(sym)); } static bool find_exported_symbol_in_section(const struct symsearch *syms, struct module *owner, void *data) { struct find_symbol_arg *fsa = data; struct kernel_symbol *sym; sym = bsearch(fsa->name, syms->start, syms->stop - syms->start, sizeof(struct kernel_symbol), cmp_name); if (sym != NULL && check_exported_symbol(syms, owner, sym - syms->start, data)) return true; return false; } /* Find an exported symbol and return it, along with, (optional) crc and * (optional) module which owns it. Needs preempt disabled or module_mutex. */ static const struct kernel_symbol *find_symbol(const char *name, struct module **owner, const s32 **crc, enum mod_license *license, bool gplok, bool warn) { struct find_symbol_arg fsa; fsa.name = name; fsa.gplok = gplok; fsa.warn = warn; if (each_symbol_section(find_exported_symbol_in_section, &fsa)) { if (owner) *owner = fsa.owner; if (crc) *crc = fsa.crc; if (license) *license = fsa.license; return fsa.sym; } pr_debug("Failed to find symbol %s\n", name); return NULL; } /* * Search for module by name: must hold module_mutex (or preempt disabled * for read-only access). */ static struct module *find_module_all(const char *name, size_t len, bool even_unformed) { struct module *mod; module_assert_mutex_or_preempt(); list_for_each_entry_rcu(mod, &modules, list, lockdep_is_held(&module_mutex)) { if (!even_unformed && mod->state == MODULE_STATE_UNFORMED) continue; if (strlen(mod->name) == len && !memcmp(mod->name, name, len)) return mod; } return NULL; } struct module *find_module(const char *name) { module_assert_mutex(); return find_module_all(name, strlen(name), false); } EXPORT_SYMBOL_GPL(find_module); #ifdef CONFIG_SMP static inline void __percpu *mod_percpu(struct module *mod) { return mod->percpu; } static int percpu_modalloc(struct module *mod, struct load_info *info) { Elf_Shdr *pcpusec = &info->sechdrs[info->index.pcpu]; unsigned long align = pcpusec->sh_addralign; if (!pcpusec->sh_size) return 0; if (align > PAGE_SIZE) { pr_warn("%s: per-cpu alignment %li > %li\n", mod->name, align, PAGE_SIZE); align = PAGE_SIZE; } mod->percpu = __alloc_reserved_percpu(pcpusec->sh_size, align); if (!mod->percpu) { pr_warn("%s: Could not allocate %lu bytes percpu data\n", mod->name, (unsigned long)pcpusec->sh_size); return -ENOMEM; } mod->percpu_size = pcpusec->sh_size; return 0; } static void percpu_modfree(struct module *mod) { free_percpu(mod->percpu); } static unsigned int find_pcpusec(struct load_info *info) { return find_sec(info, ".data..percpu"); } static void percpu_modcopy(struct module *mod, const void *from, unsigned long size) { int cpu; for_each_possible_cpu(cpu) memcpy(per_cpu_ptr(mod->percpu, cpu), from, size); } bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr) { struct module *mod; unsigned int cpu; preempt_disable(); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; if (!mod->percpu_size) continue; for_each_possible_cpu(cpu) { void *start = per_cpu_ptr(mod->percpu, cpu); void *va = (void *)addr; if (va >= start && va < start + mod->percpu_size) { if (can_addr) { *can_addr = (unsigned long) (va - start); *can_addr += (unsigned long) per_cpu_ptr(mod->percpu, get_boot_cpu_id()); } preempt_enable(); return true; } } } preempt_enable(); return false; } /** * is_module_percpu_address - test whether address is from module static percpu * @addr: address to test * * Test whether @addr belongs to module static percpu area. * * RETURNS: * %true if @addr is from module static percpu area */ bool is_module_percpu_address(unsigned long addr) { return __is_module_percpu_address(addr, NULL); } #else /* ... !CONFIG_SMP */ static inline void __percpu *mod_percpu(struct module *mod) { return NULL; } static int percpu_modalloc(struct module *mod, struct load_info *info) { /* UP modules shouldn't have this section: ENOMEM isn't quite right */ if (info->sechdrs[info->index.pcpu].sh_size != 0) return -ENOMEM; return 0; } static inline void percpu_modfree(struct module *mod) { } static unsigned int find_pcpusec(struct load_info *info) { return 0; } static inline void percpu_modcopy(struct module *mod, const void *from, unsigned long size) { /* pcpusec should be 0, and size of that section should be 0. */ BUG_ON(size != 0); } bool is_module_percpu_address(unsigned long addr) { return false; } bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr) { return false; } #endif /* CONFIG_SMP */ #define MODINFO_ATTR(field) \ static void setup_modinfo_##field(struct module *mod, const char *s) \ { \ mod->field = kstrdup(s, GFP_KERNEL); \ } \ static ssize_t show_modinfo_##field(struct module_attribute *mattr, \ struct module_kobject *mk, char *buffer) \ { \ return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field); \ } \ static int modinfo_##field##_exists(struct module *mod) \ { \ return mod->field != NULL; \ } \ static void free_modinfo_##field(struct module *mod) \ { \ kfree(mod->field); \ mod->field = NULL; \ } \ static struct module_attribute modinfo_##field = { \ .attr = { .name = __stringify(field), .mode = 0444 }, \ .show = show_modinfo_##field, \ .setup = setup_modinfo_##field, \ .test = modinfo_##field##_exists, \ .free = free_modinfo_##field, \ }; MODINFO_ATTR(version); MODINFO_ATTR(srcversion); static char last_unloaded_module[MODULE_NAME_LEN+1]; #ifdef CONFIG_MODULE_UNLOAD EXPORT_TRACEPOINT_SYMBOL(module_get); /* MODULE_REF_BASE is the base reference count by kmodule loader. */ #define MODULE_REF_BASE 1 /* Init the unload section of the module. */ static int module_unload_init(struct module *mod) { /* * Initialize reference counter to MODULE_REF_BASE. * refcnt == 0 means module is going. */ atomic_set(&mod->refcnt, MODULE_REF_BASE); INIT_LIST_HEAD(&mod->source_list); INIT_LIST_HEAD(&mod->target_list); /* Hold reference count during initialization. */ atomic_inc(&mod->refcnt); return 0; } /* Does a already use b? */ static int already_uses(struct module *a, struct module *b) { struct module_use *use; list_for_each_entry(use, &b->source_list, source_list) { if (use->source == a) { pr_debug("%s uses %s!\n", a->name, b->name); return 1; } } pr_debug("%s does not use %s!\n", a->name, b->name); return 0; } /* * Module a uses b * - we add 'a' as a "source", 'b' as a "target" of module use * - the module_use is added to the list of 'b' sources (so * 'b' can walk the list to see who sourced them), and of 'a' * targets (so 'a' can see what modules it targets). */ static int add_module_usage(struct module *a, struct module *b) { struct module_use *use; pr_debug("Allocating new usage for %s.\n", a->name); use = kmalloc(sizeof(*use), GFP_ATOMIC); if (!use) return -ENOMEM; use->source = a; use->target = b; list_add(&use->source_list, &b->source_list); list_add(&use->target_list, &a->target_list); return 0; } /* Module a uses b: caller needs module_mutex() */ static int ref_module(struct module *a, struct module *b) { int err; if (b == NULL || already_uses(a, b)) return 0; /* If module isn't available, we fail. */ err = strong_try_module_get(b); if (err) return err; err = add_module_usage(a, b); if (err) { module_put(b); return err; } return 0; } /* Clear the unload stuff of the module. */ static void module_unload_free(struct module *mod) { struct module_use *use, *tmp; mutex_lock(&module_mutex); list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) { struct module *i = use->target; pr_debug("%s unusing %s\n", mod->name, i->name); module_put(i); list_del(&use->source_list); list_del(&use->target_list); kfree(use); } mutex_unlock(&module_mutex); } #ifdef CONFIG_MODULE_FORCE_UNLOAD static inline int try_force_unload(unsigned int flags) { int ret = (flags & O_TRUNC); if (ret) add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE); return ret; } #else static inline int try_force_unload(unsigned int flags) { return 0; } #endif /* CONFIG_MODULE_FORCE_UNLOAD */ /* Try to release refcount of module, 0 means success. */ static int try_release_module_ref(struct module *mod) { int ret; /* Try to decrement refcnt which we set at loading */ ret = atomic_sub_return(MODULE_REF_BASE, &mod->refcnt); BUG_ON(ret < 0); if (ret) /* Someone can put this right now, recover with checking */ ret = atomic_add_unless(&mod->refcnt, MODULE_REF_BASE, 0); return ret; } static int try_stop_module(struct module *mod, int flags, int *forced) { /* If it's not unused, quit unless we're forcing. */ if (try_release_module_ref(mod) != 0) { *forced = try_force_unload(flags); if (!(*forced)) return -EWOULDBLOCK; } /* Mark it as dying. */ mod->state = MODULE_STATE_GOING; return 0; } /** * module_refcount - return the refcount or -1 if unloading * * @mod: the module we're checking * * Returns: * -1 if the module is in the process of unloading * otherwise the number of references in the kernel to the module */ int module_refcount(struct module *mod) { return atomic_read(&mod->refcnt) - MODULE_REF_BASE; } EXPORT_SYMBOL(module_refcount); /* This exists whether we can unload or not */ static void free_module(struct module *mod); SYSCALL_DEFINE2(delete_module, const char __user *, name_user, unsigned int, flags) { struct module *mod; char name[MODULE_NAME_LEN]; int ret, forced = 0; if (!capable(CAP_SYS_MODULE) || modules_disabled) return -EPERM; if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0) return -EFAULT; name[MODULE_NAME_LEN-1] = '\0'; audit_log_kern_module(name); if (mutex_lock_interruptible(&module_mutex) != 0) return -EINTR; mod = find_module(name); if (!mod) { ret = -ENOENT; goto out; } if (!list_empty(&mod->source_list)) { /* Other modules depend on us: get rid of them first. */ ret = -EWOULDBLOCK; goto out; } /* Doing init or already dying? */ if (mod->state != MODULE_STATE_LIVE) { /* FIXME: if (force), slam module count damn the torpedoes */ pr_debug("%s already dying\n", mod->name); ret = -EBUSY; goto out; } /* If it has an init func, it must have an exit func to unload */ if (mod->init && !mod->exit) { forced = try_force_unload(flags); if (!forced) { /* This module can't be removed */ ret = -EBUSY; goto out; } } /* Stop the machine so refcounts can't move and disable module. */ ret = try_stop_module(mod, flags, &forced); if (ret != 0) goto out; mutex_unlock(&module_mutex); /* Final destruction now no one is using it. */ if (mod->exit != NULL) mod->exit(); blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_GOING, mod); klp_module_going(mod); ftrace_release_mod(mod); async_synchronize_full(); /* Store the name of the last unloaded module for diagnostic purposes */ strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module)); free_module(mod); /* someone could wait for the module in add_unformed_module() */ wake_up_all(&module_wq); return 0; out: mutex_unlock(&module_mutex); return ret; } static inline void print_unload_info(struct seq_file *m, struct module *mod) { struct module_use *use; int printed_something = 0; seq_printf(m, " %i ", module_refcount(mod)); /* * Always include a trailing , so userspace can differentiate * between this and the old multi-field proc format. */ list_for_each_entry(use, &mod->source_list, source_list) { printed_something = 1; seq_printf(m, "%s,", use->source->name); } if (mod->init != NULL && mod->exit == NULL) { printed_something = 1; seq_puts(m, "[permanent],"); } if (!printed_something) seq_puts(m, "-"); } void __symbol_put(const char *symbol) { struct module *owner; preempt_disable(); if (!find_symbol(symbol, &owner, NULL, NULL, true, false)) BUG(); module_put(owner); preempt_enable(); } EXPORT_SYMBOL(__symbol_put); /* Note this assumes addr is a function, which it currently always is. */ void symbol_put_addr(void *addr) { struct module *modaddr; unsigned long a = (unsigned long)dereference_function_descriptor(addr); if (core_kernel_text(a)) return; /* * Even though we hold a reference on the module; we still need to * disable preemption in order to safely traverse the data structure. */ preempt_disable(); modaddr = __module_text_address(a); BUG_ON(!modaddr); module_put(modaddr); preempt_enable(); } EXPORT_SYMBOL_GPL(symbol_put_addr); static ssize_t show_refcnt(struct module_attribute *mattr, struct module_kobject *mk, char *buffer) { return sprintf(buffer, "%i\n", module_refcount(mk->mod)); } static struct module_attribute modinfo_refcnt = __ATTR(refcnt, 0444, show_refcnt, NULL); void __module_get(struct module *module) { if (module) { preempt_disable(); atomic_inc(&module->refcnt); trace_module_get(module, _RET_IP_); preempt_enable(); } } EXPORT_SYMBOL(__module_get); bool try_module_get(struct module *module) { bool ret = true; if (module) { preempt_disable(); /* Note: here, we can fail to get a reference */ if (likely(module_is_live(module) && atomic_inc_not_zero(&module->refcnt) != 0)) trace_module_get(module, _RET_IP_); else ret = false; preempt_enable(); } return ret; } EXPORT_SYMBOL(try_module_get); void module_put(struct module *module) { int ret; if (module) { preempt_disable(); ret = atomic_dec_if_positive(&module->refcnt); WARN_ON(ret < 0); /* Failed to put refcount */ trace_module_put(module, _RET_IP_); preempt_enable(); } } EXPORT_SYMBOL(module_put); #else /* !CONFIG_MODULE_UNLOAD */ static inline void print_unload_info(struct seq_file *m, struct module *mod) { /* We don't know the usage count, or what modules are using. */ seq_puts(m, " - -"); } static inline void module_unload_free(struct module *mod) { } static int ref_module(struct module *a, struct module *b) { return strong_try_module_get(b); } static inline int module_unload_init(struct module *mod) { return 0; } #endif /* CONFIG_MODULE_UNLOAD */ static size_t module_flags_taint(struct module *mod, char *buf) { size_t l = 0; int i; for (i = 0; i < TAINT_FLAGS_COUNT; i++) { if (taint_flags[i].module && test_bit(i, &mod->taints)) buf[l++] = taint_flags[i].c_true; } return l; } static ssize_t show_initstate(struct module_attribute *mattr, struct module_kobject *mk, char *buffer) { const char *state = "unknown"; switch (mk->mod->state) { case MODULE_STATE_LIVE: state = "live"; break; case MODULE_STATE_COMING: state = "coming"; break; case MODULE_STATE_GOING: state = "going"; break; default: BUG(); } return sprintf(buffer, "%s\n", state); } static struct module_attribute modinfo_initstate = __ATTR(initstate, 0444, show_initstate, NULL); static ssize_t store_uevent(struct module_attribute *mattr, struct module_kobject *mk, const char *buffer, size_t count) { int rc; rc = kobject_synth_uevent(&mk->kobj, buffer, count); return rc ? rc : count; } struct module_attribute module_uevent = __ATTR(uevent, 0200, NULL, store_uevent); static ssize_t show_coresize(struct module_attribute *mattr, struct module_kobject *mk, char *buffer) { return sprintf(buffer, "%u\n", mk->mod->core_layout.size); } static struct module_attribute modinfo_coresize = __ATTR(coresize, 0444, show_coresize, NULL); static ssize_t show_initsize(struct module_attribute *mattr, struct module_kobject *mk, char *buffer) { return sprintf(buffer, "%u\n", mk->mod->init_layout.size); } static struct module_attribute modinfo_initsize = __ATTR(initsize, 0444, show_initsize, NULL); static ssize_t show_taint(struct module_attribute *mattr, struct module_kobject *mk, char *buffer) { size_t l; l = module_flags_taint(mk->mod, buffer); buffer[l++] = '\n'; return l; } static struct module_attribute modinfo_taint = __ATTR(taint, 0444, show_taint, NULL); static struct module_attribute *modinfo_attrs[] = { &module_uevent, &modinfo_version, &modinfo_srcversion, &modinfo_initstate, &modinfo_coresize, &modinfo_initsize, &modinfo_taint, #ifdef CONFIG_MODULE_UNLOAD &modinfo_refcnt, #endif NULL, }; static const char vermagic[] = VERMAGIC_STRING; static int try_to_force_load(struct module *mod, const char *reason) { #ifdef CONFIG_MODULE_FORCE_LOAD if (!test_taint(TAINT_FORCED_MODULE)) pr_warn("%s: %s: kernel tainted.\n", mod->name, reason); add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE); return 0; #else return -ENOEXEC; #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) { const s32 *crc; /* * 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("module_layout", NULL, &crc, NULL, true, false)) { preempt_enable(); BUG(); } preempt_enable(); return check_version(info, "module_layout", mod, 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); static int verify_namespace_is_imported(const struct load_info *info, const struct kernel_symbol *sym, struct module *mod) { const char *namespace; char *imported_namespace; namespace = kernel_symbol_namespace(sym); if (namespace && namespace[0]) { imported_namespace = get_modinfo(info, "import_ns"); while (imported_namespace) { if (strcmp(namespace, imported_namespace) == 0) return 0; imported_namespace = get_next_modinfo( info, "import_ns", imported_namespace); } #ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS pr_warn( #else pr_err( #endif "%s: module uses symbol (%s) from namespace %s, but does not import it.\n", mod->name, kernel_symbol_name(sym), namespace); #ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS return -EINVAL; #endif } return 0; } static bool inherit_taint(struct module *mod, struct module *owner) { if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints)) return true; if (mod->using_gplonly_symbols) { pr_err("%s: module using GPL-only symbols uses symbols from proprietary module %s.\n", mod->name, owner->name); return false; } if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) { pr_warn("%s: module uses symbols from proprietary module %s, inheriting taint.\n", mod->name, owner->name); set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints); } return true; } /* Resolve a symbol for this module. I.e. if we find one, record usage. */ static const struct kernel_symbol *resolve_symbol(struct module *mod, const struct load_info *info, const char *name, char ownername[]) { struct module *owner; const struct kernel_symbol *sym; const s32 *crc; enum mod_license license; int err; /* * The module_mutex should not be a heavily contended lock; * if we get the occasional sleep here, we'll go an extra iteration * in the wait_event_interruptible(), which is harmless. */ sched_annotate_sleep(); mutex_lock(&module_mutex); sym = find_symbol(name, &owner, &crc, &license, !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true); if (!sym) goto unlock; if (license == GPL_ONLY) mod->using_gplonly_symbols = true; if (!inherit_taint(mod, owner)) { sym = NULL; goto getname; } if (!check_version(info, name, mod, crc)) { sym = ERR_PTR(-EINVAL); goto getname; } err = verify_namespace_is_imported(info, sym, mod); if (err) { sym = ERR_PTR(err); goto getname; } err = ref_module(mod, owner); if (err) { sym = ERR_PTR(err); goto getname; } getname: /* We must make copy under the lock if we failed to get ref. */ strncpy(ownername, module_name(owner), MODULE_NAME_LEN); unlock: mutex_unlock(&module_mutex); return sym; } static const struct kernel_symbol * resolve_symbol_wait(struct module *mod, const struct load_info *info, const char *name) { const struct kernel_symbol *ksym; char owner[MODULE_NAME_LEN]; if (wait_event_interruptible_timeout(module_wq, !IS_ERR(ksym = resolve_symbol(mod, info, name, owner)) || PTR_ERR(ksym) != -EBUSY, 30 * HZ) <= 0) { pr_warn("%s: gave up waiting for init of module %s.\n", mod->name, owner); } return ksym; } /* * /sys/module/foo/sections stuff * J. Corbet */ #ifdef CONFIG_SYSFS #ifdef CONFIG_KALLSYMS static inline bool sect_empty(const Elf_Shdr *sect) { return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0; } struct module_sect_attr { struct bin_attribute battr; unsigned long address; }; struct module_sect_attrs { struct attribute_group grp; unsigned int nsections; struct module_sect_attr attrs[]; }; #define MODULE_SECT_READ_SIZE (3 /* "0x", "\n" */ + (BITS_PER_LONG / 4)) static ssize_t module_sect_read(struct file *file, struct kobject *kobj, struct bin_attribute *battr, char *buf, loff_t pos, size_t count) { struct module_sect_attr *sattr = container_of(battr, struct module_sect_attr, battr); char bounce[MODULE_SECT_READ_SIZE + 1]; size_t wrote; if (pos != 0) return -EINVAL; /* * Since we're a binary read handler, we must account for the * trailing NUL byte that sprintf will write: if "buf" is * too small to hold the NUL, or the NUL is exactly the last * byte, the read will look like it got truncated by one byte. * Since there is no way to ask sprintf nicely to not write * the NUL, we have to use a bounce buffer. */ wrote = scnprintf(bounce, sizeof(bounce), "0x%px\n", kallsyms_show_value(file->f_cred) ? (void *)sattr->address : NULL); count = min(count, wrote); memcpy(buf, bounce, count); return count; } static void free_sect_attrs(struct module_sect_attrs *sect_attrs) { unsigned int section; for (section = 0; section < sect_attrs->nsections; section++) kfree(sect_attrs->attrs[section].battr.attr.name); kfree(sect_attrs); } static void add_sect_attrs(struct module *mod, const struct load_info *info) { unsigned int nloaded = 0, i, size[2]; struct module_sect_attrs *sect_attrs; struct module_sect_attr *sattr; struct bin_attribute **gattr; /* Count loaded sections and allocate structures */ for (i = 0; i < info->hdr->e_shnum; i++) if (!sect_empty(&info->sechdrs[i])) nloaded++; size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded), sizeof(sect_attrs->grp.bin_attrs[0])); size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.bin_attrs[0]); sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL); if (sect_attrs == NULL) return; /* Setup section attributes. */ sect_attrs->grp.name = "sections"; sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0]; sect_attrs->nsections = 0; sattr = §_attrs->attrs[0]; gattr = §_attrs->grp.bin_attrs[0]; for (i = 0; i < info->hdr->e_shnum; i++) { Elf_Shdr *sec = &info->sechdrs[i]; if (sect_empty(sec)) continue; sysfs_bin_attr_init(&sattr->battr); sattr->address = sec->sh_addr; sattr->battr.attr.name = kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL); if (sattr->battr.attr.name == NULL) goto out; sect_attrs->nsections++; sattr->battr.read = module_sect_read; sattr->battr.size = MODULE_SECT_READ_SIZE; sattr->battr.attr.mode = 0400; *(gattr++) = &(sattr++)->battr; } *gattr = NULL; if (sysfs_create_group(&mod->mkobj.kobj, §_attrs->grp)) goto out; mod->sect_attrs = sect_attrs; return; out: free_sect_attrs(sect_attrs); } static void remove_sect_attrs(struct module *mod) { if (mod->sect_attrs) { sysfs_remove_group(&mod->mkobj.kobj, &mod->sect_attrs->grp); /* We are positive that no one is using any sect attrs * at this point. Deallocate immediately. */ free_sect_attrs(mod->sect_attrs); mod->sect_attrs = NULL; } } /* * /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections. */ struct module_notes_attrs { struct kobject *dir; unsigned int notes; struct bin_attribute attrs[]; }; static ssize_t module_notes_read(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t pos, size_t count) { /* * The caller checked the pos and count against our size. */ memcpy(buf, bin_attr->private + pos, count); return count; } static void free_notes_attrs(struct module_notes_attrs *notes_attrs, unsigned int i) { if (notes_attrs->dir) { while (i-- > 0) sysfs_remove_bin_file(notes_attrs->dir, ¬es_attrs->attrs[i]); kobject_put(notes_attrs->dir); } kfree(notes_attrs); } static void add_notes_attrs(struct module *mod, const struct load_info *info) { unsigned int notes, loaded, i; struct module_notes_attrs *notes_attrs; struct bin_attribute *nattr; /* failed to create section attributes, so can't create notes */ if (!mod->sect_attrs) return; /* Count notes sections and allocate structures. */ notes = 0; for (i = 0; i < info->hdr->e_shnum; i++) if (!sect_empty(&info->sechdrs[i]) && (info->sechdrs[i].sh_type == SHT_NOTE)) ++notes; if (notes == 0) return; notes_attrs = kzalloc(struct_size(notes_attrs, attrs, notes), GFP_KERNEL); if (notes_attrs == NULL) return; notes_attrs->notes = notes; nattr = ¬es_attrs->attrs[0]; for (loaded = i = 0; i < info->hdr->e_shnum; ++i) { if (sect_empty(&info->sechdrs[i])) continue; if (info->sechdrs[i].sh_type == SHT_NOTE) { sysfs_bin_attr_init(nattr); nattr->attr.name = mod->sect_attrs->attrs[loaded].battr.attr.name; nattr->attr.mode = S_IRUGO; nattr->size = info->sechdrs[i].sh_size; nattr->private = (void *) info->sechdrs[i].sh_addr; nattr->read = module_notes_read; ++nattr; } ++loaded; } notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj); if (!notes_attrs->dir) goto out; for (i = 0; i < notes; ++i) if (sysfs_create_bin_file(notes_attrs->dir, ¬es_attrs->attrs[i])) goto out; mod->notes_attrs = notes_attrs; return; out: free_notes_attrs(notes_attrs, i); } static void remove_notes_attrs(struct module *mod) { if (mod->notes_attrs) free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes); } #else static inline void add_sect_attrs(struct module *mod, const struct load_info *info) { } static inline void remove_sect_attrs(struct module *mod) { } static inline void add_notes_attrs(struct module *mod, const struct load_info *info) { } static inline void remove_notes_attrs(struct module *mod) { } #endif /* CONFIG_KALLSYMS */ static void del_usage_links(struct module *mod) { #ifdef CONFIG_MODULE_UNLOAD struct module_use *use; mutex_lock(&module_mutex); list_for_each_entry(use, &mod->target_list, target_list) sysfs_remove_link(use->target->holders_dir, mod->name); mutex_unlock(&module_mutex); #endif } static int add_usage_links(struct module *mod) { int ret = 0; #ifdef CONFIG_MODULE_UNLOAD struct module_use *use; mutex_lock(&module_mutex); list_for_each_entry(use, &mod->target_list, target_list) { ret = sysfs_create_link(use->target->holders_dir, &mod->mkobj.kobj, mod->name); if (ret) break; } mutex_unlock(&module_mutex); if (ret) del_usage_links(mod); #endif return ret; } static void module_remove_modinfo_attrs(struct module *mod, int end); static int module_add_modinfo_attrs(struct module *mod) { struct module_attribute *attr; struct module_attribute *temp_attr; int error = 0; int i; mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) * (ARRAY_SIZE(modinfo_attrs) + 1)), GFP_KERNEL); if (!mod->modinfo_attrs) return -ENOMEM; temp_attr = mod->modinfo_attrs; for (i = 0; (attr = modinfo_attrs[i]); i++) { if (!attr->test || attr->test(mod)) { memcpy(temp_attr, attr, sizeof(*temp_attr)); sysfs_attr_init(&temp_attr->attr); error = sysfs_create_file(&mod->mkobj.kobj, &temp_attr->attr); if (error) goto error_out; ++temp_attr; } } return 0; error_out: if (i > 0) module_remove_modinfo_attrs(mod, --i); else kfree(mod->modinfo_attrs); return error; } static void module_remove_modinfo_attrs(struct module *mod, int end) { struct module_attribute *attr; int i; for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) { if (end >= 0 && i > end) break; /* pick a field to test for end of list */ if (!attr->attr.name) break; sysfs_remove_file(&mod->mkobj.kobj, &attr->attr); if (attr->free) attr->free(mod); } kfree(mod->modinfo_attrs); } static void mod_kobject_put(struct module *mod) { DECLARE_COMPLETION_ONSTACK(c); mod->mkobj.kobj_completion = &c; kobject_put(&mod->mkobj.kobj); wait_for_completion(&c); } static int mod_sysfs_init(struct module *mod) { int err; struct kobject *kobj; if (!module_sysfs_initialized) { pr_err("%s: module sysfs not initialized\n", mod->name); err = -EINVAL; goto out; } kobj = kset_find_obj(module_kset, mod->name); if (kobj) { pr_err("%s: module is already loaded\n", mod->name); kobject_put(kobj); err = -EINVAL; goto out; } mod->mkobj.mod = mod; memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj)); mod->mkobj.kobj.kset = module_kset; err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL, "%s", mod->name); if (err) mod_kobject_put(mod); /* delay uevent until full sysfs population */ out: return err; } static int mod_sysfs_setup(struct module *mod, const struct load_info *info, struct kernel_param *kparam, unsigned int num_params) { int err; err = mod_sysfs_init(mod); if (err) goto out; mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj); if (!mod->holders_dir) { err = -ENOMEM; goto out_unreg; } err = module_param_sysfs_setup(mod, kparam, num_params); if (err) goto out_unreg_holders; err = module_add_modinfo_attrs(mod); if (err) goto out_unreg_param; err = add_usage_links(mod); if (err) goto out_unreg_modinfo_attrs; add_sect_attrs(mod, info); add_notes_attrs(mod, info); kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD); return 0; out_unreg_modinfo_attrs: module_remove_modinfo_attrs(mod, -1); out_unreg_param: module_param_sysfs_remove(mod); out_unreg_holders: kobject_put(mod->holders_dir); out_unreg: mod_kobject_put(mod); out: return err; } static void mod_sysfs_fini(struct module *mod) { remove_notes_attrs(mod); remove_sect_attrs(mod); mod_kobject_put(mod); } static void init_param_lock(struct module *mod) { mutex_init(&mod->param_lock); } #else /* !CONFIG_SYSFS */ static int mod_sysfs_setup(struct module *mod, const struct load_info *info, struct kernel_param *kparam, unsigned int num_params) { return 0; } static void mod_sysfs_fini(struct module *mod) { } static void module_remove_modinfo_attrs(struct module *mod, int end) { } static void del_usage_links(struct module *mod) { } static void init_param_lock(struct module *mod) { } #endif /* CONFIG_SYSFS */ static void mod_sysfs_teardown(struct module *mod) { del_usage_links(mod); module_remove_modinfo_attrs(mod, -1); module_param_sysfs_remove(mod); kobject_put(mod->mkobj.drivers_dir); kobject_put(mod->holders_dir); mod_sysfs_fini(mod); } /* * LKM RO/NX protection: protect module's text/ro-data * from modification and any data from execution. * * General layout of module is: * [text] [read-only-data] [ro-after-init] [writable data] * text_size -----^ ^ ^ ^ * ro_size ------------------------| | | * ro_after_init_size -----------------------------| | * size -----------------------------------------------------------| * * These values are always page-aligned (as is base) */ /* * Since some arches are moving towards PAGE_KERNEL module allocations instead * of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() outside of the * CONFIG_STRICT_MODULE_RWX block below because they are needed regardless of * whether we are strict. */ #ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX static void frob_text(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages)) { BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1)); set_memory((unsigned long)layout->base, layout->text_size >> PAGE_SHIFT); } static void module_enable_x(const struct module *mod) { frob_text(&mod->core_layout, set_memory_x); frob_text(&mod->init_layout, set_memory_x); } #else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ static void module_enable_x(const struct module *mod) { } #endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */ #ifdef CONFIG_STRICT_MODULE_RWX static void frob_rodata(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages)) { BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1)); BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1)); set_memory((unsigned long)layout->base + layout->text_size, (layout->ro_size - layout->text_size) >> PAGE_SHIFT); } static void frob_ro_after_init(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages)) { BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1)); BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1)); set_memory((unsigned long)layout->base + layout->ro_size, (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT); } static void frob_writable_data(const struct module_layout *layout, int (*set_memory)(unsigned long start, int num_pages)) { BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1)); BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1)); BUG_ON((unsigned long)layout->size & (PAGE_SIZE-1)); set_memory((unsigned long)layout->base + layout->ro_after_init_size, (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT); } static void module_enable_ro(const struct module *mod, bool after_init) { if (!rodata_enabled) return; set_vm_flush_reset_perms(mod->core_layout.base); set_vm_flush_reset_perms(mod->init_layout.base); frob_text(&mod->core_layout, set_memory_ro); frob_rodata(&mod->core_layout, set_memory_ro); frob_text(&mod->init_layout, set_memory_ro); frob_rodata(&mod->init_layout, set_memory_ro); if (after_init) frob_ro_after_init(&mod->core_layout, set_memory_ro); } static void module_enable_nx(const struct module *mod) { frob_rodata(&mod->core_layout, set_memory_nx); frob_ro_after_init(&mod->core_layout, set_memory_nx); frob_writable_data(&mod->core_layout, set_memory_nx); frob_rodata(&mod->init_layout, set_memory_nx); frob_writable_data(&mod->init_layout, set_memory_nx); } static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, char *secstrings, struct module *mod) { const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR; int i; for (i = 0; i < hdr->e_shnum; i++) { if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) return -ENOEXEC; } return 0; } #else /* !CONFIG_STRICT_MODULE_RWX */ static void module_enable_nx(const struct module *mod) { } static void module_enable_ro(const struct module *mod, bool after_init) {} static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, char *secstrings, struct module *mod) { return 0; } #endif /* CONFIG_STRICT_MODULE_RWX */ #ifdef CONFIG_LIVEPATCH /* * Persist Elf information about a module. Copy the Elf header, * section header table, section string table, and symtab section * index from info to mod->klp_info. */ static int copy_module_elf(struct module *mod, struct load_info *info) { unsigned int size, symndx; int ret; size = sizeof(*mod->klp_info); mod->klp_info = kmalloc(size, GFP_KERNEL); if (mod->klp_info == NULL) return -ENOMEM; /* Elf header */ size = sizeof(mod->klp_info->hdr); memcpy(&mod->klp_info->hdr, info->hdr, size); /* Elf section header table */ size = sizeof(*info->sechdrs) * info->hdr->e_shnum; mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL); if (mod->klp_info->sechdrs == NULL) { ret = -ENOMEM; goto free_info; } /* Elf section name string table */ size = info->sechdrs[info->hdr->e_shstrndx].sh_size; mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL); if (mod->klp_info->secstrings == NULL) { ret = -ENOMEM; goto free_sechdrs; } /* Elf symbol section index */ symndx = info->index.sym; mod->klp_info->symndx = symndx; /* * For livepatch modules, core_kallsyms.symtab is a complete * copy of the original symbol table. Adjust sh_addr to point * to core_kallsyms.symtab since the copy of the symtab in module * init memory is freed at the end of do_init_module(). */ mod->klp_info->sechdrs[symndx].sh_addr = \ (unsigned long) mod->core_kallsyms.symtab; return 0; free_sechdrs: kfree(mod->klp_info->sechdrs); free_info: kfree(mod->klp_info); return ret; } static void free_module_elf(struct module *mod) { kfree(mod->klp_info->sechdrs); kfree(mod->klp_info->secstrings); kfree(mod->klp_info); } #else /* !CONFIG_LIVEPATCH */ static int copy_module_elf(struct module *mod, struct load_info *info) { return 0; } static void free_module_elf(struct module *mod) { } #endif /* CONFIG_LIVEPATCH */ void __weak module_memfree(void *module_region) { /* * This memory may be RO, and freeing RO memory in an interrupt is not * supported by vmalloc. */ WARN_ON(in_interrupt()); vfree(module_region); } void __weak module_arch_cleanup(struct module *mod) { } void __weak module_arch_freeing_init(struct module *mod) { } /* Free a module, remove from lists, etc. */ static void free_module(struct module *mod) { trace_module_free(mod); mod_sysfs_teardown(mod); /* We leave it in list to prevent duplicate loads, but make sure * that noone uses it while it's being deconstructed. */ mutex_lock(&module_mutex); mod->state = MODULE_STATE_UNFORMED; mutex_unlock(&module_mutex); /* Remove dynamic debug info */ ddebug_remove_module(mod->name); /* Arch-specific cleanup. */ module_arch_cleanup(mod); /* Module unload stuff */ module_unload_free(mod); /* Free any allocated parameters. */ destroy_params(mod->kp, mod->num_kp); if (is_livepatch_module(mod)) free_module_elf(mod); /* Now we can delete it from the lists */ mutex_lock(&module_mutex); /* Unlink carefully: kallsyms could be walking list. */ list_del_rcu(&mod->list); mod_tree_remove(mod); /* Remove this module from bug list, this uses list_del_rcu */ module_bug_cleanup(mod); /* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */ synchronize_rcu(); mutex_unlock(&module_mutex); /* This may be empty, but that's OK */ module_arch_freeing_init(mod); module_memfree(mod->init_layout.base); kfree(mod->args); percpu_modfree(mod); /* Free lock-classes; relies on the preceding sync_rcu(). */ lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size); /* Finally, free the core (containing the module structure) */ module_memfree(mod->core_layout.base); } void *__symbol_get(const char *symbol) { struct module *owner; const struct kernel_symbol *sym; preempt_disable(); sym = find_symbol(symbol, &owner, NULL, NULL, true, true); if (sym && strong_try_module_get(owner)) sym = NULL; preempt_enable(); return sym ? (void *)kernel_symbol_value(sym) : NULL; } EXPORT_SYMBOL_GPL(__symbol_get); /* * Ensure that an exported symbol [global namespace] does not already exist * in the kernel or in some other module's exported symbol table. * * You must hold the module_mutex. */ static int verify_exported_symbols(struct module *mod) { unsigned int i; struct module *owner; const struct kernel_symbol *s; struct { const struct kernel_symbol *sym; unsigned int num; } arr[] = { { mod->syms, mod->num_syms }, { mod->gpl_syms, mod->num_gpl_syms }, { mod->gpl_future_syms, mod->num_gpl_future_syms }, #ifdef CONFIG_UNUSED_SYMBOLS { mod->unused_syms, mod->num_unused_syms }, { mod->unused_gpl_syms, mod->num_unused_gpl_syms }, #endif }; for (i = 0; i < ARRAY_SIZE(arr); i++) { for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) { if (find_symbol(kernel_symbol_name(s), &owner, NULL, NULL, true, false)) { pr_err("%s: exports duplicate symbol %s" " (owned by %s)\n", mod->name, kernel_symbol_name(s), module_name(owner)); return -ENOEXEC; } } } return 0; } /* Change all symbols so that st_value encodes the pointer directly. */ static int simplify_symbols(struct module *mod, const struct load_info *info) { Elf_Shdr *symsec = &info->sechdrs[info->index.sym]; Elf_Sym *sym = (void *)symsec->sh_addr; unsigned long secbase; unsigned int i; int ret = 0; const struct kernel_symbol *ksym; for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) { const char *name = info->strtab + sym[i].st_name; switch (sym[i].st_shndx) { case SHN_COMMON: /* Ignore common symbols */ if (!strncmp(name, "__gnu_lto", 9)) break; /* We compiled with -fno-common. These are not supposed to happen. */ pr_debug("Common symbol: %s\n", name); pr_warn("%s: please compile with -fno-common\n", mod->name); ret = -ENOEXEC; break; case SHN_ABS: /* Don't need to do anything */ pr_debug("Absolute symbol: 0x%08lx\n", (long)sym[i].st_value); break; case SHN_LIVEPATCH: /* Livepatch symbols are resolved by livepatch */ break; case SHN_UNDEF: ksym = resolve_symbol_wait(mod, info, name); /* Ok if resolved. */ if (ksym && !IS_ERR(ksym)) { sym[i].st_value = kernel_symbol_value(ksym); break; } /* Ok if weak. */ if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK) break; ret = PTR_ERR(ksym) ?: -ENOENT; pr_warn("%s: Unknown symbol %s (err %d)\n", mod->name, name, ret); break; default: /* Divert to percpu allocation if a percpu var. */ if (sym[i].st_shndx == info->index.pcpu) secbase = (unsigned long)mod_percpu(mod); else secbase = info->sechdrs[sym[i].st_shndx].sh_addr; sym[i].st_value += secbase; break; } } return ret; } static int apply_relocations(struct module *mod, const struct load_info *info) { unsigned int i; int err = 0; /* Now do relocations. */ for (i = 1; i < info->hdr->e_shnum; i++) { unsigned int infosec = info->sechdrs[i].sh_info; /* Not a valid relocation section? */ if (infosec >= info->hdr->e_shnum) continue; /* Don't bother with non-allocated sections */ if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC)) continue; if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH) err = klp_apply_section_relocs(mod, info->sechdrs, info->secstrings, info->strtab, info->index.sym, i, NULL); else if (info->sechdrs[i].sh_type == SHT_REL) err = apply_relocate(info->sechdrs, info->strtab, info->index.sym, i, mod); else if (info->sechdrs[i].sh_type == SHT_RELA) err = apply_relocate_add(info->sechdrs, info->strtab, info->index.sym, i, mod); if (err < 0) break; } return err; } /* Additional bytes needed by arch in front of individual sections */ unsigned int __weak arch_mod_section_prepend(struct module *mod, unsigned int section) { /* default implementation just returns zero */ return 0; } /* Update size with this section: return offset. */ static long get_offset(struct module *mod, unsigned int *size, Elf_Shdr *sechdr, unsigned int section) { long ret; *size += arch_mod_section_prepend(mod, section); ret = ALIGN(*size, sechdr->sh_addralign ?: 1); *size = ret + sechdr->sh_size; return ret; } /* Lay out the SHF_ALLOC sections in a way not dissimilar to how ld might -- code, read-only data, read-write data, small data. Tally sizes, and place the offsets into sh_entsize fields: high bit means it belongs in init. */ static void layout_sections(struct module *mod, struct load_info *info) { static unsigned long const masks[][2] = { /* NOTE: all executable code must be the first section * in this array; otherwise modify the text_size * finder in the two loops below */ { SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL }, { SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL }, { SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL }, { SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL }, { ARCH_SHF_SMALL | SHF_ALLOC, 0 } }; unsigned int m, i; for (i = 0; i < info->hdr->e_shnum; i++) info->sechdrs[i].sh_entsize = ~0UL; pr_debug("Core section allocation order:\n"); for (m = 0; m < ARRAY_SIZE(masks); ++m) { for (i = 0; i < info->hdr->e_shnum; ++i) { Elf_Shdr *s = &info->sechdrs[i]; const char *sname = info->secstrings + s->sh_name; if ((s->sh_flags & masks[m][0]) != masks[m][0] || (s->sh_flags & masks[m][1]) || s->sh_entsize != ~0UL || module_init_section(sname)) continue; s->sh_entsize = get_offset(mod, &mod->core_layout.size, s, i); pr_debug("\t%s\n", sname); } switch (m) { case 0: /* executable */ mod->core_layout.size = debug_align(mod->core_layout.size); mod->core_layout.text_size = mod->core_layout.size; break; case 1: /* RO: text and ro-data */ mod->core_layout.size = debug_align(mod->core_layout.size); mod->core_layout.ro_size = mod->core_layout.size; break; case 2: /* RO after init */ mod->core_layout.size = debug_align(mod->core_layout.size); mod->core_layout.ro_after_init_size = mod->core_layout.size; break; case 4: /* whole core */ mod->core_layout.size = debug_align(mod->core_layout.size); break; } } pr_debug("Init section allocation order:\n"); for (m = 0; m < ARRAY_SIZE(masks); ++m) { for (i = 0; i < info->hdr->e_shnum; ++i) { Elf_Shdr *s = &info->sechdrs[i]; const char *sname = info->secstrings + s->sh_name; if ((s->sh_flags & masks[m][0]) != masks[m][0] || (s->sh_flags & masks[m][1]) || s->sh_entsize != ~0UL || !module_init_section(sname)) continue; s->sh_entsize = (get_offset(mod, &mod->init_layout.size, s, i) | INIT_OFFSET_MASK); pr_debug("\t%s\n", sname); } switch (m) { case 0: /* executable */ mod->init_layout.size = debug_align(mod->init_layout.size); mod->init_layout.text_size = mod->init_layout.size; break; case 1: /* RO: text and ro-data */ mod->init_layout.size = debug_align(mod->init_layout.size); mod->init_layout.ro_size = mod->init_layout.size; break; case 2: /* * RO after init doesn't apply to init_layout (only * core_layout), so it just takes the value of ro_size. */ mod->init_layout.ro_after_init_size = mod->init_layout.ro_size; break; case 4: /* whole init */ mod->init_layout.size = debug_align(mod->init_layout.size); break; } } } static void set_license(struct module *mod, const char *license) { if (!license) license = "unspecified"; if (!license_is_gpl_compatible(license)) { if (!test_taint(TAINT_PROPRIETARY_MODULE)) pr_warn("%s: module license '%s' taints kernel.\n", mod->name, license); add_taint_module(mod, TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE); } } /* Parse tag=value strings from .modinfo section */ static char *next_string(char *string, unsigned long *secsize) { /* Skip non-zero chars */ while (string[0]) { string++; if ((*secsize)-- <= 1) return NULL; } /* Skip any zero padding. */ while (!string[0]) { string++; if ((*secsize)-- <= 1) return NULL; } return string; } static char *get_next_modinfo(const struct load_info *info, const char *tag, char *prev) { char *p; unsigned int taglen = strlen(tag); Elf_Shdr *infosec = &info->sechdrs[info->index.info]; unsigned long size = infosec->sh_size; /* * get_modinfo() calls made before rewrite_section_headers() * must use sh_offset, as sh_addr isn't set! */ char *modinfo = (char *)info->hdr + infosec->sh_offset; if (prev) { size -= prev - modinfo; modinfo = next_string(prev, &size); } for (p = modinfo; p; p = next_string(p, &size)) { if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') return p + taglen + 1; } return NULL; } static char *get_modinfo(const struct load_info *info, const char *tag) { return get_next_modinfo(info, tag, NULL); } static void setup_modinfo(struct module *mod, struct load_info *info) { struct module_attribute *attr; int i; for (i = 0; (attr = modinfo_attrs[i]); i++) { if (attr->setup) attr->setup(mod, get_modinfo(info, attr->attr.name)); } } static void free_modinfo(struct module *mod) { struct module_attribute *attr; int i; for (i = 0; (attr = modinfo_attrs[i]); i++) { if (attr->free) attr->free(mod); } } #ifdef CONFIG_KALLSYMS /* Lookup exported symbol in given range of kernel_symbols */ static const struct kernel_symbol *lookup_exported_symbol(const char *name, const struct kernel_symbol *start, const struct kernel_symbol *stop) { return bsearch(name, start, stop - start, sizeof(struct kernel_symbol), cmp_name); } static int is_exported(const char *name, unsigned long value, const struct module *mod) { const struct kernel_symbol *ks; if (!mod) ks = lookup_exported_symbol(name, __start___ksymtab, __stop___ksymtab); else ks = lookup_exported_symbol(name, mod->syms, mod->syms + mod->num_syms); return ks != NULL && kernel_symbol_value(ks) == value; } /* As per nm */ static char elf_type(const Elf_Sym *sym, const struct load_info *info) { const Elf_Shdr *sechdrs = info->sechdrs; if (ELF_ST_BIND(sym->st_info) == STB_WEAK) { if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT) return 'v'; else return 'w'; } if (sym->st_shndx == SHN_UNDEF) return 'U'; if (sym->st_shndx == SHN_ABS || sym->st_shndx == info->index.pcpu) return 'a'; if (sym->st_shndx >= SHN_LORESERVE) return '?'; if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR) return 't'; if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC && sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) { if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE)) return 'r'; else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL) return 'g'; else return 'd'; } if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) { if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL) return 's'; else return 'b'; } if (strstarts(info->secstrings + sechdrs[sym->st_shndx].sh_name, ".debug")) { return 'n'; } return '?'; } static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs, unsigned int shnum, unsigned int pcpundx) { const Elf_Shdr *sec; if (src->st_shndx == SHN_UNDEF || src->st_shndx >= shnum || !src->st_name) return false; #ifdef CONFIG_KALLSYMS_ALL if (src->st_shndx == pcpundx) return true; #endif sec = sechdrs + src->st_shndx; if (!(sec->sh_flags & SHF_ALLOC) #ifndef CONFIG_KALLSYMS_ALL || !(sec->sh_flags & SHF_EXECINSTR) #endif || (sec->sh_entsize & INIT_OFFSET_MASK)) return false; return true; } /* * We only allocate and copy the strings needed by the parts of symtab * we keep. This is simple, but has the effect of making multiple * copies of duplicates. We could be more sophisticated, see * linux-kernel thread starting with * <73defb5e4bca04a6431392cc341112b1@localhost>. */ static void layout_symtab(struct module *mod, struct load_info *info) { Elf_Shdr *symsect = info->sechdrs + info->index.sym; Elf_Shdr *strsect = info->sechdrs + info->index.str; const Elf_Sym *src; unsigned int i, nsrc, ndst, strtab_size = 0; /* Put symbol section at end of init part of module. */ symsect->sh_flags |= SHF_ALLOC; symsect->sh_entsize = get_offset(mod, &mod->init_layout.size, symsect, info->index.sym) | INIT_OFFSET_MASK; pr_debug("\t%s\n", info->secstrings + symsect->sh_name); src = (void *)info->hdr + symsect->sh_offset; nsrc = symsect->sh_size / sizeof(*src); /* Compute total space required for the core symbols' strtab. */ for (ndst = i = 0; i < nsrc; i++) { if (i == 0 || is_livepatch_module(mod) || is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum, info->index.pcpu)) { strtab_size += strlen(&info->strtab[src[i].st_name])+1; ndst++; } } /* Append room for core symbols at end of core part. */ info->symoffs = ALIGN(mod->core_layout.size, symsect->sh_addralign ?: 1); info->stroffs = mod->core_layout.size = info->symoffs + ndst * sizeof(Elf_Sym); mod->core_layout.size += strtab_size; info->core_typeoffs = mod->core_layout.size; mod->core_layout.size += ndst * sizeof(char); mod->core_layout.size = debug_align(mod->core_layout.size); /* Put string table section at end of init part of module. */ strsect->sh_flags |= SHF_ALLOC; strsect->sh_entsize = get_offset(mod, &mod->init_layout.size, strsect, info->index.str) | INIT_OFFSET_MASK; pr_debug("\t%s\n", info->secstrings + strsect->sh_name); /* We'll tack temporary mod_kallsyms on the end. */ mod->init_layout.size = ALIGN(mod->init_layout.size, __alignof__(struct mod_kallsyms)); info->mod_kallsyms_init_off = mod->init_layout.size; mod->init_layout.size += sizeof(struct mod_kallsyms); info->init_typeoffs = mod->init_layout.size; mod->init_layout.size += nsrc * sizeof(char); mod->init_layout.size = debug_align(mod->init_layout.size); } /* * We use the full symtab and strtab which layout_symtab arranged to * be appended to the init section. Later we switch to the cut-down * core-only ones. */ static void add_kallsyms(struct module *mod, const struct load_info *info) { unsigned int i, ndst; const Elf_Sym *src; Elf_Sym *dst; char *s; Elf_Shdr *symsec = &info->sechdrs[info->index.sym]; /* Set up to point into init section. */ mod->kallsyms = mod->init_layout.base + info->mod_kallsyms_init_off; mod->kallsyms->symtab = (void *)symsec->sh_addr; mod->kallsyms->num_symtab = symsec->sh_size / sizeof(Elf_Sym); /* Make sure we get permanent strtab: don't use info->strtab. */ mod->kallsyms->strtab = (void *)info->sechdrs[info->index.str].sh_addr; mod->kallsyms->typetab = mod->init_layout.base + info->init_typeoffs; /* * Now populate the cut down core kallsyms for after init * and set types up while we still have access to sections. */ mod->core_kallsyms.symtab = dst = mod->core_layout.base + info->symoffs; mod->core_kallsyms.strtab = s = mod->core_layout.base + info->stroffs; mod->core_kallsyms.typetab = mod->core_layout.base + info->core_typeoffs; src = mod->kallsyms->symtab; for (ndst = i = 0; i < mod->kallsyms->num_symtab; i++) { mod->kallsyms->typetab[i] = elf_type(src + i, info); if (i == 0 || is_livepatch_module(mod) || is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum, info->index.pcpu)) { mod->core_kallsyms.typetab[ndst] = mod->kallsyms->typetab[i]; dst[ndst] = src[i]; dst[ndst++].st_name = s - mod->core_kallsyms.strtab; s += strlcpy(s, &mod->kallsyms->strtab[src[i].st_name], KSYM_NAME_LEN) + 1; } } mod->core_kallsyms.num_symtab = ndst; } #else static inline void layout_symtab(struct module *mod, struct load_info *info) { } static void add_kallsyms(struct module *mod, const struct load_info *info) { } #endif /* CONFIG_KALLSYMS */ static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num) { if (!debug) return; ddebug_add_module(debug, num, mod->name); } static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug) { if (debug) ddebug_remove_module(mod->name); } void * __weak module_alloc(unsigned long size) { return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS, NUMA_NO_NODE, __builtin_return_address(0)); } bool __weak module_init_section(const char *name) { return strstarts(name, ".init"); } bool __weak module_exit_section(const char *name) { return strstarts(name, ".exit"); } #ifdef CONFIG_DEBUG_KMEMLEAK static void kmemleak_load_module(const struct module *mod, const struct load_info *info) { unsigned int i; /* only scan the sections containing data */ kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL); for (i = 1; i < info->hdr->e_shnum; i++) { /* Scan all writable sections that's not executable */ if (!(info->sechdrs[i].sh_flags & SHF_ALLOC) || !(info->sechdrs[i].sh_flags & SHF_WRITE) || (info->sechdrs[i].sh_flags & SHF_EXECINSTR)) continue; kmemleak_scan_area((void *)info->sechdrs[i].sh_addr, info->sechdrs[i].sh_size, GFP_KERNEL); } } #else static inline void kmemleak_load_module(const struct module *mod, const struct load_info *info) { } #endif #ifdef CONFIG_MODULE_SIG static int module_sig_check(struct load_info *info, int flags) { int err = -ENODATA; const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; const char *reason; const void *mod = info->hdr; /* * Require flags == 0, as a module with version information * removed is no longer the module that was signed */ if (flags == 0 && info->len > markerlen && memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) { /* We truncate the module to discard the signature */ info->len -= markerlen; err = mod_verify_sig(mod, info); } switch (err) { case 0: info->sig_ok = true; return 0; /* We don't permit modules to be loaded into trusted kernels * without a valid signature on them, but if we're not * enforcing, certain errors are non-fatal. */ case -ENODATA: reason = "Loading of unsigned module"; goto decide; case -ENOPKG: reason = "Loading of module with unsupported crypto"; goto decide; case -ENOKEY: reason = "Loading of module with unavailable key"; decide: if (is_module_sig_enforced()) { pr_notice("%s: %s is rejected\n", info->name, reason); return -EKEYREJECTED; } return security_locked_down(LOCKDOWN_MODULE_SIGNATURE); /* All other errors are fatal, including nomem, unparseable * signatures and signature check failures - even if signatures * aren't required. */ default: return err; } } #else /* !CONFIG_MODULE_SIG */ static int module_sig_check(struct load_info *info, int flags) { return 0; } #endif /* !CONFIG_MODULE_SIG */ /* Sanity checks against invalid binaries, wrong arch, weird elf version. */ static int elf_header_check(struct load_info *info) { if (info->len < sizeof(*(info->hdr))) return -ENOEXEC; if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0 || info->hdr->e_type != ET_REL || !elf_check_arch(info->hdr) || info->hdr->e_shentsize != sizeof(Elf_Shdr)) return -ENOEXEC; if (info->hdr->e_shoff >= info->len || (info->hdr->e_shnum * sizeof(Elf_Shdr) > info->len - info->hdr->e_shoff)) return -ENOEXEC; return 0; } #define COPY_CHUNK_SIZE (16*PAGE_SIZE) static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned long len) { do { unsigned long n = min(len, COPY_CHUNK_SIZE); if (copy_from_user(dst, usrc, n) != 0) return -EFAULT; cond_resched(); dst += n; usrc += n; len -= n; } while (len); return 0; } #ifdef CONFIG_LIVEPATCH static int check_modinfo_livepatch(struct module *mod, struct load_info *info) { if (get_modinfo(info, "livepatch")) { mod->klp = true; add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK); pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n", mod->name); } return 0; } #else /* !CONFIG_LIVEPATCH */ static int check_modinfo_livepatch(struct module *mod, struct load_info *info) { if (get_modinfo(info, "livepatch")) { pr_err("%s: module is marked as livepatch module, but livepatch support is disabled", mod->name); return -ENOEXEC; } return 0; } #endif /* CONFIG_LIVEPATCH */ static void check_modinfo_retpoline(struct module *mod, struct load_info *info) { if (retpoline_module_ok(get_modinfo(info, "retpoline"))) return; pr_warn("%s: loading module not compiled with retpoline compiler.\n", mod->name); } /* Sets info->hdr and info->len. */ static int copy_module_from_user(const void __user *umod, unsigned long len, struct load_info *info) { int err; info->len = len; if (info->len < sizeof(*(info->hdr))) return -ENOEXEC; err = security_kernel_load_data(LOADING_MODULE, true); if (err) return err; /* Suck in entire file: we'll want most of it. */ info->hdr = __vmalloc(info->len, GFP_KERNEL | __GFP_NOWARN); if (!info->hdr) return -ENOMEM; if (copy_chunked_from_user(info->hdr, umod, info->len) != 0) { err = -EFAULT; goto out; } err = security_kernel_post_load_data((char *)info->hdr, info->len, LOADING_MODULE, "init_module"); out: if (err) vfree(info->hdr); return err; } static void free_copy(struct load_info *info) { vfree(info->hdr); } static int rewrite_section_headers(struct load_info *info, int flags) { unsigned int i; /* This should always be true, but let's be sure. */ info->sechdrs[0].sh_addr = 0; for (i = 1; i < info->hdr->e_shnum; i++) { Elf_Shdr *shdr = &info->sechdrs[i]; if (shdr->sh_type != SHT_NOBITS && info->len < shdr->sh_offset + shdr->sh_size) { pr_err("Module len %lu truncated\n", info->len); return -ENOEXEC; } /* Mark all sections sh_addr with their address in the temporary image. */ shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset; #ifndef CONFIG_MODULE_UNLOAD /* Don't load .exit sections */ if (module_exit_section(info->secstrings+shdr->sh_name)) shdr->sh_flags &= ~(unsigned long)SHF_ALLOC; #endif } /* Track but don't keep modinfo and version sections. */ info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC; info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC; return 0; } /* * Set up our basic convenience variables (pointers to section headers, * search for module section index etc), and do some basic section * verification. * * Set info->mod to the temporary copy of the module in info->hdr. The final one * will be allocated in move_module(). */ static int setup_load_info(struct load_info *info, int flags) { unsigned int i; /* Set up the convenience variables */ info->sechdrs = (void *)info->hdr + info->hdr->e_shoff; info->secstrings = (void *)info->hdr + info->sechdrs[info->hdr->e_shstrndx].sh_offset; /* Try to find a name early so we can log errors with a module name */ info->index.info = find_sec(info, ".modinfo"); if (info->index.info) info->name = get_modinfo(info, "name"); /* Find internal symbols and strings. */ for (i = 1; i < info->hdr->e_shnum; i++) { if (info->sechdrs[i].sh_type == SHT_SYMTAB) { info->index.sym = i; info->index.str = info->sechdrs[i].sh_link; info->strtab = (char *)info->hdr + info->sechdrs[info->index.str].sh_offset; break; } } if (info->index.sym == 0) { pr_warn("%s: module has no symbols (stripped?)\n", info->name ?: "(missing .modinfo section or name field)"); return -ENOEXEC; } info->index.mod = find_sec(info, ".gnu.linkonce.this_module"); if (!info->index.mod) { pr_warn("%s: No module found in object\n", info->name ?: "(missing .modinfo section or name field)"); return -ENOEXEC; } /* This is temporary: point mod into copy of data. */ info->mod = (void *)info->hdr + info->sechdrs[info->index.mod].sh_offset; /* * If we didn't load the .modinfo 'name' field earlier, fall back to * on-disk struct mod 'name' field. */ if (!info->name) info->name = info->mod->name; if (flags & MODULE_INIT_IGNORE_MODVERSIONS) info->index.vers = 0; /* Pretend no __versions section! */ else info->index.vers = find_sec(info, "__versions"); info->index.pcpu = find_pcpusec(info); return 0; } static int check_modinfo(struct module *mod, struct load_info *info, int flags) { const char *modmagic = get_modinfo(info, "vermagic"); int err; if (flags & MODULE_INIT_IGNORE_VERMAGIC) modmagic = NULL; /* This is allowed: modprobe --force will invalidate it. */ if (!modmagic) { err = try_to_force_load(mod, "bad vermagic"); if (err) return err; } else if (!same_magic(modmagic, vermagic, info->index.vers)) { pr_err("%s: version magic '%s' should be '%s'\n", info->name, modmagic, vermagic); return -ENOEXEC; } if (!get_modinfo(info, "intree")) { if (!test_taint(TAINT_OOT_MODULE)) pr_warn("%s: loading out-of-tree module taints kernel.\n", mod->name); add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK); } check_modinfo_retpoline(mod, info); if (get_modinfo(info, "staging")) { add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK); pr_warn("%s: module is from the staging directory, the quality " "is unknown, you have been warned.\n", mod->name); } err = check_modinfo_livepatch(mod, info); if (err) return err; /* Set up license info based on the info section */ set_license(mod, get_modinfo(info, "license")); return 0; } static int find_module_sections(struct module *mod, struct load_info *info) { mod->kp = section_objs(info, "__param", sizeof(*mod->kp), &mod->num_kp); mod->syms = section_objs(info, "__ksymtab", sizeof(*mod->syms), &mod->num_syms); mod->crcs = section_addr(info, "__kcrctab"); mod->gpl_syms = section_objs(info, "__ksymtab_gpl", sizeof(*mod->gpl_syms), &mod->num_gpl_syms); mod->gpl_crcs = section_addr(info, "__kcrctab_gpl"); mod->gpl_future_syms = section_objs(info, "__ksymtab_gpl_future", sizeof(*mod->gpl_future_syms), &mod->num_gpl_future_syms); mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future"); #ifdef CONFIG_UNUSED_SYMBOLS mod->unused_syms = section_objs(info, "__ksymtab_unused", sizeof(*mod->unused_syms), &mod->num_unused_syms); mod->unused_crcs = section_addr(info, "__kcrctab_unused"); mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl", sizeof(*mod->unused_gpl_syms), &mod->num_unused_gpl_syms); mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl"); #endif #ifdef CONFIG_CONSTRUCTORS mod->ctors = section_objs(info, ".ctors", sizeof(*mod->ctors), &mod->num_ctors); if (!mod->ctors) mod->ctors = section_objs(info, ".init_array", sizeof(*mod->ctors), &mod->num_ctors); else if (find_sec(info, ".init_array")) { /* * This shouldn't happen with same compiler and binutils * building all parts of the module. */ pr_warn("%s: has both .ctors and .init_array.\n", mod->name); return -EINVAL; } #endif mod->noinstr_text_start = section_objs(info, ".noinstr.text", 1, &mod->noinstr_text_size); #ifdef CONFIG_TRACEPOINTS mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs", sizeof(*mod->tracepoints_ptrs), &mod->num_tracepoints); #endif #ifdef CONFIG_TREE_SRCU mod->srcu_struct_ptrs = section_objs(info, "___srcu_struct_ptrs", sizeof(*mod->srcu_struct_ptrs), &mod->num_srcu_structs); #endif #ifdef CONFIG_BPF_EVENTS mod->bpf_raw_events = section_objs(info, "__bpf_raw_tp_map", sizeof(*mod->bpf_raw_events), &mod->num_bpf_raw_events); #endif #ifdef CONFIG_JUMP_LABEL mod->jump_entries = section_objs(info, "__jump_table", sizeof(*mod->jump_entries), &mod->num_jump_entries); #endif #ifdef CONFIG_EVENT_TRACING mod->trace_events = section_objs(info, "_ftrace_events", sizeof(*mod->trace_events), &mod->num_trace_events); mod->trace_evals = section_objs(info, "_ftrace_eval_map", sizeof(*mod->trace_evals), &mod->num_trace_evals); #endif #ifdef CONFIG_TRACING mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt", sizeof(*mod->trace_bprintk_fmt_start), &mod->num_trace_bprintk_fmt); #endif #ifdef CONFIG_FTRACE_MCOUNT_RECORD /* sechdrs[0].sh_size is always zero */ mod->ftrace_callsites = section_objs(info, FTRACE_CALLSITE_SECTION, sizeof(*mod->ftrace_callsites), &mod->num_ftrace_callsites); #endif #ifdef CONFIG_FUNCTION_ERROR_INJECTION mod->ei_funcs = section_objs(info, "_error_injection_whitelist", sizeof(*mod->ei_funcs), &mod->num_ei_funcs); #endif #ifdef CONFIG_KPROBES mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1, &mod->kprobes_text_size); mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist", sizeof(unsigned long), &mod->num_kprobe_blacklist); #endif mod->extable = section_objs(info, "__ex_table", sizeof(*mod->extable), &mod->num_exentries); if (section_addr(info, "__obsparm")) pr_warn("%s: Ignoring obsolete parameters\n", mod->name); info->debug = section_objs(info, "__dyndbg", sizeof(*info->debug), &info->num_debug); return 0; } static int move_module(struct module *mod, struct load_info *info) { int i; void *ptr; /* Do the allocs. */ ptr = module_alloc(mod->core_layout.size); /* * The pointer to this block is stored in the module structure * which is inside the block. Just mark it as not being a * leak. */ kmemleak_not_leak(ptr); if (!ptr) return -ENOMEM; memset(ptr, 0, mod->core_layout.size); mod->core_layout.base = ptr; if (mod->init_layout.size) { ptr = module_alloc(mod->init_layout.size); /* * The pointer to this block is stored in the module structure * which is inside the block. This block doesn't need to be * scanned as it contains data and code that will be freed * after the module is initialized. */ kmemleak_ignore(ptr); if (!ptr) { module_memfree(mod->core_layout.base); return -ENOMEM; } memset(ptr, 0, mod->init_layout.size); mod->init_layout.base = ptr; } else mod->init_layout.base = NULL; /* Transfer each section which specifies SHF_ALLOC */ pr_debug("final section addresses:\n"); for (i = 0; i < info->hdr->e_shnum; i++) { void *dest; Elf_Shdr *shdr = &info->sechdrs[i]; if (!(shdr->sh_flags & SHF_ALLOC)) continue; if (shdr->sh_entsize & INIT_OFFSET_MASK) dest = mod->init_layout.base + (shdr->sh_entsize & ~INIT_OFFSET_MASK); else dest = mod->core_layout.base + shdr->sh_entsize; if (shdr->sh_type != SHT_NOBITS) memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size); /* Update sh_addr to point to copy in image. */ shdr->sh_addr = (unsigned long)dest; pr_debug("\t0x%lx %s\n", (long)shdr->sh_addr, info->secstrings + shdr->sh_name); } return 0; } static int check_module_license_and_versions(struct module *mod) { int prev_taint = test_taint(TAINT_PROPRIETARY_MODULE); /* * ndiswrapper is under GPL by itself, but loads proprietary modules. * Don't use add_taint_module(), as it would prevent ndiswrapper from * using GPL-only symbols it needs. */ if (strcmp(mod->name, "ndiswrapper") == 0) add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE); /* driverloader was caught wrongly pretending to be under GPL */ if (strcmp(mod->name, "driverloader") == 0) add_taint_module(mod, TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE); /* lve claims to be GPL but upstream won't provide source */ if (strcmp(mod->name, "lve") == 0) add_taint_module(mod, TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE); if (!prev_taint && test_taint(TAINT_PROPRIETARY_MODULE)) pr_warn("%s: module license taints kernel.\n", mod->name); #ifdef CONFIG_MODVERSIONS if ((mod->num_syms && !mod->crcs) || (mod->num_gpl_syms && !mod->gpl_crcs) || (mod->num_gpl_future_syms && !mod->gpl_future_crcs) #ifdef CONFIG_UNUSED_SYMBOLS || (mod->num_unused_syms && !mod->unused_crcs) || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs) #endif ) { return try_to_force_load(mod, "no versions for exported symbols"); } #endif return 0; } static void flush_module_icache(const struct module *mod) { /* * Flush the instruction cache, since we've played with text. * Do it before processing of module parameters, so the module * can provide parameter accessor functions of its own. */ if (mod->init_layout.base) flush_icache_range((unsigned long)mod->init_layout.base, (unsigned long)mod->init_layout.base + mod->init_layout.size); flush_icache_range((unsigned long)mod->core_layout.base, (unsigned long)mod->core_layout.base + mod->core_layout.size); } int __weak module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, char *secstrings, struct module *mod) { return 0; } /* module_blacklist is a comma-separated list of module names */ static char *module_blacklist; static bool blacklisted(const char *module_name) { const char *p; size_t len; if (!module_blacklist) return false; for (p = module_blacklist; *p; p += len) { len = strcspn(p, ","); if (strlen(module_name) == len && !memcmp(module_name, p, len)) return true; if (p[len] == ',') len++; } return false; } core_param(module_blacklist, module_blacklist, charp, 0400); static struct module *layout_and_allocate(struct load_info *info, int flags) { struct module *mod; unsigned int ndx; int err; err = check_modinfo(info->mod, info, flags); if (err) return ERR_PTR(err); /* Allow arches to frob section contents and sizes. */ err = module_frob_arch_sections(info->hdr, info->sechdrs, info->secstrings, info->mod); if (err < 0) return ERR_PTR(err); err = module_enforce_rwx_sections(info->hdr, info->sechdrs, info->secstrings, info->mod); if (err < 0) return ERR_PTR(err); /* We will do a special allocation for per-cpu sections later. */ info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC; /* * Mark ro_after_init section with SHF_RO_AFTER_INIT so that * layout_sections() can put it in the right place. * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set. */ ndx = find_sec(info, ".data..ro_after_init"); if (ndx) info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT; /* * Mark the __jump_table section as ro_after_init as well: these data * structures are never modified, with the exception of entries that * refer to code in the __init section, which are annotated as such * at module load time. */ ndx = find_sec(info, "__jump_table"); if (ndx) info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT; /* Determine total sizes, and put offsets in sh_entsize. For now this is done generically; there doesn't appear to be any special cases for the architectures. */ layout_sections(info->mod, info); layout_symtab(info->mod, info); /* Allocate and move to the final place */ err = move_module(info->mod, info); if (err) return ERR_PTR(err); /* Module has been copied to its final place now: return it. */ mod = (void *)info->sechdrs[info->index.mod].sh_addr; kmemleak_load_module(mod, info); return mod; } /* mod is no longer valid after this! */ static void module_deallocate(struct module *mod, struct load_info *info) { percpu_modfree(mod); module_arch_freeing_init(mod); module_memfree(mod->init_layout.base); module_memfree(mod->core_layout.base); } int __weak module_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, struct module *me) { return 0; } static int post_relocation(struct module *mod, const struct load_info *info) { /* Sort exception table now relocations are done. */ sort_extable(mod->extable, mod->extable + mod->num_exentries); /* Copy relocated percpu area over. */ percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr, info->sechdrs[info->index.pcpu].sh_size); /* Setup kallsyms-specific fields. */ add_kallsyms(mod, info); /* Arch-specific module finalizing. */ return module_finalize(info->hdr, info->sechdrs, mod); } /* Is this module of this name done loading? No locks held. */ static bool finished_loading(const char *name) { struct module *mod; bool ret; /* * The module_mutex should not be a heavily contended lock; * if we get the occasional sleep here, we'll go an extra iteration * in the wait_event_interruptible(), which is harmless. */ sched_annotate_sleep(); mutex_lock(&module_mutex); mod = find_module_all(name, strlen(name), true); ret = !mod || mod->state == MODULE_STATE_LIVE; mutex_unlock(&module_mutex); return ret; } /* Call module constructors. */ static void do_mod_ctors(struct module *mod) { #ifdef CONFIG_CONSTRUCTORS unsigned long i; for (i = 0; i < mod->num_ctors; i++) mod->ctors[i](); #endif } /* For freeing module_init on success, in case kallsyms traversing */ struct mod_initfree { struct llist_node node; void *module_init; }; static void do_free_init(struct work_struct *w) { struct llist_node *pos, *n, *list; struct mod_initfree *initfree; list = llist_del_all(&init_free_list); synchronize_rcu(); llist_for_each_safe(pos, n, list) { initfree = container_of(pos, struct mod_initfree, node); module_memfree(initfree->module_init); kfree(initfree); } } static int __init modules_wq_init(void) { INIT_WORK(&init_free_wq, do_free_init); init_llist_head(&init_free_list); return 0; } module_init(modules_wq_init); /* * This is where the real work happens. * * Keep it uninlined to provide a reliable breakpoint target, e.g. for the gdb * helper command 'lx-symbols'. */ static noinline int do_init_module(struct module *mod) { int ret = 0; struct mod_initfree *freeinit; freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL); if (!freeinit) { ret = -ENOMEM; goto fail; } freeinit->module_init = mod->init_layout.base; /* * We want to find out whether @mod uses async during init. Clear * PF_USED_ASYNC. async_schedule*() will set it. */ current->flags &= ~PF_USED_ASYNC; do_mod_ctors(mod); /* Start the module */ if (mod->init != NULL) ret = do_one_initcall(mod->init); if (ret < 0) { goto fail_free_freeinit; } if (ret > 0) { pr_warn("%s: '%s'->init suspiciously returned %d, it should " "follow 0/-E convention\n" "%s: loading module anyway...\n", __func__, mod->name, ret, __func__); dump_stack(); } /* Now it's a first class citizen! */ mod->state = MODULE_STATE_LIVE; blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_LIVE, mod); /* * We need to finish all async code before the module init sequence * is done. This has potential to deadlock. For example, a newly * detected block device can trigger request_module() of the * default iosched from async probing task. Once userland helper * reaches here, async_synchronize_full() will wait on the async * task waiting on request_module() and deadlock. * * This deadlock is avoided by perfomring async_synchronize_full() * iff module init queued any async jobs. This isn't a full * solution as it will deadlock the same if module loading from * async jobs nests more than once; however, due to the various * constraints, this hack seems to be the best option for now. * Please refer to the following thread for details. * * http://thread.gmane.org/gmane.linux.kernel/1420814 */ if (!mod->async_probe_requested && (current->flags & PF_USED_ASYNC)) async_synchronize_full(); ftrace_free_mem(mod, mod->init_layout.base, mod->init_layout.base + mod->init_layout.size); mutex_lock(&module_mutex); /* Drop initial reference. */ module_put(mod); trim_init_extable(mod); #ifdef CONFIG_KALLSYMS /* Switch to core kallsyms now init is done: kallsyms may be walking! */ rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms); #endif module_enable_ro(mod, true); mod_tree_remove_init(mod); module_arch_freeing_init(mod); mod->init_layout.base = NULL; mod->init_layout.size = 0; mod->init_layout.ro_size = 0; mod->init_layout.ro_after_init_size = 0; mod->init_layout.text_size = 0; /* * We want to free module_init, but be aware that kallsyms may be * walking this with preempt disabled. In all the failure paths, we * call synchronize_rcu(), but we don't want to slow down the success * path. module_memfree() cannot be called in an interrupt, so do the * work and call synchronize_rcu() in a work queue. * * Note that module_alloc() on most architectures creates W+X page * mappings which won't be cleaned up until do_free_init() runs. Any * code such as mark_rodata_ro() which depends on those mappings to * be cleaned up needs to sync with the queued work - ie * rcu_barrier() */ if (llist_add(&freeinit->node, &init_free_list)) schedule_work(&init_free_wq); mutex_unlock(&module_mutex); wake_up_all(&module_wq); return 0; fail_free_freeinit: kfree(freeinit); fail: /* Try to protect us from buggy refcounters. */ mod->state = MODULE_STATE_GOING; synchronize_rcu(); module_put(mod); blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_GOING, mod); klp_module_going(mod); ftrace_release_mod(mod); free_module(mod); wake_up_all(&module_wq); return ret; } static int may_init_module(void) { if (!capable(CAP_SYS_MODULE) || modules_disabled) return -EPERM; return 0; } /* * We try to place it in the list now to make sure it's unique before * we dedicate too many resources. In particular, temporary percpu * memory exhaustion. */ static int add_unformed_module(struct module *mod) { int err; struct module *old; mod->state = MODULE_STATE_UNFORMED; again: mutex_lock(&module_mutex); old = find_module_all(mod->name, strlen(mod->name), true); if (old != NULL) { if (old->state != MODULE_STATE_LIVE) { /* Wait in case it fails to load. */ mutex_unlock(&module_mutex); err = wait_event_interruptible(module_wq, finished_loading(mod->name)); if (err) goto out_unlocked; goto again; } err = -EEXIST; goto out; } mod_update_bounds(mod); list_add_rcu(&mod->list, &modules); mod_tree_insert(mod); err = 0; out: mutex_unlock(&module_mutex); out_unlocked: return err; } static int complete_formation(struct module *mod, struct load_info *info) { int err; mutex_lock(&module_mutex); /* Find duplicate symbols (must be called under lock). */ err = verify_exported_symbols(mod); if (err < 0) goto out; /* This relies on module_mutex for list integrity. */ module_bug_finalize(info->hdr, info->sechdrs, mod); module_enable_ro(mod, false); module_enable_nx(mod); module_enable_x(mod); /* Mark state as coming so strong_try_module_get() ignores us, * but kallsyms etc. can see us. */ mod->state = MODULE_STATE_COMING; mutex_unlock(&module_mutex); return 0; out: mutex_unlock(&module_mutex); return err; } static int prepare_coming_module(struct module *mod) { int err; ftrace_module_enable(mod); err = klp_module_coming(mod); if (err) return err; blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_COMING, mod); return 0; } static int unknown_module_param_cb(char *param, char *val, const char *modname, void *arg) { struct module *mod = arg; int ret; if (strcmp(param, "async_probe") == 0) { mod->async_probe_requested = true; return 0; } /* Check for magic 'dyndbg' arg */ ret = ddebug_dyndbg_module_param_cb(param, val, modname); if (ret != 0) pr_warn("%s: unknown parameter '%s' ignored\n", modname, param); return 0; } /* Allocate and load the module: note that size of section 0 is always zero, and we rely on this for optional sections. */ static int load_module(struct load_info *info, const char __user *uargs, int flags) { struct module *mod; long err = 0; char *after_dashes; err = elf_header_check(info); if (err) goto free_copy; err = setup_load_info(info, flags); if (err) goto free_copy; if (blacklisted(info->name)) { err = -EPERM; goto free_copy; } err = module_sig_check(info, flags); if (err) goto free_copy; err = rewrite_section_headers(info, flags); if (err) goto free_copy; /* Check module struct version now, before we try to use module. */ if (!check_modstruct_version(info, info->mod)) { err = -ENOEXEC; goto free_copy; } /* Figure out module layout, and allocate all the memory. */ mod = layout_and_allocate(info, flags); if (IS_ERR(mod)) { err = PTR_ERR(mod); goto free_copy; } audit_log_kern_module(mod->name); /* Reserve our place in the list. */ err = add_unformed_module(mod); if (err) goto free_module; #ifdef CONFIG_MODULE_SIG mod->sig_ok = info->sig_ok; if (!mod->sig_ok) { pr_notice_once("%s: module verification failed: signature " "and/or required key missing - tainting " "kernel\n", mod->name); add_taint_module(mod, TAINT_UNSIGNED_MODULE, LOCKDEP_STILL_OK); } #endif /* To avoid stressing percpu allocator, do this once we're unique. */ err = percpu_modalloc(mod, info); if (err) goto unlink_mod; /* Now module is in final location, initialize linked lists, etc. */ err = module_unload_init(mod); if (err) goto unlink_mod; init_param_lock(mod); /* Now we've got everything in the final locations, we can * find optional sections. */ err = find_module_sections(mod, info); if (err) goto free_unload; err = check_module_license_and_versions(mod); if (err) goto free_unload; /* Set up MODINFO_ATTR fields */ setup_modinfo(mod, info); /* Fix up syms, so that st_value is a pointer to location. */ err = simplify_symbols(mod, info); if (err < 0) goto free_modinfo; err = apply_relocations(mod, info); if (err < 0) goto free_modinfo; err = post_relocation(mod, info); if (err < 0) goto free_modinfo; flush_module_icache(mod); /* Now copy in args */ mod->args = strndup_user(uargs, ~0UL >> 1); if (IS_ERR(mod->args)) { err = PTR_ERR(mod->args); goto free_arch_cleanup; } dynamic_debug_setup(mod, info->debug, info->num_debug); /* Ftrace init must be called in the MODULE_STATE_UNFORMED state */ ftrace_module_init(mod); /* Finally it's fully formed, ready to start executing. */ err = complete_formation(mod, info); if (err) goto ddebug_cleanup; err = prepare_coming_module(mod); if (err) goto bug_cleanup; /* Module is ready to execute: parsing args may do that. */ after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp, -32768, 32767, mod, unknown_module_param_cb); if (IS_ERR(after_dashes)) { err = PTR_ERR(after_dashes); goto coming_cleanup; } else if (after_dashes) { pr_warn("%s: parameters '%s' after `--' ignored\n", mod->name, after_dashes); } /* Link in to sysfs. */ err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp); if (err < 0) goto coming_cleanup; if (is_livepatch_module(mod)) { err = copy_module_elf(mod, info); if (err < 0) goto sysfs_cleanup; } /* Get rid of temporary copy. */ free_copy(info); /* Done! */ trace_module_load(mod); return do_init_module(mod); sysfs_cleanup: mod_sysfs_teardown(mod); coming_cleanup: mod->state = MODULE_STATE_GOING; destroy_params(mod->kp, mod->num_kp); blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_GOING, mod); klp_module_going(mod); bug_cleanup: /* module_bug_cleanup needs module_mutex protection */ mutex_lock(&module_mutex); module_bug_cleanup(mod); mutex_unlock(&module_mutex); ddebug_cleanup: ftrace_release_mod(mod); dynamic_debug_remove(mod, info->debug); synchronize_rcu(); kfree(mod->args); free_arch_cleanup: module_arch_cleanup(mod); free_modinfo: free_modinfo(mod); free_unload: module_unload_free(mod); unlink_mod: mutex_lock(&module_mutex); /* Unlink carefully: kallsyms could be walking list. */ list_del_rcu(&mod->list); mod_tree_remove(mod); wake_up_all(&module_wq); /* Wait for RCU-sched synchronizing before releasing mod->list. */ synchronize_rcu(); mutex_unlock(&module_mutex); free_module: /* Free lock-classes; relies on the preceding sync_rcu() */ lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size); module_deallocate(mod, info); free_copy: free_copy(info); return err; } SYSCALL_DEFINE3(init_module, void __user *, umod, unsigned long, len, const char __user *, uargs) { int err; struct load_info info = { }; err = may_init_module(); if (err) return err; pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n", umod, len, uargs); err = copy_module_from_user(umod, len, &info); if (err) return err; return load_module(&info, uargs, 0); } SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) { struct load_info info = { }; void *hdr = NULL; int err; err = may_init_module(); if (err) return err; pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags); if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS |MODULE_INIT_IGNORE_VERMAGIC)) return -EINVAL; err = kernel_read_file_from_fd(fd, 0, &hdr, INT_MAX, NULL, READING_MODULE); if (err < 0) return err; info.hdr = hdr; info.len = err; return load_module(&info, uargs, flags); } static inline int within(unsigned long addr, void *start, unsigned long size) { return ((void *)addr >= start && (void *)addr < start + size); } #ifdef CONFIG_KALLSYMS /* * This ignores the intensely annoying "mapping symbols" found * in ARM ELF files: $a, $t and $d. */ static inline int is_arm_mapping_symbol(const char *str) { if (str[0] == '.' && str[1] == 'L') return true; return str[0] == '$' && strchr("axtd", str[1]) && (str[2] == '\0' || str[2] == '.'); } static const char *kallsyms_symbol_name(struct mod_kallsyms *kallsyms, unsigned int symnum) { return kallsyms->strtab + kallsyms->symtab[symnum].st_name; } /* * Given a module and address, find the corresponding symbol and return its name * while providing its size and offset if needed. */ static const char *find_kallsyms_symbol(struct module *mod, unsigned long addr, unsigned long *size, unsigned long *offset) { unsigned int i, best = 0; unsigned long nextval, bestval; struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms); /* At worse, next value is at end of module */ if (within_module_init(addr, mod)) nextval = (unsigned long)mod->init_layout.base+mod->init_layout.text_size; else nextval = (unsigned long)mod->core_layout.base+mod->core_layout.text_size; bestval = kallsyms_symbol_value(&kallsyms->symtab[best]); /* Scan for closest preceding symbol, and next symbol. (ELF starts real symbols at 1). */ for (i = 1; i < kallsyms->num_symtab; i++) { const Elf_Sym *sym = &kallsyms->symtab[i]; unsigned long thisval = kallsyms_symbol_value(sym); if (sym->st_shndx == SHN_UNDEF) continue; /* We ignore unnamed symbols: they're uninformative * and inserted at a whim. */ if (*kallsyms_symbol_name(kallsyms, i) == '\0' || is_arm_mapping_symbol(kallsyms_symbol_name(kallsyms, i))) continue; if (thisval <= addr && thisval > bestval) { best = i; bestval = thisval; } if (thisval > addr && thisval < nextval) nextval = thisval; } if (!best) return NULL; if (size) *size = nextval - bestval; if (offset) *offset = addr - bestval; return kallsyms_symbol_name(kallsyms, best); } void * __weak dereference_module_function_descriptor(struct module *mod, void *ptr) { return ptr; } /* For kallsyms to ask for address resolution. NULL means not found. Careful * not to lock to avoid deadlock on oopses, simply disable preemption. */ const char *module_address_lookup(unsigned long addr, unsigned long *size, unsigned long *offset, char **modname, char *namebuf) { const char *ret = NULL; struct module *mod; preempt_disable(); mod = __module_address(addr); if (mod) { if (modname) *modname = mod->name; ret = find_kallsyms_symbol(mod, addr, size, offset); } /* Make a copy in here where it's safe */ if (ret) { strncpy(namebuf, ret, KSYM_NAME_LEN - 1); ret = namebuf; } preempt_enable(); return ret; } int lookup_module_symbol_name(unsigned long addr, char *symname) { struct module *mod; preempt_disable(); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; if (within_module(addr, mod)) { const char *sym; sym = find_kallsyms_symbol(mod, addr, NULL, NULL); if (!sym) goto out; strlcpy(symname, sym, KSYM_NAME_LEN); preempt_enable(); return 0; } } out: preempt_enable(); return -ERANGE; } int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name) { struct module *mod; preempt_disable(); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; if (within_module(addr, mod)) { const char *sym; sym = find_kallsyms_symbol(mod, addr, size, offset); if (!sym) goto out; if (modname) strlcpy(modname, mod->name, MODULE_NAME_LEN); if (name) strlcpy(name, sym, KSYM_NAME_LEN); preempt_enable(); return 0; } } out: preempt_enable(); return -ERANGE; } int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type, char *name, char *module_name, int *exported) { struct module *mod; preempt_disable(); list_for_each_entry_rcu(mod, &modules, list) { struct mod_kallsyms *kallsyms; if (mod->state == MODULE_STATE_UNFORMED) continue; kallsyms = rcu_dereference_sched(mod->kallsyms); if (symnum < kallsyms->num_symtab) { const Elf_Sym *sym = &kallsyms->symtab[symnum]; *value = kallsyms_symbol_value(sym); *type = kallsyms->typetab[symnum]; strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN); strlcpy(module_name, mod->name, MODULE_NAME_LEN); *exported = is_exported(name, *value, mod); preempt_enable(); return 0; } symnum -= kallsyms->num_symtab; } preempt_enable(); return -ERANGE; } /* Given a module and name of symbol, find and return the symbol's value */ static unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name) { unsigned int i; struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms); for (i = 0; i < kallsyms->num_symtab; i++) { const Elf_Sym *sym = &kallsyms->symtab[i]; if (strcmp(name, kallsyms_symbol_name(kallsyms, i)) == 0 && sym->st_shndx != SHN_UNDEF) return kallsyms_symbol_value(sym); } return 0; } /* Look for this name: can be of form module:name. */ unsigned long module_kallsyms_lookup_name(const char *name) { struct module *mod; char *colon; unsigned long ret = 0; /* Don't lock: we're in enough trouble already. */ preempt_disable(); if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) { if ((mod = find_module_all(name, colon - name, false)) != NULL) ret = find_kallsyms_symbol_value(mod, colon+1); } else { list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; if ((ret = find_kallsyms_symbol_value(mod, name)) != 0) break; } } preempt_enable(); return ret; } int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, unsigned long), void *data) { struct module *mod; unsigned int i; int ret; module_assert_mutex(); list_for_each_entry(mod, &modules, list) { /* We hold module_mutex: no need for rcu_dereference_sched */ struct mod_kallsyms *kallsyms = mod->kallsyms; if (mod->state == MODULE_STATE_UNFORMED) continue; for (i = 0; i < kallsyms->num_symtab; i++) { const Elf_Sym *sym = &kallsyms->symtab[i]; if (sym->st_shndx == SHN_UNDEF) continue; ret = fn(data, kallsyms_symbol_name(kallsyms, i), mod, kallsyms_symbol_value(sym)); if (ret != 0) return ret; } } return 0; } #endif /* CONFIG_KALLSYMS */ /* Maximum number of characters written by module_flags() */ #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4) /* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */ static char *module_flags(struct module *mod, char *buf) { int bx = 0; BUG_ON(mod->state == MODULE_STATE_UNFORMED); if (mod->taints || mod->state == MODULE_STATE_GOING || mod->state == MODULE_STATE_COMING) { buf[bx++] = '('; bx += module_flags_taint(mod, buf + bx); /* Show a - for module-is-being-unloaded */ if (mod->state == MODULE_STATE_GOING) buf[bx++] = '-'; /* Show a + for module-is-being-loaded */ if (mod->state == MODULE_STATE_COMING) buf[bx++] = '+'; buf[bx++] = ')'; } buf[bx] = '\0'; return buf; } #ifdef CONFIG_PROC_FS /* Called by the /proc file system to return a list of modules. */ static void *m_start(struct seq_file *m, loff_t *pos) { mutex_lock(&module_mutex); return seq_list_start(&modules, *pos); } static void *m_next(struct seq_file *m, void *p, loff_t *pos) { return seq_list_next(p, &modules, pos); } static void m_stop(struct seq_file *m, void *p) { mutex_unlock(&module_mutex); } static int m_show(struct seq_file *m, void *p) { struct module *mod = list_entry(p, struct module, list); char buf[MODULE_FLAGS_BUF_SIZE]; void *value; /* We always ignore unformed modules. */ if (mod->state == MODULE_STATE_UNFORMED) return 0; seq_printf(m, "%s %u", mod->name, mod->init_layout.size + mod->core_layout.size); print_unload_info(m, mod); /* Informative for users. */ seq_printf(m, " %s", mod->state == MODULE_STATE_GOING ? "Unloading" : mod->state == MODULE_STATE_COMING ? "Loading" : "Live"); /* Used by oprofile and other similar tools. */ value = m->private ? NULL : mod->core_layout.base; seq_printf(m, " 0x%px", value); /* Taints info */ if (mod->taints) seq_printf(m, " %s", module_flags(mod, buf)); seq_puts(m, "\n"); return 0; } /* Format: modulename size refcount deps address Where refcount is a number or -, and deps is a comma-separated list of depends or -. */ static const struct seq_operations modules_op = { .start = m_start, .next = m_next, .stop = m_stop, .show = m_show }; /* * This also sets the "private" pointer to non-NULL if the * kernel pointers should be hidden (so you can just test * "m->private" to see if you should keep the values private). * * We use the same logic as for /proc/kallsyms. */ static int modules_open(struct inode *inode, struct file *file) { int err = seq_open(file, &modules_op); if (!err) { struct seq_file *m = file->private_data; m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul; } return err; } static const struct proc_ops modules_proc_ops = { .proc_flags = PROC_ENTRY_PERMANENT, .proc_open = modules_open, .proc_read = seq_read, .proc_lseek = seq_lseek, .proc_release = seq_release, }; static int __init proc_modules_init(void) { proc_create("modules", 0, NULL, &modules_proc_ops); return 0; } module_init(proc_modules_init); #endif /* Given an address, look for it in the module exception tables. */ const struct exception_table_entry *search_module_extables(unsigned long addr) { const struct exception_table_entry *e = NULL; struct module *mod; preempt_disable(); mod = __module_address(addr); if (!mod) goto out; if (!mod->num_exentries) goto out; e = search_extable(mod->extable, mod->num_exentries, addr); out: preempt_enable(); /* * Now, if we found one, we are running inside it now, hence * we cannot unload the module, hence no refcnt needed. */ return e; } /* * is_module_address - is this address inside a module? * @addr: the address to check. * * See is_module_text_address() if you simply want to see if the address * is code (not data). */ bool is_module_address(unsigned long addr) { bool ret; preempt_disable(); ret = __module_address(addr) != NULL; preempt_enable(); return ret; } /* * __module_address - get the module which contains an address. * @addr: the address. * * Must be called with preempt disabled or module mutex held so that * module doesn't get freed during this. */ struct module *__module_address(unsigned long addr) { struct module *mod; if (addr < module_addr_min || addr > module_addr_max) return NULL; module_assert_mutex_or_preempt(); mod = mod_find(addr); if (mod) { BUG_ON(!within_module(addr, mod)); if (mod->state == MODULE_STATE_UNFORMED) mod = NULL; } return mod; } /* * is_module_text_address - is this address inside module code? * @addr: the address to check. * * See is_module_address() if you simply want to see if the address is * anywhere in a module. See kernel_text_address() for testing if an * address corresponds to kernel or module code. */ bool is_module_text_address(unsigned long addr) { bool ret; preempt_disable(); ret = __module_text_address(addr) != NULL; preempt_enable(); return ret; } /* * __module_text_address - get the module whose code contains an address. * @addr: the address. * * Must be called with preempt disabled or module mutex held so that * module doesn't get freed during this. */ struct module *__module_text_address(unsigned long addr) { struct module *mod = __module_address(addr); if (mod) { /* Make sure it's within the text section. */ if (!within(addr, mod->init_layout.base, mod->init_layout.text_size) && !within(addr, mod->core_layout.base, mod->core_layout.text_size)) mod = NULL; } return mod; } /* Don't grab lock, we're oopsing. */ void print_modules(void) { struct module *mod; char buf[MODULE_FLAGS_BUF_SIZE]; printk(KERN_DEFAULT "Modules linked in:"); /* Most callers should already have preempt disabled, but make sure */ preempt_disable(); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; pr_cont(" %s%s", mod->name, module_flags(mod, buf)); } preempt_enable(); if (last_unloaded_module[0]) 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