/* Copyright (C) 2002 Richard Henderson Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #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_STRICT_MODULE_RWX=y */ #ifdef CONFIG_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); #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) { 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); #ifndef CONFIG_MODULE_SIG_FORCE module_param(sig_enforce, bool_enable_only, 0644); #endif /* !CONFIG_MODULE_SIG_FORCE */ /* * 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); /* 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); struct load_info { const char *name; Elf_Ehdr *hdr; unsigned long len; Elf_Shdr *sechdrs; char *secstrings, *strtab; unsigned long symoffs, stroffs; struct _ddebug *debug; unsigned int num_debug; bool sig_ok; #ifdef CONFIG_KALLSYMS unsigned long mod_kallsyms_init_off; #endif struct { unsigned int sym, str, mod, vers, info, pcpu; } index; }; /* * 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. */ 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) { 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; } EXPORT_SYMBOL_GPL(each_symbol_section); struct find_symbol_arg { /* Input */ const char *name; bool gplok; bool warn; /* Output */ struct module *owner; const s32 *crc; const struct kernel_symbol *sym; }; static bool check_symbol(const struct symsearch *syms, struct module *owner, unsigned int symnum, void *data) { struct find_symbol_arg *fsa = data; if (!fsa->gplok) { if (syms->licence == GPL_ONLY) return false; if (syms->licence == 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]; return true; } static int cmp_name(const void *va, const void *vb) { const char *a; const struct kernel_symbol *b; a = va; b = vb; return strcmp(a, b->name); } static bool find_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_symbol(syms, owner, sym - syms->start, data)) return true; return false; } /* Find a symbol and return it, along with, (optional) crc and * (optional) module which owns it. Needs preempt disabled or module_mutex. */ const struct kernel_symbol *find_symbol(const char *name, struct module **owner, const s32 **crc, bool gplok, bool warn) { struct find_symbol_arg fsa; fsa.name = name; fsa.gplok = gplok; fsa.warn = warn; if (each_symbol_section(find_symbol_in_section, &fsa)) { if (owner) *owner = fsa.owner; if (crc) *crc = fsa.crc; return fsa.sym; } pr_debug("Failed to find symbol %s\n", name); return NULL; } EXPORT_SYMBOL_GPL(find_symbol); /* * 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) { 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() */ 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; } EXPORT_SYMBOL_GPL(ref_module); /* 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); 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, 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) { } int ref_module(struct module *a, struct module *b) { return strong_try_module_get(b); } EXPORT_SYMBOL_GPL(ref_module); 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) { kobject_synth_uevent(&mk->kobj, buffer, count); return 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(VMLINUX_SYMBOL_STR(module_layout), NULL, &crc, true, false)) { preempt_enable(); BUG(); } preempt_enable(); return check_version(info, VMLINUX_SYMBOL_STR(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 */ /* 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; 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, !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true); if (!sym) goto unlock; if (!check_version(info, name, mod, crc)) { sym = ERR_PTR(-EINVAL); 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 module_attribute mattr; char *name; unsigned long address; }; struct module_sect_attrs { struct attribute_group grp; unsigned int nsections; struct module_sect_attr attrs[0]; }; static ssize_t module_sect_show(struct module_attribute *mattr, struct module_kobject *mk, char *buf) { struct module_sect_attr *sattr = container_of(mattr, struct module_sect_attr, mattr); return sprintf(buf, "0x%px\n", kptr_restrict < 2 ? (void *)sattr->address : NULL); } 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].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 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(sizeof(*sect_attrs) + nloaded * sizeof(sect_attrs->attrs[0]), sizeof(sect_attrs->grp.attrs[0])); size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.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.attrs = (void *)sect_attrs + size[0]; sect_attrs->nsections = 0; sattr = §_attrs->attrs[0]; gattr = §_attrs->grp.attrs[0]; for (i = 0; i < info->hdr->e_shnum; i++) { Elf_Shdr *sec = &info->sechdrs[i]; if (sect_empty(sec)) continue; sattr->address = sec->sh_addr; sattr->name = kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL); if (sattr->name == NULL) goto out; sect_attrs->nsections++; sysfs_attr_init(&sattr->mattr.attr); sattr->mattr.show = module_sect_show; sattr->mattr.store = NULL; sattr->mattr.attr.name = sattr->name; sattr->mattr.attr.mode = S_IRUSR; *(gattr++) = &(sattr++)->mattr.attr; } *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[0]; }; 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(sizeof(*notes_attrs) + notes * sizeof(notes_attrs->attrs[0]), 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].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 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]) && !error; 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); ++temp_attr; } } return error; } static void module_remove_modinfo_attrs(struct module *mod) { struct module_attribute *attr; int i; for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) { /* 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); 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) { } 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); module_param_sysfs_remove(mod); kobject_put(mod->mkobj.drivers_dir); kobject_put(mod->holders_dir); mod_sysfs_fini(mod); } #ifdef CONFIG_STRICT_MODULE_RWX /* * 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) */ 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 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); } /* livepatching wants to disable read-only so it can frob module. */ void module_disable_ro(const struct module *mod) { if (!rodata_enabled) return; frob_text(&mod->core_layout, set_memory_rw); frob_rodata(&mod->core_layout, set_memory_rw); frob_ro_after_init(&mod->core_layout, set_memory_rw); frob_text(&mod->init_layout, set_memory_rw); frob_rodata(&mod->init_layout, set_memory_rw); } void module_enable_ro(const struct module *mod, bool after_init) { if (!rodata_enabled) return; 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 void module_disable_nx(const struct module *mod) { frob_rodata(&mod->core_layout, set_memory_x); frob_ro_after_init(&mod->core_layout, set_memory_x); frob_writable_data(&mod->core_layout, set_memory_x); frob_rodata(&mod->init_layout, set_memory_x); frob_writable_data(&mod->init_layout, set_memory_x); } /* Iterate through all modules and set each module's text as RW */ void set_all_modules_text_rw(void) { struct module *mod; if (!rodata_enabled) return; mutex_lock(&module_mutex); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; frob_text(&mod->core_layout, set_memory_rw); frob_text(&mod->init_layout, set_memory_rw); } mutex_unlock(&module_mutex); } /* Iterate through all modules and set each module's text as RO */ void set_all_modules_text_ro(void) { struct module *mod; if (!rodata_enabled) return; mutex_lock(&module_mutex); list_for_each_entry_rcu(mod, &modules, list) { /* * Ignore going modules since it's possible that ro * protection has already been disabled, otherwise we'll * run into protection faults at module deallocation. */ if (mod->state == MODULE_STATE_UNFORMED || mod->state == MODULE_STATE_GOING) continue; frob_text(&mod->core_layout, set_memory_ro); frob_text(&mod->init_layout, set_memory_ro); } mutex_unlock(&module_mutex); } static void disable_ro_nx(const struct module_layout *layout) { if (rodata_enabled) { frob_text(layout, set_memory_rw); frob_rodata(layout, set_memory_rw); frob_ro_after_init(layout, set_memory_rw); } frob_rodata(layout, set_memory_x); frob_ro_after_init(layout, set_memory_x); frob_writable_data(layout, set_memory_x); } #else static void disable_ro_nx(const struct module_layout *layout) { } static void module_enable_nx(const struct module *mod) { } static void module_disable_nx(const struct module *mod) { } #endif #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 = kmalloc(size, GFP_KERNEL); if (mod->klp_info->sechdrs == NULL) { ret = -ENOMEM; goto free_info; } memcpy(mod->klp_info->sechdrs, info->sechdrs, size); /* Elf section name string table */ size = info->sechdrs[info->hdr->e_shstrndx].sh_size; mod->klp_info->secstrings = kmalloc(size, GFP_KERNEL); if (mod->klp_info->secstrings == NULL) { ret = -ENOMEM; goto free_sechdrs; } memcpy(mod->klp_info->secstrings, info->secstrings, size); /* 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) { 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_sched(); mutex_unlock(&module_mutex); /* This may be empty, but that's OK */ disable_ro_nx(&mod->init_layout); 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) */ disable_ro_nx(&mod->core_layout); 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, true, true); if (sym && strong_try_module_get(owner)) sym = NULL; preempt_enable(); return sym ? (void *)sym->value : 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_export_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(s->name, &owner, NULL, true, false)) { pr_err("%s: exports duplicate symbol %s" " (owned by %s)\n", mod->name, s->name, 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 = ksym->value; break; } /* Ok if weak. */ if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK) break; pr_warn("%s: Unknown symbol %s (err %li)\n", mod->name, name, PTR_ERR(ksym)); ret = PTR_ERR(ksym) ?: -ENOENT; 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; /* Livepatch relocation sections are applied by livepatch */ if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH) continue; 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 || strstarts(sname, ".init")) 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 || !strstarts(sname, ".init")) 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_modinfo(struct load_info *info, const char *tag) { char *p; unsigned int taglen = strlen(tag); Elf_Shdr *infosec = &info->sechdrs[info->index.info]; unsigned long size = infosec->sh_size; for (p = (char *)infosec->sh_addr; p; p = next_string(p, &size)) { if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=') return p + taglen + 1; } return 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 symbol in given range of kernel_symbols */ static const struct kernel_symbol *lookup_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_symbol(name, __start___ksymtab, __stop___ksymtab); else ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms); return ks != NULL && ks->value ==