/* 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 "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_DEBUG_SET_MODULE_RONX=y */ #ifdef CONFIG_DEBUG_SET_MODULE_RONX # define debug_align(X) ALIGN(X, PAGE_SIZE) #else # define debug_align(X) (X) #endif /* * Given BASE and SIZE this macro calculates the number of pages the * memory regions occupies */ #define MOD_NUMBER_OF_PAGES(BASE, SIZE) (((SIZE) > 0) ? \ (PFN_DOWN((unsigned long)(BASE) + (SIZE) - 1) - \ PFN_DOWN((unsigned long)BASE) + 1) \ : (0UL)) /* 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 uses stop_machine/add uses RCU list operations). */ DEFINE_MUTEX(module_mutex); EXPORT_SYMBOL_GPL(module_mutex); static LIST_HEAD(modules); #ifdef CONFIG_KGDB_KDB struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */ #endif /* CONFIG_KGDB_KDB */ #ifdef CONFIG_MODULE_SIG #ifdef CONFIG_MODULE_SIG_FORCE static bool sig_enforce = true; #else static bool sig_enforce = false; static int param_set_bool_enable_only(const char *val, const struct kernel_param *kp) { int err; bool test; struct kernel_param dummy_kp = *kp; dummy_kp.arg = &test; err = param_set_bool(val, &dummy_kp); if (err) return err; /* Don't let them unset it once it's set! */ if (!test && sig_enforce) return -EROFS; if (test) sig_enforce = true; return 0; } static const struct kernel_param_ops param_ops_bool_enable_only = { .set = param_set_bool_enable_only, .get = param_get_bool, }; #define param_check_bool_enable_only param_check_bool module_param(sig_enforce, bool_enable_only, 0644); #endif /* !CONFIG_MODULE_SIG_FORCE */ #endif /* CONFIG_MODULE_SIG */ /* 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); /* Bounds of module allocation, for speeding __module_address. * Protected by module_mutex. */ static unsigned long module_addr_min = -1UL, module_addr_max = 0; 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 { 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; struct { unsigned int sym, str, mod, vers, info, pcpu; } index; }; /* We require a truly strong try_module_get(): 0 means failure 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); mod->taints |= (1U << flag); } /* * 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 __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 unsigned long __start___kcrctab[]; extern const unsigned long __start___kcrctab_gpl[]; extern const unsigned long __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 unsigned long __start___kcrctab_unused[]; extern const unsigned long __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 }; 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 unsigned long *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) { printk(KERN_WARNING "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) { printk(KERN_WARNING "Symbol %s is marked as UNUSED, " "however this module is using it.\n", fsa->name); printk(KERN_WARNING "This symbol will go away in the future.\n"); printk(KERN_WARNING "Please evalute if this is the right api to use and if " "it really is, submit a report the linux kernel " "mailinglist 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 unsigned long **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. */ static struct module *find_module_all(const char *name, bool even_unformed) { struct module *mod; list_for_each_entry(mod, &modules, list) { if (!even_unformed && mod->state == MODULE_STATE_UNFORMED) continue; if (strcmp(mod->name, name) == 0) return mod; } return NULL; } struct module *find_module(const char *name) { return find_module_all(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, unsigned long size, unsigned long align) { if (align > PAGE_SIZE) { printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n", mod->name, align, PAGE_SIZE); align = PAGE_SIZE; } mod->percpu = __alloc_reserved_percpu(size, align); if (!mod->percpu) { printk(KERN_WARNING "%s: Could not allocate %lu bytes percpu data\n", mod->name, size); return -ENOMEM; } mod->percpu_size = 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); } /** * 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) { 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); if ((void *)addr >= start && (void *)addr < start + mod->percpu_size) { preempt_enable(); return true; } } } preempt_enable(); return false; } #else /* ... !CONFIG_SMP */ static inline void __percpu *mod_percpu(struct module *mod) { return NULL; } static inline int percpu_modalloc(struct module *mod, unsigned long size, unsigned long align) { return -ENOMEM; } 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; } #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 sprintf(buffer, "%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); /* Init the unload section of the module. */ static int module_unload_init(struct module *mod) { mod->refptr = alloc_percpu(struct module_ref); if (!mod->refptr) return -ENOMEM; INIT_LIST_HEAD(&mod->source_list); INIT_LIST_HEAD(&mod->target_list); /* Hold reference count during initialization. */ __this_cpu_write(mod->refptr->incs, 1); /* Backwards compatibility macros put refcount during init. */ mod->waiter = current; 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) { printk(KERN_WARNING "%s: out of memory loading\n", a->name); 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); free_percpu(mod->refptr); } #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 */ struct stopref { struct module *mod; int flags; int *forced; }; /* Whole machine is stopped with interrupts off when this runs. */ static int __try_stop_module(void *_sref) { struct stopref *sref = _sref; /* If it's not unused, quit unless we're forcing. */ if (module_refcount(sref->mod) != 0) { if (!(*sref->forced = try_force_unload(sref->flags))) return -EWOULDBLOCK; } /* Mark it as dying. */ sref->mod->state = MODULE_STATE_GOING; return 0; } static int try_stop_module(struct module *mod, int flags, int *forced) { if (flags & O_NONBLOCK) { struct stopref sref = { mod, flags, forced }; return stop_machine(__try_stop_module, &sref, NULL); } else { /* We don't need to stop the machine for this. */ mod->state = MODULE_STATE_GOING; synchronize_sched(); return 0; } } unsigned long module_refcount(struct module *mod) { unsigned long incs = 0, decs = 0; int cpu; for_each_possible_cpu(cpu) decs += per_cpu_ptr(mod->refptr, cpu)->decs; /* * ensure the incs are added up after the decs. * module_put ensures incs are visible before decs with smp_wmb. * * This 2-count scheme avoids the situation where the refcount * for CPU0 is read, then CPU0 increments the module refcount, * then CPU1 drops that refcount, then the refcount for CPU1 is * read. We would record a decrement but not its corresponding * increment so we would see a low count (disaster). * * Rare situation? But module_refcount can be preempted, and we * might be tallying up 4096+ CPUs. So it is not impossible. */ smp_rmb(); for_each_possible_cpu(cpu) incs += per_cpu_ptr(mod->refptr, cpu)->incs; return incs - decs; } EXPORT_SYMBOL(module_refcount); /* This exists whether we can unload or not */ static void free_module(struct module *mod); static void wait_for_zero_refcount(struct module *mod) { /* Since we might sleep for some time, release the mutex first */ mutex_unlock(&module_mutex); for (;;) { pr_debug("Looking at refcount...\n"); set_current_state(TASK_UNINTERRUPTIBLE); if (module_refcount(mod) == 0) break; schedule(); } current->state = TASK_RUNNING; mutex_lock(&module_mutex); } 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'; 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 and wake up waiter --RR */ 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; } } /* Set this up before setting mod->state */ mod->waiter = current; /* Stop the machine so refcounts can't move and disable module. */ ret = try_stop_module(mod, flags, &forced); if (ret != 0) goto out; /* Never wait if forced. */ if (!forced && module_refcount(mod) != 0) wait_for_zero_refcount(mod); 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); 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, " %lu ", 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_printf(m, "[permanent],"); } if (!printed_something) seq_printf(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; /* module_text_address is safe here: we're supposed to have reference * to module from symbol_get, so it can't go away. */ modaddr = __module_text_address(a); BUG_ON(!modaddr); module_put(modaddr); } EXPORT_SYMBOL_GPL(symbol_put_addr); static ssize_t show_refcnt(struct module_attribute *mattr, struct module_kobject *mk, char *buffer) { return sprintf(buffer, "%lu\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(); __this_cpu_inc(module->refptr->incs); 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(); if (likely(module_is_live(module))) { __this_cpu_inc(module->refptr->incs); trace_module_get(module, _RET_IP_); } else ret = false; preempt_enable(); } return ret; } EXPORT_SYMBOL(try_module_get); void module_put(struct module *module) { if (module) { preempt_disable(); smp_wmb(); /* see comment in module_refcount */ __this_cpu_inc(module->refptr->decs); trace_module_put(module, _RET_IP_); /* Maybe they're waiting for us to drop reference? */ if (unlikely(!module_is_live(module))) wake_up_process(module->waiter); 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_printf(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; if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE)) buf[l++] = 'P'; if (mod->taints & (1 << TAINT_OOT_MODULE)) buf[l++] = 'O'; if (mod->taints & (1 << TAINT_FORCED_MODULE)) buf[l++] = 'F'; if (mod->taints & (1 << TAINT_CRAP)) buf[l++] = 'C'; /* * TAINT_FORCED_RMMOD: could be added. * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't * apply to modules. */ 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) { enum kobject_action action; if (kobject_action_type(buffer, count, &action) == 0) kobject_uevent(&mk->kobj, action); 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_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_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)) printk(KERN_WARNING "%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 /* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */ static unsigned long maybe_relocated(unsigned long crc, const struct module *crc_owner) { #ifdef ARCH_RELOCATES_KCRCTAB if (crc_owner == NULL) return crc - (unsigned long)reloc_start; #endif return crc; } static int check_version(Elf_Shdr *sechdrs, unsigned int versindex, const char *symname, struct module *mod, const unsigned long *crc, const struct module *crc_owner) { 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++) { if (strcmp(versions[i].name, symname) != 0) continue; if (versions[i].crc == maybe_relocated(*crc, crc_owner)) return 1; pr_debug("Found checksum %lX vs module %lX\n", maybe_relocated(*crc, crc_owner), versions[i].crc); goto bad_version; } printk(KERN_WARNING "%s: no symbol version for %s\n", mod->name, symname); return 0; bad_version: printk("%s: disagrees about version of symbol %s\n", mod->name, symname); return 0; } static inline int check_modstruct_version(Elf_Shdr *sechdrs, unsigned int versindex, struct module *mod) { const unsigned long *crc; /* Since this should be found in kernel (which can't be removed), * no locking is necessary. */ if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL, &crc, true, false)) BUG(); return check_version(sechdrs, versindex, "module_layout", mod, crc, NULL); } /* 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(Elf_Shdr *sechdrs, unsigned int versindex, const char *symname, struct module *mod, const unsigned long *crc, const struct module *crc_owner) { return 1; } static inline int check_modstruct_version(Elf_Shdr *sechdrs, unsigned int versindex, 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 unsigned long *crc; int err; 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->sechdrs, info->index.vers, name, mod, crc, owner)) { 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) { printk(KERN_WARNING "%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%pK\n", (void *)sattr->address); } 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_IRUGO; *(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 add_usage_links(struct module *mod) { #ifdef CONFIG_MODULE_UNLOAD struct module_use *use; int nowarn; mutex_lock(&module_mutex); list_for_each_entry(use, &mod->target_list, target_list) { nowarn = sysfs_create_link(use->target->holders_dir, &mod->mkobj.kobj, mod->name); } mutex_unlock(&module_mutex); #endif } 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 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 && 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 int mod_sysfs_init(struct module *mod) { int err; struct kobject *kobj; if (!module_sysfs_initialized) { printk(KERN_ERR "%s: module sysfs not initialized\n", mod->name); err = -EINVAL; goto out; } kobj = kset_find_obj(module_kset, mod->name); if (kobj) { printk(KERN_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) kobject_put(&mod->mkobj.kobj); /* 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; add_usage_links(mod); add_sect_attrs(mod, info); add_notes_attrs(mod, info); kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD); return 0; out_unreg_param: module_param_sysfs_remove(mod); out_unreg_holders: kobject_put(mod->holders_dir); out_unreg: kobject_put(&mod->mkobj.kobj); out: return err; } static void mod_sysfs_fini(struct module *mod) { remove_notes_attrs(mod); remove_sect_attrs(mod); kobject_put(&mod->mkobj.kobj); } #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) { } #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); } /* * unlink the module with the whole machine is stopped with interrupts off * - this defends against kallsyms not taking locks */ static int __unlink_module(void *_mod) { struct module *mod = _mod; list_del(&mod->list); module_bug_cleanup(mod); return 0; } #ifdef CONFIG_DEBUG_SET_MODULE_RONX /* * LKM RO/NX protection: protect module's text/ro-data * from modification and any data from execution. */ void set_page_attributes(void *start, void *end, int (*set)(unsigned long start, int num_pages)) { unsigned long begin_pfn = PFN_DOWN((unsigned long)start); unsigned long end_pfn = PFN_DOWN((unsigned long)end); if (end_pfn > begin_pfn) set(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn); } static void set_section_ro_nx(void *base, unsigned long text_size, unsigned long ro_size, unsigned long total_size) { /* begin and end PFNs of the current subsection */ unsigned long begin_pfn; unsigned long end_pfn; /* * Set RO for module text and RO-data: * - Always protect first page. * - Do not protect last partial page. */ if (ro_size > 0) set_page_attributes(base, base + ro_size, set_memory_ro); /* * Set NX permissions for module data: * - Do not protect first partial page. * - Always protect last page. */ if (total_size > text_size) { begin_pfn = PFN_UP((unsigned long)base + text_size); end_pfn = PFN_UP((unsigned long)base + total_size); if (end_pfn > begin_pfn) set_memory_nx(begin_pfn << PAGE_SHIFT, end_pfn - begin_pfn); } } static void unset_module_core_ro_nx(struct module *mod) { set_page_attributes(mod->module_core + mod->core_text_size, mod->module_core + mod->core_size, set_memory_x); set_page_attributes(mod->module_core, mod->module_core + mod->core_ro_size, set_memory_rw); } static void unset_module_init_ro_nx(struct module *mod) { set_page_attributes(mod->module_init + mod->init_text_size, mod->module_init + mod->init_size, set_memory_x); set_page_attributes(mod->module_init, mod->module_init + mod->init_ro_size, set_memory_rw); } /* Iterate through all modules and set each module's text as RW */ void set_all_modules_text_rw(void) { struct module *mod; mutex_lock(&module_mutex); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; if ((mod->module_core) && (mod->core_text_size)) { set_page_attributes(mod->module_core, mod->module_core + mod->core_text_size, set_memory_rw); } if ((mod->module_init) && (mod->init_text_size)) { set_page_attributes(mod->module_init, mod->module_init + mod->init_text_size, 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; mutex_lock(&module_mutex); list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; if ((mod->module_core) && (mod->core_text_size)) { set_page_attributes(mod->module_core, mod->module_core + mod->core_text_size, set_memory_ro); } if ((mod->module_init) && (mod->init_text_size)) { set_page_attributes(mod->module_init, mod->module_init + mod->init_text_size, set_memory_ro); } } mutex_unlock(&module_mutex); } #else static inline void set_section_ro_nx(void *base, unsigned long text_size, unsigned long ro_size, unsigned long total_size) { } static void unset_module_core_ro_nx(struct module *mod) { } static void unset_module_init_ro_nx(struct module *mod) { } #endif void __weak module_free(struct module *mod, void *module_region) { vfree(module_region); } void __weak module_arch_cleanup(struct module *mod) { } /* Free a module, remove from lists, etc. */ static void free_module(struct module *mod) { trace_module_free(mod); /* Delete from various lists */ mutex_lock(&module_mutex); stop_machine(__unlink_module, mod, NULL); mutex_unlock(&module_mutex); mod_sysfs_teardown(mod); /* 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); /* This may be NULL, but that's OK */ unset_module_init_ro_nx(mod); module_free(mod, mod->module_init); kfree(mod->args); percpu_modfree(mod); /* Free lock-classes: */ lockdep_free_key_range(mod->module_core, mod->core_size); /* Finally, free the core (containing the module structure) */ unset_module_core_ro_nx(mod); module_free(mod, mod->module_core); #ifdef CONFIG_MPU update_protections(current->mm); #endif } 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)) { printk(KERN_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: /* We compiled with -fno-common. These are not supposed to happen. */ pr_debug("Common symbol: %s\n", name); printk("%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_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; printk(KERN_WARNING "%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; 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_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_size, s, i); pr_debug("\t%s\n", sname); } switch (m) { case 0: /* executable */ mod->core_size = debug_align(mod->core_size); mod->core_text_size = mod->core_size; break; case 1: /* RO: text and ro-data */ mod->core_size = debug_align(mod->core_size); mod->core_ro_size = mod->core_size; break; case 3: /* whole core */ mod->core_size = debug_align(mod->core_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_size, s, i) | INIT_OFFSET_MASK); pr_debug("\t%s\n", sname); } switch (m) { case 0: /* executable */ mod->init_size = debug_align(mod->init_size); mod->init_text_size = mod->init_size; break; case 1: /* RO: text and ro-data */ mod->init_size = debug_align(mod->init_size); mod->init_ro_size = mod->init_size; break; case 3: /* whole init */ mod->init_size = debug_align(mod->init_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)) printk(KERN_WARNING "%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 == 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) 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) { const Elf_Shdr *sec; if (src->st_shndx == SHN_UNDEF || src->st_shndx >= shnum || !src->st_name) return false; 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_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_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) { 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_size, symsect->sh_addralign ?: 1); info->stroffs = mod->core_size = info->symoffs + ndst * sizeof(Elf_Sym); mod->core_size += strtab_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_size, strsect, info->index.str) | INIT_OFFSET_MASK; pr_debug("\t%s\n", info->secstrings + strsect->sh_name); } 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]; mod->symtab = (void *)symsec->sh_addr; mod->num_symtab = symsec->sh_size / sizeof(Elf_Sym); /* Make sure we get permanent strtab: don't use info->strtab. */ mod->strtab = (void *)info->sechdrs[info->index.str].sh_addr; /* Set types up while we still have access to sections. */ for (i = 0; i < mod->num_symtab; i++) mod->symtab[i].st_info = elf_type(&mod->symtab[i], info); mod->core_symtab = dst = mod->module_core + info->symoffs; mod->core_strtab = s = mod->module_core + info->stroffs; src = mod->symtab; for (ndst = i = 0; i < mod->num_symtab; i++) { if (i == 0 || is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) { dst[ndst] = src[i]; dst[ndst++].st_name = s - mod->core_strtab; s += strlcpy(s, &mod->strtab[src[i].st_name], KSYM_NAME_LEN) + 1; } } mod->core_num_syms = 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 _ddebug *debug, unsigned int num) { if (!debug) return; #ifdef CONFIG_DYNAMIC_DEBUG if (ddebug_add_module(debug, num, debug->modname)) printk(KERN_ERR "dynamic debug error adding module: %s\n", debug->modname); #endif } static void dynamic_debug_remove(struct _ddebug *debug) { if (debug) ddebug_remove_module(debug->modname); } void * __weak module_alloc(unsigned long size) { return vmalloc_exec(size); } static void *module_alloc_update_bounds(unsigned long size) { void *ret = module_alloc(size); if (ret) { mutex_lock(&module_mutex); /* Update module bounds. */ if ((unsigned long)ret < module_addr_min) module_addr_min = (unsigned long)ret; if ((unsigned long)ret + size > module_addr_max) module_addr_max = (unsigned long)ret + size; mutex_unlock(&module_mutex); } return ret; } #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++) { const char *name = info->secstrings + info->sechdrs[i].sh_name; if (!(info->sechdrs[i].sh_flags & SHF_ALLOC)) continue; if (!strstarts(name, ".data") && !strstarts(name, ".bss")) 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 err = -ENOKEY; const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; const void *mod = info->hdr; if (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->len); } if (!err) { info->sig_ok = true; return 0; } /* Not having a signature is only an error if we're strict. */ if (err < 0 && fips_enabled) panic("Module verification failed with error %d in FIPS mode\n", err); if (err == -ENOKEY && !sig_enforce) err = 0; return err; } #else /* !CONFIG_MODULE_SIG */ static int module_sig_check(struct load_info *info) { 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; } /* 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_module_from_file(NULL); if (err) return err; /* Suck in entire file: we'll want most of it. */ info->hdr = vmalloc(info->len); if (!info->hdr) return -ENOMEM; if (copy_from_user(info->hdr, umod, info->len) != 0) { vfree(info->hdr); return -EFAULT; } return 0; } /* Sets info->hdr and info->len. */ static int copy_module_from_fd(int fd, struct load_info *info) { struct file *file; int err; struct kstat stat; loff_t pos; ssize_t bytes = 0; file = fget(fd); if (!file) return -ENOEXEC; err = security_kernel_mo