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linux/kernel/module/main.c
Linus Torvalds 2124d84db2 module: make waiting for a concurrent module loader interruptible 
The recursive aes-arm-bs module load situation reported by Russell King
is getting fixed in the crypto layer, but this in the meantime fixes the
"recursive load hangs forever" by just making the waiting for the first
module load be interruptible.

This should now match the old behavior before commit 9b9879fc03
("modules: catch concurrent module loads, treat them as idempotent"),
which used the different "wait for module to be ready" code in
module_patient_check_exists().

End result: a recursive module load will still block, but now a signal
will interrupt it and fail the second module load, at which point the
first module will successfully complete loading.

Fixes: 9b9879fc03 ("modules: catch concurrent module loads, treat them as idempotent")
Cc: Russell King <linux@armlinux.org.uk>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2024-08-09 08:33:28 -07:00

3418 lines
87 KiB
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2002 Richard Henderson
* Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
* Copyright (C) 2023 Luis Chamberlain <mcgrof@kernel.org>
*/
#define INCLUDE_VERMAGIC
#include <linux/export.h>
#include <linux/extable.h>
#include <linux/moduleloader.h>
#include <linux/module_signature.h>
#include <linux/trace_events.h>
#include <linux/init.h>
#include <linux/kallsyms.h>
#include <linux/buildid.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/kernel_read_file.h>
#include <linux/kstrtox.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/elf.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/fcntl.h>
#include <linux/rcupdate.h>
#include <linux/capability.h>
#include <linux/cpu.h>
#include <linux/moduleparam.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/vermagic.h>
#include <linux/notifier.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/mutex.h>
#include <linux/rculist.h>
#include <linux/uaccess.h>
#include <asm/cacheflush.h>
#include <linux/set_memory.h>
#include <asm/mmu_context.h>
#include <linux/license.h>
#include <asm/sections.h>
#include <linux/tracepoint.h>
#include <linux/ftrace.h>
#include <linux/livepatch.h>
#include <linux/async.h>
#include <linux/percpu.h>
#include <linux/kmemleak.h>
#include <linux/jump_label.h>
#include <linux/pfn.h>
#include <linux/bsearch.h>
#include <linux/dynamic_debug.h>
#include <linux/audit.h>
#include <linux/cfi.h>
#include <linux/codetag.h>
#include <linux/debugfs.h>
#include <linux/execmem.h>
#include <uapi/linux/module.h>
#include "internal.h"
#define CREATE_TRACE_POINTS
#include <trace/events/module.h>
/*
* Mutex protects:
* 1) List of modules (also safely readable with preempt_disable),
* 2) module_use links,
* 3) mod_tree.addr_min/mod_tree.addr_max.
* (delete and add uses RCU list operations).
*/
DEFINE_MUTEX(module_mutex);
LIST_HEAD(modules);
/* Work queue for freeing init sections in success case */
static void do_free_init(struct work_struct *w);
static DECLARE_WORK(init_free_wq, do_free_init);
static LLIST_HEAD(init_free_list);
struct mod_tree_root mod_tree __cacheline_aligned = {
.addr_min = -1UL,
};
struct symsearch {
const struct kernel_symbol *start, *stop;
const s32 *crcs;
enum mod_license license;
};
/*
* Bounds of module memory, for speeding up __module_address.
* Protected by module_mutex.
*/
static void __mod_update_bounds(enum mod_mem_type type __maybe_unused, void *base,
unsigned int size, struct mod_tree_root *tree)
{
unsigned long min = (unsigned long)base;
unsigned long max = min + size;
#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
if (mod_mem_type_is_core_data(type)) {
if (min < tree->data_addr_min)
tree->data_addr_min = min;
if (max > tree->data_addr_max)
tree->data_addr_max = max;
return;
}
#endif
if (min < tree->addr_min)
tree->addr_min = min;
if (max > tree->addr_max)
tree->addr_max = max;
}
static void mod_update_bounds(struct module *mod)
{
for_each_mod_mem_type(type) {
struct module_memory *mod_mem = &mod->mem[type];
if (mod_mem->size)
__mod_update_bounds(type, mod_mem->base, mod_mem->size, &mod_tree);
}
}
/* Block module loading/unloading? */
int modules_disabled;
core_param(nomodule, modules_disabled, bint, 0);
/* Waiting for a module to finish initializing? */
static DECLARE_WAIT_QUEUE_HEAD(module_wq);
static BLOCKING_NOTIFIER_HEAD(module_notify_list);
int register_module_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&module_notify_list, nb);
}
EXPORT_SYMBOL(register_module_notifier);
int unregister_module_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&module_notify_list, nb);
}
EXPORT_SYMBOL(unregister_module_notifier);
/*
* We require a truly strong try_module_get(): 0 means success.
* Otherwise an error is returned due to ongoing or failed
* initialization etc.
*/
static inline int strong_try_module_get(struct module *mod)
{
BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
if (mod && mod->state == MODULE_STATE_COMING)
return -EBUSY;
if (try_module_get(mod))
return 0;
else
return -ENOENT;
}
static inline void add_taint_module(struct module *mod, unsigned flag,
enum lockdep_ok lockdep_ok)
{
add_taint(flag, lockdep_ok);
set_bit(flag, &mod->taints);
}
/*
* A thread that wants to hold a reference to a module only while it
* is running can call this to safely exit.
*/
void __noreturn __module_put_and_kthread_exit(struct module *mod, long code)
{
module_put(mod);
kthread_exit(code);
}
EXPORT_SYMBOL(__module_put_and_kthread_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;
}
/* Find a module section: 0 means not found. Ignores SHF_ALLOC flag. */
static unsigned int find_any_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];
if (strcmp(info->secstrings + shdr->sh_name, name) == 0)
return i;
}
return 0;
}
/*
* Find a module section, or NULL. Fill in number of "objects" in section.
* Ignores SHF_ALLOC flag.
*/
static __maybe_unused void *any_section_objs(const struct load_info *info,
const char *name,
size_t object_size,
unsigned int *num)
{
unsigned int sec = find_any_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;
}
#ifndef CONFIG_MODVERSIONS
#define symversion(base, idx) NULL
#else
#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
#endif
static const char *kernel_symbol_name(const struct kernel_symbol *sym)
{
#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
return offset_to_ptr(&sym->name_offset);
#else
return sym->name;
#endif
}
static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
{
#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
if (!sym->namespace_offset)
return NULL;
return offset_to_ptr(&sym->namespace_offset);
#else
return sym->namespace;
#endif
}
int cmp_name(const void *name, const void *sym)
{
return strcmp(name, kernel_symbol_name(sym));
}
static bool find_exported_symbol_in_section(const struct symsearch *syms,
struct module *owner,
struct find_symbol_arg *fsa)
{
struct kernel_symbol *sym;
if (!fsa->gplok && syms->license == GPL_ONLY)
return false;
sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
sizeof(struct kernel_symbol), cmp_name);
if (!sym)
return false;
fsa->owner = owner;
fsa->crc = symversion(syms->crcs, sym - syms->start);
fsa->sym = sym;
fsa->license = syms->license;
return true;
}
/*
* Find an exported symbol and return it, along with, (optional) crc and
* (optional) module which owns it. Needs preempt disabled or module_mutex.
*/
bool find_symbol(struct find_symbol_arg *fsa)
{
static const struct symsearch arr[] = {
{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
NOT_GPL_ONLY },
{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
__start___kcrctab_gpl,
GPL_ONLY },
};
struct module *mod;
unsigned int i;
module_assert_mutex_or_preempt();
for (i = 0; i < ARRAY_SIZE(arr); i++)
if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
return true;
list_for_each_entry_rcu(mod, &modules, list,
lockdep_is_held(&module_mutex)) {
struct symsearch arr[] = {
{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
NOT_GPL_ONLY },
{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
mod->gpl_crcs,
GPL_ONLY },
};
if (mod->state == MODULE_STATE_UNFORMED)
continue;
for (i = 0; i < ARRAY_SIZE(arr); i++)
if (find_exported_symbol_in_section(&arr[i], mod, fsa))
return true;
}
pr_debug("Failed to find symbol %s\n", fsa->name);
return false;
}
/*
* Search for module by name: must hold module_mutex (or preempt disabled
* for read-only access).
*/
struct module *find_module_all(const char *name, size_t len,
bool even_unformed)
{
struct module *mod;
module_assert_mutex_or_preempt();
list_for_each_entry_rcu(mod, &modules, list,
lockdep_is_held(&module_mutex)) {
if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
continue;
if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
return mod;
}
return NULL;
}
struct module *find_module(const char *name)
{
return find_module_all(name, strlen(name), false);
}
#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.
*
* Return: %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 struct {
char name[MODULE_NAME_LEN + 1];
char taints[MODULE_FLAGS_BUF_SIZE];
} last_unloaded_module;
#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)
return 1;
}
pr_debug("%s does not use %s!\n", a->name, b->name);
return 0;
}
/*
* Module a uses b
* - we add 'a' as a "source", 'b' as a "target" of module use
* - the module_use is added to the list of 'b' sources (so
* 'b' can walk the list to see who sourced them), and of 'a'
* targets (so 'a' can see what modules it targets).
*/
static int add_module_usage(struct module *a, struct module *b)
{
struct module_use *use;
pr_debug("Allocating new usage for %s.\n", a->name);
use = kmalloc(sizeof(*use), GFP_ATOMIC);
if (!use)
return -ENOMEM;
use->source = a;
use->target = b;
list_add(&use->source_list, &b->source_list);
list_add(&use->target_list, &a->target_list);
return 0;
}
/* Module a uses b: caller needs module_mutex() */
static int ref_module(struct module *a, struct module *b)
{
int err;
if (b == NULL || already_uses(a, b))
return 0;
/* If module isn't available, we fail. */
err = strong_try_module_get(b);
if (err)
return err;
err = add_module_usage(a, b);
if (err) {
module_put(b);
return err;
}
return 0;
}
/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
struct module_use *use, *tmp;
mutex_lock(&module_mutex);
list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
struct module *i = use->target;
pr_debug("%s unusing %s\n", mod->name, i->name);
module_put(i);
list_del(&use->source_list);
list_del(&use->target_list);
kfree(use);
}
mutex_unlock(&module_mutex);
}
#ifdef CONFIG_MODULE_FORCE_UNLOAD
static inline int try_force_unload(unsigned int flags)
{
int ret = (flags & O_TRUNC);
if (ret)
add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
return ret;
}
#else
static inline int try_force_unload(unsigned int flags)
{
return 0;
}
#endif /* CONFIG_MODULE_FORCE_UNLOAD */
/* Try to release refcount of module, 0 means success. */
static int try_release_module_ref(struct module *mod)
{
int ret;
/* Try to decrement refcnt which we set at loading */
ret = atomic_sub_return(MODULE_REF_BASE, &mod->refcnt);
BUG_ON(ret < 0);
if (ret)
/* Someone can put this right now, recover with checking */
ret = atomic_add_unless(&mod->refcnt, MODULE_REF_BASE, 0);
return ret;
}
static int try_stop_module(struct module *mod, int flags, int *forced)
{
/* If it's not unused, quit unless we're forcing. */
if (try_release_module_ref(mod) != 0) {
*forced = try_force_unload(flags);
if (!(*forced))
return -EWOULDBLOCK;
}
/* Mark it as dying. */
mod->state = MODULE_STATE_GOING;
return 0;
}
/**
* module_refcount() - return the refcount or -1 if unloading
* @mod: the module we're checking
*
* Return:
* -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];
char buf[MODULE_FLAGS_BUF_SIZE];
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;
}
}
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 and taints of the last unloaded module for diagnostic purposes */
strscpy(last_unloaded_module.name, mod->name, sizeof(last_unloaded_module.name));
strscpy(last_unloaded_module.taints, module_flags(mod, buf, false), sizeof(last_unloaded_module.taints));
free_module(mod);
/* someone could wait for the module in add_unformed_module() */
wake_up_all(&module_wq);
return 0;
out:
mutex_unlock(&module_mutex);
return ret;
}
void __symbol_put(const char *symbol)
{
struct find_symbol_arg fsa = {
.name = symbol,
.gplok = true,
};
preempt_disable();
BUG_ON(!find_symbol(&fsa));
module_put(fsa.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) {
atomic_inc(&module->refcnt);
trace_module_get(module, _RET_IP_);
}
}
EXPORT_SYMBOL(__module_get);
bool try_module_get(struct module *module)
{
bool ret = true;
if (module) {
/* 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;
}
return ret;
}
EXPORT_SYMBOL(try_module_get);
void module_put(struct module *module)
{
int ret;
if (module) {
ret = atomic_dec_if_positive(&module->refcnt);
WARN_ON(ret < 0); /* Failed to put refcount */
trace_module_put(module, _RET_IP_);
}
}
EXPORT_SYMBOL(module_put);
#else /* !CONFIG_MODULE_UNLOAD */
static inline void module_unload_free(struct module *mod)
{
}
static int ref_module(struct module *a, struct module *b)
{
return strong_try_module_get(b);
}
static inline int module_unload_init(struct module *mod)
{
return 0;
}
#endif /* CONFIG_MODULE_UNLOAD */
size_t module_flags_taint(unsigned long taints, char *buf)
{
size_t l = 0;
int i;
for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
if (taint_flags[i].module && test_bit(i, &taints))
buf[l++] = taint_flags[i].c_true;
}
return l;
}
static ssize_t show_initstate(struct module_attribute *mattr,
struct module_kobject *mk, char *buffer)
{
const char *state = "unknown";
switch (mk->mod->state) {
case MODULE_STATE_LIVE:
state = "live";
break;
case MODULE_STATE_COMING:
state = "coming";
break;
case MODULE_STATE_GOING:
state = "going";
break;
default:
BUG();
}
return sprintf(buffer, "%s\n", state);
}
static struct module_attribute modinfo_initstate =
__ATTR(initstate, 0444, show_initstate, NULL);
static ssize_t store_uevent(struct module_attribute *mattr,
struct module_kobject *mk,
const char *buffer, size_t count)
{
int rc;
rc = kobject_synth_uevent(&mk->kobj, buffer, count);
return rc ? rc : count;
}
struct module_attribute module_uevent =
__ATTR(uevent, 0200, NULL, store_uevent);
static ssize_t show_coresize(struct module_attribute *mattr,
struct module_kobject *mk, char *buffer)
{
unsigned int size = mk->mod->mem[MOD_TEXT].size;
if (!IS_ENABLED(CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC)) {
for_class_mod_mem_type(type, core_data)
size += mk->mod->mem[type].size;
}
return sprintf(buffer, "%u\n", size);
}
static struct module_attribute modinfo_coresize =
__ATTR(coresize, 0444, show_coresize, NULL);
#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
static ssize_t show_datasize(struct module_attribute *mattr,
struct module_kobject *mk, char *buffer)
{
unsigned int size = 0;
for_class_mod_mem_type(type, core_data)
size += mk->mod->mem[type].size;
return sprintf(buffer, "%u\n", size);
}
static struct module_attribute modinfo_datasize =
__ATTR(datasize, 0444, show_datasize, NULL);
#endif
static ssize_t show_initsize(struct module_attribute *mattr,
struct module_kobject *mk, char *buffer)
{
unsigned int size = 0;
for_class_mod_mem_type(type, init)
size += mk->mod->mem[type].size;
return sprintf(buffer, "%u\n", 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->taints, buffer);
buffer[l++] = '\n';
return l;
}
static struct module_attribute modinfo_taint =
__ATTR(taint, 0444, show_taint, NULL);
struct module_attribute *modinfo_attrs[] = {
&module_uevent,
&modinfo_version,
&modinfo_srcversion,
&modinfo_initstate,
&modinfo_coresize,
#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
&modinfo_datasize,
#endif
&modinfo_initsize,
&modinfo_taint,
#ifdef CONFIG_MODULE_UNLOAD
&modinfo_refcnt,
#endif
NULL,
};
size_t modinfo_attrs_count = ARRAY_SIZE(modinfo_attrs);
static const char vermagic[] = VERMAGIC_STRING;
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
}
/* Parse tag=value strings from .modinfo section */
char *module_next_tag_pair(char *string, unsigned long *secsize)
{
/* Skip non-zero chars */
while (string[0]) {
string++;
if ((*secsize)-- <= 1)
return NULL;
}
/* Skip any zero padding. */
while (!string[0]) {
string++;
if ((*secsize)-- <= 1)
return NULL;
}
return string;
}
static char *get_next_modinfo(const struct load_info *info, const char *tag,
char *prev)
{
char *p;
unsigned int taglen = strlen(tag);
Elf_Shdr *infosec = &info->sechdrs[info->index.info];
unsigned long size = infosec->sh_size;
/*
* get_modinfo() calls made before rewrite_section_headers()
* must use sh_offset, as sh_addr isn't set!
*/
char *modinfo = (char *)info->hdr + infosec->sh_offset;
if (prev) {
size -= prev - modinfo;
modinfo = module_next_tag_pair(prev, &size);
}
for (p = modinfo; p; p = module_next_tag_pair(p, &size)) {
if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
return p + taglen + 1;
}
return NULL;
}
static char *get_modinfo(const struct load_info *info, const char *tag)
{
return get_next_modinfo(info, tag, NULL);
}
static int verify_namespace_is_imported(const struct load_info *info,
const struct kernel_symbol *sym,
struct module *mod)
{
const char *namespace;
char *imported_namespace;
namespace = kernel_symbol_namespace(sym);
if (namespace && namespace[0]) {
for_each_modinfo_entry(imported_namespace, info, "import_ns") {
if (strcmp(namespace, imported_namespace) == 0)
return 0;
}
#ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
pr_warn(
#else
pr_err(
#endif
"%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
mod->name, kernel_symbol_name(sym), namespace);
#ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
return -EINVAL;
#endif
}
return 0;
}
static bool inherit_taint(struct module *mod, struct module *owner, const char *name)
{
if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
return true;
if (mod->using_gplonly_symbols) {
pr_err("%s: module using GPL-only symbols uses symbols %s from proprietary module %s.\n",
mod->name, name, owner->name);
return false;
}
if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
pr_warn("%s: module uses symbols %s from proprietary module %s, inheriting taint.\n",
mod->name, name, owner->name);
set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints);
}
return true;
}
/* Resolve a symbol for this module. I.e. if we find one, record usage. */
static const struct kernel_symbol *resolve_symbol(struct module *mod,
const struct load_info *info,
const char *name,
char ownername[])
{
struct find_symbol_arg fsa = {
.name = name,
.gplok = !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
.warn = true,
};
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);
if (!find_symbol(&fsa))
goto unlock;
if (fsa.license == GPL_ONLY)
mod->using_gplonly_symbols = true;
if (!inherit_taint(mod, fsa.owner, name)) {
fsa.sym = NULL;
goto getname;
}
if (!check_version(info, name, mod, fsa.crc)) {
fsa.sym = ERR_PTR(-EINVAL);
goto getname;
}
err = verify_namespace_is_imported(info, fsa.sym, mod);
if (err) {
fsa.sym = ERR_PTR(err);
goto getname;
}
err = ref_module(mod, fsa.owner);
if (err) {
fsa.sym = ERR_PTR(err);
goto getname;
}
getname:
/* We must make copy under the lock if we failed to get ref. */
strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
unlock:
mutex_unlock(&module_mutex);
return fsa.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;
}
void __weak module_arch_cleanup(struct module *mod)
{
}
void __weak module_arch_freeing_init(struct module *mod)
{
}
static int module_memory_alloc(struct module *mod, enum mod_mem_type type)
{
unsigned int size = PAGE_ALIGN(mod->mem[type].size);
enum execmem_type execmem_type;
void *ptr;
mod->mem[type].size = size;
if (mod_mem_type_is_data(type))
execmem_type = EXECMEM_MODULE_DATA;
else
execmem_type = EXECMEM_MODULE_TEXT;
ptr = execmem_alloc(execmem_type, size);
if (!ptr)
return -ENOMEM;
/*
* The pointer to these blocks of memory are stored on the module
* structure and we keep that around so long as the module is
* around. We only free that memory when we unload the module.
* Just mark them as not being a leak then. The .init* ELF
* sections *do* get freed after boot so we *could* treat them
* slightly differently with kmemleak_ignore() and only grey
* them out as they work as typical memory allocations which
* *do* eventually get freed, but let's just keep things simple
* and avoid *any* false positives.
*/
kmemleak_not_leak(ptr);
memset(ptr, 0, size);
mod->mem[type].base = ptr;
return 0;
}
static void module_memory_free(struct module *mod, enum mod_mem_type type,
bool unload_codetags)
{
void *ptr = mod->mem[type].base;
if (!unload_codetags && mod_mem_type_is_core_data(type))
return;
execmem_free(ptr);
}
static void free_mod_mem(struct module *mod, bool unload_codetags)
{
for_each_mod_mem_type(type) {
struct module_memory *mod_mem = &mod->mem[type];
if (type == MOD_DATA)
continue;
/* Free lock-classes; relies on the preceding sync_rcu(). */
lockdep_free_key_range(mod_mem->base, mod_mem->size);
if (mod_mem->size)
module_memory_free(mod, type, unload_codetags);
}
/* MOD_DATA hosts mod, so free it at last */
lockdep_free_key_range(mod->mem[MOD_DATA].base, mod->mem[MOD_DATA].size);
module_memory_free(mod, MOD_DATA, unload_codetags);
}
/* Free a module, remove from lists, etc. */
static void free_module(struct module *mod)
{
bool unload_codetags;
trace_module_free(mod);
unload_codetags = codetag_unload_module(mod);
if (!unload_codetags)
pr_warn("%s: memory allocation(s) from the module still alive, cannot unload cleanly\n",
mod->name);
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);
/* Arch-specific cleanup. */
module_arch_cleanup(mod);
/* Module unload stuff */
module_unload_free(mod);
/* Free any allocated parameters. */
destroy_params(mod->kp, mod->num_kp);
if (is_livepatch_module(mod))
free_module_elf(mod);
/* Now we can delete it from the lists */
mutex_lock(&module_mutex);
/* Unlink carefully: kallsyms could be walking list. */
list_del_rcu(&mod->list);
mod_tree_remove(mod);
/* Remove this module from bug list, this uses list_del_rcu */
module_bug_cleanup(mod);
/* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */
synchronize_rcu();
if (try_add_tainted_module(mod))
pr_err("%s: adding tainted module to the unloaded tainted modules list failed.\n",
mod->name);
mutex_unlock(&module_mutex);
/* This may be empty, but that's OK */
module_arch_freeing_init(mod);
kfree(mod->args);
percpu_modfree(mod);
free_mod_mem(mod, unload_codetags);
}
void *__symbol_get(const char *symbol)
{
struct find_symbol_arg fsa = {
.name = symbol,
.gplok = true,
.warn = true,
};
preempt_disable();
if (!find_symbol(&fsa))
goto fail;
if (fsa.license != GPL_ONLY) {
pr_warn("failing symbol_get of non-GPLONLY symbol %s.\n",
symbol);
goto fail;
}
if (strong_try_module_get(fsa.owner))
goto fail;
preempt_enable();
return (void *)kernel_symbol_value(fsa.sym);
fail:
preempt_enable();
return NULL;
}
EXPORT_SYMBOL_GPL(__symbol_get);
/*
* Ensure that an exported symbol [global namespace] does not already exist
* in the kernel or in some other module's exported symbol table.
*
* You must hold the module_mutex.
*/
static int verify_exported_symbols(struct module *mod)
{
unsigned int i;
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 },
};
for (i = 0; i < ARRAY_SIZE(arr); i++) {
for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
struct find_symbol_arg fsa = {
.name = kernel_symbol_name(s),
.gplok = true,
};
if (find_symbol(&fsa)) {
pr_err("%s: exports duplicate symbol %s"
" (owned by %s)\n",
mod->name, kernel_symbol_name(s),
module_name(fsa.owner));
return -ENOEXEC;
}
}
}
return 0;
}
static bool ignore_undef_symbol(Elf_Half emachine, const char *name)
{
/*
* On x86, PIC code and Clang non-PIC code may have call foo@PLT. GNU as
* before 2.37 produces an unreferenced _GLOBAL_OFFSET_TABLE_ on x86-64.
* i386 has a similar problem but may not deserve a fix.
*
* If we ever have to ignore many symbols, consider refactoring the code to
* only warn if referenced by a relocation.
*/
if (emachine == EM_386 || emachine == EM_X86_64)
return !strcmp(name, "_GLOBAL_OFFSET_TABLE_");
return false;
}
/* 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 %s\n",
(long)sym[i].st_value, name);
break;
case SHN_LIVEPATCH:
/* Livepatch symbols are resolved by livepatch */
break;
case SHN_UNDEF:
ksym = resolve_symbol_wait(mod, info, name);
/* Ok if resolved. */
if (ksym && !IS_ERR(ksym)) {
sym[i].st_value = kernel_symbol_value(ksym);
break;
}
/* Ok if weak or ignored. */
if (!ksym &&
(ELF_ST_BIND(sym[i].st_info) == STB_WEAK ||
ignore_undef_symbol(info->hdr->e_machine, name)))
break;
ret = PTR_ERR(ksym) ?: -ENOENT;
pr_warn("%s: Unknown symbol %s (err %d)\n",
mod->name, name, ret);
break;
default:
/* Divert to percpu allocation if a percpu var. */
if (sym[i].st_shndx == info->index.pcpu)
secbase = (unsigned long)mod_percpu(mod);
else
secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
sym[i].st_value += secbase;
break;
}
}
return ret;
}
static int apply_relocations(struct module *mod, const struct load_info *info)
{
unsigned int i;
int err = 0;
/* Now do relocations. */
for (i = 1; i < info->hdr->e_shnum; i++) {
unsigned int infosec = info->sechdrs[i].sh_info;
/* Not a valid relocation section? */
if (infosec >= info->hdr->e_shnum)
continue;
/* Don't bother with non-allocated sections */
if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
continue;
if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
err = klp_apply_section_relocs(mod, info->sechdrs,
info->secstrings,
info->strtab,
info->index.sym, i,
NULL);
else if (info->sechdrs[i].sh_type == SHT_REL)
err = apply_relocate(info->sechdrs, info->strtab,
info->index.sym, i, mod);
else if (info->sechdrs[i].sh_type == SHT_RELA)
err = apply_relocate_add(info->sechdrs, info->strtab,
info->index.sym, i, mod);
if (err < 0)
break;
}
return err;
}
/* Additional bytes needed by arch in front of individual sections */
unsigned int __weak arch_mod_section_prepend(struct module *mod,
unsigned int section)
{
/* default implementation just returns zero */
return 0;
}
long module_get_offset_and_type(struct module *mod, enum mod_mem_type type,
Elf_Shdr *sechdr, unsigned int section)
{
long offset;
long mask = ((unsigned long)(type) & SH_ENTSIZE_TYPE_MASK) << SH_ENTSIZE_TYPE_SHIFT;
mod->mem[type].size += arch_mod_section_prepend(mod, section);
offset = ALIGN(mod->mem[type].size, sechdr->sh_addralign ?: 1);
mod->mem[type].size = offset + sechdr->sh_size;
WARN_ON_ONCE(offset & mask);
return offset | mask;
}
bool module_init_layout_section(const char *sname)
{
#ifndef CONFIG_MODULE_UNLOAD
if (module_exit_section(sname))
return true;
#endif
return module_init_section(sname);
}
static void __layout_sections(struct module *mod, struct load_info *info, bool is_init)
{
unsigned int m, i;
static const unsigned long 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 }
};
static const int core_m_to_mem_type[] = {
MOD_TEXT,
MOD_RODATA,
MOD_RO_AFTER_INIT,
MOD_DATA,
MOD_DATA,
};
static const int init_m_to_mem_type[] = {
MOD_INIT_TEXT,
MOD_INIT_RODATA,
MOD_INVALID,
MOD_INIT_DATA,
MOD_INIT_DATA,
};
for (m = 0; m < ARRAY_SIZE(masks); ++m) {
enum mod_mem_type type = is_init ? init_m_to_mem_type[m] : core_m_to_mem_type[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
|| is_init != module_init_layout_section(sname))
continue;
if (WARN_ON_ONCE(type == MOD_INVALID))
continue;
s->sh_entsize = module_get_offset_and_type(mod, type, s, i);
pr_debug("\t%s\n", sname);
}
}
}
/*
* 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)
{
unsigned int i;
for (i = 0; i < info->hdr->e_shnum; i++)
info->sechdrs[i].sh_entsize = ~0UL;
pr_debug("Core section allocation order for %s:\n", mod->name);
__layout_sections(mod, info, false);
pr_debug("Init section allocation order for %s:\n", mod->name);
__layout_sections(mod, info, true);
}
static void module_license_taint_check(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);
}
}
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);
}
}
bool __weak module_init_section(const char *name)
{
return strstarts(name, ".init");
}
bool __weak module_exit_section(const char *name)
{
return strstarts(name, ".exit");
}
static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr)
{
#if defined(CONFIG_64BIT)
unsigned long long secend;
#else
unsigned long secend;
#endif
/*
* Check for both overflow and offset/size being
* too large.
*/
secend = shdr->sh_offset + shdr->sh_size;
if (secend < shdr->sh_offset || secend > info->len)
return -ENOEXEC;
return 0;
}
/*
* Check userspace passed ELF module against our expectations, and cache
* useful variables for further processing as we go.
*
* This does basic validity checks against section offsets and sizes, the
* section name string table, and the indices used for it (sh_name).
*
* As a last step, since we're already checking the ELF sections we cache
* useful variables which will be used later for our convenience:
*
* o pointers to section headers
* o cache the modinfo symbol section
* o cache the string symbol section
* o cache the module section
*
* As a last step we set info->mod to the temporary copy of the module in
* info->hdr. The final one will be allocated in move_module(). Any
* modifications we make to our copy of the module will be carried over
* to the final minted module.
*/
static int elf_validity_cache_copy(struct load_info *info, int flags)
{
unsigned int i;
Elf_Shdr *shdr, *strhdr;
int err;
unsigned int num_mod_secs = 0, mod_idx;
unsigned int num_info_secs = 0, info_idx;
unsigned int num_sym_secs = 0, sym_idx;
if (info->len < sizeof(*(info->hdr))) {
pr_err("Invalid ELF header len %lu\n", info->len);
goto no_exec;
}
if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0) {
pr_err("Invalid ELF header magic: != %s\n", ELFMAG);
goto no_exec;
}
if (info->hdr->e_type != ET_REL) {
pr_err("Invalid ELF header type: %u != %u\n",
info->hdr->e_type, ET_REL);
goto no_exec;
}
if (!elf_check_arch(info->hdr)) {
pr_err("Invalid architecture in ELF header: %u\n",
info->hdr->e_machine);
goto no_exec;
}
if (!module_elf_check_arch(info->hdr)) {
pr_err("Invalid module architecture in ELF header: %u\n",
info->hdr->e_machine);
goto no_exec;
}
if (info->hdr->e_shentsize != sizeof(Elf_Shdr)) {
pr_err("Invalid ELF section header size\n");
goto no_exec;
}
/*
* e_shnum is 16 bits, and sizeof(Elf_Shdr) is
* known and small. So e_shnum * sizeof(Elf_Shdr)
* will not overflow unsigned long on any platform.
*/
if (info->hdr->e_shoff >= info->len
|| (info->hdr->e_shnum * sizeof(Elf_Shdr) >
info->len - info->hdr->e_shoff)) {
pr_err("Invalid ELF section header overflow\n");
goto no_exec;
}
info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
/*
* Verify if the section name table index is valid.
*/
if (info->hdr->e_shstrndx == SHN_UNDEF
|| info->hdr->e_shstrndx >= info->hdr->e_shnum) {
pr_err("Invalid ELF section name index: %d || e_shstrndx (%d) >= e_shnum (%d)\n",
info->hdr->e_shstrndx, info->hdr->e_shstrndx,
info->hdr->e_shnum);
goto no_exec;
}
strhdr = &info->sechdrs[info->hdr->e_shstrndx];
err = validate_section_offset(info, strhdr);
if (err < 0) {
pr_err("Invalid ELF section hdr(type %u)\n", strhdr->sh_type);
return err;
}
/*
* The section name table must be NUL-terminated, as required
* by the spec. This makes strcmp and pr_* calls that access
* strings in the section safe.
*/
info->secstrings = (void *)info->hdr + strhdr->sh_offset;
if (strhdr->sh_size == 0) {
pr_err("empty section name table\n");
goto no_exec;
}
if (info->secstrings[strhdr->sh_size - 1] != '\0') {
pr_err("ELF Spec violation: section name table isn't null terminated\n");
goto no_exec;
}
/*
* The code assumes that section 0 has a length of zero and
* an addr of zero, so check for it.
*/
if (info->sechdrs[0].sh_type != SHT_NULL
|| info->sechdrs[0].sh_size != 0
|| info->sechdrs[0].sh_addr != 0) {
pr_err("ELF Spec violation: section 0 type(%d)!=SH_NULL or non-zero len or addr\n",
info->sechdrs[0].sh_type);
goto no_exec;
}
for (i = 1; i < info->hdr->e_shnum; i++) {
shdr = &info->sechdrs[i];
switch (shdr->sh_type) {
case SHT_NULL:
case SHT_NOBITS:
continue;
case SHT_SYMTAB:
if (shdr->sh_link == SHN_UNDEF
|| shdr->sh_link >= info->hdr->e_shnum) {
pr_err("Invalid ELF sh_link!=SHN_UNDEF(%d) or (sh_link(%d) >= hdr->e_shnum(%d)\n",
shdr->sh_link, shdr->sh_link,
info->hdr->e_shnum);
goto no_exec;
}
num_sym_secs++;
sym_idx = i;
fallthrough;
default:
err = validate_section_offset(info, shdr);
if (err < 0) {
pr_err("Invalid ELF section in module (section %u type %u)\n",
i, shdr->sh_type);
return err;
}
if (strcmp(info->secstrings + shdr->sh_name,
".gnu.linkonce.this_module") == 0) {
num_mod_secs++;
mod_idx = i;
} else if (strcmp(info->secstrings + shdr->sh_name,
".modinfo") == 0) {
num_info_secs++;
info_idx = i;
}
if (shdr->sh_flags & SHF_ALLOC) {
if (shdr->sh_name >= strhdr->sh_size) {
pr_err("Invalid ELF section name in module (section %u type %u)\n",
i, shdr->sh_type);
return -ENOEXEC;
}
}
break;
}
}
if (num_info_secs > 1) {
pr_err("Only one .modinfo section must exist.\n");
goto no_exec;
} else if (num_info_secs == 1) {
/* Try to find a name early so we can log errors with a module name */
info->index.info = info_idx;
info->name = get_modinfo(info, "name");
}
if (num_sym_secs != 1) {
pr_warn("%s: module has no symbols (stripped?)\n",
info->name ?: "(missing .modinfo section or name field)");
goto no_exec;
}
/* Sets internal symbols and strings. */
info->index.sym = sym_idx;
shdr = &info->sechdrs[sym_idx];
info->index.str = shdr->sh_link;
info->strtab = (char *)info->hdr + info->sechdrs[info->index.str].sh_offset;
/*
* The ".gnu.linkonce.this_module" ELF section is special. It is
* what modpost uses to refer to __this_module and let's use rely
* on THIS_MODULE to point to &__this_module properly. The kernel's
* modpost declares it on each modules's *.mod.c file. If the struct
* module of the kernel changes a full kernel rebuild is required.
*
* We have a few expectaions for this special section, the following
* code validates all this for us:
*
* o Only one section must exist
* o We expect the kernel to always have to allocate it: SHF_ALLOC
* o The section size must match the kernel's run time's struct module
* size
*/
if (num_mod_secs != 1) {
pr_err("module %s: Only one .gnu.linkonce.this_module section must exist.\n",
info->name ?: "(missing .modinfo section or name field)");
goto no_exec;
}
shdr = &info->sechdrs[mod_idx];
/*
* This is already implied on the switch above, however let's be
* pedantic about it.
*/
if (shdr->sh_type == SHT_NOBITS) {
pr_err("module %s: .gnu.linkonce.this_module section must have a size set\n",
info->name ?: "(missing .modinfo section or name field)");
goto no_exec;
}
if (!(shdr->sh_flags & SHF_ALLOC)) {
pr_err("module %s: .gnu.linkonce.this_module must occupy memory during process execution\n",
info->name ?: "(missing .modinfo section or name field)");
goto no_exec;
}
if (shdr->sh_size != sizeof(struct module)) {
pr_err("module %s: .gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n",
info->name ?: "(missing .modinfo section or name field)");
goto no_exec;
}
info->index.mod = mod_idx;
/* This is temporary: point mod into copy of data. */
info->mod = (void *)info->hdr + shdr->sh_offset;
/*
* If we didn't load the .modinfo 'name' field earlier, fall back to
* on-disk struct mod 'name' field.
*/
if (!info->name)
info->name = info->mod->name;
if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
info->index.vers = 0; /* Pretend no __versions section! */
else
info->index.vers = find_sec(info, "__versions");
info->index.pcpu = find_pcpusec(info);
return 0;
no_exec:
return -ENOEXEC;
}
#define COPY_CHUNK_SIZE (16*PAGE_SIZE)
static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned long len)
{
do {
unsigned long n = min(len, COPY_CHUNK_SIZE);
if (copy_from_user(dst, usrc, n) != 0)
return -EFAULT;
cond_resched();
dst += n;
usrc += n;
len -= n;
} while (len);
return 0;
}
static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
{
if (!get_modinfo(info, "livepatch"))
/* Nothing more to do */
return 0;
if (set_livepatch_module(mod))
return 0;
pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
mod->name);
return -ENOEXEC;
}
static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
{
if (retpoline_module_ok(get_modinfo(info, "retpoline")))
return;
pr_warn("%s: loading module not compiled with retpoline compiler.\n",
mod->name);
}
/* Sets info->hdr and info->len. */
static int copy_module_from_user(const void __user *umod, unsigned long len,
struct load_info *info)
{
int err;
info->len = len;
if (info->len < sizeof(*(info->hdr)))
return -ENOEXEC;
err = security_kernel_load_data(LOADING_MODULE, true);
if (err)
return err;
/* Suck in entire file: we'll want most of it. */
info->hdr = __vmalloc(info->len, GFP_KERNEL | __GFP_NOWARN);
if (!info->hdr)
return -ENOMEM;
if (copy_chunked_from_user(info->hdr, umod, info->len) != 0) {
err = -EFAULT;
goto out;
}
err = security_kernel_post_load_data((char *)info->hdr, info->len,
LOADING_MODULE, "init_module");
out:
if (err)
vfree(info->hdr);
return err;
}
static void free_copy(struct load_info *info, int flags)
{
if (flags & MODULE_INIT_COMPRESSED_FILE)
module_decompress_cleanup(info);
else
vfree(info->hdr);
}
static int rewrite_section_headers(struct load_info *info, int flags)
{
unsigned int i;
/* This should always be true, but let's be sure. */
info->sechdrs[0].sh_addr = 0;
for (i = 1; i < info->hdr->e_shnum; i++) {
Elf_Shdr *shdr = &info->sechdrs[i];
/*
* Mark all sections sh_addr with their address in the
* temporary image.
*/
shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
}
/* Track but don't keep modinfo and version sections. */
info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
return 0;
}
/*
* These calls taint the kernel depending certain module circumstances */
static void module_augment_kernel_taints(struct module *mod, struct load_info *info)
{
int prev_taint = test_taint(TAINT_PROPRIETARY_MODULE);
if (!get_modinfo(info, "intree")) {
if (!test_taint(TAINT_OOT_MODULE))
pr_warn("%s: loading out-of-tree module taints kernel.\n",
mod->name);
add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
}
check_modinfo_retpoline(mod, info);
if (get_modinfo(info, "staging")) {
add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
pr_warn("%s: module is from the staging directory, the quality "
"is unknown, you have been warned.\n", mod->name);
}
if (is_livepatch_module(mod)) {
add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
mod->name);
}
module_license_taint_check(mod, get_modinfo(info, "license"));
if (get_modinfo(info, "test")) {
if (!test_taint(TAINT_TEST))
pr_warn("%s: loading test module taints kernel.\n",
mod->name);
add_taint_module(mod, TAINT_TEST, LOCKDEP_STILL_OK);
}
#ifdef CONFIG_MODULE_SIG
mod->sig_ok = info->sig_ok;
if (!mod->sig_ok) {
pr_notice_once("%s: module verification failed: signature "
"and/or required key missing - tainting "
"kernel\n", mod->name);
add_taint_module(mod, TAINT_UNSIGNED_MODULE, LOCKDEP_STILL_OK);
}
#endif
/*
* ndiswrapper is under GPL by itself, but loads proprietary modules.
* Don't use add_taint_module(), as it would prevent ndiswrapper from
* using GPL-only symbols it needs.
*/
if (strcmp(mod->name, "ndiswrapper") == 0)
add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE);
/* driverloader was caught wrongly pretending to be under GPL */
if (strcmp(mod->name, "driverloader") == 0)
add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
LOCKDEP_NOW_UNRELIABLE);
/* lve claims to be GPL but upstream won't provide source */
if (strcmp(mod->name, "lve") == 0)
add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
LOCKDEP_NOW_UNRELIABLE);
if (!prev_taint && test_taint(TAINT_PROPRIETARY_MODULE))
pr_warn("%s: module license taints kernel.\n", mod->name);
}
static int check_modinfo(struct module *mod, struct load_info *info, int flags)
{
const char *modmagic = get_modinfo(info, "vermagic");
int err;
if (flags & MODULE_INIT_IGNORE_VERMAGIC)
modmagic = NULL;
/* This is allowed: modprobe --force will invalidate it. */
if (!modmagic) {
err = try_to_force_load(mod, "bad vermagic");
if (err)
return err;
} else if (!same_magic(modmagic, vermagic, info->index.vers)) {
pr_err("%s: version magic '%s' should be '%s'\n",
info->name, modmagic, vermagic);
return -ENOEXEC;
}
err = check_modinfo_livepatch(mod, info);
if (err)
return err;
return 0;
}
static int find_module_sections(struct module *mod, struct load_info *info)
{
mod->kp = section_objs(info, "__param",
sizeof(*mod->kp), &mod->num_kp);
mod->syms = section_objs(info, "__ksymtab",
sizeof(*mod->syms), &mod->num_syms);
mod->crcs = section_addr(info, "__kcrctab");
mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
sizeof(*mod->gpl_syms),
&mod->num_gpl_syms);
mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
#ifdef CONFIG_CONSTRUCTORS
mod->ctors = section_objs(info, ".ctors",
sizeof(*mod->ctors), &mod->num_ctors);
if (!mod->ctors)
mod->ctors = section_objs(info, ".init_array",
sizeof(*mod->ctors), &mod->num_ctors);
else if (find_sec(info, ".init_array")) {
/*
* This shouldn't happen with same compiler and binutils
* building all parts of the module.
*/
pr_warn("%s: has both .ctors and .init_array.\n",
mod->name);
return -EINVAL;
}
#endif
mod->noinstr_text_start = section_objs(info, ".noinstr.text", 1,
&mod->noinstr_text_size);
#ifdef CONFIG_TRACEPOINTS
mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
sizeof(*mod->tracepoints_ptrs),
&mod->num_tracepoints);
#endif
#ifdef CONFIG_TREE_SRCU
mod->srcu_struct_ptrs = section_objs(info, "___srcu_struct_ptrs",
sizeof(*mod->srcu_struct_ptrs),
&mod->num_srcu_structs);
#endif
#ifdef CONFIG_BPF_EVENTS
mod->bpf_raw_events = section_objs(info, "__bpf_raw_tp_map",
sizeof(*mod->bpf_raw_events),
&mod->num_bpf_raw_events);
#endif
#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
mod->btf_data = any_section_objs(info, ".BTF", 1, &mod->btf_data_size);
mod->btf_base_data = any_section_objs(info, ".BTF.base", 1,
&mod->btf_base_data_size);
#endif
#ifdef CONFIG_JUMP_LABEL
mod->jump_entries = section_objs(info, "__jump_table",
sizeof(*mod->jump_entries),
&mod->num_jump_entries);
#endif
#ifdef CONFIG_EVENT_TRACING
mod->trace_events = section_objs(info, "_ftrace_events",
sizeof(*mod->trace_events),
&mod->num_trace_events);
mod->trace_evals = section_objs(info, "_ftrace_eval_map",
sizeof(*mod->trace_evals),
&mod->num_trace_evals);
#endif
#ifdef CONFIG_TRACING
mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
sizeof(*mod->trace_bprintk_fmt_start),
&mod->num_trace_bprintk_fmt);
#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
/* sechdrs[0].sh_size is always zero */
mod->ftrace_callsites = section_objs(info, FTRACE_CALLSITE_SECTION,
sizeof(*mod->ftrace_callsites),
&mod->num_ftrace_callsites);
#endif
#ifdef CONFIG_FUNCTION_ERROR_INJECTION
mod->ei_funcs = section_objs(info, "_error_injection_whitelist",
sizeof(*mod->ei_funcs),
&mod->num_ei_funcs);
#endif
#ifdef CONFIG_KPROBES
mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
&mod->kprobes_text_size);
mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist",
sizeof(unsigned long),
&mod->num_kprobe_blacklist);
#endif
#ifdef CONFIG_PRINTK_INDEX
mod->printk_index_start = section_objs(info, ".printk_index",
sizeof(*mod->printk_index_start),
&mod->printk_index_size);
#endif
#ifdef CONFIG_HAVE_STATIC_CALL_INLINE
mod->static_call_sites = section_objs(info, ".static_call_sites",
sizeof(*mod->static_call_sites),
&mod->num_static_call_sites);
#endif
#if IS_ENABLED(CONFIG_KUNIT)
mod->kunit_suites = section_objs(info, ".kunit_test_suites",
sizeof(*mod->kunit_suites),
&mod->num_kunit_suites);
mod->kunit_init_suites = section_objs(info, ".kunit_init_test_suites",
sizeof(*mod->kunit_init_suites),
&mod->num_kunit_init_suites);
#endif
mod->extable = section_objs(info, "__ex_table",
sizeof(*mod->extable), &mod->num_exentries);
if (section_addr(info, "__obsparm"))
pr_warn("%s: Ignoring obsolete parameters\n", mod->name);
#ifdef CONFIG_DYNAMIC_DEBUG_CORE
mod->dyndbg_info.descs = section_objs(info, "__dyndbg",
sizeof(*mod->dyndbg_info.descs),
&mod->dyndbg_info.num_descs);
mod->dyndbg_info.classes = section_objs(info, "__dyndbg_classes",
sizeof(*mod->dyndbg_info.classes),
&mod->dyndbg_info.num_classes);
#endif
return 0;
}
static int move_module(struct module *mod, struct load_info *info)
{
int i;
enum mod_mem_type t = 0;
int ret = -ENOMEM;
for_each_mod_mem_type(type) {
if (!mod->mem[type].size) {
mod->mem[type].base = NULL;
continue;
}
ret = module_memory_alloc(mod, type);
if (ret) {
t = type;
goto out_enomem;
}
}
/* Transfer each section which specifies SHF_ALLOC */
pr_debug("Final section addresses for %s:\n", mod->name);
for (i = 0; i < info->hdr->e_shnum; i++) {
void *dest;
Elf_Shdr *shdr = &info->sechdrs[i];
enum mod_mem_type type = shdr->sh_entsize >> SH_ENTSIZE_TYPE_SHIFT;
if (!(shdr->sh_flags & SHF_ALLOC))
continue;
dest = mod->mem[type].base + (shdr->sh_entsize & SH_ENTSIZE_OFFSET_MASK);
if (shdr->sh_type != SHT_NOBITS) {
/*
* Our ELF checker already validated this, but let's
* be pedantic and make the goal clearer. We actually
* end up copying over all modifications made to the
* userspace copy of the entire struct module.
*/
if (i == info->index.mod &&
(WARN_ON_ONCE(shdr->sh_size != sizeof(struct module)))) {
ret = -ENOEXEC;
goto out_enomem;
}
memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
}
/*
* Update the userspace copy's ELF section address to point to
* our newly allocated memory as a pure convenience so that
* users of info can keep taking advantage and using the newly
* minted official memory area.
*/
shdr->sh_addr = (unsigned long)dest;
pr_debug("\t0x%lx 0x%.8lx %s\n", (long)shdr->sh_addr,
(long)shdr->sh_size, info->secstrings + shdr->sh_name);
}
return 0;
out_enomem:
for (t--; t >= 0; t--)
module_memory_free(mod, t, true);
return ret;
}
static int check_export_symbol_versions(struct module *mod)
{
#ifdef CONFIG_MODVERSIONS
if ((mod->num_syms && !mod->crcs) ||
(mod->num_gpl_syms && !mod->gpl_crcs)) {
return try_to_force_load(mod,
"no versions for exported symbols");
}
#endif
return 0;
}
static void flush_module_icache(const struct module *mod)
{
/*
* Flush the instruction cache, since we've played with text.
* Do it before processing of module parameters, so the module
* can provide parameter accessor functions of its own.
*/
for_each_mod_mem_type(type) {
const struct module_memory *mod_mem = &mod->mem[type];
if (mod_mem->size) {
flush_icache_range((unsigned long)mod_mem->base,
(unsigned long)mod_mem->base + mod_mem->size);
}
}
}
bool __weak module_elf_check_arch(Elf_Ehdr *hdr)
{
return true;
}
int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
Elf_Shdr *sechdrs,
char *secstrings,
struct module *mod)
{
return 0;
}
/* module_blacklist is a comma-separated list of module names */
static char *module_blacklist;
static bool blacklisted(const char *module_name)
{
const char *p;
size_t len;
if (!module_blacklist)
return false;
for (p = module_blacklist; *p; p += len) {
len = strcspn(p, ",");
if (strlen(module_name) == len && !memcmp(module_name, p, len))
return true;
if (p[len] == ',')
len++;
}
return false;
}
core_param(module_blacklist, module_blacklist, charp, 0400);
static struct module *layout_and_allocate(struct load_info *info, int flags)
{
struct module *mod;
unsigned int ndx;
int err;
/* Allow arches to frob section contents and sizes. */
err = module_frob_arch_sections(info->hdr, info->sechdrs,
info->secstrings, info->mod);
if (err < 0)
return ERR_PTR(err);
err = module_enforce_rwx_sections(info->hdr, info->sechdrs,
info->secstrings, info->mod);
if (err < 0)
return ERR_PTR(err);
/* We will do a special allocation for per-cpu sections later. */
info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
/*
* Mark ro_after_init section with SHF_RO_AFTER_INIT so that
* layout_sections() can put it in the right place.
* Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set.
*/
ndx = find_sec(info, ".data..ro_after_init");
if (ndx)
info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
/*
* Mark the __jump_table section as ro_after_init as well: these data
* structures are never modified, with the exception of entries that
* refer to code in the __init section, which are annotated as such
* at module load time.
*/
ndx = find_sec(info, "__jump_table");
if (ndx)
info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
/*
* Determine total sizes, and put offsets in sh_entsize. For now
* this is done generically; there doesn't appear to be any
* special cases for the architectures.
*/
layout_sections(info->mod, info);
layout_symtab(info->mod, info);
/* Allocate and move to the final place */
err = move_module(info->mod, info);
if (err)
return ERR_PTR(err);
/* Module has been copied to its final place now: return it. */
mod = (void *)info->sechdrs[info->index.mod].sh_addr;
kmemleak_load_module(mod, info);
return mod;
}
/* mod is no longer valid after this! */
static void module_deallocate(struct module *mod, struct load_info *info)
{
percpu_modfree(mod);
module_arch_freeing_init(mod);
free_mod_mem(mod, true);
}
int __weak module_finalize(const Elf_Ehdr *hdr,
const Elf_Shdr *sechdrs,
struct module *me)
{
return 0;
}
static int post_relocation(struct module *mod, const struct load_info *info)
{
/* Sort exception table now relocations are done. */
sort_extable(mod->extable, mod->extable + mod->num_exentries);
/* Copy relocated percpu area over. */
percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
info->sechdrs[info->index.pcpu].sh_size);
/* Setup kallsyms-specific fields. */
add_kallsyms(mod, info);
/* Arch-specific module finalizing. */
return module_finalize(info->hdr, info->sechdrs, mod);
}
/* Call module constructors. */
static void do_mod_ctors(struct module *mod)
{
#ifdef CONFIG_CONSTRUCTORS
unsigned long i;
for (i = 0; i < mod->num_ctors; i++)
mod->ctors[i]();
#endif
}
/* For freeing module_init on success, in case kallsyms traversing */
struct mod_initfree {
struct llist_node node;
void *init_text;
void *init_data;
void *init_rodata;
};
static void do_free_init(struct work_struct *w)
{
struct llist_node *pos, *n, *list;
struct mod_initfree *initfree;
list = llist_del_all(&init_free_list);
synchronize_rcu();
llist_for_each_safe(pos, n, list) {
initfree = container_of(pos, struct mod_initfree, node);
execmem_free(initfree->init_text);
execmem_free(initfree->init_data);
execmem_free(initfree->init_rodata);
kfree(initfree);
}
}
void flush_module_init_free_work(void)
{
flush_work(&init_free_wq);
}
#undef MODULE_PARAM_PREFIX
#define MODULE_PARAM_PREFIX "module."
/* Default value for module->async_probe_requested */
static bool async_probe;
module_param(async_probe, bool, 0644);
/*
* This is where the real work happens.
*
* Keep it uninlined to provide a reliable breakpoint target, e.g. for the gdb
* helper command 'lx-symbols'.
*/
static noinline int do_init_module(struct module *mod)
{
int ret = 0;
struct mod_initfree *freeinit;
#if defined(CONFIG_MODULE_STATS)
unsigned int text_size = 0, total_size = 0;
for_each_mod_mem_type(type) {
const struct module_memory *mod_mem = &mod->mem[type];
if (mod_mem->size) {
total_size += mod_mem->size;
if (type == MOD_TEXT || type == MOD_INIT_TEXT)
text_size += mod_mem->size;
}
}
#endif
freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL);
if (!freeinit) {
ret = -ENOMEM;
goto fail;
}
freeinit->init_text = mod->mem[MOD_INIT_TEXT].base;
freeinit->init_data = mod->mem[MOD_INIT_DATA].base;
freeinit->init_rodata = mod->mem[MOD_INIT_RODATA].base;
do_mod_ctors(mod);
/* Start the module */
if (mod->init != NULL)
ret = do_one_initcall(mod->init);
if (ret < 0) {
goto fail_free_freeinit;
}
if (ret > 0) {
pr_warn("%s: '%s'->init suspiciously returned %d, it should "
"follow 0/-E convention\n"
"%s: loading module anyway...\n",
__func__, mod->name, ret, __func__);
dump_stack();
}
/* Now it's a first class citizen! */
mod->state = MODULE_STATE_LIVE;
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_LIVE, mod);
/* Delay uevent until module has finished its init routine */
kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
/*
* We need to finish all async code before the module init sequence
* is done. This has potential to deadlock if synchronous module
* loading is requested from async (which is not allowed!).
*
* See commit 0fdff3ec6d87 ("async, kmod: warn on synchronous
* request_module() from async workers") for more details.
*/
if (!mod->async_probe_requested)
async_synchronize_full();
ftrace_free_mem(mod, mod->mem[MOD_INIT_TEXT].base,
mod->mem[MOD_INIT_TEXT].base + mod->mem[MOD_INIT_TEXT].size);
mutex_lock(&module_mutex);
/* Drop initial reference. */
module_put(mod);
trim_init_extable(mod);
#ifdef CONFIG_KALLSYMS
/* Switch to core kallsyms now init is done: kallsyms may be walking! */
rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
#endif
ret = module_enable_rodata_ro(mod, true);
if (ret)
goto fail_mutex_unlock;
mod_tree_remove_init(mod);
module_arch_freeing_init(mod);
for_class_mod_mem_type(type, init) {
mod->mem[type].base = NULL;
mod->mem[type].size = 0;
}
#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
/* .BTF is not SHF_ALLOC and will get removed, so sanitize pointers */
mod->btf_data = NULL;
mod->btf_base_data = NULL;
#endif
/*
* We want to free module_init, but be aware that kallsyms may be
* walking this with preempt disabled. In all the failure paths, we
* call synchronize_rcu(), but we don't want to slow down the success
* path. execmem_free() cannot be called in an interrupt, so do the
* work and call synchronize_rcu() in a work queue.
*
* Note that execmem_alloc() on most architectures creates W+X page
* mappings which won't be cleaned up until do_free_init() runs. Any
* code such as mark_rodata_ro() which depends on those mappings to
* be cleaned up needs to sync with the queued work by invoking
* flush_module_init_free_work().
*/
if (llist_add(&freeinit->node, &init_free_list))
schedule_work(&init_free_wq);
mutex_unlock(&module_mutex);
wake_up_all(&module_wq);
mod_stat_add_long(text_size, &total_text_size);
mod_stat_add_long(total_size, &total_mod_size);
mod_stat_inc(&modcount);
return 0;
fail_mutex_unlock:
mutex_unlock(&module_mutex);
fail_free_freeinit:
kfree(freeinit);
fail:
/* Try to protect us from buggy refcounters. */
mod->state = MODULE_STATE_GOING;
synchronize_rcu();
module_put(mod);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
klp_module_going(mod);
ftrace_release_mod(mod);
free_module(mod);
wake_up_all(&module_wq);
return ret;
}
static int may_init_module(void)
{
if (!capable(CAP_SYS_MODULE) || modules_disabled)
return -EPERM;
return 0;
}
/* Is this module of this name done loading? No locks held. */
static bool finished_loading(const char *name)
{
struct module *mod;
bool ret;
/*
* The module_mutex should not be a heavily contended lock;
* if we get the occasional sleep here, we'll go an extra iteration
* in the wait_event_interruptible(), which is harmless.
*/
sched_annotate_sleep();
mutex_lock(&module_mutex);
mod = find_module_all(name, strlen(name), true);
ret = !mod || mod->state == MODULE_STATE_LIVE
|| mod->state == MODULE_STATE_GOING;
mutex_unlock(&module_mutex);
return ret;
}
/* Must be called with module_mutex held */
static int module_patient_check_exists(const char *name,
enum fail_dup_mod_reason reason)
{
struct module *old;
int err = 0;
old = find_module_all(name, strlen(name), true);
if (old == NULL)
return 0;
if (old->state == MODULE_STATE_COMING ||
old->state == MODULE_STATE_UNFORMED) {
/* Wait in case it fails to load. */
mutex_unlock(&module_mutex);
err = wait_event_interruptible(module_wq,
finished_loading(name));
mutex_lock(&module_mutex);
if (err)
return err;
/* The module might have gone in the meantime. */
old = find_module_all(name, strlen(name), true);
}
if (try_add_failed_module(name, reason))
pr_warn("Could not add fail-tracking for module: %s\n", name);
/*
* We are here only when the same module was being loaded. Do
* not try to load it again right now. It prevents long delays
* caused by serialized module load failures. It might happen
* when more devices of the same type trigger load of
* a particular module.
*/
if (old && old->state == MODULE_STATE_LIVE)
return -EEXIST;
return -EBUSY;
}
/*
* We try to place it in the list now to make sure it's unique before
* we dedicate too many resources. In particular, temporary percpu
* memory exhaustion.
*/
static int add_unformed_module(struct module *mod)
{
int err;
mod->state = MODULE_STATE_UNFORMED;
mutex_lock(&module_mutex);
err = module_patient_check_exists(mod->name, FAIL_DUP_MOD_LOAD);
if (err)
goto out;
mod_update_bounds(mod);
list_add_rcu(&mod->list, &modules);
mod_tree_insert(mod);
err = 0;
out:
mutex_unlock(&module_mutex);
return err;
}
static int complete_formation(struct module *mod, struct load_info *info)
{
int err;
mutex_lock(&module_mutex);
/* Find duplicate symbols (must be called under lock). */
err = verify_exported_symbols(mod);
if (err < 0)
goto out;
/* These rely on module_mutex for list integrity. */
module_bug_finalize(info->hdr, info->sechdrs, mod);
module_cfi_finalize(info->hdr, info->sechdrs, mod);
err = module_enable_rodata_ro(mod, false);
if (err)
goto out_strict_rwx;
err = module_enable_data_nx(mod);
if (err)
goto out_strict_rwx;
err = module_enable_text_rox(mod);
if (err)
goto out_strict_rwx;
/*
* Mark state as coming so strong_try_module_get() ignores us,
* but kallsyms etc. can see us.
*/
mod->state = MODULE_STATE_COMING;
mutex_unlock(&module_mutex);
return 0;
out_strict_rwx:
module_bug_cleanup(mod);
out:
mutex_unlock(&module_mutex);
return err;
}
static int prepare_coming_module(struct module *mod)
{
int err;
ftrace_module_enable(mod);
err = klp_module_coming(mod);
if (err)
return err;
err = blocking_notifier_call_chain_robust(&module_notify_list,
MODULE_STATE_COMING, MODULE_STATE_GOING, mod);
err = notifier_to_errno(err);
if (err)
klp_module_going(mod);
return err;
}
static int unknown_module_param_cb(char *param, char *val, const char *modname,
void *arg)
{
struct module *mod = arg;
int ret;
if (strcmp(param, "async_probe") == 0) {
if (kstrtobool(val, &mod->async_probe_requested))
mod->async_probe_requested = true;
return 0;
}
/* Check for magic 'dyndbg' arg */
ret = ddebug_dyndbg_module_param_cb(param, val, modname);
if (ret != 0)
pr_warn("%s: unknown parameter '%s' ignored\n", modname, param);
return 0;
}
/* Module within temporary copy, this doesn't do any allocation */
static int early_mod_check(struct load_info *info, int flags)
{
int err;
/*
* Now that we know we have the correct module name, check
* if it's blacklisted.
*/
if (blacklisted(info->name)) {
pr_err("Module %s is blacklisted\n", info->name);
return -EPERM;
}
err = rewrite_section_headers(info, flags);
if (err)
return err;
/* Check module struct version now, before we try to use module. */
if (!check_modstruct_version(info, info->mod))
return -ENOEXEC;
err = check_modinfo(info->mod, info, flags);
if (err)
return err;
mutex_lock(&module_mutex);
err = module_patient_check_exists(info->mod->name, FAIL_DUP_MOD_BECOMING);
mutex_unlock(&module_mutex);
return err;
}
/*
* Allocate and load the module: note that size of section 0 is always
* zero, and we rely on this for optional sections.
*/
static int load_module(struct load_info *info, const char __user *uargs,
int flags)
{
struct module *mod;
bool module_allocated = false;
long err = 0;
char *after_dashes;
/*
* Do the signature check (if any) first. All that
* the signature check needs is info->len, it does
* not need any of the section info. That can be
* set up later. This will minimize the chances
* of a corrupt module causing problems before
* we even get to the signature check.
*
* The check will also adjust info->len by stripping
* off the sig length at the end of the module, making
* checks against info->len more correct.
*/
err = module_sig_check(info, flags);
if (err)
goto free_copy;
/*
* Do basic sanity checks against the ELF header and
* sections. Cache useful sections and set the
* info->mod to the userspace passed struct module.
*/
err = elf_validity_cache_copy(info, flags);
if (err)
goto free_copy;
err = early_mod_check(info, flags);
if (err)
goto free_copy;
/* Figure out module layout, and allocate all the memory. */
mod = layout_and_allocate(info, flags);
if (IS_ERR(mod)) {
err = PTR_ERR(mod);
goto free_copy;
}
module_allocated = true;
audit_log_kern_module(mod->name);
/* Reserve our place in the list. */
err = add_unformed_module(mod);
if (err)
goto free_module;
/*
* We are tainting your kernel if your module gets into
* the modules linked list somehow.
*/
module_augment_kernel_taints(mod, info);
/* To avoid stressing percpu allocator, do this once we're unique. */
err = percpu_modalloc(mod, info);
if (err)
goto unlink_mod;
/* Now module is in final location, initialize linked lists, etc. */
err = module_unload_init(mod);
if (err)
goto unlink_mod;
init_param_lock(mod);
/*
* Now we've got everything in the final locations, we can
* find optional sections.
*/
err = find_module_sections(mod, info);
if (err)
goto free_unload;
err = check_export_symbol_versions(mod);
if (err)
goto free_unload;
/* Set up MODINFO_ATTR fields */
setup_modinfo(mod, info);
/* Fix up syms, so that st_value is a pointer to location. */
err = simplify_symbols(mod, info);
if (err < 0)
goto free_modinfo;
err = apply_relocations(mod, info);
if (err < 0)
goto free_modinfo;
err = post_relocation(mod, info);
if (err < 0)
goto free_modinfo;
flush_module_icache(mod);
/* Now copy in args */
mod->args = strndup_user(uargs, ~0UL >> 1);
if (IS_ERR(mod->args)) {
err = PTR_ERR(mod->args);
goto free_arch_cleanup;
}
init_build_id(mod, info);
/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
ftrace_module_init(mod);
/* Finally it's fully formed, ready to start executing. */
err = complete_formation(mod, info);
if (err)
goto ddebug_cleanup;
err = prepare_coming_module(mod);
if (err)
goto bug_cleanup;
mod->async_probe_requested = async_probe;
/* Module is ready to execute: parsing args may do that. */
after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
-32768, 32767, mod,
unknown_module_param_cb);
if (IS_ERR(after_dashes)) {
err = PTR_ERR(after_dashes);
goto coming_cleanup;
} else if (after_dashes) {
pr_warn("%s: parameters '%s' after `--' ignored\n",
mod->name, after_dashes);
}
/* Link in to sysfs. */
err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
if (err < 0)
goto coming_cleanup;
if (is_livepatch_module(mod)) {
err = copy_module_elf(mod, info);
if (err < 0)
goto sysfs_cleanup;
}
/* Get rid of temporary copy. */
free_copy(info, flags);
codetag_load_module(mod);
/* Done! */
trace_module_load(mod);
return do_init_module(mod);
sysfs_cleanup:
mod_sysfs_teardown(mod);
coming_cleanup:
mod->state = MODULE_STATE_GOING;
destroy_params(mod->kp, mod->num_kp);
blocking_notifier_call_chain(&module_notify_list,
MODULE_STATE_GOING, mod);
klp_module_going(mod);
bug_cleanup:
mod->state = MODULE_STATE_GOING;
/* module_bug_cleanup needs module_mutex protection */
mutex_lock(&module_mutex);
module_bug_cleanup(mod);
mutex_unlock(&module_mutex);
ddebug_cleanup:
ftrace_release_mod(mod);
synchronize_rcu();
kfree(mod->args);
free_arch_cleanup:
module_arch_cleanup(mod);
free_modinfo:
free_modinfo(mod);
free_unload:
module_unload_free(mod);
unlink_mod:
mutex_lock(&module_mutex);
/* Unlink carefully: kallsyms could be walking list. */
list_del_rcu(&mod->list);
mod_tree_remove(mod);
wake_up_all(&module_wq);
/* Wait for RCU-sched synchronizing before releasing mod->list. */
synchronize_rcu();
mutex_unlock(&module_mutex);
free_module:
mod_stat_bump_invalid(info, flags);
/* Free lock-classes; relies on the preceding sync_rcu() */
for_class_mod_mem_type(type, core_data) {
lockdep_free_key_range(mod->mem[type].base,
mod->mem[type].size);
}
module_deallocate(mod, info);
free_copy:
/*
* The info->len is always set. We distinguish between
* failures once the proper module was allocated and
* before that.
*/
if (!module_allocated)
mod_stat_bump_becoming(info, flags);
free_copy(info, flags);
return err;
}
SYSCALL_DEFINE3(init_module, void __user *, umod,
unsigned long, len, const char __user *, uargs)
{
int err;
struct load_info info = { };
err = may_init_module();
if (err)
return err;
pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n",
umod, len, uargs);
err = copy_module_from_user(umod, len, &info);
if (err) {
mod_stat_inc(&failed_kreads);
mod_stat_add_long(len, &invalid_kread_bytes);
return err;
}
return load_module(&info, uargs, 0);
}
struct idempotent {
const void *cookie;
struct hlist_node entry;
struct completion complete;
int ret;
};
#define IDEM_HASH_BITS 8
static struct hlist_head idem_hash[1 << IDEM_HASH_BITS];
static DEFINE_SPINLOCK(idem_lock);
static bool idempotent(struct idempotent *u, const void *cookie)
{
int hash = hash_ptr(cookie, IDEM_HASH_BITS);
struct hlist_head *head = idem_hash + hash;
struct idempotent *existing;
bool first;
u->ret = -EINTR;
u->cookie = cookie;
init_completion(&u->complete);
spin_lock(&idem_lock);
first = true;
hlist_for_each_entry(existing, head, entry) {
if (existing->cookie != cookie)
continue;
first = false;
break;
}
hlist_add_head(&u->entry, idem_hash + hash);
spin_unlock(&idem_lock);
return !first;
}
/*
* We were the first one with 'cookie' on the list, and we ended
* up completing the operation. We now need to walk the list,
* remove everybody - which includes ourselves - fill in the return
* value, and then complete the operation.
*/
static int idempotent_complete(struct idempotent *u, int ret)
{
const void *cookie = u->cookie;
int hash = hash_ptr(cookie, IDEM_HASH_BITS);
struct hlist_head *head = idem_hash + hash;
struct hlist_node *next;
struct idempotent *pos;
spin_lock(&idem_lock);
hlist_for_each_entry_safe(pos, next, head, entry) {
if (pos->cookie != cookie)
continue;
hlist_del_init(&pos->entry);
pos->ret = ret;
complete(&pos->complete);
}
spin_unlock(&idem_lock);
return ret;
}
/*
* Wait for the idempotent worker.
*
* If we get interrupted, we need to remove ourselves from the
* the idempotent list, and the completion may still come in.
*
* The 'idem_lock' protects against the race, and 'idem.ret' was
* initialized to -EINTR and is thus always the right return
* value even if the idempotent work then completes between
* the wait_for_completion and the cleanup.
*/
static int idempotent_wait_for_completion(struct idempotent *u)
{
if (wait_for_completion_interruptible(&u->complete)) {
spin_lock(&idem_lock);
if (!hlist_unhashed(&u->entry))
hlist_del(&u->entry);
spin_unlock(&idem_lock);
}
return u->ret;
}
static int init_module_from_file(struct file *f, const char __user * uargs, int flags)
{
struct load_info info = { };
void *buf = NULL;
int len;
len = kernel_read_file(f, 0, &buf, INT_MAX, NULL, READING_MODULE);
if (len < 0) {
mod_stat_inc(&failed_kreads);
return len;
}
if (flags & MODULE_INIT_COMPRESSED_FILE) {
int err = module_decompress(&info, buf, len);
vfree(buf); /* compressed data is no longer needed */
if (err) {
mod_stat_inc(&failed_decompress);
mod_stat_add_long(len, &invalid_decompress_bytes);
return err;
}
} else {
info.hdr = buf;
info.len = len;
}
return load_module(&info, uargs, flags);
}
static int idempotent_init_module(struct file *f, const char __user * uargs, int flags)
{
struct idempotent idem;
if (!f || !(f->f_mode & FMODE_READ))
return -EBADF;
/* Are we the winners of the race and get to do this? */
if (!idempotent(&idem, file_inode(f))) {
int ret = init_module_from_file(f, uargs, flags);
return idempotent_complete(&idem, ret);
}
/*
* Somebody else won the race and is loading the module.
*/
return idempotent_wait_for_completion(&idem);
}
SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
{
int err;
struct fd f;
err = may_init_module();
if (err)
return err;
pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags);
if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS
|MODULE_INIT_IGNORE_VERMAGIC
|MODULE_INIT_COMPRESSED_FILE))
return -EINVAL;
f = fdget(fd);
err = idempotent_init_module(f.file, uargs, flags);
fdput(f);
return err;
}
/* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */
char *module_flags(struct module *mod, char *buf, bool show_state)
{
int bx = 0;
BUG_ON(mod->state == MODULE_STATE_UNFORMED);
if (!mod->taints && !show_state)
goto out;
if (mod->taints ||
mod->state == MODULE_STATE_GOING ||
mod->state == MODULE_STATE_COMING) {
buf[bx++] = '(';
bx += module_flags_taint(mod->taints, buf + bx);
/* Show a - for module-is-being-unloaded */
if (mod->state == MODULE_STATE_GOING && show_state)
buf[bx++] = '-';
/* Show a + for module-is-being-loaded */
if (mod->state == MODULE_STATE_COMING && show_state)
buf[bx++] = '+';
buf[bx++] = ')';
}
out:
buf[bx] = '\0';
return buf;
}
/* Given an address, look for it in the module exception tables. */
const struct exception_table_entry *search_module_extables(unsigned long addr)
{
const struct exception_table_entry *e = NULL;
struct module *mod;
preempt_disable();
mod = __module_address(addr);
if (!mod)
goto out;
if (!mod->num_exentries)
goto out;
e = search_extable(mod->extable,
mod->num_exentries,
addr);
out:
preempt_enable();
/*
* Now, if we found one, we are running inside it now, hence
* we cannot unload the module, hence no refcnt needed.
*/
return e;
}
/**
* is_module_address() - is this address inside a module?
* @addr: the address to check.
*
* See is_module_text_address() if you simply want to see if the address
* is code (not data).
*/
bool is_module_address(unsigned long addr)
{
bool ret;
preempt_disable();
ret = __module_address(addr) != NULL;
preempt_enable();
return ret;
}
/**
* __module_address() - get the module which contains an address.
* @addr: the address.
*
* Must be called with preempt disabled or module mutex held so that
* module doesn't get freed during this.
*/
struct module *__module_address(unsigned long addr)
{
struct module *mod;
if (addr >= mod_tree.addr_min && addr <= mod_tree.addr_max)
goto lookup;
#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
if (addr >= mod_tree.data_addr_min && addr <= mod_tree.data_addr_max)
goto lookup;
#endif
return NULL;
lookup:
module_assert_mutex_or_preempt();
mod = mod_find(addr, &mod_tree);
if (mod) {
BUG_ON(!within_module(addr, mod));
if (mod->state == MODULE_STATE_UNFORMED)
mod = NULL;
}
return mod;
}
/**
* is_module_text_address() - is this address inside module code?
* @addr: the address to check.
*
* See is_module_address() if you simply want to see if the address is
* anywhere in a module. See kernel_text_address() for testing if an
* address corresponds to kernel or module code.
*/
bool is_module_text_address(unsigned long addr)
{
bool ret;
preempt_disable();
ret = __module_text_address(addr) != NULL;
preempt_enable();
return ret;
}
/**
* __module_text_address() - get the module whose code contains an address.
* @addr: the address.
*
* Must be called with preempt disabled or module mutex held so that
* module doesn't get freed during this.
*/
struct module *__module_text_address(unsigned long addr)
{
struct module *mod = __module_address(addr);
if (mod) {
/* Make sure it's within the text section. */
if (!within_module_mem_type(addr, mod, MOD_TEXT) &&
!within_module_mem_type(addr, mod, MOD_INIT_TEXT))
mod = NULL;
}
return mod;
}
/* Don't grab lock, we're oopsing. */
void print_modules(void)
{
struct module *mod;
char buf[MODULE_FLAGS_BUF_SIZE];
printk(KERN_DEFAULT "Modules linked in:");
/* Most callers should already have preempt disabled, but make sure */
preempt_disable();
list_for_each_entry_rcu(mod, &modules, list) {
if (mod->state == MODULE_STATE_UNFORMED)
continue;
pr_cont(" %s%s", mod->name, module_flags(mod, buf, true));
}
print_unloaded_tainted_modules();
preempt_enable();
if (last_unloaded_module.name[0])
pr_cont(" [last unloaded: %s%s]", last_unloaded_module.name,
last_unloaded_module.taints);
pr_cont("\n");
}
#ifdef CONFIG_MODULE_DEBUGFS
struct dentry *mod_debugfs_root;
static int module_debugfs_init(void)
{
mod_debugfs_root = debugfs_create_dir("modules", NULL);
return 0;
}
module_init(module_debugfs_init);
#endif
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