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Merge tag 'modules-6.9-rc1' of git://git.kernel.org/pub/scm/linux/ker…
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…nel/git/mcgrof/linux

Pull modules updates from Luis Chamberlain:
 "Christophe Leroy did most of the work on this release, first with a
  few cleanups on CONFIG_STRICT_KERNEL_RWX and ending with error
  handling for when set_memory_XX() can fail.

  This is part of a larger effort to clean up all these callers which
  can fail, modules is just part of it"

* tag 'modules-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux:
  module: Don't ignore errors from set_memory_XX()
  lib/test_kmod: fix kernel-doc warnings
  powerpc: Simplify strict_kernel_rwx_enabled()
  modules: Remove #ifdef CONFIG_STRICT_MODULE_RWX around rodata_enabled
  init: Declare rodata_enabled and mark_rodata_ro() at all time
  module: Change module_enable_{nx/x/ro}() to more explicit names
  module: Use set_memory_rox()
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torvalds committed Mar 13, 2024
2 parents 70ef654 + d1909c0 commit ce0c1c9
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Showing 7 changed files with 73 additions and 56 deletions.
9 changes: 1 addition & 8 deletions arch/powerpc/include/asm/mmu.h
Original file line number Diff line number Diff line change
Expand Up @@ -330,17 +330,10 @@ static __always_inline bool early_radix_enabled(void)
return early_mmu_has_feature(MMU_FTR_TYPE_RADIX);
}

#ifdef CONFIG_STRICT_KERNEL_RWX
static inline bool strict_kernel_rwx_enabled(void)
{
return rodata_enabled;
return IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) && rodata_enabled;
}
#else
static inline bool strict_kernel_rwx_enabled(void)
{
return false;
}
#endif

static inline bool strict_module_rwx_enabled(void)
{
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4 changes: 0 additions & 4 deletions include/linux/init.h
Original file line number Diff line number Diff line change
Expand Up @@ -168,12 +168,8 @@ extern initcall_entry_t __initcall_end[];

extern struct file_system_type rootfs_fs_type;

#if defined(CONFIG_STRICT_KERNEL_RWX) || defined(CONFIG_STRICT_MODULE_RWX)
extern bool rodata_enabled;
#endif
#ifdef CONFIG_STRICT_KERNEL_RWX
void mark_rodata_ro(void);
#endif

extern void (*late_time_init)(void);

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21 changes: 7 additions & 14 deletions init/main.c
Original file line number Diff line number Diff line change
Expand Up @@ -1401,10 +1401,9 @@ static int __init set_debug_rodata(char *str)
early_param("rodata", set_debug_rodata);
#endif

#ifdef CONFIG_STRICT_KERNEL_RWX
static void mark_readonly(void)
{
if (rodata_enabled) {
if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX) && rodata_enabled) {
/*
* load_module() results in W+X mappings, which are cleaned
* up with call_rcu(). Let's make sure that queued work is
Expand All @@ -1414,20 +1413,14 @@ static void mark_readonly(void)
rcu_barrier();
mark_rodata_ro();
rodata_test();
} else
} else if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
pr_info("Kernel memory protection disabled.\n");
} else if (IS_ENABLED(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)) {
pr_warn("Kernel memory protection not selected by kernel config.\n");
} else {
pr_warn("This architecture does not have kernel memory protection.\n");
}
}
#elif defined(CONFIG_ARCH_HAS_STRICT_KERNEL_RWX)
static inline void mark_readonly(void)
{
pr_warn("Kernel memory protection not selected by kernel config.\n");
}
#else
static inline void mark_readonly(void)
{
pr_warn("This architecture does not have kernel memory protection.\n");
}
#endif

void __weak free_initmem(void)
{
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6 changes: 3 additions & 3 deletions kernel/module/internal.h
Original file line number Diff line number Diff line change
Expand Up @@ -322,9 +322,9 @@ static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *
}
#endif /* CONFIG_MODULES_TREE_LOOKUP */

void module_enable_ro(const struct module *mod, bool after_init);
void module_enable_nx(const struct module *mod);
void module_enable_x(const struct module *mod);
int module_enable_rodata_ro(const struct module *mod, bool after_init);
int module_enable_data_nx(const struct module *mod);
int module_enable_text_rox(const struct module *mod);
int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
char *secstrings, struct module *mod);

Expand Down
20 changes: 16 additions & 4 deletions kernel/module/main.c
Original file line number Diff line number Diff line change
Expand Up @@ -2571,7 +2571,9 @@ static noinline int do_init_module(struct module *mod)
/* Switch to core kallsyms now init is done: kallsyms may be walking! */
rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
#endif
module_enable_ro(mod, true);
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) {
Expand Down Expand Up @@ -2609,6 +2611,8 @@ static noinline int do_init_module(struct module *mod)

return 0;

fail_mutex_unlock:
mutex_unlock(&module_mutex);
fail_free_freeinit:
kfree(freeinit);
fail:
Expand Down Expand Up @@ -2736,9 +2740,15 @@ static int complete_formation(struct module *mod, struct load_info *info)
module_bug_finalize(info->hdr, info->sechdrs, mod);
module_cfi_finalize(info->hdr, info->sechdrs, mod);

module_enable_ro(mod, false);
module_enable_nx(mod);
module_enable_x(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,
Expand All @@ -2749,6 +2759,8 @@ static int complete_formation(struct module *mod, struct load_info *info)

return 0;

out_strict_rwx:
module_bug_cleanup(mod);
out:
mutex_unlock(&module_mutex);
return err;
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63 changes: 41 additions & 22 deletions kernel/module/strict_rwx.c
Original file line number Diff line number Diff line change
Expand Up @@ -11,13 +11,16 @@
#include <linux/set_memory.h>
#include "internal.h"

static void module_set_memory(const struct module *mod, enum mod_mem_type type,
int (*set_memory)(unsigned long start, int num_pages))
static int module_set_memory(const struct module *mod, enum mod_mem_type type,
int (*set_memory)(unsigned long start, int num_pages))
{
const struct module_memory *mod_mem = &mod->mem[type];

if (!mod_mem->base)
return 0;

set_vm_flush_reset_perms(mod_mem->base);
set_memory((unsigned long)mod_mem->base, mod_mem->size >> PAGE_SHIFT);
return set_memory((unsigned long)mod_mem->base, mod_mem->size >> PAGE_SHIFT);
}

/*
Expand All @@ -26,37 +29,53 @@ static void module_set_memory(const struct module *mod, enum mod_mem_type type,
* CONFIG_STRICT_MODULE_RWX because they are needed regardless of whether we
* are strict.
*/
void module_enable_x(const struct module *mod)
int module_enable_text_rox(const struct module *mod)
{
for_class_mod_mem_type(type, text)
module_set_memory(mod, type, set_memory_x);
for_class_mod_mem_type(type, text) {
int ret;

if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
ret = module_set_memory(mod, type, set_memory_rox);
else
ret = module_set_memory(mod, type, set_memory_x);
if (ret)
return ret;
}
return 0;
}

void module_enable_ro(const struct module *mod, bool after_init)
int module_enable_rodata_ro(const struct module *mod, bool after_init)
{
if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
return;
#ifdef CONFIG_STRICT_MODULE_RWX
if (!rodata_enabled)
return;
#endif
int ret;

if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX) || !rodata_enabled)
return 0;

module_set_memory(mod, MOD_TEXT, set_memory_ro);
module_set_memory(mod, MOD_INIT_TEXT, set_memory_ro);
module_set_memory(mod, MOD_RODATA, set_memory_ro);
module_set_memory(mod, MOD_INIT_RODATA, set_memory_ro);
ret = module_set_memory(mod, MOD_RODATA, set_memory_ro);
if (ret)
return ret;
ret = module_set_memory(mod, MOD_INIT_RODATA, set_memory_ro);
if (ret)
return ret;

if (after_init)
module_set_memory(mod, MOD_RO_AFTER_INIT, set_memory_ro);
return module_set_memory(mod, MOD_RO_AFTER_INIT, set_memory_ro);

return 0;
}

void module_enable_nx(const struct module *mod)
int module_enable_data_nx(const struct module *mod)
{
if (!IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
return;
return 0;

for_class_mod_mem_type(type, data)
module_set_memory(mod, type, set_memory_nx);
for_class_mod_mem_type(type, data) {
int ret = module_set_memory(mod, type, set_memory_nx);

if (ret)
return ret;
}
return 0;
}

int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
Expand Down
6 changes: 5 additions & 1 deletion lib/test_kmod.c
Original file line number Diff line number Diff line change
Expand Up @@ -58,11 +58,14 @@ static int num_test_devs;
* @need_mod_put for your tests case.
*/
enum kmod_test_case {
/* private: */
__TEST_KMOD_INVALID = 0,
/* public: */

TEST_KMOD_DRIVER,
TEST_KMOD_FS_TYPE,

/* private: */
__TEST_KMOD_MAX,
};

Expand All @@ -82,6 +85,7 @@ struct kmod_test_device;
* @ret_sync: return value if request_module() is used, sync request for
* @TEST_KMOD_DRIVER
* @fs_sync: return value of get_fs_type() for @TEST_KMOD_FS_TYPE
* @task_sync: kthread's task_struct or %NULL if not running
* @thread_idx: thread ID
* @test_dev: test device test is being performed under
* @need_mod_put: Some tests (get_fs_type() is one) requires putting the module
Expand All @@ -108,7 +112,7 @@ struct kmod_test_device_info {
* @dev: pointer to misc_dev's own struct device
* @config_mutex: protects configuration of test
* @trigger_mutex: the test trigger can only be fired once at a time
* @thread_lock: protects @done count, and the @info per each thread
* @thread_mutex: protects @done count, and the @info per each thread
* @done: number of threads which have completed or failed
* @test_is_oom: when we run out of memory, use this to halt moving forward
* @kthreads_done: completion used to signal when all work is done
Expand Down

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