Commit c8be5424 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'modules-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux 

Pull module updates from Petr Pavlu:

 - Make .static_call_sites in modules read-only after init

   The .static_call_sites sections in modules have been made read-only
   after init to avoid any (non-)accidental modifications, similarly to
   how they are read-only after init in vmlinux

 - The rest are minor cleanups

* tag 'modules-6.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux:
  module: Remove outdated comment about text_size
  module: Make .static_call_sites read-only after init
  module: Add a separate function to mark sections as read-only after init
  module: Constify parameters of module_enforce_rwx_sections()
parents fd1f8473 a0b018a4

kernel/module/internal.h

+5 −2
Original line number Diff line number Diff line
@@ -322,8 +322,11 @@ int module_enable_rodata_ro(const struct module *mod); 
int module_enable_rodata_ro_after_init(const struct module *mod);

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);

int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,

				const char *secstrings,

				const struct module *mod);

void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs,

			       const char *secstrings);



#ifdef CONFIG_MODULE_SIG

int module_sig_check(struct load_info *info, int flags);

kernel/module/main.c

+7 −20
Original line number Diff line number Diff line
@@ -1562,12 +1562,11 @@ static void __layout_sections(struct module *mod, struct load_info *info, bool i 
{

	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

	 * { Mask of required section header flags,

	 *   Mask of excluded section header flags }

	 */

	static const unsigned long masks[][2] = {

		{ SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },

		{ SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },

		{ SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL },
@@ -2768,7 +2767,6 @@ 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.  */
@@ -2786,22 +2784,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) 
	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.

	 * Mark relevant sections as SHF_RO_AFTER_INIT so layout_sections() can

	 * put them 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;

	module_mark_ro_after_init(info->hdr, info->sechdrs, info->secstrings);



	/*

	 * Determine total sizes, and put offsets in sh_entsize.  For now

kernel/module/strict_rwx.c

+45 −2
Original line number Diff line number Diff line
@@ -87,8 +87,9 @@ int module_enable_data_nx(const struct module *mod) 
	return 0;

}



int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,

				char *secstrings, struct module *mod)

int module_enforce_rwx_sections(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,

				const char *secstrings,

				const struct module *mod)

{

	const unsigned long shf_wx = SHF_WRITE | SHF_EXECINSTR;

	int i;
@@ -106,3 +107,45 @@ int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 


	return 0;

}



static const char *const ro_after_init[] = {

	/*

	 * Section .data..ro_after_init holds data explicitly annotated by

	 * __ro_after_init.

	 */

	".data..ro_after_init",



	/*

	 * Section __jump_table holds data structures that are never modified,

	 * with the exception of entries that refer to code in the __init

	 * section, which are marked as such at module load time.

	 */

	"__jump_table",



#ifdef CONFIG_HAVE_STATIC_CALL_INLINE

	/*

	 * Section .static_call_sites holds data structures that need to be

	 * sorted and processed at module load time but are never modified

	 * afterwards.

	 */

	".static_call_sites",

#endif

};



void module_mark_ro_after_init(const Elf_Ehdr *hdr, Elf_Shdr *sechdrs,

			       const char *secstrings)

{

	int i, j;



	for (i = 1; i < hdr->e_shnum; i++) {

		Elf_Shdr *shdr = &sechdrs[i];



		for (j = 0; j < ARRAY_SIZE(ro_after_init); j++) {

			if (strcmp(secstrings + shdr->sh_name,

				   ro_after_init[j]) == 0) {

				shdr->sh_flags |= SHF_RO_AFTER_INIT;

				break;

			}

		}

	}

}