Commit d1907752 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'modules-for-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux 

Pull modules updates from Jessica Yu:
 "Summary of modules changes for the 4.19 merge window:

   - Fix modules kallsyms for livepatch. Livepatch modules can have
     SHN_UNDEF symbols in their module symbol tables for later symbol
     resolution, but kallsyms shouldn't be returning these symbols

   - Some code cleanups and minor reshuffling in load_module() were done
     to log the module name when module signature verification fails"

* tag 'modules-for-v4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  kernel/module: Use kmemdup to replace kmalloc+memcpy
  ARM: module: fix modsign build error
  modsign: log module name in the event of an error
  module: replace VMLINUX_SYMBOL_STR() with __stringify() or string literal
  module: print sensible error code
  module: setup load info before module_sig_check()
  module: make it clear when we're handling the module copy in info->hdr
  module: exclude SHN_UNDEF symbols from kallsyms api
parents 84f56852 9be936f4

arch/arm/include/asm/module.h

+1 −0
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ struct mod_arch_specific { 
#endif

};



struct module;

u32 get_module_plt(struct module *mod, unsigned long loc, Elf32_Addr val);



/*

include/linux/module.h

+2 −2
Original line number Diff line number Diff line
@@ -266,7 +266,7 @@ extern int modules_disabled; /* for sysctl */ 
/* Get/put a kernel symbol (calls must be symmetric) */

void *__symbol_get(const char *symbol);

void *__symbol_get_gpl(const char *symbol);

#define symbol_get(x) ((typeof(&x))(__symbol_get(VMLINUX_SYMBOL_STR(x))))

#define symbol_get(x) ((typeof(&x))(__symbol_get(__stringify(x))))



/* modules using other modules: kdb wants to see this. */

struct module_use {
@@ -575,7 +575,7 @@ extern void __noreturn __module_put_and_exit(struct module *mod, 
#ifdef CONFIG_MODULE_UNLOAD

int module_refcount(struct module *mod);

void __symbol_put(const char *symbol);

#define symbol_put(x) __symbol_put(VMLINUX_SYMBOL_STR(x))

#define symbol_put(x) __symbol_put(__stringify(x))

void symbol_put_addr(void *addr);



/* Sometimes we know we already have a refcount, and it's easier not

kernel/module-internal.h

+24 −1
Original line number Diff line number Diff line
@@ -9,4 +9,27 @@ 
 * 2 of the Licence, or (at your option) any later version.

 */



extern int mod_verify_sig(const void *mod, unsigned long *_modlen);
 
#include <linux/elf.h>

#include <asm/module.h>



struct load_info {

	const char *name;

	/* pointer to module in temporary copy, freed at end of load_module() */

	struct module *mod;

	Elf_Ehdr *hdr;

	unsigned long len;

	Elf_Shdr *sechdrs;

	char *secstrings, *strtab;

	unsigned long symoffs, stroffs;

	struct _ddebug *debug;

	unsigned int num_debug;

	bool sig_ok;

#ifdef CONFIG_KALLSYMS

	unsigned long mod_kallsyms_init_off;

#endif

	struct {

		unsigned int sym, str, mod, vers, info, pcpu;

	} index;

};



extern int mod_verify_sig(const void *mod, struct load_info *info);

kernel/module.c

+66 −77
Original line number Diff line number Diff line
@@ -307,24 +307,6 @@ int unregister_module_notifier(struct notifier_block *nb) 
}

EXPORT_SYMBOL(unregister_module_notifier);



struct load_info {

	const char *name;

	Elf_Ehdr *hdr;

	unsigned long len;

	Elf_Shdr *sechdrs;

	char *secstrings, *strtab;

	unsigned long symoffs, stroffs;

	struct _ddebug *debug;

	unsigned int num_debug;

	bool sig_ok;

#ifdef CONFIG_KALLSYMS

	unsigned long mod_kallsyms_init_off;

#endif

	struct {

		unsigned int sym, str, mod, vers, info, pcpu;

	} index;

};



/*

 * We require a truly strong try_module_get(): 0 means success.

 * Otherwise an error is returned due to ongoing or failed
@@ -1339,14 +1321,12 @@ static inline int check_modstruct_version(const struct load_info *info, 
	 * locking is necessary -- use preempt_disable() to placate lockdep.

	 */

	preempt_disable();

	if (!find_symbol(VMLINUX_SYMBOL_STR(module_layout), NULL,

			 &crc, true, false)) {

	if (!find_symbol("module_layout", NULL, &crc, true, false)) {

		preempt_enable();

		BUG();

	}

	preempt_enable();

	return check_version(info, VMLINUX_SYMBOL_STR(module_layout),

			     mod, crc);

	return check_version(info, "module_layout", mod, crc);

}



/* First part is kernel version, which we ignore if module has crcs. */
@@ -2059,21 +2039,19 @@ static int copy_module_elf(struct module *mod, struct load_info *info) 


	/* Elf section header table */

	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;

	mod->klp_info->sechdrs = kmalloc(size, GFP_KERNEL);

	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);

	if (mod->klp_info->sechdrs == NULL) {

		ret = -ENOMEM;

		goto free_info;

	}

	memcpy(mod->klp_info->sechdrs, info->sechdrs, size);



	/* Elf section name string table */

	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;

	mod->klp_info->secstrings = kmalloc(size, GFP_KERNEL);

	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);

	if (mod->klp_info->secstrings == NULL) {

		ret = -ENOMEM;

		goto free_sechdrs;

	}

	memcpy(mod->klp_info->secstrings, info->secstrings, size);



	/* Elf symbol section index */

	symndx = info->index.sym;
@@ -2282,9 +2260,9 @@ static int simplify_symbols(struct module *mod, const struct load_info *info) 
			if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)

				break;



			pr_warn("%s: Unknown symbol %s (err %li)\n",

				mod->name, name, PTR_ERR(ksym));

			ret = PTR_ERR(ksym) ?: -ENOENT;

			pr_warn("%s: Unknown symbol %s (err %d)\n",

				mod->name, name, ret);

			break;



		default:
@@ -2486,7 +2464,11 @@ static char *get_modinfo(struct load_info *info, const char *tag) 
	Elf_Shdr *infosec = &info->sechdrs[info->index.info];

	unsigned long size = infosec->sh_size;



	for (p = (char *)infosec->sh_addr; p; p = next_string(p, &size)) {

	/*

	 * get_modinfo() calls made before rewrite_section_headers()

	 * must use sh_offset, as sh_addr isn't set!

	 */

	for (p = (char *)info->hdr + infosec->sh_offset; p; p = next_string(p, &size)) {

		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')

			return p + taglen + 1;

	}
@@ -2774,7 +2756,7 @@ static int module_sig_check(struct load_info *info, int flags) 
	    memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {

		/* We truncate the module to discard the signature */

		info->len -= markerlen;

		err = mod_verify_sig(mod, &info->len);

		err = mod_verify_sig(mod, info);

	}



	if (!err) {
@@ -2926,17 +2908,7 @@ static int rewrite_section_headers(struct load_info *info, int flags) 
	}



	/* Track but don't keep modinfo and version sections. */

	if (flags & MODULE_INIT_IGNORE_MODVERSIONS)

		info->index.vers = 0; /* Pretend no __versions section! */

	else

		info->index.vers = find_sec(info, "__versions");

	info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;



	info->index.info = find_sec(info, ".modinfo");

	if (!info->index.info)

		info->name = "(missing .modinfo section)";

	else

		info->name = get_modinfo(info, "name");

	info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;



	return 0;
@@ -2947,23 +2919,24 @@ static int rewrite_section_headers(struct load_info *info, int flags) 
 * search for module section index etc), and do some basic section

 * verification.

 *

 * Return the temporary module pointer (we'll replace it with the final

 * one when we move the module sections around).

 * Set info->mod to the temporary copy of the module in info->hdr. The final one

 * will be allocated in move_module().

 */

static struct module *setup_load_info(struct load_info *info, int flags)

static int setup_load_info(struct load_info *info, int flags)

{

	unsigned int i;

	int err;

	struct module *mod;



	/* Set up the convenience variables */

	info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;

	info->secstrings = (void *)info->hdr

		+ info->sechdrs[info->hdr->e_shstrndx].sh_offset;



	err = rewrite_section_headers(info, flags);

	if (err)

		return ERR_PTR(err);

	/* Try to find a name early so we can log errors with a module name */

	info->index.info = find_sec(info, ".modinfo");

	if (!info->index.info)

		info->name = "(missing .modinfo section)";

	else

		info->name = get_modinfo(info, "name");



	/* Find internal symbols and strings. */

	for (i = 1; i < info->hdr->e_shnum; i++) {
@@ -2976,34 +2949,35 @@ static struct module *setup_load_info(struct load_info *info, int flags) 
		}

	}



	if (info->index.sym == 0) {

		pr_warn("%s: module has no symbols (stripped?)\n", info->name);

		return -ENOEXEC;

	}



	info->index.mod = find_sec(info, ".gnu.linkonce.this_module");

	if (!info->index.mod) {

		pr_warn("%s: No module found in object\n",

			info->name ?: "(missing .modinfo name field)");

		return ERR_PTR(-ENOEXEC);

		return -ENOEXEC;

	}

	/* This is temporary: point mod into copy of data. */

	mod = (void *)info->sechdrs[info->index.mod].sh_addr;

	info->mod = (void *)info->hdr + info->sechdrs[info->index.mod].sh_offset;



	/*

	 * If we didn't load the .modinfo 'name' field, fall back to

	 * If we didn't load the .modinfo 'name' field earlier, fall back to

	 * on-disk struct mod 'name' field.

	 */

	if (!info->name)

		info->name = mod->name;

		info->name = info->mod->name;



	if (info->index.sym == 0) {

		pr_warn("%s: module has no symbols (stripped?)\n", info->name);

		return ERR_PTR(-ENOEXEC);

	}

	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);



	/* Check module struct version now, before we try to use module. */

	if (!check_modstruct_version(info, mod))

		return ERR_PTR(-ENOEXEC);



	return mod;

	return 0;

}



static int check_modinfo(struct module *mod, struct load_info *info, int flags)
@@ -3298,25 +3272,17 @@ core_param(module_blacklist, module_blacklist, charp, 0400); 


static struct module *layout_and_allocate(struct load_info *info, int flags)

{

	/* Module within temporary copy. */

	struct module *mod;

	unsigned int ndx;

	int err;



	mod = setup_load_info(info, flags);

	if (IS_ERR(mod))

		return mod;



	if (blacklisted(info->name))

		return ERR_PTR(-EPERM);



	err = check_modinfo(mod, info, flags);

	err = check_modinfo(info->mod, info, flags);

	if (err)

		return ERR_PTR(err);



	/* Allow arches to frob section contents and sizes.  */

	err = module_frob_arch_sections(info->hdr, info->sechdrs,

					info->secstrings, mod);

					info->secstrings, info->mod);

	if (err < 0)

		return ERR_PTR(err);
@@ -3335,11 +3301,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags) 
	/* 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(mod, info);

	layout_symtab(mod, info);

	layout_sections(info->mod, info);

	layout_symtab(info->mod, info);



	/* Allocate and move to the final place */

	err = move_module(mod, info);

	err = move_module(info->mod, info);

	if (err)

		return ERR_PTR(err);
@@ -3657,17 +3623,36 @@ static int load_module(struct load_info *info, const char __user *uargs, 
		       int flags)

{

	struct module *mod;

	long err;

	long err = 0;

	char *after_dashes;



	err = elf_header_check(info);

	if (err)

		goto free_copy;



	err = setup_load_info(info, flags);

	if (err)

		goto free_copy;



	if (blacklisted(info->name)) {

		err = -EPERM;

		goto free_copy;

	}



	err = module_sig_check(info, flags);

	if (err)

		goto free_copy;



	err = elf_header_check(info);

	err = rewrite_section_headers(info, flags);

	if (err)

		goto free_copy;



	/* Check module struct version now, before we try to use module. */

	if (!check_modstruct_version(info, info->mod)) {

		err = -ENOEXEC;

		goto free_copy;

	}



	/* Figure out module layout, and allocate all the memory. */

	mod = layout_and_allocate(info, flags);

	if (IS_ERR(mod)) {
@@ -4067,7 +4052,7 @@ static unsigned long mod_find_symname(struct module *mod, const char *name) 


	for (i = 0; i < kallsyms->num_symtab; i++)

		if (strcmp(name, symname(kallsyms, i)) == 0 &&

		    kallsyms->symtab[i].st_info != 'U')

		    kallsyms->symtab[i].st_shndx != SHN_UNDEF)

			return kallsyms->symtab[i].st_value;

	return 0;

}
@@ -4113,6 +4098,10 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *, 
		if (mod->state == MODULE_STATE_UNFORMED)

			continue;

		for (i = 0; i < kallsyms->num_symtab; i++) {



			if (kallsyms->symtab[i].st_shndx == SHN_UNDEF)

				continue;



			ret = fn(data, symname(kallsyms, i),

				 mod, kallsyms->symtab[i].st_value);

			if (ret != 0)

kernel/module_signing.c

+7 −5
Original line number Diff line number Diff line
@@ -45,10 +45,10 @@ struct module_signature { 
/*

 * Verify the signature on a module.

 */

int mod_verify_sig(const void *mod, unsigned long *_modlen)

int mod_verify_sig(const void *mod, struct load_info *info)

{

	struct module_signature ms;

	size_t modlen = *_modlen, sig_len;

	size_t sig_len, modlen = info->len;



	pr_devel("==>%s(,%zu)\n", __func__, modlen);
@@ -62,10 +62,11 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen) 
	if (sig_len >= modlen)

		return -EBADMSG;

	modlen -= sig_len;

	*_modlen = modlen;

	info->len = modlen;



	if (ms.id_type != PKEY_ID_PKCS7) {

		pr_err("Module is not signed with expected PKCS#7 message\n");

		pr_err("%s: Module is not signed with expected PKCS#7 message\n",

		       info->name);

		return -ENOPKG;

	}
@@ -76,7 +77,8 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen) 
	    ms.__pad[0] != 0 ||

	    ms.__pad[1] != 0 ||

	    ms.__pad[2] != 0) {

		pr_err("PKCS#7 signature info has unexpected non-zero params\n");

		pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n",

		       info->name);

		return -EBADMSG;

	}

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