1 files changed, 245 insertions, 236 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 4bf30e4b3eaa..30479355ab85 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -87,8 +87,7 @@
  * 3) module_addr_min/module_addr_max.
  * (delete and add uses RCU list operations).
  */
-DEFINE_MUTEX(module_mutex);
-EXPORT_SYMBOL_GPL(module_mutex);
+static DEFINE_MUTEX(module_mutex);
 static LIST_HEAD(modules);
 
 /* Work queue for freeing init sections in success case */
@@ -256,11 +255,6 @@ static void mod_update_bounds(struct module *mod)
 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 #endif /* CONFIG_KGDB_KDB */
 
-static void module_assert_mutex(void)
-{
-	lockdep_assert_held(&module_mutex);
-}
-
 static void module_assert_mutex_or_preempt(void)
 {
 #ifdef CONFIG_LOCKDEP
@@ -414,19 +408,8 @@ extern const struct kernel_symbol __start___ksymtab[];
 extern const struct kernel_symbol __stop___ksymtab[];
 extern const struct kernel_symbol __start___ksymtab_gpl[];
 extern const struct kernel_symbol __stop___ksymtab_gpl[];
-extern const struct kernel_symbol __start___ksymtab_gpl_future[];
-extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
 extern const s32 __start___kcrctab[];
 extern const s32 __start___kcrctab_gpl[];
-extern const s32 __start___kcrctab_gpl_future[];
-#ifdef CONFIG_UNUSED_SYMBOLS
-extern const struct kernel_symbol __start___ksymtab_unused[];
-extern const struct kernel_symbol __stop___ksymtab_unused[];
-extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
-extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
-extern const s32 __start___kcrctab_unused[];
-extern const s32 __start___kcrctab_unused_gpl[];
-#endif
 
 #ifndef CONFIG_MODVERSIONS
 #define symversion(base, idx) NULL
@@ -434,87 +417,14 @@ extern const s32 __start___kcrctab_unused_gpl[];
 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
 #endif
 
-static bool each_symbol_in_section(const struct symsearch *arr,
-				   unsigned int arrsize,
-				   struct module *owner,
-				   bool (*fn)(const struct symsearch *syms,
-					      struct module *owner,
-					      void *data),
-				   void *data)
-{
-	unsigned int j;
-
-	for (j = 0; j < arrsize; j++) {
-		if (fn(&arr[j], owner, data))
-			return true;
-	}
-
-	return false;
-}
-
-/* Returns true as soon as fn returns true, otherwise false. */
-static bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
-				    struct module *owner,
-				    void *data),
-			 void *data)
-{
-	struct module *mod;
-	static const struct symsearch arr[] = {
-		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
-		  NOT_GPL_ONLY, false },
-		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
-		  __start___kcrctab_gpl,
-		  GPL_ONLY, false },
-		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
-		  __start___kcrctab_gpl_future,
-		  WILL_BE_GPL_ONLY, false },
-#ifdef CONFIG_UNUSED_SYMBOLS
-		{ __start___ksymtab_unused, __stop___ksymtab_unused,
-		  __start___kcrctab_unused,
-		  NOT_GPL_ONLY, true },
-		{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
-		  __start___kcrctab_unused_gpl,
-		  GPL_ONLY, true },
-#endif
-	};
-
-	module_assert_mutex_or_preempt();
-
-	if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
-		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, false },
-			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
-			  mod->gpl_crcs,
-			  GPL_ONLY, false },
-			{ mod->gpl_future_syms,
-			  mod->gpl_future_syms + mod->num_gpl_future_syms,
-			  mod->gpl_future_crcs,
-			  WILL_BE_GPL_ONLY, false },
-#ifdef CONFIG_UNUSED_SYMBOLS
-			{ mod->unused_syms,
-			  mod->unused_syms + mod->num_unused_syms,
-			  mod->unused_crcs,
-			  NOT_GPL_ONLY, true },
-			{ mod->unused_gpl_syms,
-			  mod->unused_gpl_syms + mod->num_unused_gpl_syms,
-			  mod->unused_gpl_crcs,
-			  GPL_ONLY, true },
-#endif
-		};
-
-		if (mod->state == MODULE_STATE_UNFORMED)
-			continue;
-
-		if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
-			return true;
-	}
-	return false;
-}
+struct symsearch {
+	const struct kernel_symbol *start, *stop;
+	const s32 *crcs;
+	enum mod_license {
+		NOT_GPL_ONLY,
+		GPL_ONLY,
+	} license;
+};
 
 struct find_symbol_arg {
 	/* Input */
@@ -535,28 +445,8 @@ static bool check_exported_symbol(const struct symsearch *syms,
 {
 	struct find_symbol_arg *fsa = data;
 
-	if (!fsa->gplok) {
-		if (syms->license == GPL_ONLY)
-			return false;
-		if (syms->license == WILL_BE_GPL_ONLY && fsa->warn) {
-			pr_warn("Symbol %s is being used by a non-GPL module, "
-				"which will not be allowed in the future\n",
-				fsa->name);
-		}
-	}
-
-#ifdef CONFIG_UNUSED_SYMBOLS
-	if (syms->unused && fsa->warn) {
-		pr_warn("Symbol %s is marked as UNUSED, however this module is "
-			"using it.\n", fsa->name);
-		pr_warn("This symbol will go away in the future.\n");
-		pr_warn("Please evaluate if this is the right api to use and "
-			"if it really is, submit a report to the linux kernel "
-			"mailing list together with submitting your code for "
-			"inclusion.\n");
-	}
-#endif
-
+	if (!fsa->gplok && syms->license == GPL_ONLY)
+		return false;
 	fsa->owner = owner;
 	fsa->crc = symversion(syms->crcs, symnum);
 	fsa->sym = &syms->start[symnum];
@@ -619,31 +509,44 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms,
  * Find an exported symbol and return it, along with, (optional) crc and
  * (optional) module which owns it.  Needs preempt disabled or module_mutex.
  */
-static const struct kernel_symbol *find_symbol(const char *name,
-					struct module **owner,
-					const s32 **crc,
-					enum mod_license *license,
-					bool gplok,
-					bool warn)
-{
-	struct find_symbol_arg fsa;
-
-	fsa.name = name;
-	fsa.gplok = gplok;
-	fsa.warn = warn;
-
-	if (each_symbol_section(find_exported_symbol_in_section, &fsa)) {
-		if (owner)
-			*owner = fsa.owner;
-		if (crc)
-			*crc = fsa.crc;
-		if (license)
-			*license = fsa.license;
-		return fsa.sym;
+static 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", name);
-	return NULL;
+	pr_debug("Failed to find symbol %s\n", fsa->name);
+	return false;
 }
 
 /*
@@ -669,10 +572,8 @@ static struct module *find_module_all(const char *name, size_t len,
 
 struct module *find_module(const char *name)
 {
-	module_assert_mutex();
 	return find_module_all(name, strlen(name), false);
 }
-EXPORT_SYMBOL_GPL(find_module);
 
 #ifdef CONFIG_SMP
 
@@ -1107,12 +1008,15 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod)
 
 void __symbol_put(const char *symbol)
 {
-	struct module *owner;
+	struct find_symbol_arg fsa = {
+		.name	= symbol,
+		.gplok	= true,
+	};
 
 	preempt_disable();
-	if (!find_symbol(symbol, &owner, NULL, NULL, true, false))
+	if (!find_symbol(&fsa))
 		BUG();
-	module_put(owner);
+	module_put(fsa.owner);
 	preempt_enable();
 }
 EXPORT_SYMBOL(__symbol_put);
@@ -1381,19 +1285,22 @@ bad_version:
 static inline int check_modstruct_version(const struct load_info *info,
 					  struct module *mod)
 {
-	const s32 *crc;
+	struct find_symbol_arg fsa = {
+		.name	= "module_layout",
+		.gplok	= true,
+	};
 
 	/*
 	 * Since this should be found in kernel (which can't be removed), no
 	 * locking is necessary -- use preempt_disable() to placate lockdep.
 	 */
 	preempt_disable();
-	if (!find_symbol("module_layout", NULL, &crc, NULL, true, false)) {
+	if (!find_symbol(&fsa)) {
 		preempt_enable();
 		BUG();
 	}
 	preempt_enable();
-	return check_version(info, "module_layout", mod, crc);
+	return check_version(info, "module_layout", mod, fsa.crc);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */
@@ -1487,10 +1394,11 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 						  const char *name,
 						  char ownername[])
 {
-	struct module *owner;
-	const struct kernel_symbol *sym;
-	const s32 *crc;
-	enum mod_license license;
+	struct find_symbol_arg fsa = {
+		.name	= name,
+		.gplok	= !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
+		.warn	= true,
+	};
 	int err;
 
 	/*
@@ -1500,42 +1408,40 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 	 */
 	sched_annotate_sleep();
 	mutex_lock(&module_mutex);
-	sym = find_symbol(name, &owner, &crc, &license,
-			  !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
-	if (!sym)
+	if (!find_symbol(&fsa))
 		goto unlock;
 
-	if (license == GPL_ONLY)
+	if (fsa.license == GPL_ONLY)
 		mod->using_gplonly_symbols = true;
 
-	if (!inherit_taint(mod, owner)) {
-		sym = NULL;
+	if (!inherit_taint(mod, fsa.owner)) {
+		fsa.sym = NULL;
 		goto getname;
 	}
 
-	if (!check_version(info, name, mod, crc)) {
-		sym = ERR_PTR(-EINVAL);
+	if (!check_version(info, name, mod, fsa.crc)) {
+		fsa.sym = ERR_PTR(-EINVAL);
 		goto getname;
 	}
 
-	err = verify_namespace_is_imported(info, sym, mod);
+	err = verify_namespace_is_imported(info, fsa.sym, mod);
 	if (err) {
-		sym = ERR_PTR(err);
+		fsa.sym = ERR_PTR(err);
 		goto getname;
 	}
 
-	err = ref_module(mod, owner);
+	err = ref_module(mod, fsa.owner);
 	if (err) {
-		sym = ERR_PTR(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(owner), MODULE_NAME_LEN);
+	strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
 unlock:
 	mutex_unlock(&module_mutex);
-	return sym;
+	return fsa.sym;
 }
 
 static const struct kernel_symbol *
@@ -2296,16 +2202,19 @@ static void free_module(struct module *mod)
 
 void *__symbol_get(const char *symbol)
 {
-	struct module *owner;
-	const struct kernel_symbol *sym;
+	struct find_symbol_arg fsa = {
+		.name	= symbol,
+		.gplok	= true,
+		.warn	= true,
+	};
 
 	preempt_disable();
-	sym = find_symbol(symbol, &owner, NULL, NULL, true, true);
-	if (sym && strong_try_module_get(owner))
-		sym = NULL;
+	if (!find_symbol(&fsa) || strong_try_module_get(fsa.owner)) {
+		preempt_enable();
+		return NULL;
+	}
 	preempt_enable();
-
-	return sym ? (void *)kernel_symbol_value(sym) : NULL;
+	return (void *)kernel_symbol_value(fsa.sym);
 }
 EXPORT_SYMBOL_GPL(__symbol_get);
 
@@ -2318,7 +2227,6 @@ EXPORT_SYMBOL_GPL(__symbol_get);
 static int verify_exported_symbols(struct module *mod)
 {
 	unsigned int i;
-	struct module *owner;
 	const struct kernel_symbol *s;
 	struct {
 		const struct kernel_symbol *sym;
@@ -2326,21 +2234,19 @@ static int verify_exported_symbols(struct module *mod)
 	} arr[] = {
 		{ mod->syms, mod->num_syms },
 		{ mod->gpl_syms, mod->num_gpl_syms },
-		{ mod->gpl_future_syms, mod->num_gpl_future_syms },
-#ifdef CONFIG_UNUSED_SYMBOLS
-		{ mod->unused_syms, mod->num_unused_syms },
-		{ mod->unused_gpl_syms, mod->num_unused_gpl_syms },
-#endif
 	};
 
 	for (i = 0; i < ARRAY_SIZE(arr); i++) {
 		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
-			if (find_symbol(kernel_symbol_name(s), &owner, NULL,
-					NULL, true, false)) {
+			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(owner));
+				       module_name(fsa.owner));
 				return -ENOEXEC;
 			}
 		}
@@ -2348,6 +2254,21 @@ static int verify_exported_symbols(struct module *mod)
 	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)
 {
@@ -2395,8 +2316,10 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)
 				break;
 			}
 
-			/* Ok if weak.  */
-			if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
+			/* 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;
@@ -2964,7 +2887,7 @@ static int module_sig_check(struct load_info *info, int flags)
 	}
 
 	if (is_module_sig_enforced()) {
-		pr_notice("%s: loading of %s is rejected\n", info->name, reason);
+		pr_notice("Loading of %s is rejected\n", reason);
 		return -EKEYREJECTED;
 	}
 
@@ -2977,9 +2900,33 @@ static int module_sig_check(struct load_info *info, int flags)
 }
 #endif /* !CONFIG_MODULE_SIG */
 
-/* Sanity checks against invalid binaries, wrong arch, weird elf version. */
-static int elf_header_check(struct load_info *info)
+static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr)
+{
+	unsigned long secend;
+
+	/*
+	 * 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;
+}
+
+/*
+ * Sanity checks against invalid binaries, wrong arch, weird elf version.
+ *
+ * Also do basic validity checks against section offsets and sizes, the
+ * section name string table, and the indices used for it (sh_name).
+ */
+static int elf_validity_check(struct load_info *info)
 {
+	unsigned int i;
+	Elf_Shdr *shdr, *strhdr;
+	int err;
+
 	if (info->len < sizeof(*(info->hdr)))
 		return -ENOEXEC;
 
@@ -2989,11 +2936,78 @@ static int elf_header_check(struct load_info *info)
 	    || info->hdr->e_shentsize != sizeof(Elf_Shdr))
 		return -ENOEXEC;
 
+	/*
+	 * 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))
 		return -ENOEXEC;
 
+	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)
+		return -ENOEXEC;
+
+	strhdr = &info->sechdrs[info->hdr->e_shstrndx];
+	err = validate_section_offset(info, strhdr);
+	if (err < 0)
+		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 (info->secstrings[strhdr->sh_size - 1] != '\0')
+		return -ENOEXEC;
+
+	/*
+	 * 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)
+		return -ENOEXEC;
+
+	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)
+				return -ENOEXEC;
+			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 (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;
+		}
+	}
+
 	return 0;
 }
 
@@ -3095,11 +3109,6 @@ static int rewrite_section_headers(struct load_info *info, int flags)
 
 	for (i = 1; i < info->hdr->e_shnum; i++) {
 		Elf_Shdr *shdr = &info->sechdrs[i];
-		if (shdr->sh_type != SHT_NOBITS
-		    && info->len < shdr->sh_offset + shdr->sh_size) {
-			pr_err("Module len %lu truncated\n", info->len);
-			return -ENOEXEC;
-		}
 
 		/*
 		 * Mark all sections sh_addr with their address in the
@@ -3133,11 +3142,6 @@ static int setup_load_info(struct load_info *info, int flags)
 {
 	unsigned int i;
 
-	/* 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;
-
 	/* 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)
@@ -3241,22 +3245,7 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 				     sizeof(*mod->gpl_syms),
 				     &mod->num_gpl_syms);
 	mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
-	mod->gpl_future_syms = section_objs(info,
-					    "__ksymtab_gpl_future",
-					    sizeof(*mod->gpl_future_syms),
-					    &mod->num_gpl_future_syms);
-	mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future");
-
-#ifdef CONFIG_UNUSED_SYMBOLS
-	mod->unused_syms = section_objs(info, "__ksymtab_unused",
-					sizeof(*mod->unused_syms),
-					&mod->num_unused_syms);
-	mod->unused_crcs = section_addr(info, "__kcrctab_unused");
-	mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl",
-					    sizeof(*mod->unused_gpl_syms),
-					    &mod->num_unused_gpl_syms);
-	mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl");
-#endif
+
 #ifdef CONFIG_CONSTRUCTORS
 	mod->ctors = section_objs(info, ".ctors",
 				  sizeof(*mod->ctors), &mod->num_ctors);
@@ -3437,14 +3426,8 @@ static int check_module_license_and_versions(struct module *mod)
 		pr_warn("%s: module license taints kernel.\n", mod->name);
 
 #ifdef CONFIG_MODVERSIONS
-	if ((mod->num_syms && !mod->crcs)
-	    || (mod->num_gpl_syms && !mod->gpl_crcs)
-	    || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
-#ifdef CONFIG_UNUSED_SYMBOLS
-	    || (mod->num_unused_syms && !mod->unused_crcs)
-	    || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
-#endif
-		) {
+	if ((mod->num_syms && !mod->crcs) ||
+	    (mod->num_gpl_syms && !mod->gpl_crcs)) {
 		return try_to_force_load(mod,
 					 "no versions for exported symbols");
 	}
@@ -3894,26 +3877,50 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	long err = 0;
 	char *after_dashes;
 
-	err = elf_header_check(info);
+	/*
+	 * 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.
+	 */
+	err = elf_validity_check(info);
 	if (err) {
-		pr_err("Module has invalid ELF header\n");
+		pr_err("Module has invalid ELF structures\n");
 		goto free_copy;
 	}
 
+	/*
+	 * Everything checks out, so set up the section info
+	 * in the info structure.
+	 */
 	err = setup_load_info(info, flags);
 	if (err)
 		goto free_copy;
 
+	/*
+	 * Now that we know we have the correct module name, check
+	 * if it's blacklisted.
+	 */
 	if (blacklisted(info->name)) {
 		err = -EPERM;
 		pr_err("Module %s is blacklisted\n", info->name);
 		goto free_copy;
 	}
 
-	err = module_sig_check(info, flags);
-	if (err)
-		goto free_copy;
-
 	err = rewrite_section_headers(info, flags);
 	if (err)
 		goto free_copy;
@@ -4374,16 +4381,16 @@ unsigned long module_kallsyms_lookup_name(const char *name)
 	return ret;
 }
 
+#ifdef CONFIG_LIVEPATCH
 int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 					     struct module *, unsigned long),
 				   void *data)
 {
 	struct module *mod;
 	unsigned int i;
-	int ret;
-
-	module_assert_mutex();
+	int ret = 0;
 
+	mutex_lock(&module_mutex);
 	list_for_each_entry(mod, &modules, list) {
 		/* We hold module_mutex: no need for rcu_dereference_sched */
 		struct mod_kallsyms *kallsyms = mod->kallsyms;
@@ -4399,11 +4406,13 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
 				 mod, kallsyms_symbol_value(sym));
 			if (ret != 0)
-				return ret;
+				break;
 		}
 	}
-	return 0;
+	mutex_unlock(&module_mutex);
+	return ret;
 }
+#endif /* CONFIG_LIVEPATCH */
 #endif /* CONFIG_KALLSYMS */
 
 /* Maximum number of characters written by module_flags() */