Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module updates from Rusty Russell:
 "The only interesting thing here is Jessica's patch to add
  ro_after_init support to modules.  The rest are all trivia"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  extable.h: add stddef.h so "NULL" definition is not implicit
  modules: add ro_after_init support
  jump_label: disable preemption around __module_text_address().
  exceptions: fork exception table content from module.h into extable.h
  modules: Add kernel parameter to blacklist modules
  module: Do a WARN_ON_ONCE() for assert module mutex not held
  Documentation/module-signing.txt: Note need for version info if reusing a key
  module: Invalidate signatures on force-loaded modules
  module: Issue warnings when tainting kernel
  module: fix redundant test.
  module: fix noreturn attribute for __module_put_and_exit()

8 files changed, 155 insertions, 52 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 00e4c2f..1a855d0 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2320,6 +2320,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Note that if CONFIG_MODULE_SIG_FORCE is set, that
 			is always true, so this option does nothing.
 
+	module_blacklist=  [KNL] Do not load a comma-separated list of
+			modules.  Useful for debugging problem modules.
+
 	mousedev.tap_time=
 			[MOUSE] Maximum time between finger touching and
 			leaving touchpad surface for touch to be considered
diff --git a/Documentation/module-signing.txt b/Documentation/module-signing.txt
index 696d5ca..f0e3361 100644
--- a/Documentation/module-signing.txt
+++ b/Documentation/module-signing.txt
@@ -271,3 +271,9 @@ Since the private key is used to sign modules, viruses and malware could use
 the private key to sign modules and compromise the operating system.  The
 private key must be either destroyed or moved to a secure location and not kept
 in the root node of the kernel source tree.
+
+If you use the same private key to sign modules for multiple kernel
+configurations, you must ensure that the module version information is
+sufficient to prevent loading a module into a different kernel.  Either
+set CONFIG_MODVERSIONS=y or ensure that each configuration has a different
+kernel release string by changing EXTRAVERSION or CONFIG_LOCALVERSION.
diff --git a/include/linux/extable.h b/include/linux/extable.h
new file mode 100644
index 0000000..7effea4
--- /dev/null
+++ b/include/linux/extable.h
@@ -0,0 +1,32 @@
+#ifndef _LINUX_EXTABLE_H
+#define _LINUX_EXTABLE_H
+
+#include <linux/stddef.h>	/* for NULL */
+
+struct module;
+struct exception_table_entry;
+
+const struct exception_table_entry *
+search_extable(const struct exception_table_entry *first,
+	       const struct exception_table_entry *last,
+	       unsigned long value);
+void sort_extable(struct exception_table_entry *start,
+		  struct exception_table_entry *finish);
+void sort_main_extable(void);
+void trim_init_extable(struct module *m);
+
+/* Given an address, look for it in the exception tables */
+const struct exception_table_entry *search_exception_tables(unsigned long add);
+
+#ifdef CONFIG_MODULES
+/* For extable.c to search modules' exception tables. */
+const struct exception_table_entry *search_module_extables(unsigned long addr);
+#else
+static inline const struct exception_table_entry *
+search_module_extables(unsigned long addr)
+{
+	return NULL;
+}
+#endif /*CONFIG_MODULES*/
+
+#endif /* _LINUX_EXTABLE_H */
diff --git a/include/linux/module.h b/include/linux/module.h
index 3daf2b3..0c3207d 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -18,6 +18,7 @@
 #include <linux/moduleparam.h>
 #include <linux/jump_label.h>
 #include <linux/export.h>
+#include <linux/extable.h>	/* only as arch move module.h -> extable.h */
 #include <linux/rbtree_latch.h>
 
 #include <linux/percpu.h>
@@ -37,6 +38,7 @@ struct modversion_info {
 };
 
 struct module;
+struct exception_table_entry;
 
 struct module_kobject {
 	struct kobject kobj;
@@ -155,18 +157,6 @@ extern void cleanup_module(void);
 #define __INITRODATA_OR_MODULE __INITRODATA
 #endif /*CONFIG_MODULES*/
 
-/* Archs provide a method of finding the correct exception table. */
-struct exception_table_entry;
-
-const struct exception_table_entry *
-search_extable(const struct exception_table_entry *first,
-	       const struct exception_table_entry *last,
-	       unsigned long value);
-void sort_extable(struct exception_table_entry *start,
-		  struct exception_table_entry *finish);
-void sort_main_extable(void);
-void trim_init_extable(struct module *m);
-
 /* Generic info of form tag = "info" */
 #define MODULE_INFO(tag, info) __MODULE_INFO(tag, tag, info)
 
@@ -268,9 +258,6 @@ extern const typeof(name) __mod_##type##__##name##_device_table		\
  * files require multiple MODULE_FIRMWARE() specifiers */
 #define MODULE_FIRMWARE(_firmware) MODULE_INFO(firmware, _firmware)
 
-/* Given an address, look for it in the exception tables */
-const struct exception_table_entry *search_exception_tables(unsigned long add);
-
 struct notifier_block;
 
 #ifdef CONFIG_MODULES
@@ -311,6 +298,8 @@ struct module_layout {
 	unsigned int text_size;
 	/* Size of RO section of the module (text+rodata) */
 	unsigned int ro_size;
+	/* Size of RO after init section */
+	unsigned int ro_after_init_size;
 
 #ifdef CONFIG_MODULES_TREE_LOOKUP
 	struct mod_tree_node mtn;
@@ -575,8 +564,8 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 					     struct module *, unsigned long),
 				   void *data);
 
-extern void __module_put_and_exit(struct module *mod, long code)
-	__attribute__((noreturn));
+extern void __noreturn __module_put_and_exit(struct module *mod,
+			long code);
 #define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code)
 
 #ifdef CONFIG_MODULE_UNLOAD
@@ -630,9 +619,6 @@ const char *module_address_lookup(unsigned long addr,
 int lookup_module_symbol_name(unsigned long addr, char *symname);
 int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
 
-/* For extable.c to search modules' exception tables. */
-const struct exception_table_entry *search_module_extables(unsigned long addr);
-
 int register_module_notifier(struct notifier_block *nb);
 int unregister_module_notifier(struct notifier_block *nb);
 
@@ -657,13 +643,6 @@ static inline bool is_livepatch_module(struct module *mod)
 
 #else /* !CONFIG_MODULES... */
 
-/* Given an address, look for it in the exception tables. */
-static inline const struct exception_table_entry *
-search_module_extables(unsigned long addr)
-{
-	return NULL;
-}
-
 static inline struct module *__module_address(unsigned long addr)
 {
 	return NULL;
@@ -788,12 +767,12 @@ extern int module_sysfs_initialized;
 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
 extern void set_all_modules_text_rw(void);
 extern void set_all_modules_text_ro(void);
-extern void module_enable_ro(const struct module *mod);
+extern void module_enable_ro(const struct module *mod, bool after_init);
 extern void module_disable_ro(const struct module *mod);
 #else
 static inline void set_all_modules_text_rw(void) { }
 static inline void set_all_modules_text_ro(void) { }
-static inline void module_enable_ro(const struct module *mod) { }
+static inline void module_enable_ro(const struct module *mod, bool after_init) { }
 static inline void module_disable_ro(const struct module *mod) { }
 #endif
 
diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
index cb4a72f..70b172ba 100644
--- a/include/uapi/linux/elf.h
+++ b/include/uapi/linux/elf.h
@@ -286,6 +286,7 @@ typedef struct elf64_phdr {
 #define SHF_ALLOC		0x2
 #define SHF_EXECINSTR		0x4
 #define SHF_RELA_LIVEPATCH	0x00100000
+#define SHF_RO_AFTER_INIT	0x00200000
 #define SHF_MASKPROC		0xf0000000
 
 /* special section indexes */
diff --git a/kernel/jump_label.c b/kernel/jump_label.c
index f19aa02..2040005 100644
--- a/kernel/jump_label.c
+++ b/kernel/jump_label.c
@@ -337,11 +337,14 @@ static int __jump_label_mod_text_reserved(void *start, void *end)
 {
 	struct module *mod;
 
+	preempt_disable();
 	mod = __module_text_address((unsigned long)start);
+	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
+	preempt_enable();
+
 	if (!mod)
 		return 0;
 
-	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
 
 	return __jump_label_text_reserved(mod->jump_entries,
 				mod->jump_entries + mod->num_jump_entries,
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 5c2bc10..8bbe507 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -309,7 +309,7 @@ static int klp_write_object_relocations(struct module *pmod,
 			break;
 	}
 
-	module_enable_ro(pmod);
+	module_enable_ro(pmod, true);
 	return ret;
 }
 
diff --git a/kernel/module.c b/kernel/module.c
index a0f48b8..529efae 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -265,7 +265,7 @@ static void module_assert_mutex_or_preempt(void)
 	if (unlikely(!debug_locks))
 		return;
 
-	WARN_ON(!rcu_read_lock_sched_held() &&
+	WARN_ON_ONCE(!rcu_read_lock_sched_held() &&
 		!lockdep_is_held(&module_mutex));
 #endif
 }
@@ -337,7 +337,7 @@ static inline void add_taint_module(struct module *mod, unsigned flag,
  * A thread that wants to hold a reference to a module only while it
  * is running can call this to safely exit.  nfsd and lockd use this.
  */
-void __module_put_and_exit(struct module *mod, long code)
+void __noreturn __module_put_and_exit(struct module *mod, long code)
 {
 	module_put(mod);
 	do_exit(code);
@@ -1694,8 +1694,7 @@ static int module_add_modinfo_attrs(struct module *mod)
 
 	temp_attr = mod->modinfo_attrs;
 	for (i = 0; (attr = modinfo_attrs[i]) && !error; i++) {
-		if (!attr->test ||
-		    (attr->test && attr->test(mod))) {
+		if (!attr->test || attr->test(mod)) {
 			memcpy(temp_attr, attr, sizeof(*temp_attr));
 			sysfs_attr_init(&temp_attr->attr);
 			error = sysfs_create_file(&mod->mkobj.kobj,
@@ -1859,10 +1858,11 @@ static void mod_sysfs_teardown(struct module *mod)
  * from modification and any data from execution.
  *
  * General layout of module is:
- *          [text] [read-only-data] [writable data]
- * text_size -----^                ^               ^
- * ro_size ------------------------|               |
- * size -------------------------------------------|
+ *          [text] [read-only-data] [ro-after-init] [writable data]
+ * text_size -----^                ^               ^               ^
+ * ro_size ------------------------|               |               |
+ * ro_after_init_size -----------------------------|               |
+ * size -----------------------------------------------------------|
  *
  * These values are always page-aligned (as is base)
  */
@@ -1885,14 +1885,24 @@ static void frob_rodata(const struct module_layout *layout,
 		   (layout->ro_size - layout->text_size) >> PAGE_SHIFT);
 }
 
+static void frob_ro_after_init(const struct module_layout *layout,
+				int (*set_memory)(unsigned long start, int num_pages))
+{
+	BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
+	BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
+	BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
+	set_memory((unsigned long)layout->base + layout->ro_size,
+		   (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT);
+}
+
 static void frob_writable_data(const struct module_layout *layout,
 			       int (*set_memory)(unsigned long start, int num_pages))
 {
 	BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
-	BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
+	BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
 	BUG_ON((unsigned long)layout->size & (PAGE_SIZE-1));
-	set_memory((unsigned long)layout->base + layout->ro_size,
-		   (layout->size - layout->ro_size) >> PAGE_SHIFT);
+	set_memory((unsigned long)layout->base + layout->ro_after_init_size,
+		   (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT);
 }
 
 /* livepatching wants to disable read-only so it can frob module. */
@@ -1900,21 +1910,26 @@ void module_disable_ro(const struct module *mod)
 {
 	frob_text(&mod->core_layout, set_memory_rw);
 	frob_rodata(&mod->core_layout, set_memory_rw);
+	frob_ro_after_init(&mod->core_layout, set_memory_rw);
 	frob_text(&mod->init_layout, set_memory_rw);
 	frob_rodata(&mod->init_layout, set_memory_rw);
 }
 
-void module_enable_ro(const struct module *mod)
+void module_enable_ro(const struct module *mod, bool after_init)
 {
 	frob_text(&mod->core_layout, set_memory_ro);
 	frob_rodata(&mod->core_layout, set_memory_ro);
 	frob_text(&mod->init_layout, set_memory_ro);
 	frob_rodata(&mod->init_layout, set_memory_ro);
+
+	if (after_init)
+		frob_ro_after_init(&mod->core_layout, set_memory_ro);
 }
 
 static void module_enable_nx(const struct module *mod)
 {
 	frob_rodata(&mod->core_layout, set_memory_nx);
+	frob_ro_after_init(&mod->core_layout, set_memory_nx);
 	frob_writable_data(&mod->core_layout, set_memory_nx);
 	frob_rodata(&mod->init_layout, set_memory_nx);
 	frob_writable_data(&mod->init_layout, set_memory_nx);
@@ -1923,6 +1938,7 @@ static void module_enable_nx(const struct module *mod)
 static void module_disable_nx(const struct module *mod)
 {
 	frob_rodata(&mod->core_layout, set_memory_x);
+	frob_ro_after_init(&mod->core_layout, set_memory_x);
 	frob_writable_data(&mod->core_layout, set_memory_x);
 	frob_rodata(&mod->init_layout, set_memory_x);
 	frob_writable_data(&mod->init_layout, set_memory_x);
@@ -1965,6 +1981,8 @@ static void disable_ro_nx(const struct module_layout *layout)
 	frob_text(layout, set_memory_rw);
 	frob_rodata(layout, set_memory_rw);
 	frob_rodata(layout, set_memory_x);
+	frob_ro_after_init(layout, set_memory_rw);
+	frob_ro_after_init(layout, set_memory_x);
 	frob_writable_data(layout, set_memory_x);
 }
 
@@ -2307,6 +2325,7 @@ static void layout_sections(struct module *mod, struct load_info *info)
 		 * 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 }
 	};
@@ -2338,7 +2357,11 @@ static void layout_sections(struct module *mod, struct load_info *info)
 			mod->core_layout.size = debug_align(mod->core_layout.size);
 			mod->core_layout.ro_size = mod->core_layout.size;
 			break;
-		case 3: /* whole core */
+		case 2: /* RO after init */
+			mod->core_layout.size = debug_align(mod->core_layout.size);
+			mod->core_layout.ro_after_init_size = mod->core_layout.size;
+			break;
+		case 4: /* whole core */
 			mod->core_layout.size = debug_align(mod->core_layout.size);
 			break;
 		}
@@ -2368,7 +2391,14 @@ static void layout_sections(struct module *mod, struct load_info *info)
 			mod->init_layout.size = debug_align(mod->init_layout.size);
 			mod->init_layout.ro_size = mod->init_layout.size;
 			break;
-		case 3: /* whole init */
+		case 2:
+			/*
+			 * RO after init doesn't apply to init_layout (only
+			 * core_layout), so it just takes the value of ro_size.
+			 */
+			mod->init_layout.ro_after_init_size = mod->init_layout.ro_size;
+			break;
+		case 4: /* whole init */
 			mod->init_layout.size = debug_align(mod->init_layout.size);
 			break;
 		}
@@ -2688,13 +2718,18 @@ static inline void kmemleak_load_module(const struct module *mod,
 #endif
 
 #ifdef CONFIG_MODULE_SIG
-static int module_sig_check(struct load_info *info)
+static int module_sig_check(struct load_info *info, int flags)
 {
 	int err = -ENOKEY;
 	const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
 	const void *mod = info->hdr;
 
-	if (info->len > markerlen &&
+	/*
+	 * Require flags == 0, as a module with version information
+	 * removed is no longer the module that was signed
+	 */
+	if (flags == 0 &&
+	    info->len > markerlen &&
 	    memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
 		/* We truncate the module to discard the signature */
 		info->len -= markerlen;
@@ -2713,7 +2748,7 @@ static int module_sig_check(struct load_info *info)
 	return err;
 }
 #else /* !CONFIG_MODULE_SIG */
-static int module_sig_check(struct load_info *info)
+static int module_sig_check(struct load_info *info, int flags)
 {
 	return 0;
 }
@@ -2921,8 +2956,12 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
 		return -ENOEXEC;
 	}
 
-	if (!get_modinfo(info, "intree"))
+	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);
+	}
 
 	if (get_modinfo(info, "staging")) {
 		add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
@@ -3091,6 +3130,8 @@ static int move_module(struct module *mod, struct load_info *info)
 
 static int check_module_license_and_versions(struct module *mod)
 {
+	int prev_taint = test_taint(TAINT_PROPRIETARY_MODULE);
+
 	/*
 	 * ndiswrapper is under GPL by itself, but loads proprietary modules.
 	 * Don't use add_taint_module(), as it would prevent ndiswrapper from
@@ -3109,6 +3150,9 @@ static int check_module_license_and_versions(struct module *mod)
 		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);
+
 #ifdef CONFIG_MODVERSIONS
 	if ((mod->num_syms && !mod->crcs)
 	    || (mod->num_gpl_syms && !mod->gpl_crcs)
@@ -3156,16 +3200,41 @@ int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
 	return 0;
 }
 
+/* module_blacklist is a comma-separated list of module names */
+static char *module_blacklist;
+static bool blacklisted(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)
 {
 	/* 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(mod->name))
+		return ERR_PTR(-EPERM);
+
 	err = check_modinfo(mod, info, flags);
 	if (err)
 		return ERR_PTR(err);
@@ -3179,6 +3248,15 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
 	/* 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;
+
 	/* 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. */
@@ -3345,12 +3423,14 @@ 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);
 	mod_tree_remove_init(mod);
 	disable_ro_nx(&mod->init_layout);
 	module_arch_freeing_init(mod);
 	mod->init_layout.base = NULL;
 	mod->init_layout.size = 0;
 	mod->init_layout.ro_size = 0;
+	mod->init_layout.ro_after_init_size = 0;
 	mod->init_layout.text_size = 0;
 	/*
 	 * We want to free module_init, but be aware that kallsyms may be
@@ -3442,8 +3522,7 @@ static int complete_formation(struct module *mod, struct load_info *info)
 	/* This relies on module_mutex for list integrity. */
 	module_bug_finalize(info->hdr, info->sechdrs, mod);
 
-	/* Set RO and NX regions */
-	module_enable_ro(mod);
+	module_enable_ro(mod, false);
 	module_enable_nx(mod);
 
 	/* Mark state as coming so strong_try_module_get() ignores us,
@@ -3499,7 +3578,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	long err;
 	char *after_dashes;
 
-	err = module_sig_check(info);
+	err = module_sig_check(info, flags);
 	if (err)
 		goto free_copy;