1 files changed, 114 insertions, 112 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 8358f4697c0c..041200ca4a2d 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -53,6 +53,7 @@
 #include <asm/sections.h>
 #include <linux/tracepoint.h>
 #include <linux/ftrace.h>
+#include <linux/livepatch.h>
 #include <linux/async.h>
 #include <linux/percpu.h>
 #include <linux/kmemleak.h>
@@ -303,6 +304,9 @@ struct load_info {
 	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;
@@ -981,6 +985,9 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
 		mod->exit();
 	blocking_notifier_call_chain(&module_notify_list,
 				     MODULE_STATE_GOING, mod);
+	klp_module_going(mod);
+	ftrace_release_mod(mod);
+
 	async_synchronize_full();
 
 	/* Store the name of the last unloaded module for diagnostic purposes */
@@ -2480,10 +2487,21 @@ static void layout_symtab(struct module *mod, struct load_info *info)
 	strsect->sh_flags |= SHF_ALLOC;
 	strsect->sh_entsize = get_offset(mod, &mod->init_layout.size, strsect,
 					 info->index.str) | INIT_OFFSET_MASK;
-	mod->init_layout.size = debug_align(mod->init_layout.size);
 	pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
+
+	/* We'll tack temporary mod_kallsyms on the end. */
+	mod->init_layout.size = ALIGN(mod->init_layout.size,
+				      __alignof__(struct mod_kallsyms));
+	info->mod_kallsyms_init_off = mod->init_layout.size;
+	mod->init_layout.size += sizeof(struct mod_kallsyms);
+	mod->init_layout.size = debug_align(mod->init_layout.size);
 }
 
+/*
+ * We use the full symtab and strtab which layout_symtab arranged to
+ * be appended to the init section.  Later we switch to the cut-down
+ * core-only ones.
+ */
 static void add_kallsyms(struct module *mod, const struct load_info *info)
 {
 	unsigned int i, ndst;
@@ -2492,29 +2510,34 @@ static void add_kallsyms(struct module *mod, const struct load_info *info)
 	char *s;
 	Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
 
-	mod->symtab = (void *)symsec->sh_addr;
-	mod->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
+	/* Set up to point into init section. */
+	mod->kallsyms = mod->init_layout.base + info->mod_kallsyms_init_off;
+
+	mod->kallsyms->symtab = (void *)symsec->sh_addr;
+	mod->kallsyms->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
 	/* Make sure we get permanent strtab: don't use info->strtab. */
-	mod->strtab = (void *)info->sechdrs[info->index.str].sh_addr;
+	mod->kallsyms->strtab = (void *)info->sechdrs[info->index.str].sh_addr;
 
 	/* Set types up while we still have access to sections. */
-	for (i = 0; i < mod->num_symtab; i++)
-		mod->symtab[i].st_info = elf_type(&mod->symtab[i], info);
-
-	mod->core_symtab = dst = mod->core_layout.base + info->symoffs;
-	mod->core_strtab = s = mod->core_layout.base + info->stroffs;
-	src = mod->symtab;
-	for (ndst = i = 0; i < mod->num_symtab; i++) {
+	for (i = 0; i < mod->kallsyms->num_symtab; i++)
+		mod->kallsyms->symtab[i].st_info
+			= elf_type(&mod->kallsyms->symtab[i], info);
+
+	/* Now populate the cut down core kallsyms for after init. */
+	mod->core_kallsyms.symtab = dst = mod->core_layout.base + info->symoffs;
+	mod->core_kallsyms.strtab = s = mod->core_layout.base + info->stroffs;
+	src = mod->kallsyms->symtab;
+	for (ndst = i = 0; i < mod->kallsyms->num_symtab; i++) {
 		if (i == 0 ||
 		    is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum,
 				   info->index.pcpu)) {
 			dst[ndst] = src[i];
-			dst[ndst++].st_name = s - mod->core_strtab;
-			s += strlcpy(s, &mod->strtab[src[i].st_name],
+			dst[ndst++].st_name = s - mod->core_kallsyms.strtab;
+			s += strlcpy(s, &mod->kallsyms->strtab[src[i].st_name],
 				     KSYM_NAME_LEN) + 1;
 		}
 	}
-	mod->core_num_syms = ndst;
+	mod->core_kallsyms.num_symtab = ndst;
 }
 #else
 static inline void layout_symtab(struct module *mod, struct load_info *info)
@@ -2654,7 +2677,7 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
 	if (info->len < sizeof(*(info->hdr)))
 		return -ENOEXEC;
 
-	err = security_kernel_module_from_file(NULL);
+	err = security_kernel_read_file(NULL, READING_MODULE);
 	if (err)
 		return err;
 
@@ -2672,63 +2695,6 @@ static int copy_module_from_user(const void __user *umod, unsigned long len,
 	return 0;
 }
 
-/* Sets info->hdr and info->len. */
-static int copy_module_from_fd(int fd, struct load_info *info)
-{
-	struct fd f = fdget(fd);
-	int err;
-	struct kstat stat;
-	loff_t pos;
-	ssize_t bytes = 0;
-
-	if (!f.file)
-		return -ENOEXEC;
-
-	err = security_kernel_module_from_file(f.file);
-	if (err)
-		goto out;
-
-	err = vfs_getattr(&f.file->f_path, &stat);
-	if (err)
-		goto out;
-
-	if (stat.size > INT_MAX) {
-		err = -EFBIG;
-		goto out;
-	}
-
-	/* Don't hand 0 to vmalloc, it whines. */
-	if (stat.size == 0) {
-		err = -EINVAL;
-		goto out;
-	}
-
-	info->hdr = vmalloc(stat.size);
-	if (!info->hdr) {
-		err = -ENOMEM;
-		goto out;
-	}
-
-	pos = 0;
-	while (pos < stat.size) {
-		bytes = kernel_read(f.file, pos, (char *)(info->hdr) + pos,
-				    stat.size - pos);
-		if (bytes < 0) {
-			vfree(info->hdr);
-			err = bytes;
-			goto out;
-		}
-		if (bytes == 0)
-			break;
-		pos += bytes;
-	}
-	info->len = pos;
-
-out:
-	fdput(f);
-	return err;
-}
-
 static void free_copy(struct load_info *info)
 {
 	vfree(info->hdr);
@@ -3263,9 +3229,8 @@ static noinline int do_init_module(struct module *mod)
 	module_put(mod);
 	trim_init_extable(mod);
 #ifdef CONFIG_KALLSYMS
-	mod->num_symtab = mod->core_num_syms;
-	mod->symtab = mod->core_symtab;
-	mod->strtab = mod->core_strtab;
+	/* Switch to core kallsyms now init is done: kallsyms may be walking! */
+	rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
 #endif
 	mod_tree_remove_init(mod);
 	disable_ro_nx(&mod->init_layout);
@@ -3295,6 +3260,8 @@ fail:
 	module_put(mod);
 	blocking_notifier_call_chain(&module_notify_list,
 				     MODULE_STATE_GOING, mod);
+	klp_module_going(mod);
+	ftrace_release_mod(mod);
 	free_module(mod);
 	wake_up_all(&module_wq);
 	return ret;
@@ -3371,8 +3338,6 @@ static int complete_formation(struct module *mod, struct load_info *info)
 	mod->state = MODULE_STATE_COMING;
 	mutex_unlock(&module_mutex);
 
-	blocking_notifier_call_chain(&module_notify_list,
-				     MODULE_STATE_COMING, mod);
 	return 0;
 
 out:
@@ -3380,6 +3345,20 @@ out:
 	return err;
 }
 
+static int prepare_coming_module(struct module *mod)
+{
+	int err;
+
+	ftrace_module_enable(mod);
+	err = klp_module_coming(mod);
+	if (err)
+		return err;
+
+	blocking_notifier_call_chain(&module_notify_list,
+				     MODULE_STATE_COMING, mod);
+	return 0;
+}
+
 static int unknown_module_param_cb(char *param, char *val, const char *modname,
 				   void *arg)
 {
@@ -3494,13 +3473,17 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	if (err)
 		goto ddebug_cleanup;
 
+	err = prepare_coming_module(mod);
+	if (err)
+		goto bug_cleanup;
+
 	/* Module is ready to execute: parsing args may do that. */
 	after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
-				  -32768, 32767, NULL,
+				  -32768, 32767, mod,
 				  unknown_module_param_cb);
 	if (IS_ERR(after_dashes)) {
 		err = PTR_ERR(after_dashes);
-		goto bug_cleanup;
+		goto coming_cleanup;
 	} else if (after_dashes) {
 		pr_warn("%s: parameters '%s' after `--' ignored\n",
 		       mod->name, after_dashes);
@@ -3509,7 +3492,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	/* Link in to syfs. */
 	err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
 	if (err < 0)
-		goto bug_cleanup;
+		goto coming_cleanup;
 
 	/* Get rid of temporary copy. */
 	free_copy(info);
@@ -3519,15 +3502,17 @@ static int load_module(struct load_info *info, const char __user *uargs,
 
 	return do_init_module(mod);
 
+ coming_cleanup:
+	blocking_notifier_call_chain(&module_notify_list,
+				     MODULE_STATE_GOING, mod);
+	klp_module_going(mod);
+
  bug_cleanup:
 	/* module_bug_cleanup needs module_mutex protection */
 	mutex_lock(&module_mutex);
 	module_bug_cleanup(mod);
 	mutex_unlock(&module_mutex);
 
-	blocking_notifier_call_chain(&module_notify_list,
-				     MODULE_STATE_GOING, mod);
-
 	/* we can't deallocate the module until we clear memory protection */
 	module_disable_ro(mod);
 	module_disable_nx(mod);
@@ -3589,8 +3574,10 @@ SYSCALL_DEFINE3(init_module, void __user *, umod,
 
 SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 {
-	int err;
 	struct load_info info = { };
+	loff_t size;
+	void *hdr;
+	int err;
 
 	err = may_init_module();
 	if (err)
@@ -3602,9 +3589,12 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
 		      |MODULE_INIT_IGNORE_VERMAGIC))
 		return -EINVAL;
 
-	err = copy_module_from_fd(fd, &info);
+	err = kernel_read_file_from_fd(fd, &hdr, &size, INT_MAX,
+				       READING_MODULE);
 	if (err)
 		return err;
+	info.hdr = hdr;
+	info.len = size;
 
 	return load_module(&info, uargs, flags);
 }
@@ -3627,6 +3617,11 @@ static inline int is_arm_mapping_symbol(const char *str)
 	       && (str[2] == '\0' || str[2] == '.');
 }
 
+static const char *symname(struct mod_kallsyms *kallsyms, unsigned int symnum)
+{
+	return kallsyms->strtab + kallsyms->symtab[symnum].st_name;
+}
+
 static const char *get_ksymbol(struct module *mod,
 			       unsigned long addr,
 			       unsigned long *size,
@@ -3634,6 +3629,7 @@ static const char *get_ksymbol(struct module *mod,
 {
 	unsigned int i, best = 0;
 	unsigned long nextval;
+	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
 
 	/* At worse, next value is at end of module */
 	if (within_module_init(addr, mod))
@@ -3643,32 +3639,32 @@ static const char *get_ksymbol(struct module *mod,
 
 	/* Scan for closest preceding symbol, and next symbol. (ELF
 	   starts real symbols at 1). */
-	for (i = 1; i < mod->num_symtab; i++) {
-		if (mod->symtab[i].st_shndx == SHN_UNDEF)
+	for (i = 1; i < kallsyms->num_symtab; i++) {
+		if (kallsyms->symtab[i].st_shndx == SHN_UNDEF)
 			continue;
 
 		/* We ignore unnamed symbols: they're uninformative
 		 * and inserted at a whim. */
-		if (mod->symtab[i].st_value <= addr
-		    && mod->symtab[i].st_value > mod->symtab[best].st_value
-		    && *(mod->strtab + mod->symtab[i].st_name) != '\0'
-		    && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
+		if (*symname(kallsyms, i) == '\0'
+		    || is_arm_mapping_symbol(symname(kallsyms, i)))
+			continue;
+
+		if (kallsyms->symtab[i].st_value <= addr
+		    && kallsyms->symtab[i].st_value > kallsyms->symtab[best].st_value)
 			best = i;
-		if (mod->symtab[i].st_value > addr
-		    && mod->symtab[i].st_value < nextval
-		    && *(mod->strtab + mod->symtab[i].st_name) != '\0'
-		    && !is_arm_mapping_symbol(mod->strtab + mod->symtab[i].st_name))
-			nextval = mod->symtab[i].st_value;
+		if (kallsyms->symtab[i].st_value > addr
+		    && kallsyms->symtab[i].st_value < nextval)
+			nextval = kallsyms->symtab[i].st_value;
 	}
 
 	if (!best)
 		return NULL;
 
 	if (size)
-		*size = nextval - mod->symtab[best].st_value;
+		*size = nextval - kallsyms->symtab[best].st_value;
 	if (offset)
-		*offset = addr - mod->symtab[best].st_value;
-	return mod->strtab + mod->symtab[best].st_name;
+		*offset = addr - kallsyms->symtab[best].st_value;
+	return symname(kallsyms, best);
 }
 
 /* For kallsyms to ask for address resolution.  NULL means not found.  Careful
@@ -3758,19 +3754,21 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 
 	preempt_disable();
 	list_for_each_entry_rcu(mod, &modules, list) {
+		struct mod_kallsyms *kallsyms;
+
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
-		if (symnum < mod->num_symtab) {
-			*value = mod->symtab[symnum].st_value;
-			*type = mod->symtab[symnum].st_info;
-			strlcpy(name, mod->strtab + mod->symtab[symnum].st_name,
-				KSYM_NAME_LEN);
+		kallsyms = rcu_dereference_sched(mod->kallsyms);
+		if (symnum < kallsyms->num_symtab) {
+			*value = kallsyms->symtab[symnum].st_value;
+			*type = kallsyms->symtab[symnum].st_info;
+			strlcpy(name, symname(kallsyms, symnum), KSYM_NAME_LEN);
 			strlcpy(module_name, mod->name, MODULE_NAME_LEN);
 			*exported = is_exported(name, *value, mod);
 			preempt_enable();
 			return 0;
 		}
-		symnum -= mod->num_symtab;
+		symnum -= kallsyms->num_symtab;
 	}
 	preempt_enable();
 	return -ERANGE;
@@ -3779,11 +3777,12 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 static unsigned long mod_find_symname(struct module *mod, const char *name)
 {
 	unsigned int i;
+	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
 
-	for (i = 0; i < mod->num_symtab; i++)
-		if (strcmp(name, mod->strtab+mod->symtab[i].st_name) == 0 &&
-		    mod->symtab[i].st_info != 'U')
-			return mod->symtab[i].st_value;
+	for (i = 0; i < kallsyms->num_symtab; i++)
+		if (strcmp(name, symname(kallsyms, i)) == 0 &&
+		    kallsyms->symtab[i].st_info != 'U')
+			return kallsyms->symtab[i].st_value;
 	return 0;
 }
 
@@ -3822,11 +3821,14 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 	module_assert_mutex();
 
 	list_for_each_entry(mod, &modules, list) {
+		/* We hold module_mutex: no need for rcu_dereference_sched */
+		struct mod_kallsyms *kallsyms = mod->kallsyms;
+
 		if (mod->state == MODULE_STATE_UNFORMED)
 			continue;
-		for (i = 0; i < mod->num_symtab; i++) {
-			ret = fn(data, mod->strtab + mod->symtab[i].st_name,
-				 mod, mod->symtab[i].st_value);
+		for (i = 0; i < kallsyms->num_symtab; i++) {
+			ret = fn(data, symname(kallsyms, i),
+				 mod, kallsyms->symtab[i].st_value);
 			if (ret != 0)
 				return ret;
 		}