Merge tag 'pull-filename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs 'struct filename' updates from Al Viro:
 "[Mostly] sanitize struct filename handling"

* tag 'pull-filename' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (68 commits)
  sysfs(2): fs_index() argument is _not_ a pathname
  alpha: switch osf_mount() to strndup_user()
  ksmbd: use CLASS(filename_kernel)
  mqueue: switch to CLASS(filename)
  user_statfs(): switch to CLASS(filename)
  statx: switch to CLASS(filename_maybe_null)
  quotactl_block(): switch to CLASS(filename)
  chroot(2): switch to CLASS(filename)
  move_mount(2): switch to CLASS(filename_maybe_null)
  namei.c: switch user pathname imports to CLASS(filename{,_flags})
  namei.c: convert getname_kernel() callers to CLASS(filename_kernel)
  do_f{chmod,chown,access}at(): use CLASS(filename_uflags)
  do_readlinkat(): switch to CLASS(filename_flags)
  do_sys_truncate(): switch to CLASS(filename)
  do_utimes_path(): switch to CLASS(filename_uflags)
  chdir(2): unspaghettify a bit...
  do_fchownat(): unspaghettify a bit...
  fspick(2): use CLASS(filename_flags)
  name_to_handle_at(): use CLASS(filename_uflags)
  vfs_open_tree(): use CLASS(filename_uflags)
  ...

3 files changed, 30 insertions, 25 deletions

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 8ca130af301f..eeb070f330bd 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -972,7 +972,8 @@
 #define RUNTIME_CONST_VARIABLES						\
 		RUNTIME_CONST(shift, d_hash_shift)			\
 		RUNTIME_CONST(ptr, dentry_hashtable)			\
-		RUNTIME_CONST(ptr, __dentry_cache)
+		RUNTIME_CONST(ptr, __dentry_cache)			\
+		RUNTIME_CONST(ptr, __names_cache)
 
 /* Alignment must be consistent with (kunit_suite *) in include/kunit/test.h */
 #define KUNIT_TABLE()							\
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 04d16895c56a..a5be09c8497a 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -318,7 +318,6 @@ extern void __audit_uring_exit(int success, long code);
 extern void __audit_syscall_entry(int major, unsigned long a0, unsigned long a1,
 				  unsigned long a2, unsigned long a3);
 extern void __audit_syscall_exit(int ret_success, long ret_value);
-extern struct filename *__audit_reusename(const __user char *uptr);
 extern void __audit_getname(struct filename *name);
 extern void __audit_inode(struct filename *name, const struct dentry *dentry,
 				unsigned int flags);
@@ -382,12 +381,6 @@ static inline void audit_syscall_exit(void *pt_regs)
 		__audit_syscall_exit(success, return_code);
 	}
 }
-static inline struct filename *audit_reusename(const __user char *name)
-{
-	if (unlikely(!audit_dummy_context()))
-		return __audit_reusename(name);
-	return NULL;
-}
 static inline void audit_getname(struct filename *name)
 {
 	if (unlikely(!audit_dummy_context()))
@@ -626,10 +619,6 @@ static inline struct audit_context *audit_context(void)
 {
 	return NULL;
 }
-static inline struct filename *audit_reusename(const __user char *name)
-{
-	return NULL;
-}
 static inline void audit_getname(struct filename *name)
 { }
 static inline void audit_inode(struct filename *name,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 73911f961c7e..2e4d1e8b0e71 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2418,14 +2418,19 @@ extern struct kobject *fs_kobj;
 
 /* fs/open.c */
 struct audit_names;
-struct filename {
+
+struct __filename_head {
 	const char		*name;	/* pointer to actual string */
-	const __user char	*uptr;	/* original userland pointer */
-	atomic_t		refcnt;
+	int			refcnt;
 	struct audit_names	*aname;
-	const char		iname[];
+};
+#define EMBEDDED_NAME_MAX	(192 - sizeof(struct __filename_head))
+struct filename {
+	struct __filename_head;
+	const char		iname[EMBEDDED_NAME_MAX];
 };
 static_assert(offsetof(struct filename, iname) % sizeof(long) == 0);
+static_assert(sizeof(struct filename) % 64 == 0);
 
 static inline struct mnt_idmap *file_mnt_idmap(const struct file *file)
 {
@@ -2520,11 +2525,23 @@ static inline struct filename *getname_maybe_null(const char __user *name, int f
 extern void putname(struct filename *name);
 DEFINE_FREE(putname, struct filename *, if (!IS_ERR_OR_NULL(_T)) putname(_T))
 
-static inline struct filename *refname(struct filename *name)
-{
-	atomic_inc(&name->refcnt);
-	return name;
-}
+struct delayed_filename {
+	struct filename *__incomplete_filename;	// don't touch
+};
+#define INIT_DELAYED_FILENAME(ptr) \
+	((void)(*(ptr) = (struct delayed_filename){}))
+int delayed_getname(struct delayed_filename *, const char __user *);
+int delayed_getname_uflags(struct delayed_filename *v, const char __user *, int);
+void dismiss_delayed_filename(struct delayed_filename *);
+int putname_to_delayed(struct delayed_filename *, struct filename *);
+struct filename *complete_getname(struct delayed_filename *);
+
+DEFINE_CLASS(filename, struct filename *, putname(_T), getname(p), const char __user *p)
+EXTEND_CLASS(filename, _kernel, getname_kernel(p), const char *p)
+EXTEND_CLASS(filename, _flags, getname_flags(p, f), const char __user *p, unsigned int f)
+EXTEND_CLASS(filename, _uflags, getname_uflags(p, f), const char __user *p, unsigned int f)
+EXTEND_CLASS(filename, _maybe_null, getname_maybe_null(p, f), const char __user *p, unsigned int f)
+EXTEND_CLASS(filename, _complete_delayed, complete_getname(p), struct delayed_filename *p)
 
 extern int finish_open(struct file *file, struct dentry *dentry,
 			int (*open)(struct inode *, struct file *));
@@ -2543,10 +2560,8 @@ static inline int finish_open_simple(struct file *file, int error)
 extern void __init vfs_caches_init_early(void);
 extern void __init vfs_caches_init(void);
 
-extern struct kmem_cache *names_cachep;
-
-#define __getname()		kmem_cache_alloc(names_cachep, GFP_KERNEL)
-#define __putname(name)		kmem_cache_free(names_cachep, (void *)(name))
+#define __getname()		kmalloc(PATH_MAX, GFP_KERNEL)
+#define __putname(name)		kfree(name)
 
 void emergency_thaw_all(void);
 extern int sync_filesystem(struct super_block *);