1 files changed, 143 insertions, 73 deletions

diff --git a/fs/namei.c b/fs/namei.c
index aa30d19e9edd..d1895f308156 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -117,18 +117,70 @@
  * POSIX.1 2.4: an empty pathname is invalid (ENOENT).
  * PATH_MAX includes the nul terminator --RR.
  */
-static char *getname_flags(const char __user *filename, int flags, int *empty)
+void final_putname(struct filename *name)
 {
-	char *result = __getname(), *err;
+	if (name->separate) {
+		__putname(name->name);
+		kfree(name);
+	} else {
+		__putname(name);
+	}
+}
+
+#define EMBEDDED_NAME_MAX	(PATH_MAX - sizeof(struct filename))
+
+static struct filename *
+getname_flags(const char __user *filename, int flags, int *empty)
+{
+	struct filename *result, *err;
 	int len;
+	long max;
+	char *kname;
 
+	result = audit_reusename(filename);
+	if (result)
+		return result;
+
+	result = __getname();
 	if (unlikely(!result))
 		return ERR_PTR(-ENOMEM);
 
-	len = strncpy_from_user(result, filename, PATH_MAX);
-	err = ERR_PTR(len);
-	if (unlikely(len < 0))
+	/*
+	 * First, try to embed the struct filename inside the names_cache
+	 * allocation
+	 */
+	kname = (char *)result + sizeof(*result);
+	result->name = kname;
+	result->separate = false;
+	max = EMBEDDED_NAME_MAX;
+
+recopy:
+	len = strncpy_from_user(kname, filename, max);
+	if (unlikely(len < 0)) {
+		err = ERR_PTR(len);
 		goto error;
+	}
+
+	/*
+	 * Uh-oh. We have a name that's approaching PATH_MAX. Allocate a
+	 * separate struct filename so we can dedicate the entire
+	 * names_cache allocation for the pathname, and re-do the copy from
+	 * userland.
+	 */
+	if (len == EMBEDDED_NAME_MAX && max == EMBEDDED_NAME_MAX) {
+		kname = (char *)result;
+
+		result = kzalloc(sizeof(*result), GFP_KERNEL);
+		if (!result) {
+			err = ERR_PTR(-ENOMEM);
+			result = (struct filename *)kname;
+			goto error;
+		}
+		result->name = kname;
+		result->separate = true;
+		max = PATH_MAX;
+		goto recopy;
+	}
 
 	/* The empty path is special. */
 	if (unlikely(!len)) {
@@ -140,30 +192,32 @@ static char *getname_flags(const char __user *filename, int flags, int *empty)
 	}
 
 	err = ERR_PTR(-ENAMETOOLONG);
-	if (likely(len < PATH_MAX)) {
-		audit_getname(result);
-		return result;
-	}
+	if (unlikely(len >= PATH_MAX))
+		goto error;
+
+	result->uptr = filename;
+	audit_getname(result);
+	return result;
 
 error:
-	__putname(result);
+	final_putname(result);
 	return err;
 }
 
-char *getname(const char __user * filename)
+struct filename *
+getname(const char __user * filename)
 {
 	return getname_flags(filename, 0, NULL);
 }
+EXPORT_SYMBOL(getname);
 
 #ifdef CONFIG_AUDITSYSCALL
-void putname(const char *name)
+void putname(struct filename *name)
 {
 	if (unlikely(!audit_dummy_context()))
-		audit_putname(name);
-	else
-		__putname(name);
+		return audit_putname(name);
+	final_putname(name);
 }
-EXPORT_SYMBOL(putname);
 #endif
 
 static int check_acl(struct inode *inode, int mask)
@@ -692,9 +746,9 @@ static inline int may_follow_link(struct path *link, struct nameidata *nd)
 	if (uid_eq(parent->i_uid, inode->i_uid))
 		return 0;
 
+	audit_log_link_denied("follow_link", link);
 	path_put_conditional(link, nd);
 	path_put(&nd->path);
-	audit_log_link_denied("follow_link", link);
 	return -EACCES;
 }
 
@@ -810,6 +864,7 @@ follow_link(struct path *link, struct nameidata *nd, void **p)
 	return error;
 
 out_put_nd_path:
+	*p = NULL;
 	path_put(&nd->path);
 	path_put(link);
 	return error;
@@ -1962,24 +2017,29 @@ static int path_lookupat(int dfd, const char *name,
 	return err;
 }
 
-static int do_path_lookup(int dfd, const char *name,
+static int filename_lookup(int dfd, struct filename *name,
 				unsigned int flags, struct nameidata *nd)
 {
-	int retval = path_lookupat(dfd, name, flags | LOOKUP_RCU, nd);
+	int retval = path_lookupat(dfd, name->name, flags | LOOKUP_RCU, nd);
 	if (unlikely(retval == -ECHILD))
-		retval = path_lookupat(dfd, name, flags, nd);
+		retval = path_lookupat(dfd, name->name, flags, nd);
 	if (unlikely(retval == -ESTALE))
-		retval = path_lookupat(dfd, name, flags | LOOKUP_REVAL, nd);
+		retval = path_lookupat(dfd, name->name,
+						flags | LOOKUP_REVAL, nd);
 
-	if (likely(!retval)) {
-		if (unlikely(!audit_dummy_context())) {
-			if (nd->path.dentry && nd->inode)
-				audit_inode(name, nd->path.dentry);
-		}
-	}
+	if (likely(!retval))
+		audit_inode(name, nd->path.dentry, flags & LOOKUP_PARENT);
 	return retval;
 }
 
+static int do_path_lookup(int dfd, const char *name,
+				unsigned int flags, struct nameidata *nd)
+{
+	struct filename filename = { .name = name };
+
+	return filename_lookup(dfd, &filename, flags, nd);
+}
+
 /* does lookup, returns the object with parent locked */
 struct dentry *kern_path_locked(const char *name, struct path *path)
 {
@@ -2097,13 +2157,13 @@ int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
 		 struct path *path, int *empty)
 {
 	struct nameidata nd;
-	char *tmp = getname_flags(name, flags, empty);
+	struct filename *tmp = getname_flags(name, flags, empty);
 	int err = PTR_ERR(tmp);
 	if (!IS_ERR(tmp)) {
 
 		BUG_ON(flags & LOOKUP_PARENT);
 
-		err = do_path_lookup(dfd, tmp, flags, &nd);
+		err = filename_lookup(dfd, tmp, flags, &nd);
 		putname(tmp);
 		if (!err)
 			*path = nd.path;
@@ -2117,22 +2177,28 @@ int user_path_at(int dfd, const char __user *name, unsigned flags,
 	return user_path_at_empty(dfd, name, flags, path, NULL);
 }
 
-static int user_path_parent(int dfd, const char __user *path,
-			struct nameidata *nd, char **name)
+/*
+ * NB: most callers don't do anything directly with the reference to the
+ *     to struct filename, but the nd->last pointer points into the name string
+ *     allocated by getname. So we must hold the reference to it until all
+ *     path-walking is complete.
+ */
+static struct filename *
+user_path_parent(int dfd, const char __user *path, struct nameidata *nd)
 {
-	char *s = getname(path);
+	struct filename *s = getname(path);
 	int error;
 
 	if (IS_ERR(s))
-		return PTR_ERR(s);
+		return s;
 
-	error = do_path_lookup(dfd, s, LOOKUP_PARENT, nd);
-	if (error)
+	error = filename_lookup(dfd, s, LOOKUP_PARENT, nd);
+	if (error) {
 		putname(s);
-	else
-		*name = s;
+		return ERR_PTR(error);
+	}
 
-	return error;
+	return s;
 }
 
 /*
@@ -2179,7 +2245,7 @@ static int may_delete(struct inode *dir,struct dentry *victim,int isdir)
 		return -ENOENT;
 
 	BUG_ON(victim->d_parent->d_inode != dir);
-	audit_inode_child(victim, dir);
+	audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE);
 
 	error = inode_permission(dir, MAY_WRITE | MAY_EXEC);
 	if (error)
@@ -2624,7 +2690,7 @@ out_dput:
  */
 static int do_last(struct nameidata *nd, struct path *path,
 		   struct file *file, const struct open_flags *op,
-		   int *opened, const char *pathname)
+		   int *opened, struct filename *name)
 {
 	struct dentry *dir = nd->path.dentry;
 	int open_flag = op->open_flag;
@@ -2651,7 +2717,7 @@ static int do_last(struct nameidata *nd, struct path *path,
 		error = complete_walk(nd);
 		if (error)
 			return error;
-		audit_inode(pathname, nd->path.dentry);
+		audit_inode(name, nd->path.dentry, 0);
 		if (open_flag & O_CREAT) {
 			error = -EISDIR;
 			goto out;
@@ -2661,7 +2727,7 @@ static int do_last(struct nameidata *nd, struct path *path,
 		error = complete_walk(nd);
 		if (error)
 			return error;
-		audit_inode(pathname, dir);
+		audit_inode(name, dir, 0);
 		goto finish_open;
 	}
 
@@ -2690,7 +2756,7 @@ static int do_last(struct nameidata *nd, struct path *path,
 		if (error)
 			return error;
 
-		audit_inode(pathname, dir);
+		audit_inode(name, dir, 0);
 		error = -EISDIR;
 		/* trailing slashes? */
 		if (nd->last.name[nd->last.len])
@@ -2720,7 +2786,7 @@ retry_lookup:
 		    !S_ISREG(file->f_path.dentry->d_inode->i_mode))
 			will_truncate = false;
 
-		audit_inode(pathname, file->f_path.dentry);
+		audit_inode(name, file->f_path.dentry, 0);
 		goto opened;
 	}
 
@@ -2737,7 +2803,7 @@ retry_lookup:
 	 * create/update audit record if it already exists.
 	 */
 	if (path->dentry->d_inode)
-		audit_inode(pathname, path->dentry);
+		audit_inode(name, path->dentry, 0);
 
 	/*
 	 * If atomic_open() acquired write access it is dropped now due to
@@ -2802,7 +2868,7 @@ finish_lookup:
 	error = -ENOTDIR;
 	if ((nd->flags & LOOKUP_DIRECTORY) && !nd->inode->i_op->lookup)
 		goto out;
-	audit_inode(pathname, nd->path.dentry);
+	audit_inode(name, nd->path.dentry, 0);
 finish_open:
 	if (!S_ISREG(nd->inode->i_mode))
 		will_truncate = false;
@@ -2870,7 +2936,7 @@ stale_open:
 	goto retry_lookup;
 }
 
-static struct file *path_openat(int dfd, const char *pathname,
+static struct file *path_openat(int dfd, struct filename *pathname,
 		struct nameidata *nd, const struct open_flags *op, int flags)
 {
 	struct file *base = NULL;
@@ -2885,12 +2951,12 @@ static struct file *path_openat(int dfd, const char *pathname,
 
 	file->f_flags = op->open_flag;
 
-	error = path_init(dfd, pathname, flags | LOOKUP_PARENT, nd, &base);
+	error = path_init(dfd, pathname->name, flags | LOOKUP_PARENT, nd, &base);
 	if (unlikely(error))
 		goto out;
 
 	current->total_link_count = 0;
-	error = link_path_walk(pathname, nd);
+	error = link_path_walk(pathname->name, nd);
 	if (unlikely(error))
 		goto out;
 
@@ -2936,7 +3002,7 @@ out:
 	return file;
 }
 
-struct file *do_filp_open(int dfd, const char *pathname,
+struct file *do_filp_open(int dfd, struct filename *pathname,
 		const struct open_flags *op, int flags)
 {
 	struct nameidata nd;
@@ -2955,6 +3021,7 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
 {
 	struct nameidata nd;
 	struct file *file;
+	struct filename filename = { .name = name };
 
 	nd.root.mnt = mnt;
 	nd.root.dentry = dentry;
@@ -2964,11 +3031,11 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
 	if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN)
 		return ERR_PTR(-ELOOP);
 
-	file = path_openat(-1, name, &nd, op, flags | LOOKUP_RCU);
+	file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_RCU);
 	if (unlikely(file == ERR_PTR(-ECHILD)))
-		file = path_openat(-1, name, &nd, op, flags);
+		file = path_openat(-1, &filename, &nd, op, flags);
 	if (unlikely(file == ERR_PTR(-ESTALE)))
-		file = path_openat(-1, name, &nd, op, flags | LOOKUP_REVAL);
+		file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_REVAL);
 	return file;
 }
 
@@ -3043,11 +3110,11 @@ EXPORT_SYMBOL(done_path_create);
 
 struct dentry *user_path_create(int dfd, const char __user *pathname, struct path *path, int is_dir)
 {
-	char *tmp = getname(pathname);
+	struct filename *tmp = getname(pathname);
 	struct dentry *res;
 	if (IS_ERR(tmp))
 		return ERR_CAST(tmp);
-	res = kern_path_create(dfd, tmp, path, is_dir);
+	res = kern_path_create(dfd, tmp->name, path, is_dir);
 	putname(tmp);
 	return res;
 }
@@ -3252,13 +3319,13 @@ out:
 static long do_rmdir(int dfd, const char __user *pathname)
 {
 	int error = 0;
-	char * name;
+	struct filename *name;
 	struct dentry *dentry;
 	struct nameidata nd;
 
-	error = user_path_parent(dfd, pathname, &nd, &name);
-	if (error)
-		return error;
+	name = user_path_parent(dfd, pathname, &nd);
+	if (IS_ERR(name))
+		return PTR_ERR(name);
 
 	switch(nd.last_type) {
 	case LAST_DOTDOT:
@@ -3347,14 +3414,14 @@ int vfs_unlink(struct inode *dir, struct dentry *dentry)
 static long do_unlinkat(int dfd, const char __user *pathname)
 {
 	int error;
-	char *name;
+	struct filename *name;
 	struct dentry *dentry;
 	struct nameidata nd;
 	struct inode *inode = NULL;
 
-	error = user_path_parent(dfd, pathname, &nd, &name);
-	if (error)
-		return error;
+	name = user_path_parent(dfd, pathname, &nd);
+	if (IS_ERR(name))
+		return PTR_ERR(name);
 
 	error = -EISDIR;
 	if (nd.last_type != LAST_NORM)
@@ -3438,7 +3505,7 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
 		int, newdfd, const char __user *, newname)
 {
 	int error;
-	char *from;
+	struct filename *from;
 	struct dentry *dentry;
 	struct path path;
 
@@ -3451,9 +3518,9 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
 	if (IS_ERR(dentry))
 		goto out_putname;
 
-	error = security_path_symlink(&path, dentry, from);
+	error = security_path_symlink(&path, dentry, from->name);
 	if (!error)
-		error = vfs_symlink(path.dentry->d_inode, dentry, from);
+		error = vfs_symlink(path.dentry->d_inode, dentry, from->name);
 	done_path_create(&path, dentry);
 out_putname:
 	putname(from);
@@ -3733,17 +3800,21 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
 	struct dentry *old_dentry, *new_dentry;
 	struct dentry *trap;
 	struct nameidata oldnd, newnd;
-	char *from;
-	char *to;
+	struct filename *from;
+	struct filename *to;
 	int error;
 
-	error = user_path_parent(olddfd, oldname, &oldnd, &from);
-	if (error)
+	from = user_path_parent(olddfd, oldname, &oldnd);
+	if (IS_ERR(from)) {
+		error = PTR_ERR(from);
 		goto exit;
+	}
 
-	error = user_path_parent(newdfd, newname, &newnd, &to);
-	if (error)
+	to = user_path_parent(newdfd, newname, &newnd);
+	if (IS_ERR(to)) {
+		error = PTR_ERR(to);
 		goto exit1;
+	}
 
 	error = -EXDEV;
 	if (oldnd.path.mnt != newnd.path.mnt)
@@ -3967,7 +4038,6 @@ EXPORT_SYMBOL(follow_down_one);
 EXPORT_SYMBOL(follow_down);
 EXPORT_SYMBOL(follow_up);
 EXPORT_SYMBOL(get_write_access); /* nfsd */
-EXPORT_SYMBOL(getname);
 EXPORT_SYMBOL(lock_rename);
 EXPORT_SYMBOL(lookup_one_len);
 EXPORT_SYMBOL(page_follow_link_light);