1 files changed, 84 insertions, 62 deletions

diff --git a/fs/namei.c b/fs/namei.c
index 43927d14db6..bc35b02883b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -130,7 +130,7 @@ void final_putname(struct filename *name)
 
 #define EMBEDDED_NAME_MAX	(PATH_MAX - sizeof(struct filename))
 
-static struct filename *
+struct filename *
 getname_flags(const char __user *filename, int flags, int *empty)
 {
 	struct filename *result, *err;
@@ -416,6 +416,7 @@ int __inode_permission(struct inode *inode, int mask)
 
 	return security_inode_permission(inode, mask);
 }
+EXPORT_SYMBOL(__inode_permission);
 
 /**
  * sb_permission - Check superblock-level permissions
@@ -486,6 +487,19 @@ void path_put(const struct path *path)
 }
 EXPORT_SYMBOL(path_put);
 
+struct nameidata {
+	struct path	path;
+	struct qstr	last;
+	struct path	root;
+	struct inode	*inode; /* path.dentry.d_inode */
+	unsigned int	flags;
+	unsigned	seq, m_seq;
+	int		last_type;
+	unsigned	depth;
+	struct file	*base;
+	char *saved_names[MAX_NESTED_LINKS + 1];
+};
+
 /*
  * Path walking has 2 modes, rcu-walk and ref-walk (see
  * Documentation/filesystems/path-lookup.txt).  In situations when we can't
@@ -694,6 +708,18 @@ void nd_jump_link(struct nameidata *nd, struct path *path)
 	nd->flags |= LOOKUP_JUMPED;
 }
 
+void nd_set_link(struct nameidata *nd, char *path)
+{
+	nd->saved_names[nd->depth] = path;
+}
+EXPORT_SYMBOL(nd_set_link);
+
+char *nd_get_link(struct nameidata *nd)
+{
+	return nd->saved_names[nd->depth];
+}
+EXPORT_SYMBOL(nd_get_link);
+
 static inline void put_link(struct nameidata *nd, struct path *link, void *cookie)
 {
 	struct inode *inode = link->dentry->d_inode;
@@ -1820,13 +1846,14 @@ static int link_path_walk(const char *name, struct nameidata *nd)
 }
 
 static int path_init(int dfd, const char *name, unsigned int flags,
-		     struct nameidata *nd, struct file **fp)
+		     struct nameidata *nd)
 {
 	int retval = 0;
 
 	nd->last_type = LAST_ROOT; /* if there are only slashes... */
-	nd->flags = flags | LOOKUP_JUMPED;
+	nd->flags = flags | LOOKUP_JUMPED | LOOKUP_PARENT;
 	nd->depth = 0;
+	nd->base = NULL;
 	if (flags & LOOKUP_ROOT) {
 		struct dentry *root = nd->root.dentry;
 		struct inode *inode = root->d_inode;
@@ -1846,7 +1873,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
 		} else {
 			path_get(&nd->path);
 		}
-		return 0;
+		goto done;
 	}
 
 	nd->root.mnt = NULL;
@@ -1896,7 +1923,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
 		nd->path = f.file->f_path;
 		if (flags & LOOKUP_RCU) {
 			if (f.flags & FDPUT_FPUT)
-				*fp = f.file;
+				nd->base = f.file;
 			nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
 			rcu_read_lock();
 		} else {
@@ -1907,13 +1934,26 @@ static int path_init(int dfd, const char *name, unsigned int flags,
 
 	nd->inode = nd->path.dentry->d_inode;
 	if (!(flags & LOOKUP_RCU))
-		return 0;
+		goto done;
 	if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq)))
-		return 0;
+		goto done;
 	if (!(nd->flags & LOOKUP_ROOT))
 		nd->root.mnt = NULL;
 	rcu_read_unlock();
 	return -ECHILD;
+done:
+	current->total_link_count = 0;
+	return link_path_walk(name, nd);
+}
+
+static void path_cleanup(struct nameidata *nd)
+{
+	if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
+		path_put(&nd->root);
+		nd->root.mnt = NULL;
+	}
+	if (unlikely(nd->base))
+		fput(nd->base);
 }
 
 static inline int lookup_last(struct nameidata *nd, struct path *path)
@@ -1929,7 +1969,6 @@ static inline int lookup_last(struct nameidata *nd, struct path *path)
 static int path_lookupat(int dfd, const char *name,
 				unsigned int flags, struct nameidata *nd)
 {
-	struct file *base = NULL;
 	struct path path;
 	int err;
 
@@ -1947,14 +1986,7 @@ static int path_lookupat(int dfd, const char *name,
 	 * be handled by restarting a traditional ref-walk (which will always
 	 * be able to complete).
 	 */
-	err = path_init(dfd, name, flags | LOOKUP_PARENT, nd, &base);
-
-	if (unlikely(err))
-		goto out;
-
-	current->total_link_count = 0;
-	err = link_path_walk(name, nd);
-
+	err = path_init(dfd, name, flags, nd);
 	if (!err && !(flags & LOOKUP_PARENT)) {
 		err = lookup_last(nd, &path);
 		while (err > 0) {
@@ -1982,14 +2014,7 @@ static int path_lookupat(int dfd, const char *name,
 		}
 	}
 
-out:
-	if (base)
-		fput(base);
-
-	if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) {
-		path_put(&nd->root);
-		nd->root.mnt = NULL;
-	}
+	path_cleanup(nd);
 	return err;
 }
 
@@ -2296,19 +2321,13 @@ out:
 static int
 path_mountpoint(int dfd, const char *name, struct path *path, unsigned int flags)
 {
-	struct file *base = NULL;
 	struct nameidata nd;
 	int err;
 
-	err = path_init(dfd, name, flags | LOOKUP_PARENT, &nd, &base);
+	err = path_init(dfd, name, flags, &nd);
 	if (unlikely(err))
 		goto out;
 
-	current->total_link_count = 0;
-	err = link_path_walk(name, &nd);
-	if (err)
-		goto out;
-
 	err = mountpoint_last(&nd, path);
 	while (err > 0) {
 		void *cookie;
@@ -2324,12 +2343,7 @@ path_mountpoint(int dfd, const char *name, struct path *path, unsigned int flags
 		put_link(&nd, &link, cookie);
 	}
 out:
-	if (base)
-		fput(base);
-
-	if (nd.root.mnt && !(nd.flags & LOOKUP_ROOT))
-		path_put(&nd.root);
-
+	path_cleanup(&nd);
 	return err;
 }
 
@@ -2383,22 +2397,17 @@ kern_path_mountpoint(int dfd, const char *name, struct path *path,
 }
 EXPORT_SYMBOL(kern_path_mountpoint);
 
-/*
- * It's inline, so penalty for filesystems that don't use sticky bit is
- * minimal.
- */
-static inline int check_sticky(struct inode *dir, struct inode *inode)
+int __check_sticky(struct inode *dir, struct inode *inode)
 {
 	kuid_t fsuid = current_fsuid();
 
-	if (!(dir->i_mode & S_ISVTX))
-		return 0;
 	if (uid_eq(inode->i_uid, fsuid))
 		return 0;
 	if (uid_eq(dir->i_uid, fsuid))
 		return 0;
 	return !capable_wrt_inode_uidgid(inode, CAP_FOWNER);
 }
+EXPORT_SYMBOL(__check_sticky);
 
 /*
  *	Check whether we can remove a link victim from directory dir, check
@@ -2501,7 +2510,7 @@ struct dentry *lock_rename(struct dentry *p1, struct dentry *p2)
 	}
 
 	mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT);
-	mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD);
+	mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT2);
 	return NULL;
 }
 EXPORT_SYMBOL(lock_rename);
@@ -3064,9 +3073,12 @@ finish_open_created:
 	error = may_open(&nd->path, acc_mode, open_flag);
 	if (error)
 		goto out;
-	file->f_path.mnt = nd->path.mnt;
-	error = finish_open(file, nd->path.dentry, NULL, opened);
-	if (error) {
+
+	BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
+	error = vfs_open(&nd->path, file, current_cred());
+	if (!error) {
+		*opened |= FILE_OPENED;
+	} else {
 		if (error == -EOPENSTALE)
 			goto stale_open;
 		goto out;
@@ -3155,7 +3167,8 @@ static int do_tmpfile(int dfd, struct filename *pathname,
 	if (error)
 		goto out2;
 	audit_inode(pathname, nd->path.dentry, 0);
-	error = may_open(&nd->path, op->acc_mode, op->open_flag);
+	/* Don't check for other permissions, the inode was just created */
+	error = may_open(&nd->path, MAY_OPEN, op->open_flag);
 	if (error)
 		goto out2;
 	file->f_path.mnt = nd->path.mnt;
@@ -3181,7 +3194,6 @@ out:
 static struct file *path_openat(int dfd, struct filename *pathname,
 		struct nameidata *nd, const struct open_flags *op, int flags)
 {
-	struct file *base = NULL;
 	struct file *file;
 	struct path path;
 	int opened = 0;
@@ -3198,12 +3210,7 @@ static struct file *path_openat(int dfd, struct filename *pathname,
 		goto out;
 	}
 
-	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->name, nd);
+	error = path_init(dfd, pathname->name, flags, nd);
 	if (unlikely(error))
 		goto out;
 
@@ -3229,10 +3236,7 @@ static struct file *path_openat(int dfd, struct filename *pathname,
 		put_link(nd, &link, cookie);
 	}
 out:
-	if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT))
-		path_put(&nd->root);
-	if (base)
-		fput(base);
+	path_cleanup(nd);
 	if (!(opened & FILE_OPENED)) {
 		BUG_ON(!error);
 		put_filp(file);
@@ -4210,12 +4214,16 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
 	bool should_retry = false;
 	int error;
 
-	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
+	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
 		return -EINVAL;
 
-	if ((flags & RENAME_NOREPLACE) && (flags & RENAME_EXCHANGE))
+	if ((flags & (RENAME_NOREPLACE | RENAME_WHITEOUT)) &&
+	    (flags & RENAME_EXCHANGE))
 		return -EINVAL;
 
+	if ((flags & RENAME_WHITEOUT) && !capable(CAP_MKNOD))
+		return -EPERM;
+
 retry:
 	from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);
 	if (IS_ERR(from)) {
@@ -4347,6 +4355,20 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna
 	return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
+int vfs_whiteout(struct inode *dir, struct dentry *dentry)
+{
+	int error = may_create(dir, dentry);
+	if (error)
+		return error;
+
+	if (!dir->i_op->mknod)
+		return -EPERM;
+
+	return dir->i_op->mknod(dir, dentry,
+				S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV);
+}
+EXPORT_SYMBOL(vfs_whiteout);
+
 int readlink_copy(char __user *buffer, int buflen, const char *link)
 {
 	int len = PTR_ERR(link);