[PATCH v28 01/21] vfs: Add IS_ACL() and IS_RICHACL() tests

[Andreas Gruenbacher]

The vfs does not apply the umask for file systems that support acls.
The test used for this used to be called IS_POSIXACL().  Switch to a new
IS_ACL() test to check for either posix acls or richacls instead.  Add a
new MS_RICHACL flag and IS_RICHACL() test for richacls alone.  The
IS_POSIXACL() test is still needed in some places like nfsd.

Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Reviewed-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
Reviewed-by: Steve French <steve.french@xxxxxxxxxxxxxxx>
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
 fs/Kconfig              |  3 +++
 fs/namei.c              |  6 +++---
 include/linux/fs.h      | 12 ++++++++++++
 include/uapi/linux/fs.h |  3 ++-
 4 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/fs/Kconfig b/fs/Kconfig
index 83eab52..6e1d1f6 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -67,6 +67,9 @@ endif # BLOCK
 config FS_POSIX_ACL
 	def_bool n
 
+config FS_RICHACL
+	def_bool n
+
 config EXPORTFS
 	tristate
 
diff --git a/fs/namei.c b/fs/namei.c
index ad74877..81ae757 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3096,7 +3096,7 @@ static int lookup_open(struct nameidata *nd, struct path *path,
 	 * O_EXCL open we want to return EEXIST not EROFS).
 	 */
 	if (open_flag & O_CREAT) {
-		if (!IS_POSIXACL(dir->d_inode))
+		if (!IS_ACL(dir->d_inode))
 			mode &= ~current_umask();
 		if (unlikely(!got_write)) {
 			create_error = -EROFS;
@@ -3683,7 +3683,7 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
 
-	if (!IS_POSIXACL(path.dentry->d_inode))
+	if (!IS_ACL(path.dentry->d_inode))
 		mode &= ~current_umask();
 	error = security_path_mknod(&path, dentry, mode, dev);
 	if (error)
@@ -3754,7 +3754,7 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
 	if (IS_ERR(dentry))
 		return PTR_ERR(dentry);
 
-	if (!IS_POSIXACL(path.dentry->d_inode))
+	if (!IS_ACL(path.dentry->d_inode))
 		mode &= ~current_umask();
 	error = security_path_mkdir(&path, dentry, mode);
 	if (!error)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 2ba0743..41042ce 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1836,6 +1836,12 @@ struct super_operations {
 #define IS_IMMUTABLE(inode)	((inode)->i_flags & S_IMMUTABLE)
 #define IS_POSIXACL(inode)	__IS_FLG(inode, MS_POSIXACL)
 
+#ifdef CONFIG_FS_RICHACL
+#define IS_RICHACL(inode)	__IS_FLG(inode, MS_RICHACL)
+#else
+#define IS_RICHACL(inode)	0
+#endif
+
 #define IS_DEADDIR(inode)	((inode)->i_flags & S_DEAD)
 #define IS_NOCMTIME(inode)	((inode)->i_flags & S_NOCMTIME)
 #define IS_SWAPFILE(inode)	((inode)->i_flags & S_SWAPFILE)
@@ -1854,6 +1860,12 @@ static inline bool HAS_UNMAPPED_ID(struct inode *inode)
 }
 
 /*
+ * IS_ACL() tells the VFS to not apply the umask
+ * and use check_acl for acl permission checks when defined.
+ */
+#define IS_ACL(inode)		__IS_FLG(inode, MS_POSIXACL | MS_RICHACL)
+
+/*
  * Inode state bits.  Protected by inode->i_lock
  *
  * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 36da93f..e77dc61 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -120,7 +120,7 @@ struct inodes_stat_t {
 #define MS_VERBOSE	32768	/* War is peace. Verbosity is silence.
 				   MS_VERBOSE is deprecated. */
 #define MS_SILENT	32768
-#define MS_POSIXACL	(1<<16)	/* VFS does not apply the umask */
+#define MS_POSIXACL	(1<<16)	/* Supports POSIX ACLs */
 #define MS_UNBINDABLE	(1<<17)	/* change to unbindable */
 #define MS_PRIVATE	(1<<18)	/* change to private */
 #define MS_SLAVE	(1<<19)	/* change to slave */
@@ -130,6 +130,7 @@ struct inodes_stat_t {
 #define MS_I_VERSION	(1<<23) /* Update inode I_version field */
 #define MS_STRICTATIME	(1<<24) /* Always perform atime updates */
 #define MS_LAZYTIME	(1<<25) /* Update the on-disk [acm]times lazily */
+#define MS_RICHACL	(1<<26) /* Supports richacls */
 
 /* These sb flags are internal to the kernel */
 #define MS_NOREMOTELOCK	(1<<27)
-- 
2.7.4