[patch 1/4] vfs: utimes: move owner check into inode_change_ok()

Add a new ia_valid flag: ATTR_TIMES_SET, to handle the
UTIMES_OMIT/UTIMES_NOW and UTIMES_NOW/UTIMES_OMIT cases.  In these
cases neither ATTR_MTIME_SET nor ATTR_ATIME_SET is in the flags, yet
the POSIX draft specifies that permission checking is performed the
same way as if one or both of the times was explicitly set to a
timestamp.

See the path "vfs: utimensat(): fix error checking for
{UTIME_NOW,UTIME_OMIT} case" by Michael Kerrisk for the patch
introducing this behavior.

This is a cleanup, as well as allowing filesystems (NFS/fuse/...) to
perform their own permission checking instead of the default.

CC: Ulrich Drepper <drepper@redhat.com>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 17 insertions, 16 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index d8721e818b45..527b9e482f99 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -320,22 +320,23 @@ typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
  * Attribute flags.  These should be or-ed together to figure out what
  * has been changed!
  */
-#define ATTR_MODE       1
-#define ATTR_UID        2
-#define ATTR_GID        4
-#define ATTR_SIZE       8
-#define ATTR_ATIME      16
-#define ATTR_MTIME      32
-#define ATTR_CTIME      64
-#define ATTR_ATIME_SET  128
-#define ATTR_MTIME_SET  256
-#define ATTR_FORCE      512     /* Not a change, but a change it */
-#define ATTR_ATTR_FLAG  1024
-#define ATTR_KILL_SUID  2048
-#define ATTR_KILL_SGID  4096
-#define ATTR_FILE       8192
-#define ATTR_KILL_PRIV  16384
-#define ATTR_OPEN       32768   /* Truncating from open(O_TRUNC) */
+#define ATTR_MODE       (1 << 0)
+#define ATTR_UID        (1 << 1)
+#define ATTR_GID        (1 << 2)
+#define ATTR_SIZE       (1 << 3)
+#define ATTR_ATIME      (1 << 4)
+#define ATTR_MTIME      (1 << 5)
+#define ATTR_CTIME      (1 << 6)
+#define ATTR_ATIME_SET  (1 << 7)
+#define ATTR_MTIME_SET  (1 << 8)
+#define ATTR_FORCE      (1 << 9) /* Not a change, but a change it */
+#define ATTR_ATTR_FLAG  (1 << 10)
+#define ATTR_KILL_SUID  (1 << 11)
+#define ATTR_KILL_SGID  (1 << 12)
+#define ATTR_FILE       (1 << 13)
+#define ATTR_KILL_PRIV  (1 << 14)
+#define ATTR_OPEN       (1 << 15) /* Truncating from open(O_TRUNC) */
+#define ATTR_TIMES_SET  (1 << 16)
 
 /*
  * This is the Inode Attributes structure, used for notify_change().  It