ovl: move super block magic number to magic.h

Orabug: 26546379, 26540706
CVE-2016-1575
CVE-2016-1576

The overlayfs file system is not recognized by programs
like tail because the magic number is not in standard header location.

Move it so that the value will propagate on for the GNU library
and utilities. Needs to go in the fstatfs manual page as well.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
(cherry picked from commit 257f871993474e2bde6c497b54022c362cf398e1)
Signed-off-by: Somasundaram Krishnasamy <somasundaram.krishnasamy@oracle.com>
Reviewed-by: Jack Vogel <jack.vogel@oracle.com>

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 2ef8ea14fdad8d99c83342b328177909e8334d44..6ecc07c3e795c4eb3d9a325f99c56baf0e253e8f 100644 (file)
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -25,8 +25,6 @@ MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
 MODULE_DESCRIPTION("Overlay filesystem");
 MODULE_LICENSE("GPL");
 
-#define OVERLAYFS_SUPER_MAGIC 0x794c7630
-
 struct ovl_config {
        char *lowerdir;
        char *upperdir;

diff --git a/include/uapi/linux/magic.h b/include/uapi/linux/magic.h
index 7b1425a6b370f878b7e08de24a5d901d6187d0e2..eec438952aa78f93b7dbce831fe4b10e1bf62e74 100644 (file)
--- a/include/uapi/linux/magic.h
+++ b/include/uapi/linux/magic.h
@@ -31,6 +31,7 @@
 #define PSTOREFS_MAGIC         0x6165676C
 #define EFIVARFS_MAGIC         0xde5e81e4
 #define HOSTFS_SUPER_MAGIC     0x00c0ffee
+#define OVERLAYFS_SUPER_MAGIC  0x794c7630
 
 #define MINIX_SUPER_MAGIC      0x137F          /* minix v1 fs, 14 char names */
 #define MINIX_SUPER_MAGIC2     0x138F          /* minix v1 fs, 30 char names */