o Introduce an extended attribute backing file header magic number

o Introduce an extended attribute backing file header version number

2 files changed, 20 insertions, 3 deletions

diff --git a/sys/ufs/ufs/extattr.h b/sys/ufs/ufs/extattr.h
index 6f3132b..c2d1eee 100644
--- a/sys/ufs/ufs/extattr.h
+++ b/sys/ufs/ufs/extattr.h
@@ -32,8 +32,10 @@
 #ifndef _UFS_UFS_EXTATTR_H_
 #define	_UFS_UFS_EXTATTR_H_
 
-#define	UFS_EXTATTR_FSROOTSUBDIR	".attributes"
-#define	UFS_EXTATTR_MAXEXTATTRNAME	33	/* including null */
+#define	UFS_EXTATTR_MAGIC		0x00b5d5ec
+#define	UFS_EXTATTR_VERSION		0x00000002
+#define	UFS_EXTATTR_FSROOTSUBDIR	".attribute"
+#define	UFS_EXTATTR_MAXEXTATTRNAME	65	/* including null */
 #define	UFS_EXTATTR_MAXEXTATTRSIZE	1024	/* bytes */
 
 #define	UFS_EXTATTR_ATTR_FLAG_INUSE	0x00000001	/* attr has been set */
@@ -51,6 +53,8 @@
 #define	UFS_EXTATTR_CMD_DISABLE		0x00000004
 
 struct ufs_extattr_fileheader {
+	u_int	uef_magic;	/* magic number for sanity checking */
+	u_int	uef_version;	/* version of attribute file */
 	u_int	uef_size;	/* size of attributes, w/o header */
 	u_int	uef_read_perm;	/* permissions to read attribute */
 	u_int	uef_write_perm;	/* permissions to write attribute */
diff --git a/sys/ufs/ufs/ufs_extattr.c b/sys/ufs/ufs/ufs_extattr.c
index b12f062..e5155dd 100644
--- a/sys/ufs/ufs/ufs_extattr.c
+++ b/sys/ufs/ufs/ufs_extattr.c
@@ -222,7 +222,6 @@ ufs_extattr_enable(struct ufsmount *ump, char *attrname,
 	    sizeof(struct ufs_extattr_fileheader));
 	
 	attribute->uele_backing_vnode = backing_vnode;
-	backing_vnode->v_flag |= VSYSTEM;
 
 	auio.uio_iov = &aiov;
 	auio.uio_iovcnt = 1;
@@ -249,6 +248,20 @@ ufs_extattr_enable(struct ufsmount *ump, char *attrname,
 		goto free_exit;
 	}
 
+	if (attribute->uele_fileheader.uef_magic != UFS_EXTATTR_MAGIC) {
+		printf("ufs_extattr_enable: invalid attribute header magic\n");
+		error = EINVAL;
+		goto free_exit;
+	}
+
+	if (attribute->uele_fileheader.uef_version != UFS_EXTATTR_VERSION) {
+		printf("ufs_extattr_enable: incorrect attribute header "
+		    "version\n");
+		error = EINVAL;
+		goto free_exit;
+	}
+
+	backing_vnode->v_flag |= VSYSTEM;
 	LIST_INSERT_HEAD(&ump->um_extattr.uepm_list, attribute, uele_entries);
 
 	return (0);