security: new security_inode_init_security API adds function callback

This patch changes the security_inode_init_security API by adding a
filesystem specific callback to write security extended attributes.
This change is in preparation for supporting the initialization of
multiple LSM xattrs and the EVM xattr.  Initially the callback function
walks an array of xattrs, writing each xattr separately, but could be
optimized to write multiple xattrs at once.

For existing security_inode_init_security() calls, which have not yet
been converted to use the new callback function, such as those in
reiserfs and ocfs2, this patch defines security_old_inode_init_security().

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>

1 files changed, 20 insertions, 16 deletions

diff --git a/fs/ext4/xattr_security.c b/fs/ext4/xattr_security.c
index 007c3bfbf094..34e4350dd4d9 100644
--- a/fs/ext4/xattr_security.c
+++ b/fs/ext4/xattr_security.c
@@ -48,28 +48,32 @@ ext4_xattr_security_set(struct dentry *dentry, const char *name,
 			      name, value, size, flags);
 }
 
-int
-ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
-		   const struct qstr *qstr)
+int ext4_initxattrs(struct inode *inode, const struct xattr *xattr_array,
+		    void *fs_info)
 {
-	int err;
-	size_t len;
-	void *value;
-	char *name;
+	const struct xattr *xattr;
+	handle_t *handle = fs_info;
+	int err = 0;
 
-	err = security_inode_init_security(inode, dir, qstr, &name, &value, &len);
-	if (err) {
-		if (err == -EOPNOTSUPP)
-			return 0;
-		return err;
+	for (xattr = xattr_array; xattr->name != NULL; xattr++) {
+		err = ext4_xattr_set_handle(handle, inode,
+					    EXT4_XATTR_INDEX_SECURITY,
+					    xattr->name, xattr->value,
+					    xattr->value_len, 0);
+		if (err < 0)
+			break;
 	}
-	err = ext4_xattr_set_handle(handle, inode, EXT4_XATTR_INDEX_SECURITY,
-				    name, value, len, 0);
-	kfree(name);
-	kfree(value);
 	return err;
 }
 
+int
+ext4_init_security(handle_t *handle, struct inode *inode, struct inode *dir,
+		   const struct qstr *qstr)
+{
+	return security_inode_init_security(inode, dir, qstr,
+					    &ext4_initxattrs, handle);
+}
+
 const struct xattr_handler ext4_xattr_security_handler = {
 	.prefix	= XATTR_SECURITY_PREFIX,
 	.list	= ext4_xattr_security_list,