evm: posix acls modify i_mode

The posix xattr acls are 'system' prefixed, which normally would not
affect security.evm.  An interesting side affect of writing posix xattr
acls is their modifying of the i_mode, which is included in security.evm.

This patch updates security.evm when posix xattr acls are written.

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

include/linux/evm.h

@@ -33,6 +33,14 @@ extern void evm_inode_post_removexattr(struct dentry *dentry,
 extern int evm_inode_init_security(struct inode *inode,
 				   const struct xattr *xattr_array,
 				   struct xattr *evm);
+#ifdef CONFIG_FS_POSIX_ACL
+extern int posix_xattr_acl(const char *xattrname);
+#else
+static inline int posix_xattr_acl(const char *xattrname)
+{
+	return 0;
+}
+#endif
 #else
 #ifdef CONFIG_INTEGRITY
 static inline enum integrity_status evm_verifyxattr(struct dentry *dentry,