From 51161bfc66a68d21f13d15a689b3ea7980457790 Mon Sep 17 00:00:00 2001
From: Leon Romanovsky <leonro@mellanox.com>
Date: Sun, 19 Apr 2020 18:55:06 +0300
Subject: [PATCH] kernel/module: Hide vermagic header file from general use
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VERMAGIC* definitions are not supposed to be used by the drivers,
see this [1] bug report, so introduce special define to guard inclusion
of this header file and define it in kernel/modules.h and in internal
script that generates *.mod.c files.
In-tree module build:
➜ kernel git:(vermagic) ✗ make clean
➜ kernel git:(vermagic) ✗ make M=drivers/infiniband/hw/mlx5
➜ kernel git:(vermagic) ✗ modinfo drivers/infiniband/hw/mlx5/mlx5_ib.ko
filename: /images/leonro/src/kernel/drivers/infiniband/hw/mlx5/mlx5_ib.ko
<...>
vermagic: 5.6.0+ SMP mod_unload modversions
Out-of-tree module build:
➜ mlx5 make -C /images/leonro/src/kernel clean M=/tmp/mlx5
➜ mlx5 make -C /images/leonro/src/kernel M=/tmp/mlx5
➜ mlx5 modinfo /tmp/mlx5/mlx5_ib.ko
filename: /tmp/mlx5/mlx5_ib.ko
<...>
vermagic: 5.6.0+ SMP mod_unload modversions
[1] https://lore.kernel.org/lkml/20200411155623.GA22175@zn.tnic
Reported-by: Borislav Petkov <bp@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Jessica Yu <jeyu@kernel.org>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/linux/vermagic.h | 5 +++++
kernel/module.c | 3 +++
scripts/mod/modpost.c | 1 +
3 files changed, 9 insertions(+)
diff --git a/include/linux/vermagic.h b/include/linux/vermagic.h
index 9aced11e9000..7768d20ada39 100644
--- a/include/linux/vermagic.h
+++ b/include/linux/vermagic.h
@@ -1,4 +1,9 @@
/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef INCLUDE_VERMAGIC
+#error "This header can be included from kernel/module.c or *.mod.c only"
+#endif
+
#include <generated/utsrelease.h>
/* Simply sanity version stamp for modules. */
diff --git a/kernel/module.c b/kernel/module.c
index 646f1e2330d2..8833e848b73c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -4,6 +4,9 @@
Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
*/
+
+#define INCLUDE_VERMAGIC
+
#include <linux/export.h>
#include <linux/extable.h>
#include <linux/moduleloader.h>
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 5c3c50c5ec52..7f7d4ee7b652 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -2251,6 +2251,7 @@ static void add_header(struct buffer *b, struct module *mod)
* Include build-salt.h after module.h in order to
* inherit the definitions.
*/
+ buf_printf(b, "#define INCLUDE_VERMAGIC\n");
buf_printf(b, "#include <linux/build-salt.h>\n");
buf_printf(b, "#include <linux/vermagic.h>\n");
buf_printf(b, "#include <linux/compiler.h>\n");