From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vs1-f74.google.com ([209.85.217.74]:49203 "EHLO mail-vs1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728019AbfHMMT1 (ORCPT ); Tue, 13 Aug 2019 08:19:27 -0400 Received: by mail-vs1-f74.google.com with SMTP id b19so28941682vsq.16 for ; Tue, 13 Aug 2019 05:19:27 -0700 (PDT) Date: Tue, 13 Aug 2019 13:17:02 +0100 In-Reply-To: <20190813121733.52480-1-maennich@google.com> Message-Id: <20190813121733.52480-6-maennich@google.com> Mime-Version: 1.0 References: <20180716122125.175792-1-maco@android.com> <20190813121733.52480-1-maennich@google.com> Subject: [PATCH v2 05/10] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS From: Matthias Maennich Content-Type: text/plain; charset="UTF-8" Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, maco@android.com Cc: kernel-team@android.com, maennich@google.com, arnd@arndb.de, geert@linux-m68k.org, gregkh@linuxfoundation.org, hpa@zytor.com, jeyu@kernel.org, joel@joelfernandes.org, kstewart@linuxfoundation.org, linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-modules@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, lucas.de.marchi@gmail.com, maco@google.com, michal.lkml@markovi.net, mingo@redhat.com, oneukum@suse.com, pombredanne@nexb.com, sam@ravnborg.org, sboyd@codeaurora.org, sspatil@google.com, stern@rowland.harvard.edu, tglx@linutronix.de, usb-storage@lists.one-eyed-alien.net, x86@kernel.org, yamada.masahiro@socionext.com, Andrew Morton , Johannes Weiner , "Peter Zijlstra (Intel)" , Mauro Carvalho Chehab , David Howells , Patrick Bellasi , Dan Williams , Adrian Reber , Richard Guy Briggs If MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS is enabled (default=n), the requirement for modules to import all namespaces that are used by the module is relaxed. Enabling this option effectively allows (invalid) modules to be loaded while only a warning is emitted. Disabling this option keeps the enforcement at module loading time and loading is denied if the module's imports are not satisfactory. Reviewed-by: Martijn Coenen Signed-off-by: Matthias Maennich --- init/Kconfig | 14 ++++++++++++++ kernel/module.c | 11 +++++++++-- 2 files changed, 23 insertions(+), 2 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index bd7d650d4a99..b3373334cdf1 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2119,6 +2119,20 @@ config MODULE_COMPRESS_XZ endchoice +config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS + bool "Allow loading of modules with missing namespace imports" + default n + help + Symbols exported with EXPORT_SYMBOL_NS*() are considered exported in + a namespace. A module that makes use of a symbol exported with such a + namespace is required to import the namespace via MODULE_IMPORT_NS(). + This option relaxes this requirement when loading a module. While + technically there is no reason to enforce correct namespace imports, + it creates consistency between symbols defining namespaces and users + importing namespaces they make use of. + + If unsure, say N. + config TRIM_UNUSED_KSYMS bool "Trim unused exported kernel symbols" depends on MODULES && !UNUSED_SYMBOLS diff --git a/kernel/module.c b/kernel/module.c index 57e8253f2251..7c934aaae2d3 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1408,9 +1408,16 @@ static int verify_namespace_is_imported(const struct load_info *info, imported_namespace = get_next_modinfo( info, "import_ns", imported_namespace); } - pr_err("%s: module uses symbol (%s) from namespace %s, but does not import it.\n", - mod->name, kernel_symbol_name(sym), namespace); +#ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS + pr_warn( +#else + pr_err( +#endif + "%s: module uses symbol (%s) from namespace %s, but does not import it.\n", + mod->name, kernel_symbol_name(sym), namespace); +#ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS return -EINVAL; +#endif } return 0; } -- 2.23.0.rc1.153.gdeed80330f-goog