From 3d52ec5e5d0dd7f8ca96a68c6756bd96e58b716b Mon Sep 17 00:00:00 2001 From: Matthias Maennich Date: Fri, 6 Sep 2019 11:32:29 +0100 Subject: [PATCH] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS 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 Reviewed-by: Greg Kroah-Hartman Signed-off-by: Matthias Maennich Signed-off-by: Jessica Yu --- init/Kconfig | 13 +++++++++++++ kernel/module.c | 11 +++++++++-- 2 files changed, 22 insertions(+), 2 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index bd7d650d4a99..cc28561288a7 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -2119,6 +2119,19 @@ config MODULE_COMPRESS_XZ endchoice +config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS + bool "Allow loading of modules with missing namespace imports" + 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(). + There is no technical reason to enforce correct namespace imports, + but it creates consistency between symbols defining namespaces and + users importing namespaces they make use of. This option relaxes this + requirement and lifts the enforcement when loading a module. + + 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 6bb9b938f9c7..f76efcf2043e 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; }