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 <maco@android.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
This commit is contained in:
Matthias Maennich 2019-09-06 11:32:29 +01:00 committed by Jessica Yu
parent cb9b55d21f
commit 3d52ec5e5d
2 changed files with 22 additions and 2 deletions

View File

@ -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

View File

@ -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;
}