summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMatthias Maennich <maennich@google.com>2019-09-06 13:32:29 +0300
committerJessica Yu <jeyu@kernel.org>2019-09-10 11:30:27 +0300
commit3d52ec5e5d0dd7f8ca96a68c6756bd96e58b716b (patch)
tree51b5da97980203a40b9b1393ec5da9157d4d3215
parentcb9b55d21fe06ca5e4ba244bb5aac0afeb745c8e (diff)
downloadlinux-3d52ec5e5d0dd7f8ca96a68c6756bd96e58b716b.tar.xz
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>
-rw-r--r--init/Kconfig13
-rw-r--r--kernel/module.c11
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;
}