modules: inherit TAINT_PROPRIETARY_MODULE
If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the taint flag
for all modules importing these symbols, and don't allow loading
symbols from TAINT_PROPRIETARY_MODULE modules if the module previously
imported gplonly symbols. Add a anti-circumvention devices so people
don't accidentally get themselves into trouble this way.
Comment from Greg:
"Ah, the proven-to-be-illegal "GPL Condom" defense :)"
[jeyu: pr_info -> pr_err and pr_warn as per discussion]
Link: http://lore.kernel.org/r/20200730162957.GA22469@lst.de
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
diff --git a/kernel/module.c b/kernel/module.c
index 656f5ff..09bf5a6 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1431,6 +1431,24 @@
return 0;
}
+static bool inherit_taint(struct module *mod, struct module *owner)
+{
+ if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
+ return true;
+
+ if (mod->using_gplonly_symbols) {
+ pr_err("%s: module using GPL-only symbols uses symbols from proprietary module %s.\n",
+ mod->name, owner->name);
+ return false;
+ }
+
+ if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
+ pr_warn("%s: module uses symbols from proprietary module %s, inheriting taint.\n",
+ mod->name, owner->name);
+ set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints);
+ }
+ return true;
+}
/* Resolve a symbol for this module. I.e. if we find one, record usage. */
static const struct kernel_symbol *resolve_symbol(struct module *mod,
@@ -1456,6 +1474,14 @@
if (!sym)
goto unlock;
+ if (license == GPL_ONLY)
+ mod->using_gplonly_symbols = true;
+
+ if (!inherit_taint(mod, owner)) {
+ sym = NULL;
+ goto getname;
+ }
+
if (!check_version(info, name, mod, crc)) {
sym = ERR_PTR(-EINVAL);
goto getname;