[PATCH 7/7] modules: inherit TAINT_PROPRIETARY_MODULE

[Christoph Hellwig]

If a TAINT_PROPRIETARY_MODULE exports symbol, inherit the tain 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.

Signed-off-by: Christoph Hellwig <h...@lst.de>
---
 include/linux/module.h |  1 +
 kernel/module.c        | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/include/linux/module.h b/include/linux/module.h
index c9bc3412ae4465..d49e033563dadf 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -389,6 +389,7 @@ struct module {
        unsigned int num_gpl_syms;
        const struct kernel_symbol *gpl_syms;
        const s32 *gpl_crcs;
+       bool using_gplonly_symbols;
 
 #ifdef CONFIG_UNUSED_SYMBOLS
        /* unused exported symbols. */
diff --git a/kernel/module.c b/kernel/module.c
index a907bc57d343f9..eb6ab2f4b81aaa 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1456,6 +1456,18 @@ static const struct kernel_symbol *resolve_symbol(struct 
module *mod,
        if (!sym)
                goto unlock;
 
+       if (licence == GPL_ONLY)
+               mod->using_gplonly_symbols = true;
+
+       if (owner && test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints)) {
+               if (mod->using_gplonly_symbols) {
+                       sym = NULL;
+                       goto getname;
+               }
+               add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
+                                LOCKDEP_NOW_UNRELIABLE);
+       }
+
        if (!check_version(info, name, mod, crc)) {
                sym = ERR_PTR(-EINVAL);
                goto getname;
-- 
2.27.0