+++ Christoph Hellwig [30/07/20 08:10 +0200]:
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 :)
Signed-off-by: Christoph Hellwig <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
---
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 30b0f5fcdb3c37..e30ed5fa33a738 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 afb2bfdd5134b3..04f993863ae417 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 (license == 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);
+ }
Sorry that I didn't think of this yesterday, but I'm wondering if we
should print a warning before add_taint_module(). Maybe something
along the lines of, "%s: module uses symbols from proprietary module
%s, inheriting taint.", with %s being mod->name, owner->name. We can
check mod->taints for TAINT_PROPRIETARY_MODULE and print the warning once.
Additionally, maybe it's a good idea to print an error before goto
getname (e.g., "%s: module using GPL-only symbols uses symbols from
proprietary module %s."), so one would know why the module load
failed, right now this manifests itself as an unknown symbol error.
Otherwise, this patchset looks good to me and I agree with it in
principle. Thanks Christoph!
