5.4-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Hellwig hch@lst.de
commit 9011e49d54dcc7653ebb8a1e05b5badb5ecfa9f9 upstream.
It has recently come to my attention that nvidia is circumventing the protection added in 262e6ae7081d ("modules: inherit TAINT_PROPRIETARY_MODULE") by importing exports from their proprietary modules into an allegedly GPL licensed module and then rexporting them.
Given that symbol_get was only ever intended for tightly cooperating modules using very internal symbols it is logical to restrict it to being used on EXPORT_SYMBOL_GPL and prevent nvidia from costly DMCA Circumvention of Access Controls law suites.
All symbols except for four used through symbol_get were already exported as EXPORT_SYMBOL_GPL, and the remaining four ones were switched over in the preparation patches.
Fixes: 262e6ae7081d ("modules: inherit TAINT_PROPRIETARY_MODULE") Signed-off-by: Christoph Hellwig hch@lst.de Reviewed-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Luis Chamberlain mcgrof@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/module.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
--- a/kernel/module.c +++ b/kernel/module.c @@ -2291,15 +2291,26 @@ static void free_module(struct module *m void *__symbol_get(const char *symbol) { struct module *owner; + enum mod_license license; const struct kernel_symbol *sym;
preempt_disable(); - sym = find_symbol(symbol, &owner, NULL, NULL, true, true); - if (sym && strong_try_module_get(owner)) + sym = find_symbol(symbol, &owner, NULL, &license, true, true); + if (!sym) + goto fail; + if (license != GPL_ONLY) { + pr_warn("failing symbol_get of non-GPLONLY symbol %s.\n", + symbol); + goto fail; + } + if (strong_try_module_get(owner)) sym = NULL; preempt_enable();
return sym ? (void *)kernel_symbol_value(sym) : NULL; +fail: + preempt_enable(); + return NULL; } EXPORT_SYMBOL_GPL(__symbol_get);