This is a note to let you know that I've just added the patch titled
modules: only allow symbol_get of EXPORT_SYMBOL_GPL modules
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
modules-only-allow-symbol_get-of-export_symbol_gpl-modules.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9011e49d54dcc7653ebb8a1e05b5badb5ecfa9f9 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@xxxxxx>
Date: Tue, 1 Aug 2023 19:35:44 +0200
Subject: modules: only allow symbol_get of EXPORT_SYMBOL_GPL modules
From: Christoph Hellwig <hch@xxxxxx>
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@xxxxxx>
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
Patches currently in stable-queue which might be from hch@xxxxxx are
queue-5.4/mmc-au1xmmc-force-non-modular-build-and-remove-symbol_get-usage.patch
queue-5.4/net-enetc-use-export_symbol_gpl-for-enetc_phc_index.patch
queue-5.4/modules-only-allow-symbol_get-of-export_symbol_gpl-modules.patch
queue-5.4/rtc-ds1685-use-export_symbol_gpl-for-ds1685_rtc_poweroff.patch
queue-5.4/arm-pxa-remove-use-of-symbol_get.patch
