From patchwork Mon Jul 31 08:38:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 13334052 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 48CCBC001DF for ; Mon, 31 Jul 2023 08:39:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=7xHFvHGg35EgVKuIueU8zHVrybfIuzPDNiQNVJWLZUA=; b=cM4lhEgq9WxxcF E8uEXLTz+iK2zk+b2992DegVqbL9OxdU58dCBbslbwM0eYkv/tDjRN7By4jgh4FM3qKw3lfLi6ICh LPYQVFOOH4UrLll1rWkoOek6v3Tz7smrkXExghM+aCHT7SgZ81S8PA6vDpbjfD7ZyMb/Cke/M9/xS HckWZ/Y9MHhn+JQyMMdKhFgCg2aBYwZk4ieZbjqvjOpNb4GlVxOOc5a2KQaNR8DSkFxZjVjWzrpt5 L+LgcvpNcBAtLpq3N8fsmXeG+Id64YRznpRjagT0v5x5VZkOMenhDmgYvAE51hcDwj5GScvvq3LXN zFAyN6aeN8sWXYqCUFFQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qQOQX-00EZ6k-0F; Mon, 31 Jul 2023 08:38:53 +0000 Received: from 2a02-8389-2341-5b80-39d3-4735-9a3c-88d8.cable.dynamic.v6.surfer.at ([2a02:8389:2341:5b80:39d3:4735:9a3c:88d8] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1qQOQ6-00EYvK-1x; Mon, 31 Jul 2023 08:38:26 +0000 From: Christoph Hellwig To: Luis Chamberlain , Greg Kroah-Hartman , Daniel Mack , Haojian Zhuang , Robert Jarzmik , Ulf Hansson , Yangbo Lu , Joshua Kinard Cc: Daniel Vetter , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org (open list), linux-mmc@vger.kernel.org, netdev@vger.kernel.org, linux-rtc@vger.kernel.org, linux-modules@vger.kernel.org Subject: [PATCH 5/5] modules: only allow symbol_get of EXPORT_SYMBOL_GPL modules Date: Mon, 31 Jul 2023 10:38:06 +0200 Message-Id: <20230731083806.453036-6-hch@lst.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230731083806.453036-1-hch@lst.de> References: <20230731083806.453036-1-hch@lst.de> MIME-Version: 1.0 X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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 propriertary modules into an allegedly GPL licensed module and then rexporting them. Given that symbol_get was only ever inteded for tightly cooperating modules using very internal symbols it is logical to restrict it to being used on EXPORY_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 Reviewed-by: Greg Kroah-Hartman --- kernel/module/internal.h | 1 + kernel/module/main.c | 17 ++++++++++++----- 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/kernel/module/internal.h b/kernel/module/internal.h index c8b7b4dcf7820d..add687c2abde8b 100644 --- a/kernel/module/internal.h +++ b/kernel/module/internal.h @@ -93,6 +93,7 @@ struct find_symbol_arg { /* Input */ const char *name; bool gplok; + bool gplonly; bool warn; /* Output */ diff --git a/kernel/module/main.c b/kernel/module/main.c index 59b1d067e52890..85d3f00ca65758 100644 --- a/kernel/module/main.c +++ b/kernel/module/main.c @@ -281,6 +281,8 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms, if (!fsa->gplok && syms->license == GPL_ONLY) return false; + if (fsa->gplonly && syms->license != GPL_ONLY) + return false; sym = bsearch(fsa->name, syms->start, syms->stop - syms->start, sizeof(struct kernel_symbol), cmp_name); @@ -776,8 +778,9 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, void __symbol_put(const char *symbol) { struct find_symbol_arg fsa = { - .name = symbol, - .gplok = true, + .name = symbol, + .gplok = true, + .gplonly = true, }; preempt_disable(); @@ -1289,14 +1292,18 @@ static void free_module(struct module *mod) void *__symbol_get(const char *symbol) { struct find_symbol_arg fsa = { - .name = symbol, - .gplok = true, - .warn = true, + .name = symbol, + .gplok = true, + .gplonly = true, + .warn = true, }; preempt_disable(); if (!find_symbol(&fsa) || strong_try_module_get(fsa.owner)) { preempt_enable(); + if (fsa.gplonly) + pr_warn("failing symbol_get of non-GPLONLY symbol %s.\n", + symbol); return NULL; } preempt_enable();