From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 72CBDC43603 for ; Tue, 17 Dec 2019 00:55:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4339B206D3 for ; Tue, 17 Dec 2019 00:55:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728005AbfLQAyq (ORCPT ); Mon, 16 Dec 2019 19:54:46 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:35474 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727150AbfLQAvo (ORCPT ); Mon, 16 Dec 2019 19:51:44 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1ih15L-0003MA-Dg; Tue, 17 Dec 2019 00:51:35 +0000 Received: from ben by deadeye with local (Exim 4.93-RC7) (envelope-from ) id 1ih15K-0005d0-La; Tue, 17 Dec 2019 00:51:34 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Pablo Neira Ayuso" , "Lukas Wunner" Date: Tue, 17 Dec 2019 00:47:30 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 116/136] netfilter: nf_tables: Align nft_expr private data to 64-bit In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.80-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Lukas Wunner commit 250367c59e6ba0d79d702a059712d66edacd4a1a upstream. Invoking the following commands on a 32-bit architecture with strict alignment requirements (such as an ARMv7-based Raspberry Pi) results in an alignment exception: # nft add table ip test-ip4 # nft add chain ip test-ip4 output { type filter hook output priority 0; } # nft add rule ip test-ip4 output quota 1025 bytes Alignment trap: not handling instruction e1b26f9f at [<7f4473f8>] Unhandled fault: alignment exception (0x001) at 0xb832e824 Internal error: : 1 [#1] PREEMPT SMP ARM Hardware name: BCM2835 [<7f4473fc>] (nft_quota_do_init [nft_quota]) [<7f447448>] (nft_quota_init [nft_quota]) [<7f4260d0>] (nf_tables_newrule [nf_tables]) [<7f4168dc>] (nfnetlink_rcv_batch [nfnetlink]) [<7f416bd0>] (nfnetlink_rcv [nfnetlink]) [<8078b334>] (netlink_unicast) [<8078b664>] (netlink_sendmsg) [<8071b47c>] (sock_sendmsg) [<8071bd18>] (___sys_sendmsg) [<8071ce3c>] (__sys_sendmsg) [<8071ce94>] (sys_sendmsg) The reason is that nft_quota_do_init() calls atomic64_set() on an atomic64_t which is only aligned to 32-bit, not 64-bit, because it succeeds struct nft_expr in memory which only contains a 32-bit pointer. Fix by aligning the nft_expr private data to 64-bit. Fixes: 96518518cc41 ("netfilter: add nftables") Signed-off-by: Lukas Wunner Signed-off-by: Pablo Neira Ayuso Signed-off-by: Ben Hutchings --- include/net/netfilter/nf_tables.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -364,7 +364,8 @@ struct nft_expr_ops { */ struct nft_expr { const struct nft_expr_ops *ops; - unsigned char data[]; + unsigned char data[] + __attribute__((aligned(__alignof__(u64)))); }; static inline void *nft_expr_priv(const struct nft_expr *expr)