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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham 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 8AF1FC33CB1 for ; Thu, 16 Jan 2020 11:03:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6687920730 for ; Thu, 16 Jan 2020 11:03:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726151AbgAPLDJ (ORCPT ); Thu, 16 Jan 2020 06:03:09 -0500 Received: from Chamillionaire.breakpoint.cc ([193.142.43.52]:33928 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725800AbgAPLDI (ORCPT ); Thu, 16 Jan 2020 06:03:08 -0500 Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1is2va-0004LU-In; Thu, 16 Jan 2020 12:03:06 +0100 From: Florian Westphal To: Cc: syzkaller-bugs@googlegroups.com, , Florian Westphal , syzbot+37a6804945a3a13b1572@syzkaller.appspotmail.com Subject: [PATCH nf] netfilter: nf_tables: fix flowtable list del corruption Date: Thu, 16 Jan 2020 12:03:01 +0100 Message-Id: <20200116110301.4875-1-fw@strlen.de> X-Mailer: git-send-email 2.24.1 In-Reply-To: <000000000000b3599c059c36db0d@google.com> References: <000000000000b3599c059c36db0d@google.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org syzbot reported following crash: list_del corruption, ffff88808c9bb000->prev is LIST_POISON2 (dead000000000122) [..] Call Trace: __list_del_entry include/linux/list.h:131 [inline] list_del_rcu include/linux/rculist.h:148 [inline] nf_tables_commit+0x1068/0x3b30 net/netfilter/nf_tables_api.c:7183 [..] The commit transaction list has: NFT_MSG_NEWTABLE NFT_MSG_NEWFLOWTABLE NFT_MSG_DELFLOWTABLE NFT_MSG_DELTABLE A missing generation check during DELTABLE processing causes it to queue the DELFLOWTABLE operation a second time, so we corrupt the list here: case NFT_MSG_DELFLOWTABLE: list_del_rcu(&nft_trans_flowtable(trans)->list); nf_tables_flowtable_notify(&trans->ctx, because we have two different DELFLOWTABLE transactions for the same flowtable. We then call list_del_rcu() twice for the same flowtable->list. The object handling seems to suffer from the same bug so add a generation check too and only queue delete transactions for flowtables/objects that are still active in the next generation. Reported-by: syzbot+37a6804945a3a13b1572@syzkaller.appspotmail.com Fixes: 3b49e2e94e6eb ("netfilter: nf_tables: add flow table netlink frontend") Signed-off-by: Florian Westphal --- net/netfilter/nf_tables_api.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 5a1a6632e3a6..9ba1747686ed 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -1047,12 +1047,18 @@ static int nft_flush_table(struct nft_ctx *ctx) } list_for_each_entry_safe(flowtable, nft, &ctx->table->flowtables, list) { + if (!nft_is_active_next(ctx->net, flowtable)) + continue; + err = nft_delflowtable(ctx, flowtable); if (err < 0) goto out; } list_for_each_entry_safe(obj, ne, &ctx->table->objects, list) { + if (!nft_is_active_next(ctx->net, obj)) + continue; + err = nft_delobj(ctx, obj); if (err < 0) goto out; -- 2.24.1