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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 D2721C468BD for ; Sat, 8 Jun 2019 11:55:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ACD4A21537 for ; Sat, 8 Jun 2019 11:55:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559994936; bh=Anl24wVRwQz/64PnpnLUW8+rHvTzsBxXk1v9M9lAXgQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BvUg9vyxSAgg68eapm/dZL77d1hQRoRh0uXjALINC7KlvSMP2RCnBlLUGa+/yiHaI tbPIxZAxyK6Bz2bIt3k5Kl4ae5c44ypAT9s4Uyx7OiyowMUjRf2HRkKcu+2D2AOG7o dAry5ixDhOxpfQy/aJWSQB/+UOfPv8ZVxaWCuvPQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727987AbfFHLz1 (ORCPT ); Sat, 8 Jun 2019 07:55:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:57122 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727243AbfFHLkD (ORCPT ); Sat, 8 Jun 2019 07:40:03 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5B1AE214C6; Sat, 8 Jun 2019 11:40:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1559994002; bh=Anl24wVRwQz/64PnpnLUW8+rHvTzsBxXk1v9M9lAXgQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eyTqEfRTZJS8+Vy407O46uKdqO/Xl6xz2WPeM/XhiPSwRX6L/DQS3ciAtMFCpbbfI XiUbdhux9TJCTSWdVbs/ZC/VeohO0dIaHaQv8w8N2N0idNrqIeaOFefYw2B0gfVDiu PCHdLUtYlVVnUSGglJ5OnbuM42TBxwZjI52oDUOM= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Florian Westphal , Pablo Neira Ayuso , Sasha Levin , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.1 09/70] netfilter: nf_tables: fix oops during rule dump Date: Sat, 8 Jun 2019 07:38:48 -0400 Message-Id: <20190608113950.8033-9-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190608113950.8033-1-sashal@kernel.org> References: <20190608113950.8033-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Florian Westphal [ Upstream commit 2c82c7e724ff51cab78e1afd5c2aaa31994fe41e ] We can oops in nf_tables_fill_rule_info(). Its not possible to fetch previous element in rcu-protected lists when deletions are not prevented somehow: list_del_rcu poisons the ->prev pointer value. Before rcu-conversion this was safe as dump operations did hold nfnetlink mutex. Pass previous rule as argument, obtained by keeping a pointer to the previous rule during traversal. Fixes: d9adf22a291883 ("netfilter: nf_tables: use call_rcu in netlink dumps") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nf_tables_api.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 1606eaa5ae0d..041a81185c6a 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -2256,13 +2256,13 @@ static int nf_tables_fill_rule_info(struct sk_buff *skb, struct net *net, u32 flags, int family, const struct nft_table *table, const struct nft_chain *chain, - const struct nft_rule *rule) + const struct nft_rule *rule, + const struct nft_rule *prule) { struct nlmsghdr *nlh; struct nfgenmsg *nfmsg; const struct nft_expr *expr, *next; struct nlattr *list; - const struct nft_rule *prule; u16 type = nfnl_msg_type(NFNL_SUBSYS_NFTABLES, event); nlh = nlmsg_put(skb, portid, seq, type, sizeof(struct nfgenmsg), flags); @@ -2282,8 +2282,7 @@ static int nf_tables_fill_rule_info(struct sk_buff *skb, struct net *net, NFTA_RULE_PAD)) goto nla_put_failure; - if ((event != NFT_MSG_DELRULE) && (rule->list.prev != &chain->rules)) { - prule = list_prev_entry(rule, list); + if (event != NFT_MSG_DELRULE && prule) { if (nla_put_be64(skb, NFTA_RULE_POSITION, cpu_to_be64(prule->handle), NFTA_RULE_PAD)) @@ -2330,7 +2329,7 @@ static void nf_tables_rule_notify(const struct nft_ctx *ctx, err = nf_tables_fill_rule_info(skb, ctx->net, ctx->portid, ctx->seq, event, 0, ctx->family, ctx->table, - ctx->chain, rule); + ctx->chain, rule, NULL); if (err < 0) { kfree_skb(skb); goto err; @@ -2355,12 +2354,13 @@ static int __nf_tables_dump_rules(struct sk_buff *skb, const struct nft_chain *chain) { struct net *net = sock_net(skb->sk); + const struct nft_rule *rule, *prule; unsigned int s_idx = cb->args[0]; - const struct nft_rule *rule; + prule = NULL; list_for_each_entry_rcu(rule, &chain->rules, list) { if (!nft_is_active(net, rule)) - goto cont; + goto cont_skip; if (*idx < s_idx) goto cont; if (*idx > s_idx) { @@ -2372,11 +2372,13 @@ static int __nf_tables_dump_rules(struct sk_buff *skb, NFT_MSG_NEWRULE, NLM_F_MULTI | NLM_F_APPEND, table->family, - table, chain, rule) < 0) + table, chain, rule, prule) < 0) return 1; nl_dump_check_consistent(cb, nlmsg_hdr(skb)); cont: + prule = rule; +cont_skip: (*idx)++; } return 0; @@ -2532,7 +2534,7 @@ static int nf_tables_getrule(struct net *net, struct sock *nlsk, err = nf_tables_fill_rule_info(skb2, net, NETLINK_CB(skb).portid, nlh->nlmsg_seq, NFT_MSG_NEWRULE, 0, - family, table, chain, rule); + family, table, chain, rule, NULL); if (err < 0) goto err; -- 2.20.1