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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,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 053ADC4360F for ; Mon, 11 Mar 2019 22:50:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D0F7C2087C for ; Mon, 11 Mar 2019 22:50:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726639AbfCKWux (ORCPT ); Mon, 11 Mar 2019 18:50:53 -0400 Received: from mail.us.es ([193.147.175.20]:34590 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726446AbfCKWup (ORCPT ); Mon, 11 Mar 2019 18:50:45 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id C61D120991B for ; Mon, 11 Mar 2019 23:50:43 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id B30D8DA47A for ; Mon, 11 Mar 2019 23:50:43 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id A5989DA449; Mon, 11 Mar 2019 23:50:43 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 73A8ADA856; Mon, 11 Mar 2019 23:50:41 +0100 (CET) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Mon, 11 Mar 2019 23:50:41 +0100 (CET) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from salvia.here (sys.soleta.eu [212.170.55.40]) (Authenticated sender: pneira@us.es) by entrada.int (Postfix) with ESMTPA id 44D954265A2F; Mon, 11 Mar 2019 23:50:41 +0100 (CET) X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org Subject: [PATCH 2/5] netfilter: nf_tables: fix set double-free in abort path Date: Mon, 11 Mar 2019 23:50:32 +0100 Message-Id: <20190311225035.21250-3-pablo@netfilter.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190311225035.21250-1-pablo@netfilter.org> References: <20190311225035.21250-1-pablo@netfilter.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org The abort path can cause a double-free of an anonymous set. Added-and-to-be-aborted rule looks like this: udp dport { 137, 138 } drop The to-be-aborted transaction list looks like this: newset newsetelem newsetelem rule This gets walked in reverse order, so first pass disables the rule, the set elements, then the set. After synchronize_rcu(), we then destroy those in same order: rule, set element, set element, newset. Problem is that the anonymous set has already been bound to the rule, so the rule (lookup expression destructor) already frees the set, when then cause use-after-free when trying to delete the elements from this set, then try to free the set again when handling the newset expression. Rule releases the bound set in first place from the abort path, this causes the use-after-free on set element removal when undoing the new element transactions. To handle this, skip new element transaction if set is bound from the abort path. This is still causes the use-after-free on set element removal. To handle this, remove transaction from the list when the set is already bound. Joint work with Florian Westphal. Fixes: f6ac85858976 ("netfilter: nf_tables: unbind set in rule from commit path") Bugzilla: https://bugzilla.netfilter.org/show_bug.cgi?id=1325 Acked-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_tables.h | 6 ++---- net/netfilter/nf_tables_api.c | 17 +++++++++++------ 2 files changed, 13 insertions(+), 10 deletions(-) diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index c331e96a713b..ed0687b0e0f4 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -416,7 +416,8 @@ struct nft_set { unsigned char *udata; /* runtime data below here */ const struct nft_set_ops *ops ____cacheline_aligned; - u16 flags:14, + u16 flags:13, + bound:1, genmask:2; u8 klen; u8 dlen; @@ -1344,15 +1345,12 @@ struct nft_trans_rule { struct nft_trans_set { struct nft_set *set; u32 set_id; - bool bound; }; #define nft_trans_set(trans) \ (((struct nft_trans_set *)trans->data)->set) #define nft_trans_set_id(trans) \ (((struct nft_trans_set *)trans->data)->set_id) -#define nft_trans_set_bound(trans) \ - (((struct nft_trans_set *)trans->data)->bound) struct nft_trans_chain { bool update; diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index faf6bd10a19f..1333bf97dc26 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -142,7 +142,7 @@ static void nft_set_trans_bind(const struct nft_ctx *ctx, struct nft_set *set) list_for_each_entry_reverse(trans, &net->nft.commit_list, list) { if (trans->msg_type == NFT_MSG_NEWSET && nft_trans_set(trans) == set) { - nft_trans_set_bound(trans) = true; + set->bound = true; break; } } @@ -6709,8 +6709,7 @@ static void nf_tables_abort_release(struct nft_trans *trans) nf_tables_rule_destroy(&trans->ctx, nft_trans_rule(trans)); break; case NFT_MSG_NEWSET: - if (!nft_trans_set_bound(trans)) - nft_set_destroy(nft_trans_set(trans)); + nft_set_destroy(nft_trans_set(trans)); break; case NFT_MSG_NEWSETELEM: nft_set_elem_destroy(nft_trans_elem_set(trans), @@ -6783,8 +6782,11 @@ static int __nf_tables_abort(struct net *net) break; case NFT_MSG_NEWSET: trans->ctx.table->use--; - if (!nft_trans_set_bound(trans)) - list_del_rcu(&nft_trans_set(trans)->list); + if (nft_trans_set(trans)->bound) { + nft_trans_destroy(trans); + break; + } + list_del_rcu(&nft_trans_set(trans)->list); break; case NFT_MSG_DELSET: trans->ctx.table->use++; @@ -6792,8 +6794,11 @@ static int __nf_tables_abort(struct net *net) nft_trans_destroy(trans); break; case NFT_MSG_NEWSETELEM: + if (nft_trans_elem_set(trans)->bound) { + nft_trans_destroy(trans); + break; + } te = (struct nft_trans_elem *)trans->data; - te->set->ops->remove(net, te->set, &te->elem); atomic_dec(&te->set->nelems); break; -- 2.11.0