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,URIBL_BLOCKED, 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 1DBB2C282CD for ; Mon, 28 Jan 2019 14:04:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EE54721738 for ; Mon, 28 Jan 2019 14:04:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726951AbfA1OER (ORCPT ); Mon, 28 Jan 2019 09:04:17 -0500 Received: from mail.us.es ([193.147.175.20]:35412 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726864AbfA1OEQ (ORCPT ); Mon, 28 Jan 2019 09:04:16 -0500 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 1E3E92D9AE3 for ; Mon, 28 Jan 2019 15:04:14 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 05F83DA87C for ; Mon, 28 Jan 2019 15:04:14 +0100 (CET) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 04E65DA87B; Mon, 28 Jan 2019 15:04:14 +0100 (CET) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id D6A8ADA84C; Mon, 28 Jan 2019 15:04:11 +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, 28 Jan 2019 15:04:11 +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 A9AFE4265A2F; Mon, 28 Jan 2019 15:04:11 +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 3/7] netfilter: nft_compat: destroy function must not have side effects Date: Mon, 28 Jan 2019 15:04:01 +0100 Message-Id: <20190128140405.15020-4-pablo@netfilter.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190128140405.15020-1-pablo@netfilter.org> References: <20190128140405.15020-1-pablo@netfilter.org> X-Virus-Scanned: ClamAV using ClamSMTP Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Florian Westphal The nft_compat destroy function deletes the nft_xt object from a list. This isn't allowed anymore. Destroy functions are called asynchronously, i.e. next batch can find the object that has a pending ->destroy() invocation: cpu0 cpu1 worker ->destroy for_each_entry() if (x == ... return x->ops; list_del(x) kfree_rcu(x) expr->ops->... // ops was free'd To resolve this, the list_del needs to occur before the transaction mutex gets released. nf_tables has a 'deactivate' hook for this purpose, so use that to unlink the object from the list. Fixes: 0935d5588400 ("netfilter: nf_tables: asynchronous release") Reported-by: Taehee Yoo Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nft_compat.c | 48 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 47 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c index abed3490a8f8..5eb269428832 100644 --- a/net/netfilter/nft_compat.c +++ b/net/netfilter/nft_compat.c @@ -29,6 +29,9 @@ struct nft_xt { struct nft_expr_ops ops; refcount_t refcnt; + /* used only when transaction mutex is locked */ + unsigned int listcnt; + /* Unlike other expressions, ops doesn't have static storage duration. * nft core assumes they do. We use kfree_rcu so that nft core can * can check expr->ops->size even after nft_compat->destroy() frees @@ -61,7 +64,7 @@ static struct nft_compat_net *nft_compat_pernet(struct net *net) static bool nft_xt_put(struct nft_xt *xt) { if (refcount_dec_and_test(&xt->refcnt)) { - list_del(&xt->head); + WARN_ON_ONCE(!list_empty(&xt->head)); kfree_rcu(xt, rcu_head); return true; } @@ -555,6 +558,43 @@ nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr) __nft_match_destroy(ctx, expr, nft_expr_priv(expr)); } +static void nft_compat_activate(const struct nft_ctx *ctx, + const struct nft_expr *expr, + struct list_head *h) +{ + struct nft_xt *xt = container_of(expr->ops, struct nft_xt, ops); + + if (xt->listcnt == 0) + list_add(&xt->head, h); + + xt->listcnt++; +} + +static void nft_compat_activate_mt(const struct nft_ctx *ctx, + const struct nft_expr *expr) +{ + struct nft_compat_net *cn = nft_compat_pernet(ctx->net); + + nft_compat_activate(ctx, expr, &cn->nft_match_list); +} + +static void nft_compat_activate_tg(const struct nft_ctx *ctx, + const struct nft_expr *expr) +{ + struct nft_compat_net *cn = nft_compat_pernet(ctx->net); + + nft_compat_activate(ctx, expr, &cn->nft_target_list); +} + +static void nft_compat_deactivate(const struct nft_ctx *ctx, + const struct nft_expr *expr) +{ + struct nft_xt *xt = container_of(expr->ops, struct nft_xt, ops); + + if (--xt->listcnt == 0) + list_del_init(&xt->head); +} + static void nft_match_large_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr) { @@ -808,6 +848,8 @@ nft_match_select_ops(const struct nft_ctx *ctx, nft_match->ops.eval = nft_match_eval; nft_match->ops.init = nft_match_init; nft_match->ops.destroy = nft_match_destroy; + nft_match->ops.activate = nft_compat_activate_mt; + nft_match->ops.deactivate = nft_compat_deactivate; nft_match->ops.dump = nft_match_dump; nft_match->ops.validate = nft_match_validate; nft_match->ops.data = match; @@ -824,6 +866,7 @@ nft_match_select_ops(const struct nft_ctx *ctx, nft_match->ops.size = matchsize; + nft_match->listcnt = 1; list_add(&nft_match->head, &cn->nft_match_list); return &nft_match->ops; @@ -910,6 +953,8 @@ nft_target_select_ops(const struct nft_ctx *ctx, nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize)); nft_target->ops.init = nft_target_init; nft_target->ops.destroy = nft_target_destroy; + nft_target->ops.activate = nft_compat_activate_tg; + nft_target->ops.deactivate = nft_compat_deactivate; nft_target->ops.dump = nft_target_dump; nft_target->ops.validate = nft_target_validate; nft_target->ops.data = target; @@ -919,6 +964,7 @@ nft_target_select_ops(const struct nft_ctx *ctx, else nft_target->ops.eval = nft_target_eval_xt; + nft_target->listcnt = 1; list_add(&nft_target->head, &cn->nft_target_list); return &nft_target->ops; -- 2.11.0