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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 77A83C43219 for ; Tue, 30 Apr 2019 11:43:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4804F21707 for ; Tue, 30 Apr 2019 11:43:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556624633; bh=mcG4bxiT62agVN+/5uDUUQh3M/OB3bDp0haUKaJTbjk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=1Ns8TCAeQ3emVwwoNu9rU9xqoX9q4KUDsYEopYvVJKX0t/UUhbYRAXTVEGpZGC/5/ bHlUYzc6B/AS1cQu7PF+P85yLDxhotWwVLyPErkwTggnDOhWYQHYdv6KZ857TOXtm/ R56gZtX8m+kR8KArxRqDfsv5IHeGgGUFZ7/JZsYQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730025AbfD3Lnw (ORCPT ); Tue, 30 Apr 2019 07:43:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:54394 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730008AbfD3Lns (ORCPT ); Tue, 30 Apr 2019 07:43:48 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2206C20449; Tue, 30 Apr 2019 11:43:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556624627; bh=mcG4bxiT62agVN+/5uDUUQh3M/OB3bDp0haUKaJTbjk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uEuzhr4mKYSuwbsHkXwM6/vhnC2J8Qbzu+Q/s3Z1n2IXQazmRwdWWZjl4BvJBvY0q o11K8t31JztPAL7cdgg3KfO825ZlLSrFPnr6n+klzNjzL6P05BHpYF+oYQpl8nhx4L 5SkMQgSwsYWZ+cLry1c8KBfsptzmP0r8dikox+EA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Taehee Yoo , Florian Westphal , Pablo Neira Ayuso Subject: [PATCH 4.19 004/100] netfilter: nft_compat: destroy function must not have side effects Date: Tue, 30 Apr 2019 13:37:33 +0200 Message-Id: <20190430113608.853693719@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190430113608.616903219@linuxfoundation.org> References: <20190430113608.616903219@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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 61c098555507..432139b7fa1f 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; } @@ -537,6 +540,43 @@ 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) { @@ -789,6 +829,8 @@ 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; @@ -805,6 +847,7 @@ 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; @@ -891,6 +934,8 @@ 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; @@ -900,6 +945,7 @@ 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; -- 2.19.1