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=-9.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 5FE83C43381 for ; Sat, 23 Feb 2019 21:28:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2BB3520652 for ; Sat, 23 Feb 2019 21:28:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550957307; bh=VcsB3pNZSpFzMTjD0LZmczWhbZh44ujquiyNeBgpxV4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=NMC72rtbtOVbxcJtPIYLMu7duaRSVtgM/bZ1OxtMZS9ih5ae0CbAPuyJnU/qKpw0F 1LgJR9vNm/YY8VNMwNtTPgKnSG/xwpt7NZtPeYO2nMl6A8veLyFiyyloBTWwd6NSIm 1ehfTRJpjWMOmhSZ/J86woEc4i6P6xuMf9ZgUel0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728528AbfBWV2Z (ORCPT ); Sat, 23 Feb 2019 16:28:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:41896 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728816AbfBWVGq (ORCPT ); Sat, 23 Feb 2019 16:06:46 -0500 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 B9E692086A; Sat, 23 Feb 2019 21:06:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550956005; bh=VcsB3pNZSpFzMTjD0LZmczWhbZh44ujquiyNeBgpxV4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UQ7KatCl0OPy1jiKJKO2DCgPVn59hhahEnbgihbstlrPfXF3xXr+dPfJboMk2plRI qe9k1rt6laAGZTgQ/WI9fkjBotDiQ9ScuJ7jpiAOp6nM36OV3QFG7FZgpytco4QBp/ 936NSdg9U5UaIuvPtUWvo4PNB2/I1Jkue5Rsuw3U= 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 4.19 04/65] netfilter: nft_compat: use refcnt_t type for nft_xt reference count Date: Sat, 23 Feb 2019 16:05:39 -0500 Message-Id: <20190223210640.200911-4-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190223210640.200911-1-sashal@kernel.org> References: <20190223210640.200911-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Florian Westphal [ Upstream commit 12c44aba6618b7f6c437076e5722237190f6cd5f ] Using standard integer type was fine while all operations on it were guarded by the nftnl subsys mutex. This isn't true anymore: 1. transactions are guarded only by a pernet mutex, so concurrent rule manipulation in different netns is racy 2. the ->destroy hook runs from a work queue after the transaction mutex has been released already. cpu0 cpu1 (net 1) cpu2 (net 2) kworker nft_compat->destroy nft_compat->init nft_compat->init if (--nft_xt->ref == 0) nft_xt->ref++ nft_xt->ref++ Switch to refcount_t. Doing this however only fixes a minor aspect, nft_compat also performs linked-list operations in an unsafe way. This is addressed in the next two patches. Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions") Fixes: 0935d5588400 ("netfilter: nf_tables: asynchronous release") Reported-by: Taehee Yoo Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nft_compat.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c index 29d6fc73caf99..3e629ee59ddab 100644 --- a/net/netfilter/nft_compat.c +++ b/net/netfilter/nft_compat.c @@ -26,7 +26,7 @@ struct nft_xt { struct list_head head; struct nft_expr_ops ops; - unsigned int refcnt; + refcount_t refcnt; /* Unlike other expressions, ops doesn't have static storage duration. * nft core assumes they do. We use kfree_rcu so that nft core can @@ -45,7 +45,7 @@ struct nft_xt_match_priv { static bool nft_xt_put(struct nft_xt *xt) { - if (--xt->refcnt == 0) { + if (refcount_dec_and_test(&xt->refcnt)) { list_del(&xt->head); kfree_rcu(xt, rcu_head); return true; @@ -273,7 +273,7 @@ nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr, return -EINVAL; nft_xt = container_of(expr->ops, struct nft_xt, ops); - nft_xt->refcnt++; + refcount_inc(&nft_xt->refcnt); return 0; } @@ -467,7 +467,7 @@ __nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr, return ret; nft_xt = container_of(expr->ops, struct nft_xt, ops); - nft_xt->refcnt++; + refcount_inc(&nft_xt->refcnt); return 0; } @@ -769,7 +769,7 @@ nft_match_select_ops(const struct nft_ctx *ctx, goto err; } - nft_match->refcnt = 0; + refcount_set(&nft_match->refcnt, 0); nft_match->ops.type = &nft_match_type; nft_match->ops.eval = nft_match_eval; nft_match->ops.init = nft_match_init; @@ -873,7 +873,7 @@ nft_target_select_ops(const struct nft_ctx *ctx, goto err; } - nft_target->refcnt = 0; + refcount_set(&nft_target->refcnt, 0); nft_target->ops.type = &nft_target_type; nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize)); nft_target->ops.init = nft_target_init; @@ -944,7 +944,7 @@ static void __exit nft_compat_module_exit(void) list_for_each_entry_safe(xt, next, &nft_target_list, head) { struct xt_target *target = xt->ops.data; - if (WARN_ON_ONCE(xt->refcnt)) + if (WARN_ON_ONCE(refcount_read(&xt->refcnt))) continue; module_put(target->me); kfree(xt); @@ -953,7 +953,7 @@ static void __exit nft_compat_module_exit(void) list_for_each_entry_safe(xt, next, &nft_match_list, head) { struct xt_match *match = xt->ops.data; - if (WARN_ON_ONCE(xt->refcnt)) + if (WARN_ON_ONCE(refcount_read(&xt->refcnt))) continue; module_put(match->me); kfree(xt); -- 2.19.1