From patchwork Fri Mar 12 15:04:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Antoine Tenart X-Patchwork-Id: 12134875 X-Patchwork-Delegate: kuba@kernel.org 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=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 89D84C43332 for ; Fri, 12 Mar 2021 15:06:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 74EA364FD6 for ; Fri, 12 Mar 2021 15:06:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232262AbhCLPFs (ORCPT ); Fri, 12 Mar 2021 10:05:48 -0500 Received: from mail.kernel.org ([198.145.29.99]:43828 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232119AbhCLPFX (ORCPT ); Fri, 12 Mar 2021 10:05:23 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id EDD2F64F80; Fri, 12 Mar 2021 15:05:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615561523; bh=OtJELyvwxwbcqivCTKnOesWBm51y5qBsGR0qwAtSA/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r/zvwTXlLVqfIa8sQNbIBjRKKH3+9r7E0q3KEoDT+L9PBNaqfyNhqydDtdqwZXNxC 0xzwFiXt62tOptdVzNBjAlsthEqf/tYzq7pn8u8jQmd2Q+51QD+vSjzsjtgJHjhCq/ 2woB6fZ78uzfIzp2vrq9wvF+9RYlnEvQE1JcYqZaJN1GNi2cDJfVUtEDNanaLflk3c ylKKuKGngaDwU3zyVpaNzVXSlmhcRveMTuQ/7jlr8Vs0eyp9FeWs7oqZQDLrjB8ofZ 1y2CFCnmPuCAj3IHHfb8mCOl/qyAZhD2Nk2quKdYz54AhqvcO3obE92swbOIjAW5J/ rGtYUThlK4Xuw== From: Antoine Tenart To: davem@davemloft.net, kuba@kernel.org, alexander.duyck@gmail.com Cc: Antoine Tenart , netdev@vger.kernel.org Subject: [PATCH net-next v3 13/16] net: fix use after free in xps Date: Fri, 12 Mar 2021 16:04:41 +0100 Message-Id: <20210312150444.355207-14-atenart@kernel.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210312150444.355207-1-atenart@kernel.org> References: <20210312150444.355207-1-atenart@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org When setting up an new dev_maps in __netif_set_xps_queue, we remove and free maps from unused CPUs/rx-queues near the end of the function; by calling remove_xps_queue. However it's possible those maps are also part of the old not-freed-yet dev_maps, which might be used concurrently. When that happens, a map can be freed while its corresponding entry in the old dev_maps table isn't NULLed, leading to: BUG: KASAN: use-after-free in xps_queue_show+0x469/0x480 This fixes the map freeing logic for unused CPUs/rx-queues, to also NULL the map entries from the old dev_maps table. Signed-off-by: Antoine Tenart --- net/core/dev.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 052797ca65f6..748e377c7fe3 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2460,7 +2460,7 @@ static DEFINE_MUTEX(xps_map_mutex); rcu_dereference_protected((P), lockdep_is_held(&xps_map_mutex)) static bool remove_xps_queue(struct xps_dev_maps *dev_maps, - int tci, u16 index) + struct xps_dev_maps *old_maps, int tci, u16 index) { struct xps_map *map = NULL; int pos; @@ -2479,6 +2479,8 @@ static bool remove_xps_queue(struct xps_dev_maps *dev_maps, break; } + if (old_maps) + RCU_INIT_POINTER(old_maps->attr_map[tci], NULL); RCU_INIT_POINTER(dev_maps->attr_map[tci], NULL); kfree_rcu(map, rcu); return false; @@ -2499,7 +2501,7 @@ static bool remove_xps_queue_cpu(struct net_device *dev, int i, j; for (i = count, j = offset; i--; j++) { - if (!remove_xps_queue(dev_maps, tci, j)) + if (!remove_xps_queue(dev_maps, NULL, tci, j)) break; } @@ -2631,7 +2633,7 @@ static void xps_copy_dev_maps(struct xps_dev_maps *dev_maps, int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask, u16 index, enum xps_map_type type) { - struct xps_dev_maps *dev_maps, *new_dev_maps = NULL; + struct xps_dev_maps *dev_maps, *new_dev_maps = NULL, *old_dev_maps = NULL; const unsigned long *online_mask = NULL; bool active = false, copy = false; int i, j, tci, numa_node_id = -2; @@ -2768,7 +2770,7 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask, } } - kfree_rcu(dev_maps, rcu); + old_dev_maps = copy ? dev_maps : NULL; out_no_old_maps: dev_maps = new_dev_maps; @@ -2794,10 +2796,14 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask, netif_attr_test_online(j, online_mask, dev_maps->nr_ids)) continue; - active |= remove_xps_queue(dev_maps, tci, index); + active |= remove_xps_queue(dev_maps, old_dev_maps, tci, + index); } } + if (old_dev_maps) + kfree_rcu(old_dev_maps, rcu); + /* free map if not active */ if (!active) reset_xps_maps(dev, dev_maps, type);