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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 2C7BEC433E0 for ; Tue, 9 Jun 2020 00:08:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B2762074B for ; Tue, 9 Jun 2020 00:08:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591661316; bh=/vbQSAarfWCrkIH4Xhngwau6L7c14Hu+WRKH7eUcJhk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XH1eBo6bzLiKzRu6dXxugeiEh8RhNS/mKa/EayqyOlO6YCB1h7U2wPOmNyx/6+G0I b7JS6WNa6wGfXZwA+DnRAaOV6NFSbypEXnWgfdq/63Z8Q+/BN3sTKQOYtEI8x/FUmb 1U1wKafRfUDZF5HLKoScvlOeGow/vDM/yQJ5sHEs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731000AbgFHXUi (ORCPT ); Mon, 8 Jun 2020 19:20:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:37930 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729739AbgFHXQd (ORCPT ); Mon, 8 Jun 2020 19:16:33 -0400 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 ABE2E20820; Mon, 8 Jun 2020 23:16:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658193; bh=/vbQSAarfWCrkIH4Xhngwau6L7c14Hu+WRKH7eUcJhk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m2XAC9UN/tst8CXkIeUs4LN2tNdu0qKHCFL7gwvNNTZ69rycM1v6+8dpyZK/VhehV BAli82BrtAle8Pn83vKWnVgWe3HXCg6STYROU+QHDJnYGMboaZVb+XZILM0lk7O7aK 7RXbbbj07B0Re5YcDfTSF15Z9FfJPKqs739GzQn8= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Boris Sukholitko , Edward Cree , "David S . Miller" , Greg Kroah-Hartman , netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.6 214/606] __netif_receive_skb_core: pass skb by reference Date: Mon, 8 Jun 2020 19:05:39 -0400 Message-Id: <20200608231211.3363633-214-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231211.3363633-1-sashal@kernel.org> References: <20200608231211.3363633-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review 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: Boris Sukholitko [ Upstream commit c0bbbdc32febd4f034ecbf3ea17865785b2c0652 ] __netif_receive_skb_core may change the skb pointer passed into it (e.g. in rx_handler). The original skb may be freed as a result of this operation. The callers of __netif_receive_skb_core may further process original skb by using pt_prev pointer returned by __netif_receive_skb_core thus leading to unpleasant effects. The solution is to pass skb by reference into __netif_receive_skb_core. v2: Added Fixes tag and comment regarding ppt_prev and skb invariant. Fixes: 88eb1944e18c ("net: core: propagate SKB lists through packet_type lookup") Signed-off-by: Boris Sukholitko Acked-by: Edward Cree Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/dev.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index c7047b40f569..87fd5424e205 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4988,11 +4988,12 @@ static inline int nf_ingress(struct sk_buff *skb, struct packet_type **pt_prev, return 0; } -static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc, +static int __netif_receive_skb_core(struct sk_buff **pskb, bool pfmemalloc, struct packet_type **ppt_prev) { struct packet_type *ptype, *pt_prev; rx_handler_func_t *rx_handler; + struct sk_buff *skb = *pskb; struct net_device *orig_dev; bool deliver_exact = false; int ret = NET_RX_DROP; @@ -5023,8 +5024,10 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc, ret2 = do_xdp_generic(rcu_dereference(skb->dev->xdp_prog), skb); preempt_enable(); - if (ret2 != XDP_PASS) - return NET_RX_DROP; + if (ret2 != XDP_PASS) { + ret = NET_RX_DROP; + goto out; + } skb_reset_mac_len(skb); } @@ -5174,6 +5177,13 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc, } out: + /* The invariant here is that if *ppt_prev is not NULL + * then skb should also be non-NULL. + * + * Apparently *ppt_prev assignment above holds this invariant due to + * skb dereferencing near it. + */ + *pskb = skb; return ret; } @@ -5183,7 +5193,7 @@ static int __netif_receive_skb_one_core(struct sk_buff *skb, bool pfmemalloc) struct packet_type *pt_prev = NULL; int ret; - ret = __netif_receive_skb_core(skb, pfmemalloc, &pt_prev); + ret = __netif_receive_skb_core(&skb, pfmemalloc, &pt_prev); if (pt_prev) ret = INDIRECT_CALL_INET(pt_prev->func, ipv6_rcv, ip_rcv, skb, skb->dev, pt_prev, orig_dev); @@ -5261,7 +5271,7 @@ static void __netif_receive_skb_list_core(struct list_head *head, bool pfmemallo struct packet_type *pt_prev = NULL; skb_list_del_init(skb); - __netif_receive_skb_core(skb, pfmemalloc, &pt_prev); + __netif_receive_skb_core(&skb, pfmemalloc, &pt_prev); if (!pt_prev) continue; if (pt_curr != pt_prev || od_curr != orig_dev) { -- 2.25.1