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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2780FC678D4 for ; Mon, 16 Jan 2023 17:11:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232398AbjAPRLJ (ORCPT ); Mon, 16 Jan 2023 12:11:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234318AbjAPRKq (ORCPT ); Mon, 16 Jan 2023 12:10:46 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FA0930B2E for ; Mon, 16 Jan 2023 08:50:50 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id DD38BB8109D for ; Mon, 16 Jan 2023 16:50:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 42688C433EF; Mon, 16 Jan 2023 16:50:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673887847; bh=XsbQtOaZ3eU/1ChvimzePTn6jNqCJ9TZVPXd9HThSo4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M0jlOULukG5CSxMiaiUiEqEwgZ2PByf6C/4ncWMyXSbQhGhydUXiuVl7H8j8aoNSv mrklIwbT+h1EdWetfvBWVUHya55ThZ4ZCpIIenkzBohFEZFeTsUhou+4Q1D67XXbRz hn2e3yEO9MNOCR4yYBJWGy9KlzEDGH9cBZfFSueU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sean Tranchetti , Subash Abhinov Kasiviswanathan , Alexander Duyck , Jakub Kicinski , Sasha Levin Subject: [PATCH 4.19 305/521] skbuff: Account for tail adjustment during pull operations Date: Mon, 16 Jan 2023 16:49:27 +0100 Message-Id: <20230116154900.769087213@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154847.246743274@linuxfoundation.org> References: <20230116154847.246743274@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Subash Abhinov Kasiviswanathan [ Upstream commit 2d7afdcbc9d32423f177ee12b7c93783aea338fb ] Extending the tail can have some unexpected side effects if a program uses a helper like BPF_FUNC_skb_pull_data to read partial content beyond the head skb headlen when all the skbs in the gso frag_list are linear with no head_frag - kernel BUG at net/core/skbuff.c:4219! pc : skb_segment+0xcf4/0xd2c lr : skb_segment+0x63c/0xd2c Call trace: skb_segment+0xcf4/0xd2c __udp_gso_segment+0xa4/0x544 udp4_ufo_fragment+0x184/0x1c0 inet_gso_segment+0x16c/0x3a4 skb_mac_gso_segment+0xd4/0x1b0 __skb_gso_segment+0xcc/0x12c udp_rcv_segment+0x54/0x16c udp_queue_rcv_skb+0x78/0x144 udp_unicast_rcv_skb+0x8c/0xa4 __udp4_lib_rcv+0x490/0x68c udp_rcv+0x20/0x30 ip_protocol_deliver_rcu+0x1b0/0x33c ip_local_deliver+0xd8/0x1f0 ip_rcv+0x98/0x1a4 deliver_ptype_list_skb+0x98/0x1ec __netif_receive_skb_core+0x978/0xc60 Fix this by marking these skbs as GSO_DODGY so segmentation can handle the tail updates accordingly. Fixes: 3dcbdb134f32 ("net: gso: Fix skb_segment splat when splitting gso_size mangled skb having linear-headed frag_list") Signed-off-by: Sean Tranchetti Signed-off-by: Subash Abhinov Kasiviswanathan Reviewed-by: Alexander Duyck Link: https://lore.kernel.org/r/1671084718-24796-1-git-send-email-quic_subashab@quicinc.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/skbuff.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 4178fc28c277..7f501dff4501 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1953,6 +1953,9 @@ void *__pskb_pull_tail(struct sk_buff *skb, int delta) insp = list; } else { /* Eaten partially. */ + if (skb_is_gso(skb) && !list->head_frag && + skb_headlen(list)) + skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; if (skb_shared(list)) { /* Sucks! We need to fork list. :-( */ -- 2.35.1