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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 64B4DC433E0 for ; Tue, 9 Jun 2020 18:05:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3BDD7206D5 for ; Tue, 9 Jun 2020 18:05:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591725900; bh=2wq8q15ub0uB0vMe8hgGxS46CrFW/myQrAZmv2wOkoE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rtWHKruhj00LUMmZgTMA0JsIn4SgRKVutCIuN4YyIrTrd8q5dwDydLNmPtGGipeIM AX+Kwfzb/1pf1PL6BJCbFcuxt3XySStYu5ux5g1EPTqL8jOH4tF6/1mDwWuvJukzqz Yu7T0ybQRcfsbY9+y4x9/gQY7VAnUCNaEQImI0xQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730901AbgFIRvx (ORCPT ); Tue, 9 Jun 2020 13:51:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:41448 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732877AbgFIRvt (ORCPT ); Tue, 9 Jun 2020 13:51:49 -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 BE0D1207ED; Tue, 9 Jun 2020 17:51:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591725109; bh=2wq8q15ub0uB0vMe8hgGxS46CrFW/myQrAZmv2wOkoE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wrfOIVqGUldUVb82vmo5as5T1A8ITA9rNNm+1coUb+MQtyrnfzHaIwU39gDmHil/M zK/5K45JlfsZJhpgzCJdwKuoWqPZbGyJNbnDurTenMczM6eI1XT0ktBESC198GXK7U S8+iil764pKLjAvkLUqrnPNvLVvgkpT7Js7zxHNM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot , Willem de Bruijn , "David S. Miller" Subject: [PATCH 4.19 07/25] net: check untrusted gso_size at kernel entry Date: Tue, 9 Jun 2020 19:44:57 +0200 Message-Id: <20200609174049.478235209@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200609174048.576094775@linuxfoundation.org> References: <20200609174048.576094775@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 From: Willem de Bruijn [ Upstream commit 6dd912f82680761d8fb6b1bb274a69d4c7010988 ] Syzkaller again found a path to a kernel crash through bad gso input: a packet with gso size exceeding len. These packets are dropped in tcp_gso_segment and udp[46]_ufo_fragment. But they may affect gso size calculations earlier in the path. Now that we have thlen as of commit 9274124f023b ("net: stricter validation of untrusted gso packets"), check gso_size at entry too. Fixes: bfd5f4a3d605 ("packet: Add GSO/csum offload support.") Reported-by: syzbot Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/virtio_net.h | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -31,6 +31,7 @@ static inline int virtio_net_hdr_to_skb( { unsigned int gso_type = 0; unsigned int thlen = 0; + unsigned int p_off = 0; unsigned int ip_proto; if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { @@ -68,7 +69,8 @@ static inline int virtio_net_hdr_to_skb( if (!skb_partial_csum_set(skb, start, off)) return -EINVAL; - if (skb_transport_offset(skb) + thlen > skb_headlen(skb)) + p_off = skb_transport_offset(skb) + thlen; + if (p_off > skb_headlen(skb)) return -EINVAL; } else { /* gso packets without NEEDS_CSUM do not set transport_offset. @@ -92,17 +94,25 @@ retry: return -EINVAL; } - if (keys.control.thoff + thlen > skb_headlen(skb) || + p_off = keys.control.thoff + thlen; + if (p_off > skb_headlen(skb) || keys.basic.ip_proto != ip_proto) return -EINVAL; skb_set_transport_header(skb, keys.control.thoff); + } else if (gso_type) { + p_off = thlen; + if (p_off > skb_headlen(skb)) + return -EINVAL; } } if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { u16 gso_size = __virtio16_to_cpu(little_endian, hdr->gso_size); + if (skb->len - p_off <= gso_size) + return -EINVAL; + skb_shinfo(skb)->gso_size = gso_size; skb_shinfo(skb)->gso_type = gso_type;