From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1886372-1527163006-2-16226788867381012392 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, MAILING_LIST_MULTI -1, RCVD_IN_DNSWL_HI -5, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1527163005; b=YR7PeifjYsAAILytOmEmpGw8m0tsQzbP3tqjPwk17inW6jU6P8 CikRdD7twxOENZp3zPvuu/2Afwln78EiNrkoxsEc0tqsV/ki/QMmaXgX8sScVAAC ZYYl4dhwe+xvqu6tJHilzVeXu3j8pJMlKSdBTMFhLpYW9d5BAhGhHOMhqJ4oreUm 5okGUcqMjH/eYa1YiHKbrTPsdLbkS3HN9ibRWMz7RKz7cXr8HFigReZh36sR+53D lKZKEW+XduGzwkhzA43YrP6KtPvKvSyvNXMriNpHCbwKtUskSu4h2k33mckdWVzL 3/EXPAu4++UpHkcAYPENZQATZnCUGjFyISWQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=fm2; t=1527163005; bh=JLU9O5UeOsa+0ncVhx+j7sWgOxNAxE MqOS8c8kxPUjo=; b=iMsgDXryi/H3aCSHuRkz7COkRbzYpvByRpfJEg/KGSZIEo JeqaI7XINGb4BzQV8RTJxpfEtkCQOAuQxfJvc+iXLWZigV3jfcAol/6T8hYzAG24 qXWkS8JheL34hWfVOg9y+YtKxyxPmgMTEfU8g32jIJNF5iBAorFvY0bJ90h7fFJU 4R/Y5GY2htd23VQsLgCfV7OvJYWKyms/Xlwb7uyUADuRW8pwR9wjyqNfdUz/SDXp 6/zA4AUq/mWmL91xc2gBgIA8245ObgBuoVXbZTkT2S+ZjxH2ijNiGDaWV404AoHE F37+wt/I7FhQEcnYerNOStiatj5luMkNirXx7GdA== ARC-Authentication-Results: i=1; mx1.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=MHCq8+ry x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx1.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=kernel.org header.i=@kernel.org header.b=MHCq8+ry x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=default; dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfPAKxecnG132CfgMokg6WIAFcOyHVHAzNbhpcBV5wJZYSdpZ/vanHnV7qter1KfWtiJsgxl9fFL4EQ+Eshdyp5zhuEdFZ7Ft+CiaLifPoH8Vq5clJm9S xdrN8EmEZ1vGt4y8nNm8HnBLAp5DKgyRKswOe0d1V4Knb4Ctp3svSx2YJZrbgZ6bF9JJx1u/8jgLWvzbpl4k3AHJkmcaPfx+h9BKOhj4+TjfI7Sc5uAwJ2Pd X-CM-Analysis: v=2.3 cv=WaUilXpX c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=VUJBJC2UJ8kA:10 a=1XWaLZrsAAAA:8 a=hSkVLCK3AAAA:8 a=J1Y8HTJGAAAA:8 a=ag1SF4gXAAAA:8 a=G8Vht56IOoz3jrsCRGQA:9 a=7CZQgDGIAkha4vUH:21 a=ise_7HGtSiYG6tJr:21 a=QEXdDO2ut3YA:10 a=cQPPKAXgyycSBL8etih5:22 a=y1Q9-5lHfBjTkpIzbSAN:22 a=Yupwre4RP9_Eg_Bd0iYG:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966438AbeEXL4R (ORCPT ); Thu, 24 May 2018 07:56:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:57020 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966843AbeEXJpv (ORCPT ); Thu, 24 May 2018 05:45:51 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+71d74a5406d02057d559@syzkaller.appspotmail.com, Willem de Bruijn , "David S. Miller" Subject: [PATCH 4.4 72/92] packet: in packet_snd start writing at link layer allocation Date: Thu, 24 May 2018 11:38:49 +0200 Message-Id: <20180524093206.227673739@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180524093159.286472249@linuxfoundation.org> References: <20180524093159.286472249@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Willem de Bruijn [ Upstream commit b84bbaf7a6c8cca24f8acf25a2c8e46913a947ba ] Packet sockets allow construction of packets shorter than dev->hard_header_len to accommodate protocols with variable length link layer headers. These packets are padded to dev->hard_header_len, because some device drivers interpret that as a minimum packet size. packet_snd reserves dev->hard_header_len bytes on allocation. SOCK_DGRAM sockets call skb_push in dev_hard_header() to ensure that link layer headers are stored in the reserved range. SOCK_RAW sockets do the same in tpacket_snd, but not in packet_snd. Syzbot was able to send a zero byte packet to a device with massive 116B link layer header, causing padding to cross over into skb_shinfo. Fix this by writing from the start of the llheader reserved range also in the case of packet_snd/SOCK_RAW. Update skb_set_network_header to the new offset. This also corrects it for SOCK_DGRAM, where it incorrectly double counted reserve due to the skb_push in dev_hard_header. Fixes: 9ed988cd5915 ("packet: validate variable length ll headers") Reported-by: syzbot+71d74a5406d02057d559@syzkaller.appspotmail.com Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/packet/af_packet.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2771,13 +2771,15 @@ static int packet_snd(struct socket *soc if (skb == NULL) goto out_unlock; - skb_set_network_header(skb, reserve); + skb_reset_network_header(skb); err = -EINVAL; if (sock->type == SOCK_DGRAM) { offset = dev_hard_header(skb, dev, ntohs(proto), addr, NULL, len); if (unlikely(offset < 0)) goto out_free; + } else if (reserve) { + skb_push(skb, reserve); } /* Returns -EFAULT on error */