From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-560692-1519835832-2-10078141081102945385 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 0.249, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='uk', 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=arctest; t=1519835832; b=ZLU0d8Zk4Y/v+mW/2O0OYUL599kKoNasR79++hJn9DLjULE 9mkeL77PHqyAdJNjwj3EZmlFITioJcJFqeqj2tBH7dCF4HAC1LgVcVMukGJ+nF+/ f9PTJtgAQGWz+z5IP5Z5aoDjMdR8Q4tXOTuXi8wQFDiKvnhLOdJr/M/jTT+IEPhf XtGxlTDVLsFL/8DAp4XTP85PlmPaztq7yd+wGiveUow35RYZVW0I1LmL34LeL5fP IdKpt6XsFHMvPnh9ApsBbS0tDxfKbqJ+GKEAR8eoNg/EMabOAopd/ADQrMy3ELBQ rwpVh/Nyaq8zOBOoxltLbyvsash8U+Pmy6epuqg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1519835832; bh=mNAuFt2kZNd0feB3WWG 38AcKYatdAtomUHIOCW2EJl0=; b=ma0Y5717B9VHEEUPEOslwT5sxM6LQ34hBj5 RKOwgYSRHuC320gnqFjId6v1/lIpCd3wmVn2UWMDhvthp8d7QXLf9tjOZhjM9EH4 G8G8A5x9izRydkhBbT8S96ek9D1/N+khc+DuO8stuo2S+51wAhv/CFKDS6z7BwAs dD0uH0PiBvV6/Rq8piw5yvU/Rl0bhaLC7lGGmVF74yqHeLBFY7sz8IO4zu3ZJR8c 7dYti9/x1bL7UPmlWm7Ih7/V1belLzAdkEJ04MHyMidOl+OYMNV/AWXRQrcbHBCr I0RHfjoUMPKbzNWJO9P4qLk+k6mYS6nDbBp1r7JLMix5u36fUIQ== ARC-Authentication-Results: i=1; mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; 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-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=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx1.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; 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-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=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932414AbeB1Qg6 (ORCPT ); Wed, 28 Feb 2018 11:36:58 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34841 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932839AbeB1QEo (ORCPT ); Wed, 28 Feb 2018 11:04:44 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Guillaume Nault" , "David S. Miller" , syzbot+ed0838d0fa4c4f2b528e20286e6dc63effc7c14d@syzkaller.appspotmail.com, "Xin Long" Date: Wed, 28 Feb 2018 15:20:18 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 227/254] pppoe: take ->needed_headroom of lower device into account on xmit In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false 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: 3.16.55-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Guillaume Nault commit 02612bb05e51df8489db5e94d0cf8d1c81f87b0c upstream. In pppoe_sendmsg(), reserving dev->hard_header_len bytes of headroom was probably fine before the introduction of ->needed_headroom in commit f5184d267c1a ("net: Allow netdevices to specify needed head/tailroom"). But now, virtual devices typically advertise the size of their overhead in dev->needed_headroom, so we must also take it into account in skb_reserve(). Allocation size of skb is also updated to take dev->needed_tailroom into account and replace the arbitrary 32 bytes with the real size of a PPPoE header. This issue was discovered by syzbot, who connected a pppoe socket to a gre device which had dev->header_ops->create == ipgre_header and dev->hard_header_len == 0. Therefore, PPPoE didn't reserve any headroom, and dev_hard_header() crashed when ipgre_header() tried to prepend its header to skb->data. skbuff: skb_under_panic: text:000000001d390b3a len:31 put:24 head:00000000d8ed776f data:000000008150e823 tail:0x7 end:0xc0 dev:gre0 ------------[ cut here ]------------ kernel BUG at net/core/skbuff.c:104! invalid opcode: 0000 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 3670 Comm: syzkaller801466 Not tainted 4.15.0-rc7-next-20180115+ #97 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:skb_panic+0x162/0x1f0 net/core/skbuff.c:100 RSP: 0018:ffff8801d9bd7840 EFLAGS: 00010282 RAX: 0000000000000083 RBX: ffff8801d4f083c0 RCX: 0000000000000000 RDX: 0000000000000083 RSI: 1ffff1003b37ae92 RDI: ffffed003b37aefc RBP: ffff8801d9bd78a8 R08: 1ffff1003b37ae8a R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff86200de0 R13: ffffffff84a981ad R14: 0000000000000018 R15: ffff8801d2d34180 FS: 00000000019c4880(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000208bc000 CR3: 00000001d9111001 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: skb_under_panic net/core/skbuff.c:114 [inline] skb_push+0xce/0xf0 net/core/skbuff.c:1714 ipgre_header+0x6d/0x4e0 net/ipv4/ip_gre.c:879 dev_hard_header include/linux/netdevice.h:2723 [inline] pppoe_sendmsg+0x58e/0x8b0 drivers/net/ppp/pppoe.c:890 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg+0xca/0x110 net/socket.c:640 sock_write_iter+0x31a/0x5d0 net/socket.c:909 call_write_iter include/linux/fs.h:1775 [inline] do_iter_readv_writev+0x525/0x7f0 fs/read_write.c:653 do_iter_write+0x154/0x540 fs/read_write.c:932 vfs_writev+0x18a/0x340 fs/read_write.c:977 do_writev+0xfc/0x2a0 fs/read_write.c:1012 SYSC_writev fs/read_write.c:1085 [inline] SyS_writev+0x27/0x30 fs/read_write.c:1082 entry_SYSCALL_64_fastpath+0x29/0xa0 Admittedly PPPoE shouldn't be allowed to run on non Ethernet-like interfaces, but reserving space for ->needed_headroom is a more fundamental issue that needs to be addressed first. Same problem exists for __pppoe_xmit(), which also needs to take dev->needed_headroom into account in skb_cow_head(). Fixes: f5184d267c1a ("net: Allow netdevices to specify needed head/tailroom") Reported-by: syzbot+ed0838d0fa4c4f2b528e20286e6dc63effc7c14d@syzkaller.appspotmail.com Signed-off-by: Guillaume Nault Reviewed-by: Xin Long Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- drivers/net/ppp/pppoe.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) --- a/drivers/net/ppp/pppoe.c +++ b/drivers/net/ppp/pppoe.c @@ -832,6 +832,7 @@ static int pppoe_sendmsg(struct kiocb *i struct pppoe_hdr *ph; struct net_device *dev; char *start; + int hlen; lock_sock(sk); if (sock_flag(sk, SOCK_DEAD) || !(sk->sk_state & PPPOX_CONNECTED)) { @@ -850,16 +851,16 @@ static int pppoe_sendmsg(struct kiocb *i if (total_len > (dev->mtu + dev->hard_header_len)) goto end; - - skb = sock_wmalloc(sk, total_len + dev->hard_header_len + 32, - 0, GFP_KERNEL); + hlen = LL_RESERVED_SPACE(dev); + skb = sock_wmalloc(sk, hlen + sizeof(*ph) + total_len + + dev->needed_tailroom, 0, GFP_KERNEL); if (!skb) { error = -ENOMEM; goto end; } /* Reserve space for headers. */ - skb_reserve(skb, dev->hard_header_len); + skb_reserve(skb, hlen); skb_reset_network_header(skb); skb->dev = dev; @@ -920,7 +921,7 @@ static int __pppoe_xmit(struct sock *sk, /* Copy the data if there is no space for the header or if it's * read-only. */ - if (skb_cow_head(skb, sizeof(*ph) + dev->hard_header_len)) + if (skb_cow_head(skb, LL_RESERVED_SPACE(dev) + sizeof(*ph))) goto abort; __skb_push(skb, sizeof(*ph));