From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-80009.amazon.com (smtp-fw-80009.amazon.com [99.78.197.220]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD3112E848 for ; Thu, 18 Jan 2024 21:59:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=99.78.197.220 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705615150; cv=none; b=NhiMfK+tKRjZJajRNTEJ9ydjXSIdj3cFinUlm0nBOFvCNHe7OM0+/mj/TcItUrN0O+a33xbN1koNrGDQMo03sKuNvP/AQoPVSOxNKYGPk5JkBZmQmpljpIXhB3Wm804OX8CFQf0uokgGOL7qvMSQqpoNsFssulQMcT55Az6FXAU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705615150; c=relaxed/simple; bh=EJhN+IqwWKCT23BLeF+6S4wEJCUV+Sfw0L7IeZlQVn8=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=nSQfdCn9StUBNRpUltXhmb5bmzZmja5Zs7a823Gk3D9fp8U3v+3hyCh5byoF8potEAvHcOF2GTp1K9i4mfZ4EvxGMqDcon74JcNFdm8BBvTSCj/BnA1XTozKGswIxaLu+Z7hIaeZ5p+enAPTfsh+Ms39Smgg13MBXaH3OKuEzos= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.co.jp; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=u0EDWLb2; arc=none smtp.client-ip=99.78.197.220 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.co.jp Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="u0EDWLb2" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1705615148; x=1737151148; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=aDSPsxEpYJ8L3zBHzNtHqrAwEpRufQoOKE9qkdal1QQ=; b=u0EDWLb2sBHmRuQ5wsiffU+7o9DJ5WVz/kwFTbXdcn4WHNnHudxn7GIH RutGfSFlz5G8ixkbomPioIedUdKfXM7A3TyTyoDLSqX9YFRRyc29hj7oY ++TtabzPc82YGKoV2r2eUtCJT1+SEx+hwpqhbRR0OClAhmZfp4tpO0WeO 4=; X-IronPort-AV: E=Sophos;i="6.05,203,1701129600"; d="scan'208";a="59368388" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO email-inbound-relay-pdx-2a-m6i4x-af372327.us-west-2.amazon.com) ([10.25.36.210]) by smtp-border-fw-80009.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jan 2024 21:59:06 +0000 Received: from smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev (pdx2-ws-svc-p26-lb5-vlan2.pdx.amazon.com [10.39.38.66]) by email-inbound-relay-pdx-2a-m6i4x-af372327.us-west-2.amazon.com (Postfix) with ESMTPS id AD85060D01; Thu, 18 Jan 2024 21:59:05 +0000 (UTC) Received: from EX19MTAUWB002.ant.amazon.com [10.0.38.20:15928] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.24.5:2525] with esmtp (Farcaster) id 31194d1a-be10-4acd-82a5-49b1a7cd112f; Thu, 18 Jan 2024 21:59:05 +0000 (UTC) X-Farcaster-Flow-ID: 31194d1a-be10-4acd-82a5-49b1a7cd112f Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX19MTAUWB002.ant.amazon.com (10.250.64.231) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Thu, 18 Jan 2024 21:59:04 +0000 Received: from 88665a182662.ant.amazon.com.com (10.88.183.204) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Thu, 18 Jan 2024 21:59:02 +0000 From: Kuniyuki Iwashima To: CC: , , , , , , Subject: Re: [PATCH net] llc: make llc_ui_sendmsg() more robust against bonding changes Date: Thu, 18 Jan 2024 13:58:54 -0800 Message-ID: <20240118215854.40268-1-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20240118183625.4007013-1-edumazet@google.com> References: <20240118183625.4007013-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: EX19D041UWA002.ant.amazon.com (10.13.139.121) To EX19D004ANA001.ant.amazon.com (10.37.240.138) Precedence: Bulk From: Eric Dumazet Date: Thu, 18 Jan 2024 18:36:25 +0000 > syzbot was able to trick llc_ui_sendmsg(), allocating an skb with no > headroom, but subsequently trying to push 14 bytes of Ethernet header [1] > > Like some others, llc_ui_sendmsg() releases the socket lock before > calling sock_alloc_send_skb(). > Then it acquires it again, but does not redo all the sanity checks > that were performed. > > This fix: > > - Uses LL_RESERVED_SPACE() to reserve space. > - Check all conditions again after socket lock is held again. > - Do not account Ethernet header for mtu limitation. > > [1] > > skbuff: skb_under_panic: text:ffff800088baa334 len:1514 put:14 head:ffff0000c9c37000 data:ffff0000c9c36ff2 tail:0x5dc end:0x6c0 dev:bond0 > > kernel BUG at net/core/skbuff.c:193 ! > Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP > Modules linked in: > CPU: 0 PID: 6875 Comm: syz-executor.0 Not tainted 6.7.0-rc8-syzkaller-00101-g0802e17d9aca-dirty #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 > pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : skb_panic net/core/skbuff.c:189 [inline] > pc : skb_under_panic+0x13c/0x140 net/core/skbuff.c:203 > lr : skb_panic net/core/skbuff.c:189 [inline] > lr : skb_under_panic+0x13c/0x140 net/core/skbuff.c:203 > sp : ffff800096f97000 > x29: ffff800096f97010 x28: ffff80008cc8d668 x27: dfff800000000000 > x26: ffff0000cb970c90 x25: 00000000000005dc x24: ffff0000c9c36ff2 > x23: ffff0000c9c37000 x22: 00000000000005ea x21: 00000000000006c0 > x20: 000000000000000e x19: ffff800088baa334 x18: 1fffe000368261ce > x17: ffff80008e4ed000 x16: ffff80008a8310f8 x15: 0000000000000001 > x14: 1ffff00012df2d58 x13: 0000000000000000 x12: 0000000000000000 > x11: 0000000000000001 x10: 0000000000ff0100 x9 : e28a51f1087e8400 > x8 : e28a51f1087e8400 x7 : ffff80008028f8d0 x6 : 0000000000000000 > x5 : 0000000000000001 x4 : 0000000000000001 x3 : ffff800082b78714 > x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000089 > Call trace: > skb_panic net/core/skbuff.c:189 [inline] > skb_under_panic+0x13c/0x140 net/core/skbuff.c:203 > skb_push+0xf0/0x108 net/core/skbuff.c:2451 > eth_header+0x44/0x1f8 net/ethernet/eth.c:83 > dev_hard_header include/linux/netdevice.h:3188 [inline] > llc_mac_hdr_init+0x110/0x17c net/llc/llc_output.c:33 > llc_sap_action_send_xid_c+0x170/0x344 net/llc/llc_s_ac.c:85 > llc_exec_sap_trans_actions net/llc/llc_sap.c:153 [inline] > llc_sap_next_state net/llc/llc_sap.c:182 [inline] > llc_sap_state_process+0x1ec/0x774 net/llc/llc_sap.c:209 > llc_build_and_send_xid_pkt+0x12c/0x1c0 net/llc/llc_sap.c:270 > llc_ui_sendmsg+0x7bc/0xb1c net/llc/af_llc.c:997 > sock_sendmsg_nosec net/socket.c:730 [inline] > __sock_sendmsg net/socket.c:745 [inline] > sock_sendmsg+0x194/0x274 net/socket.c:767 > splice_to_socket+0x7cc/0xd58 fs/splice.c:881 > do_splice_from fs/splice.c:933 [inline] > direct_splice_actor+0xe4/0x1c0 fs/splice.c:1142 > splice_direct_to_actor+0x2a0/0x7e4 fs/splice.c:1088 > do_splice_direct+0x20c/0x348 fs/splice.c:1194 > do_sendfile+0x4bc/0xc70 fs/read_write.c:1254 > __do_sys_sendfile64 fs/read_write.c:1322 [inline] > __se_sys_sendfile64 fs/read_write.c:1308 [inline] > __arm64_sys_sendfile64+0x160/0x3b4 fs/read_write.c:1308 > __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline] > invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:51 > el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:136 > do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:155 > el0_svc+0x54/0x158 arch/arm64/kernel/entry-common.c:678 > el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:696 > el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:595 > Code: aa1803e6 aa1903e7 a90023f5 94792f6a (d4210000) > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Reported-and-tested-by: syzbot+2a7024e9502df538e8ef@syzkaller.appspotmail.com > Signed-off-by: Eric Dumazet > --- > net/llc/af_llc.c | 24 ++++++++++++++++-------- > 1 file changed, 16 insertions(+), 8 deletions(-) > > diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c > index 9b06c380866b53bcb395bf255587279db025d11d..20551cfb7da6d8dd098c906477895e26c080fe32 100644 > --- a/net/llc/af_llc.c > +++ b/net/llc/af_llc.c > @@ -928,14 +928,15 @@ static int llc_ui_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, > */ > static int llc_ui_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) > { > + DECLARE_SOCKADDR(struct sockaddr_llc *, addr, msg->msg_name); > struct sock *sk = sock->sk; > struct llc_sock *llc = llc_sk(sk); > - DECLARE_SOCKADDR(struct sockaddr_llc *, addr, msg->msg_name); > int flags = msg->msg_flags; > int noblock = flags & MSG_DONTWAIT; > + int rc = -EINVAL, copied = 0, hdrlen, hh_len; > struct sk_buff *skb = NULL; > + struct net_device *dev; > size_t size = 0; > - int rc = -EINVAL, copied = 0, hdrlen; > > dprintk("%s: sending from %02X to %02X\n", __func__, > llc->laddr.lsap, llc->daddr.lsap); > @@ -955,22 +956,29 @@ static int llc_ui_sendmsg(struct socket *sock, struct msghdr *msg, size_t len) > if (rc) > goto out; > } > - hdrlen = llc->dev->hard_header_len + llc_ui_header_len(sk, addr); > + dev = llc->dev; > + hh_len = LL_RESERVED_SPACE(dev); > + hdrlen = llc_ui_header_len(sk, addr); > size = hdrlen + len; > - if (size > llc->dev->mtu) > - size = llc->dev->mtu; > + size = min_t(size_t, size, READ_ONCE(dev->mtu)); > copied = size - hdrlen; > rc = -EINVAL; > if (copied < 0) > goto out; > release_sock(sk); > - skb = sock_alloc_send_skb(sk, size, noblock, &rc); > + skb = sock_alloc_send_skb(sk, hh_len + size, noblock, &rc); > lock_sock(sk); > if (!skb) > goto out; > - skb->dev = llc->dev; > + if (sock_flag(sk, SOCK_ZAPPED) || Probably we need not check SOCK_ZAPPED again after llc_ui_autobind() ? > + llc->dev != dev || > + hdrlen != llc_ui_header_len(sk, addr) || > + hh_len != LL_RESERVED_SPACE(dev) || > + size > READ_ONCE(dev->mtu)) > + goto out; > + skb->dev = dev; > skb->protocol = llc_proto_type(addr->sllc_arphrd); > - skb_reserve(skb, hdrlen); > + skb_reserve(skb, hh_len + hdrlen); > rc = memcpy_from_msg(skb_put(skb, copied), msg, copied); > if (rc) > goto out; > -- > 2.43.0.429.g432eaa2c6b-goog