From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx49n0Q95/bC6eyZayx0AdK4NKBjAwHlfp1ixsB/zbnBDBxv96kki7VPBhZD51dsbKSiydz0c ARC-Seal: i=1; a=rsa-sha256; t=1522346590; cv=none; d=google.com; s=arc-20160816; b=b37GETo8YNVQVYsIgWB3rj2mOV87uHj8swDvuqQWH5bX8oBkQM23ldhSSk2yGMHniE WhswwxXDbANZajwM9kBA6U4kA2lcxzy8IRK6XapC5fQIsOqtJFSYzE0lFX7jbhPU6JdQ nWk74na1AmJzwrz61kibJcjp5ALzWyCcQ9f/nyp78aQB8OyblA5c7p8cVhDCzT/8VxYo xdT2YLjb66s87H8W2f/IxU8o45ozmttdNzIfX5lHouYIx8fnNpBeK9PaNnmsBw0w9Fw4 V7fsptFrW7h7L0Ty/S2nYUfQeK/SFH3RLre96+FbJeKHdT279bed8AvnoRL2cNxYPoX1 i1hA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=4HTNbCDqRp1PPEzfopqSL/1Qb9kfPSUbeFuNF0rpnQI=; b=SQBdRDKVTs3hB2xwnbnrdcBgPmVxwb2TGjG+LnJ/qU2Qz0VzJUbraWV4rOAlE8mrEu LOrLHMqjJZW3RKLjosCpvsXp1u3Q1iiXVwWINy2jUz77szCloC5cjxsTKK6sd7OUMovO jREBoevzdFPo1g04Ee/QZlUvhhyqFVmbT8WrP5jP/YN5NZ0E6C5Z2R1J+R2OgRWPlbVp SDrbED0zISrLH+oDUHXgVY35iMf2aPOyWbbHVhiV7kwkERaQHuRiPLku9zbk/i8EoALO URjaHDRdI5MCZpwSQu1VmgQsKHNkXkfWPT7b7uw8K37bTL7V9srMEsVYDHYBwfb0whdU C9pQ== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Guillaume Nault , James Chapman , Eric Dumazet , syzbot , "David S. Miller" Subject: [PATCH 4.15 37/47] l2tp: do not accept arbitrary sockets Date: Thu, 29 Mar 2018 20:00:18 +0200 Message-Id: <20180329175732.444312296@linuxfoundation.org> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180329175729.225211114@linuxfoundation.org> References: <20180329175729.225211114@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1596296098194339740?= X-GMAIL-MSGID: =?utf-8?q?1596296098194339740?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 17cfe79a65f98abe535261856c5aef14f306dff7 ] syzkaller found an issue caused by lack of sufficient checks in l2tp_tunnel_create() RAW sockets can not be considered as UDP ones for instance. In another patch, we shall replace all pr_err() by less intrusive pr_debug() so that syzkaller can find other bugs faster. Acked-by: Guillaume Nault Acked-by: James Chapman ================================================================== BUG: KASAN: slab-out-of-bounds in setup_udp_tunnel_sock+0x3ee/0x5f0 net/ipv4/udp_tunnel.c:69 dst_release: dst:00000000d53d0d0f refcnt:-1 Write of size 1 at addr ffff8801d013b798 by task syz-executor3/6242 CPU: 1 PID: 6242 Comm: syz-executor3 Not tainted 4.16.0-rc2+ #253 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23b/0x360 mm/kasan/report.c:412 __asan_report_store1_noabort+0x17/0x20 mm/kasan/report.c:435 setup_udp_tunnel_sock+0x3ee/0x5f0 net/ipv4/udp_tunnel.c:69 l2tp_tunnel_create+0x1354/0x17f0 net/l2tp/l2tp_core.c:1596 pppol2tp_connect+0x14b1/0x1dd0 net/l2tp/l2tp_ppp.c:707 SYSC_connect+0x213/0x4a0 net/socket.c:1640 SyS_connect+0x24/0x30 net/socket.c:1621 do_syscall_64+0x280/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/l2tp/l2tp_core.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -1466,9 +1466,14 @@ int l2tp_tunnel_create(struct net *net, encap = cfg->encap; /* Quick sanity checks */ + err = -EPROTONOSUPPORT; + if (sk->sk_type != SOCK_DGRAM) { + pr_debug("tunl %hu: fd %d wrong socket type\n", + tunnel_id, fd); + goto err; + } switch (encap) { case L2TP_ENCAPTYPE_UDP: - err = -EPROTONOSUPPORT; if (sk->sk_protocol != IPPROTO_UDP) { pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n", tunnel_id, fd, sk->sk_protocol, IPPROTO_UDP); @@ -1476,7 +1481,6 @@ int l2tp_tunnel_create(struct net *net, } break; case L2TP_ENCAPTYPE_IP: - err = -EPROTONOSUPPORT; if (sk->sk_protocol != IPPROTO_L2TP) { pr_err("tunl %hu: fd %d wrong protocol, got %d, expected %d\n", tunnel_id, fd, sk->sk_protocol, IPPROTO_L2TP);