From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48gpB/Ng4wXXvTr2hL2UwXOTPzHPGzL9cGx/BdgvbKMh1boitKVyYU6g3OZqQSM6ExkZR1x ARC-Seal: i=1; a=rsa-sha256; t=1522346780; cv=none; d=google.com; s=arc-20160816; b=AGsWWucI+yZM9amVkMSmxqFoLOntUrX3zA9BS3Ec9kdeW+T0Owu26xdHRKthL/98p4 y3qZuZynY1TPNWXfd7xt6kIz2amrpbJbe9Ryrp6J7e3qTL6MScW2tWcHMaCM556Bgb4W ERLab2JAAHA2S4ybpeIRzPyLBpvBUYibDaqY0CGcA++rv/5Et2kGFWBV57aVclX0Alfo gPHHdVTd5Bk29vsy9DRgsOmPPwkU1EgQLsN76NFU5OmKUvO7rlQUtTvDjTYumABcszoO aPisH9OjLU/NoIV2DJ9LSTqsDrh8iYNCtMCostPhA7PmEGDMOXxPnPxNv2+vKj1KazNU 52kg== 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=eq84ZtsJYyiE+LvhbzKigsCkHIh2tuo0dmsysKy/RYo=; b=MPd+pIfUREsA6956HvPJP60E2kOjFZi9qHRakvIGIJXxVGi4pzpQ3LV+M9umQt3OaU u6UeR6zfF35E4XzI6yyJBhzuM3Yb/tTsIYuLfkRFav0i3M8nmVQNHL/Id60gIxXgMOFl HGvv40othEoefTP6GxL3kuSW5jhCs1DDVvN2zFHhSrEjbXYaGpV/aICSnCoHrdP368tk MJXVryZHD2b94fffklVrBEZmV3XG7WloO3IqRlC2vQeXl+hII8WxEeGrZKmb7dYFjucX NmY3dZVTvtfmpxTmPVgvt3FKzC0XJzTCTjA2+L0CwsrR3o8fbgpXs6xPLlnFkFdY9tPx jK8g== 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 4.9 12/28] l2tp: do not accept arbitrary sockets Date: Thu, 29 Mar 2018 20:00:31 +0200 Message-Id: <20180329175735.001845553@linuxfoundation.org> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180329175733.447823703@linuxfoundation.org> References: <20180329175733.447823703@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?1596296297699707866?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-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 @@ -1612,9 +1612,14 @@ 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); @@ -1622,7 +1627,6 @@ 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);