linux-xiaomi-chiron/net/ipv4
Willem de Bruijn 2efd4fca70 ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull
Syzbot reported a read beyond the end of the skb head when returning
IPV6_ORIGDSTADDR:

  BUG: KMSAN: kernel-infoleak in put_cmsg+0x5ef/0x860 net/core/scm.c:242
  CPU: 0 PID: 4501 Comm: syz-executor128 Not tainted 4.17.0+ #9
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
  Google 01/01/2011
  Call Trace:
    __dump_stack lib/dump_stack.c:77 [inline]
    dump_stack+0x185/0x1d0 lib/dump_stack.c:113
    kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:1125
    kmsan_internal_check_memory+0x138/0x1f0 mm/kmsan/kmsan.c:1219
    kmsan_copy_to_user+0x7a/0x160 mm/kmsan/kmsan.c:1261
    copy_to_user include/linux/uaccess.h:184 [inline]
    put_cmsg+0x5ef/0x860 net/core/scm.c:242
    ip6_datagram_recv_specific_ctl+0x1cf3/0x1eb0 net/ipv6/datagram.c:719
    ip6_datagram_recv_ctl+0x41c/0x450 net/ipv6/datagram.c:733
    rawv6_recvmsg+0x10fb/0x1460 net/ipv6/raw.c:521
    [..]

This logic and its ipv4 counterpart read the destination port from
the packet at skb_transport_offset(skb) + 4.

With MSG_MORE and a local SOCK_RAW sender, syzbot was able to cook a
packet that stores headers exactly up to skb_transport_offset(skb) in
the head and the remainder in a frag.

Call pskb_may_pull before accessing the pointer to ensure that it lies
in skb head.

Link: http://lkml.kernel.org/r/CAF=yD-LEJwZj5a1-bAAj2Oy_hKmGygV6rsJ_WOrAYnv-fnayiQ@mail.gmail.com
Reported-by: syzbot+9adb4b567003cac781f0@syzkaller.appspotmail.com
Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-24 16:35:58 -07:00
..
bpfilter
netfilter
af_inet.c
ah4.c
arp.c
cipso_ipv4.c
datagram.c
devinet.c
esp4.c
esp4_offload.c
fib_frontend.c
fib_lookup.h
fib_notifier.c
fib_rules.c
fib_semantics.c
fib_trie.c
fou.c
gre_demux.c
gre_offload.c
icmp.c
igmp.c multicast: do not restore deleted record source filter mode to new one 2018-07-21 22:58:17 -07:00
inet_connection_sock.c
inet_diag.c
inet_fragment.c
inet_hashtables.c
inet_timewait_sock.c
inetpeer.c
ip_forward.c
ip_fragment.c
ip_gre.c
ip_input.c
ip_options.c
ip_output.c ip: hash fragments consistently 2018-07-23 11:39:30 -07:00
ip_sockglue.c ip: in cmsg IP(V6)_ORIGDSTADDR call pskb_may_pull 2018-07-24 16:35:58 -07:00
ip_tunnel.c
ip_tunnel_core.c
ip_vti.c
ipcomp.c
ipconfig.c
ipip.c
ipmr.c
ipmr_base.c
Kconfig
Makefile
metrics.c
netfilter.c
netlink.c
ping.c
proc.c
protocol.c
raw.c
raw_diag.c
route.c
syncookies.c
sysctl_net_ipv4.c
tcp.c
tcp_bbr.c
tcp_bic.c
tcp_cdg.c
tcp_cong.c
tcp_cubic.c
tcp_dctcp.c tcp: do not delay ACK in DCTCP upon CE status change 2018-07-20 14:32:23 -07:00
tcp_diag.c
tcp_fastopen.c
tcp_highspeed.c
tcp_htcp.c
tcp_hybla.c
tcp_illinois.c
tcp_input.c tcp: add tcp_ooo_try_coalesce() helper 2018-07-23 12:01:36 -07:00
tcp_ipv4.c
tcp_lp.c
tcp_metrics.c
tcp_minisocks.c
tcp_nv.c
tcp_offload.c
tcp_output.c tcp: do not cancel delay-AcK on DCTCP special ACK 2018-07-20 14:32:23 -07:00
tcp_rate.c
tcp_recovery.c
tcp_scalable.c
tcp_timer.c
tcp_ulp.c
tcp_vegas.c
tcp_vegas.h
tcp_veno.c
tcp_westwood.c
tcp_yeah.c
tunnel4.c
udp.c
udp_diag.c
udp_impl.h
udp_offload.c
udp_tunnel.c
udplite.c
xfrm4_input.c
xfrm4_mode_beet.c
xfrm4_mode_transport.c
xfrm4_mode_tunnel.c
xfrm4_output.c
xfrm4_policy.c
xfrm4_protocol.c
xfrm4_state.c
xfrm4_tunnel.c