releases/4.4.133/sctp-handle-two-v4-addrs-comparison-in-sctp_inet6_cmp_addr.patch

   1 From foo@baz Wed May 16 16:57:32 CEST 2018
   2 From: Xin Long <lucien.xin@gmail.com>
   3 Date: Thu, 26 Apr 2018 14:13:57 +0800
   4 Subject: sctp: handle two v4 addrs comparison in sctp_inet6_cmp_addr
   5
   6 From: Xin Long <lucien.xin@gmail.com>
   7
   8 [ Upstream commit d625329b06e46bd20baf9ee40847d11982569204 ]
   9
  10 Since sctp ipv6 socket also supports v4 addrs, it's possible to
  11 compare two v4 addrs in pf v6 .cmp_addr, sctp_inet6_cmp_addr.
  12
  13 However after Commit 1071ec9d453a ("sctp: do not check port in
  14 sctp_inet6_cmp_addr"), it no longer calls af1->cmp_addr, which
  15 in this case is sctp_v4_cmp_addr, but calls __sctp_v6_cmp_addr
  16 where it handles them as two v6 addrs. It would cause a out of
  17 bounds crash.
  18
  19 syzbot found this crash when trying to bind two v4 addrs to a
  20 v6 socket.
  21
  22 This patch fixes it by adding the process for two v4 addrs in
  23 sctp_inet6_cmp_addr.
  24
  25 Fixes: 1071ec9d453a ("sctp: do not check port in sctp_inet6_cmp_addr")
  26 Reported-by: syzbot+cd494c1dd681d4d93ebb@syzkaller.appspotmail.com
  27 Signed-off-by: Xin Long <lucien.xin@gmail.com>
  28 Acked-by: Neil Horman <nhorman@tuxdriver.com>
  29 Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
  30 Signed-off-by: David S. Miller <davem@davemloft.net>
  31 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  32 ---
  33  net/sctp/ipv6.c |    3 +++
  34  1 file changed, 3 insertions(+)
  35
  36 --- a/net/sctp/ipv6.c
  37 +++ b/net/sctp/ipv6.c
  38 @@ -863,6 +863,9 @@ static int sctp_inet6_cmp_addr(const uni
  39         if (sctp_is_any(sk, addr1) || sctp_is_any(sk, addr2))
  40                 return 1;
  41
  42 +       if (addr1->sa.sa_family == AF_INET && addr2->sa.sa_family == AF_INET)
  43 +               return addr1->v4.sin_addr.s_addr == addr2->v4.sin_addr.s_addr;
  44 +
  45         return __sctp_v6_cmp_addr(addr1, addr2);
  46  }
  47