releases/4.19.31/selinux-add-the-missing-walk_size-len-check-in-selinux_sctp_bind_connect.patch

   1 From 292c997a1970f8d1e1dfa354ed770a22f7b5a434 Mon Sep 17 00:00:00 2001
   2 From: Xin Long <lucien.xin@gmail.com>
   3 Date: Sat, 9 Mar 2019 00:07:34 +0800
   4 Subject: selinux: add the missing walk_size + len check in selinux_sctp_bind_connect
   5
   6 From: Xin Long <lucien.xin@gmail.com>
   7
   8 commit 292c997a1970f8d1e1dfa354ed770a22f7b5a434 upstream.
   9
  10 As does in __sctp_connect(), when checking addrs in a while loop, after
  11 get the addr len according to sa_family, it's necessary to do the check
  12 walk_size + af->sockaddr_len > addrs_size to make sure it won't access
  13 an out-of-bounds addr.
  14
  15 The same thing is needed in selinux_sctp_bind_connect(), otherwise an
  16 out-of-bounds issue can be triggered:
  17
  18   [14548.772313] BUG: KASAN: slab-out-of-bounds in selinux_sctp_bind_connect+0x1aa/0x1f0
  19   [14548.927083] Call Trace:
  20   [14548.938072]  dump_stack+0x9a/0xe9
  21   [14548.953015]  print_address_description+0x65/0x22e
  22   [14548.996524]  kasan_report.cold.6+0x92/0x1a6
  23   [14549.015335]  selinux_sctp_bind_connect+0x1aa/0x1f0
  24   [14549.036947]  security_sctp_bind_connect+0x58/0x90
  25   [14549.058142]  __sctp_setsockopt_connectx+0x5a/0x150 [sctp]
  26   [14549.081650]  sctp_setsockopt.part.24+0x1322/0x3ce0 [sctp]
  27
  28 Cc: stable@vger.kernel.org
  29 Fixes: d452930fd3b9 ("selinux: Add SCTP support")
  30 Reported-by: Chunyu Hu <chuhu@redhat.com>
  31 Signed-off-by: Xin Long <lucien.xin@gmail.com>
  32 Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
  33 Signed-off-by: Paul Moore <paul@paul-moore.com>
  34 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  35
  36 ---
  37  security/selinux/hooks.c |    3 +++
  38  1 file changed, 3 insertions(+)
  39
  40 --- a/security/selinux/hooks.c
  41 +++ b/security/selinux/hooks.c
  42 @@ -5334,6 +5334,9 @@ static int selinux_sctp_bind_connect(str
  43                         return -EINVAL;
  44                 }
  45
  46 +               if (walk_size + len > addrlen)
  47 +                       return -EINVAL;
  48 +
  49                 err = -EINVAL;
  50                 switch (optname) {
  51                 /* Bind checks */