queue-4.19/netfilter-nf_conntrack_h323-restore-boundary-check-c.patch

   1 From 0c6d6813636c21d797a1c3b3b70bac78277ed535 Mon Sep 17 00:00:00 2001
   2 From: Jakub Jankowski <shasta@toxcorp.com>
   3 Date: Thu, 25 Apr 2019 23:46:50 +0200
   4 Subject: netfilter: nf_conntrack_h323: restore boundary check correctness
   5
   6 [ Upstream commit f5e85ce8e733c2547827f6268136b70b802eabdb ]
   7
   8 Since commit bc7d811ace4a ("netfilter: nf_ct_h323: Convert
   9 CHECK_BOUND macro to function"), NAT traversal for H.323
  10 doesn't work, failing to parse H323-UserInformation.
  11 nf_h323_error_boundary() compares contents of the bitstring,
  12 not the addresses, preventing valid H.323 packets from being
  13 conntrack'd.
  14
  15 This looks like an oversight from when CHECK_BOUND macro was
  16 converted to a function.
  17
  18 To fix it, stop dereferencing bs->cur and bs->end.
  19
  20 Fixes: bc7d811ace4a ("netfilter: nf_ct_h323: Convert CHECK_BOUND macro to function")
  21 Signed-off-by: Jakub Jankowski <shasta@toxcorp.com>
  22 Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
  23 Signed-off-by: Sasha Levin <sashal@kernel.org>
  24 ---
  25  net/netfilter/nf_conntrack_h323_asn1.c | 2 +-
  26  1 file changed, 1 insertion(+), 1 deletion(-)
  27
  28 diff --git a/net/netfilter/nf_conntrack_h323_asn1.c b/net/netfilter/nf_conntrack_h323_asn1.c
  29 index 1601275efe2d..4c2ef42e189c 100644
  30 --- a/net/netfilter/nf_conntrack_h323_asn1.c
  31 +++ b/net/netfilter/nf_conntrack_h323_asn1.c
  32 @@ -172,7 +172,7 @@ static int nf_h323_error_boundary(struct bitstr *bs, size_t bytes, size_t bits)
  33         if (bits % BITS_PER_BYTE > 0)
  34                 bytes++;
  35
  36 -       if (*bs->cur + bytes > *bs->end)
  37 +       if (bs->cur + bytes > bs->end)
  38                 return 1;
  39
  40         return 0;
  41 --
  42 2.20.1
  43