[PATCH AUTOSEL 5.0 065/173] netfilter: nf_conntrack_h323: restore boundary check correctness

Sasha Levin
2019-06-01T13:21:53Z

From: Jakub Jankowski <shasta@toxcorp.com>

[ Upstream commit f5e85ce8e733c2547827f6268136b70b802eabdb ]

Since commit bc7d811ace4a ("netfilter: nf_ct_h323: Convert
CHECK_BOUND macro to function"), NAT traversal for H.323
doesn't work, failing to parse H323-UserInformation.
nf_h323_error_boundary() compares contents of the bitstring,
not the addresses, preventing valid H.323 packets from being
conntrack'd.

This looks like an oversight from when CHECK_BOUND macro was
converted to a function.

To fix it, stop dereferencing bs->cur and bs->end.

Fixes: bc7d811ace4a ("netfilter: nf_ct_h323: Convert CHECK_BOUND macro to function")
Signed-off-by: Jakub Jankowski <shasta@toxcorp.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nf_conntrack_h323_asn1.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nf_conntrack_h323_asn1.c b/net/netfilter/nf_conntrack_h323_asn1.c
index 1601275efe2d1..4c2ef42e189cb 100644
--- a/net/netfilter/nf_conntrack_h323_asn1.c
+++ b/net/netfilter/nf_conntrack_h323_asn1.c
@@ -172,7 +172,7 @@ static int nf_h323_error_boundary(struct bitstr *bs, size_t bytes, size_t bits)
if (bits % BITS_PER_BYTE > 0)
bytes++;

- if (*bs->cur + bytes > *bs->end)
+ if (bs->cur + bytes > bs->end)
return 1;

return 0;
--
2.20.1