diff options
author | Darrell Ball <dlu998@gmail.com> | 2019-01-15 18:58:17 -0800 |
---|---|---|
committer | Ben Pfaff <blp@ovn.org> | 2019-01-18 16:16:17 -0800 |
commit | d13d711503595c0265ebf58f68250bbc9225ee9b (patch) | |
tree | c54bed04b9e6f0a44e2b404dab4a8227c7d801be /lib/conntrack.c | |
parent | efa29a891031431fb1e69026f3e4d6c17f6f92c2 (diff) | |
download | openvswitch-d13d711503595c0265ebf58f68250bbc9225ee9b.tar.gz |
conntrack: Fix FTP seq_skew boundary adjustments.
At the same time, splice out a function and also rely on the compiler
for overflow/underflow handling.
Found by inspection.
Fixes: bd5e81a0e596 ("Userspace Datapath: Add ALG infra and FTP.")
Signed-off-by: Darrell Ball <dlu998@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
Diffstat (limited to 'lib/conntrack.c')
-rw-r--r-- | lib/conntrack.c | 38 |
1 files changed, 10 insertions, 28 deletions
diff --git a/lib/conntrack.c b/lib/conntrack.c index c6864b9eb..f732b9ee4 100644 --- a/lib/conntrack.c +++ b/lib/conntrack.c @@ -3176,6 +3176,13 @@ repl_ftp_v6_addr(struct dp_packet *pkt, struct ct_addr v6_addr_rep, return overall_delta; } +/* Increment/decrement a TCP sequence number. */ +static void +adj_seqnum(ovs_16aligned_be32 *val, int32_t inc) +{ + put_16aligned_be32(val, htonl(ntohl(get_16aligned_be32(val)) + inc)); +} + static void handle_ftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx, struct dp_packet *pkt, const struct conn *ec, long long now, @@ -3250,34 +3257,9 @@ handle_ftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx, struct tcp_header *th = dp_packet_l4(pkt); if (nat && ec->seq_skew != 0) { - if (ctx->reply != ec->seq_skew_dir) { - - uint32_t tcp_ack = ntohl(get_16aligned_be32(&th->tcp_ack)); - - if ((ec->seq_skew > 0) && (tcp_ack < ec->seq_skew)) { - /* Should not be possible; will be marked invalid. */ - tcp_ack = 0; - } else if ((ec->seq_skew < 0) && - (UINT32_MAX - tcp_ack < -ec->seq_skew)) { - tcp_ack = (-ec->seq_skew) - (UINT32_MAX - tcp_ack); - } else { - tcp_ack -= ec->seq_skew; - } - ovs_be32 new_tcp_ack = htonl(tcp_ack); - put_16aligned_be32(&th->tcp_ack, new_tcp_ack); - } else { - uint32_t tcp_seq = ntohl(get_16aligned_be32(&th->tcp_seq)); - if ((ec->seq_skew > 0) && (UINT32_MAX - tcp_seq < ec->seq_skew)) { - tcp_seq = ec->seq_skew - (UINT32_MAX - tcp_seq); - } else if ((ec->seq_skew < 0) && (tcp_seq < -ec->seq_skew)) { - /* Should not be possible; will be marked invalid. */ - tcp_seq = 0; - } else { - tcp_seq += ec->seq_skew; - } - ovs_be32 new_tcp_seq = htonl(tcp_seq); - put_16aligned_be32(&th->tcp_seq, new_tcp_seq); - } + ctx->reply != ec->seq_skew_dir ? + adj_seqnum(&th->tcp_ack, -ec->seq_skew) : + adj_seqnum(&th->tcp_seq, ec->seq_skew); } th->tcp_csum = 0; |