[ovs-dev] [patch_v6 1/5] Userspace Datapath: Add ALG infra and FTP.
Darrell Ball
dball at vmware.com
Sun Jul 16 20:35:58 UTC 2017
I made an incremental change locally for Windows/AppVeyor build support.
#ifndef _WIN32
if (strncasecmp(ftp_msg, FTP_EPRT_CMD, strlen(FTP_EPRT_CMD)) &&
!strcasestr(ftp_msg, FTP_EPSV_REPLY)) {
return CT_FTP_CTL_OTHER;
}
#else
/* Windows/AppVeyor does not know about strcasestr; since this file
* is not actually used on Windows, just assume standard message
* case on Windows. */
if (strncasecmp(ftp_msg, FTP_EPRT_CMD, strlen(FTP_EPRT_CMD)) &&
!strstr(ftp_msg, "Extended Passive")) {
return CT_FTP_CTL_OTHER;
}
#endif
Darrell
On 7/15/17, 12:49 PM, "ovs-dev-bounces at openvswitch.org on behalf of Darrell Ball" <ovs-dev-bounces at openvswitch.org on behalf of dlu998 at gmail.com> wrote:
ALG infra and FTP (both V4 and V6) support is added to the userspace
datapath. Also, NAT support is included.
Signed-off-by: Darrell Ball <dlu998 at gmail.com>
---
lib/conntrack-private.h | 35 +-
lib/conntrack.c | 1051 +++++++++++++++++++++++++++++++++++++++++++----
lib/conntrack.h | 10 +-
3 files changed, 1023 insertions(+), 73 deletions(-)
diff --git a/lib/conntrack-private.h b/lib/conntrack-private.h
index 55084d3..d61b0e1 100644
--- a/lib/conntrack-private.h
+++ b/lib/conntrack-private.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015, 2016 Nicira, Inc.
+ * Copyright (c) 2015, 2016, 2017 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -62,17 +62,50 @@ struct nat_conn_key_node {
struct conn_key value;
};
+/* This is used for alg expectations; an expectation is a
+ * context created in preparation for establishing a data
+ * connection. The expectation is created by the control
+ * connection. */
+struct alg_exp_node {
+ struct hmap_node node;
+ /* Expiry list node for an expectation. */
+ struct ovs_list exp_node;
+ /* The time when this expectation will expire. */
+ long long expiration;
+ /* Key of data connection to be created. */
+ struct conn_key key;
+ /* Corresponding key of the control connection. */
+ struct conn_key master_key;
+ /* The NAT replacement address to be used by the data connection. */
+ struct ct_addr alg_nat_repl_addr;
+ /* The data connection inherits the master control
+ * connection label and mark. */
+ ovs_u128 master_label;
+ uint32_t master_mark;
+ /* True if the expectation is for passive mode, as is
+ * one option for FTP. */
+ bool passive_mode;
+};
+
struct conn {
struct conn_key key;
struct conn_key rev_key;
+ /* Only used for orig_tuple support. */
+ struct conn_key master_key;
long long expiration;
struct ovs_list exp_node;
struct hmap_node node;
ovs_u128 label;
/* XXX: consider flattening. */
struct nat_action_info_t *nat_info;
+ char *alg;
+ int seq_skew;
uint32_t mark;
uint8_t conn_type;
+ /* TCP sequence skew due to NATTing of FTP control messages. */
+ uint8_t seq_skew_dir;
+ /* True if alg data connection. */
+ uint8_t alg_related;
};
enum ct_update_res {
diff --git a/lib/conntrack.c b/lib/conntrack.c
index de46a6b..8c4aa60 100644
--- a/lib/conntrack.c
+++ b/lib/conntrack.c
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015, 2016 Nicira, Inc.
+ * Copyright (c) 2015, 2016, 2017 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -15,14 +15,14 @@
*/
#include <config.h>
-#include "conntrack.h"
-
+#include <ctype.h>
#include <errno.h>
-#include <sys/types.h>
#include <netinet/in.h>
#include <netinet/icmp6.h>
+#include <sys/types.h>
#include "bitmap.h"
+#include "conntrack.h"
#include "conntrack-private.h"
#include "coverage.h"
#include "csum.h"
@@ -39,7 +39,6 @@
#include "random.h"
#include "timeval.h"
-
VLOG_DEFINE_THIS_MODULE(conntrack);
COVERAGE_DEFINE(conntrack_full);
@@ -53,6 +52,19 @@ struct conn_lookup_ctx {
bool icmp_related;
};
+enum ftp_ctl_pkt {
+ /* Control packets with address and/or port specifiers. */
+ CT_FTP_CTL_INTEREST,
+ /* Control packets without address and/or port specifiers. */
+ CT_FTP_CTL_OTHER,
+ CT_FTP_CTL_INVALID,
+};
+
+enum ct_alg_mode {
+ CT_FTP_MODE_ACTIVE,
+ CT_FTP_MODE_PASSIVE,
+};
+
static bool conn_key_extract(struct conntrack *, struct dp_packet *,
ovs_be16 dl_type, struct conn_lookup_ctx *,
uint16_t zone);
@@ -102,6 +114,33 @@ static inline bool
extract_l3_ipv6(struct conn_key *key, const void *data, size_t size,
const char **new_data);
+static struct alg_exp_node *
+expectation_lookup(struct hmap *alg_expectations,
+ const struct conn_key *key, uint32_t basis);
+
+static int
+repl_ftp_v4_addr(struct dp_packet *pkt, ovs_be32 v4_addr_rep,
+ char *ftp_data_v4_start,
+ size_t addr_offset_from_ftp_data_start);
+
+static enum ftp_ctl_pkt
+process_ftp_ctl_v4(struct conntrack *ct,
+ struct dp_packet *pkt,
+ const struct conn *conn_for_expectation,
+ long long now, ovs_be32 *v4_addr_rep,
+ char **ftp_data_v4_start,
+ size_t *addr_offset_from_ftp_data_start);
+
+static enum ftp_ctl_pkt
+detect_ftp_ctl_type(const struct conn_lookup_ctx *ctx,
+ struct dp_packet *pkt);
+
+static void
+handle_ftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx,
+ struct dp_packet *pkt,
+ const struct conn *conn_for_expectation,
+ long long now, enum ftp_ctl_pkt ftp_ctl, bool nat);
+
static struct ct_l4_proto *l4_protos[] = {
[IPPROTO_TCP] = &ct_proto_tcp,
[IPPROTO_UDP] = &ct_proto_other,
@@ -115,6 +154,36 @@ long long ct_timeout_val[] = {
#undef CT_TIMEOUT
};
+/* The maximum TCP or UDP port number. */
+#define CT_MAX_L4_PORT 65535
+/* Alg expectation timeout. */
+#define CT_ALG_EXP_TIMEOUT (30 * 1000)
+/* String buffer used for parsing FTP string messages.
+ * This is sized about twice what is needed to leave some
+ * margin of error. */
+#define LARGEST_FTP_MSG_OF_INTEREST 128
+/* FTP port string used in active mode. */
+#define FTP_PORT_CMD "PORT"
+/* FTP pasv string used in passive mode. */
+#define FTP_PASV_REPLY_CODE "227"
+/* Maximum decimal digits for port in FTP command.
+ * The port is represented as two 3 digit numbers with the
+ * high part a multiple of 256. */
+#define MAX_FTP_PORT_DGTS 3
+
+/* FTP extension EPRT string used for active mode. */
+#define FTP_EPRT_CMD "EPRT"
+/* FTP extension EPSV string used for passive mode. */
+#define FTP_EPSV_REPLY "EXTENDED PASSIVE"
+/* Maximum decimal digits for port in FTP extended command. */
+#define MAX_EXT_FTP_PORT_DGTS 5
+/* FTP extended command code for IPv6. */
+#define FTP_AF_V6 '2'
+/* Used to indicate a wildcard L4 source port number for ALGs.
+ * This is used for port numbers that we cannot predict in
+ * expectations. */
+#define ALG_WC_SRC_PORT 0
+
/* If the total number of connections goes above this value, no new connections
* are accepted; this is for CT_CONN_TYPE_DEFAULT connections. */
#define DEFAULT_N_CONN_LIMIT 3000000
@@ -130,6 +199,8 @@ conntrack_init(struct conntrack *ct)
ct_rwlock_init(&ct->resources_lock);
ct_rwlock_wrlock(&ct->resources_lock);
hmap_init(&ct->nat_conn_keys);
+ hmap_init(&ct->alg_expectations);
+ ovs_list_init(&ct->alg_exp_list);
ct_rwlock_unlock(&ct->resources_lock);
for (i = 0; i < CONNTRACK_BUCKETS; i++) {
@@ -169,7 +240,7 @@ conntrack_destroy(struct conntrack *ct)
ovs_mutex_destroy(&ctb->cleanup_mutex);
ct_lock_lock(&ctb->lock);
- HMAP_FOR_EACH_POP(conn, node, &ctb->connections) {
+ HMAP_FOR_EACH_POP (conn, node, &ctb->connections) {
if (conn->conn_type == CT_CONN_TYPE_DEFAULT) {
atomic_count_dec(&ct->n_conn);
}
@@ -185,6 +256,13 @@ conntrack_destroy(struct conntrack *ct)
free(nat_conn_key_node);
}
hmap_destroy(&ct->nat_conn_keys);
+
+ struct alg_exp_node *alg_exp_node;
+ HMAP_FOR_EACH_POP (alg_exp_node, node, &ct->alg_expectations) {
+ free(alg_exp_node);
+ }
+ ovs_list_poison(&ct->alg_exp_list);
+ hmap_destroy(&ct->alg_expectations);
ct_rwlock_unlock(&ct->resources_lock);
ct_rwlock_destroy(&ct->resources_lock);
}
@@ -200,7 +278,7 @@ static unsigned hash_to_bucket(uint32_t hash)
static void
write_ct_md(struct dp_packet *pkt, uint16_t zone, const struct conn *conn,
- const struct conn_key *key)
+ const struct conn_key *key, const struct alg_exp_node *alg_exp)
{
pkt->md.ct_state |= CS_TRACKED;
pkt->md.ct_zone = zone;
@@ -209,11 +287,20 @@ write_ct_md(struct dp_packet *pkt, uint16_t zone, const struct conn *conn,
/* Use the original direction tuple if we have it. */
if (conn) {
- key = &conn->key;
+ if (conn->alg_related) {
+ key = &conn->master_key;
+ } else {
+ key = &conn->key;
+ }
+ } else if (alg_exp) {
+ pkt->md.ct_mark = alg_exp->master_mark;
+ pkt->md.ct_label = alg_exp->master_label;
+ key = &alg_exp->master_key;
}
pkt->md.ct_orig_tuple_ipv6 = false;
if (key) {
if (key->dl_type == htons(ETH_TYPE_IP)) {
+
pkt->md.ct_orig_tuple.ipv4 = (struct ovs_key_ct_tuple_ipv4) {
key->src.addr.ipv4_aligned,
key->dst.addr.ipv4_aligned,
@@ -238,7 +325,50 @@ write_ct_md(struct dp_packet *pkt, uint16_t zone, const struct conn *conn,
} else {
memset(&pkt->md.ct_orig_tuple, 0, sizeof pkt->md.ct_orig_tuple);
}
+}
+
+static uint8_t
+get_ip_proto(const struct dp_packet *pkt)
+{
+
+ uint8_t ip_proto;
+ struct eth_header *l2 = dp_packet_eth(pkt);
+ if (l2->eth_type == htons(ETH_TYPE_IPV6)) {
+ struct ovs_16aligned_ip6_hdr *nh6 = dp_packet_l3(pkt);
+ ip_proto = nh6->ip6_ctlun.ip6_un1.ip6_un1_nxt;
+ } else {
+ struct ip_header *l3_hdr = dp_packet_l3(pkt);
+ ip_proto = l3_hdr->ip_proto;
+ }
+
+ return ip_proto;
+}
+
+static bool
+is_ftp_ctl(const struct dp_packet *pkt)
+{
+ uint8_t ip_proto = get_ip_proto(pkt);
+ struct tcp_header *th = dp_packet_l4(pkt);
+
+ /* CT_IPPORT_FTP is used because IPPORT_FTP in not defined in OSX,
+ * at least in in.h. Since this value will never change, just remove
+ * the external dependency. */
+#define CT_IPPORT_FTP 21
+ return (ip_proto == IPPROTO_TCP &&
+ (th->tcp_src == htons(CT_IPPORT_FTP) ||
+ th->tcp_dst == htons(CT_IPPORT_FTP)));
+
+}
+
+static void
+alg_exp_init_expiration(struct conntrack *ct,
+ struct alg_exp_node *alg_exp_node,
+ long long now)
+ OVS_REQ_WRLOCK(ct->resources_lock)
+{
+ alg_exp_node->expiration = now + CT_ALG_EXP_TIMEOUT;
+ ovs_list_push_back(&ct->alg_exp_list, &alg_exp_node->exp_node);
}
static void
@@ -363,8 +493,8 @@ reverse_nat_packet(struct dp_packet *pkt, const struct conn *conn)
struct ip_header *nh = dp_packet_l3(pkt);
struct icmp_header *icmp = dp_packet_l4(pkt);
struct ip_header *inner_l3 = (struct ip_header *) (icmp + 1);
- extract_l3_ipv4(&inner_key, inner_l3, tail - ((char *)inner_l3)
- -pad, &inner_l4, false);
+ extract_l3_ipv4(&inner_key, inner_l3, tail - ((char *)inner_l3) - pad,
+ &inner_l4, false);
pkt->l3_ofs += (char *) inner_l3 - (char *) nh;
pkt->l4_ofs += inner_l4 - (char *) icmp;
@@ -459,7 +589,7 @@ un_nat_packet(struct dp_packet *pkt, const struct conn *conn,
* and a hash would have already been needed. Hence, this function
* is just intended for code clarity. */
static struct conn *
-conn_lookup(struct conntrack *ct, struct conn_key *key, long long now)
+conn_lookup(struct conntrack *ct, const struct conn_key *key, long long now)
{
struct conn_lookup_ctx ctx;
ctx.conn = NULL;
@@ -471,6 +601,21 @@ conn_lookup(struct conntrack *ct, struct conn_key *key, long long now)
}
static void
+conn_seq_skew_set(struct conntrack *ct, const struct conn_key *key,
+ long long now, int seq_skew, bool seq_skew_dir)
+{
+ uint32_t hash = conn_key_hash(key, ct->hash_basis);
+ unsigned bucket = hash_to_bucket(hash);
+ ct_lock_lock(&ct->buckets[bucket].lock);
+ struct conn *conn = conn_lookup(ct, key, now);
+ if (conn && seq_skew) {
+ conn->seq_skew = seq_skew;
+ conn->seq_skew_dir = seq_skew_dir;
+ }
+ ct_lock_unlock(&ct->buckets[bucket].lock);
+}
+
+static void
nat_clean(struct conntrack *ct, struct conn *conn,
struct conntrack_bucket *ctb)
OVS_REQUIRES(ctb->lock)
@@ -529,7 +674,9 @@ static struct conn *
conn_not_found(struct conntrack *ct, struct dp_packet *pkt,
struct conn_lookup_ctx *ctx, bool commit, long long now,
const struct nat_action_info_t *nat_action_info,
- struct conn *conn_for_un_nat_copy)
+ struct conn *conn_for_un_nat_copy,
+ const char *helper,
+ const struct alg_exp_node *alg_exp)
{
unsigned bucket = hash_to_bucket(ctx->hash);
struct conn *nc = NULL;
@@ -539,6 +686,9 @@ conn_not_found(struct conntrack *ct, struct dp_packet *pkt,
return nc;
}
pkt->md.ct_state = CS_NEW;
+ if (alg_exp) {
+ pkt->md.ct_state |= CS_RELATED;
+ }
if (commit) {
unsigned int n_conn_limit;
@@ -555,35 +705,72 @@ conn_not_found(struct conntrack *ct, struct dp_packet *pkt,
nc->rev_key = nc->key;
conn_key_reverse(&nc->rev_key);
+ if (helper) {
+ nc->alg = xstrdup(helper);
+ }
+
+ if (alg_exp) {
+ nc->alg_related = true;
+ nc->mark = alg_exp->master_mark;
+ nc->label = alg_exp->master_label;
+ nc->master_key = alg_exp->master_key;
+ }
+
if (nat_action_info) {
nc->nat_info = xmemdup(nat_action_info, sizeof *nc->nat_info);
- ct_rwlock_wrlock(&ct->resources_lock);
- bool nat_res = nat_select_range_tuple(ct, nc,
- conn_for_un_nat_copy);
+ if (alg_exp) {
+ if (alg_exp->passive_mode) {
+ nc->rev_key.dst.addr = alg_exp->alg_nat_repl_addr;
+ nc->nat_info->nat_action = NAT_ACTION_SRC;
+ } else {
+ nc->rev_key.src.addr = alg_exp->alg_nat_repl_addr;
+ nc->nat_info->nat_action = NAT_ACTION_DST;
+ }
+ *conn_for_un_nat_copy = *nc;
+ } else {
+ *conn_for_un_nat_copy = *nc;
+ ct_rwlock_wrlock(&ct->resources_lock);
+ bool nat_res = nat_select_range_tuple(
+ ct, nc, conn_for_un_nat_copy);
- if (!nat_res) {
- free(nc->nat_info);
- nc->nat_info = NULL;
- free (nc);
- ct_rwlock_unlock(&ct->resources_lock);
- return NULL;
- }
+ if (!nat_res) {
+ goto nat_res_exhaustion;
+ }
- if (conn_for_un_nat_copy &&
- nc->conn_type == CT_CONN_TYPE_DEFAULT) {
+ /* Update nc with nat adjustments made to
+ * conn_for_un_nat_copy by nat_select_range_tuple(). */
*nc = *conn_for_un_nat_copy;
- conn_for_un_nat_copy->conn_type = CT_CONN_TYPE_UN_NAT;
- conn_for_un_nat_copy->nat_info = NULL;
+ ct_rwlock_unlock(&ct->resources_lock);
}
- ct_rwlock_unlock(&ct->resources_lock);
-
+ conn_for_un_nat_copy->conn_type = CT_CONN_TYPE_UN_NAT;
+ conn_for_un_nat_copy->nat_info = NULL;
+ conn_for_un_nat_copy->alg = NULL;
nat_packet(pkt, nc, ctx->icmp_related);
}
hmap_insert(&ct->buckets[bucket].connections, &nc->node, ctx->hash);
atomic_count_inc(&ct->n_conn);
}
+
return nc;
+
+ /* This would be a user error or a DOS attack.
+ * A user error is prevented by allocating enough
+ * combinations of NAT addresses when combined with
+ * ephemeral ports. A DOS attack should be protected
+ * against with firewall rules or a separate firewall.
+ * Also using zone partitioning can limit DoS impact. */
+nat_res_exhaustion:
+ delete_conn(nc);
+ /* conn_for_un_nat_copy is a local variable in process_one; this
+ * memset() serves to document that conn_for_un_nat_copy is from
+ * this point on unused. */
+ memset(conn_for_un_nat_copy, 0, sizeof *conn_for_un_nat_copy);
+ ct_rwlock_unlock(&ct->resources_lock);
+ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
+ VLOG_WARN_RL(&rl, "Unable to NAT due to tuple space exhaustion - "
+ "if DoS attack, use firewalling and/or zone partitioning.");
+ return NULL;
}
static bool
@@ -600,6 +787,9 @@ conn_update_state(struct conntrack *ct, struct dp_packet *pkt,
pkt->md.ct_state |= CS_REPLY_DIR;
}
} else {
+ if ((*conn)->alg_related) {
+ pkt->md.ct_state |= CS_RELATED;
+ }
enum ct_update_res res = conn_update(*conn, &ct->buckets[bucket],
pkt, ctx->reply, now);
@@ -627,7 +817,7 @@ conn_update_state(struct conntrack *ct, struct dp_packet *pkt,
static void
create_un_nat_conn(struct conntrack *ct, struct conn *conn_for_un_nat_copy,
- long long now)
+ long long now, bool alg_un_nat)
{
struct conn *nc = xmemdup(conn_for_un_nat_copy, sizeof *nc);
nc->key = conn_for_un_nat_copy->rev_key;
@@ -635,22 +825,26 @@ create_un_nat_conn(struct conntrack *ct, struct conn *conn_for_un_nat_copy,
uint32_t un_nat_hash = conn_key_hash(&nc->key, ct->hash_basis);
unsigned un_nat_conn_bucket = hash_to_bucket(un_nat_hash);
ct_lock_lock(&ct->buckets[un_nat_conn_bucket].lock);
- ct_rwlock_rdlock(&ct->resources_lock);
-
struct conn *rev_conn = conn_lookup(ct, &nc->key, now);
- struct nat_conn_key_node *nat_conn_key_node =
- nat_conn_keys_lookup(&ct->nat_conn_keys, &nc->key, ct->hash_basis);
- if (nat_conn_key_node
- && !memcmp(&nat_conn_key_node->value, &nc->rev_key,
- sizeof nat_conn_key_node->value)
- && !rev_conn) {
+ if (alg_un_nat) {
hmap_insert(&ct->buckets[un_nat_conn_bucket].connections,
&nc->node, un_nat_hash);
} else {
- free(nc);
+ ct_rwlock_rdlock(&ct->resources_lock);
+
+ struct nat_conn_key_node *nat_conn_key_node =
+ nat_conn_keys_lookup(&ct->nat_conn_keys, &nc->key, ct->hash_basis);
+ if (nat_conn_key_node && !memcmp(&nat_conn_key_node->value,
+ &nc->rev_key, sizeof nat_conn_key_node->value) && !rev_conn) {
+
+ hmap_insert(&ct->buckets[un_nat_conn_bucket].connections,
+ &nc->node, un_nat_hash);
+ } else {
+ free(nc);
+ }
+ ct_rwlock_unlock(&ct->resources_lock);
}
- ct_rwlock_unlock(&ct->resources_lock);
ct_lock_unlock(&ct->buckets[un_nat_conn_bucket].lock);
}
@@ -662,6 +856,7 @@ handle_nat(struct dp_packet *pkt, struct conn *conn,
(!(pkt->md.ct_state & (CS_SRC_NAT | CS_DST_NAT)) ||
(pkt->md.ct_state & (CS_SRC_NAT | CS_DST_NAT) &&
zone != pkt->md.ct_zone))) {
+
if (pkt->md.ct_state & (CS_SRC_NAT | CS_DST_NAT)) {
pkt->md.ct_state &= ~(CS_SRC_NAT | CS_DST_NAT);
}
@@ -738,12 +933,19 @@ check_orig_tuple(struct conntrack *ct, struct dp_packet *pkt,
return *conn ? true : false;
}
+static bool
+is_un_nat_conn_valid(const struct conn *un_nat_conn)
+{
+ return un_nat_conn->conn_type == CT_CONN_TYPE_UN_NAT;
+}
+
static void
process_one(struct conntrack *ct, struct dp_packet *pkt,
struct conn_lookup_ctx *ctx, uint16_t zone,
bool force, bool commit, long long now, const uint32_t *setmark,
const struct ovs_key_ct_labels *setlabel,
- const struct nat_action_info_t *nat_action_info)
+ const struct nat_action_info_t *nat_action_info,
+ const char *helper)
{
struct conn *conn;
unsigned bucket = hash_to_bucket(ctx->hash);
@@ -789,28 +991,64 @@ process_one(struct conntrack *ct, struct dp_packet *pkt,
bool create_new_conn = false;
struct conn conn_for_un_nat_copy;
conn_for_un_nat_copy.conn_type = CT_CONN_TYPE_DEFAULT;
+ bool ftp_ctl = is_ftp_ctl(pkt);
+
if (OVS_LIKELY(conn)) {
- create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now, bucket);
+ if (ftp_ctl) {
+ /* Keep sequence tracking in sync with the source of the
+ * sequence skew. */
+ if (ctx->reply != conn->seq_skew_dir) {
+ handle_ftp_ctl(ct, ctx, pkt, conn, now, CT_FTP_CTL_OTHER,
+ !!nat_action_info);
+ create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now,
+ bucket);
+ } else {
+ create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now,
+ bucket);
+ handle_ftp_ctl(ct, ctx, pkt, conn, now, CT_FTP_CTL_OTHER,
+ !!nat_action_info);
+ }
+ } else {
+ create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now,
+ bucket);
+ }
if (nat_action_info && !create_new_conn) {
handle_nat(pkt, conn, zone, ctx->reply, ctx->icmp_related);
}
- } else if (check_orig_tuple(ct, pkt, ctx, now, &bucket, &conn,
- nat_action_info)) {
- create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now, bucket);
+
+ }else if (check_orig_tuple(ct, pkt, ctx, now, &bucket, &conn,
+ nat_action_info)) {
+ create_new_conn = conn_update_state(ct, pkt, ctx, &conn, now,
+ bucket);
} else {
if (ctx->icmp_related) {
+ /* An icmp related conn should always be found; no new
+ connection is created based on an icmp related packet. */
pkt->md.ct_state = CS_INVALID;
} else {
create_new_conn = true;
}
}
+ const struct alg_exp_node *alg_exp = NULL;
if (OVS_UNLIKELY(create_new_conn)) {
+ struct alg_exp_node alg_exp_entry;
+
+ ct_rwlock_rdlock(&ct->resources_lock);
+ alg_exp = expectation_lookup(&ct->alg_expectations, &ctx->key,
+ ct->hash_basis);
+ if (alg_exp) {
+ alg_exp_entry = *alg_exp;
+ alg_exp = &alg_exp_entry;
+ }
+ ct_rwlock_unlock(&ct->resources_lock);
+
conn = conn_not_found(ct, pkt, ctx, commit, now, nat_action_info,
- &conn_for_un_nat_copy);
+ &conn_for_un_nat_copy, helper, alg_exp);
}
- write_ct_md(pkt, zone, conn, &ctx->key);
+ write_ct_md(pkt, zone, conn, &ctx->key, alg_exp);
+
if (conn && setmark) {
set_mark(pkt, conn, setmark[0], setmark[1]);
}
@@ -819,10 +1057,21 @@ process_one(struct conntrack *ct, struct dp_packet *pkt,
set_label(pkt, conn, &setlabel[0], &setlabel[1]);
}
+ struct conn conn_for_expectation;
+ if (conn && ftp_ctl) {
+ conn_for_expectation = *conn;
+ }
+
ct_lock_unlock(&ct->buckets[bucket].lock);
- if (conn_for_un_nat_copy.conn_type == CT_CONN_TYPE_UN_NAT) {
- create_un_nat_conn(ct, &conn_for_un_nat_copy, now);
+ if (is_un_nat_conn_valid(&conn_for_un_nat_copy)) {
+ create_un_nat_conn(ct, &conn_for_un_nat_copy, now, !!alg_exp);
+ }
+
+ /* FTP control packet handling with expectation creation. */
+ if (OVS_UNLIKELY(conn && ftp_ctl)) {
+ handle_ftp_ctl(ct, ctx, pkt, &conn_for_expectation,
+ now, CT_FTP_CTL_INTEREST, !!nat_action_info);
}
}
@@ -842,26 +1091,20 @@ conntrack_execute(struct conntrack *ct, struct dp_packet_batch *pkt_batch,
const char *helper,
const struct nat_action_info_t *nat_action_info)
{
+
struct dp_packet **pkts = pkt_batch->packets;
size_t cnt = pkt_batch->count;
- long long now = time_msec();
struct conn_lookup_ctx ctx;
-
- if (helper) {
- static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
-
- VLOG_WARN_RL(&rl, "ALG helper \"%s\" not supported", helper);
- /* Continue without the helper */
- }
+ long long now = time_msec();
for (size_t i = 0; i < cnt; i++) {
if (!conn_key_extract(ct, pkts[i], dl_type, &ctx, zone)) {
pkts[i]->md.ct_state = CS_INVALID;
- write_ct_md(pkts[i], zone, NULL, NULL);
+ write_ct_md(pkts[i], zone, NULL, NULL, NULL);
continue;
}
process_one(ct, pkts[i], &ctx, zone, force, commit,
- now, setmark, setlabel, nat_action_info);
+ now, setmark, setlabel, nat_action_info, helper);
}
return 0;
@@ -870,8 +1113,12 @@ conntrack_execute(struct conntrack *ct, struct dp_packet_batch *pkt_batch,
static void
set_mark(struct dp_packet *pkt, struct conn *conn, uint32_t val, uint32_t mask)
{
- pkt->md.ct_mark = val | (pkt->md.ct_mark & ~(mask));
- conn->mark = pkt->md.ct_mark;
+ if (conn->alg_related) {
+ pkt->md.ct_mark = conn->mark;
+ } else {
+ pkt->md.ct_mark = val | (pkt->md.ct_mark & ~(mask));
+ conn->mark = pkt->md.ct_mark;
+ }
}
static void
@@ -879,16 +1126,20 @@ set_label(struct dp_packet *pkt, struct conn *conn,
const struct ovs_key_ct_labels *val,
const struct ovs_key_ct_labels *mask)
{
- ovs_u128 v, m;
+ if (conn->alg_related) {
+ pkt->md.ct_label = conn->label;
+ } else {
+ ovs_u128 v, m;
- memcpy(&v, val, sizeof v);
- memcpy(&m, mask, sizeof m);
+ memcpy(&v, val, sizeof v);
+ memcpy(&m, mask, sizeof m);
- pkt->md.ct_label.u64.lo = v.u64.lo
+ pkt->md.ct_label.u64.lo = v.u64.lo
| (pkt->md.ct_label.u64.lo & ~(m.u64.lo));
- pkt->md.ct_label.u64.hi = v.u64.hi
+ pkt->md.ct_label.u64.hi = v.u64.hi
| (pkt->md.ct_label.u64.hi & ~(m.u64.hi));
- conn->label = pkt->md.ct_label;
+ conn->label = pkt->md.ct_label;
+ }
}
?
@@ -897,8 +1148,8 @@ set_label(struct dp_packet *pkt, struct conn *conn,
* LLONG_MAX if 'ctb' is empty. The return value might be smaller than 'now',
* if 'limit' is reached */
static long long
-sweep_bucket(struct conntrack *ct, struct conntrack_bucket *ctb, long long now,
- size_t limit)
+sweep_bucket(struct conntrack *ct, struct conntrack_bucket *ctb,
+ long long now, size_t limit)
OVS_REQUIRES(ctb->lock)
{
struct conn *conn, *next;
@@ -924,6 +1175,28 @@ sweep_bucket(struct conntrack *ct, struct conntrack_bucket *ctb, long long now,
}
}
+#define MAX_ALG_EXP_TO_EXPIRE 1000
+ size_t alg_exp_count = hmap_count(&ct->alg_expectations);
+ /* XXX: revisit this. */
+ size_t max_to_expire =
+ MAX(alg_exp_count/10, MAX_ALG_EXP_TO_EXPIRE);
+ count = 0;
+ ct_rwlock_wrlock(&ct->resources_lock);
+ struct alg_exp_node *alg_exp_node, *alg_exp_node_next;
+ LIST_FOR_EACH_SAFE (alg_exp_node, alg_exp_node_next,
+ exp_node, &ct->alg_exp_list) {
+ if (now < alg_exp_node->expiration ||
+ count >= max_to_expire) {
+ min_expiration = MIN(min_expiration, alg_exp_node->expiration);
+ break;
+ }
+ ovs_list_remove(&alg_exp_node->exp_node);
+ hmap_remove(&ct->alg_expectations, &alg_exp_node->node);
+ free(alg_exp_node);
+ count++;
+ }
+ ct_rwlock_unlock(&ct->resources_lock);
+
return min_expiration;
}
@@ -1712,7 +1985,6 @@ nat_select_range_tuple(struct conntrack *ct, const struct conn *conn,
bool all_ports_tried = false;
bool original_ports_tried = false;
struct ct_addr first_addr = ct_addr;
- *nat_conn = *conn;
while (true) {
if (conn->nat_info->nat_action & NAT_ACTION_SRC) {
@@ -1805,7 +2077,8 @@ nat_conn_keys_lookup(struct hmap *nat_conn_keys,
/* This function must be called with the ct->resources write lock taken. */
static void
-nat_conn_keys_remove(struct hmap *nat_conn_keys, const struct conn_key *key,
+nat_conn_keys_remove(struct hmap *nat_conn_keys,
+ const struct conn_key *key,
uint32_t basis)
{
struct nat_conn_key_node *nat_conn_key_node;
@@ -1890,6 +2163,7 @@ static void
delete_conn(struct conn *conn)
{
free(conn->nat_info);
+ free(conn->alg);
free(conn);
}
?
@@ -1954,6 +2228,11 @@ conn_to_ct_dpif_entry(const struct conn *conn, struct ct_dpif_entry *entry,
if (class->conn_get_protoinfo) {
class->conn_get_protoinfo(conn, &entry->protoinfo);
}
+
+ if (conn->alg) {
+ /* Caller is responsible for freeing. */
+ entry->helper.name = xstrdup(conn->alg);
+ }
}
int
@@ -2024,7 +2303,7 @@ conntrack_flush(struct conntrack *ct, const uint16_t *zone)
struct conn *conn, *next;
ct_lock_lock(&ct->buckets[i].lock);
- HMAP_FOR_EACH_SAFE(conn, next, node, &ct->buckets[i].connections) {
+ HMAP_FOR_EACH_SAFE (conn, next, node, &ct->buckets[i].connections) {
if ((!zone || *zone == conn->key.zone) &&
(conn->conn_type == CT_CONN_TYPE_DEFAULT)) {
conn_clean(ct, conn, &ct->buckets[i]);
@@ -2032,5 +2311,635 @@ conntrack_flush(struct conntrack *ct, const uint16_t *zone)
}
ct_lock_unlock(&ct->buckets[i].lock);
}
+
+ ct_rwlock_wrlock(&ct->resources_lock);
+ struct alg_exp_node *alg_exp_node, *alg_exp_node_next;
+ HMAP_FOR_EACH_SAFE (alg_exp_node, alg_exp_node_next,
+ node, &ct->alg_expectations) {
+ if (!zone || *zone == alg_exp_node->key.zone) {
+ ovs_list_remove(&alg_exp_node->exp_node);
+ hmap_remove(&ct->alg_expectations, &alg_exp_node->node);
+ free(alg_exp_node);
+ }
+ }
+ ct_rwlock_unlock(&ct->resources_lock);
return 0;
}
+
+/* This function must be called with the ct->resources read lock taken. */
+static struct alg_exp_node *
+expectation_lookup(struct hmap *alg_expectations,
+ const struct conn_key *key, uint32_t basis)
+{
+
+ struct conn_key check_key = *key;
+ check_key.src.port = ALG_WC_SRC_PORT;
+ struct alg_exp_node *alg_exp_node;
+
+ uint32_t alg_exp_conn_key_hash = conn_key_hash(&check_key, basis);
+ HMAP_FOR_EACH_WITH_HASH (alg_exp_node, node,
+ alg_exp_conn_key_hash,
+ alg_expectations) {
+ if (!memcmp(&alg_exp_node->key, &check_key,
+ sizeof alg_exp_node->key)) {
+ return alg_exp_node;
+ }
+ }
+ return NULL;
+}
+
+static void
+expectation_create(struct conntrack *ct,
+ ovs_be16 dst_port,
+ const long long now,
+ enum ct_alg_mode mode,
+ const struct conn *master_conn)
+{
+ struct ct_addr src_addr;
+ struct ct_addr dst_addr;
+ struct ct_addr alg_nat_repl_addr;
+
+ switch (mode) {
+ case CT_FTP_MODE_ACTIVE:
+ src_addr = master_conn->rev_key.src.addr;
+ dst_addr = master_conn->rev_key.dst.addr;
+ alg_nat_repl_addr = master_conn->key.src.addr;
+ break;
+ case CT_FTP_MODE_PASSIVE:
+ src_addr = master_conn->key.src.addr;
+ dst_addr = master_conn->key.dst.addr;
+ alg_nat_repl_addr = master_conn->rev_key.dst.addr;
+ break;
+ default:
+ OVS_NOT_REACHED();
+ }
+
+ struct alg_exp_node *alg_exp_node =
+ xzalloc(sizeof *alg_exp_node);
+ alg_exp_node->key.dl_type = master_conn->key.dl_type;
+ alg_exp_node->key.nw_proto = master_conn->key.nw_proto;
+ alg_exp_node->key.zone = master_conn->key.zone;
+ alg_exp_node->key.src.addr = src_addr;
+ alg_exp_node->key.dst.addr = dst_addr;
+ alg_exp_node->key.src.port = ALG_WC_SRC_PORT;
+ alg_exp_node->key.dst.port = dst_port;
+ alg_exp_node->master_mark = master_conn->mark;
+ alg_exp_node->master_label = master_conn->label;
+ alg_exp_node->master_key = master_conn->key;
+ alg_exp_node->passive_mode = mode == CT_FTP_MODE_PASSIVE ? true : false;
+ /* Take the write lock here because it is almost 100%
+ * likely that the lookup will fail and
+ * expectation_create() will be called below. */
+ ct_rwlock_wrlock(&ct->resources_lock);
+ struct alg_exp_node *alg_exp = expectation_lookup(
+ &ct->alg_expectations, &alg_exp_node->key, ct->hash_basis);
+ if (alg_exp) {
+ free(alg_exp_node);
+ ct_rwlock_unlock(&ct->resources_lock);
+ return;
+ }
+
+ alg_exp_node->alg_nat_repl_addr = alg_nat_repl_addr;
+ uint32_t alg_exp_conn_key_hash =
+ conn_key_hash(&alg_exp_node->key,
+ ct->hash_basis);
+ hmap_insert(&ct->alg_expectations,
+ &alg_exp_node->node,
+ alg_exp_conn_key_hash);
+
+ alg_exp_init_expiration(ct, alg_exp_node, now);
+ ct_rwlock_unlock(&ct->resources_lock);
+}
+
+static uint8_t
+get_v4_byte_be(ovs_be32 v4_addr, uint8_t index)
+{
+ uint8_t *byte_ptr = (OVS_FORCE uint8_t *) &v4_addr;
+ return byte_ptr[index];
+}
+
+static void
+replace_substring(char *substr, uint8_t substr_size,
+ uint8_t total_size, char *rep_str,
+ uint8_t rep_str_size)
+{
+ memmove(substr + rep_str_size, substr + substr_size,
+ total_size - substr_size);
+ memcpy(substr, rep_str, rep_str_size);
+}
+
+/* Replace IPV4 address in FTP message with NATed address. */
+static int
+repl_ftp_v4_addr(struct dp_packet *pkt, ovs_be32 v4_addr_rep,
+ char *ftp_data_start,
+ size_t addr_offset_from_ftp_data_start)
+{
+#define MAX_FTP_V4_NAT_DELTA 8
+
+ /* Do conservative check for pathological MTU usage. */
+ uint32_t orig_used_size = dp_packet_size(pkt);
+ uint16_t allocated_size = dp_packet_get_allocated(pkt);
+ if (orig_used_size + MAX_FTP_V4_NAT_DELTA > allocated_size) {
+ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
+ VLOG_WARN_RL(&rl, "Unsupported effective MTU %u used with FTP",
+ allocated_size);
+ return 0;
+ }
+
+ size_t remain_size = tcp_payload_length(pkt) -
+ addr_offset_from_ftp_data_start;
+
+ int overall_delta = 0;
+ char *byte_str = ftp_data_start + addr_offset_from_ftp_data_start;
+ char *next_delim;
+ size_t substr_size;
+ uint8_t rep_byte;
+ char rep_str[4];
+ size_t replace_size;
+
+ for (uint8_t i = 0; i < 4; i++) {
+ memset(rep_str, 0 , sizeof rep_str);
+ next_delim = memchr(byte_str,',',4);
+ ovs_assert(next_delim);
+ substr_size = next_delim - byte_str;
+ remain_size -= substr_size;
+ rep_byte = get_v4_byte_be(v4_addr_rep, i);
+ replace_size = sprintf(rep_str, "%d", rep_byte);
+ ovs_assert(replace_size == strlen(rep_str));
+ replace_substring(byte_str, substr_size, remain_size,
+ rep_str, replace_size);
+
+ overall_delta += (int) replace_size - (int) substr_size;
+ /* Add 1 to skip the ',' character. */
+ byte_str += replace_size + 1;
+ }
+
+ dp_packet_set_size(pkt, orig_used_size + overall_delta);
+ return overall_delta;
+}
+
+static char *
+skip_non_digits(char *str)
+{
+ while ((!isdigit(*str)) && (*str != 0)) {
+ str++;
+ }
+ return str;
+}
+
+static char *
+terminate_number_str(char *str, uint8_t max_digits)
+{
+ uint8_t digits_found = 0;
+ while (isdigit(*str) && digits_found <= max_digits) {
+ str++;
+ digits_found++;
+ }
+
+ *str = 0;
+ return str;
+}
+
+
+static void
+get_ftp_ctl_msg(struct dp_packet *pkt, char *ftp_msg)
+{
+ struct tcp_header *th = dp_packet_l4(pkt);
+ char *tcp_hdr = (char *) th;
+ uint32_t tcp_payload_len = tcp_payload_length(pkt);
+ size_t tcp_payload_of_interest = MIN(tcp_payload_len,
+ LARGEST_FTP_MSG_OF_INTEREST);
+ size_t tcp_hdr_len = TCP_OFFSET(th->tcp_ctl) * 4;
+
+ ovs_strlcpy(ftp_msg, tcp_hdr + tcp_hdr_len,
+ tcp_payload_of_interest);
+}
+
+static enum ftp_ctl_pkt
+detect_ftp_ctl_type(const struct conn_lookup_ctx *ctx,
+ struct dp_packet *pkt)
+{
+
+ char ftp_msg[LARGEST_FTP_MSG_OF_INTEREST + 1] = {0};
+ get_ftp_ctl_msg(pkt, ftp_msg);
+ if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) {
+ if (strncasecmp(ftp_msg, FTP_EPRT_CMD, strlen(FTP_EPRT_CMD)) &&
+ !strcasestr(ftp_msg, FTP_EPSV_REPLY)) {
+ return CT_FTP_CTL_OTHER;
+ }
+ } else {
+ if (strncasecmp(ftp_msg, FTP_PORT_CMD, strlen(FTP_PORT_CMD)) &&
+ strncasecmp(ftp_msg, FTP_PASV_REPLY_CODE,
+ strlen(FTP_PASV_REPLY_CODE))) {
+ return CT_FTP_CTL_OTHER;
+ }
+ }
+
+ return CT_FTP_CTL_INTEREST;
+}
+
+static enum ftp_ctl_pkt
+process_ftp_ctl_v4(struct conntrack *ct,
+ struct dp_packet *pkt,
+ const struct conn *conn_for_expectation,
+ long long now, ovs_be32 *v4_addr_rep,
+ char **ftp_data_v4_start,
+ size_t *addr_offset_from_ftp_data_start)
+{
+ struct tcp_header *th = dp_packet_l4(pkt);
+ size_t tcp_hdr_len = TCP_OFFSET(th->tcp_ctl) * 4;
+ char *tcp_hdr = (char *) th;
+ *ftp_data_v4_start = tcp_hdr + tcp_hdr_len;
+ char ftp_msg[LARGEST_FTP_MSG_OF_INTEREST + 1] = {0};
+ get_ftp_ctl_msg(pkt, ftp_msg);
+
+ char *ftp = ftp_msg;
+ enum ct_alg_mode mode;
+ if (!strncasecmp(ftp_msg, FTP_PORT_CMD, strlen(FTP_PORT_CMD))) {
+ ftp = ftp_msg + strlen(FTP_PORT_CMD);
+ mode = CT_FTP_MODE_ACTIVE;
+ } else {
+ ftp = ftp_msg + strlen(FTP_PASV_REPLY_CODE);
+ mode = CT_FTP_MODE_PASSIVE;
+ }
+
+ /* Find first space. */
+ ftp = strchr(ftp, ' ');
+ if (!ftp) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ /* Find the first digit, after space. */
+ ftp = skip_non_digits(ftp);
+ if (*ftp == 0) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ char *ip_addr_start = ftp;
+ *addr_offset_from_ftp_data_start = ip_addr_start - ftp_msg;
+ uint8_t comma_count = 0;
+
+ while ((comma_count < 4) && (*ftp != 0)) {
+ if (*ftp == ',') {
+ comma_count ++;
+ if (comma_count == 4) {
+ *ftp = 0;
+ } else {
+ *ftp = '.';
+ }
+ }
+ ftp++;
+ }
+ if (comma_count != 4) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ struct in_addr ip_addr;
+ int rc2 = inet_pton(AF_INET, ip_addr_start, &ip_addr);
+ if (rc2 != 1) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ char *save_ftp = ftp;
+ ftp = terminate_number_str(ftp, MAX_FTP_PORT_DGTS);
+ if (!ftp) {
+ return CT_FTP_CTL_INVALID;
+ }
+ int value;
+ if (!str_to_int(save_ftp, 10, &value)) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ /* This is derived from the L4 port maximum is 65535. */
+ if (value > 255) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ uint16_t port_hs = value;
+ port_hs <<= 8;
+
+ /* Skip over comma. */
+ ftp++;
+ save_ftp = ftp;
+ bool digit_found = false;
+ while (isdigit(*ftp)) {
+ ftp++;
+ digit_found = true;
+ }
+ if (!digit_found) {
+ return CT_FTP_CTL_INVALID;
+ }
+ *ftp = 0;
+ if (!str_to_int(save_ftp, 10, &value)) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ if (value > 255) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ uint16_t port_lo_hs = value;
+ if (65535 - port_hs < port_lo_hs) {
+ return CT_FTP_CTL_INVALID;
+ }
+ port_hs |= port_lo_hs;
+ ovs_be16 port = htons(port_hs);
+ ovs_be32 conn_ipv4_addr;
+
+ switch (mode) {
+ case CT_FTP_MODE_ACTIVE:
+ *v4_addr_rep = conn_for_expectation->rev_key.dst.addr.ipv4_aligned;
+ conn_ipv4_addr = conn_for_expectation->key.src.addr.ipv4_aligned;
+ break;
+ case CT_FTP_MODE_PASSIVE:
+ *v4_addr_rep = conn_for_expectation->key.dst.addr.ipv4_aligned;
+ conn_ipv4_addr = conn_for_expectation->rev_key.src.addr.ipv4_aligned;
+ break;
+ default:
+ OVS_NOT_REACHED();
+ }
+
+ ovs_be32 ftp_ipv4_addr;
+ ftp_ipv4_addr = ip_addr.s_addr;
+ /* Although most servers will block this exploit, there may be some
+ * less well managed. */
+ if ((ftp_ipv4_addr != conn_ipv4_addr) &&
+ (ftp_ipv4_addr != *v4_addr_rep)) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ expectation_create(ct, port, now, mode, conn_for_expectation);
+ return CT_FTP_CTL_INTEREST;
+}
+
+static char *
+skip_ipv6_digits(char *str)
+{
+ while (isxdigit(*str) || (*str == ':') || (*str == '.')) {
+ str++;
+ }
+ return str;
+}
+
+static enum ftp_ctl_pkt
+process_ftp_ctl_v6(struct conntrack *ct,
+ struct dp_packet *pkt,
+ const struct conn *conn_for_expectation,
+ long long now,
+ struct ct_addr *v6_addr_rep,
+ char **ftp_data_start,
+ size_t *addr_offset_from_ftp_data_start,
+ size_t *addr_size, enum ct_alg_mode *mode)
+{
+ struct tcp_header *th = dp_packet_l4(pkt);
+ size_t tcp_hdr_len = TCP_OFFSET(th->tcp_ctl) * 4;
+ char *tcp_hdr = (char *) th;
+ char ftp_msg[LARGEST_FTP_MSG_OF_INTEREST + 1] = {0};
+
+ get_ftp_ctl_msg(pkt, ftp_msg);
+ *ftp_data_start = tcp_hdr + tcp_hdr_len;
+
+ char *ftp = ftp_msg;
+ struct in6_addr ip6_addr;
+ if (!strncasecmp(ftp_msg, FTP_EPRT_CMD, strlen(FTP_EPRT_CMD))) {
+ ftp = ftp_msg + strlen(FTP_EPRT_CMD);
+ ftp = skip_non_digits(ftp);
+ if ((*ftp != FTP_AF_V6) || isdigit(*(ftp + 1))) {
+ return CT_FTP_CTL_INVALID;
+ }
+ /* Jump over delimiter. */
+ ftp += 2;
+
+ char *ip_addr_start = ftp;
+ memset(&ip6_addr, 0, sizeof ip6_addr);
+ *addr_offset_from_ftp_data_start = ip_addr_start - ftp_msg;
+ ftp = skip_ipv6_digits(ftp);
+ *ftp = 0;
+ *addr_size = ftp - ip_addr_start;
+ int rc2 = inet_pton(AF_INET6, ip_addr_start, &ip6_addr);
+ if (rc2 != 1) {
+ return CT_FTP_CTL_INVALID;
+ }
+ ftp++;
+ *mode = CT_FTP_MODE_ACTIVE;
+ } else {
+ ftp = ftp_msg + strcspn(ftp_msg, "(");
+ ftp = skip_non_digits(ftp);
+ if (!isdigit(*ftp)) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ /* Not used for passive mode. */
+ *addr_offset_from_ftp_data_start = 0;
+ *addr_size = 0;
+
+ *mode = CT_FTP_MODE_PASSIVE;
+ }
+
+ char *save_ftp = ftp;
+ ftp = terminate_number_str(ftp , MAX_EXT_FTP_PORT_DGTS);
+ if (!ftp) {
+ return CT_FTP_CTL_INVALID;
+ }
+ int value;
+ if (!str_to_int(save_ftp, 10, &value)) {
+ return CT_FTP_CTL_INVALID;
+ }
+ if (value > CT_MAX_L4_PORT) {
+ return CT_FTP_CTL_INVALID;
+ }
+
+ uint16_t port_hs = value;
+ ovs_be16 port = htons(port_hs);
+
+ switch (*mode) {
+ case CT_FTP_MODE_ACTIVE:
+ *v6_addr_rep = conn_for_expectation->rev_key.dst.addr;
+ /* Although most servers will block this exploit, there may be some
+ * less well managed. */
+ if (memcmp(&ip6_addr, &v6_addr_rep->ipv6_aligned, sizeof ip6_addr) &&
+ memcmp(&ip6_addr, &conn_for_expectation->key.src.addr.ipv6_aligned,
+ sizeof ip6_addr)) {
+ return CT_FTP_CTL_INVALID;
+ }
+ break;
+ case CT_FTP_MODE_PASSIVE:
+ *v6_addr_rep = conn_for_expectation->key.dst.addr;
+ break;
+ default:
+ OVS_NOT_REACHED();
+ }
+
+ expectation_create(ct, port, now, *mode, conn_for_expectation);
+ return CT_FTP_CTL_INTEREST;
+}
+
+static int
+repl_ftp_v6_addr(struct dp_packet *pkt, struct ct_addr v6_addr_rep,
+ char *ftp_data_start,
+ size_t addr_offset_from_ftp_data_start,
+ size_t addr_size, enum ct_alg_mode mode)
+{
+/* This is slightly bigger than really possible. */
+#define MAX_FTP_V6_NAT_DELTA 45
+
+ if (mode == CT_FTP_MODE_PASSIVE) {
+ return 0;
+ }
+
+ /* Do conservative check for pathological MTU usage. */
+ uint32_t orig_used_size = dp_packet_size(pkt);
+ uint16_t allocated_size = dp_packet_get_allocated(pkt);
+ if (orig_used_size + MAX_FTP_V6_NAT_DELTA > allocated_size) {
+ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
+ VLOG_WARN_RL(&rl, "Unsupported effective MTU %u used with FTP",
+ allocated_size);
+ return 0;
+ }
+
+ const char *rc;
+ char v6_addr_str[IPV6_SCAN_LEN] = {0};
+ rc = inet_ntop(AF_INET6, &v6_addr_rep.ipv6_aligned, v6_addr_str,
+ IPV6_SCAN_LEN - 1);
+ ovs_assert(rc != NULL);
+
+ size_t replace_addr_size = strlen(v6_addr_str);
+
+ size_t remain_size = tcp_payload_length(pkt) -
+ addr_offset_from_ftp_data_start;
+
+ char *pkt_addr_str = ftp_data_start + addr_offset_from_ftp_data_start;
+ replace_substring(pkt_addr_str, addr_size, remain_size,
+ v6_addr_str, replace_addr_size);
+
+ int overall_delta = (int) replace_addr_size - (int) addr_size;
+
+ dp_packet_set_size(pkt, orig_used_size + overall_delta);
+ return overall_delta;
+}
+
+static void
+handle_ftp_ctl(struct conntrack *ct, const struct conn_lookup_ctx *ctx,
+ struct dp_packet *pkt,
+ const struct conn *conn_for_expectation,
+ long long now, enum ftp_ctl_pkt ftp_ctl, bool nat)
+{
+ struct ip_header *l3_hdr = dp_packet_l3(pkt);
+ ovs_be32 v4_addr_rep = 0;
+ struct ct_addr v6_addr_rep;
+ size_t addr_offset_from_ftp_data_start;
+ size_t addr_size = 0;
+ char *ftp_data_start;
+ bool do_seq_skew_adj = true;
+ enum ct_alg_mode mode = CT_FTP_MODE_ACTIVE;
+
+ if (detect_ftp_ctl_type(ctx, pkt) != ftp_ctl) {
+ return;
+ }
+
+ if (!nat || !conn_for_expectation->seq_skew) {
+ do_seq_skew_adj = false;
+ }
+
+ struct ovs_16aligned_ip6_hdr *nh6 = dp_packet_l3(pkt);
+ int64_t seq_skew = 0;
+ bool seq_skew_dir;
+ if (ftp_ctl == CT_FTP_CTL_OTHER) {
+ seq_skew = conn_for_expectation->seq_skew;
+ seq_skew_dir = conn_for_expectation->seq_skew_dir;
+ } else if (ftp_ctl == CT_FTP_CTL_INTEREST) {
+ enum ftp_ctl_pkt rc;
+ if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) {
+ rc = process_ftp_ctl_v6(ct, pkt, conn_for_expectation,
+ now, &v6_addr_rep, &ftp_data_start,
+ &addr_offset_from_ftp_data_start,
+ &addr_size, &mode);
+ } else {
+ rc = process_ftp_ctl_v4(ct, pkt, conn_for_expectation,
+ now, &v4_addr_rep, &ftp_data_start,
+ &addr_offset_from_ftp_data_start);
+ }
+ if (rc == CT_FTP_CTL_INVALID) {
+ static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 5);
+ VLOG_WARN_RL(&rl, "Invalid FTP control packet format");
+ pkt->md.ct_state |= CS_TRACKED | CS_INVALID;
+ return;
+ } else if (rc == CT_FTP_CTL_INTEREST) {
+ uint16_t ip_len;
+ if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) {
+ seq_skew = repl_ftp_v6_addr(pkt, v6_addr_rep, ftp_data_start,
+ addr_offset_from_ftp_data_start,
+ addr_size, mode);
+ seq_skew_dir = ctx->reply;
+ if (seq_skew) {
+ ip_len = ntohs(nh6->ip6_ctlun.ip6_un1.ip6_un1_plen);
+ ip_len += seq_skew;
+ nh6->ip6_ctlun.ip6_un1.ip6_un1_plen = htons(ip_len);
+ conn_seq_skew_set(ct, &conn_for_expectation->key, now,
+ seq_skew, seq_skew_dir);
+ }
+ } else {
+ seq_skew = repl_ftp_v4_addr(pkt, v4_addr_rep, ftp_data_start,
+ addr_offset_from_ftp_data_start);
+ seq_skew_dir = ctx->reply;
+ ip_len = ntohs(l3_hdr->ip_tot_len);
+ if (seq_skew) {
+ ip_len += seq_skew;
+ l3_hdr->ip_csum = recalc_csum16(l3_hdr->ip_csum,
+ l3_hdr->ip_tot_len, htons(ip_len));
+ l3_hdr->ip_tot_len = htons(ip_len);
+ conn_seq_skew_set(ct, &conn_for_expectation->key, now,
+ seq_skew, seq_skew_dir);
+ }
+ }
+ } else {
+ OVS_NOT_REACHED();
+ }
+ } else {
+ OVS_NOT_REACHED();
+ }
+
+ struct tcp_header *th = dp_packet_l4(pkt);
+ if (do_seq_skew_adj && seq_skew != 0) {
+ if (ctx->reply != conn_for_expectation->seq_skew_dir) {
+
+ uint32_t tcp_ack = ntohl(get_16aligned_be32(&th->tcp_ack));
+
+ if ((seq_skew > 0) && (tcp_ack < seq_skew)) {
+ /* Should not be possible; will be marked invalid. */
+ tcp_ack = 0;
+ } else if ((seq_skew < 0) && (UINT32_MAX - tcp_ack < -seq_skew)) {
+ tcp_ack = (-seq_skew) - (UINT32_MAX - tcp_ack);
+ } else {
+ tcp_ack -= 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 ((seq_skew > 0) && (UINT32_MAX - tcp_seq < seq_skew)) {
+ tcp_seq = seq_skew - (UINT32_MAX - tcp_seq);
+ } else if ((seq_skew < 0) && (tcp_seq < -seq_skew)) {
+ /* Should not be possible; will be marked invalid. */
+ tcp_seq = 0;
+ } else {
+ tcp_seq += seq_skew;
+ }
+ ovs_be32 new_tcp_seq = htonl(tcp_seq);
+ put_16aligned_be32(&th->tcp_seq, new_tcp_seq);
+ }
+ }
+
+ const char *tail = dp_packet_tail(pkt);
+ uint8_t pad = dp_packet_l2_pad_size(pkt);
+ th->tcp_csum = 0;
+ uint32_t tcp_csum;
+ if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) {
+ tcp_csum = packet_csum_pseudoheader6(nh6);
+ } else {
+ tcp_csum = packet_csum_pseudoheader(l3_hdr);
+ }
+ th->tcp_csum = csum_finish(
+ csum_continue(tcp_csum, th, tail - (char *) th - pad));
+ return;
+}
diff --git a/lib/conntrack.h b/lib/conntrack.h
index defde4c..4e77ff4 100644
--- a/lib/conntrack.h
+++ b/lib/conntrack.h
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2015, 2016 Nicira, Inc.
+ * Copyright (c) 2015, 2016, 2017 Nicira, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -267,9 +267,17 @@ struct conntrack {
/* The following resources are referenced during nat connection
* creation and deletion. */
struct hmap nat_conn_keys OVS_GUARDED;
+ /* Hash table for alg expectations. Expectations are created
+ * by control connections to help create data connections. */
+ struct hmap alg_expectations OVS_GUARDED;
+ /* Expiry list for alg expectations. */
+ struct ovs_list alg_exp_list OVS_GUARDED;
/* This lock is used during NAT connection creation and deletion;
* it is taken after a bucket lock and given back before that
* bucket unlock.
+ * This lock is similarly used to guard alg_expectations and
+ * alg_exp_list. If a bucket lock is also held during the normal
+ * code flow, then is must be taken first first and released last.
*/
struct ct_rwlock resources_lock;
--
1.9.1
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