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conntrack: Exclude l2 padding in 'conn_key_extract()'.
'conn_key_extract()' in userspace conntrack is including L2
(Ethernet) pad bytes for both L3 and L4 sizes. One problem is
any packet with non-zero L2 padding can incorrectly fail L4
checksum validation.

This patch fixes conn_key_extract() by ignoring L2 pad bytes.

Fixes: a489b16 ("conntrack: New userspace connection tracker.")
CC: Daniele Di Proietto <diproiettod@ovn.org>
Co-authored-by: Vishal Deep Ajmera <vishal.deep.ajmera@ericsson.com>
Co-authored-by: Venkatesan Pradeep <venkatesan.pradeep@ericsson.com>
Co-authored-by: Nitin Katiyar <nitin.katiyar@ericsson.com>
Signed-off-by: Vishal Deep Ajmera <vishal.deep.ajmera@ericsson.com>
Signed-off-by: Venkatesan Pradeep <venkatesan.pradeep@ericsson.com>
Signed-off-by: Nitin Katiyar <nitin.katiyar@ericsson.com>
Signed-off-by: Darrell Ball <dlu998@gmail.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
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4 people authored and blp committed Feb 12, 2019
1 parent 69c45b3 commit 9171c63532ee9cbc63bb8cfae364ab071f44389b
Showing with 7 additions and 5 deletions.
  1. +7 −5 lib/conntrack.c
@@ -1875,6 +1875,9 @@ extract_l4_icmp6(struct conn_key *key, const void *data, size_t size,
* processed, the function will extract the key from the packet nested
* in the ICMP payload and set '*related' to true.
*
* 'size' here is the layer 4 size, which can be a nested size if parsing
* an ICMP or ICMP6 header.
*
* If 'related' is NULL, it means that we're already parsing a header nested
* in an ICMP error. In this case, we skip checksum and length validation. */
static inline bool
@@ -1949,7 +1952,6 @@ conn_key_extract(struct conntrack *ct, struct dp_packet *pkt, ovs_be16 dl_type,
* we use a sparse representation (miniflow).
*
*/
const char *tail = dp_packet_tail(pkt);
bool ok;
ctx->key.dl_type = dl_type;

@@ -1960,11 +1962,11 @@ conn_key_extract(struct conntrack *ct, struct dp_packet *pkt, ovs_be16 dl_type,
} else {
bool hwol_good_l3_csum = dp_packet_ip_checksum_valid(pkt);
/* Validate the checksum only when hwol is not supported. */
ok = extract_l3_ipv4(&ctx->key, l3, tail - (char *) l3, NULL,
ok = extract_l3_ipv4(&ctx->key, l3, dp_packet_l3_size(pkt), NULL,
!hwol_good_l3_csum);
}
} else if (ctx->key.dl_type == htons(ETH_TYPE_IPV6)) {
ok = extract_l3_ipv6(&ctx->key, l3, tail - (char *) l3, NULL);
ok = extract_l3_ipv6(&ctx->key, l3, dp_packet_l3_size(pkt), NULL);
} else {
ok = false;
}
@@ -1974,8 +1976,8 @@ conn_key_extract(struct conntrack *ct, struct dp_packet *pkt, ovs_be16 dl_type,
if (!hwol_bad_l4_csum) {
bool hwol_good_l4_csum = dp_packet_l4_checksum_valid(pkt);
/* Validate the checksum only when hwol is not supported. */
if (extract_l4(&ctx->key, l4, tail - l4, &ctx->icmp_related, l3,
!hwol_good_l4_csum)) {
if (extract_l4(&ctx->key, l4, dp_packet_l4_size(pkt),
&ctx->icmp_related, l3, !hwol_good_l4_csum)) {
ctx->hash = conn_key_hash(&ctx->key, ct->hash_basis);
return true;
}

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