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dpif-netdev: Initialize packet RSS hash in dpif_netdev_execute().

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The datapath code expects the RSS hash to always be initialized.  This
is enforced by checking in emc_processing() that the hash is valid, and
eventually by computing a new one.

Unfortunately, there is another entry point to the datapath,
dpif_netdev_execute().  A packet generated by OVS (BFD frame,
packet-out from controller) doesn't have a valid RSS hash and so is
allowed to enter the datapath with an uninitialized hash value.

This commit recomputes the hash (if not valid) in dpif_netdev_execute().

The only place where we would use an invalid hash is netdev-vport, in
push_udp_header().  This caused an uninitialized memory read, and a
random value to be assigned to the outer tunnel header source port.

Reported-by: William Tu <u9012063@gmail.com>
Signed-off-by: Daniele Di Proietto <diproiettod@vmware.com>
Acked-by: William Tu <u9012063@gmail.com>
Acked-by: Ben Pfaff <blp@ovn.org>
This commit is contained in:
Daniele Di Proietto
2016-05-17 18:38:20 -07:00
parent 1cceb31bc1
commit 36d8de17ff
1 changed files with 11 additions and 0 deletions
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11
lib/dpif-netdev.c
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@@ -2364,9 +2364,20 @@ dpif_netdev_execute(struct dpif *dpif, struct dpif_execute *execute)
ovs_mutex_lock(&dp->port_mutex);
}
/* The action processing expects the RSS hash to be valid, because
* it's always initialized at the beginning of datapath processing.
* In this case, though, 'execute->packet' may not have gone through
* the datapath at all, it may have been generated by the upper layer
* (OpenFlow packet-out, BFD frame, ...). */
if (!dp_packet_rss_valid(execute->packet)) {
dp_packet_set_rss_hash(execute->packet,
flow_hash_5tuple(execute->flow, 0));
}
packet_batch_init_packet(&pp, execute->packet);
dp_netdev_execute_actions(pmd, &pp, false, execute->actions,
execute->actions_len);
if (pmd->core_id == NON_PMD_CORE_ID) {
dp_netdev_pmd_unref(pmd);
ovs_mutex_unlock(&dp->port_mutex);