dpif: Fix leak and usage of uninitialized dp_extra_info.

'dpif_probe_feature'/'revalidate' doesn't free the 'dp_extra_info'
string.  Also, all the implementations of dpif_flow_get() should
initialize the value to avoid printing/freeing of random memory.

 30 bytes in 1 blocks are definitely lost in loss record 323 of 889
    at 0x483AD19: realloc (vg_replace_malloc.c:836)
    by 0xDDAD89: xrealloc (util.c:149)
    by 0xCE1609: ds_reserve (dynamic-string.c:63)
    by 0xCE1A90: ds_put_format_valist (dynamic-string.c:161)
    by 0xCE19B9: ds_put_format (dynamic-string.c:142)
    by 0xCCCEA9: dp_netdev_flow_to_dpif_flow (dpif-netdev.c:3170)
    by 0xCCD2DD: dpif_netdev_flow_get (dpif-netdev.c:3278)
    by 0xCCEA0A: dpif_netdev_operate (dpif-netdev.c:3868)
    by 0xCDF81B: dpif_operate (dpif.c:1361)
    by 0xCDEE93: dpif_flow_get (dpif.c:1002)
    by 0xCDECF9: dpif_probe_feature (dpif.c:962)
    by 0xC635D2: check_recirc (ofproto-dpif.c:896)
    by 0xC65C02: check_support (ofproto-dpif.c:1567)
    by 0xC63274: open_dpif_backer (ofproto-dpif.c:818)
    by 0xC65E3E: construct (ofproto-dpif.c:1605)
    by 0xC4D436: ofproto_create (ofproto.c:549)
    by 0xC3931A: bridge_reconfigure (bridge.c:877)
    by 0xC3FEAC: bridge_run (bridge.c:3324)
    by 0xC4551D: main (ovs-vswitchd.c:127)

CC: Emma Finn <emma.finn@intel.com>
Fixes: 0e8f5c6a38d0 ("dpif-netdev: Modified ovs-appctl dpctl/dump-flows command")
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Acked-by: Roi Dayan <roid@mellanox.com>

5 files changed, 8 insertions, 3 deletions

diff --git a/lib/dpif-netlink.c b/lib/dpif-netlink.c
index d865c0bdb..5b5c96d72 100644
--- a/lib/dpif-netlink.c
+++ b/lib/dpif-netlink.c
@@ -1590,6 +1590,7 @@ dpif_netlink_flow_to_dpif_flow(struct dpif_flow *dpif_flow,
     dpif_netlink_flow_get_stats(datapath_flow, &dpif_flow->stats);
     dpif_flow->attrs.offloaded = false;
     dpif_flow->attrs.dp_layer = "ovs";
+    dpif_flow->attrs.dp_extra_info = NULL;
 }
 
 /* The design is such that all threads are working together on the first dump
diff --git a/lib/dpif.c b/lib/dpif.c
index 9d9c716c1..6cbcdfb2e 100644
--- a/lib/dpif.c
+++ b/lib/dpif.c
@@ -966,6 +966,7 @@ dpif_probe_feature(struct dpif *dpif, const char *name,
                       && ovs_u128_equals(*ufid, flow.ufid)))) {
         enable_feature = true;
     }
+    free(flow.attrs.dp_extra_info);
 
     error = dpif_flow_del(dpif, key->data, key->size, ufid,
                           NON_PMD_CORE_ID, NULL);
diff --git a/lib/dpif.h b/lib/dpif.h
index 59d82dce3..286a0e2d5 100644
--- a/lib/dpif.h
+++ b/lib/dpif.h
@@ -741,11 +741,12 @@ struct dpif_execute {
  * 'buffer' must point to an initialized buffer, with a recommended size of
  * DPIF_FLOW_BUFSIZE bytes.
  *
- * On success, 'flow' will be populated with the mask, actions and stats for
- * the datapath flow corresponding to 'key'. The mask and actions may point
+ * On success, 'flow' will be populated with the mask, actions, stats and attrs
+ * for the datapath flow corresponding to 'key'. The mask and actions may point
  * within '*buffer', or may point at RCU-protected data. Therefore, callers
  * that wish to hold these over quiescent periods must make a copy of these
- * fields before quiescing.
+ * fields before quiescing.  'attrs.dp_extra_info' is a dynamically allocated
+ * string that should be freed if provided by the datapath.
  *
  * Callers should always provide 'key' to improve dpif logging in the event of
  * errors or unexpected behaviour.
diff --git a/lib/netdev-offload-dpdk.c b/lib/netdev-offload-dpdk.c
index 1ae8230fa..f8c46bbaa 100644
--- a/lib/netdev-offload-dpdk.c
+++ b/lib/netdev-offload-dpdk.c
@@ -1272,6 +1272,7 @@ netdev_offload_dpdk_flow_get(struct netdev *netdev,
     }
     memcpy(stats, &rte_flow_data->stats, sizeof *stats);
 out:
+    attrs->dp_extra_info = NULL;
     return ret;
 }
 
diff --git a/lib/netdev-offload-tc.c b/lib/netdev-offload-tc.c
index 4988dadc3..723ec376d 100644
--- a/lib/netdev-offload-tc.c
+++ b/lib/netdev-offload-tc.c
@@ -873,6 +873,7 @@ parse_tc_flower_to_match(struct tc_flower *flower,
     attrs->offloaded = (flower->offloaded_state == TC_OFFLOADED_STATE_IN_HW)
                        || (flower->offloaded_state == TC_OFFLOADED_STATE_UNDEFINED);
     attrs->dp_layer = "tc";
+    attrs->dp_extra_info = NULL;
 
     return 0;
 }