ofproto-dpif: Fix using uninitialised memory in user_action_cookie.

Designated initializers are not suitable for initializing non-packed
structures and unions which are subjects for comparison by memcmp().

Whole memory for 'struct user_action_cookie' must be explicitly cleared
before using because it will be copied with memcpy and later compared
by memcmp in ofpbuf_equal().

Few issues found be valgrind:

 Thread 13 revalidator11:
 Conditional jump or move depends on uninitialised value(s)
    at 0x4C35D96: __memcmp_sse4_1 (in vgpreload_memcheck.so)
    by 0x9D4404: ofpbuf_equal (ofpbuf.h:273)
    by 0x9D4404: revalidate_ukey__ (ofproto-dpif-upcall.c:2219)
    by 0x9D4404: revalidate_ukey (ofproto-dpif-upcall.c:2286)
    by 0x9D62AC: revalidate (ofproto-dpif-upcall.c:2685)
    by 0x9D62AC: udpif_revalidator (ofproto-dpif-upcall.c:942)
    by 0xA9C732: ovsthread_wrapper (ovs-thread.c:383)
    by 0x5FF86DA: start_thread (pthread_create.c:463)
    by 0x6AF488E: clone (clone.S:95)
  Uninitialised value was created by a stack allocation
    at 0x9D4450: compose_slow_path (ofproto-dpif-upcall.c:1062)

 Thread 11 revalidator16:
 Conditional jump or move depends on uninitialised value(s)
    at 0x4C35D96: __memcmp_sse4_1 (in vgpreload_memcheck.so)
    by 0x9D4404: ofpbuf_equal (ofpbuf.h:273)
    by 0x9D4404: revalidate_ukey__ (ofproto-dpif-upcall.c:2220)
    by 0x9D4404: revalidate_ukey (ofproto-dpif-upcall.c:2287)
    by 0x9D62BC: revalidate (ofproto-dpif-upcall.c:2686)
    by 0x9D62BC: udpif_revalidator (ofproto-dpif-upcall.c:942)
    by 0xA9C6D2: ovsthread_wrapper (ovs-thread.c:383)
    by 0x5FF86DA: start_thread (pthread_create.c:463)
    by 0x6AF488E: clone (clone.S:95)
  Uninitialised value was created by a stack allocation
    at 0x9DC4E0: compose_sflow_action (ofproto-dpif-xlate.c:3211)

The struct was never marked as 'packed', however it was manually
adjusted to be so in practice.
Old IPFIX related commit first made the structure non-contiguous.
Commit 8de6ff3 ("ofproto-dpif: Use a fixed size userspace cookie.")
added uninitialized parts of the additional union space and the next
one introduced new holes between structure fields for all cases.

Change-Id: I6895b1a8ed41f84cb3124e1b5932c0baee26bdea
CC: Justin Pettit <jpettit@ovn.org>
Fixes: 8b7ea2d ("Extend OVS IPFIX exporter to export tunnel headers")
Fixes: 8de6ff3 ("ofproto-dpif: Use a fixed size userspace cookie.")
Fixes: fcb9579 ("ofproto: Add 'ofproto_uuid' and 'ofp_in_port' to user action cookie.")
Signed-off-by: Ilya Maximets <i.maximets@samsung.com>

ofproto/ofproto-dpif-upcall.c

@@ -1064,6 +1064,7 @@ compose_slow_path(struct udpif *udpif, struct xlate_out *xout,
     odp_port_t port;
     uint32_t pid;
 
+    memset(&cookie, 0, sizeof cookie);
     cookie.type = USER_ACTION_COOKIE_SLOW_PATH;
     cookie.ofp_in_port = ofp_in_port;
     cookie.ofproto_uuid = *ofproto_uuid;

ofproto/ofproto-dpif-xlate.c

@@ -3214,11 +3214,13 @@ compose_sflow_action(struct xlate_ctx *ctx)
         return 0;
     }
 
-    struct user_action_cookie cookie = {
-        .type = USER_ACTION_COOKIE_SFLOW,
-        .ofp_in_port = ctx->xin->flow.in_port.ofp_port,
-        .ofproto_uuid = ctx->xbridge->ofproto->uuid
-    };
+    struct user_action_cookie cookie;
+
+    memset(&cookie, 0, sizeof cookie);
+    cookie.type = USER_ACTION_COOKIE_SFLOW;
+    cookie.ofp_in_port = ctx->xin->flow.in_port.ofp_port;
+    cookie.ofproto_uuid = ctx->xbridge->ofproto->uuid;
+
     return compose_sample_action(ctx, dpif_sflow_get_probability(sflow),
                                  &cookie, ODPP_NONE, true);
 }
@@ -3258,12 +3260,14 @@ compose_ipfix_action(struct xlate_ctx *ctx, odp_port_t output_odp_port)
         }
     }
 
-    struct user_action_cookie cookie = {
-        .type = USER_ACTION_COOKIE_IPFIX,
-        .ofp_in_port = ctx->xin->flow.in_port.ofp_port,
-        .ofproto_uuid = ctx->xbridge->ofproto->uuid,
-        .ipfix.output_odp_port = output_odp_port
-    };
+    struct user_action_cookie cookie;
+
+    memset(&cookie, 0, sizeof cookie);
+    cookie.type = USER_ACTION_COOKIE_IPFIX;
+    cookie.ofp_in_port = ctx->xin->flow.in_port.ofp_port;
+    cookie.ofproto_uuid = ctx->xbridge->ofproto->uuid;
+    cookie.ipfix.output_odp_port = output_odp_port;
+
     compose_sample_action(ctx,
                           dpif_ipfix_get_bridge_exporter_probability(ipfix),
                           &cookie, tunnel_out_port, false);
@@ -5521,19 +5525,19 @@ xlate_sample_action(struct xlate_ctx *ctx,
         }
     }
 
-    struct user_action_cookie cookie = {
-        .type = USER_ACTION_COOKIE_FLOW_SAMPLE,
-        .ofp_in_port = ctx->xin->flow.in_port.ofp_port,
-        .ofproto_uuid = ctx->xbridge->ofproto->uuid,
-        .flow_sample = {
-            .probability = os->probability,
-            .collector_set_id = os->collector_set_id,
-            .obs_domain_id = os->obs_domain_id,
-            .obs_point_id = os->obs_point_id,
-            .output_odp_port = output_odp_port,
-            .direction = os->direction,
-        }
-    };
+    struct user_action_cookie cookie;
+
+    memset(&cookie, 0, sizeof cookie);
+    cookie.type = USER_ACTION_COOKIE_FLOW_SAMPLE,
+    cookie.ofp_in_port = ctx->xin->flow.in_port.ofp_port,
+    cookie.ofproto_uuid = ctx->xbridge->ofproto->uuid,
+    cookie.flow_sample.probability = os->probability,
+    cookie.flow_sample.collector_set_id = os->collector_set_id,
+    cookie.flow_sample.obs_domain_id = os->obs_domain_id,
+    cookie.flow_sample.obs_point_id = os->obs_point_id,
+    cookie.flow_sample.output_odp_port = output_odp_port,
+    cookie.flow_sample.direction = os->direction,
+
     compose_sample_action(ctx, probability, &cookie, tunnel_out_port, false);
 }