misc: binary api fuzz test fixes

Add a hook to src/vlibapi/api_shared.c to fuzz (screw up) binary API
messages, e.g. by xoring random data into them before processing. We
specifically exempt client connection messages, and inband debug CLI
messages. We step over msg_id, client index, client context, and
sw_if_index. Otherwise, "make test" vectors fail too rapidly to learn
anything.

The goal is to reduce the number of crashes caused to zero. We're
fairly close with this patch.

Add vl_msg_api_max_length(void *mp), which returns the maximum
plausible length for a binary API message.

Use it to hardern vl_api_from_api_to_new_vec(...) which takes an
additional argument - message pointer - so it can verify that
astr->length is sane. If it's not sane, return a u8 *vector of the
form "insane astr->length nnnn\0".

Verify array lengths in vl_api_dhcp6_send_client_message_t_handler(...)
and vl_api_dhcp6_pd_send_client_message_t_handler(...).

Add a fairly effective binary API fuzz hook to the unittest plugin,
and modify the "make test" framework.py to pass "api-fuzz { on|off }"
to enable API fuzzing: "make API_FUZZ=on TEST=xxx test-debug" or similar

Type: improvement

Signed-off-by: Dave Barach <dave@barachs.net>
Change-Id: I0157267652a163c01553d5267620f719cc6c3bde

7 files changed, 10 insertions, 9 deletions

diff --git a/src/vnet/devices/tap/tapv2_api.c b/src/vnet/devices/tap/tapv2_api.c
index 05679377d2a..5aca93ec310 100644
--- a/src/vnet/devices/tap/tapv2_api.c
+++ b/src/vnet/devices/tap/tapv2_api.c
@@ -134,7 +134,7 @@ vl_api_tap_create_v2_t_handler (vl_api_tap_create_v2_t * mp)
   /* If a tag was supplied... */
   if (vl_api_string_len (&mp->tag))
     {
-      u8 *tag = vl_api_from_api_to_new_vec (&mp->tag);
+      u8 *tag = vl_api_from_api_to_new_vec (mp, &mp->tag);
       vnet_set_sw_interface_tag (vnm, tag, ap->sw_if_index);
     }
 
diff --git a/src/vnet/interface_api.c b/src/vnet/interface_api.c
index 5b24a29efc9..846420d7378 100644
--- a/src/vnet/interface_api.c
+++ b/src/vnet/interface_api.c
@@ -361,7 +361,7 @@ vl_api_sw_interface_dump_t_handler (vl_api_sw_interface_dump_t * mp)
 
   if (mp->name_filter_valid)
     {
-      filter = vl_api_from_api_to_new_vec (&mp->name_filter);
+      filter = vl_api_from_api_to_new_vec (mp, &mp->name_filter);
       vec_add1 (filter, 0);	/* Ensure it's a C string for strcasecmp() */
     }
 
diff --git a/src/vnet/ip/ip_api.c b/src/vnet/ip/ip_api.c
index 3bc46fee59b..d5fa2d32f21 100644
--- a/src/vnet/ip/ip_api.c
+++ b/src/vnet/ip/ip_api.c
@@ -1544,13 +1544,14 @@ static void
 vl_api_ip_punt_redirect_dump_t_handler (vl_api_ip_punt_redirect_dump_t * mp)
 {
   vl_api_registration_t *reg;
-  fib_protocol_t fproto;
+  fib_protocol_t fproto = FIB_PROTOCOL_IP4;
 
   reg = vl_api_client_index_to_registration (mp->client_index);
   if (!reg)
     return;
 
-  fproto = mp->is_ipv6 ? FIB_PROTOCOL_IP6 : FIB_PROTOCOL_IP4;
+  if (mp->is_ipv6 == 1)
+    fproto = FIB_PROTOCOL_IP6;
 
   ip_punt_redirect_walk_ctx_t ctx = {
     .reg = reg,
diff --git a/src/vnet/ip/punt_api.c b/src/vnet/ip/punt_api.c
index 2acf8265dc1..3a964b4b7f5 100644
--- a/src/vnet/ip/punt_api.c
+++ b/src/vnet/ip/punt_api.c
@@ -372,7 +372,7 @@ vl_api_punt_reason_dump_t_handler (vl_api_punt_reason_dump_t * mp)
   punt_reason_dump_walk_ctx_t ctx = {
     .reg = reg,
     .context = mp->context,
-    .name = vl_api_from_api_to_new_vec (&mp->reason.name),
+    .name = vl_api_from_api_to_new_vec (mp, &mp->reason.name),
   };
 
   punt_reason_walk (punt_reason_dump_walk_cb, &ctx);
diff --git a/src/vnet/lldp/lldp_api.c b/src/vnet/lldp/lldp_api.c
index a6d7fb84bb7..ecb75bcac4b 100644
--- a/src/vnet/lldp/lldp_api.c
+++ b/src/vnet/lldp/lldp_api.c
@@ -57,7 +57,7 @@ vl_api_lldp_config_t_handler (vl_api_lldp_config_t * mp)
   int rv = 0;
   u8 *sys_name = 0;
 
-  sys_name = vl_api_from_api_to_new_vec (&mp->system_name);
+  sys_name = vl_api_from_api_to_new_vec (mp, &mp->system_name);
 
   if (lldp_cfg_set (&sys_name, ntohl (mp->tx_hold), ntohl (mp->tx_interval))
       != lldp_ok)
diff --git a/src/vnet/pg/pg_api.c b/src/vnet/pg/pg_api.c
index 18de1e9e8c4..bb58a4f0cec 100644
--- a/src/vnet/pg/pg_api.c
+++ b/src/vnet/pg/pg_api.c
@@ -122,7 +122,7 @@ vl_api_pg_enable_disable_t_handler (vl_api_pg_enable_disable_t * mp)
 
   if (vl_api_string_len (&mp->stream_name) > 0)
     {
-      u8 *stream_name = vl_api_from_api_to_new_vec (&mp->stream_name);
+      u8 *stream_name = vl_api_from_api_to_new_vec (mp, &mp->stream_name);
       uword *p = hash_get_mem (pg->stream_index_by_name, stream_name);
       if (p)
 	stream_index = *p;
diff --git a/src/vnet/session/session_api.c b/src/vnet/session/session_api.c
index cfeb7bcc349..593f2e18ba0 100644
--- a/src/vnet/session/session_api.c
+++ b/src/vnet/session/session_api.c
@@ -624,7 +624,7 @@ vl_api_app_attach_t_handler (vl_api_app_attach_t * mp)
   a->options = mp->options;
   a->session_cb_vft = &session_mq_cb_vft;
 
-  a->namespace_id = vl_api_from_api_to_new_vec (&mp->namespace_id);
+  a->namespace_id = vl_api_from_api_to_new_vec (mp, &mp->namespace_id);
 
   if ((rv = vnet_application_attach (a)))
     {
@@ -801,7 +801,7 @@ vl_api_app_namespace_add_del_t_handler (vl_api_app_namespace_add_del_t * mp)
       goto done;
     }
 
-  ns_id = vl_api_from_api_to_new_vec (&mp->namespace_id);
+  ns_id = vl_api_from_api_to_new_vec (mp, &mp->namespace_id);
 
   vnet_app_namespace_add_del_args_t args = {
     .ns_id = ns_id,