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authorDave Barach <dave@barachs.net>2020-04-29 17:04:10 -0400
committerFlorin Coras <florin.coras@gmail.com>2020-05-04 14:03:21 +0000
commit7784140f2bd2d5ae44f2be1507ac25f102006155 (patch)
tree4ac12e04f5177bffab6f3c05d6bf837567a65988 /src/vlibapi/api_shared.c
parentd88fc0fcedb402e3dc82cb44280d4567a6a13266 (diff)
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
Diffstat (limited to 'src/vlibapi/api_shared.c')
-rw-r--r--src/vlibapi/api_shared.c27
1 files changed, 26 insertions, 1 deletions
diff --git a/src/vlibapi/api_shared.c b/src/vlibapi/api_shared.c
index 28e9f481650..fbaa9c9e013 100644
--- a/src/vlibapi/api_shared.c
+++ b/src/vlibapi/api_shared.c
@@ -533,6 +533,8 @@ msg_handler_internal (api_main_t * am,
}
}
+void (*vl_msg_api_fuzz_hook) (u16, void *);
+
/* This is only to be called from a vlib/vnet app */
void
vl_msg_api_handler_with_vm_node (api_main_t * am, svm_region_t * vlib_rp,
@@ -600,6 +602,10 @@ vl_msg_api_handler_with_vm_node (api_main_t * am, svm_region_t * vlib_rp,
am->vlib_rp = vlib_rp;
am->shmem_hdr = (void *) vlib_rp->user_ctx;
}
+
+ if (PREDICT_FALSE (vl_msg_api_fuzz_hook != 0))
+ (*vl_msg_api_fuzz_hook) (id, the_msg);
+
(*handler) (the_msg, vm, node);
if (is_private)
{
@@ -870,6 +876,21 @@ vl_msg_api_queue_handler (svm_queue_t * q)
vl_msg_api_handler ((void *) msg);
}
+u32
+vl_msg_api_max_length (void *mp)
+{
+ msgbuf_t *mb;
+ u32 data_len = ~0;
+
+ /* Work out the maximum sane message length, and return it */
+ if (PREDICT_TRUE (mp != 0))
+ {
+ mb = (msgbuf_t *) (((u8 *) mp) - offsetof (msgbuf_t, data));
+ data_len = clib_net_to_host_u32 (mb->data_len);
+ }
+ return data_len;
+}
+
vl_api_trace_t *
vl_msg_api_trace_get (api_main_t * am, vl_api_trace_which_t which)
{
@@ -1132,9 +1153,13 @@ vl_api_format_string (u8 * s, va_list * args)
* NOT nul terminated.
*/
u8 *
-vl_api_from_api_to_new_vec (vl_api_string_t * astr)
+vl_api_from_api_to_new_vec (void *mp, vl_api_string_t * astr)
{
u8 *v = 0;
+
+ if (vl_msg_api_max_length (mp) < clib_net_to_host_u32 (astr->length))
+ return format (0, "insane astr->length %u%c",
+ clib_net_to_host_u32 (astr->length), 0);
vec_add (v, astr->buf, clib_net_to_host_u32 (astr->length));
return v;
}