Merge branch 'bugfix/sig_ble_mesh_errata_e16350_v4.3' into 'release/v4.3'

ble_mesh: stack: Apply the errata E16350 from Bluetooth SIG (v4.3)

See merge request espressif/esp-idf!15784

components/bt/esp_ble_mesh/mesh_core/prov.c

@@ -840,6 +840,7 @@ static void prov_start(const uint8_t *data)
 
 static void send_confirm(void)
 {
+    uint8_t *local_conf = NULL;
     PROV_BUF(cfm, 17);
 
     BT_DBG("ConfInputs[0]   %s", bt_hex(link.conf_inputs, 64));
@@ -872,13 +873,21 @@ static void send_confirm(void)
 
     prov_buf_init(&cfm, PROV_CONFIRM);
 
+    local_conf = net_buf_simple_add(&cfm, 16);
+
     if (bt_mesh_prov_conf(link.conf_key, link.rand, link.auth,
-                          net_buf_simple_add(&cfm, 16))) {
+                          local_conf)) {
         BT_ERR("Unable to generate confirmation value");
         prov_send_fail_msg(PROV_ERR_UNEXP_ERR);
         return;
     }
 
+    if (!memcmp(link.conf, local_conf, 16)) {
+        BT_ERR("Confirmation value is identical to ours, rejecting.");
+        prov_send_fail_msg(PROV_ERR_NVAL_FMT);
+        return;
+    }
+
     if (prov_send(&cfm)) {
         BT_ERR("Unable to send Provisioning Confirm");
         return;