From 1ead6acea55028dcf2e6ba0fec8b0127a993d8a5 Mon Sep 17 00:00:00 2001
From: Steve Karg <steve@kargs.net>
Date: Wed, 15 Apr 2020 00:03:21 -0500
Subject: [PATCH] Fix BACnet IPv4 decode to allow for NULL (#72)

Co-authored-by: Steve Karg <skarg@users.sourceforge.net>
---
 src/bacnet/basic/bbmd/h_bbmd.c | 10 ++++-
 src/bacnet/datalink/bvlc.c     | 68 ++++++++++++++--------------------
 2 files changed, 37 insertions(+), 41 deletions(-)

diff --git a/src/bacnet/basic/bbmd/h_bbmd.c b/src/bacnet/basic/bbmd/h_bbmd.c
index 51449aa6..fd042b1b 100644
--- a/src/bacnet/basic/bbmd/h_bbmd.c
+++ b/src/bacnet/basic/bbmd/h_bbmd.c
@@ -1042,6 +1042,9 @@ int bvlc_bbmd_enabled_handler(BACNET_IP_ADDRESS *addr,
                 bvlc_ip_address_to_bacnet_local(src, addr);
                 offset = header_len + function_len - npdu_len;
                 debug_print_npdu("Original-Unicast-NPDU", offset, npdu_len);
+            } else {
+                debug_print_string(
+                    "Original-Broadcast-NPDU: Unable to decode!");
             }
             break;
         case BVLC_ORIGINAL_BROADCAST_NPDU:
@@ -1074,6 +1077,9 @@ int bvlc_bbmd_enabled_handler(BACNET_IP_ADDRESS *addr,
                 bbmd_fdt_forward_npdu(addr, npdu, npdu_len, true);
                 bbmd_bdt_forward_npdu(addr, npdu, npdu_len, true);
                 debug_print_npdu("Original-Broadcast-NPDU", offset, npdu_len);
+            } else {
+                debug_print_string(
+                    "Original-Broadcast-NPDU: Unable to decode!");
             }
             break;
         case BVLC_SECURE_BVLL:
@@ -1245,10 +1251,12 @@ void bvlc_disable_nat(void)
 
 void bvlc_init(void)
 {
-    debug_print_string("Initializing.");
 #if BBMD_ENABLED
+    debug_print_string("Initializing (BBMD Enabled).");
     bvlc_broadcast_distribution_table_link_array(
         &BBMD_Table[0], MAX_BBMD_ENTRIES);
     bvlc_foreign_device_table_link_array(&FD_Table[0], MAX_FD_ENTRIES);
+#else
+    debug_print_string("Initializing (BBMD Disabled).");
 #endif
 }
diff --git a/src/bacnet/datalink/bvlc.c b/src/bacnet/datalink/bvlc.c
index 448c125a..7094a2c5 100644
--- a/src/bacnet/datalink/bvlc.c
+++ b/src/bacnet/datalink/bvlc.c
@@ -1385,19 +1385,15 @@ int bvlc_decode_distribute_broadcast_to_network(uint8_t *pdu,
     int bytes_consumed = 0;
     uint16_t i = 0;
 
-    if (pdu) {
-        if ((pdu_len > 0) && (pdu_len <= npdu_size)) {
-            if (npdu) {
-                for (i = 0; i < pdu_len; i++) {
-                    npdu[i] = pdu[i];
-                }
-            }
+    if (pdu && npdu && (pdu_len > 0) && (pdu_len <= npdu_size)) {
+        for (i = 0; i < pdu_len; i++) {
+            npdu[i] = pdu[i];
         }
-        if (npdu_len) {
-            *npdu_len = pdu_len;
-        }
-        bytes_consumed = (int)pdu_len;
     }
+    if (npdu_len) {
+        *npdu_len = pdu_len;
+    }
+    bytes_consumed = (int)pdu_len;
 
     return bytes_consumed;
 }
@@ -1464,17 +1460,15 @@ int bvlc_decode_original_unicast(uint8_t *pdu,
     int bytes_consumed = 0;
     uint16_t i = 0;
 
-    if (pdu_len <= npdu_size) {
-        if (pdu && npdu) {
-            for (i = 0; i < pdu_len; i++) {
-                npdu[i] = pdu[i];
-            }
+    if (pdu && npdu && (pdu_len > 0) && (pdu_len <= npdu_size)) {
+        for (i = 0; i < pdu_len; i++) {
+            npdu[i] = pdu[i];
         }
-        if (npdu_len) {
-            *npdu_len = pdu_len;
-        }
-        bytes_consumed = (int)pdu_len;
     }
+    if (npdu_len) {
+        *npdu_len = pdu_len;
+    }
+    bytes_consumed = (int)pdu_len;
 
     return bytes_consumed;
 }
@@ -1541,17 +1535,15 @@ int bvlc_decode_original_broadcast(uint8_t *pdu,
     int bytes_consumed = 0;
     uint16_t i = 0;
 
-    if (pdu_len <= npdu_size) {
-        if (pdu && npdu) {
-            for (i = 0; i < pdu_len; i++) {
-                npdu[i] = pdu[i];
-            }
+    if (pdu && npdu && (pdu_len > 0) && (pdu_len <= npdu_size)) {
+        for (i = 0; i < pdu_len; i++) {
+            npdu[i] = pdu[i];
         }
-        if (npdu_len) {
-            *npdu_len = pdu_len;
-        }
-        bytes_consumed = (int)pdu_len;
     }
+    if (npdu_len) {
+        *npdu_len = pdu_len;
+    }
+    bytes_consumed = (int)pdu_len;
 
     return bytes_consumed;
 }
@@ -1618,19 +1610,15 @@ int bvlc_decode_secure_bvll(uint8_t *pdu,
     int bytes_consumed = 0;
     uint16_t i = 0;
 
-    if (pdu) {
-        if (sbuf_len) {
-            *sbuf_len = pdu_len;
+    if (pdu && sbuf && (pdu_len > 0) && (pdu_len <= sbuf_size)) {
+        for (i = 0; i < pdu_len; i++) {
+            sbuf[i] = pdu[i];
         }
-        if (pdu_len) {
-            if (sbuf) {
-                for (i = 0; i < pdu_len; i++) {
-                    sbuf[i] = pdu[i];
-                }
-            }
-        }
-        bytes_consumed = (int)pdu_len;
     }
+    if (sbuf_len) {
+        *sbuf_len = pdu_len;
+    }
+    bytes_consumed = (int)pdu_len;
 
     return bytes_consumed;
 }