From fae014d95769aea3b4f07b182c0fc30018ce1240 Mon Sep 17 00:00:00 2001
From: MysterD <myster@d>
Date: Fri, 28 Jan 2022 19:12:18 -0800
Subject: [PATCH] Prevented packets from overrunning their buffers

---
 src/pc/djui/djui.c                         | 4 +++-
 src/pc/djui/djui_cursor.c                  | 2 +-
 src/pc/network/network.c                   | 3 +++
 src/pc/network/packets/packet.h            | 1 +
 src/pc/network/packets/packet_read_write.c | 6 ++++++
 src/pc/network/packets/packet_reliable.c   | 1 +
 6 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/pc/djui/djui.c b/src/pc/djui/djui.c
index e0768536e..a49434d86 100644
--- a/src/pc/djui/djui.c
+++ b/src/pc/djui/djui.c
@@ -55,7 +55,9 @@ void djui_render(void) {
     djui_popup_update();
 
     djui_base_set_visible(&sDjuiPauseOptions->base, (sCurrPlayMode == PLAY_MODE_PAUSED));
-    djui_base_render(&gDjuiRoot->base);
+    if (gDjuiRoot != NULL) {
+        djui_base_render(&gDjuiRoot->base);
+    }
 
     djui_cursor_update();
     djui_interactable_update();
diff --git a/src/pc/djui/djui_cursor.c b/src/pc/djui/djui_cursor.c
index 3465414a9..4860d279c 100644
--- a/src/pc/djui/djui_cursor.c
+++ b/src/pc/djui/djui_cursor.c
@@ -7,7 +7,7 @@
 extern ALIGNED8 u8 gd_texture_hand_open[];
 extern ALIGNED8 u8 gd_texture_hand_closed[];
 
-static struct DjuiImage* sMouseCursor = NULL;
+struct DjuiImage* sMouseCursor = NULL;
 
 static bool sCursorMouseControlled = false;
 static struct DjuiBase* sInputControlledBase = NULL;
diff --git a/src/pc/network/network.c b/src/pc/network/network.c
index 8991db987..13084ab6b 100644
--- a/src/pc/network/network.c
+++ b/src/pc/network/network.c
@@ -230,6 +230,9 @@ void network_send_to(u8 localIndex, struct Packet* p) {
 }
 
 void network_send(struct Packet* p) {
+    // prevent errors during writing from propagating
+    if (p->writeError) { return; }
+
     // set the flags again
     packet_set_flags(p);
 
diff --git a/src/pc/network/packets/packet.h b/src/pc/network/packets/packet.h
index e91ca022b..84724c41a 100644
--- a/src/pc/network/packets/packet.h
+++ b/src/pc/network/packets/packet.h
@@ -76,6 +76,7 @@ struct Packet {
     u16 cursor;
     void* addr;
     bool error;
+    bool writeError;
     bool reliable;
     bool levelAreaMustMatch;
     bool levelMustMatch;
diff --git a/src/pc/network/packets/packet_read_write.c b/src/pc/network/packets/packet_read_write.c
index 61f4091d6..f2ef35955 100644
--- a/src/pc/network/packets/packet_read_write.c
+++ b/src/pc/network/packets/packet_read_write.c
@@ -18,6 +18,7 @@ void packet_init(struct Packet* packet, enum PacketType packetType, bool reliabl
     packet->cursor = 0;
     packet->dataLength = 0;
     packet->error = false;
+    packet->writeError = false;
     packet->reliable = reliable;
     packet->levelAreaMustMatch = (levelAreaMustMatch == PLMT_AREA);
     packet->levelMustMatch     = (levelAreaMustMatch == PLMT_LEVEL);
@@ -82,6 +83,7 @@ void packet_duplicate(struct Packet* srcPacket, struct Packet* dstPacket) {
     dstPacket->cursor = 0;
     dstPacket->dataLength = 0;
     dstPacket->error = srcPacket->error;
+    dstPacket->writeError = srcPacket->writeError;
     dstPacket->reliable = srcPacket->reliable;
     dstPacket->levelAreaMustMatch = srcPacket->levelAreaMustMatch;
     dstPacket->levelMustMatch = srcPacket->levelMustMatch;
@@ -125,6 +127,10 @@ void packet_set_destination(struct Packet* packet, u8 destGlobalId) {
 
 void packet_write(struct Packet* packet, void* data, u16 length) {
     if (data == NULL) { packet->error = true; return; }
+    if (packet->cursor + length >= PACKET_LENGTH) {
+        SOFT_ASSERT(packet->cursor + length < PACKET_LENGTH);
+        packet->writeError = true;
+    }
     memcpy(&packet->buffer[packet->cursor], data, length);
     packet->dataLength += length;
     packet->cursor     += length;
diff --git a/src/pc/network/packets/packet_reliable.c b/src/pc/network/packets/packet_reliable.c
index 3e433f342..729ec42e1 100644
--- a/src/pc/network/packets/packet_reliable.c
+++ b/src/pc/network/packets/packet_reliable.c
@@ -86,6 +86,7 @@ void network_receive_ack(struct Packet* p) {
 void network_remember_reliable(struct Packet* p) {
     if (!p->reliable) { return; }
     if (p->sent) { return; }
+    if (p->writeError) { return; }
 
     struct PacketLinkedList* node = calloc(1, sizeof(struct PacketLinkedList));
     node->p = *p;