Heap buffer overflow (read) while loading map in CRenderTools::RenderQuads, render_map.cpp:237

[mmmds]

The client crashes (only with ASAN) when an invalid map (10.map.zip) is loaded. Such a map can be delivered to the client by a malicious server.

Tested on Ubuntu 20.04 x86_64, Teeworlds version: f35da54b6f2c5f9fd4bbd4559f887ccf8f8cc526

Compilation with ASAN:

export CXXFLAGS="-ggdb -O0 -fsanitize=address -fno-omit-frame-pointer"
export CFLAGS="-ggdb -O0 -fsanitize=address -fno-omit-frame-pointer"
cmake ..
make

Run and connect to a server that delivers an invalid map:

./teeworlds "connect 127.0.0.1" "gfx_fullscreen 0" "gfx_screen_height 240" "gfx_screen_width 360"
[...]
=================================================================
==33614==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x60b0000ea3b0 at pc 0x555555853cb1 bp 0x7fffffffb1e0 sp 0x7fffffffb1d0
READ of size 4 at 0x60b0000ea3b0 thread T0
    #0 0x555555853cb0 in CRenderTools::RenderQuads(CQuad*, int, int, void (*)(float, int, float*, void*), void*) /home/osboxes/teeworlds/teeworlds-asan/src/game/client/render_map.cpp:237
    #1 0x5555556f75f1 in CMapLayers::OnRender() /home/osboxes/teeworlds/teeworlds-asan/src/game/client/components/maplayers.cpp:375
    #2 0x555555827989 in CGameClient::OnRender() /home/osboxes/teeworlds/teeworlds-asan/src/game/client/gameclient.cpp:611
    #3 0x5555555fce4e in CClient::Render() /home/osboxes/teeworlds/teeworlds-asan/src/engine/client/client.cpp:796
    #4 0x5555555fce4e in CClient::Run() /home/osboxes/teeworlds/teeworlds-asan/src/engine/client/client.cpp:2131
    #5 0x5555555d24e5 in main /home/osboxes/teeworlds/teeworlds-asan/src/engine/client/client.cpp:2704
    #6 0x7ffff68e10b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #7 0x5555555dc48d in _start (/home/osboxes/teeworlds/teeworlds-asan/build/teeworlds+0x8848d)

Address 0x60b0000ea3b0 is a wild pointer.
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/osboxes/teeworlds/teeworlds-asan/src/game/client/render_map.cpp:237 in CRenderTools::RenderQuads(CQuad*, int, int, void (*)(float, int, float*, void*), void*)
Shadow bytes around the buggy address:
  0x0c1680015420: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1680015430: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1680015440: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1680015450: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1680015460: fa fa fa fa 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c1680015470: 04 fa fa fa fa fa[fa]fa fa fa fa fa fa fa fa fa
  0x0c1680015480: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c1680015490: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c16800154a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c16800154b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c16800154c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07 
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
  Shadow gap:              cc
==33614==ABORTING

Doesn't crash without ASAN.