Heap use after free (read) while running client in CMenus::CBrowserFilter::Switch, menus_browser.cpp:86

[mmmds]

The client crashes (only with ASAN) when it starts using default configuration.

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

Remove default configuration, run the game twice (to generate configuration and then to trigger the bug)

rm -rf ~/.local/share/teeworlds/
./teeworlds
./teeworlds
[...]
=================================================================
==4084==ERROR: AddressSanitizer: heap-use-after-free on address 0x6130000123a0 at pc 0x5602badd13af bp 0x7ffdbba67410 sp 0x7ffdbba67400
READ of size 1 at 0x6130000123a0 thread T0
    #0 0x5602badd13ae in CMenus::CBrowserFilter::Switch() /home/osboxes/teeworlds/teeworlds-asan/src/game/client/components/menus_browser.cpp:86
    #1 0x5602badd13ae in CMenus::LoadFilters() /home/osboxes/teeworlds/teeworlds-asan/src/game/client/components/menus_browser.cpp:261
    #2 0x5602badc9d6c in CMenus::OnInit() /home/osboxes/teeworlds/teeworlds-asan/src/game/client/components/menus.cpp:1173
    #3 0x5602baed6f88 in CGameClient::OnInit() /home/osboxes/teeworlds/teeworlds-asan/src/game/client/gameclient.cpp:390
    #4 0x5602baca2485 in CClient::Run() /home/osboxes/teeworlds/teeworlds-asan/src/engine/client/client.cpp:1997
    #5 0x5602bac794e5 in main /home/osboxes/teeworlds/teeworlds-asan/src/engine/client/client.cpp:2704
    #6 0x7fadf7bac0b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #7 0x5602bac8348d in _start (/home/osboxes/teeworlds/teeworlds-asan/build/teeworlds+0x8848d)

0x6130000123a0 is located 224 bytes inside of 384-byte region [0x6130000122c0,0x613000012440)
freed by thread T0 here:
    #0 0x7fadf89597cf in __interceptor_free (/lib/x86_64-linux-gnu/libasan.so.5+0x10d7cf)
    #1 0x7fadf8488fcf in FT_Outline_Done (/lib/x86_64-linux-gnu/libfreetype.so.6+0x10fcf)

previously allocated by thread T0 here:
    #0 0x7fadf8959bc8 in malloc (/lib/x86_64-linux-gnu/libasan.so.5+0x10dbc8)
    #1 0x7fadf848d771  (/lib/x86_64-linux-gnu/libfreetype.so.6+0x15771)

SUMMARY: AddressSanitizer: heap-use-after-free /home/osboxes/teeworlds/teeworlds-asan/src/game/client/components/menus_browser.cpp:86 in CMenus::CBrowserFilter::Switch()
Shadow bytes around the buggy address:
  0x0c267fffa420: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c267fffa430: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c267fffa440: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
  0x0c267fffa450: fa fa fa fa fa fa fa fa fd fd fd fd fd fd fd fd
  0x0c267fffa460: fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd fd
=>0x0c267fffa470: fd fd fd fd[fd]fd fd fd fd fd fd fd fd fd fd fd
  0x0c267fffa480: fd fd fd fd fd fd fd fd fa fa fa fa fa fa fa fa
  0x0c267fffa490: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c267fffa4a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c267fffa4b0: 00 00 00 00 00 00 00 00 00 00 fa fa fa fa fa fa
  0x0c267fffa4c0: 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
==4084==ABORTING

[Robyt3]

I'll handle this one. The others are all map related, so #2931 is probably related.