editor: crash when reducing map level size drastically

[matthiaskrgr]

When I try to reduce a level size to 0, the game shuts down with:

Game starts using theme: lanzz
Found highscore file '/home/matthias/.freedroidClassic/highscores'
==6816==AddressSanitizer: WARNING: unexpected format specifier in printf interceptor: %z  (reported once per process)
Failed to re-allocate to % bytes in map row 0
----------------------------------------------------------------------
Termination of Freedroid initiated...Thank you for playing Freedroid.

When I reduce the map to still a few tiles, and exit the editor, I get a crash like

AddressSanitizer:DEADLYSIGNAL
=================================================================
==7110==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000014 (pc 0x0000003912d6 bp 0x7ffead31aaf0 sp 0x7ffead31aaa0 T0)
==7110==The signal is caused by a WRITE memory access.
==7110==Hint: address points to the zero page.
    #0 0x3912d5 in AnimateRefresh /tmp/FreedroidClassic/src/map.c
    #1 0x38ec80 in main /tmp/FreedroidClassic/src/main.c:132:4
    #2 0x7f6fbb9b4222 in __libc_start_main (/usr/lib/libc.so.6+0x24222)
    #3 0x27002d in _start (/tmp/FreedroidClassic/src/freedroid+0x27002d)
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV /tmp/FreedroidClassic/src/map.c in AnimateRefresh

or

Found highscore file '/home/matthias/.freedroidClassic/highscores'
=================================================================
==6995==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000034764 at pc 0x000000391346 bp 0x7ffeeec92c50 sp 0x7ffeeec92c48
WRITE of size 1 at 0x603000034764 thread T0
    #0 0x391345 in AnimateRefresh /tmp/FreedroidClassic/src/map.c:218:27
    #1 0x38ec80 in main /tmp/FreedroidClassic/src/main.c:132:4
    #2 0x7fb931735222 in __libc_start_main (/usr/lib/libc.so.6+0x24222)
    #3 0x27002d in _start (/tmp/FreedroidClassic/src/freedroid+0x27002d)
0x603000034764 is located 3 bytes to the right of 17-byte region [0x603000034750,0x603000034761)
allocated by thread T0 here:
    #0 0x313482 in __interceptor_realloc /home/matthias/LLVM/LLVM6/stage_2/llvm/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:107:3
    #1 0x39e7cf in handle_LE_SizeX /tmp/FreedroidClassic/src/menu.c:525:28
    #2 0x3a3191 in ShowMenu /tmp/FreedroidClassic/src/menu.c:917:13
    #3 0x3a3457 in showLevelEditorMenu /tmp/FreedroidClassic/src/menu.c:703:3
    #4 0x3884eb in LevelEditor /tmp/FreedroidClassic/src/level_editor.c:232:2
    #5 0x3a0252 in handle_OpenLevelEditor /tmp/FreedroidClassic/src/menu.c:465:5
    #6 0x3a31f5 in ShowMenu /tmp/FreedroidClassic/src/menu.c:901:13
    #7 0x3a278d in showMainMenu /tmp/FreedroidClassic/src/menu.c:695:3
    #8 0x37eac9 in ReactToSpecialKeys /tmp/FreedroidClassic/src/input.c:370:5
    #9 0x38ec47 in main /tmp/FreedroidClassic/src/main.c:125:4
    #10 0x7fb931735222 in __libc_start_main (/usr/lib/libc.so.6+0x24222)
SUMMARY: AddressSanitizer: heap-buffer-overflow /tmp/FreedroidClassic/src/map.c:218:27 in AnimateRefresh
Shadow bytes around the buggy address:
  0x0c067fffe890: fd fd fd fa fa fa fd fd fd fa fa fa fd fd fd fa
  0x0c067fffe8a0: fa fa fd fd fd fa fa fa fd fd fd fa fa fa fd fd
  0x0c067fffe8b0: fd fd fa fa fd fd fd fa fa fa fd fd fd fd fa fa
  0x0c067fffe8c0: 00 00 01 fa fa fa 00 00 01 fa fa fa 00 00 01 fa
  0x0c067fffe8d0: fa fa 00 00 01 fa fa fa 00 00 01 fa fa fa 00 00
=>0x0c067fffe8e0: 01 fa fa fa 00 00 01 fa fa fa 00 00[01]fa fa fa
  0x0c067fffe8f0: 00 00 01 fa fa fa 00 00 01 fa fa fa 00 00 01 fa
  0x0c067fffe900: fa fa 00 00 01 fa fa fa 00 00 01 fa fa fa 00 00
  0x0c067fffe910: 01 fa fa fa 00 00 01 fa fa fa fd fd fd fa fa fa
  0x0c067fffe920: fd fd fd fd fa fa fd fd fd fa fa fa fd fd fd fd
  0x0c067fffe930: fa fa fd fd fd fa fa fa fd fd fd fd fa fa fd fd
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

We had similar problems in FreedroidRPG as well where blindly reducing map size (while there was stuff on it) would result in segfaults or buffer problems etc.