Signed integer overflow in JsonIn::get_int

[hexagonrecursion]

src/json.cpp:1063:41: runtime error: signed integer overflow: -2147483648 * -1 cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior src/json.cpp:1063:41 in 

(lldb) bt
* thread #1, name = 'cataclysm-tiles', stop reason = Signed integer overflow
  * frame #0: 0x000000000216db50 cataclysm-tiles`__ubsan_on_report
    frame #1: 0x000000000216812d cataclysm-tiles`__ubsan::Diag::~Diag() + 669
    frame #2: 0x000000000216b32c cataclysm-tiles`void handleIntegerOverflowImpl<__ubsan::Value>(__ubsan::OverflowData*, unsigned long, char const*, __ubsan::Value, __ubsan::ReportOptions) + 620
    frame #3: 0x000000000216d1c3 cataclysm-tiles`__ubsan_handle_mul_overflow + 51
    frame #4: 0x0000000003f19111 cataclysm-tiles`JsonIn::get_int(this=<unavailable>) at json.cpp:1063:41
    frame #5: 0x0000000005951fc3 cataclysm-tiles`mission::deserialize(this=0x00007ffffffbb800, jsin=0x00007ffffffbacd0) at savegame_json.cpp:2815:23
    frame #6: 0x00000000058c837b cataclysm-tiles`mission::unserialize_all(jsin=0x00007ffffffbba80) at savegame.cpp:1592:13
    frame #7: 0x00000000058c8719 cataclysm-tiles`game::unserialize_master(this=0x0000619000158180, fin=<unavailable>) at savegame.cpp:1617:17
    frame #8: 0x000000000352aa49 cataclysm-tiles`void std::_Bind<void (game::* (game*, std::_Placeholder<1>))(std::istream&)>::__call<void, std::istream&, 0ul, 1ul>(this=0x000060300b4922c0, __args=0x00007ffffffbbdc0, (null)=<unavailable>) at functional:400:11
    frame #9: 0x000000000352a804 cataclysm-tiles`void std::_Bind<void (game::* (game*, std::_Placeholder<1>))(std::istream&)>::operator(this=0x000060300b4922c0, __args=<unavailable>)<std::istream&, void>(std::istream&) at functional:482:17
    frame #10: 0x00000000029a6a8b cataclysm-tiles`read_from_file(path="./save/Holabird/master.gsav", reader=0x00007ffffffbc2e0)> const&) at cata_utility.cpp:427:9
    frame #11: 0x000000000338e691 cataclysm-tiles`game::load_master(this=0x0000619000158180) at game.cpp:2627:5
    frame #12: 0x0000000003387fb7 cataclysm-tiles`game::start_game(this=0x0000619000158180) at game.cpp:705:5
    frame #13: 0x00000000041afb2a cataclysm-tiles`main_menu::new_character_tab(this=0x00007fffffffdb70) at main_menu.cpp:805:29
    frame #14: 0x00000000041ab41f cataclysm-tiles`main_menu::opening_screen(this=<unavailable>) at main_menu.cpp:539:37
    frame #15: 0x000000000418f5ba cataclysm-tiles`main(argc=<unavailable>, argv=0x00007fffffffe0c8) at main.cpp:683:23
    frame #16: 0x00007ffff78d5f43 libc.so.6`__libc_start_main(main=(cataclysm-tiles`main at main.cpp:135), argc=1, argv=0x00007fffffffe0c8, init=<unavailable>, fini=<unavailable>, rtld_fini=<unavailable>, stack_end=0x00007fffffffe0b8) at libc-start.c:308:16
    frame #17: 0x0000000002054a6e cataclysm-tiles`_start + 46

Steps To Reproduce

Steps to reproduce the behavior:

1. compile with clang UndefinedBehaviorSanitizer
2. Start a new game via "play now (fixed scenario)"

Note that this is not 100% reliable and may take a couple of tries.

Expected behavior

Overflow of signed integer types in C++ should be avoided because it is undefined behavior.

Versions and configuration

• OS: Linux
  • OS Version: Fedora 30
• Game Version: 0.D-11025-g9fe2e72d43 [64-bit]
• Graphics Version: Tiles
• Mods loaded: [
  Dark Days Ahead [dda],
  Disable NPC Needs [no_npc_food]
  ]

[Qrox]

At json.cpp:1063

return static_cast<int>( n.number ) * ( n.negative ? -1 : 1 );

When n.number is 2147483648 it will trigger signed overflow.

This also happens in JsonIn::get_int64.