diff options
Diffstat (limited to 'cube.c')
| -rw-r--r-- | cube.c | 24 |
1 files changed, 24 insertions, 0 deletions
@@ -542,12 +542,36 @@ static const char *validate_params(const game_params *params, bool full) if (params->solid < 0 || params->solid >= lenof(solids)) return "Unrecognised solid type"; + if (params->d1 < 0 || params->d2 < 0) + return "Grid dimensions may not be negative"; + if (solids[params->solid]->order == 4) { if (params->d1 <= 1 || params->d2 <= 1) return "Both grid dimensions must be greater than one"; + if (params->d2 > INT_MAX / params->d1) + return "Grid area must not be unreasonably large"; } else { if (params->d1 <= 0 && params->d2 <= 0) return "At least one grid dimension must be greater than zero"; + + /* + * Check whether d1^2 + d2^2 + 4 d1 d2 > INT_MAX, without overflow: + * + * First check d1^2 doesn't overflow by itself. + * + * Then check d2^2 doesn't exceed the remaining space between + * d1^2 and INT_MAX. + * + * If that's all OK then we know both d1 and d2 are + * individually less than the square root of INT_MAX, so we + * can safely multiply them and compare against the + * _remaining_ space. + */ + if ((params->d1 > INT_MAX / params->d1) || + (params->d2 > (INT_MAX - params->d1*params->d1) / params->d2) || + (params->d1*params->d2 > (INT_MAX - params->d1*params->d1 - + params->d2*params->d2) / params->d2)) + return "Grid area must not be unreasonably large"; } for (i = 0; i < 4; i++) |