diff options
| -rw-r--r-- | src/tunnelbridge_cmd.cpp | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp index 9ba9b26e3..5f194a319 100644 --- a/src/tunnelbridge_cmd.cpp +++ b/src/tunnelbridge_cmd.cpp @@ -701,8 +701,22 @@ CommandCost CmdBuildTunnel(TileIndex start_tile, DoCommandFlag flags, uint32 p1, /* Hide the tile from the terraforming command */ TileIndex old_first_tile = coa->first_tile; coa->first_tile = INVALID_TILE; + + /* CMD_TERRAFORM_LAND may append further items to _cleared_object_areas, + * however it will never erase or re-order existing items. + * _cleared_object_areas is a value-type SmallVector, therefore appending items + * may result in a backing-store re-allocation, which would invalidate the coa pointer. + * The index of the coa pointer into the _cleared_object_areas vector remains valid, + * and can be used safely after the CMD_TERRAFORM_LAND operation. + * Deliberately clear the coa pointer to avoid leaving dangling pointers which could + * inadvertently be dereferenced. + */ + assert(coa >= _cleared_object_areas.Begin() && coa < _cleared_object_areas.End()); + size_t coa_index = coa - _cleared_object_areas.Begin(); + coa = NULL; + ret = DoCommand(end_tile, end_tileh & start_tileh, 0, flags, CMD_TERRAFORM_LAND); - coa->first_tile = old_first_tile; + _cleared_object_areas[coa_index].first_tile = old_first_tile; if (ret.Failed()) return_cmd_error(STR_ERROR_UNABLE_TO_EXCAVATE_LAND); cost.AddCost(ret); } |