URL:
<http://gna.org/bugs/?17577>
Summary: Invalid wesnoth.set_terrain() in [lua] will crash
Wesnoth
Project: Battle for Wesnoth
Submitted by: aethaeryn
Submitted on: Wed 26 Jan 2011 05:37:17 AM GMT
Category: Bug
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: WML
Status: None
Privacy: Public
Assigned to: None
Originator Email:
Open/Closed: Open
Discussion Lock: Any
Release: 1.9.4+svn r48376
Operating System: Fedora 14
_______________________________________________________
Details:
I'm using 1.9.4+svn r48376 on Fedora 14 compiled with scons and I happened to
find an interesting bug accidentally when playing around with Lua for an
add-on of mine. Invalid terrain (specifically, in this case, setting a terrain
that is of the form of something like "Asdf^asdf^asdf") will crash the Wesnoth
client on the latest trunk, at least for me. Obviously, errors in Lua code
shouldn't be able to interfere with the integrity of the game client itself.
Since I must provide reproducible evidence, here's a quick example of a
function that can crash Wesnoth (and should work by simply copying and pasting
it into a working [lua] tag):
[lua]
code = <<
function crash_wesnoth()
local crash_this_terrain = wesnoth.get_terrain(1, 1)
local crash_this_terrain = crash_this_terrain.."^Vhs".."^Vhs"
wesnoth.set_terrain(1, 1, crash_this_terrain)
end
crash_wesnoth()
>>
[/lua]
While malicious add-ons might possibly exist, it's more likely that a general
function can crash Wesnoth accidentally by simply not including a check for an
overlay terrain that may already exist on that particular hex before adding
another overlay terrain via Lua. Here's an example of a probably-more-innocent
function that can also crash Wesnoth:
function overlay_set(terrain_symbol, change_terrain)
for i, terrain in ipairs(change_terrain) do
local terrain_type = wesnoth.get_terrain(terrain[1], terrain[2])
local terrain_symbol = terrain_type..terrain_symbol
wesnoth.set_terrain(terrain[1], terrain[2], terrain_symbol)
end
end
change_terrain = wesnoth.get_locations({x = 14, y = 14, radius = 2})
overlay_set("^Vhs", change_terrain)
This code (or a slight variant of it) should crash Wesnoth if any of the
hexes in its radius have a terrain overlay (e.g. forest). I realize the proper
way to do this is to first check to see if there's any overlays and if there
are, to replace them instead of just append, but my point is that sloppy Lua
coding shouldn't be able to crash the Wesnoth client.
Sorry if my writing is a little incoherent (or if I made a typo in my Lua).
I'm tired and in a bit of a hurry, but I hope the code is clear and speaks for
itself. It is possible that there's a more general issue here with
wesnoth.set_terrain(), but this is just all I have had time to test for.
Thanks,
Aeth
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<http://gna.org/bugs/?17577>
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