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Where possible, don't call to_lua / from_lua / to_lua_multi / from_lua_multi callbacks during Lua stack manipulation

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This should protect against being able to trigger a stack assert in Lua.  Lua
and associated types shoul be able to assume that LUA_MINSTACK stack slots are
available on any user entry point.  In the future, we could turn check_stack
into something that only checked the Lua stack when debug_assertions is true.
This commit is contained in:
kyren 2018-03-19 15:16:40 -04:00
parent 0d5e45e800
commit a05f0d5cd0
5 changed files with 114 additions and 82 deletions
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7
src/function.rs
View file

@ -67,7 +67,7 @@ impl<'lua> Function<'lua> {
let args = args.to_lua_multi(lua)?;
let nargs = args.len() as c_int;
unsafe {
let results = unsafe {
let _sg = StackGuard::new(lua.state);
check_stack_err(lua.state, nargs + 3)?;
@ -88,8 +88,9 @@ impl<'lua> Function<'lua> {
results.push_front(lua.pop_value());
}
ffi::lua_pop(lua.state, 1);
R::from_lua_multi(results, lua)
}
results
};
R::from_lua_multi(results, lua)
}
/// Returns a function that, when called, calls `self`, passing `args` as the first set of

24
src/lua.rs
View file

@ -184,7 +184,9 @@ impl Lua {
{
unsafe {
let _sg = StackGuard::new(self.state);
check_stack(self.state, 5);
// `Lua` instance assumes that on any callback, the Lua stack has at least LUA_MINSTACK
// slots available to avoid panics.
check_stack_err(self.state, 5 + ffi::LUA_MINSTACK)?;
unsafe extern "C" fn new_table(state: *mut ffi::lua_State) -> c_int {
ffi::lua_newtable(state);
@ -479,12 +481,13 @@ impl Lua {
name: &str,
t: T,
) -> Result<()> {
let t = t.to_lua(self)?;
unsafe {
let _sg = StackGuard::new(self.state);
check_stack(self.state, 5);
push_string(self.state, name)?;
self.push_value(t.to_lua(self)?);
self.push_value(t);
unsafe extern "C" fn set_registry(state: *mut ffi::lua_State) -> c_int {
ffi::lua_rawset(state, ffi::LUA_REGISTRYINDEX);
@ -501,7 +504,7 @@ impl Lua {
///
/// [`set_named_registry_value`]: #method.set_named_registry_value
pub fn named_registry_value<'lua, T: FromLua<'lua>>(&'lua self, name: &str) -> Result<T> {
unsafe {
let value = unsafe {
let _sg = StackGuard::new(self.state);
check_stack(self.state, 4);
@ -512,8 +515,9 @@ impl Lua {
}
protect_lua(self.state, 1, get_registry)?;
T::from_lua(self.pop_value(), self)
}
self.pop_value()
};
T::from_lua(value, self)
}
/// Removes a named value in the Lua registry.
@ -530,11 +534,12 @@ impl Lua {
/// This value will be available to rust from all `Lua` instances which share the same main
/// state.
pub fn create_registry_value<'lua, T: ToLua<'lua>>(&'lua self, t: T) -> Result<RegistryKey> {
let t = t.to_lua(self)?;
unsafe {
let _sg = StackGuard::new(self.state);
check_stack(self.state, 2);
self.push_value(t.to_lua(self)?);
self.push_value(t);
let registry_id = gc_guard(self.state, || {
ffi::luaL_ref(self.state, ffi::LUA_REGISTRYINDEX)
});
@ -553,7 +558,7 @@ impl Lua {
///
/// [`create_registry_value`]: #method.create_registry_value
pub fn registry_value<'lua, T: FromLua<'lua>>(&'lua self, key: &RegistryKey) -> Result<T> {
unsafe {
let value = unsafe {
if !self.owns_registry_value(key) {
return Err(Error::MismatchedRegistryKey);
}
@ -566,8 +571,9 @@ impl Lua {
ffi::LUA_REGISTRYINDEX,
key.registry_id as ffi::lua_Integer,
);
T::from_lua(self.pop_value(), self)
}
self.pop_value()
};
T::from_lua(value, self)
}
/// Removes a value from the Lua registry.

91
src/table.rs
View file

@ -51,13 +51,15 @@ impl<'lua> Table<'lua> {
/// [`raw_set`]: #method.raw_set
pub fn set<K: ToLua<'lua>, V: ToLua<'lua>>(&self, key: K, value: V) -> Result<()> {
let lua = self.0.lua;
let key = key.to_lua(lua)?;
let value = value.to_lua(lua)?;
unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 6);
lua.push_ref(&self.0);
lua.push_value(key.to_lua(lua)?);
lua.push_value(value.to_lua(lua)?);
lua.push_value(key);
lua.push_value(value);
unsafe extern "C" fn set_table(state: *mut ffi::lua_State) -> c_int {
ffi::lua_settable(state, -3);
@ -97,32 +99,35 @@ impl<'lua> Table<'lua> {
/// [`raw_get`]: #method.raw_get
pub fn get<K: ToLua<'lua>, V: FromLua<'lua>>(&self, key: K) -> Result<V> {
let lua = self.0.lua;
unsafe {
let key = key.to_lua(lua)?;
let value = unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 5);
lua.push_ref(&self.0);
lua.push_value(key.to_lua(lua)?);
lua.push_value(key);
unsafe extern "C" fn get_table(state: *mut ffi::lua_State) -> c_int {
ffi::lua_gettable(state, -2);
1
}
protect_lua(lua.state, 2, get_table)?;
V::from_lua(lua.pop_value(), lua)
}
lua.pop_value()
};
V::from_lua(value, lua)
}
/// Checks whether the table contains a non-nil value for `key`.
pub fn contains_key<K: ToLua<'lua>>(&self, key: K) -> Result<bool> {
let lua = self.0.lua;
let key = key.to_lua(lua)?;
unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 5);
lua.push_ref(&self.0);
lua.push_value(key.to_lua(lua)?);
lua.push_value(key);
unsafe extern "C" fn get_table(state: *mut ffi::lua_State) -> c_int {
ffi::lua_gettable(state, -2);
@ -138,13 +143,16 @@ impl<'lua> Table<'lua> {
/// Sets a key-value pair without invoking metamethods.
pub fn raw_set<K: ToLua<'lua>, V: ToLua<'lua>>(&self, key: K, value: V) -> Result<()> {
let lua = self.0.lua;
let key = key.to_lua(lua)?;
let value = value.to_lua(lua)?;
unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 6);
lua.push_ref(&self.0);
lua.push_value(key.to_lua(lua)?);
lua.push_value(value.to_lua(lua)?);
lua.push_value(key);
lua.push_value(value);
unsafe extern "C" fn raw_set(state: *mut ffi::lua_State) -> c_int {
ffi::lua_rawset(state, -3);
@ -159,16 +167,17 @@ impl<'lua> Table<'lua> {
/// Gets the value associated to `key` without invoking metamethods.
pub fn raw_get<K: ToLua<'lua>, V: FromLua<'lua>>(&self, key: K) -> Result<V> {
let lua = self.0.lua;
unsafe {
let key = key.to_lua(lua)?;
let value = unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 3);
lua.push_ref(&self.0);
lua.push_value(key.to_lua(lua)?);
lua.push_value(key);
ffi::lua_rawget(lua.state, -2);
let res = V::from_lua(lua.pop_value(), lua)?;
Ok(res)
}
lua.pop_value()
};
V::from_lua(value, lua)
}
/// Returns the result of the Lua `#` operator.
@ -354,31 +363,39 @@ where
if let Some(next_key) = self.next_key.take() {
let lua = self.table.lua;
unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 6);
let res = (|| {
let res = unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 6);
lua.push_ref(&self.table);
lua.push_ref(&next_key);
lua.push_ref(&self.table);
lua.push_ref(&next_key);
match protect_lua_closure(lua.state, 2, ffi::LUA_MULTRET, |state| {
ffi::lua_next(state, -2) != 0
}) {
Ok(false) => None,
Ok(true) => {
if protect_lua_closure(lua.state, 2, ffi::LUA_MULTRET, |state| {
ffi::lua_next(state, -2) != 0
})? {
ffi::lua_pushvalue(lua.state, -2);
let key = lua.pop_value();
let value = lua.pop_value();
self.next_key = Some(lua.pop_ref());
Some((|| {
let key = K::from_lua(key, lua)?;
let value = V::from_lua(value, lua)?;
Ok((key, value))
})())
Some((key, value))
} else {
None
}
Err(e) => Some(Err(e)),
}
};
Ok(if let Some((key, value)) = res {
Some((K::from_lua(key, lua)?, V::from_lua(value, lua)?))
} else {
None
})
})();
match res {
Ok(Some((key, value))) => Some(Ok((key, value))),
Ok(None) => None,
Err(e) => Some(Err(e)),
}
} else {
None
@ -407,7 +424,7 @@ where
if let Some(index) = self.index.take() {
let lua = self.table.lua;
unsafe {
let res = unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 5);
@ -418,10 +435,16 @@ where
Ok(_) => {
let value = lua.pop_value();
self.index = Some(index + 1);
Some(V::from_lua(value, lua))
Some(Ok(value))
}
Err(err) => Some(Err(err)),
}
};
match res {
Some(Ok(r)) => Some(V::from_lua(r, lua)),
Some(Err(err)) => Some(Err(err)),
None => None,
}
} else {
None

9
src/thread.rs
View file

@ -77,7 +77,8 @@ impl<'lua> Thread<'lua> {
R: FromLuaMulti<'lua>,
{
let lua = self.0.lua;
unsafe {
let args = args.to_lua_multi(lua)?;
let results = unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 1);
@ -91,7 +92,6 @@ impl<'lua> Thread<'lua> {
ffi::lua_pop(lua.state, 1);
let args = args.to_lua_multi(lua)?;
let nargs = args.len() as c_int;
check_stack_err(lua.state, nargs)?;
check_stack_err(thread_state, nargs + 1)?;
@ -115,8 +115,9 @@ impl<'lua> Thread<'lua> {
for _ in 0..nresults {
results.push_front(lua.pop_value());
}
R::from_lua_multi(results, lua)
}
results
};
R::from_lua_multi(results, lua)
}
/// Gets the status of the thread.

65
src/userdata.rs
View file

@ -408,6 +408,39 @@ impl<'lua> AnyUserData<'lua> {
})
}
/// Sets an associated value to this `AnyUserData`.
///
/// The value may be any Lua value whatsoever, and can be retrieved with [`get_user_value`].
///
/// [`get_user_value`]: #method.get_user_value
pub fn set_user_value<V: ToLua<'lua>>(&self, v: V) -> Result<()> {
let lua = self.0.lua;
let v = v.to_lua(lua)?;
unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 2);
lua.push_ref(&self.0);
lua.push_value(v);
ffi::lua_setuservalue(lua.state, -2);
Ok(())
}
}
/// Returns an associated value set by [`set_user_value`].
///
/// [`set_user_value`]: #method.set_user_value
pub fn get_user_value<V: FromLua<'lua>>(&self) -> Result<V> {
let lua = self.0.lua;
let res = unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 3);
lua.push_ref(&self.0);
ffi::lua_getuservalue(lua.state, -1);
lua.pop_value()
};
V::from_lua(res, lua)
}
fn inspect<'a, T, R, F>(&'a self, func: F) -> Result<R>
where
T: UserData,
@ -437,36 +470,4 @@ impl<'lua> AnyUserData<'lua> {
}
}
}
/// Sets an associated value to this `AnyUserData`.
///
/// The value may be any Lua value whatsoever, and can be retrieved with [`get_user_value`].
///
/// [`get_user_value`]: #method.get_user_value
pub fn set_user_value<V: ToLua<'lua>>(&self, v: V) -> Result<()> {
let lua = self.0.lua;
unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 2);
lua.push_ref(&self.0);
lua.push_value(v.to_lua(lua)?);
ffi::lua_setuservalue(lua.state, -2);
Ok(())
}
}
/// Returns an associated value set by [`set_user_value`].
///
/// [`set_user_value`]: #method.set_user_value
pub fn get_user_value<V: FromLua<'lua>>(&self) -> Result<V> {
let lua = self.0.lua;
unsafe {
let _sg = StackGuard::new(lua.state);
check_stack(lua.state, 3);
lua.push_ref(&self.0);
ffi::lua_getuservalue(lua.state, -1);
let res = V::from_lua(lua.pop_value(), lua)?;
Ok(res)
}
}
}