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Initialization of too many locals break assertion

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The check for limit of local variables is made after generating code to
initialize them. If there are too many local variables not initialized,
the coding of instruction OP_LOADNIL could overflow an argument.
This commit is contained in:
Roberto I
2025-10-10 13:22:19 -03:00
parent 25c54fe60e
commit 3347c9d32d
2 changed files with 13 additions and 7 deletions
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1
lparser.c
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@@ -547,6 +547,7 @@ static void singlevar (LexState *ls, expdesc *var) {
static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) { static void adjust_assign (LexState *ls, int nvars, int nexps, expdesc *e) {
FuncState *fs = ls->fs; FuncState *fs = ls->fs;
int needed = nvars - nexps; /* extra values needed */ int needed = nvars - nexps; /* extra values needed */
luaK_checkstack(fs, needed);
if (hasmultret(e->k)) { /* last expression has multiple returns? */ if (hasmultret(e->k)) { /* last expression has multiple returns? */
int extra = needed + 1; /* discount last expression itself */ int extra = needed + 1; /* discount last expression itself */
if (extra < 0) if (extra < 0)

19
testes/errors.lua
View File

@@ -689,21 +689,26 @@ end
-- testing syntax limits -- testing syntax limits
local function testrep (init, rep, close, repc, finalresult) local function testrep (init, rep, close, repc, finalresult)
local s = init .. string.rep(rep, 100) .. close .. string.rep(repc, 100) local function gencode (n)
local res, msg = load(s) return init .. string.rep(rep, n) .. close .. string.rep(repc, n)
assert(res) -- 100 levels is OK end
local res, msg = load(gencode(100)) -- 100 levels is OK
assert(res)
if (finalresult) then if (finalresult) then
assert(res() == finalresult) assert(res() == finalresult)
end end
s = init .. string.rep(rep, 500) local res, msg = load(gencode(500)) -- 500 levels not ok
local res, msg = load(s) -- 500 levels not ok
assert(not res and (string.find(msg, "too many") or assert(not res and (string.find(msg, "too many") or
string.find(msg, "overflow"))) string.find(msg, "overflow")))
end end
testrep("local a", ",a", ";", "") -- local variables
testrep("local a", ",a", "= 1", ",1") -- local variables initialized
testrep("local a", ",a", "= f()", "") -- local variables initialized
testrep("local a; a", ",a", "= 1", ",1") -- multiple assignment testrep("local a; a", ",a", "= 1", ",1") -- multiple assignment
testrep("local a; a=", "{", "0", "}") testrep("local a; a=", "{", "0", "}") -- constructors
testrep("return ", "(", "2", ")", 2) testrep("return ", "(", "2", ")", 2) -- parentheses
-- nested calls (a(a(a(a(...)))))
testrep("local function a (x) return x end; return ", "a(", "2.2", ")", 2.2) testrep("local function a (x) return x end; return ", "a(", "2.2", ")", 2.2)
testrep("", "do ", "", " end") testrep("", "do ", "", " end")
testrep("", "while a do ", "", " end") testrep("", "while a do ", "", " end")