Handle partial snapshot restore due to stack overflow.

Reported by pwnhacker0x18. Fixed by Peter Cawley. #1196
This commit is contained in:
Mike Pall
2024-07-03 21:42:21 +02:00
parent 4a22050df9
commit 811c5322c8
2 changed files with 9 additions and 4 deletions

View File

@@ -102,9 +102,12 @@ static BCPos debug_framepc(lua_State *L, GCfunc *fn, cTValue *nextframe)
pos = proto_bcpos(pt, ins) - 1;
#if LJ_HASJIT
if (pos > pt->sizebc) { /* Undo the effects of lj_trace_exit for JLOOP. */
GCtrace *T = (GCtrace *)((char *)(ins-1) - offsetof(GCtrace, startins));
lua_assert(bc_isret(bc_op(ins[-1])));
pos = proto_bcpos(pt, mref(T->startpc, const BCIns));
if (bc_isret(bc_op(ins[-1]))) {
GCtrace *T = (GCtrace *)((char *)(ins-1) - offsetof(GCtrace, startins));
pos = proto_bcpos(pt, mref(T->startpc, const BCIns));
} else {
pos = NO_BCPOS; /* Punt in case of stack overflow. */
}
}
#endif
return pos;