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Avoid computing invalid addresses 

luaV_execute should compute 'ra' only when the instruction uses it.
Computing an illegal address is undefined behavior even if the address
is never dereferenced.
pull/27/head
Roberto Ierusalimschy 3 years ago
parent
1f3c6f4534
commit
8426d9b4d4
1 changed files with 89 additions and 32 deletions
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  1. 69
      lvm.c

69
lvm.c
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@ -898,6 +898,7 @@ void luaV_finishOp (lua_State *L) {
** operation, 'fop' is the float operation.
*/
#define op_arithI(L,iop,fop) { \
StkId ra = RA(i); \
TValue *v1 = vRB(i); \
int imm = GETARG_sC(i); \
if (ttisinteger(v1)) { \
@ -926,6 +927,7 @@ void luaV_finishOp (lua_State *L) {
** Arithmetic operations over floats and others with register operands.
*/
#define op_arithf(L,fop) { \
StkId ra = RA(i); \
TValue *v1 = vRB(i); \
TValue *v2 = vRC(i); \
op_arithf_aux(L, v1, v2, fop); }
@ -935,6 +937,7 @@ void luaV_finishOp (lua_State *L) {
** Arithmetic operations with K operands for floats.
*/
#define op_arithfK(L,fop) { \
StkId ra = RA(i); \
TValue *v1 = vRB(i); \
TValue *v2 = KC(i); lua_assert(ttisnumber(v2)); \
op_arithf_aux(L, v1, v2, fop); }
@ -944,6 +947,7 @@ void luaV_finishOp (lua_State *L) {
** Arithmetic operations over integers and floats.
*/
#define op_arith_aux(L,v1,v2,iop,fop) { \
StkId ra = RA(i); \
if (ttisinteger(v1) && ttisinteger(v2)) { \
lua_Integer i1 = ivalue(v1); lua_Integer i2 = ivalue(v2); \
pc++; setivalue(s2v(ra), iop(L, i1, i2)); \
@ -973,6 +977,7 @@ void luaV_finishOp (lua_State *L) {
** Bitwise operations with constant operand.
*/
#define op_bitwiseK(L,op) { \
StkId ra = RA(i); \
TValue *v1 = vRB(i); \
TValue *v2 = KC(i); \
lua_Integer i1; \
@ -986,6 +991,7 @@ void luaV_finishOp (lua_State *L) {
** Bitwise operations with register operands.
*/
#define op_bitwise(L,op) { \
StkId ra = RA(i); \
TValue *v1 = vRB(i); \
TValue *v2 = vRC(i); \
lua_Integer i1; lua_Integer i2; \
@ -1000,6 +1006,7 @@ void luaV_finishOp (lua_State *L) {
** integers.
*/
#define op_order(L,opi,opn,other) { \
StkId ra = RA(i); \
int cond; \
TValue *rb = vRB(i); \
if (ttisinteger(s2v(ra)) && ttisinteger(rb)) { \
@ -1019,6 +1026,7 @@ void luaV_finishOp (lua_State *L) {
** always small enough to have an exact representation as a float.)
*/
#define op_orderI(L,opi,opf,inv,tm) { \
StkId ra = RA(i); \
int cond; \
int im = GETARG_sB(i); \
if (ttisinteger(s2v(ra))) \
@ -1128,7 +1136,6 @@ void luaV_finishOp (lua_State *L) {
updatebase(ci); /* correct stack */ \
} \
i = *(pc++); \
ra = RA(i); /* WARNING: any stack reallocation invalidates 'ra' */ \
}
#define vmdispatch(o) switch(o)
@ -1164,7 +1171,6 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
/* main loop of interpreter */
for (;;) {
Instruction i; /* instruction being executed */
StkId ra; /* instruction's A register */
vmfetch();
#if 0
/* low-level line tracing for debugging Lua */
@ -1176,44 +1182,53 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
lua_assert(isIT(i) || (cast_void(L->top = base), 1));
vmdispatch (GET_OPCODE(i)) {
vmcase(OP_MOVE) {
StkId ra = RA(i);
setobjs2s(L, ra, RB(i));
vmbreak;
}
vmcase(OP_LOADI) {
StkId ra = RA(i);
lua_Integer b = GETARG_sBx(i);
setivalue(s2v(ra), b);
vmbreak;
}
vmcase(OP_LOADF) {
StkId ra = RA(i);
int b = GETARG_sBx(i);
setfltvalue(s2v(ra), cast_num(b));
vmbreak;
}
vmcase(OP_LOADK) {
StkId ra = RA(i);
TValue *rb = k + GETARG_Bx(i);
setobj2s(L, ra, rb);
vmbreak;
}
vmcase(OP_LOADKX) {
StkId ra = RA(i);
TValue *rb;
rb = k + GETARG_Ax(*pc); pc++;
setobj2s(L, ra, rb);
vmbreak;
}
vmcase(OP_LOADFALSE) {
StkId ra = RA(i);
setbfvalue(s2v(ra));
vmbreak;
}
vmcase(OP_LFALSESKIP) {
StkId ra = RA(i);
setbfvalue(s2v(ra));
pc++; /* skip next instruction */
vmbreak;
}
vmcase(OP_LOADTRUE) {
StkId ra = RA(i);
setbtvalue(s2v(ra));
vmbreak;
}
vmcase(OP_LOADNIL) {
StkId ra = RA(i);
int b = GETARG_B(i);
do {
setnilvalue(s2v(ra++));
@ -1221,17 +1236,20 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_GETUPVAL) {
StkId ra = RA(i);
int b = GETARG_B(i);
setobj2s(L, ra, cl->upvals[b]->v);
vmbreak;
}
vmcase(OP_SETUPVAL) {
StkId ra = RA(i);
UpVal *uv = cl->upvals[GETARG_B(i)];
setobj(L, uv->v, s2v(ra));
luaC_barrier(L, uv, s2v(ra));
vmbreak;
}
vmcase(OP_GETTABUP) {
StkId ra = RA(i);
const TValue *slot;
TValue *upval = cl->upvals[GETARG_B(i)]->v;
TValue *rc = KC(i);
@ -1244,6 +1262,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_GETTABLE) {
StkId ra = RA(i);
const TValue *slot;
TValue *rb = vRB(i);
TValue *rc = vRC(i);
@ -1258,6 +1277,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_GETI) {
StkId ra = RA(i);
const TValue *slot;
TValue *rb = vRB(i);
int c = GETARG_C(i);
@ -1272,6 +1292,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_GETFIELD) {
StkId ra = RA(i);
const TValue *slot;
TValue *rb = vRB(i);
TValue *rc = KC(i);
@ -1297,6 +1318,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_SETTABLE) {
StkId ra = RA(i);
const TValue *slot;
TValue *rb = vRB(i); /* key (table is in 'ra') */
TValue *rc = RKC(i); /* value */
@ -1311,6 +1333,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_SETI) {
StkId ra = RA(i);
const TValue *slot;
int c = GETARG_B(i);
TValue *rc = RKC(i);
@ -1325,6 +1348,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_SETFIELD) {
StkId ra = RA(i);
const TValue *slot;
TValue *rb = KB(i);
TValue *rc = RKC(i);
@ -1337,6 +1361,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_NEWTABLE) {
StkId ra = RA(i);
int b = GETARG_B(i); /* log2(hash size) + 1 */
int c = GETARG_C(i); /* array size */
Table *t;
@ -1355,6 +1380,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_SELF) {
StkId ra = RA(i);
const TValue *slot;
TValue *rb = vRB(i);
TValue *rc = RKC(i);
@ -1412,6 +1438,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_SHRI) {
StkId ra = RA(i);
TValue *rb = vRB(i);
int ic = GETARG_sC(i);
lua_Integer ib;
@ -1421,6 +1448,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_SHLI) {
StkId ra = RA(i);
TValue *rb = vRB(i);
int ic = GETARG_sC(i);
lua_Integer ib;
@ -1478,6 +1506,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_MMBIN) {
StkId ra = RA(i);
Instruction pi = *(pc - 2); /* original arith. expression */
TValue *rb = vRB(i);
TMS tm = (TMS)GETARG_C(i);
@ -1487,6 +1516,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_MMBINI) {
StkId ra = RA(i);
Instruction pi = *(pc - 2); /* original arith. expression */
int imm = GETARG_sB(i);
TMS tm = (TMS)GETARG_C(i);
@ -1496,6 +1526,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_MMBINK) {
StkId ra = RA(i);
Instruction pi = *(pc - 2); /* original arith. expression */
TValue *imm = KB(i);
TMS tm = (TMS)GETARG_C(i);
@ -1505,6 +1536,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_UNM) {
StkId ra = RA(i);
TValue *rb = vRB(i);
lua_Number nb;
if (ttisinteger(rb)) {
@ -1519,6 +1551,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_BNOT) {
StkId ra = RA(i);
TValue *rb = vRB(i);
lua_Integer ib;
if (tointegerns(rb, &ib)) {
@ -1529,6 +1562,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_NOT) {
StkId ra = RA(i);
TValue *rb = vRB(i);
if (l_isfalse(rb))
setbtvalue(s2v(ra));
@ -1537,10 +1571,12 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_LEN) {
StkId ra = RA(i);
Protect(luaV_objlen(L, ra, vRB(i)));
vmbreak;
}
vmcase(OP_CONCAT) {
StkId ra = RA(i);
int n = GETARG_B(i); /* number of elements to concatenate */
L->top = ra + n; /* mark the end of concat operands */
ProtectNT(luaV_concat(L, n));
@ -1548,10 +1584,12 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_CLOSE) {
StkId ra = RA(i);
Protect(luaF_close(L, ra, LUA_OK, 1));
vmbreak;
}
vmcase(OP_TBC) {
StkId ra = RA(i);
/* create new to-be-closed upvalue */
halfProtect(luaF_newtbcupval(L, ra));
vmbreak;
@ -1561,6 +1599,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_EQ) {
StkId ra = RA(i);
int cond;
TValue *rb = vRB(i);
Protect(cond = luaV_equalobj(L, s2v(ra), rb));
@ -1576,6 +1615,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_EQK) {
StkId ra = RA(i);
TValue *rb = KB(i);
/* basic types do not use '__eq'; we can use raw equality */
int cond = luaV_rawequalobj(s2v(ra), rb);
@ -1583,6 +1623,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_EQI) {
StkId ra = RA(i);
int cond;
int im = GETARG_sB(i);
if (ttisinteger(s2v(ra)))
@ -1611,11 +1652,13 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_TEST) {
StkId ra = RA(i);
int cond = !l_isfalse(s2v(ra));
docondjump();
vmbreak;
}
vmcase(OP_TESTSET) {
StkId ra = RA(i);
TValue *rb = vRB(i);
if (l_isfalse(rb) == GETARG_k(i))
pc++;
@ -1626,6 +1669,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_CALL) {
StkId ra = RA(i);
CallInfo *newci;
int b = GETARG_B(i);
int nresults = GETARG_C(i) - 1;
@ -1642,6 +1686,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_TAILCALL) {
StkId ra = RA(i);
int b = GETARG_B(i); /* number of arguments + 1 (function) */
int n; /* number of results when calling a C function */
int nparams1 = GETARG_C(i);
@ -1667,6 +1712,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
}
}
vmcase(OP_RETURN) {
StkId ra = RA(i);
int n = GETARG_B(i) - 1; /* number of results */
int nparams1 = GETARG_C(i);
if (n < 0) /* not fixed? */
@ -1689,6 +1735,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
}
vmcase(OP_RETURN0) {
if (l_unlikely(L->hookmask)) {
StkId ra = RA(i);
L->top = ra;
savepc(ci);
luaD_poscall(L, ci, 0); /* no hurry... */
@ -1705,6 +1752,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
}
vmcase(OP_RETURN1) {
if (l_unlikely(L->hookmask)) {
StkId ra = RA(i);
L->top = ra + 1;
savepc(ci);
luaD_poscall(L, ci, 1); /* no hurry... */
@ -1716,6 +1764,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
if (nres == 0)
L->top = base - 1; /* asked for no results */
else {
StkId ra = RA(i);
setobjs2s(L, base - 1, ra); /* at least this result */
L->top = base;
for (; l_unlikely(nres > 1); nres--)
@ -1731,6 +1780,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
}
}
vmcase(OP_FORLOOP) {
StkId ra = RA(i);
if (ttisinteger(s2v(ra + 2))) { /* integer loop? */
lua_Unsigned count = l_castS2U(ivalue(s2v(ra + 1)));
if (count > 0) { /* still more iterations? */
@ -1749,12 +1799,14 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_FORPREP) {
StkId ra = RA(i);
savestate(L, ci); /* in case of errors */
if (forprep(L, ra))
pc += GETARG_Bx(i) + 1; /* skip the loop */
vmbreak;
}
vmcase(OP_TFORPREP) {
StkId ra = RA(i);
/* create to-be-closed upvalue (if needed) */
halfProtect(luaF_newtbcupval(L, ra + 3));
pc += GETARG_Bx(i);
@ -1763,7 +1815,8 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
goto l_tforcall;
}
vmcase(OP_TFORCALL) {
l_tforcall:
l_tforcall: {
StkId ra = RA(i);
/* 'ra' has the iterator function, 'ra + 1' has the state,
'ra + 2' has the control variable, and 'ra + 3' has the
to-be-closed variable. The call will use the stack after
@ -1777,16 +1830,18 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
i = *(pc++); /* go to next instruction */
lua_assert(GET_OPCODE(i) == OP_TFORLOOP && ra == RA(i));
goto l_tforloop;
}
}}
vmcase(OP_TFORLOOP) {
l_tforloop:
l_tforloop: {
StkId ra = RA(i);
if (!ttisnil(s2v(ra + 4))) { /* continue loop? */
setobjs2s(L, ra + 2, ra + 4); /* save control variable */
pc -= GETARG_Bx(i); /* jump back */
}
vmbreak;
}
}}
vmcase(OP_SETLIST) {
StkId ra = RA(i);
int n = GETARG_B(i);
unsigned int last = GETARG_C(i);
Table *h = hvalue(s2v(ra));
@ -1810,12 +1865,14 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
vmbreak;
}
vmcase(OP_CLOSURE) {
StkId ra = RA(i);
Proto *p = cl->p->p[GETARG_Bx(i)];
halfProtect(pushclosure(L, p, cl->upvals, base, ra));
checkGC(L, ra + 1);
vmbreak;
}
vmcase(OP_VARARG) {
StkId ra = RA(i);
int n = GETARG_C(i) - 1; /* required results */
Protect(luaT_getvarargs(L, ci, ra, n));
vmbreak;

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