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Detect integer overflow in rational_new_f().

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This commit is contained in:
Yukihiro "Matz" Matsumoto
2021-01-24 21:42:34 +09:00
parent 48b214f0b5
commit cc59860e40
1 changed files with 34 additions and 8 deletions
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mrbgems/mruby-rational/src/rational.c
+34 -8
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@@ -70,19 +70,36 @@ rational_denominator(mrb_state *mrb, mrb_value self)
return mrb_int_value(mrb, p->denominator);
}
static void
rat_overflow(mrb_state *mrb)
{
mrb_raise(mrb, E_RANGE_ERROR, "integer overflow in rational");
}
static void
rat_zerodiv(mrb_state *mrb)
{
mrb_raise(mrb, E_ZERODIV_ERROR, "divided by 0 in rational");
}
static mrb_value
rational_new(mrb_state *mrb, mrb_int numerator, mrb_int denominator)
{
struct RClass *c = mrb_class_get_id(mrb, MRB_SYM(Rational));
struct mrb_rational *p;
struct RBasic *rat = rational_alloc(mrb, c, &p);
struct RBasic *rat;
if (denominator == 0) {
rat_zerodiv(mrb);
}
if (denominator < 0) {
if (numerator == MRB_INT_MIN || denominator == MRB_INT_MIN) {
mrb_raise(mrb, E_RANGE_ERROR, "integer overflow in rational");
rat_overflow(mrb);
}
numerator *= -1;
denominator *= -1;
}
rat = rational_alloc(mrb, c, &p);
p->numerator = numerator;
p->denominator = denominator;
MRB_SET_FROZEN_FLAG(rat);
@@ -136,11 +153,11 @@ rational_new_i(mrb_state *mrb, mrb_int n, mrb_int d)
mrb_int a;
if (d == 0) {
mrb_raise(mrb, E_ZERODIV_ERROR, "divided by 0 in rational");
rat_zerodiv(mrb);
}
a = i_gcd(n, d);
if ((n == MRB_INT_MIN || d == MRB_INT_MIN) && a == -1) {
mrb_raise(mrb, E_RANGE_ERROR, "integer overflow in rational");
rat_overflow(mrb);
}
return rational_new(mrb, n/a, d/a);
}
@@ -152,12 +169,13 @@ rational_new_i(mrb_state *mrb, mrb_int n, mrb_int d)
#define frexp_rat frexpf
#define ldexp_rat ldexpf
#define RAT_MANT_DIG FLT_MANT_DIG
#define RAT_INT_LIMIT 30
#define RAT_HUGE_VAL HUGE_VALF
#else
#define frexp_rat frexp
#define ldexp_rat ldexp
#define RAT_MANT_DIG DBL_MANT_DIG
#define RAT_INT_LIMIT 62
#define RAT_HUGE_VAL HUGE_VAL
#endif
static void
@@ -182,10 +200,15 @@ rational_new_f(mrb_state *mrb, mrb_float f0)
#if FLT_RADIX == 2
if (n == 0)
return rational_new(mrb, (mrb_int)f, 1);
if (n > 0)
if (n > 0) {
f = ldexp_rat(f, n);
if (f == RAT_HUGE_VAL || f > (mrb_float)MRB_INT_MAX) {
rat_overflow(mrb);
}
return rational_new(mrb, ((mrb_int)f)<<n, 1);
}
if (n < -RAT_INT_LIMIT) {
f = ldexp(f, n+RAT_INT_LIMIT);
f = ldexp_rat(f, n+RAT_INT_LIMIT);
n = RAT_INT_LIMIT;
}
else {
@@ -207,6 +230,9 @@ rational_new_f(mrb_state *mrb, mrb_float f0)
}
else {
while (n--) {
if (MRB_INT_MAX/FLT_RADIX < pow) {
rat_overflow(mrb);
}
pow *= FLT_RADIX;
}
return rational_new(mrb, (mrb_int)f*pow, 1);
@@ -279,7 +305,7 @@ rational_to_i(mrb_state *mrb, mrb_value self)
{
struct mrb_rational *p = rational_ptr(mrb, self);
if (p->denominator == 0) {
mrb_raise(mrb, mrb->eStandardError_class, "divided by 0");
rat_zerodiv(mrb);
}
return mrb_int_value(mrb, p->numerator / p->denominator);
}