TonBERRY/micropython
3
0
Fork 0
Code Pull Requests Activity

py/objint_mpz: Fix pow3 where third argument is zero.

Browse Source 
This finding is based on fuzzing MicroPython.  I manually minimized the
test case it provided.

Signed-off-by: Jeff Epler <jepler@gmail.com>
This commit is contained in:
Jeff Epler
2025-07-19 11:24:34 -05:00
committed by Damien George
parent ebc9525c95
commit 062e82a7cd
2 changed files with 9 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
py/objint_mpz.c
View File

@@ -356,9 +356,10 @@ static mpz_t *mp_mpz_for_int(mp_obj_t arg, mpz_t *temp) {
mp_obj_t mp_obj_int_pow3(mp_obj_t base, mp_obj_t exponent, mp_obj_t modulus) { mp_obj_t mp_obj_int_pow3(mp_obj_t base, mp_obj_t exponent, mp_obj_t modulus) {
if (!mp_obj_is_int(base) || !mp_obj_is_int(exponent) || !mp_obj_is_int(modulus)) { if (!mp_obj_is_int(base) || !mp_obj_is_int(exponent) || !mp_obj_is_int(modulus)) {
mp_raise_TypeError(MP_ERROR_TEXT("pow() with 3 arguments requires integers")); mp_raise_TypeError(MP_ERROR_TEXT("pow() with 3 arguments requires integers"));
} else if (modulus == MP_OBJ_NEW_SMALL_INT(0)) {
mp_raise_ValueError(MP_ERROR_TEXT("divide by zero"));
} else { } else {
mp_obj_t result = mp_obj_new_int_from_ull(0); // Use the _from_ull version as this forces an mpz int mp_obj_int_t *res_p = mp_obj_int_new_mpz();
mp_obj_int_t *res_p = (mp_obj_int_t *)MP_OBJ_TO_PTR(result);
mpz_t l_temp, r_temp, m_temp; mpz_t l_temp, r_temp, m_temp;
mpz_t *lhs = mp_mpz_for_int(base, &l_temp); mpz_t *lhs = mp_mpz_for_int(base, &l_temp);
@@ -376,7 +377,7 @@ mp_obj_t mp_obj_int_pow3(mp_obj_t base, mp_obj_t exponent, mp_obj_t modulus) {
if (mod == &m_temp) { if (mod == &m_temp) {
mpz_deinit(mod); mpz_deinit(mod);
} }
return result; return MP_OBJ_FROM_PTR(res_p);
} }
} }
#endif #endif

5
tests/basics/builtin_pow3_intbig.py
View File

@@ -20,3 +20,8 @@ print(hex(pow(2, x-1, x))) # Should be 1, since x is prime
print(hex(pow(y, x-1, x))) # Should be 1, since x is prime print(hex(pow(y, x-1, x))) # Should be 1, since x is prime
print(hex(pow(y, y-1, x))) # Should be a 'big value' print(hex(pow(y, y-1, x))) # Should be a 'big value'
print(hex(pow(y, y-1, y))) # Should be a 'big value' print(hex(pow(y, y-1, y))) # Should be a 'big value'
try:
print(pow(1, 2, 0))
except ValueError:
print("ValueError")