Language: C
Label: vulnerable
CWE: CWE-190 \u2014 Integer Overflow or Wraparound
The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control.

Code:
int bn_gen_prime_factor(bn_t a, bn_t b, int abits, int bbits) {
	bn_t t;
	int result = RLC_OK;

    if (! (bbits>abits) ) {
		return RLC_ERR;
    }

    bn_null(t);

    RLC_TRY {
        bn_new(t);
		bn_gen_prime(a, abits);
        do {
            bn_rand(t, RLC_POS, bbits - bn_bits(a));
            do {
                bn_mul(b, a, t);
                bn_add_dig(b, b, 1);
                bn_add_dig(t, t, 1);
            } while(! bn_is_prime(b));
        } while (bn_bits(b) != bbits);
    }
    RLC_CATCH_ANY {
		result = RLC_ERR;
    }
    RLC_FINALLY {
        bn_free(t);
    }

    return result;
}