slither.utils.arithmetic

 1from typing import List, TYPE_CHECKING
 2
 3from slither.exceptions import SlitherException
 4from slither.utils.integer_conversion import convert_string_to_fraction
 5
 6
 7if TYPE_CHECKING:
 8    from slither.core.declarations import Contract, Function
 9
10# pylint: disable=too-many-branches
11def convert_subdenomination(
12    value: str, sub: str
13) -> int:  # pylint: disable=too-many-return-statements
14
15    decimal_value = convert_string_to_fraction(value)
16    if sub == "wei":
17        return int(decimal_value)
18    if sub == "gwei":
19        return int(decimal_value * int(1e9))
20    if sub == "szabo":
21        return int(decimal_value * int(1e12))
22    if sub == "finney":
23        return int(decimal_value * int(1e15))
24    if sub == "ether":
25        return int(decimal_value * int(1e18))
26    if sub == "seconds":
27        return int(decimal_value)
28    if sub == "minutes":
29        return int(decimal_value * 60)
30    if sub == "hours":
31        return int(decimal_value * 60 * 60)
32    if sub == "days":
33        return int(decimal_value * 60 * 60 * 24)
34    if sub == "weeks":
35        return int(decimal_value * 60 * 60 * 24 * 7)
36    if sub == "years":
37        return int(decimal_value * 60 * 60 * 24 * 7 * 365)
38
39    raise SlitherException(f"Subdemonination conversion impossible {decimal_value} {sub}")
40
41
42# Number of unchecked arithmetic operation needed to be interesting
43THRESHOLD_ARITHMETIC_USAGE = 3
44
45
46def _unchecked_arithemtic_usage(function: "Function") -> bool:
47    """
48    Check if the function has more than THRESHOLD_ARITHMETIC_USAGE unchecked arithmetic operation
49
50    Args:
51        function:
52
53    Returns:
54
55    """
56
57    # pylint: disable=import-outside-toplevel
58    from slither.slithir.operations import Binary
59
60    score = 0
61    for node in function.nodes:
62        if not node.scope.is_checked:
63            for ir in node.irs:
64                if isinstance(ir, Binary):
65                    score += 1
66                    if score >= THRESHOLD_ARITHMETIC_USAGE:
67                        return True
68    return False
69
70
71def unchecked_arithemtic_usage(contract: "Contract") -> List["Function"]:
72    """
73    Return the list of function with some unchecked arithmetics
74
75    Args:
76        contract:
77
78    Returns:
79
80    """
81    # pylint: disable=import-outside-toplevel
82    from slither.core.declarations import Function
83
84    ret: List[Function] = []
85    for function in contract.all_functions_called:
86        if isinstance(function, Function) and _unchecked_arithemtic_usage(function):
87            ret.append(function)
88    return ret