CWE-665¶

Improper Initialization. [Improper-Control-Of-A-Resource-Through-Its-Lifetime]

Required inputs: IR, StaticSemanticAnalysis

The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used. This can have security implications when the associated resource is expected to have certain properties or values, such as a variable that determines whether a user has been authenticated or not.

Demonstrative Examples

Example 1

Here, a boolean initialized field is consulted to ensure that initialization tasks are only completed once. However, the field is mistakenly set to true during static initialization, so the initialization code is never reached.

Example Language:Java (Unsupported language for documentation only)
    private boolean initialized = true;
    public void someMethod() {
        if (!initialized) {
            // perform initialization tasks
            ...

            initialized = true;
        }

Example 2

The following code intends to limit certain operations to the administrator only.

Example Language:Perl (Unsupported language for documentation only)
    $username = GetCurrentUser();
    $state = GetStateData($username);
    if (defined($state)) {
        $uid = ExtractUserID($state);
    }

    # do stuff
    if ($uid == 0) {
        DoAdminThings();
    }

If the application is unable to extract the state information - say, due to a database timeout - then the $uid variable will not be explicitly set by the programmer. This will cause $uid to be regarded as equivalent to "0" in the conditional, allowing the original user to perform administrator actions. Even if the attacker cannot directly influence the state data, unexpected errors could cause incorrect privileges to be assigned to a user just by accident.

Example 3

The following code intends to concatenate a string to a variable and print the string.

Example Language:C
    char str[20];
    strcat(str, "hello world");
    printf("%s", str);

This might seem innocent enough, but str was not initialized, so it contains random memory. As a result, str[0] might not contain the null terminator, so the copy might start at an offset other than 0. The consequences can vary, depending on the underlying memory.

If a null terminator is found before str[8], then some bytes of random garbage will be printed before the "hello world" string. The memory might contain sensitive information from previous uses, such as a password (which might occur as a result of CWE-14 or CWE-244). In this example, it might not be a big deal, but consider what could happen if large amounts of memory are printed out before the null terminator is found.

If a null terminator isn't found before str[8], then a buffer overflow could occur, since strcat will first look for the null terminator, then copy 12 bytes starting with that location. Alternately, a buffer over-read might occur (CWE-126) if a null terminator isn't found before the end of the memory segment is reached, leading to a segmentation fault and crash.

Possible Messages

Key	Text	Severity	Disabled
assigned_to_pointer_to_const	Assigning the address of a partially initialized variable to some pointer-to-const	None	False
pass_as_pointer_to_const_param	Passing uninitialized variable by pointer as function parameter with pointer-to-const type	None	False
possible_invalid_call_argument	Call to {} with string buffer argument {} that possibly has no valid null delimiter character.	None	False
possible_return_value_uninit	Function return value is potentially not initialized	None	False
possible_uninit	Use of possibly uninitialized variable	None	False
possibly_initialized	Use of possibly uninitialized variable (previous call {node0} might have initialized the variable)	None	False
return_value_uninit	Function return value is not initialized	None	False
uninit	Use of uninitialized variable	None	False

Options¶

This rule shares the following common options: exclude_in_macros, exclude_messages_in_system_headers, excludes, extend_exclude_to_macro_invocations, includes, justification_checker, languages, post_processing, provider, report_at, severity
The following places define options that affect this rule: Stylechecks, Analysis-GlobalOptions

additional_local_array_check¶

additional_local_array_check : bool = True

Invoke an additional analysis that tries to remove false positives involving accesses to local array variables and in particular their initialization. The analysis attempts to report only the first use of an uninitialized value. Consider e.g. the following example:

    int example()
    {
        int a[10];
        int b[20];
        int uninit_var;
        for (int i = 0; i < 10; ++i)
        {
L1:         a[i] = uninit_var; // use of uninit_var reported
            b[i] = i;
        }
        int result = a[3]; // not reported, since already reported at L1
        result += b[15]; // reported; c[] is not (completely) initialized
        return result;
    }

assume_globals_are_initialized¶

assume_globals_are_initialized : bool = True

Whether global and local static variables should be treated as initialized (as specified by the language).

check_array_access_with_unknown_index¶

check_array_access_with_unknown_index : bool = False

Whether array accesses like a[i] with non-literal index i should be checked as well.

concat_operations¶

concat_operations

Type: dict[bauhaus.analysis.config.QualifiedName, typing.Tuple[int, int]]

Default:
{
   'strcat': (0, 1)
}

Names of buffer-concatenating functions being relevant as call targets for this check, with the position of the argument pointing to the destination buffer, and the position of the argument that references the buffer that should be appended at the end of the destination buffer.

copy_operations¶

copy_operations

Type: dict[bauhaus.analysis.config.QualifiedName, typing.Tuple[int, int]]

Default:
{
   'strcpy': (0, 1)
}

Names of buffer copy functions being relevant as call targets for this check, with the position of the destination argument and the source argument of the buffer copy operation.

delimiter_of_arguments¶

delimiter_of_arguments

Type: dict[bauhaus.analysis.config.QualifiedName, set[int]]

Default:

{
   'strcat': {0, 1},
   'strchr': {0},
   'strcmp': {0, 1},
   'strcoll': {0, 1},
   'strcpy': {1},
   'strcspn': {0, 1},
   'strlen': {0},
   'strncat': {0, 1},
   'strpbrk': {0, 1},
   'strrchr': {0},
   'strspn': {0, 1},
   'strstr': {0, 1},
   'strtok': {0, 1},
   'wcscat': {0, 1},
   'wcschr': {0},
   'wcscmp': {0, 1},
   'wcscpy': {1},
   'wcscspn': {0, 1},
   'wcslen': {0},
   'wcsncat': {0, 1},
   'wcsrchr': {0},
   'wcsspn': {0, 1}
}

Names of functions being relevant as call targets for this check, with the position of parameters whose referenced buffers should be checked for being properly terminated by a null terminator.

exclude_from_pointer_to_const_param_check¶

exclude_from_pointer_to_const_param_check : set[bauhaus.analysis.config.QualifiedName] = {'__builtin_object_size'}

Names of routines whose parameters should be excluded from the check for passing uninitialized variables by pointer as parameter with pointer-to-const type.

exclude_warnings_for_unknown_arguments¶

exclude_warnings_for_unknown_arguments : bool = False

Exclude warnings for cases where nothing at all is known about the arguments of an operation, caused e.g. by using return values of external routines.

ignore_calls_in_functions¶

ignore_calls_in_functions : set[bauhaus.analysis.config.QualifiedName] = set()

Qualified names of function definitions in which calls to relevant functions are ignored for this check.

track_conditional_initialization¶

track_conditional_initialization : bool = True

Whether higher precision should be used to eliminate cases where the initialization and the access are controlled by conditions in a way that the variable access is only executed when the initialization was executed. Requires more memory and runtime but can eliminate some false positives.

use_semantic_analysis¶

use_semantic_analysis : bool = True

When enabled, use semantic analysis. Otherwise filter uninitialized variable messages from the compiler.

writing_into_pointer_to_const¶

writing_into_pointer_to_const

Type: dict[bauhaus.analysis.config.QualifiedName, int]

Default:
{
   'cudaMemcpyToSymbol': 0
}

Names of routines (mapping to parameter index, starting at 0) having a parameter declared as pointer-to-const yet they are still writing into the pointee.

Axivion Suite 7.12.0

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