libdar::secu_string Class Reference

class secu_string More...

#include <secu_string.hpp>

Collaboration diagram for libdar::secu_string:

Public Member Functions
	secu_string (U_I storage_size=0)
	constructor 1 More...
	secu_string (const char *ptr, U_I size)
	constructor 2 More...
	secu_string (const secu_string &ref)
	the copy constructor
	secu_string (secu_string &&ref) noexcept
	the move constructor
secu_string &	operator= (const secu_string &ref)
	the assignment operator
secu_string &	operator= (secu_string &&ref) noexcept
	the move operator
	~secu_string () noexcept
	the destructor (set memory to zero before releasing it)
bool	operator!= (const std::string &ref) const
bool	operator!= (const secu_string &ref) const
bool	operator== (const std::string &ref) const
bool	operator== (const secu_string &ref) const
void	set (int fd, U_I size)
	fill the object with data More...
void	append_at (U_I offset, const char *ptr, U_I size)
	append some data to the string at a given offset More...
void	append_at (U_I offset, int fd, U_I size)
	append some data to the string
void	append (const char *ptr, U_I size)
	append some data at the end of the string
void	append (int fd, U_I size)
	append some data at the end of the string
void	reduce_string_size_to (U_I pos)
void	expand_string_size_to (U_I size)
	set the string size within the allocated secure memory
void	clear ()
	clear the string (set to an empty string)
void	resize (U_I size)
	clear and resize the string to the defined allocated size More...
void	randomize (U_I size)
	set the string to randomize string of given size More...
const char *	c_str () const
	get access to the secure string More...
char *	c_str ()
void	set_size (U_I size)
char *	get_array ()
	non constant flavor of direct secure memory access
char &	operator[] (U_I index)
	get access to the secure string by index More...
char	operator[] (U_I index) const
U_I	get_size () const
	get the size of the string
bool	empty () const
	tell whether string is empty
U_I	get_allocated_size () const
	get the size of the allocated secure space

Static Public Member Functions
static bool	is_string_secured ()
	to know if secure memory is available More...

Private Member Functions
void	nullifyptr () noexcept
void	init (U_I size)
void	copy_from (const secu_string &ref)
void	move_from (secu_string &&ref) noexcept
bool	compare_with (const char *ptr, U_I size) const
void	clean_and_destroy ()

Private Attributes
U_I *	allocated_size
char *	mem
U_I *	string_size

Detailed Description

class secu_string

it manages the allocation/release of a given size block of memory the memory block is forbidden to be swapped (if is_strin_secured() is true) and is zeroed before being released

Definition at line 53 of file secu_string.hpp.

Constructor & Destructor Documentation

secu_string() [1/2]

libdar::secu_string::secu_string ( U_I  storage_size = 0 )

inline

constructor 1

create the allocated string in secure memory

Parameters

[in]

storage_size

is the amount of secured memory to obtain when creating the object

Definition at line 68 of file secu_string.hpp.

secu_string() [2/2]

libdar::secu_string::secu_string ( const char *  ptr, U_I  size  )

inline

constructor 2

create the string from a pointer to a (secure) string or from a portion of it

Definition at line 73 of file secu_string.hpp.

References append_at().

Member Function Documentation

append_at()

void libdar::secu_string::append_at	(	U_I	offset,
		const char *	ptr,
		U_I	size
	)

append some data to the string at a given offset

Parameters

[in]	offset	defines at which offset in the secu_string will be placed the string to append
[in]	ptr	is the address of the string to append
[in]	size	is the number of byte to append

Note

this call does not change the allocation size, (unlike set()), it adds the data pointed by the arguments to the object while there is enough place to do so. resize() must be used first to define enough secure memory to append the expected amount of data in one or several call to append.

Referenced by append(), and secu_string().

c_str()

const char* libdar::secu_string::c_str ( ) const

inline

get access to the secure string

Returns

the address of the first byte of the string

Note

check the "size" method to know how much bytes can be read

Definition at line 152 of file secu_string.hpp.

is_string_secured()

static bool libdar::secu_string::is_string_secured ( )

static

to know if secure memory is available

it is advised that the user program of class secu_string uses this call before using objects of that class and if returned false, advise the user that the necessary support for secure memory is not present, that any sensitive data may be swapped out under heavy memory load and thus may lead secure password to be wrote to disk in clear.

operator[]()

char& libdar::secu_string::operator[]

(

U_I

index

)

get access to the secure string by index

Note

index must be in the range [ 0 - size() [ to avoid throwing an exception

randomize()

void libdar::secu_string::randomize

(

U_I

size

)

set the string to randomize string of given size

Note

the given size must be less than allocated size

reduce_string_size_to()

void libdar::secu_string::reduce_string_size_to

(

U_I

pos

)

shorten the string (do not change the allocated size)

Parameters

[in]

pos

is the length of the string to set, it must be smaller or equal to the current size

resize()

void libdar::secu_string::resize ( U_I  size )

inline

clear and resize the string to the defined allocated size

Parameters

[in]

size

is the amount of secure memory to allocated

Definition at line 141 of file secu_string.hpp.

set()

void libdar::secu_string::set	(	int	fd,
		U_I	size
	)

fill the object with data

set at most size bytes of data directly from the filedescriptor,

Parameters

[in]	fd	the filedescriptor to read data from
[in]	size	is the maximum number of byte read

Note

if current storage size is not larg enough to hold size bytes, allocated secure memory is released and larger allocation of secure memory is done.

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The documentation for this class was generated from the following file:

• secu_string.hpp