Double free

Not to be confused with the memory management bug..

Double free

Designed by	User:RaiseAfloppaFan3925
Appeared in	2026
Computational class	Below combinational logic
Reference implementation	Unimplemented
Influenced by	Malloc

Double free is a programming language by User:RaiseAfloppaFan3925 inspired by and is a superset of Malloc. It is obviously based on the memory management bug. Here, you can only do two things: allocate memory, and free a pointer twice.

Syntax and semantics

Double free has the malloc command from Malloc, but it has an extension:

varname malloc x

This points the varname to the x bytes of memory allocated.

Additionally, allocating a negative amount of bytes will just wrap around, as you are trying to use a two's complement signed number in a function that expects an unsigned integer. Specifically, the argument to malloc is a size_t as defined by the C standard. So, the following program will just allocate an insane amount of memory.

malloc -1

Since size_t's size is platform-dependent, the amount of bytes this allocates is also varying.

Variables are implicitly defined as garbage values before the program starts, just to make the language more beginner-friendly.

Variables can then be used in the doublefree command as follows:

doublefree varname

This just frees the variable twice.

Since malloc(0) is implementation-defined in the C standard, it is also implementation-defined in Double free.

Examples

Allocate 5 bytes of memory and double-free it

x malloc 5
doublefree x

Allocate a gibibyte of memory and double-free it

ptr malloc 1099511627776
doublefree ptr

Leak 8 bytes and double-free 8 bytes

ptr1 malloc 8
ptr2 malloc 8
doublefree ptr1

Test memory security

x malloc 1024
doublefree x
x malloc 1024
doublefree x
x malloc 1024
doublefree x
x malloc 1024
doublefree x

I have no idea

doublefree a
doublefree b
doublefree c

This thing

ptr malloc -1

With a 16-bit size_t, this will allocate 65,536 bytes. With 32-bit size_ts, this will allocate 4 GiB. With 64-bit size_ts, this will allocate 18 quintillion bytes.

Wild card program

ptr malloc 0
doublefree ptr

See also

• Malloc