Systems and methods for function pointer protection by function symbol encryption

An apparatus for protecting a function pointer by encrypting one or more function symbols, the apparatus comprising:

• a memory to store machine-readable instructions pertaining to the protection of the function pointer;
• and
• a computer processor coupled to the memory and operable to execute the machine-readable instructions stored in the memory, wherein the computer processor comprises:
• a compiler module to insert a plurality of sequences of a plurality of instructions at compile time for decrypting the function symbols to be randomized at runtime before a plurality of indirect function calls, wherein the compiler module inserts an instruction sequence at compile time for encrypting an operand register that receives a local function symbol in a position-independent code (PIC), where a call or store instruction uses the register as an operand;
• a static linker module to insert an encoding section at link time, wherein the encoding section comprises two columns representing sizes of the function symbols in bits or bytes and locations storing the function symbols to be encrypted at runtime;
• and
• an encryptor module to encrypt at runtime the function symbols whose sizes and stored locations are identified in the encoding section.

A non-transitory computer-readable storage medium having instructions encoded thereon that, when executed by a computing device, causes the computing device to perform operations comprising steps of:

• inserting a plurality of sequences of a plurality of instructions at compile time for decrypting the function symbols to be randomized at runtime before a plurality of indirect function calls;
• inserting an instruction sequence at compile time for encrypting an operand register that receives a local function symbol in a position-independent code (PIC), where a call or store instruction uses the register as an operand;
• inserting an encoding section at link time, wherein the encoding section comprises two columns representing sizes of the function symbols in bits or bytes and locations storing the function symbols to be encrypted at runtime;
• and
• encrypting at runtime the function symbols whose sizes and stored locations are identified in the encoding section.