US 8,028,148 B2 · Safe and efficient allocation of memory

Abstract

Aspects of the present invention are directed at centrally managing the allocation of memory to executable images in a way that inhibits malware from identifying the location of the executable image. Moreover, performance improvements are implemented over traditional systems that enable relative addressed instruction to be resolved at runtime. In this regard, a method is provided that identifies a randomized location to load the executable image into a memory address space. Then, data that may be used to resolve the relative addressed instruction is loaded and maintained in memory. At runtime when pages that store relative addressed instructions are accessed, an arithmetic operation is performed to resolve the relative addressed instruction. As a result, only those relative addressed instructions on pages accessed during program execution are resolved.

Claims18

Dependent claims

In a computer configured to load pages of data from an executable image into a memory, a method of resolving a relative addressed instruction in the executable image at runtime, the method comprising:

identifying a randomized location to load the executable image into the memory at least in part by calculating an offset of the executable image, calculating the offset comprising at least in part reading a CPU time stamp that varies each time the computer is booted, the randomized location being based on a seed that causes data to be loaded over a contiguous area of the memory;
loading and maintaining data used to resolve the relative addressed instruction in the memory;
and
in response to a page that stores the relative addressed instruction being loaded into the memory at runtime, performing an arithmetic operation to resolve the relative addressed instruction.

1 more element

A computer-readable storage medium containing computer-readable instructions which, when executed in a computer with an operating system that supports on demand paging, performs a method comprising:

prefetching a relocation table associated with a program before the executable image is created, the relocation table being maintained in a memory during program execution;
determining whether relative addressed instructions in the executable image will straddle multiple pages;
if the relative addressed instructions in the executable image will not straddle multiple pages, moving the relative addressed instructions to a non-straddling location;
and
if the relative addressed instructions in the executable image will straddle multiple pages, recording, in the relocation table, information that describes attributes of the relative addressed instructions, the relative addressed instructions being resolved when the computer is in kernel mode, and pages that store the relative addressed instructions being accessed without being marked as modified.

2 more elements

Dependencies are inferred from the claim text.

Safe and efficient allocation of memory

Life of this patent

Safe and efficient allocation of memory

Life of this patent

Abstract

Claims18