Module kaslr 

Kernel Address Space Layout Randomization (KASLR)

Provides address randomization for kernel text, heap, stack, and module load addresses. Uses architecture-specific hardware entropy sources (RDRAND on x86_64, RNDR on AArch64) with an xorshift64 PRNG fallback for RISC-V and other architectures.

Design

KASLR offsets are computed once during boot and stored in a global KaslrState protected by a RwLock. The state includes:

• text_offset: Randomized slide for kernel text/code
• heap_offset: Randomized base offset for the kernel heap
• stack_offset: Default per-thread stack randomization quantum
• module_base: Randomized base for driver/module loading

Runtime re-randomization can refresh offsets for long-running systems, though the kernel text offset is typically fixed at boot.

Entropy Sources

Architecture	Primary Source	Fallback
x86_64	RDRAND	xorshift64 (TSC seed)
AArch64	RNDR	xorshift64 (CNTPCT seed)
RISC-V	N/A	xorshift64 (cycle seed)

Structs

KaslrState

Current KASLR offsets and PRNG state.

Functions

get_heap_offset

Get the kernel heap base randomization offset.

get_module_base

Get a randomized module/driver load base address.

get_offsets

Get a snapshot of current KASLR offsets for diagnostics.

get_text_offset

Get the kernel text randomization offset.

init

Initialize the KASLR subsystem.

is_active

Check if KASLR is initialized and active.

randomize_stack

Randomize a thread’s stack base by subtracting a random offset.

rerandomize

Re-randomize non-text KASLR offsets.

rerandomize_count

Get the number of re-randomizations performed.