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→KernelLdr_LoadKernel
Next, it generates a random KASLR slide for the Kernel.
Next, it generates a random KASLR slide for the Kernel.
<pre>
<pre>
// TODO: Fill this out with pseudocode.
// Repeatedly try to generate a random slide
while (true) {
// Get random value from secure monitor in range
// This is "probably" KSystemControl::GenerateRandomRange, as in normal kernel
// However, it's unclear whether KSystemControl is actually included, or whether this is just copy/pasted?
random_kaslr_slide = KernelLdr_GenerateRandomRange(0xFFFFFF8000000000, 0xFFFFFFFFFFDFFFFF);
aligned_random_kaslr_slide = random_kaslr_slide & 0xFFFFFFFFFFE00000;
// Calculate end address for kernel with this slide, rounding up.
random_kernel_end = aligned_random_kaslr_slide + (kernel_base & 0x1FFFFF) + rw_end_offset + 0x1FFFFF) & 0x1FFE00000;
// Validate no overflow, and that the kernel will fit with the slide.
if (aligned_random_kaslr_slide >= random_kaslr_end || ((random_kaslr_end - 1) > 0xFFFFFFFFFFDFFFFF)) {
continue;
}
// Validate we can map this range without conflicts.
// NOTE: This is inlined, but code looks same as in older kernel binaries.
if (!ttbr1_page_table.IsFree(aligned_random_kaslr_slide, random_kernel_end - aligned_random_kaslr_slide)) {
continue;
}
// Valid kaslr slide, so we're done.
break;
}
final_virtual_kernel_base = aligned_random_kaslr_slide | (kernel_base & 0x1FFFFF);
</pre>
</pre>