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Kernel: Add initial basic support for KASAN

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This commit adds minimal support for compiler-instrumentation based
memory access sanitization.
Currently we only support detection of kmalloc redzone accesses, and
kmalloc use-after-free accesses.

Support for inline checks (for improved performance), and for stack
use-after-return and use-after-return detection is left for future PRs.
This commit is contained in:
Idan Horowitz 2023-12-29 02:36:39 +02:00 • committed by Andreas Kling
parent 7ad7ae7000
commit f7a1f28d7f
10 changed files with 538 additions and 63 deletions
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25
Kernel/Memory/MemoryManager.cpp
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@ -24,6 +24,7 @@
#include <Kernel/Memory/SharedInodeVMObject.h>
#include <Kernel/Prekernel/Prekernel.h>
#include <Kernel/Sections.h>
#include <Kernel/Security/AddressSanitizer.h>
#include <Kernel/Tasks/Process.h>
extern u8 start_of_kernel_image[];
@ -105,6 +106,10 @@ UNMAP_AFTER_INIT MemoryManager::MemoryManager()
// By using a tag we don't have to query the VMObject for every page
// whether it was committed or not
m_lazy_committed_page = committed_pages.take_one();
#ifdef HAS_ADDRESS_SANITIZER
initialize_kasan_shadow_memory();
#endif
}
UNMAP_AFTER_INIT MemoryManager::~MemoryManager() = default;
@ -579,6 +584,26 @@ UNMAP_AFTER_INIT void MemoryManager::initialize_physical_pages()
});
}
#ifdef HAS_ADDRESS_SANITIZER
void MemoryManager::initialize_kasan_shadow_memory()
{
m_global_data.with([&](auto& global_data) {
// We map every 8 bytes of normal memory to 1 byte of shadow memory, so we need a 1/9 of total memory for the shadow memory.
auto virtual_range = global_data.region_tree.total_range();
auto shadow_range_size = MUST(page_round_up(ceil_div(virtual_range.size(), 9ul)));
dbgln("MM: Reserving {} bytes for KASAN shadow memory", shadow_range_size);
auto vmobject = MUST(AnonymousVMObject::try_create_with_size(shadow_range_size, AllocationStrategy::AllocateNow));
auto* shadow_region = MUST(Region::create_unplaced(move(vmobject), 0, {}, Memory::Region::Access::ReadWrite)).leak_ptr();
auto shadow_range = VirtualRange { virtual_range.base().offset(virtual_range.size() - shadow_range_size), shadow_range_size };
MUST(global_data.region_tree.place_specifically(*shadow_region, shadow_range));
MUST(shadow_region->map(kernel_page_directory()));
AddressSanitizer::init(shadow_region->vaddr().get());
});
}
#endif
PhysicalPageEntry& MemoryManager::get_physical_page_entry(PhysicalAddress physical_address)
{
auto physical_page_entry_index = PhysicalAddress::physical_page_index(physical_address.get());