diff options
Diffstat (limited to 'Kernel')
| -rw-r--r-- | Kernel/Memory/MemoryManager.cpp | 11 | ||||
| -rw-r--r-- | Kernel/PhysicalAddress.h | 2 |
2 files changed, 9 insertions, 4 deletions
diff --git a/Kernel/Memory/MemoryManager.cpp b/Kernel/Memory/MemoryManager.cpp index 764fd0b887..377cea04ca 100644 --- a/Kernel/Memory/MemoryManager.cpp +++ b/Kernel/Memory/MemoryManager.cpp @@ -180,13 +180,16 @@ UNMAP_AFTER_INIT void MemoryManager::register_reserved_ranges() bool MemoryManager::is_allowed_to_mmap_to_userspace(PhysicalAddress start_address, VirtualRange const& range) const { VERIFY(!m_reserved_memory_ranges.is_empty()); + // Note: Guard against overflow in case someone tries to mmap on the edge of + // the RAM + if (start_address.offset_addition_would_overflow(range.size())) + return false; + auto end_address = start_address.offset(range.size()); for (auto& current_range : m_reserved_memory_ranges) { - if (!(current_range.start <= start_address)) + if (current_range.start > start_address) continue; - if (!(current_range.start.offset(current_range.length) > start_address)) + if (current_range.start.offset(current_range.length) < end_address) continue; - if (current_range.length < range.size()) - return false; return true; } return false; diff --git a/Kernel/PhysicalAddress.h b/Kernel/PhysicalAddress.h index 0a5d0aa4b4..f6d9367e00 100644 --- a/Kernel/PhysicalAddress.h +++ b/Kernel/PhysicalAddress.h @@ -6,6 +6,7 @@ #pragma once +#include <AK/Checked.h> #include <AK/Format.h> #include <AK/Types.h> @@ -30,6 +31,7 @@ public: } [[nodiscard]] PhysicalAddress offset(PhysicalPtr o) const { return PhysicalAddress(m_address + o); } + [[nodiscard]] bool offset_addition_would_overflow(PhysicalPtr o) const { return Checked<PhysicalPtr>::addition_would_overflow(m_address, o); } [[nodiscard]] PhysicalPtr get() const { return m_address; } void set(PhysicalPtr address) { m_address = address; } void mask(PhysicalPtr m) { m_address &= m; } |