From 853e58e5932c4703bb521b5454a9b0fc325c7152 Mon Sep 17 00:00:00 2001 From: bunnei Date: Wed, 2 Mar 2022 18:06:26 -0800 Subject: hle: service: ldr: Use deterministic addresses when mapping NROs. - Instead of randomization, choose in-order addresses for where to map NROs into memory. - This results in predictable behavior when debugging and consistent behavior when reproducing issues. --- src/core/hle/kernel/k_page_table.h | 8 ++-- src/core/hle/service/ldr/ldr.cpp | 78 ++++++++++++++++++++++++++++---------- 2 files changed, 62 insertions(+), 24 deletions(-) (limited to 'src/core') diff --git a/src/core/hle/kernel/k_page_table.h b/src/core/hle/kernel/k_page_table.h index aea1b8f63..e99abe36a 100644 --- a/src/core/hle/kernel/k_page_table.h +++ b/src/core/hle/kernel/k_page_table.h @@ -253,7 +253,9 @@ public: constexpr bool IsInsideASLRRegion(VAddr address, std::size_t size) const { return !IsOutsideASLRRegion(address, size); } - + constexpr std::size_t GetNumGuardPages() const { + return IsKernel() ? 1 : 4; + } PAddr GetPhysicalAddr(VAddr addr) const { const auto backing_addr = page_table_impl.backing_addr[addr >> PageBits]; ASSERT(backing_addr); @@ -275,10 +277,6 @@ private: return is_aslr_enabled; } - constexpr std::size_t GetNumGuardPages() const { - return IsKernel() ? 1 : 4; - } - constexpr bool ContainsPages(VAddr addr, std::size_t num_pages) const { return (address_space_start <= addr) && (num_pages <= (address_space_end - address_space_start) / PageSize) && diff --git a/src/core/hle/service/ldr/ldr.cpp b/src/core/hle/service/ldr/ldr.cpp index 9fc7bb1b1..099276420 100644 --- a/src/core/hle/service/ldr/ldr.cpp +++ b/src/core/hle/service/ldr/ldr.cpp @@ -288,7 +288,7 @@ public: } bool ValidateRegionForMap(Kernel::KPageTable& page_table, VAddr start, std::size_t size) const { - constexpr std::size_t padding_size{4 * Kernel::PageSize}; + const std::size_t padding_size{page_table.GetNumGuardPages() * Kernel::PageSize}; const auto start_info{page_table.QueryInfo(start - 1)}; if (start_info.state != Kernel::KMemoryState::Free) { @@ -308,31 +308,69 @@ public: return (start + size + padding_size) <= (end_info.GetAddress() + end_info.GetSize()); } - VAddr GetRandomMapRegion(const Kernel::KPageTable& page_table, std::size_t size) const { - VAddr addr{}; - const std::size_t end_pages{(page_table.GetAliasCodeRegionSize() - size) >> - Kernel::PageBits}; - do { - addr = page_table.GetAliasCodeRegionStart() + - (Kernel::KSystemControl::GenerateRandomRange(0, end_pages) << Kernel::PageBits); - } while (!page_table.IsInsideAddressSpace(addr, size) || - page_table.IsInsideHeapRegion(addr, size) || - page_table.IsInsideAliasRegion(addr, size)); - return addr; + ResultCode GetAvailableMapRegion(Kernel::KPageTable& page_table, u64 size, VAddr& out_addr) { + size = Common::AlignUp(size, Kernel::PageSize); + size += page_table.GetNumGuardPages() * Kernel::PageSize * 4; + + const auto is_region_available = [&](VAddr addr) { + const auto end_addr = addr + size; + while (addr < end_addr) { + if (system.Memory().IsValidVirtualAddress(addr)) { + return false; + } + + if (!page_table.IsInsideAddressSpace(out_addr, size)) { + return false; + } + + if (page_table.IsInsideHeapRegion(out_addr, size)) { + return false; + } + + if (page_table.IsInsideAliasRegion(out_addr, size)) { + return false; + } + + addr += Kernel::PageSize; + } + return true; + }; + + bool succeeded = false; + const auto map_region_end = + page_table.GetAliasCodeRegionStart() + page_table.GetAliasCodeRegionSize(); + while (current_map_addr < map_region_end) { + if (is_region_available(current_map_addr)) { + succeeded = true; + break; + } + current_map_addr += 0x100000; + } + + if (!succeeded) { + UNREACHABLE_MSG("Out of address space!"); + return Kernel::ResultOutOfMemory; + } + + out_addr = current_map_addr; + current_map_addr += size; + + return ResultSuccess; } - ResultVal MapProcessCodeMemory(Kernel::KProcess* process, VAddr baseAddress, - u64 size) const { + ResultVal MapProcessCodeMemory(Kernel::KProcess* process, VAddr base_addr, u64 size) { + auto& page_table{process->PageTable()}; + VAddr addr{}; + for (std::size_t retry = 0; retry < MAXIMUM_MAP_RETRIES; retry++) { - auto& page_table{process->PageTable()}; - const VAddr addr{GetRandomMapRegion(page_table, size)}; - const ResultCode result{page_table.MapCodeMemory(addr, baseAddress, size)}; + R_TRY(GetAvailableMapRegion(page_table, size, addr)); + const ResultCode result{page_table.MapCodeMemory(addr, base_addr, size)}; if (result == Kernel::ResultInvalidCurrentMemory) { continue; } - CASCADE_CODE(result); + R_TRY(result); if (ValidateRegionForMap(page_table, addr, size)) { return addr; @@ -343,7 +381,7 @@ public: } ResultVal MapNro(Kernel::KProcess* process, VAddr nro_addr, std::size_t nro_size, - VAddr bss_addr, std::size_t bss_size, std::size_t size) const { + VAddr bss_addr, std::size_t bss_size, std::size_t size) { for (std::size_t retry = 0; retry < MAXIMUM_MAP_RETRIES; retry++) { auto& page_table{process->PageTable()}; VAddr addr{}; @@ -597,6 +635,7 @@ public: LOG_WARNING(Service_LDR, "(STUBBED) called"); initialized = true; + current_map_addr = system.CurrentProcess()->PageTable().GetAliasCodeRegionStart(); IPC::ResponseBuilder rb{ctx, 2}; rb.Push(ResultSuccess); @@ -607,6 +646,7 @@ private: std::map nro; std::map> nrr; + VAddr current_map_addr{}; bool IsValidNROHash(const SHA256Hash& hash) const { return std::any_of(nrr.begin(), nrr.end(), [&hash](const auto& p) { -- cgit v1.2.3