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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.
This commit is contained in:
bunnei 2022-03-02 18:06:26 -08:00
parent f2743b41b0
commit 853e58e593
2 changed files with 63 additions and 25 deletions

View file

@ -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) &&

View file

@ -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<VAddr> MapProcessCodeMemory(Kernel::KProcess* process, VAddr baseAddress,
u64 size) const {
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)};
ResultVal<VAddr> 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++) {
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<VAddr> 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<VAddr, NROInfo> nro;
std::map<VAddr, std::vector<SHA256Hash>> nrr;
VAddr current_map_addr{};
bool IsValidNROHash(const SHA256Hash& hash) const {
return std::any_of(nrr.begin(), nrr.end(), [&hash](const auto& p) {