dns.mitm: parse redirections from hosts file

This commit is contained in:
Michael Scire 2021-01-30 19:50:49 -08:00 committed by SciresM
parent 400f5142ee
commit d6477cf024
9 changed files with 378 additions and 9 deletions

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@ -42,6 +42,13 @@
; enabled or disabled. ; enabled or disabled.
; 0 = Disabled (not debug mode), 1 = Enabled (debug mode) ; 0 = Disabled (not debug mode), 1 = Enabled (debug mode)
; enable_am_debug_mode = u8!0x0 ; enable_am_debug_mode = u8!0x0
; Controls whether dns.mitm is enabled
; 0 = Disabled, 1 = Enabled
; atmosphere!enable_dns_mitm = u8!0x1
; Controls whether dns.mitm uses the default redirections in addition to
; whatever is specified in the user's hosts file.
; 0 = Disabled (use hosts file contents), 1 = Enabled (use defaults and hosts file contents)
; atmosphere!add_defaults_to_dns_hosts = u8!0x0
[hbloader] [hbloader]
; Controls the size of the homebrew heap when running as applet. ; Controls the size of the homebrew heap when running as applet.
; If set to zero, all available applet memory is used as heap. ; If set to zero, all available applet memory is used as heap.

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@ -22,6 +22,9 @@ namespace ams::emummc {
/* Get whether emummc is active. */ /* Get whether emummc is active. */
bool IsActive(); bool IsActive();
/* Get the active emummc id. */
u32 GetActiveId();
/* Get Nintendo redirection path. */ /* Get Nintendo redirection path. */
const char *GetNintendoDirPath(); const char *GetNintendoDirPath();

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@ -57,10 +57,10 @@ namespace ams::emummc {
}; };
/* Globals. */ /* Globals. */
os::Mutex g_lock(false); constinit os::SdkMutex g_lock;
ExosphereConfig g_exo_config; constinit ExosphereConfig g_exo_config;
bool g_is_emummc; constinit bool g_is_emummc;
bool g_has_cached; constinit bool g_has_cached;
/* Helpers. */ /* Helpers. */
void CacheValues() { void CacheValues() {
@ -110,6 +110,12 @@ namespace ams::emummc {
return g_is_emummc; return g_is_emummc;
} }
/* Get the active emummc id. */
u32 GetActiveId() {
CacheValues();
return g_exo_config.base_cfg.id;
}
/* Get Nintendo redirection path. */ /* Get Nintendo redirection path. */
const char *GetNintendoDirPath() { const char *GetNintendoDirPath() {
CacheValues(); CacheValues();

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@ -47,6 +47,36 @@ namespace ams::mitm::fs {
return fsFsCreateFile(&g_sd_filesystem, path, size, option); return fsFsCreateFile(&g_sd_filesystem, path, size, option);
} }
Result DeleteSdFile(const char *path) {
R_TRY(EnsureSdInitialized());
return fsFsDeleteFile(&g_sd_filesystem, path);
}
bool HasSdFile(const char *path) {
if (R_FAILED(EnsureSdInitialized())) {
return false;
}
FsDirEntryType type;
if (R_FAILED(fsFsGetEntryType(&g_sd_filesystem, path, &type))) {
return false;
}
return type == FsDirEntryType_File;
}
bool HasAtmosphereSdFile(const char *path) {
char fixed_path[ams::fs::EntryNameLengthMax + 1];
FormatAtmosphereSdPath(fixed_path, sizeof(fixed_path), path);
return HasSdFile(fixed_path);
}
Result DeleteAtmosphereSdFile(const char *path) {
char fixed_path[ams::fs::EntryNameLengthMax + 1];
FormatAtmosphereSdPath(fixed_path, sizeof(fixed_path), path);
return DeleteSdFile(fixed_path);
}
Result CreateAtmosphereSdFile(const char *path, s64 size, s32 option) { Result CreateAtmosphereSdFile(const char *path, s64 size, s32 option) {
char fixed_path[ams::fs::EntryNameLengthMax + 1]; char fixed_path[ams::fs::EntryNameLengthMax + 1];
FormatAtmosphereSdPath(fixed_path, sizeof(fixed_path), path); FormatAtmosphereSdPath(fixed_path, sizeof(fixed_path), path);

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@ -22,6 +22,7 @@ namespace ams::mitm::fs {
void OpenGlobalSdCardFileSystem(); void OpenGlobalSdCardFileSystem();
/* Utilities. */ /* Utilities. */
Result DeleteAtmosphereSdFile(const char *path);
Result CreateSdFile(const char *path, s64 size, s32 option); Result CreateSdFile(const char *path, s64 size, s32 option);
Result CreateAtmosphereSdFile(const char *path, s64 size, s32 option); Result CreateAtmosphereSdFile(const char *path, s64 size, s32 option);
Result OpenSdFile(FsFile *out, const char *path, u32 mode); Result OpenSdFile(FsFile *out, const char *path, u32 mode);
@ -30,6 +31,9 @@ namespace ams::mitm::fs {
Result OpenAtmosphereSdRomfsFile(FsFile *out, ncm::ProgramId program_id, const char *path, u32 mode); Result OpenAtmosphereSdRomfsFile(FsFile *out, ncm::ProgramId program_id, const char *path, u32 mode);
Result OpenAtmosphereRomfsFile(FsFile *out, ncm::ProgramId program_id, const char *path, u32 mode, FsFileSystem *fs); Result OpenAtmosphereRomfsFile(FsFile *out, ncm::ProgramId program_id, const char *path, u32 mode, FsFileSystem *fs);
bool HasSdFile(const char *path);
bool HasAtmosphereSdFile(const char *path);
Result CreateSdDirectory(const char *path); Result CreateSdDirectory(const char *path);
Result CreateAtmosphereSdDirectory(const char *path); Result CreateAtmosphereSdDirectory(const char *path);
Result OpenSdDirectory(FsDir *out, const char *path, u32 mode); Result OpenSdDirectory(FsDir *out, const char *path, u32 mode);

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@ -17,15 +17,298 @@
#include "../amsmitm_fs_utils.hpp" #include "../amsmitm_fs_utils.hpp"
#include "dnsmitm_debug.hpp" #include "dnsmitm_debug.hpp"
#include "dnsmitm_host_redirection.hpp" #include "dnsmitm_host_redirection.hpp"
#include "socket_allocator.hpp"
namespace ams::mitm::socket::resolver { namespace ams::mitm::socket::resolver {
namespace {
constexpr const char DefaultHostsFile[] =
"# Nintendo telemetry servers\n"
"127.0.0.1 receive-lp1.dg.srv.nintendo.net\n"
"127.0.0.1 receive-lp1.er.srv.nintendo.net\n";
constinit os::SdkMutex g_redirection_lock;
std::unordered_map<std::string, ams::socket::InAddrT> g_redirection_map;
constinit char g_specific_emummc_hosts_path[0x40] = {};
void ParseHostsFile(const char *file_data) {
enum class State {
IgnoredLine,
BeginLine,
Ip1,
IpDot1,
Ip2,
IpDot2,
Ip3,
IpDot3,
Ip4,
WhiteSpace,
HostName,
};
ams::socket::InAddrT current_address;
char current_hostname[0x200];
u32 work;
State state = State::BeginLine;
for (const char *cur = file_data; *cur != '\x00'; ++cur) {
const char c = *cur;
switch (state) {
case State::IgnoredLine:
if (c == '\n') {
state = State::BeginLine;
}
break;
case State::BeginLine:
if (std::isdigit(static_cast<unsigned char>(c))) {
current_address = 0;
work = static_cast<u32>(c - '0');
state = State::Ip1;
} else {
state = State::IgnoredLine;
}
break;
case State::Ip1:
if (std::isdigit(static_cast<unsigned char>(c))) {
work *= 10;
work += static_cast<u32>(c - '0');
} else if (c == '.') {
current_address |= (work & 0xFF) << 0;
work = 0;
state = State::IpDot1;
} else {
state = State::IgnoredLine;
}
break;
case State::IpDot1:
if (std::isdigit(static_cast<unsigned char>(c))) {
work = static_cast<u32>(c - '0');
state = State::Ip2;
} else {
state = State::IgnoredLine;
}
break;
case State::Ip2:
if (std::isdigit(static_cast<unsigned char>(c))) {
work *= 10;
work += static_cast<u32>(c - '0');
} else if (c == '.') {
current_address |= (work & 0xFF) << 8;
work = 0;
state = State::IpDot2;
} else {
state = State::IgnoredLine;
}
break;
case State::IpDot2:
if (std::isdigit(static_cast<unsigned char>(c))) {
work = static_cast<u32>(c - '0');
state = State::Ip3;
} else {
state = State::IgnoredLine;
}
break;
case State::Ip3:
if (std::isdigit(static_cast<unsigned char>(c))) {
work *= 10;
work += static_cast<u32>(c - '0');
} else if (c == '.') {
current_address |= (work & 0xFF) << 16;
work = 0;
state = State::IpDot3;
} else {
state = State::IgnoredLine;
}
break;
case State::IpDot3:
if (std::isdigit(static_cast<unsigned char>(c))) {
work = static_cast<u32>(c - '0');
state = State::Ip4;
} else {
state = State::IgnoredLine;
}
break;
case State::Ip4:
if (std::isdigit(static_cast<unsigned char>(c))) {
work *= 10;
work += static_cast<u32>(c - '0');
} else if (c == ' ' || c == '\t') {
current_address |= (work & 0xFF) << 24;
work = 0;
state = State::WhiteSpace;
} else {
state = State::IgnoredLine;
}
break;
case State::WhiteSpace:
if (c == '\n') {
state = State::BeginLine;
} else if (c != ' ' && c != '\r' && c != '\t') {
current_hostname[0] = c;
work = 1;
state = State::HostName;
}
break;
case State::HostName:
if (c == ' ' || c == '\r' || c == '\n' || c == '\t') {
AMS_ABORT_UNLESS(work < sizeof(current_hostname));
current_hostname[work] = '\x00';
g_redirection_map[static_cast<const char *>(current_hostname)] = current_address;
if (c == '\n') {
state = State::BeginLine;
} else {
state = State::WhiteSpace;
}
} else {
AMS_ABORT_UNLESS(work < sizeof(current_hostname) - 1);
current_hostname[work++] = c;
}
}
}
if (state == State::HostName) {
AMS_ABORT_UNLESS(work < sizeof(current_hostname));
current_hostname[work] = '\x00';
g_redirection_map[static_cast<const char *>(current_hostname)] = current_address;
}
}
void Log(::FsFile &f, const char *fmt, ...) __attribute__((format(printf, 2, 3)));
void Log(::FsFile &f, const char *fmt, ...) {
char log_buf[0x100];
int len = 0;
{
std::va_list vl;
va_start(vl, fmt);
len = util::VSNPrintf(log_buf, sizeof(log_buf), fmt, vl);
va_end(vl);
}
s64 ofs;
R_ABORT_UNLESS(::fsFileGetSize(std::addressof(f), std::addressof(ofs)));
R_ABORT_UNLESS(::fsFileWrite(std::addressof(f), ofs, log_buf, len, FsWriteOption_Flush));
}
const char *SelectHostsFile(::FsFile &log_file) {
Log(log_file, "Selecting hosts file...\n");
const bool is_emummc = emummc::IsActive();
const u32 emummc_id = emummc::GetActiveId();
util::SNPrintf(g_specific_emummc_hosts_path, sizeof(g_specific_emummc_hosts_path), "/hosts/emummc_%04x", emummc_id);
if (is_emummc) {
if (mitm::fs::HasAtmosphereSdFile(g_specific_emummc_hosts_path)) {
return g_specific_emummc_hosts_path;
}
Log(log_file, "Skipping %s because it does not exist...\n", g_specific_emummc_hosts_path);
if (mitm::fs::HasAtmosphereSdFile("/hosts/emummc")) {
return "/hosts/emummc";
}
Log(log_file, "Skipping %s because it does not exist...\n", "/hosts/emummc");
} else {
if (mitm::fs::HasAtmosphereSdFile("/hosts/sysmmc")) {
return "/hosts/sysmmc";
}
Log(log_file, "Skipping %s because it does not exist...\n", "/hosts/sysmmc");
}
return "/hosts/default";
}
}
void InitializeResolverRedirections(bool add_defaults) {
/* Acquire exclusive access to the map. */
std::scoped_lock lk(g_redirection_lock);
/* Clear the redirections map. */
g_redirection_map.clear();
/* Open log file. */
::FsFile log_file;
mitm::fs::DeleteAtmosphereSdFile("/dns_mitm_startup.log");
R_ABORT_UNLESS(mitm::fs::CreateAtmosphereSdFile("/dns_mitm_startup.log", 0, ams::fs::CreateOption_None));
R_ABORT_UNLESS(mitm::fs::OpenAtmosphereSdFile(std::addressof(log_file), "/dns_mitm_startup.log", ams::fs::OpenMode_ReadWrite | ams::fs::OpenMode_AllowAppend));
ON_SCOPE_EXIT { ::fsFileClose(std::addressof(log_file)); };
Log(log_file, "DNS Mitm:\n");
/* If a default hosts file doesn't exist on the sd card, create one. */
if (!mitm::fs::HasAtmosphereSdFile("/hosts/default")) {
Log(log_file, "Creating /hosts/default because it does not exist.\n");
mitm::fs::CreateAtmosphereSdDirectory("/hosts");
R_ABORT_UNLESS(mitm::fs::CreateAtmosphereSdFile("/hosts/default", sizeof(DefaultHostsFile) - 1, ams::fs::CreateOption_None));
::FsFile default_file;
R_ABORT_UNLESS(mitm::fs::OpenAtmosphereSdFile(std::addressof(default_file), "/hosts/default", ams::fs::OpenMode_ReadWrite));
R_ABORT_UNLESS(::fsFileWrite(std::addressof(default_file), 0, DefaultHostsFile, sizeof(DefaultHostsFile) - 1, ::FsWriteOption_Flush));
::fsFileClose(std::addressof(default_file));
}
/* If we should, add the defaults. */
if (add_defaults) {
Log(log_file, "Adding defaults to redirection list.\n");
ParseHostsFile(DefaultHostsFile);
}
/* Select the hosts file. */
const char *hosts_path = SelectHostsFile(log_file);
Log(log_file, "Selected %s\n", hosts_path);
/* Load the hosts file. */
{
char *hosts_file_data = nullptr;
ON_SCOPE_EXIT { if (hosts_file_data != nullptr) { ams::Free(hosts_file_data); } };
{
::FsFile hosts_file;
R_ABORT_UNLESS(mitm::fs::OpenAtmosphereSdFile(std::addressof(hosts_file), hosts_path, ams::fs::OpenMode_Read));
ON_SCOPE_EXIT { ::fsFileClose(std::addressof(hosts_file)); };
/* Get the hosts file size. */
s64 hosts_size;
R_ABORT_UNLESS(::fsFileGetSize(std::addressof(hosts_file), std::addressof(hosts_size)));
/* Validate we can read the file. */
AMS_ABORT_UNLESS(0 <= hosts_size && hosts_size < 0x8000);
/* Read the data. */
hosts_file_data = static_cast<char *>(ams::Malloc(0x8000));
AMS_ABORT_UNLESS(hosts_file_data != nullptr);
u64 br;
R_ABORT_UNLESS(::fsFileRead(std::addressof(hosts_file), 0, hosts_file_data, hosts_size, ::FsReadOption_None, std::addressof(br)));
AMS_ABORT_UNLESS(br == static_cast<u64>(hosts_size));
/* Null-terminate. */
hosts_file_data[hosts_size] = '\x00';
}
/* Parse the hosts file. */
ParseHostsFile(hosts_file_data);
}
/* Print the redirections. */
Log(log_file, "Redirections:\n");
for (const auto &[host, address] : g_redirection_map) {
Log(log_file, " `%s` -> %u.%u.%u.%u\n", host.c_str(), (address >> 0) & 0xFF, (address >> 8) & 0xFF, (address >> 16) & 0xFF, (address >> 24) & 0xFF);
}
}
bool GetRedirectedHostByName(ams::socket::InAddrT *out, const char *hostname) { bool GetRedirectedHostByName(ams::socket::InAddrT *out, const char *hostname) {
/* TODO: Real implementation */ std::scoped_lock lk(g_redirection_lock);
if (std::strcmp(hostname, "receive-lp1.dg.srv.nintendo.net") == 0) {
*out = ams::socket::InAddr_Loopback; for (const auto &[host, address] : g_redirection_map) {
if (std::strcmp(host.c_str(), hostname) == 0) {
*out = address;
return true; return true;
} }
}
return false; return false;
} }

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@ -18,6 +18,8 @@
namespace ams::mitm::socket::resolver { namespace ams::mitm::socket::resolver {
void InitializeResolverRedirections(bool add_defaults);
bool GetRedirectedHostByName(ams::socket::InAddrT *out, const char *hostname); bool GetRedirectedHostByName(ams::socket::InAddrT *out, const char *hostname);
} }

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@ -16,8 +16,9 @@
#include <stratosphere.hpp> #include <stratosphere.hpp>
#include "../amsmitm_initialization.hpp" #include "../amsmitm_initialization.hpp"
#include "dnsmitm_module.hpp" #include "dnsmitm_module.hpp"
#include "dnsmitm_resolver_impl.hpp"
#include "dnsmitm_debug.hpp" #include "dnsmitm_debug.hpp"
#include "dnsmitm_resolver_impl.hpp"
#include "dnsmitm_host_redirection.hpp"
namespace ams::mitm::socket::resolver { namespace ams::mitm::socket::resolver {
@ -93,15 +94,39 @@ namespace ams::mitm::socket::resolver {
} }
} }
bool ShouldMitmDns() {
u8 en = 0;
if (settings::fwdbg::GetSettingsItemValue(std::addressof(en), sizeof(en), "atmosphere", "enable_dns_mitm") == sizeof(en)) {
return (en != 0);
}
return false;
}
bool ShouldAddDefaultResolverRedirections() {
u8 en = 0;
if (settings::fwdbg::GetSettingsItemValue(std::addressof(en), sizeof(en), "atmosphere", "add_defaults_to_dns_hosts") == sizeof(en)) {
return (en != 0);
}
return false;
}
} }
void MitmModule::ThreadFunction(void *arg) { void MitmModule::ThreadFunction(void *arg) {
/* Wait until initialization is complete. */ /* Wait until initialization is complete. */
mitm::WaitInitialized(); mitm::WaitInitialized();
/* If we shouldn't mitm dns, don't do anything at all. */
if (!ShouldMitmDns()) {
return;
}
/* Initialize debug. */ /* Initialize debug. */
resolver::InitializeDebug(); resolver::InitializeDebug();
/* Initialize redirection map. */
resolver::InitializeResolverRedirections(ShouldAddDefaultResolverRedirections());
/* Create mitm servers. */ /* Create mitm servers. */
R_ABORT_UNLESS((g_server_manager.RegisterMitmServer<ResolverImpl>(PortIndex_Mitm, DnsMitmServiceName))); R_ABORT_UNLESS((g_server_manager.RegisterMitmServer<ResolverImpl>(PortIndex_Mitm, DnsMitmServiceName)));

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@ -349,6 +349,15 @@ namespace ams::settings::fwdbg {
/* 0 = Disabled (not debug mode), 1 = Enabled (debug mode) */ /* 0 = Disabled (not debug mode), 1 = Enabled (debug mode) */
R_ABORT_UNLESS(ParseSettingsItemValue("atmosphere", "enable_am_debug_mode", "u8!0x0")); R_ABORT_UNLESS(ParseSettingsItemValue("atmosphere", "enable_am_debug_mode", "u8!0x0"));
/* Controls whether dns.mitm is enabled. */
/* 0 = Disabled, 1 = Enabled */
R_ABORT_UNLESS(ParseSettingsItemValue("atmosphere", "enable_dns_mitm", "u8!0x1"));
/* Controls whether dns.mitm uses the default redirections in addition to */
/* whatever is specified in the user's hosts file. */
/* 0 = Disabled (use hosts file contents), 1 = Enabled (use defaults and hosts file contents) */
R_ABORT_UNLESS(ParseSettingsItemValue("atmosphere", "add_defaults_to_dns_hosts", "u8!0x0"));
/* Hbloader custom settings. */ /* Hbloader custom settings. */
/* Controls the size of the homebrew heap when running as applet. */ /* Controls the size of the homebrew heap when running as applet. */