transmission/libtransmission/blocklist.cc
Yat Ho 20aef2f79d
fix: misc net.cc and blocklist.cc fixes (#6717)
* fix: `tr_address` should be invalid by default

* fix: allow loopback address for LPD and incoming connections

* fix: `parseCidrline()` should set address type

* code review: keep `memcmp`
2024-03-24 17:09:51 -05:00

582 lines
16 KiB
C++

// This file Copyright © Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <algorithm>
#include <array>
#include <cstddef>
#include <cstdint>
#include <fstream>
#include <initializer_list>
#include <ios>
#include <optional>
#include <string> // std::getline()
#include <string_view>
#include <utility> // for std::move, std::pair
#include <vector>
#ifdef _WIN32
#include <ws2tcpip.h>
#else
#include <arpa/inet.h>
#include <cerrno>
#include <netinet/in.h>
#endif
#include <fmt/core.h>
#include "libtransmission/transmission.h"
#include "libtransmission/blocklist.h"
#include "libtransmission/error.h"
#include "libtransmission/file.h"
#include "libtransmission/log.h"
#include "libtransmission/net.h"
#include "libtransmission/tr-assert.h"
#include "libtransmission/tr-strbuf.h"
#include "libtransmission/utils.h" // for _(), tr_strerror(), tr_strv_ends_with()
using namespace std::literals;
namespace libtransmission
{
namespace
{
// A string at the beginning of .bin files to test & make sure we don't load incompatible files
auto constexpr BinContentsPrefix = std::string_view{ "-tr-blocklist-file-format-v3-" };
// In the blocklists directory, the The plaintext source file can be anything, e.g. "level1".
// The pre-parsed, fast-to-load binary file will have a ".bin" suffix e.g. "level1.bin".
auto constexpr BinFileSuffix = std::string_view{ ".bin" };
using address_range_t = std::pair<tr_address, tr_address>;
void save(std::string_view filename, address_range_t const* ranges, size_t n_ranges)
{
auto out = std::ofstream{ tr_pathbuf{ filename }, std::ios_base::out | std::ios_base::trunc | std::ios_base::binary };
if (!out.is_open())
{
tr_logAddWarn(fmt::format(
_("Couldn't read '{path}': {error} ({error_code})"),
fmt::arg("path", filename),
fmt::arg("error", tr_strerror(errno)),
fmt::arg("error_code", errno)));
return;
}
if (!out.write(std::data(BinContentsPrefix), std::size(BinContentsPrefix)) ||
!out.write(reinterpret_cast<char const*>(ranges), n_ranges * sizeof(*ranges)))
{
tr_logAddWarn(fmt::format(
_("Couldn't save '{path}': {error} ({error_code})"),
fmt::arg("path", filename),
fmt::arg("error", tr_strerror(errno)),
fmt::arg("error_code", errno)));
}
else
{
tr_logAddInfo(fmt::format(
tr_ngettext("Blocklist '{path}' has {count} entry", "Blocklist '{path}' has {count} entries", n_ranges),
fmt::arg("path", tr_sys_path_basename(filename)),
fmt::arg("count", n_ranges)));
}
out.close();
}
namespace ParseHelpers
{
// P2P plaintext format: "comment:x.x.x.x-y.y.y.y" / "comment:x:x:x:x:x:x:x:x-x:x:x:x:x:x:x:x"
// https://web.archive.org/web/20100328075307/http://wiki.phoenixlabs.org/wiki/P2P_Format
// https://en.wikipedia.org/wiki/PeerGuardian#P2P_plaintext_format
std::optional<address_range_t> parsePeerGuardianLine(std::string_view line)
{
// remove leading "comment:"
auto pos = line.find(':');
if (pos == std::string_view::npos)
{
return {};
}
line = line.substr(pos + 1);
// parse the leading 'x.x.x.x'
pos = line.find('-');
if (pos == std::string_view::npos)
{
return {};
}
auto addrpair = address_range_t{};
if (auto const addr = tr_address::from_string(line.substr(0, pos)); addr)
{
addrpair.first = *addr;
}
else
{
return {};
}
line = line.substr(pos + 1);
// parse the trailing 'y.y.y.y'
if (auto const addr = tr_address::from_string(line); addr)
{
addrpair.second = *addr;
}
else
{
return {};
}
return addrpair;
}
// DAT / eMule format: "000.000.000.000 - 000.255.255.255 , 000 , invalid ip"
// https://sourceforge.net/p/peerguardian/wiki/dev-blocklist-format-dat/
std::optional<address_range_t> parseEmuleLine(std::string_view line)
{
static auto constexpr Delim1 = std::string_view{ " - " };
static auto constexpr Delim2 = std::string_view{ " , " };
auto pos = line.find(Delim1);
if (pos == std::string_view::npos)
{
return {};
}
auto addrpair = address_range_t{};
if (auto const addr = tr_address::from_string(line.substr(0, pos)); addr)
{
addrpair.first = *addr;
}
else
{
return {};
}
line = line.substr(pos + std::size(Delim1));
pos = line.find(Delim2);
if (pos == std::string_view::npos)
{
return {};
}
if (auto const addr = tr_address::from_string(line.substr(0, pos)); addr)
{
addrpair.second = *addr;
}
else
{
return {};
}
return addrpair;
}
// CIDR notation: "0.0.0.0/8", "::/64"
// https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing#CIDR_notation
// Example: `10.5.6.7/8` will block the range [10.0.0.0 .. 10.255.255.255]
std::optional<address_range_t> parseCidrLine(std::string_view line)
{
auto addrpair = address_range_t{};
auto pos = line.find('/');
if (pos == std::string_view::npos)
{
return {};
}
if (auto const addr = tr_address::from_string(line.substr(0, pos)); addr && addr->is_ipv4())
{
addrpair.first = *addr;
}
else
{
return {};
}
auto const pflen = tr_num_parse<size_t>(line.substr(pos + 1));
if (!pflen)
{
return {};
}
auto const mask = ~(~uint32_t{ 0 } >> *pflen);
auto const ip_u = ntohl(addrpair.first.addr.addr4.s_addr);
auto tmp = htonl(ip_u & mask);
std::tie(addrpair.first, std::ignore) = tr_address::from_compact_ipv4(reinterpret_cast<std::byte*>(&tmp));
tmp = htonl(ip_u | (~mask));
std::tie(addrpair.second, std::ignore) = tr_address::from_compact_ipv4(reinterpret_cast<std::byte*>(&tmp));
return addrpair;
}
std::optional<address_range_t> parseLine(std::string_view line)
{
for (auto const& line_parser : { parsePeerGuardianLine, parseEmuleLine, parseCidrLine })
{
if (auto range = line_parser(line); range)
{
return range;
}
}
return {};
}
} // namespace ParseHelpers
auto parseFile(std::string_view filename)
{
using namespace ParseHelpers;
auto ranges = std::vector<address_range_t>{};
auto in = std::ifstream{ tr_pathbuf{ filename } };
if (!in.is_open())
{
tr_logAddWarn(fmt::format(
_("Couldn't read '{path}': {error} ({error_code})"),
fmt::arg("path", filename),
fmt::arg("error", tr_strerror(errno)),
fmt::arg("error_code", errno)));
return ranges;
}
auto line = std::string{};
auto line_number = size_t{ 0U };
while (std::getline(in, line))
{
++line_number;
if (auto range = parseLine(line); range && (range->first.type == range->second.type))
{
ranges.push_back(*range);
}
else
{
// don't try to display the actual lines - it causes issues
tr_logAddWarn(fmt::format(_("Couldn't parse line: '{line}'"), fmt::arg("line", line_number)));
}
}
in.close();
if (std::empty(ranges))
{
return ranges;
}
// safeguard against some joker swapping the begin & end ranges
for (auto& [low, high] : ranges)
{
if (low > high)
{
std::swap(low, high);
}
}
// sort ranges by start address
std::sort(std::begin(ranges), std::end(ranges), [](auto const& a, auto const& b) { return a.first < b.first; });
// merge overlapping ranges
auto keep = size_t{ 0U };
for (auto const& range : ranges)
{
if (ranges[keep].second < range.first)
{
ranges[++keep] = range;
}
else if (ranges[keep].second < range.second)
{
ranges[keep].second = range.second;
}
}
TR_ASSERT_MSG(keep + 1 <= std::size(ranges), "Can shrink `ranges` or leave intact, but not grow");
ranges.resize(keep + 1);
#ifdef TR_ENABLE_ASSERTS
for (auto const& [low, high] : ranges)
{
TR_ASSERT(low <= high);
}
for (size_t i = 1, n = std::size(ranges); i < n; ++i)
{
TR_ASSERT(ranges[i - 1].second < ranges[i].first);
}
#endif
return ranges;
}
auto getFilenamesInDir(std::string_view folder)
{
auto const prefix = std::string{ folder } + '/';
auto files = tr_sys_dir_get_files(folder);
for (auto& file : files)
{
file.insert(0, prefix);
}
return files;
}
} // namespace
void Blocklists::Blocklist::ensureLoaded() const
{
if (!std::empty(rules_))
{
return;
}
// get the file's size
auto error = tr_error{};
auto const file_info = tr_sys_path_get_info(bin_file_, 0, &error);
if (error)
{
tr_logAddWarn(fmt::format(
_("Couldn't read '{path}': {error} ({error_code})"),
fmt::arg("path", bin_file_),
fmt::arg("error", error.message()),
fmt::arg("error_code", error.code())));
}
if (!file_info)
{
return;
}
// open the file
auto in = std::ifstream{ bin_file_, std::ios_base::in | std::ios_base::binary };
if (!in)
{
tr_logAddWarn(fmt::format(
_("Couldn't read '{path}': {error} ({error_code})"),
fmt::arg("path", bin_file_),
fmt::arg("error", tr_strerror(errno)),
fmt::arg("error_code", errno)));
return;
}
// check to see if the file is usable
bool supported_file = true;
if (file_info->size < std::size(BinContentsPrefix)) // too small
{
supported_file = false;
}
else if (((file_info->size - std::size(BinContentsPrefix)) % sizeof(address_range_t)) != 0) // wrong size
{
supported_file = false;
}
else
{
auto tmp = std::array<char, std::size(BinContentsPrefix)>{};
in.read(std::data(tmp), std::size(tmp));
supported_file = BinContentsPrefix == std::string_view{ std::data(tmp), std::size(tmp) };
}
if (!supported_file)
{
// bad binary file; try to rebuild it
in.close();
if (auto const sz_src_file = std::string{ std::data(bin_file_), std::size(bin_file_) - std::size(BinFileSuffix) };
tr_sys_path_exists(sz_src_file))
{
rules_ = parseFile(sz_src_file);
if (!std::empty(rules_))
{
tr_logAddInfo(_("Rewriting old blocklist file format to new format"));
tr_sys_path_remove(bin_file_);
save(bin_file_, std::data(rules_), std::size(rules_));
}
}
return;
}
auto range = address_range_t{};
rules_.reserve((file_info->size - std::size(BinContentsPrefix)) / sizeof(address_range_t));
while (in.read(reinterpret_cast<char*>(&range), sizeof(range)))
{
rules_.emplace_back(range);
}
tr_logAddInfo(fmt::format(
tr_ngettext("Blocklist '{path}' has {count} entry", "Blocklist '{path}' has {count} entries", std::size(rules_)),
fmt::arg("path", tr_sys_path_basename(bin_file_)),
fmt::arg("count", std::size(rules_))));
}
bool Blocklists::Blocklist::contains(tr_address const& addr) const
{
TR_ASSERT(addr.is_valid());
if (!is_enabled_)
{
return false;
}
ensureLoaded();
struct Compare
{
[[nodiscard]] static auto compare(tr_address const& a, address_range_t const& b) noexcept // <=>
{
if (a < b.first)
{
return -1;
}
if (b.second < a)
{
return 1;
}
return 0;
}
[[nodiscard]] static auto compare(address_range_t const& a, tr_address const& b) noexcept // <=>
{
return -compare(b, a);
}
[[nodiscard]] auto operator()(address_range_t const& a, tr_address const& b) const noexcept // <
{
return compare(a, b) < 0;
}
[[nodiscard]] auto operator()(tr_address const& a, address_range_t const& b) const noexcept // <
{
return compare(a, b) < 0;
}
};
return std::binary_search(std::begin(rules_), std::end(rules_), addr, Compare{});
}
std::optional<Blocklists::Blocklist> Blocklists::Blocklist::saveNew(
std::string_view external_file,
std::string_view bin_file,
bool is_enabled)
{
// if we can't parse the file, do nothing
auto rules = parseFile(external_file);
if (std::empty(rules))
{
return {};
}
// make a copy of `external_file` for our own safekeeping
auto const src_file = std::string{ std::data(bin_file), std::size(bin_file) - std::size(BinFileSuffix) };
tr_sys_path_remove(src_file.c_str());
auto error = tr_error{};
auto const copied = tr_sys_path_copy(tr_pathbuf{ external_file }, src_file.c_str(), &error);
if (error)
{
tr_logAddWarn(fmt::format(
_("Couldn't save '{path}': {error} ({error_code})"),
fmt::arg("path", src_file),
fmt::arg("error", error.message()),
fmt::arg("error_code", error.code())));
}
if (!copied)
{
return {};
}
save(bin_file, std::data(rules), std::size(rules));
// return a new Blocklist with these rules
auto ret = Blocklist{ bin_file, is_enabled };
ret.rules_ = std::move(rules);
return ret;
}
// ---
void Blocklists::set_enabled(bool is_enabled)
{
for (auto& blocklist : blocklists_)
{
blocklist.setEnabled(is_enabled);
}
changed_.emit();
}
void Blocklists::load(std::string_view folder, bool is_enabled)
{
folder_ = folder;
blocklists_ = load_folder(folder, is_enabled);
changed_.emit();
}
// static
std::vector<Blocklists::Blocklist> Blocklists::Blocklists::load_folder(std::string_view const folder, bool const is_enabled)
{
// check for files that need to be updated
for (auto const& src_file : getFilenamesInDir(folder))
{
if (tr_strv_ends_with(src_file, BinFileSuffix))
{
continue;
}
// ensure this src_file has an up-to-date corresponding bin_file
auto const src_info = tr_sys_path_get_info(src_file);
auto const bin_file = tr_pathbuf{ src_file, BinFileSuffix };
auto const bin_info = tr_sys_path_get_info(bin_file);
auto const bin_needs_update = src_info && (!bin_info || bin_info->last_modified_at <= src_info->last_modified_at);
if (bin_needs_update)
{
if (auto const ranges = parseFile(src_file); !std::empty(ranges))
{
save(bin_file, std::data(ranges), std::size(ranges));
}
}
}
auto ret = std::vector<Blocklist>{};
for (auto const& bin_file : getFilenamesInDir(folder))
{
if (tr_strv_ends_with(bin_file, BinFileSuffix))
{
ret.emplace_back(bin_file, is_enabled);
}
}
return ret;
}
size_t Blocklists::update_primary_blocklist(std::string_view external_file, bool is_enabled)
{
// These rules will replace the default blocklist.
// Build the path of the default blocklist .bin file where we'll save these rules.
auto const bin_file = tr_pathbuf{ folder_, '/', DEFAULT_BLOCKLIST_FILENAME };
// Try to save it
auto added = Blocklist::saveNew(external_file, bin_file, is_enabled);
if (!added)
{
return 0U;
}
auto const n_rules = std::size(*added);
// Add (or replace) it in our blocklists_ vector
if (auto iter = std::find_if(
std::begin(blocklists_),
std::end(blocklists_),
[&bin_file](auto const& candidate) { return bin_file == candidate.binFile(); });
iter != std::end(blocklists_))
{
*iter = std::move(*added);
}
else
{
blocklists_.emplace_back(std::move(*added));
}
changed_.emit();
return n_rules;
}
} // namespace libtransmission