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apt/methods/connect.cc
Daniel Baumann 6810ba718b
Adding upstream version 3.0.2. 
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
2025-06-20 21:10:43 +02:00

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// -*- mode: cpp; mode: fold -*-
// SPDX-License-Identifier: GPL-2.0+ and curl
// Description /*{{{*/
/* ######################################################################
Connect - Replacement connect call
This was originally authored by Jason Gunthorpe <jgg@debian.org>
and is placed in the Public Domain, do with it what you will. It
is now GPL-2.0+. See COPYING for details.
##################################################################### */
/*}}}*/
// Include Files /*{{{*/
#include <config.h>
#include <apt-pkg/acquire-method.h>
#include <apt-pkg/configuration.h>
#include <apt-pkg/error.h>
#include <apt-pkg/fileutl.h>
#include <apt-pkg/srvrec.h>
#include <apt-pkg/strutl.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <cassert>
#include <cerrno>
#include <cstdio>
#include <cstring>
#include <list>
#include <set>
#include <sstream>
#include <string>
#include <unistd.h>
// Internet stuff
#include <netdb.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/select.h>
#include <sys/socket.h>
#include "aptmethod.h"
#include "connect.h"
#include "rfc2553emu.h"
#include <apti18n.h>
/*}}}*/
static std::string LastHost;
static std::string LastService;
static struct addrinfo *LastHostAddr = 0;
static struct addrinfo *LastUsed = 0;
static std::vector<SrvRec> SrvRecords;
// Set of IP/hostnames that we timed out before or couldn't resolve
static std::set<std::string> bad_addr;
// RotateDNS - Select a new server from a DNS rotation /*{{{*/
// ---------------------------------------------------------------------
/* This is called during certain errors in order to recover by selecting a
new server */
void RotateDNS()
{
if (LastUsed != 0 && LastUsed->ai_next != 0)
LastUsed = LastUsed->ai_next;
else
LastUsed = LastHostAddr;
}
/*}}}*/
static bool ConnectionAllowed(char const * const Service, std::string const &Host)/*{{{*/
{
if (unlikely(Host.empty())) // the only legal empty host (RFC2782 '.' target) is detected by caller
return false;
if (APT::String::Endswith(Host, ".onion") && _config->FindB("Acquire::BlockDotOnion", true))
{
// TRANSLATOR: %s is e.g. Tor's ".onion" which would likely fail or leak info (RFC7686)
_error->Error(_("Direct connection to %s domains is blocked by default."), ".onion");
if (strcmp(Service, "http") == 0)
_error->Error(_("If you meant to use Tor remember to use %s instead of %s."), "tor+http", "http");
return false;
}
return true;
}
/*}}}*/
// File Descriptor based Fd /*{{{*/
struct FdFd final : public MethodFd
{
int fd = -1;
int Fd() override { return fd; }
ssize_t Read(void *buf, size_t count) override { return ::read(fd, buf, count); }
ssize_t Write(void *buf, size_t count) override { return ::write(fd, buf, count); }
int Close() override
{
int result = 0;
if (fd != -1)
result = ::close(fd);
fd = -1;
return result;
}
};
bool MethodFd::HasPending()
{
return false;
}
std::unique_ptr<MethodFd> MethodFd::FromFd(int iFd)
{
FdFd *fd = new FdFd();
fd->fd = iFd;
return std::unique_ptr<MethodFd>(fd);
}
/*}}}*/
// DoConnect - Attempt a connect operation /*{{{*/
// ---------------------------------------------------------------------
/* This helper function attempts a connection to a single address. */
struct Connection
{
struct addrinfo *Addr;
std::string Host;
aptMethod *Owner;
std::unique_ptr<FdFd> Fd;
char Name[NI_MAXHOST];
char Service[NI_MAXSERV];
Connection(struct addrinfo *Addr, std::string const &Host, aptMethod *Owner) : Addr(Addr), Host(Host), Owner(Owner), Fd(new FdFd()), Name{0}, Service{0}
{
}
// Allow moving values, but not connections.
Connection(Connection &&Conn) = default;
Connection(const Connection &Conn) = delete;
Connection &operator=(const Connection &) = delete;
Connection &operator=(Connection &&Conn) = default;
~Connection()
{
if (Fd != nullptr)
{
Fd->Close();
}
}
std::unique_ptr<MethodFd> Take()
{
/* Store the IP we are using.. If something goes
wrong this will get tacked onto the end of the error message */
std::stringstream ss;
ioprintf(ss, _("[IP: %s %s]"), Name, Service);
Owner->SetIP(ss.str());
Owner->Status(_("Connected to %s (%s)"), Host.c_str(), Name);
_error->Discard();
Owner->SetFailReason("");
LastUsed = Addr;
return std::move(Fd);
}
ResultState DoConnect();
ResultState CheckError();
};
ResultState Connection::DoConnect()
{
getnameinfo(Addr->ai_addr,Addr->ai_addrlen,
Name,sizeof(Name),Service,sizeof(Service),
NI_NUMERICHOST|NI_NUMERICSERV);
Owner->Status(_("Connecting to %s (%s)"),Host.c_str(),Name);
// if that addr did timeout before, we do not try it again
if(bad_addr.find(std::string(Name)) != bad_addr.end())
return ResultState::TRANSIENT_ERROR;
// Get a socket
if ((static_cast<FdFd *>(Fd.get())->fd = socket(Addr->ai_family, Addr->ai_socktype,
Addr->ai_protocol)) < 0)
{
_error->Errno("socket", _("Could not create a socket for %s (f=%u t=%u p=%u)"),
Name, Addr->ai_family, Addr->ai_socktype, Addr->ai_protocol);
return ResultState::FATAL_ERROR;
}
SetNonBlock(Fd->Fd(), true);
if (connect(Fd->Fd(), Addr->ai_addr, Addr->ai_addrlen) < 0 &&
errno != EINPROGRESS)
{
_error->Errno("connect", _("Cannot initiate the connection "
"to %s:%s (%s)."),
Host.c_str(), Service, Name);
return ResultState::TRANSIENT_ERROR;
}
return ResultState::SUCCESSFUL;
}
ResultState Connection::CheckError()
{
// Check the socket for an error condition
unsigned int Err;
unsigned int Len = sizeof(Err);
if (getsockopt(Fd->Fd(), SOL_SOCKET, SO_ERROR, &Err, &Len) != 0)
{
_error->Errno("getsockopt", _("Failed"));
return ResultState::FATAL_ERROR;
}
if (Err != 0)
{
errno = Err;
if(errno == ECONNREFUSED)
Owner->SetFailReason("ConnectionRefused");
else if (errno == ETIMEDOUT)
Owner->SetFailReason("ConnectionTimedOut");
bad_addr.insert(bad_addr.begin(), std::string(Name));
_error->Errno("connect", _("Could not connect to %s:%s (%s)."), Host.c_str(),
Service, Name);
return ResultState::TRANSIENT_ERROR;
}
Owner->SetFailReason("");
return ResultState::SUCCESSFUL;
}
/*}}}*/
// Order the given host names returned by getaddrinfo() /*{{{*/
static std::vector<struct addrinfo *> OrderAddresses(struct addrinfo *CurHost)
{
std::vector<struct addrinfo *> preferredAddrs;
std::vector<struct addrinfo *> otherAddrs;
std::vector<struct addrinfo *> allAddrs;
// Partition addresses into preferred and other address families
while (CurHost != 0)
{
if (preferredAddrs.empty() || CurHost->ai_family == preferredAddrs[0]->ai_family)
preferredAddrs.push_back(CurHost);
else
otherAddrs.push_back(CurHost);
// Ignore UNIX domain sockets
do
{
CurHost = CurHost->ai_next;
} while (CurHost != 0 && CurHost->ai_family == AF_UNIX);
/* If we reached the end of the search list then wrap around to the
start */
if (CurHost == 0 && LastUsed != 0)
CurHost = LastHostAddr;
// Reached the end of the search cycle
if (CurHost == LastUsed)
break;
}
// Build a new address vector alternating between preferred and other
for (auto prefIter = preferredAddrs.cbegin(), otherIter = otherAddrs.cbegin();
prefIter != preferredAddrs.end() || otherIter != otherAddrs.end();)
{
if (prefIter != preferredAddrs.end())
allAddrs.push_back(*prefIter++);
if (otherIter != otherAddrs.end())
allAddrs.push_back(*otherIter++);
}
return allAddrs;
}
/*}}}*/
// Check for errors and report them /*{{{*/
static ResultState WaitAndCheckErrors(std::list<Connection> &Conns, std::unique_ptr<MethodFd> &Fd, long TimeoutMsec, bool ReportTimeout)
{
// The last error detected
ResultState Result = ResultState::TRANSIENT_ERROR;
struct timeval tv = {
// Split our millisecond timeout into seconds and microseconds
.tv_sec = TimeoutMsec / 1000,
.tv_usec = (TimeoutMsec % 1000) * 1000,
};
// We will return once we have no more connections, a time out, or
// a success.
while (!Conns.empty())
{
fd_set Set;
int nfds = -1;
FD_ZERO(&Set);
for (auto &Conn : Conns)
{
int fd = Conn.Fd->Fd();
FD_SET(fd, &Set);
nfds = std::max(nfds, fd);
}
{
int Res;
do
{
Res = select(nfds + 1, 0, &Set, 0, (TimeoutMsec != 0 ? &tv : 0));
} while (Res < 0 && errno == EINTR);
if (Res == 0)
{
if (ReportTimeout)
{
for (auto &Conn : Conns)
{
Conn.Owner->SetFailReason("Timeout");
bad_addr.insert(bad_addr.begin(), Conn.Name);
_error->Error(_("Could not connect to %s:%s (%s), "
"connection timed out"),
Conn.Host.c_str(), Conn.Service, Conn.Name);
}
}
return ResultState::TRANSIENT_ERROR;
}
}
// iterate over connections, remove failed ones, and return if
// there was a successful one.
for (auto ConnI = Conns.begin(); ConnI != Conns.end();)
{
if (!FD_ISSET(ConnI->Fd->Fd(), &Set))
{
ConnI++;
continue;
}
Result = ConnI->CheckError();
if (Result == ResultState::SUCCESSFUL)
{
Fd = ConnI->Take();
return Result;
}
// Connection failed. Erase it and continue to next position
ConnI = Conns.erase(ConnI);
}
}
return Result;
}
/*}}}*/
// Connect to a given Hostname /*{{{*/
static ResultState ConnectToHostname(std::string const &Host, int const Port,
const char *const Service, int DefPort, std::unique_ptr<MethodFd> &Fd,
unsigned long const TimeOut, aptMethod *const Owner)
{
if (ConnectionAllowed(Service, Host) == false)
return ResultState::FATAL_ERROR;
// Used by getaddrinfo(); prefer port if given, else fallback to service
std::string ServiceNameOrPort = Port != 0 ? std::to_string(Port) : Service;
/* We used a cached address record.. Yes this is against the spec but
the way we have setup our rotating dns suggests that this is more
sensible */
if (LastHost != Host || LastService != ServiceNameOrPort)
{
Owner->Status(_("Connecting to %s"),Host.c_str());
// Free the old address structure
if (LastHostAddr != 0)
{
freeaddrinfo(LastHostAddr);
LastHostAddr = 0;
LastUsed = 0;
}
// We only understand SOCK_STREAM sockets.
struct addrinfo Hints;
memset(&Hints,0,sizeof(Hints));
Hints.ai_socktype = SOCK_STREAM;
Hints.ai_flags = 0;
#ifdef AI_IDN
if (_config->FindB("Acquire::Connect::IDN", true) == true)
Hints.ai_flags |= AI_IDN;
#endif
// see getaddrinfo(3): only return address if system has such a address configured
// useful if system is ipv4 only, to not get ipv6, but that fails if the system has
// no address configured: e.g. offline and trying to connect to localhost.
if (_config->FindB("Acquire::Connect::AddrConfig", true) == true)
Hints.ai_flags |= AI_ADDRCONFIG;
Hints.ai_protocol = 0;
if(_config->FindB("Acquire::ForceIPv4", false) == true)
Hints.ai_family = AF_INET;
else if(_config->FindB("Acquire::ForceIPv6", false) == true)
Hints.ai_family = AF_INET6;
else
Hints.ai_family = AF_UNSPEC;
// if we couldn't resolve the host before, we don't try now
if (bad_addr.find(Host) != bad_addr.end())
{
_error->Error(_("Could not resolve '%s'"), Host.c_str());
return ResultState::TRANSIENT_ERROR;
}
// Resolve both the host and service simultaneously
while (1)
{
int Res;
if ((Res = getaddrinfo(Host.c_str(), ServiceNameOrPort.c_str(), &Hints, &LastHostAddr)) != 0 ||
LastHostAddr == 0)
{
if (Res == EAI_NONAME || Res == EAI_SERVICE)
{
if (DefPort != 0)
{
ServiceNameOrPort = std::to_string(DefPort);
DefPort = 0;
continue;
}
bad_addr.insert(bad_addr.begin(), Host);
Owner->SetFailReason("ResolveFailure");
_error->Error(_("Could not resolve '%s'"), Host.c_str());
return ResultState::TRANSIENT_ERROR;
}
if (Res == EAI_AGAIN)
{
Owner->SetFailReason("TmpResolveFailure");
_error->Error(_("Temporary failure resolving '%s'"),
Host.c_str());
return ResultState::TRANSIENT_ERROR;
}
if (Res == EAI_SYSTEM)
_error->Errno("getaddrinfo", _("System error resolving '%s:%s'"),
Host.c_str(), ServiceNameOrPort.c_str());
else
_error->Error(_("Something wicked happened resolving '%s:%s' (%i - %s)"),
Host.c_str(), ServiceNameOrPort.c_str(), Res, gai_strerror(Res));
return ResultState::TRANSIENT_ERROR;
}
break;
}
LastHost = Host;
LastService = ServiceNameOrPort;
}
// When we have an IP rotation stay with the last IP.
auto Addresses = OrderAddresses(LastUsed != nullptr ? LastUsed : LastHostAddr);
std::list<Connection> Conns;
ResultState Result = ResultState::SUCCESSFUL;
for (auto Addr : Addresses)
{
Connection Conn(Addr, Host, Owner);
if (Conn.DoConnect() != ResultState::SUCCESSFUL)
continue;
Conns.push_back(std::move(Conn));
Result = WaitAndCheckErrors(Conns, Fd, Owner->ConfigFindI("ConnectionAttemptDelayMsec", 250), false);
if (Result == ResultState::SUCCESSFUL)
return ResultState::SUCCESSFUL;
}
if (!Conns.empty())
return WaitAndCheckErrors(Conns, Fd, TimeOut * 1000, true);
if (Result != ResultState::SUCCESSFUL)
return Result;
if (_error->PendingError() == true)
return ResultState::FATAL_ERROR;
_error->Error(_("Unable to connect to %s:%s:"), Host.c_str(), ServiceNameOrPort.c_str());
return ResultState::TRANSIENT_ERROR;
}
/*}}}*/
// Connect - Connect to a server /*{{{*/
// ---------------------------------------------------------------------
/* Performs a connection to the server (including SRV record lookup) */
ResultState Connect(std::string Host, int Port, const char *Service,
int DefPort, std::unique_ptr<MethodFd> &Fd,
unsigned long TimeOut, aptMethod *Owner)
{
if (_error->PendingError() == true)
return ResultState::FATAL_ERROR;
if (ConnectionAllowed(Service, Host) == false)
return ResultState::FATAL_ERROR;
// Used by getaddrinfo(); prefer port if given, else fallback to service
std::string ServiceNameOrPort = Port != 0 ? std::to_string(Port) : Service;
if(LastHost != Host || LastService != ServiceNameOrPort)
{
SrvRecords.clear();
if (_config->FindB("Acquire::EnableSrvRecords", true) == true)
{
GetSrvRecords(Host, DefPort, SrvRecords);
// RFC2782 defines that a lonely '.' target is an abort reason
if (SrvRecords.size() == 1 && SrvRecords[0].target.empty())
{
_error->Error("SRV records for %s indicate that "
"%s service is not available at this domain",
Host.c_str(), Service);
return ResultState::FATAL_ERROR;
}
}
}
size_t stackSize = 0;
// try to connect in the priority order of the srv records
std::string initialHost{std::move(Host)};
auto const initialPort = Port;
while(SrvRecords.empty() == false)
{
_error->PushToStack();
++stackSize;
// PopFromSrvRecs will also remove the server
auto Srv = PopFromSrvRecs(SrvRecords);
Host = Srv.target;
Port = Srv.port;
auto const ret = ConnectToHostname(Host, Port, Service, DefPort, Fd, TimeOut, Owner);
if (ret == ResultState::SUCCESSFUL)
{
while(stackSize--)
_error->RevertToStack();
return ret;
}
}
Host = std::move(initialHost);
Port = initialPort;
// we have no (good) SrvRecords for this host, connect right away
_error->PushToStack();
++stackSize;
auto const ret = ConnectToHostname(Host, Port, Service, DefPort, Fd,
TimeOut, Owner);
while(stackSize--)
if (ret == ResultState::SUCCESSFUL)
_error->RevertToStack();
else
_error->MergeWithStack();
return ret;
}
/*}}}*/
// UnwrapSocks - Handle SOCKS setup /*{{{*/
// ---------------------------------------------------------------------
/* This does socks magic */
static bool TalkToSocksProxy(int const ServerFd, std::string const &Proxy,
char const *const type, bool const ReadWrite, uint8_t *const ToFrom,
unsigned int const Size, unsigned int const Timeout)
{
if (WaitFd(ServerFd, ReadWrite, Timeout) == false)
{
if (ReadWrite)
return _error->Error("Timed out while waiting to write '%s' to proxy %s", type, URI::SiteOnly(Proxy).c_str());
else
return _error->Error("Timed out while waiting to read '%s' from proxy %s", type, URI::SiteOnly(Proxy).c_str());
}
if (ReadWrite == false)
{
if (FileFd::Read(ServerFd, ToFrom, Size) == false)
return _error->Error("Reading the %s from SOCKS proxy %s failed", type, URI::SiteOnly(Proxy).c_str());
}
else
{
if (FileFd::Write(ServerFd, ToFrom, Size) == false)
return _error->Error("Writing the %s to SOCKS proxy %s failed", type, URI::SiteOnly(Proxy).c_str());
}
return true;
}
ResultState UnwrapSocks(std::string Host, int Port, URI Proxy, std::unique_ptr<MethodFd> &Fd,
unsigned long Timeout, aptMethod *Owner)
{
/* We implement a very basic SOCKS5 client here complying mostly to RFC1928 expect
* for not offering GSSAPI auth which is a must (we only do no or user/pass auth).
* We also expect the SOCKS5 server to do hostname lookup (aka socks5h) */
std::string const ProxyInfo = URI::SiteOnly(Proxy);
Owner->Status(_("Connecting to %s (%s)"), "SOCKS5h proxy", ProxyInfo.c_str());
#define APT_WriteOrFail(TYPE, DATA, LENGTH) \
if (TalkToSocksProxy(Fd->Fd(), ProxyInfo, TYPE, true, DATA, LENGTH, Timeout) == false) \
return ResultState::TRANSIENT_ERROR
#define APT_ReadOrFail(TYPE, DATA, LENGTH) \
if (TalkToSocksProxy(Fd->Fd(), ProxyInfo, TYPE, false, DATA, LENGTH, Timeout) == false) \
return ResultState::TRANSIENT_ERROR
if (Host.length() > 255)
{
_error->Error("Can't use SOCKS5h as hostname %s is too long!", Host.c_str());
return ResultState::FATAL_ERROR;
}
if (Proxy.User.length() > 255 || Proxy.Password.length() > 255)
{
_error->Error("Can't use user&pass auth as they are too long (%lu and %lu) for the SOCKS5!", Proxy.User.length(), Proxy.Password.length());
return ResultState::FATAL_ERROR;
}
if (Proxy.User.empty())
{
uint8_t greeting[] = {0x05, 0x01, 0x00};
APT_WriteOrFail("greet-1", greeting, sizeof(greeting));
}
else
{
uint8_t greeting[] = {0x05, 0x02, 0x00, 0x02};
APT_WriteOrFail("greet-2", greeting, sizeof(greeting));
}
uint8_t greeting[2];
APT_ReadOrFail("greet back", greeting, sizeof(greeting));
if (greeting[0] != 0x05)
{
_error->Error("SOCKS proxy %s greets back with wrong version: %d", ProxyInfo.c_str(), greeting[0]);
return ResultState::FATAL_ERROR;
}
if (greeting[1] == 0x00)
; // no auth has no method-dependent sub-negotiations
else if (greeting[1] == 0x02)
{
if (Proxy.User.empty())
{
_error->Error("SOCKS proxy %s negotiated user&pass auth, but we had not offered it!", ProxyInfo.c_str());
return ResultState::FATAL_ERROR;
}
// user&pass auth sub-negotiations are defined by RFC1929
std::vector<uint8_t> auth = {{0x01, static_cast<uint8_t>(Proxy.User.length())}};
std::copy(Proxy.User.begin(), Proxy.User.end(), std::back_inserter(auth));
auth.push_back(static_cast<uint8_t>(Proxy.Password.length()));
std::copy(Proxy.Password.begin(), Proxy.Password.end(), std::back_inserter(auth));
APT_WriteOrFail("user&pass auth", auth.data(), auth.size());
uint8_t authstatus[2];
APT_ReadOrFail("auth report", authstatus, sizeof(authstatus));
if (authstatus[0] != 0x01)
{
_error->Error("SOCKS proxy %s auth status response with wrong version: %d", ProxyInfo.c_str(), authstatus[0]);
return ResultState::FATAL_ERROR;
}
if (authstatus[1] != 0x00)
{
_error->Error("SOCKS proxy %s reported authorization failure: username or password incorrect? (%d)", ProxyInfo.c_str(), authstatus[1]);
return ResultState::FATAL_ERROR;
}
}
else
{
_error->Error("SOCKS proxy %s greets back having not found a common authorization method: %d", ProxyInfo.c_str(), greeting[1]);
return ResultState::FATAL_ERROR;
}
union {
uint16_t *i;
uint8_t *b;
} portu;
uint16_t port = htons(static_cast<uint16_t>(Port));
portu.i = &port;
std::vector<uint8_t> request = {{0x05, 0x01, 0x00, 0x03, static_cast<uint8_t>(Host.length())}};
std::copy(Host.begin(), Host.end(), std::back_inserter(request));
request.push_back(portu.b[0]);
request.push_back(portu.b[1]);
APT_WriteOrFail("request", request.data(), request.size());
uint8_t response[4];
APT_ReadOrFail("first part of response", response, sizeof(response));
if (response[0] != 0x05)
{
_error->Error("SOCKS proxy %s response with wrong version: %d", ProxyInfo.c_str(), response[0]);
return ResultState::FATAL_ERROR;
}
if (response[2] != 0x00)
{
_error->Error("SOCKS proxy %s has unexpected non-zero reserved field value: %d", ProxyInfo.c_str(), response[2]);
return ResultState::FATAL_ERROR;
}
std::string bindaddr;
if (response[3] == 0x01) // IPv4 address
{
uint8_t ip4port[6];
APT_ReadOrFail("IPv4+Port of response", ip4port, sizeof(ip4port));
portu.b[0] = ip4port[4];
portu.b[1] = ip4port[5];
port = ntohs(*portu.i);
strprintf(bindaddr, "%d.%d.%d.%d:%d", ip4port[0], ip4port[1], ip4port[2], ip4port[3], port);
}
else if (response[3] == 0x03) // hostname
{
uint8_t namelength;
APT_ReadOrFail("hostname length of response", &namelength, 1);
uint8_t hostname[namelength + 2];
APT_ReadOrFail("hostname of response", hostname, sizeof(hostname));
portu.b[0] = hostname[namelength];
portu.b[1] = hostname[namelength + 1];
port = ntohs(*portu.i);
hostname[namelength] = '\0';
strprintf(bindaddr, "%s:%d", hostname, port);
}
else if (response[3] == 0x04) // IPv6 address
{
uint8_t ip6port[18];
APT_ReadOrFail("IPv6+port of response", ip6port, sizeof(ip6port));
portu.b[0] = ip6port[16];
portu.b[1] = ip6port[17];
port = ntohs(*portu.i);
strprintf(bindaddr, "[%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X:%02X%02X]:%d",
ip6port[0], ip6port[1], ip6port[2], ip6port[3], ip6port[4], ip6port[5], ip6port[6], ip6port[7],
ip6port[8], ip6port[9], ip6port[10], ip6port[11], ip6port[12], ip6port[13], ip6port[14], ip6port[15],
port);
}
else
{
_error->Error("SOCKS proxy %s destination address is of unknown type: %d",
ProxyInfo.c_str(), response[3]);
return ResultState::FATAL_ERROR;
}
if (response[1] != 0x00)
{
char const *errstr = nullptr;
auto errcode = response[1];
bool Transient = false;
// Tor error reporting can be a bit arcane, lets try to detect & fix it up
if (bindaddr == "0.0.0.0:0")
{
auto const lastdot = Host.rfind('.');
if (lastdot == std::string::npos || Host.substr(lastdot) != ".onion")
;
else if (errcode == 0x01)
{
auto const prevdot = Host.rfind('.', lastdot - 1);
if (prevdot == std::string::npos && (lastdot == 16 || lastdot == 56))
; // valid .onion address
else if (prevdot != std::string::npos && ((lastdot - prevdot) == 17 || (lastdot - prevdot) == 57))
; // valid .onion address with subdomain(s)
else
{
errstr = "Invalid hostname: onion service name must be either 16 or 56 characters long";
Owner->SetFailReason("SOCKS");
}
}
// in all likelihood the service is either down or the address has
// a typo and so "Host unreachable" is the better understood error
// compared to the technically correct "TLL expired".
else if (errcode == 0x06)
errcode = 0x04;
}
if (errstr == nullptr)
{
switch (errcode)
{
case 0x01:
errstr = "general SOCKS server failure";
Owner->SetFailReason("SOCKS");
break;
case 0x02:
errstr = "connection not allowed by ruleset";
Owner->SetFailReason("SOCKS");
break;
case 0x03:
errstr = "Network unreachable";
Owner->SetFailReason("ConnectionTimedOut");
Transient = true;
break;
case 0x04:
errstr = "Host unreachable";
Owner->SetFailReason("ConnectionTimedOut");
Transient = true;
break;
case 0x05:
errstr = "Connection refused";
Owner->SetFailReason("ConnectionRefused");
Transient = true;
break;
case 0x06:
errstr = "TTL expired";
Owner->SetFailReason("Timeout");
Transient = true;
break;
case 0x07:
errstr = "Command not supported";
Owner->SetFailReason("SOCKS");
break;
case 0x08:
errstr = "Address type not supported";
Owner->SetFailReason("SOCKS");
break;
default:
errstr = "Unknown error";
Owner->SetFailReason("SOCKS");
break;
}
}
_error->Error("SOCKS proxy %s could not connect to %s (%s) due to: %s (%d)",
ProxyInfo.c_str(), Host.c_str(), bindaddr.c_str(), errstr, response[1]);
return Transient ? ResultState::TRANSIENT_ERROR : ResultState::FATAL_ERROR;
}
else if (Owner->DebugEnabled())
ioprintf(std::clog, "http: SOCKS proxy %s connection established to %s (%s)\n",
ProxyInfo.c_str(), Host.c_str(), bindaddr.c_str());
if (WaitFd(Fd->Fd(), true, Timeout) == false)
{
_error->Error("SOCKS proxy %s reported connection to %s (%s), but timed out",
ProxyInfo.c_str(), Host.c_str(), bindaddr.c_str());
return ResultState::TRANSIENT_ERROR;
}
#undef APT_ReadOrFail
#undef APT_WriteOrFail
return ResultState::SUCCESSFUL;
}
// UnwrapTLS - Handle TLS connections /*{{{*/
// ---------------------------------------------------------------------
/* Performs a TLS handshake on the socket */
#define null_error(...) (_error->Error(__VA_ARGS__), nullptr)
#define ssl_strerr() ERR_error_string(ERR_get_error(), nullptr)
struct TlsFd final : public MethodFd
{
std::unique_ptr<MethodFd> UnderlyingFd{};
SSL *ssl{};
std::string hostname{};
unsigned long Timeout{};
bool broken{false};
int Fd() override { return UnderlyingFd ? UnderlyingFd->Fd() : -1; }
ssize_t Read(void *buf, size_t count) override
{
assert(ssl);
return HandleError(SSL_read(ssl, buf, count));
}
ssize_t Write(void *buf, size_t count) override
{
assert(ssl);
return HandleError(SSL_write(ssl, buf, count));
}
ssize_t HandleError(ssize_t r)
{
assert(ssl);
if (r > 0)
return r;
auto err = SSL_get_error(ssl, r);
switch (err)
{
case SSL_ERROR_WANT_READ:
case SSL_ERROR_WANT_WRITE:
errno = EAGAIN;
return -1;
case SSL_ERROR_ZERO_RETURN:
// Remote host has closed connection
errno = 0;
return 0;
case SSL_ERROR_SYSCALL:
broken = true;
_error->Errno("openssl", "OpenSSL system call error: %s\n", ssl_strerr());
return -1;
case SSL_ERROR_SSL:
broken = true;
errno = EIO;
_error->Error("OpenSSL error: %s\n", ssl_strerr());
return -1;
default:
broken = true;
errno = EIO;
_error->Error("Unexpected OpenSSL error: %s\n", ssl_strerr());
return -1;
}
}
int Close() override
{
int res = 0; // 0 or 1 are success
int lower = 0; // 0 is success
if (ssl)
{
if (not broken && res)
res = SSL_shutdown(ssl);
if (res < 0)
HandleError(res);
SSL_free(ssl);
}
ssl = nullptr;
if (UnderlyingFd)
lower = UnderlyingFd->Close();
UnderlyingFd = nullptr;
// Return -1 on failure, 0 on success
return res < 0 || lower < 0 ? -1 : 0;
}
bool HasPending() override
{
assert(ssl);
// SSL_has_pending() can return 1 even if there are no actual bytes to read
// post decoding, so we need to SSL_peek() too to see if there are actual
// bytes as otherwise we end up busy looping (tested by DE -> AU https connection)
char buf;
return SSL_has_pending(ssl) && SSL_peek(ssl, &buf, 1) > 0;
}
};
static BIO_METHOD *NewBioMethod()
{
BIO_METHOD *m = BIO_meth_new(BIO_TYPE_MEM, "OpenSSL APT BIO method");
if (not m)
{
_error->Error("SSL connection failed: %s - %s", ssl_strerr(), strerror(errno));
return nullptr;
}
BIO_meth_set_ctrl(m, [](BIO *, int, long, void *) -> long
{ return 1; });
BIO_meth_set_write(m, [](BIO *bio, const char *buf, int size) -> int
{
auto p = BIO_get_data(bio);
auto res = reinterpret_cast<MethodFd *>(p)->Write((void*)buf, size);
if (errno == EAGAIN)
BIO_set_retry_write(bio);
return res; });
BIO_meth_set_read(m, [](BIO *bio, char *buf, int size) -> int
{
auto p = BIO_get_data(bio);
auto res = reinterpret_cast<MethodFd *>(p)->Read(buf, size);
if (errno == EAGAIN)
BIO_set_retry_read(bio);
return res; });
return m;
}
static SSL_CTX *GetContextForHost(std::string const &host, aptConfigWrapperForMethods const *const OwnerConf)
{
static std::string lastHost;
static SSL_CTX *ctx;
auto Debug = OwnerConf->DebugEnabled();
if (lastHost == host)
{
if (Debug)
std::clog << "Reusing context for " << host << std::endl;
return ctx;
}
if (Debug)
std::clog << "Creating context for " << host << std::endl;
// Check unsupported options first, maybe we reuse the host context later, who knows
if (not OwnerConf->ConfigFind("IssuerCert", "").empty())
return null_error("The option '%s' is not supported anymore", "IssuerCert");
if (not OwnerConf->ConfigFind("SslForceVersion", "").empty())
return null_error("The option '%s' is not supported anymore", "SslForceVersion");
// Delete the existing context and render it unusable
lastHost = "";
SSL_CTX_free(ctx);
// We set the context here, but lastHost at the end to only allow reuse of fully initialized contexts
ctx = SSL_CTX_new(TLS_client_method());
if (ctx == nullptr)
return null_error("Could not create new SSL context: %s", ssl_strerr());
// Load the certificate authorities, either custom or default ones
if (auto const fileinfo = OwnerConf->ConfigFind("CaInfo", ""); not fileinfo.empty())
{
if (auto res = SSL_CTX_load_verify_file(ctx, fileinfo.c_str()); res != 1)
return null_error("Could not load certificates from %s (CaInfo option): %s", fileinfo.c_str(), ssl_strerr());
}
else if (auto err = SSL_CTX_set_default_verify_paths(ctx); err != 1)
return null_error("Could not load certificates: %s", ssl_strerr());
// Client certificate setup, such that clients can authenticate to the server
if (auto const cert = OwnerConf->ConfigFind("SslCert", ""); not cert.empty())
if (auto res = SSL_CTX_use_certificate_chain_file(ctx, cert.c_str()); res != 1)
return null_error("Could not load client certificate (%s, SslCert option): %s", cert.c_str(), ssl_strerr());
if (auto const key = OwnerConf->ConfigFind("SslKey", ""); not key.empty())
if (auto res = SSL_CTX_use_PrivateKey_file(ctx, key.c_str(), SSL_FILETYPE_PEM); res != 1)
return null_error("Could not load client or key (%s, SslKey option): %s", key.c_str(), ssl_strerr()), nullptr;
// Custom certificate revocation lists. We surely support all the niche cases.
if (auto const crlfile = OwnerConf->ConfigFind("CrlFile", ""); not crlfile.empty())
{
// tell OpenSSL where to find CRL file that is used to check certificate revocation.
// lifted from curl:
// Copyright (c) 1996 - 2023, Daniel Stenberg, <daniel@haxx.se>, and many
// contributors, see the THANKS file.
auto lookup = X509_STORE_add_lookup(SSL_CTX_get_cert_store(ctx),
X509_LOOKUP_file());
if (not lookup || not X509_load_crl_file(lookup, crlfile.c_str(), X509_FILETYPE_PEM))
return null_error("Could not load custom certificate revocation list %s (CrlFile option): %s", crlfile.c_str(), ssl_strerr());
/* Everything is fine. */
X509_STORE_set_flags(SSL_CTX_get_cert_store(ctx),
X509_V_FLAG_CRL_CHECK | X509_V_FLAG_CRL_CHECK_ALL);
}
lastHost = host;
return ctx;
}
ResultState UnwrapTLS(std::string const &Host, std::unique_ptr<MethodFd> &Fd,
unsigned long const Timeout, aptMethod *const /*Owner*/,
aptConfigWrapperForMethods const *const OwnerConf)
{
if (_config->FindB("Acquire::AllowTLS", true) == false)
{
_error->Error("TLS support has been disabled: Acquire::AllowTLS is false.");
return ResultState::FATAL_ERROR;
}
TlsFd *tlsFd = new TlsFd();
tlsFd->hostname = Host;
tlsFd->Timeout = Timeout;
if (auto ctx = GetContextForHost(Host, OwnerConf))
tlsFd->ssl = SSL_new(ctx);
else
return ResultState::FATAL_ERROR;
FdFd *fdfd = dynamic_cast<FdFd *>(Fd.get());
if (fdfd != nullptr)
{
SSL_set_fd(tlsFd->ssl, fdfd->fd);
}
else
{
static auto m = NewBioMethod();
if (m == nullptr)
return ResultState::FATAL_ERROR;
auto bio = BIO_new(m);
if (bio == nullptr)
return ResultState::FATAL_ERROR;
BIO_set_data(bio, Fd.get());
BIO_up_ref(bio); // the following take one reference each
SSL_set0_rbio(tlsFd->ssl, bio);
SSL_set0_wbio(tlsFd->ssl, bio);
}
if (OwnerConf->ConfigFindB("Verify-Peer", true))
{
SSL_set_verify(tlsFd->ssl, SSL_VERIFY_PEER, nullptr);
if (auto res = SSL_set1_host(tlsFd->ssl, OwnerConf->ConfigFindB("Verify-Host", true) ? tlsFd->hostname.c_str() : nullptr); res != 1)
{
_error->Error("Could not set hostname: %s", ssl_strerr());
return ResultState::FATAL_ERROR;
}
}
// set SNI only if the hostname is really a name and not an address
{
struct in_addr addr4;
struct in6_addr addr6;
if (inet_pton(AF_INET, tlsFd->hostname.c_str(), &addr4) == 1 ||
inet_pton(AF_INET6, tlsFd->hostname.c_str(), &addr6) == 1)
/* not a host name */;
else if (auto res = SSL_set_tlsext_host_name(tlsFd->ssl, tlsFd->hostname.c_str()); res != 1)
{
_error->Error("Could not set host name %s to indicate to server: %s", tlsFd->hostname.c_str(), ssl_strerr());
return ResultState::FATAL_ERROR;
}
}
while (true)
{
auto res = SSL_connect(tlsFd->ssl);
if (res == 1)
break;
switch (auto error = SSL_get_error(tlsFd->ssl, res))
{
case SSL_ERROR_WANT_READ:
case SSL_ERROR_WANT_WRITE:
if (not WaitFd(Fd->Fd(), error == SSL_ERROR_WANT_WRITE, Timeout))
{
_error->Errno("select", "Could not wait for server fd");
return ResultState::TRANSIENT_ERROR;
}
break;
default:
_error->Error("SSL connection failed: %s / %s", ssl_strerr(), strerror(errno));
return ResultState::TRANSIENT_ERROR;
}
}
// Set the FD now, so closing it works reliably.
tlsFd->UnderlyingFd = std::move(Fd);
Fd.reset(tlsFd);
return ResultState::SUCCESSFUL;
}
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