sshauthsock.cpp

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// SPDX-FileCopyrightText: 2014 Anne Jan Brouwer
// SPDX-License-Identifier: GPL-3.0-or-later
#include "sshauthsock.h"
#include "executor.h"
#include <QFileInfo>
#include <QProcessEnvironment>
#ifndef Q_OS_WIN
#include <sys/stat.h>
#endif
 
#include "qtpasslogging.h"
 
namespace {
auto isSshAgentReachable(const QString &candidate) -> bool {
  if (candidate.isEmpty()) {
    return false;
  }
  // Build a minimal env that overrides SSH_AUTH_SOCK without polluting the
  // parent process. systemEnvironment() captures whatever was set when
  // QtPass started, then we override the one var of interest.
  QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
  env.insert(QStringLiteral("SSH_AUTH_SOCK"), candidate);
  QString out;
  QString err;
  const int exitCode = Executor::executeBlocking(
      env, QStringLiteral("ssh-add"), {QStringLiteral("-l")}, &out, &err);
  // OpenSSH ssh-add(1) exit codes: 0 = success / has keys, 1 = no
  // identities present, 2 = couldn't open a connection. Anything else is
  // also treated as unreachable (e.g. ssh-add not on PATH).
  return exitCode == 0 || exitCode == 1;
}
auto adoptSocketFrom(const QString &program, const QStringList &args,
                     const char *source) -> bool {
  QString out;
  QString err;
  if (Executor::executeBlocking(program, args, &out, &err) != 0) {
    return false;
  }
  const QString socket = out.trimmed();
  if (socket.isEmpty()) {
    return false;
  }
  if (!isSshAgentReachable(socket)) {
    qCDebug(lcQtPass) << "SshAuthSock::initialise():" << source << "reported"
                      << socket << "but ssh-add -l rejected it; not adopting";
    return false;
  }
  qputenv("SSH_AUTH_SOCK", socket.toUtf8());
  qCDebug(lcQtPass) << "SshAuthSock::initialise(): set from" << source << ":"
                    << socket;
  return true;
}
 
} // namespace
 
auto SshAuthSock::overrideStatus(const QString &path) -> OverrideStatus {
  const QFileInfo fi(path);
  if (!fi.exists()) {
    return OverrideStatus::DoesNotExist;
  }
  if (!fi.isReadable()) {
    return OverrideStatus::NotReadable;
  }
#ifdef Q_OS_UNIX
  // S_ISSOCK isn't exposed by QFileInfo; go through stat(2). On Windows
  // ssh-agent uses a named pipe (\\.\pipe\openssh-ssh-agent.<sid>) and the
  // socket check would always fail, so skip it there — exists + readable is
  // the best we can do.
  struct stat st{};
  if (::stat(path.toLocal8Bit().constData(), &st) != 0 ||
      !S_ISSOCK(st.st_mode)) {
    return OverrideStatus::NotUnixDomainSocket;
  }
#endif
  return OverrideStatus::Valid;
}
 
// The rules are in the header. All probes go through
// Executor::executeBlocking with no timeout or cancel flag, so each one
// waits for its child (gpgconf, ssh-add -l) however long that takes. Any
// failure is silently absorbed (the user just doesn't get the auto-fix).
void SshAuthSock::initialise(const QString &override) {
  // Honour any value already in the environment — terminal launches,
  // explicit `.desktop` Exec= overrides, and parent-process exports must win.
  if (!qgetenv("SSH_AUTH_SOCK").isEmpty()) {
    return;
  }
 
  // Manual override from settings takes precedence over auto-probe.
  if (!override.isEmpty()) {
    qputenv("SSH_AUTH_SOCK", override.toUtf8());
    qCDebug(lcQtPass)
        << "SshAuthSock::initialise(): set from settings override:" << override;
    return;
  }
 
  // Auto-probe via gpgconf (canonical for gpg-agent's SSH support).
  if (adoptSocketFrom(
          QStringLiteral("gpgconf"),
          {QStringLiteral("--list-dirs"), QStringLiteral("agent-ssh-socket")},
          "gpgconf")) {
    return;
  }
#ifdef Q_OS_MACOS
  // On macOS, GUI-launched apps may have SSH_AUTH_SOCK in launchd's
  // per-session environment but not in the inherited process env.
  adoptSocketFrom(QStringLiteral("launchctl"),
                  {QStringLiteral("getenv"), QStringLiteral("SSH_AUTH_SOCK")},
                  "launchctl");
#endif
}