forked from lix-project/lix
147 lines
4 KiB
C++
147 lines
4 KiB
C++
#include "ssh.hh"
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namespace nix {
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SSHMaster::SSHMaster(const std::string & host, const std::string & keyFile, const std::string & sshPublicHostKey, bool useMaster, bool compress, int logFD)
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: host(host)
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, fakeSSH(host == "localhost")
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, keyFile(keyFile)
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, sshPublicHostKey(sshPublicHostKey)
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, useMaster(useMaster && !fakeSSH)
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, compress(compress)
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, logFD(logFD)
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{
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if (host == "" || hasPrefix(host, "-"))
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throw Error("invalid SSH host name '%s'", host);
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auto state(state_.lock());
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state->tmpDir = std::make_unique<AutoDelete>(createTempDir("", "nix", true, true, 0700));
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}
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void SSHMaster::addCommonSSHOpts(Strings & args)
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{
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auto state(state_.lock());
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for (auto & i : tokenizeString<Strings>(getEnv("NIX_SSHOPTS").value_or("")))
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args.push_back(i);
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if (!keyFile.empty())
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args.insert(args.end(), {"-i", keyFile});
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if (!sshPublicHostKey.empty()) {
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Path fileName = (Path) *state->tmpDir + "/host-key";
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auto p = host.rfind("@");
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std::string thost = p != std::string::npos ? std::string(host, p + 1) : host;
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writeFile(fileName, thost + " " + base64Decode(sshPublicHostKey) + "\n");
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args.insert(args.end(), {"-oUserKnownHostsFile=" + fileName});
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}
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if (compress)
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args.push_back("-C");
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}
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std::unique_ptr<SSHMaster::Connection> SSHMaster::startCommand(const std::string & command)
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{
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Path socketPath = startMaster();
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Pipe in, out;
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in.create();
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out.create();
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auto conn = std::make_unique<Connection>();
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ProcessOptions options;
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options.dieWithParent = false;
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conn->sshPid = startProcess([&]() {
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restoreProcessContext();
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close(in.writeSide.get());
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close(out.readSide.get());
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if (dup2(in.readSide.get(), STDIN_FILENO) == -1)
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throw SysError("duping over stdin");
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if (dup2(out.writeSide.get(), STDOUT_FILENO) == -1)
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throw SysError("duping over stdout");
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if (logFD != -1 && dup2(logFD, STDERR_FILENO) == -1)
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throw SysError("duping over stderr");
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Strings args;
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if (fakeSSH) {
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args = { "bash", "-c" };
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} else {
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args = { "ssh", host.c_str(), "-x", "-a" };
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addCommonSSHOpts(args);
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if (socketPath != "")
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args.insert(args.end(), {"-S", socketPath});
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if (verbosity >= lvlChatty)
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args.push_back("-v");
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}
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args.push_back(command);
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execvp(args.begin()->c_str(), stringsToCharPtrs(args).data());
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// could not exec ssh/bash
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throw SysError("unable to execute '%s'", args.front());
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}, options);
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in.readSide = -1;
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out.writeSide = -1;
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conn->out = std::move(out.readSide);
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conn->in = std::move(in.writeSide);
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return conn;
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}
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Path SSHMaster::startMaster()
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{
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if (!useMaster) return "";
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auto state(state_.lock());
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if (state->sshMaster != -1) return state->socketPath;
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state->socketPath = (Path) *state->tmpDir + "/ssh.sock";
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Pipe out;
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out.create();
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ProcessOptions options;
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options.dieWithParent = false;
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state->sshMaster = startProcess([&]() {
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restoreProcessContext();
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close(out.readSide.get());
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if (dup2(out.writeSide.get(), STDOUT_FILENO) == -1)
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throw SysError("duping over stdout");
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Strings args =
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{ "ssh", host.c_str(), "-M", "-N", "-S", state->socketPath
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, "-o", "LocalCommand=echo started"
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, "-o", "PermitLocalCommand=yes"
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};
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if (verbosity >= lvlChatty)
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args.push_back("-v");
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addCommonSSHOpts(args);
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execvp(args.begin()->c_str(), stringsToCharPtrs(args).data());
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throw SysError("unable to execute '%s'", args.front());
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}, options);
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out.writeSide = -1;
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std::string reply;
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try {
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reply = readLine(out.readSide.get());
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} catch (EndOfFile & e) { }
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if (reply != "started")
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throw Error("failed to start SSH master connection to '%s'", host);
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return state->socketPath;
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}
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}
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