diff options
| -rw-r--r-- | doc/guix.texi | 55 | ||||
| -rw-r--r-- | nix/nix-daemon/guix-daemon.cc | 152 | ||||
| -rw-r--r-- | nix/nix-daemon/nix-daemon.cc | 283 | ||||
| -rw-r--r-- | tests/guix-daemon.sh | 12 |
4 files changed, 327 insertions, 175 deletions
diff --git a/doc/guix.texi b/doc/guix.texi index ee9f80ef4d..729ec081be 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -1258,12 +1258,47 @@ Assume @var{system} as the current system type. By default it is the architecture/kernel pair found at configure time, such as @code{x86_64-linux}. -@item --listen=@var{socket} -Listen for connections on @var{socket}, the file name of a Unix-domain -socket. The default socket is -@file{@var{localstatedir}/daemon-socket/socket}. This option is only -useful in exceptional circumstances, such as if you need to run several -daemons on the same machine. +@item --listen=@var{endpoint} +Listen for connections on @var{endpoint}. @var{endpoint} is interpreted +as the file name of a Unix-domain socket if it starts with +@code{/} (slash sign). Otherwise, @var{endpoint} is interpreted as a +host name or host name and port to listen to. Here are a few examples: + +@table @code +@item --listen=/gnu/var/daemon +Listen for connections on the @file{/gnu/var/daemon} Unix-domain socket, +creating it if needed. + +@item --listen=localhost +@cindex daemon, remote access +@cindex remote access to the daemon +@cindex daemon, cluster setup +@cindex clusters, daemon setup +Listen for TCP connections on the network interface corresponding to +@code{localhost}, on port 44146. + +@item --listen=128.0.0.42:1234 +Listen for TCP connections on the network interface corresponding to +@code{128.0.0.42}, on port 1234. +@end table + +This option can be repeated multiple times, in which case +@command{guix-daemon} accepts connections on all the specified +endpoints. Users can tell client commands what endpoint to connect to +by setting the @code{GUIX_DAEMON_SOCKET} environment variable +(@pxref{The Store, @code{GUIX_DAEMON_SOCKET}}). + +@quotation Note +The daemon protocol is @emph{unauthenticated and unencrypted}. Using +@code{--listen=@var{host}} is suitable on local networks, such as +clusters, where only trusted nodes may connect to the build daemon. In +other cases where remote access to the daemon is needed, we recommend +using Unix-domain sockets along with SSH. +@end quotation + +When @code{--listen} is omitted, @command{guix-daemon} listens for +connections on the Unix-domain socket located at +@file{@var{localstatedir}/daemon-socket/socket}. @end table @@ -3769,6 +3804,10 @@ These are for Unix-domain sockets. @file{/var/guix/daemon-socket/socket}. @item guix +@cindex daemon, remote access +@cindex remote access to the daemon +@cindex daemon, cluster setup +@cindex clusters, daemon setup These URIs denote connections over TCP/IP, without encryption nor authentication of the remote host. The URI must specify the host name and optionally a port number (by default port 44146 is used): @@ -3781,6 +3820,10 @@ This setup is suitable on local networks, such as clusters, where only trusted nodes may connect to the build daemon at @code{master.guix.example.org}. +The @code{--listen} option of @command{guix-daemon} can be used to +instruct it to listen for TCP connections (@pxref{Invoking guix-daemon, +@code{--listen}}). + @item ssh @cindex SSH access to build daemons These URIs allow you to connect to a remote daemon over diff --git a/nix/nix-daemon/guix-daemon.cc b/nix/nix-daemon/guix-daemon.cc index 0d9c33d1d2..7963358202 100644 --- a/nix/nix-daemon/guix-daemon.cc +++ b/nix/nix-daemon/guix-daemon.cc @@ -1,5 +1,6 @@ /* GNU Guix --- Functional package management for GNU Copyright (C) 2012, 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org> + Copyright (C) 2006, 2010, 2012, 2014 Eelco Dolstra <e.dolstra@tudelft.nl> This file is part of GNU Guix. @@ -30,8 +31,12 @@ #include <unistd.h> #include <sys/types.h> #include <sys/stat.h> +#include <sys/socket.h> +#include <sys/un.h> +#include <netdb.h> #include <strings.h> #include <exception> +#include <iostream> #include <libintl.h> #include <locale.h> @@ -43,7 +48,7 @@ char **argvSaved; using namespace nix; /* Entry point in `nix-daemon.cc'. */ -extern void run (Strings args); +extern void run (const std::vector<int> &); /* Command-line options. */ @@ -149,6 +154,12 @@ to live outputs") }, }; +/* Default port for '--listen' on TCP/IP. */ +#define DEFAULT_GUIX_PORT "44146" + +/* List of '--listen' options. */ +static std::list<std::string> listen_options; + /* Convert ARG to a Boolean value, or throw an error if it does not denote a Boolean. */ static bool @@ -217,15 +228,7 @@ parse_opt (int key, char *arg, struct argp_state *state) settings.keepLog = false; break; case GUIX_OPT_LISTEN: - try - { - settings.nixDaemonSocketFile = canonPath (arg); - } - catch (std::exception &e) - { - fprintf (stderr, _("error: %s\n"), e.what ()); - exit (EXIT_FAILURE); - } + listen_options.push_back (arg); break; case GUIX_OPT_SUBSTITUTE_URLS: settings.set ("substitute-urls", arg); @@ -276,13 +279,134 @@ static const struct argp argp = guix_textdomain }; + +static int +open_unix_domain_socket (const char *file) +{ + /* Create and bind to a Unix domain socket. */ + AutoCloseFD fdSocket = socket (PF_UNIX, SOCK_STREAM, 0); + if (fdSocket == -1) + throw SysError (_("cannot create Unix domain socket")); + + createDirs (dirOf (file)); + + /* Urgh, sockaddr_un allows path names of only 108 characters. + So chdir to the socket directory so that we can pass a + relative path name. */ + if (chdir (dirOf (file).c_str ()) == -1) + throw SysError (_("cannot change current directory")); + Path fileRel = "./" + baseNameOf (file); + + struct sockaddr_un addr; + addr.sun_family = AF_UNIX; + if (fileRel.size () >= sizeof (addr.sun_path)) + throw Error (format (_("socket file name '%1%' is too long")) % fileRel); + strcpy (addr.sun_path, fileRel.c_str ()); + + unlink (file); + + /* Make sure that the socket is created with 0666 permission + (everybody can connect --- provided they have access to the + directory containing the socket). */ + mode_t oldMode = umask (0111); + int res = bind (fdSocket, (struct sockaddr *) &addr, sizeof addr); + umask (oldMode); + if (res == -1) + throw SysError (format (_("cannot bind to socket '%1%'")) % file); + + if (chdir ("/") == -1) /* back to the root */ + throw SysError (_("cannot change current directory")); + + if (listen (fdSocket, 5) == -1) + throw SysError (format (_("cannot listen on socket '%1%'")) % file); + + return fdSocket.borrow (); +} + +/* Return a listening socket for ADDRESS, which has the given LENGTH. */ +static int +open_inet_socket (const struct sockaddr *address, socklen_t length) +{ + AutoCloseFD fd = socket (address->sa_family, SOCK_STREAM, 0); + if (fd == -1) + throw SysError (_("cannot create TCP socket")); + + int res = bind (fd, address, length); + if (res == -1) + throw SysError (_("cannot bind TCP socket")); + + if (listen (fd, 5) == -1) + throw SysError (format (_("cannot listen on TCP socket"))); + + return fd.borrow (); +} + +/* Return a list of file descriptors of listening sockets. */ +static std::vector<int> +listening_sockets (const std::list<std::string> &options) +{ + std::vector<int> result; + + if (options.empty ()) + { + /* Open the default Unix-domain socket. */ + auto fd = open_unix_domain_socket (settings.nixDaemonSocketFile.c_str ()); + result.push_back (fd); + return result; + } + + /* Open the user-specified sockets. */ + for (const std::string& option: options) + { + if (option[0] == '/') + { + /* Assume OPTION is the file name of a Unix-domain socket. */ + settings.nixDaemonSocketFile = canonPath (option); + int fd = + open_unix_domain_socket (settings.nixDaemonSocketFile.c_str ()); + result.push_back (fd); + } + else + { + /* Assume OPTIONS has the form "HOST" or "HOST:PORT". */ + auto colon = option.find_last_of (":"); + auto host = colon == std::string::npos + ? option : option.substr (0, colon); + auto port = colon == std::string::npos + ? DEFAULT_GUIX_PORT + : option.substr (colon + 1, option.size () - colon - 1); + + struct addrinfo *res, hints; + + memset (&hints, '\0', sizeof hints); + hints.ai_socktype = SOCK_STREAM; + hints.ai_flags = AI_NUMERICSERV | AI_ADDRCONFIG; + + int err = getaddrinfo (host.c_str(), port.c_str (), + &hints, &res); + + if (err != 0) + throw Error(format ("failed to look up '%1%': %2%") + % option % gai_strerror (err)); + + printMsg (lvlDebug, format ("listening on '%1%', port '%2%'") + % host % port); + + /* XXX: Pick the first result, RES. */ + result.push_back (open_inet_socket (res->ai_addr, + res->ai_addrlen)); + + freeaddrinfo (res); + } + } + + return result; +} int main (int argc, char *argv[]) { - static const Strings nothing; - setlocale (LC_ALL, ""); bindtextdomain (guix_textdomain, LOCALEDIR); textdomain (guix_textdomain); @@ -359,6 +483,8 @@ main (int argc, char *argv[]) argp_parse (&argp, argc, argv, 0, 0, 0); + auto sockets = listening_sockets (listen_options); + /* Effect all the changes made via 'settings.set'. */ settings.update (); @@ -402,7 +528,7 @@ using `--build-users-group' is highly recommended\n")); printMsg (lvlDebug, format ("listening on `%1%'") % settings.nixDaemonSocketFile); - run (nothing); + run (sockets); } catch (std::exception &e) { diff --git a/nix/nix-daemon/nix-daemon.cc b/nix/nix-daemon/nix-daemon.cc index 79580ffb48..3d8e909901 100644 --- a/nix/nix-daemon/nix-daemon.cc +++ b/nix/nix-daemon/nix-daemon.cc @@ -18,6 +18,7 @@ #include <sys/stat.h> #include <sys/socket.h> #include <sys/un.h> +#include <arpa/inet.h> #include <fcntl.h> #include <errno.h> #include <pwd.h> @@ -809,151 +810,87 @@ static void setSigChldAction(bool autoReap) } -bool matchUser(const string & user, const string & group, const Strings & users) +/* Accept a connection on FDSOCKET and fork a server process to process the + new connection. */ +static void acceptConnection(int fdSocket) { - if (find(users.begin(), users.end(), "*") != users.end()) - return true; - - if (find(users.begin(), users.end(), user) != users.end()) - return true; - - for (auto & i : users) - if (string(i, 0, 1) == "@") { - if (group == string(i, 1)) return true; - struct group * gr = getgrnam(i.c_str() + 1); - if (!gr) continue; - for (char * * mem = gr->gr_mem; *mem; mem++) - if (user == string(*mem)) return true; - } - - return false; -} - - -#define SD_LISTEN_FDS_START 3 - - -static void daemonLoop() -{ - if (chdir("/") == -1) - throw SysError("cannot change current directory"); - - /* Get rid of children automatically; don't let them become - zombies. */ - setSigChldAction(true); - - AutoCloseFD fdSocket; - - /* Handle socket-based activation by systemd. */ - if (getEnv("LISTEN_FDS") != "") { - if (getEnv("LISTEN_PID") != std::to_string(getpid()) || getEnv("LISTEN_FDS") != "1") - throw Error("unexpected systemd environment variables"); - fdSocket = SD_LISTEN_FDS_START; - } - - /* Otherwise, create and bind to a Unix domain socket. */ - else { - - /* Create and bind to a Unix domain socket. */ - fdSocket = socket(PF_UNIX, SOCK_STREAM, 0); - if (fdSocket == -1) - throw SysError("cannot create Unix domain socket"); - - string socketPath = settings.nixDaemonSocketFile; - - createDirs(dirOf(socketPath)); - - /* Urgh, sockaddr_un allows path names of only 108 characters. - So chdir to the socket directory so that we can pass a - relative path name. */ - if (chdir(dirOf(socketPath).c_str()) == -1) - throw SysError("cannot change current directory"); - Path socketPathRel = "./" + baseNameOf(socketPath); - - struct sockaddr_un addr; - addr.sun_family = AF_UNIX; - if (socketPathRel.size() >= sizeof(addr.sun_path)) - throw Error(format("socket path `%1%' is too long") % socketPathRel); - strcpy(addr.sun_path, socketPathRel.c_str()); - - unlink(socketPath.c_str()); - - /* Make sure that the socket is created with 0666 permission - (everybody can connect --- provided they have access to the - directory containing the socket). */ - mode_t oldMode = umask(0111); - int res = bind(fdSocket, (struct sockaddr *) &addr, sizeof(addr)); - umask(oldMode); - if (res == -1) - throw SysError(format("cannot bind to socket `%1%'") % socketPath); - - if (chdir("/") == -1) /* back to the root */ - throw SysError("cannot change current directory"); - - if (listen(fdSocket, 5) == -1) - throw SysError(format("cannot listen on socket `%1%'") % socketPath); - } - - closeOnExec(fdSocket); - - /* Loop accepting connections. */ - while (1) { - - try { - /* Important: the server process *cannot* open the SQLite - database, because it doesn't like forks very much. */ - assert(!store); - - /* Accept a connection. */ - struct sockaddr_un remoteAddr; - socklen_t remoteAddrLen = sizeof(remoteAddr); - - AutoCloseFD remote = accept(fdSocket, - (struct sockaddr *) &remoteAddr, &remoteAddrLen); - checkInterrupt(); - if (remote == -1) { - if (errno == EINTR) - continue; - else - throw SysError("accepting connection"); - } - - closeOnExec(remote); - - bool trusted = false; - pid_t clientPid = -1; + uid_t clientUid = (uid_t) -1; + gid_t clientGid = (gid_t) -1; + try { + /* Important: the server process *cannot* open the SQLite + database, because it doesn't like forks very much. */ + assert(!store); + + /* Accept a connection. */ + struct sockaddr_storage remoteAddr; + socklen_t remoteAddrLen = sizeof(remoteAddr); + + try_again: + AutoCloseFD remote = accept(fdSocket, + (struct sockaddr *) &remoteAddr, &remoteAddrLen); + checkInterrupt(); + if (remote == -1) { + if (errno == EINTR) + goto try_again; + else + throw SysError("accepting connection"); + } + + closeOnExec(remote); + + pid_t clientPid = -1; + bool trusted = false; + + /* Get the identity of the caller, if possible. */ + if (remoteAddr.ss_family == AF_UNIX) { #if defined(SO_PEERCRED) - /* Get the identity of the caller, if possible. */ - ucred cred; - socklen_t credLen = sizeof(cred); - if (getsockopt(remote, SOL_SOCKET, SO_PEERCRED, &cred, &credLen) == -1) - throw SysError("getting peer credentials"); + ucred cred; + socklen_t credLen = sizeof(cred); + if (getsockopt(remote, SOL_SOCKET, SO_PEERCRED, + &cred, &credLen) == -1) + throw SysError("getting peer credentials"); - clientPid = cred.pid; + clientPid = cred.pid; + clientUid = cred.uid; + clientGid = cred.gid; + trusted = clientUid == 0; struct passwd * pw = getpwuid(cred.uid); string user = pw ? pw->pw_name : std::to_string(cred.uid); - struct group * gr = getgrgid(cred.gid); - string group = gr ? gr->gr_name : std::to_string(cred.gid); - - Strings trustedUsers = settings.get("trusted-users", Strings({"root"})); - Strings allowedUsers = settings.get("allowed-users", Strings({"*"})); - - if (matchUser(user, group, trustedUsers)) - trusted = true; - - if (!trusted && !matchUser(user, group, allowedUsers)) - throw Error(format("user `%1%' is not allowed to connect to the Nix daemon") % user); - - printMsg(lvlInfo, format((string) "accepted connection from pid %1%, user %2%" - + (trusted ? " (trusted)" : "")) % clientPid % user); + printMsg(lvlInfo, + format((string) "accepted connection from pid %1%, user %2%") + % clientPid % user); #endif - - /* Fork a child to handle the connection. */ - startProcess([&]() { - fdSocket.close(); + } else { + char address_str[128]; + const char *result; + + if (remoteAddr.ss_family == AF_INET) { + struct sockaddr_in *addr = (struct sockaddr_in *) &remoteAddr; + struct in_addr inaddr = { addr->sin_addr }; + result = inet_ntop(AF_INET, &inaddr, + address_str, sizeof address_str); + } else if (remoteAddr.ss_family == AF_INET6) { + struct sockaddr_in6 *addr = (struct sockaddr_in6 *) &remoteAddr; + struct in6_addr inaddr = { addr->sin6_addr }; + result = inet_ntop(AF_INET6, &inaddr, + address_str, sizeof address_str); + } else { + result = NULL; + } + + if (result != NULL) { + printMsg(lvlInfo, + format("accepted connection from %1%") + % address_str); + } + } + + /* Fork a child to handle the connection. */ + startProcess([&]() { + close(fdSocket); /* Background the daemon. */ if (setsid() == -1) @@ -968,17 +905,11 @@ static void daemonLoop() strncpy(argvSaved[1], processName.c_str(), strlen(argvSaved[1])); } -#if defined(SO_PEERCRED) /* Store the client's user and group for this connection. This has to be done in the forked process since it is per - connection. */ - settings.clientUid = cred.uid; - settings.clientGid = cred.gid; -#else - /* Setting these to -1 means: do not change */ - settings.clientUid = (uid_t) -1; - settings.clientGid = (gid_t) -1; -#endif + connection. Setting these to -1 means: do not change. */ + settings.clientUid = clientUid; + settings.clientGid = clientGid; /* Handle the connection. */ from.fd = remote; @@ -988,23 +919,63 @@ static void daemonLoop() exit(0); }, false, "unexpected Nix daemon error: ", true); - } catch (Interrupted & e) { - throw; - } catch (Error & e) { - printMsg(lvlError, format("error processing connection: %1%") % e.msg()); - } + } catch (Interrupted & e) { + throw; + } catch (Error & e) { + printMsg(lvlError, format("error processing connection: %1%") % e.msg()); } } - -void run(Strings args) +static void daemonLoop(const std::vector<int>& sockets) { - for (Strings::iterator i = args.begin(); i != args.end(); ) { - string arg = *i++; - if (arg == "--daemon") /* ignored for backwards compatibility */; + if (chdir("/") == -1) + throw SysError("cannot change current directory"); + + /* Get rid of children automatically; don't let them become + zombies. */ + setSigChldAction(true); + + /* Mark sockets as close-on-exec. */ + for(int fd: sockets) { + closeOnExec(fd); } - daemonLoop(); + /* Prepare the FD set corresponding to SOCKETS. */ + auto initializeFDSet = [&](fd_set *set) { + FD_ZERO(set); + for (int fd: sockets) { + FD_SET(fd, set); + } + }; + + /* Loop accepting connections. */ + while (1) { + fd_set readfds; + + initializeFDSet(&readfds); + int count = + select(*std::max_element(sockets.begin(), sockets.end()) + 1, + &readfds, NULL, NULL, + NULL); + if (count < 0) { + int err = errno; + if (err == EINTR) + continue; + throw SysError(format("select error: %1%") % strerror(err)); + } + + for (unsigned int i = 0; i < sockets.size(); i++) { + if (FD_ISSET(sockets[i], &readfds)) { + acceptConnection(sockets[i]); + } + } + } +} + + +void run(const std::vector<int>& sockets) +{ + daemonLoop(sockets); } diff --git a/tests/guix-daemon.sh b/tests/guix-daemon.sh index 9186ffd585..7212e3eb68 100644 --- a/tests/guix-daemon.sh +++ b/tests/guix-daemon.sh @@ -81,6 +81,18 @@ guile -c " kill "$daemon_pid" +# Pass several '--listen' options, and make sure they are all honored. +guix-daemon --disable-chroot --listen="$socket" --listen="$socket-second" \ + --listen="localhost" --listen="localhost:9876" & +daemon_pid=$! + +for uri in "$socket" "$socket-second" \ + "guix://localhost" "guix://localhost:9876" +do + GUIX_DAEMON_SOCKET="$uri" guix build guile-bootstrap +done + +kill "$daemon_pid" # Check the failed build cache. |