/*** This file is part of systemd. Copyright 2010 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <errno.h> #include <fcntl.h> #include <inttypes.h> #include <limits.h> #include <poll.h> #include <signal.h> #include <stdbool.h> #include <stddef.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/inotify.h> #include <sys/signalfd.h> #include <sys/socket.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/uio.h> #include <sys/un.h> #include <termios.h> #include <unistd.h> #include "alloc-util.h" #include "ask-password-api.h" #include "fd-util.h" #include "fileio.h" #include "formats-util.h" #include "io-util.h" #include "log.h" #include "macro.h" #include "missing.h" #include "mkdir.h" #include "random-util.h" #include "signal-util.h" #include "socket-util.h" #include "string-util.h" #include "strv.h" #include "terminal-util.h" #include "time-util.h" #include "umask-util.h" #include "utf8.h" #include "util.h" #define KEYRING_TIMEOUT_USEC ((5 * USEC_PER_MINUTE) / 2) static int lookup_key(const char *keyname, key_serial_t *ret) { key_serial_t serial; assert(keyname); assert(ret); serial = request_key("user", keyname, NULL, 0); if (serial == -1) return negative_errno(); *ret = serial; return 0; } static int retrieve_key(key_serial_t serial, char ***ret) { _cleanup_free_ char *p = NULL; long m = 100, n; char **l; assert(ret); for (;;) { p = new(char, m); if (!p) return -ENOMEM; n = keyctl(KEYCTL_READ, (unsigned long) serial, (unsigned long) p, (unsigned long) m, 0); if (n < 0) return -errno; if (n < m) break; memory_erase(p, n); free(p); m *= 2; } l = strv_parse_nulstr(p, n); if (!l) return -ENOMEM; memory_erase(p, n); *ret = l; return 0; } static int add_to_keyring(const char *keyname, AskPasswordFlags flags, char **passwords) { _cleanup_strv_free_erase_ char **l = NULL; _cleanup_free_ char *p = NULL; key_serial_t serial; size_t n; int r; assert(keyname); assert(passwords); if (!(flags & ASK_PASSWORD_PUSH_CACHE)) return 0; r = lookup_key(keyname, &serial); if (r >= 0) { r = retrieve_key(serial, &l); if (r < 0) return r; } else if (r != -ENOKEY) return r; r = strv_extend_strv(&l, passwords, true); if (r <= 0) return r; r = strv_make_nulstr(l, &p, &n); if (r < 0) return r; /* Truncate trailing NUL */ assert(n > 0); assert(p[n-1] == 0); serial = add_key("user", keyname, p, n-1, KEY_SPEC_USER_KEYRING); memory_erase(p, n); if (serial == -1) return -errno; if (keyctl(KEYCTL_SET_TIMEOUT, (unsigned long) serial, (unsigned long) DIV_ROUND_UP(KEYRING_TIMEOUT_USEC, USEC_PER_SEC), 0, 0) < 0) log_debug_errno(errno, "Failed to adjust timeout: %m"); log_debug("Added key to keyring as %" PRIi32 ".", serial); return 1; } static int add_to_keyring_and_log(const char *keyname, AskPasswordFlags flags, char **passwords) { int r; assert(keyname); assert(passwords); r = add_to_keyring(keyname, flags, passwords); if (r < 0) return log_debug_errno(r, "Failed to add password to keyring: %m"); return 0; } int ask_password_keyring(const char *keyname, AskPasswordFlags flags, char ***ret) { key_serial_t serial; int r; assert(keyname); assert(ret); if (!(flags & ASK_PASSWORD_ACCEPT_CACHED)) return -EUNATCH; r = lookup_key(keyname, &serial); if (r == -ENOSYS) /* when retrieving the distinction doesn't matter */ return -ENOKEY; if (r < 0) return r; return retrieve_key(serial, ret); } static void backspace_chars(int ttyfd, size_t p) { if (ttyfd < 0) return; while (p > 0) { p--; loop_write(ttyfd, "\b \b", 3, false); } } int ask_password_tty( const char *message, const char *keyname, usec_t until, AskPasswordFlags flags, const char *flag_file, char **ret) { struct termios old_termios, new_termios; char passphrase[LINE_MAX + 1] = {}, *x; size_t p = 0, codepoint = 0; int r; _cleanup_close_ int ttyfd = -1, notify = -1; struct pollfd pollfd[2]; bool reset_tty = false; bool dirty = false; enum { POLL_TTY, POLL_INOTIFY }; assert(ret); if (flags & ASK_PASSWORD_NO_TTY) return -EUNATCH; if (!message) message = "Password:"; if (flag_file) { notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK); if (notify < 0) { r = -errno; goto finish; } if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0) { r = -errno; goto finish; } } ttyfd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC); if (ttyfd >= 0) { if (tcgetattr(ttyfd, &old_termios) < 0) { r = -errno; goto finish; } loop_write(ttyfd, ANSI_HIGHLIGHT, strlen(ANSI_HIGHLIGHT), false); loop_write(ttyfd, message, strlen(message), false); loop_write(ttyfd, " ", 1, false); loop_write(ttyfd, ANSI_NORMAL, strlen(ANSI_NORMAL), false); new_termios = old_termios; new_termios.c_lflag &= ~(ICANON|ECHO); new_termios.c_cc[VMIN] = 1; new_termios.c_cc[VTIME] = 0; if (tcsetattr(ttyfd, TCSADRAIN, &new_termios) < 0) { r = -errno; goto finish; } reset_tty = true; } zero(pollfd); pollfd[POLL_TTY].fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO; pollfd[POLL_TTY].events = POLLIN; pollfd[POLL_INOTIFY].fd = notify; pollfd[POLL_INOTIFY].events = POLLIN; for (;;) { char c; int sleep_for = -1, k; ssize_t n; if (until > 0) { usec_t y; y = now(CLOCK_MONOTONIC); if (y > until) { r = -ETIME; goto finish; } sleep_for = (int) ((until - y) / USEC_PER_MSEC); } if (flag_file) if (access(flag_file, F_OK) < 0) { r = -errno; goto finish; } k = poll(pollfd, notify >= 0 ? 2 : 1, sleep_for); if (k < 0) { if (errno == EINTR) continue; r = -errno; goto finish; } else if (k == 0) { r = -ETIME; goto finish; } if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0) flush_fd(notify); if (pollfd[POLL_TTY].revents == 0) continue; n = read(ttyfd >= 0 ? ttyfd : STDIN_FILENO, &c, 1); if (n < 0) { if (errno == EINTR || errno == EAGAIN) continue; r = -errno; goto finish; } else if (n == 0) break; if (c == '\n') break; else if (c == 21) { /* C-u */ if (!(flags & ASK_PASSWORD_SILENT)) backspace_chars(ttyfd, p); p = 0; } else if (c == '\b' || c == 127) { if (p > 0) { if (!(flags & ASK_PASSWORD_SILENT)) backspace_chars(ttyfd, 1); p--; } else if (!dirty && !(flags & ASK_PASSWORD_SILENT)) { flags |= ASK_PASSWORD_SILENT; /* There are two ways to enter silent * mode. Either by pressing backspace * as first key (and only as first * key), or ... */ if (ttyfd >= 0) loop_write(ttyfd, "(no echo) ", 10, false); } else if (ttyfd >= 0) loop_write(ttyfd, "\a", 1, false); } else if (c == '\t' && !(flags & ASK_PASSWORD_SILENT)) { backspace_chars(ttyfd, p); flags |= ASK_PASSWORD_SILENT; /* ... or by pressing TAB at any time. */ if (ttyfd >= 0) loop_write(ttyfd, "(no echo) ", 10, false); } else { if (p >= sizeof(passphrase)-1) { loop_write(ttyfd, "\a", 1, false); continue; } passphrase[p++] = c; if (!(flags & ASK_PASSWORD_SILENT) && ttyfd >= 0) { n = utf8_encoded_valid_unichar(passphrase + codepoint); if (n >= 0) { codepoint = p; loop_write(ttyfd, (flags & ASK_PASSWORD_ECHO) ? &c : "*", 1, false); } } dirty = true; } c = 'x'; } x = strndup(passphrase, p); memory_erase(passphrase, p); if (!x) { r = -ENOMEM; goto finish; } if (keyname) (void) add_to_keyring_and_log(keyname, flags, STRV_MAKE(x)); *ret = x; r = 0; finish: if (ttyfd >= 0 && reset_tty) { loop_write(ttyfd, "\n", 1, false); tcsetattr(ttyfd, TCSADRAIN, &old_termios); } return r; } static int create_socket(char **name) { union sockaddr_union sa = { .un.sun_family = AF_UNIX, }; _cleanup_close_ int fd = -1; static const int one = 1; char *c; int r; assert(name); fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (fd < 0) return -errno; snprintf(sa.un.sun_path, sizeof(sa.un.sun_path)-1, "/run/systemd/ask-password/sck.%" PRIx64, random_u64()); RUN_WITH_UMASK(0177) { if (bind(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path)) < 0) return -errno; } if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) < 0) return -errno; c = strdup(sa.un.sun_path); if (!c) return -ENOMEM; *name = c; r = fd; fd = -1; return r; } int ask_password_agent( const char *message, const char *icon, const char *id, const char *keyname, usec_t until, AskPasswordFlags flags, char ***ret) { enum { FD_SOCKET, FD_SIGNAL, _FD_MAX }; _cleanup_close_ int socket_fd = -1, signal_fd = -1, fd = -1; char temp[] = "/run/systemd/ask-password/tmp.XXXXXX"; char final[sizeof(temp)] = ""; _cleanup_free_ char *socket_name = NULL; _cleanup_strv_free_ char **l = NULL; _cleanup_fclose_ FILE *f = NULL; struct pollfd pollfd[_FD_MAX]; sigset_t mask, oldmask; int r; assert(ret); if (flags & ASK_PASSWORD_NO_AGENT) return -EUNATCH; assert_se(sigemptyset(&mask) >= 0); assert_se(sigset_add_many(&mask, SIGINT, SIGTERM, -1) >= 0); assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) >= 0); (void) mkdir_p_label("/run/systemd/ask-password", 0755); fd = mkostemp_safe(temp, O_WRONLY|O_CLOEXEC); if (fd < 0) { r = fd; goto finish; } (void) fchmod(fd, 0644); f = fdopen(fd, "w"); if (!f) { r = -errno; goto finish; } fd = -1; signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC); if (signal_fd < 0) { r = -errno; goto finish; } socket_fd = create_socket(&socket_name); if (socket_fd < 0) { r = socket_fd; goto finish; } fprintf(f, "[Ask]\n" "PID="PID_FMT"\n" "Socket=%s\n" "AcceptCached=%i\n" "Echo=%i\n" "NotAfter="USEC_FMT"\n", getpid(), socket_name, (flags & ASK_PASSWORD_ACCEPT_CACHED) ? 1 : 0, (flags & ASK_PASSWORD_ECHO) ? 1 : 0, until); if (message) fprintf(f, "Message=%s\n", message); if (icon) fprintf(f, "Icon=%s\n", icon); if (id) fprintf(f, "Id=%s\n", id); r = fflush_and_check(f); if (r < 0) goto finish; memcpy(final, temp, sizeof(temp)); final[sizeof(final)-11] = 'a'; final[sizeof(final)-10] = 's'; final[sizeof(final)-9] = 'k'; if (rename(temp, final) < 0) { r = -errno; goto finish; } zero(pollfd); pollfd[FD_SOCKET].fd = socket_fd; pollfd[FD_SOCKET].events = POLLIN; pollfd[FD_SIGNAL].fd = signal_fd; pollfd[FD_SIGNAL].events = POLLIN; for (;;) { char passphrase[LINE_MAX+1]; struct msghdr msghdr; struct iovec iovec; struct ucred *ucred; union { struct cmsghdr cmsghdr; uint8_t buf[CMSG_SPACE(sizeof(struct ucred))]; } control; ssize_t n; int k; usec_t t; t = now(CLOCK_MONOTONIC); if (until > 0 && until <= t) { r = -ETIME; goto finish; } k = poll(pollfd, _FD_MAX, until > 0 ? (int) ((until-t)/USEC_PER_MSEC) : -1); if (k < 0) { if (errno == EINTR) continue; r = -errno; goto finish; } if (k <= 0) { r = -ETIME; goto finish; } if (pollfd[FD_SIGNAL].revents & POLLIN) { r = -EINTR; goto finish; } if (pollfd[FD_SOCKET].revents != POLLIN) { r = -EIO; goto finish; } zero(iovec); iovec.iov_base = passphrase; iovec.iov_len = sizeof(passphrase); zero(control); zero(msghdr); msghdr.msg_iov = &iovec; msghdr.msg_iovlen = 1; msghdr.msg_control = &control; msghdr.msg_controllen = sizeof(control); n = recvmsg(socket_fd, &msghdr, 0); if (n < 0) { if (errno == EAGAIN || errno == EINTR) continue; r = -errno; goto finish; } cmsg_close_all(&msghdr); if (n <= 0) { log_debug("Message too short"); continue; } if (msghdr.msg_controllen < CMSG_LEN(sizeof(struct ucred)) || control.cmsghdr.cmsg_level != SOL_SOCKET || control.cmsghdr.cmsg_type != SCM_CREDENTIALS || control.cmsghdr.cmsg_len != CMSG_LEN(sizeof(struct ucred))) { log_debug("Received message without credentials. Ignoring."); continue; } ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr); if (ucred->uid != 0) { log_debug("Got request from unprivileged user. Ignoring."); continue; } if (passphrase[0] == '+') { /* An empty message refers to the empty password */ if (n == 1) l = strv_new("", NULL); else l = strv_parse_nulstr(passphrase+1, n-1); memory_erase(passphrase, n); if (!l) { r = -ENOMEM; goto finish; } if (strv_length(l) <= 0) { l = strv_free(l); log_debug("Invalid packet"); continue; } break; } if (passphrase[0] == '-') { r = -ECANCELED; goto finish; } log_debug("Invalid packet"); } if (keyname) (void) add_to_keyring_and_log(keyname, flags, l); *ret = l; l = NULL; r = 0; finish: if (socket_name) (void) unlink(socket_name); (void) unlink(temp); if (final[0]) (void) unlink(final); assert_se(sigprocmask(SIG_SETMASK, &oldmask, NULL) == 0); return r; } int ask_password_auto( const char *message, const char *icon, const char *id, const char *keyname, usec_t until, AskPasswordFlags flags, char ***ret) { int r; assert(ret); if ((flags & ASK_PASSWORD_ACCEPT_CACHED) && keyname) { r = ask_password_keyring(keyname, flags, ret); if (r != -ENOKEY) return r; } if (!(flags & ASK_PASSWORD_NO_TTY) && isatty(STDIN_FILENO)) { char *s = NULL, **l = NULL; r = ask_password_tty(message, keyname, until, flags, NULL, &s); if (r < 0) return r; r = strv_push(&l, s); if (r < 0) { string_erase(s); free(s); return -ENOMEM; } *ret = l; return 0; } if (!(flags & ASK_PASSWORD_NO_AGENT)) return ask_password_agent(message, icon, id, keyname, until, flags, ret); return -EUNATCH; }