260672bd3f54ac0cf5bfc2032c7f5a51991c9f4aChad Kienle

#include <stdbool.h>

#include <termios.h>

#include <unistd.h>

#include <poll.h>

#include <sys/inotify.h>

#include <errno.h>

#include <fcntl.h>

#include <sys/socket.h>

#include <string.h>

#include <sys/un.h>

#include <stddef.h>

#include <sys/signalfd.h>

#include "util.h"

#include "formats-util.h"

#include "mkdir.h"

#include "strv.h"

#include "random-util.h"

#include "terminal-util.h"

#include "signal-util.h"

#include "ask-password-api.h"

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,

usec_t until,

bool echo,

const char *flag_file,

char **_passphrase) {

struct termios old_termios, new_termios;

char passphrase[LINE_MAX], *x;

size_t p = 0;

int r;

_cleanup_close_ int ttyfd = -1, notify = -1;

struct pollfd pollfd[2];

bool reset_tty = false;

bool silent_mode = false;

bool dirty = false;

enum {

POLL_TTY,

POLL_INOTIFY

};

assert(message);

assert(_passphrase);

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_ON, sizeof(ANSI_HIGHLIGHT_ON)-1, false);

loop_write(ttyfd, message, strlen(message), false);

loop_write(ttyfd, " ", 1, false);

loop_write(ttyfd, ANSI_HIGHLIGHT_OFF, sizeof(ANSI_HIGHLIGHT_OFF)-1, 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 (!silent_mode)

backspace_chars(ttyfd, p);

p = 0;

} else if (c == '\b' || c == 127) {

if (p > 0) {

if (!silent_mode)

backspace_chars(ttyfd, 1);

p--;

} else if (!dirty && !silent_mode) {

silent_mode = true;

/* There are two ways to enter silent

if (ttyfd >= 0)

loop_write(ttyfd, "(no echo) ", 10, false);

} else if (ttyfd >= 0)

loop_write(ttyfd, "\a", 1, false);

} else if (c == '\t' && !silent_mode) {

backspace_chars(ttyfd, p);

silent_mode = true;

/* ... 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 (!silent_mode && ttyfd >= 0)

loop_write(ttyfd, echo ? &c : "*", 1, false);

dirty = true;

}

}

x = strndup(passphrase, p);

if (!x) {

r = -ENOMEM;

goto finish;

}

*_passphrase = 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) {

int fd;

union {

struct sockaddr sa;

struct sockaddr_un un;

} sa = {

.un.sun_family = AF_UNIX,

};

int one = 1;

int r = 0;

char *c;

assert(name);

fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);

if (fd < 0)

return log_error_errno(errno, "socket() failed: %m");

snprintf(sa.un.sun_path, sizeof(sa.un.sun_path)-1, "/run/systemd/ask-password/sck.%" PRIx64, random_u64());

RUN_WITH_UMASK(0177) {

r = bind(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path));

}

if (r < 0) {

r = -errno;

log_error_errno(errno, "bind(%s) failed: %m", sa.un.sun_path);

goto fail;

}

if (setsockopt(fd, SOL_SOCKET, SO_PASSCRED, &one, sizeof(one)) < 0) {

r = -errno;

log_error_errno(errno, "SO_PASSCRED failed: %m");

goto fail;

}

c = strdup(sa.un.sun_path);

if (!c) {

r = log_oom();

goto fail;

}

*name = c;

return fd;

fail:

safe_close(fd);

return r;

}

int ask_password_agent(

const char *message,

const char *icon,

const char *id,

usec_t until,

bool echo,

bool accept_cached,

char ***_passphrases) {

enum {

FD_SOCKET,

FD_SIGNAL,

_FD_MAX

};

char temp[] = "/run/systemd/ask-password/tmp.XXXXXX";

char final[sizeof(temp)] = "";

_cleanup_fclose_ FILE *f = NULL;

_cleanup_free_ char *socket_name = NULL;

_cleanup_close_ int socket_fd = -1, signal_fd = -1, fd = -1;

sigset_t mask, oldmask;

struct pollfd pollfd[_FD_MAX];

int r;

assert(_passphrases);

assert_se(sigemptyset(&mask) == 0);

sigset_add_many(&mask, SIGINT, SIGTERM, -1);

assert_se(sigprocmask(SIG_BLOCK, &mask, &oldmask) == 0);

mkdir_p_label("/run/systemd/ask-password", 0755);

fd = mkostemp_safe(temp, O_WRONLY|O_CLOEXEC);

if (fd < 0) {

log_error_errno(errno, "Failed to create password file: %m");

r = -errno;

goto finish;

}

fchmod(fd, 0644);

f = fdopen(fd, "w");

if (!f) {

log_error_errno(errno, "Failed to allocate FILE: %m");

r = -errno;

goto finish;

}

fd = -1;

signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);

if (signal_fd < 0) {

log_error_errno(errno, "signalfd(): %m");

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,

accept_cached ? 1 : 0,

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);

fflush(f);

if (ferror(f)) {

log_error_errno(errno, "Failed to write query file: %m");

r = -errno;

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) {

log_error_errno(errno, "Failed to rename query file: %m");

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) {

log_notice("Timed out");

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;

log_error_errno(errno, "poll() failed: %m");

r = -errno;

goto finish;

}

if (k <= 0) {

log_notice("Timed out");

r = -ETIME;

goto finish;

}

if (pollfd[FD_SIGNAL].revents & POLLIN) {

r = -EINTR;

goto finish;

}

if (pollfd[FD_SOCKET].revents != POLLIN) {

log_error("Unexpected poll() event.");

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;

log_error_errno(errno, "recvmsg() failed: %m");

r = -errno;

goto finish;

}

cmsg_close_all(&msghdr);

if (n <= 0) {

log_error("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_warning("Received message without credentials. Ignoring.");

continue;

}

ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);

if (ucred->uid != 0) {

log_warning("Got request from unprivileged user. Ignoring.");

continue;

}

if (passphrase[0] == '+') {

char **l;

if (n == 1)

l = strv_new("", NULL);

else

l = strv_parse_nulstr(passphrase+1, n-1);

/* An empty message refers to the empty password */

if (!l) {

r = -ENOMEM;

goto finish;

}

if (strv_length(l) <= 0) {

strv_free(l);

log_error("Invalid packet");

continue;

}

*_passphrases = l;

} else if (passphrase[0] == '-') {

r = -ECANCELED;

goto finish;

} else {

log_error("Invalid packet");

continue;

}

break;

}

r = 0;

finish:

if (socket_name)

unlink(socket_name);

unlink(temp);

if (final[0])

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,

usec_t until, bool accept_cached, char ***_passphrases) {

assert(message);

assert(_passphrases);

if (isatty(STDIN_FILENO)) {

int r;

char *s = NULL, **l = NULL;

r = ask_password_tty(message, until, false, NULL, &s);

if (r < 0)

return r;

r = strv_consume(&l, s);

if (r < 0)

return r;

*_passphrases = l;

return r;

} else

return ask_password_agent(message, icon, id, until, false, accept_cached, _passphrases);

}