Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1002 insertions, 0 deletions

diff --git a/src/shared/ask-password-api.c b/src/shared/ask-password-api.c
new file mode 100644
index 0000000..0e323f4
--- /dev/null
+++ b/src/shared/ask-password-api.c
@@ -0,0 +1,1002 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/inotify.h>
+#include <sys/signalfd.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 "creds-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "format-util.h"
+#include "fs-util.h"
+#include "glyph-util.h"
+#include "io-util.h"
+#include "iovec-util.h"
+#include "keyring-util.h"
+#include "log.h"
+#include "macro.h"
+#include "memory-util.h"
+#include "missing_syscall.h"
+#include "mkdir-label.h"
+#include "nulstr-util.h"
+#include "plymouth-util.h"
+#include "process-util.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 "tmpfile-util.h"
+#include "umask-util.h"
+#include "utf8.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_(erase_and_freep) void *p = NULL;
+        char **l;
+        size_t n;
+        int r;
+
+        assert(ret);
+
+        r = keyring_read(serial, &p, &n);
+        if (r < 0)
+                return r;
+
+        l = strv_parse_nulstr(p, n);
+        if (!l)
+                return -ENOMEM;
+
+        *ret = l;
+        return 0;
+}
+
+static int add_to_keyring(const char *keyname, AskPasswordFlags flags, char **passwords) {
+        _cleanup_strv_free_erase_ char **l = NULL;
+        _cleanup_(erase_and_freep) char *p = NULL;
+        key_serial_t serial;
+        size_t n;
+        int r;
+
+        assert(keyname);
+
+        if (!FLAGS_SET(flags, ASK_PASSWORD_PUSH_CACHE))
+                return 0;
+        if (strv_isempty(passwords))
+                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;
+
+        /* chop off the final NUL byte. We do this because we want to use the separator NUL bytes only if we
+         * have multiple passwords. */
+        n = LESS_BY(n, (size_t) 1);
+
+        serial = add_key("user", keyname, p, n, KEY_SPEC_USER_KEYRING);
+        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 kernel keyring key timeout: %m");
+
+        /* Tell everyone to check the keyring */
+        (void) touch("/run/systemd/ask-password");
+
+        log_debug("Added key to kernel keyring as %" PRIi32 ".", serial);
+
+        return 1;
+}
+
+static int add_to_keyring_and_log(const char *keyname, AskPasswordFlags flags, char **passwords) {
+        int r;
+
+        assert(keyname);
+
+        r = add_to_keyring(keyname, flags, passwords);
+        if (r < 0)
+                return log_debug_errno(r, "Failed to add password to kernel keyring: %m");
+
+        return 0;
+}
+
+static int ask_password_keyring(const char *keyname, AskPasswordFlags flags, char ***ret) {
+
+        key_serial_t serial;
+        int r;
+
+        assert(keyname);
+        assert(ret);
+
+        if (!FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED))
+                return -EUNATCH;
+
+        r = lookup_key(keyname, &serial);
+        if (ERRNO_IS_NEG_NOT_SUPPORTED(r) || r == -EPERM)
+                /* When retrieving, the distinction between "kernel or container manager don't support or
+                 * allow this" and "no matching key known" doesn't matter. Note that we propagate EACCESS
+                 * here (even if EPERM not) since that is used if the keyring is available, but we lack
+                 * access to the key. */
+                return -ENOKEY;
+        if (r < 0)
+                return r;
+
+        return retrieve_key(serial, ret);
+}
+
+static int backspace_chars(int ttyfd, size_t p) {
+        if (ttyfd < 0)
+                return 0;
+
+        _cleanup_free_ char *buf = malloc_multiply(3, p);
+        if (!buf)
+                return log_oom();
+
+        for (size_t i = 0; i < p; i++)
+                memcpy(buf + 3 * i, "\b \b", 3);
+
+        return loop_write(ttyfd, buf, 3 * p);
+}
+
+static int backspace_string(int ttyfd, const char *str) {
+        assert(str);
+
+        /* Backspaces through enough characters to entirely undo printing of the specified string. */
+
+        if (ttyfd < 0)
+                return 0;
+
+        size_t m = utf8_n_codepoints(str);
+        if (m == SIZE_MAX)
+                m = strlen(str); /* Not a valid UTF-8 string? If so, let's backspace the number of bytes
+                                  * output. Most likely this happened because we are not in a UTF-8 locale,
+                                  * and in that case that is the correct thing to do. And even if it's not,
+                                  * terminals tend to stop backspacing at the leftmost column, hence
+                                  * backspacing too much should be mostly OK. */
+
+        return backspace_chars(ttyfd, m);
+}
+
+int ask_password_plymouth(
+                const char *message,
+                usec_t until,
+                AskPasswordFlags flags,
+                const char *flag_file,
+                char ***ret) {
+
+        _cleanup_close_ int fd = -EBADF, notify = -EBADF;
+        _cleanup_free_ char *packet = NULL;
+        ssize_t k;
+        int r, n;
+        struct pollfd pollfd[2] = {};
+        char buffer[LINE_MAX];
+        size_t p = 0;
+        enum {
+                POLL_SOCKET,
+                POLL_INOTIFY
+        };
+
+        assert(ret);
+
+        if (!message)
+                message = "Password:";
+
+        if (flag_file) {
+                notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
+                if (notify < 0)
+                        return -errno;
+
+                if (inotify_add_watch(notify, flag_file, IN_ATTRIB) < 0) /* for the link count */
+                        return -errno;
+        }
+
+        fd = plymouth_connect(SOCK_NONBLOCK);
+        if (fd < 0)
+                return fd;
+
+        if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED)) {
+                packet = strdup("c");
+                n = 1;
+        } else if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0)
+                packet = NULL;
+        if (!packet)
+                return -ENOMEM;
+
+        r = loop_write_full(fd, packet, n + 1, USEC_INFINITY);
+        if (r < 0)
+                return r;
+
+        CLEANUP_ERASE(buffer);
+
+        pollfd[POLL_SOCKET].fd = fd;
+        pollfd[POLL_SOCKET].events = POLLIN;
+        pollfd[POLL_INOTIFY].fd = notify;
+        pollfd[POLL_INOTIFY].events = POLLIN;
+
+        for (;;) {
+                usec_t timeout;
+
+                if (until > 0)
+                        timeout = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
+                else
+                        timeout = USEC_INFINITY;
+
+                if (flag_file && access(flag_file, F_OK) < 0)
+                        return -errno;
+
+                r = ppoll_usec(pollfd, notify >= 0 ? 2 : 1, timeout);
+                if (r == -EINTR)
+                        continue;
+                if (r < 0)
+                        return r;
+                if (r == 0)
+                        return -ETIME;
+
+                if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0)
+                        (void) flush_fd(notify);
+
+                if (pollfd[POLL_SOCKET].revents == 0)
+                        continue;
+
+                k = read(fd, buffer + p, sizeof(buffer) - p);
+                if (k < 0) {
+                        if (ERRNO_IS_TRANSIENT(errno))
+                                continue;
+
+                        return -errno;
+                }
+                if (k == 0)
+                        return -EIO;
+
+                p += k;
+
+                if (buffer[0] == 5) {
+
+                        if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED)) {
+                                /* Hmm, first try with cached
+                                 * passwords failed, so let's retry
+                                 * with a normal password request */
+                                packet = mfree(packet);
+
+                                if (asprintf(&packet, "*\002%c%s%n", (int) (strlen(message) + 1), message, &n) < 0)
+                                        return -ENOMEM;
+
+                                r = loop_write_full(fd, packet, n + 1, USEC_INFINITY);
+                                if (r < 0)
+                                        return r;
+
+                                flags &= ~ASK_PASSWORD_ACCEPT_CACHED;
+                                p = 0;
+                                continue;
+                        }
+
+                        /* No password, because UI not shown */
+                        return -ENOENT;
+
+                } else if (IN_SET(buffer[0], 2, 9)) {
+                        uint32_t size;
+                        char **l;
+
+                        /* One or more answers */
+                        if (p < 5)
+                                continue;
+
+                        memcpy(&size, buffer+1, sizeof(size));
+                        size = le32toh(size);
+                        if (size + 5 > sizeof(buffer))
+                                return -EIO;
+
+                        if (p-5 < size)
+                                continue;
+
+                        l = strv_parse_nulstr(buffer + 5, size);
+                        if (!l)
+                                return -ENOMEM;
+
+                        *ret = l;
+                        break;
+
+                } else
+                        /* Unknown packet */
+                        return -EIO;
+        }
+
+        return 0;
+}
+
+#define NO_ECHO "(no echo) "
+#define PRESS_TAB "(press TAB for no echo) "
+#define SKIPPED "(skipped)"
+
+int ask_password_tty(
+                int ttyfd,
+                const char *message,
+                const char *keyname,
+                usec_t until,
+                AskPasswordFlags flags,
+                const char *flag_file,
+                char ***ret) {
+
+        enum {
+                POLL_TTY,
+                POLL_INOTIFY,
+                _POLL_MAX,
+        };
+
+        bool reset_tty = false, dirty = false, use_color = false, press_tab_visible = false;
+        _cleanup_close_ int cttyfd = -EBADF, notify = -EBADF;
+        struct termios old_termios, new_termios;
+        char passphrase[LINE_MAX + 1] = {}, *x;
+        _cleanup_strv_free_erase_ char **l = NULL;
+        struct pollfd pollfd[_POLL_MAX];
+        size_t p = 0, codepoint = 0;
+        int r;
+
+        assert(ret);
+
+        if (FLAGS_SET(flags, ASK_PASSWORD_NO_TTY))
+                return -EUNATCH;
+
+        if (!message)
+                message = "Password:";
+
+        if (!FLAGS_SET(flags, ASK_PASSWORD_HIDE_EMOJI) && emoji_enabled())
+                message = strjoina(special_glyph(SPECIAL_GLYPH_LOCK_AND_KEY), " ", message);
+
+        if (flag_file || (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) && keyname)) {
+                notify = inotify_init1(IN_CLOEXEC|IN_NONBLOCK);
+                if (notify < 0)
+                        return -errno;
+        }
+        if (flag_file) {
+                if (inotify_add_watch(notify, flag_file, IN_ATTRIB /* for the link count */) < 0)
+                        return -errno;
+        }
+        if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
+                r = ask_password_keyring(keyname, flags, ret);
+                if (r >= 0)
+                        return 0;
+                else if (r != -ENOKEY)
+                        return r;
+
+                if (inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */) < 0)
+                        return -errno;
+        }
+
+        CLEANUP_ERASE(passphrase);
+
+        /* If the caller didn't specify a TTY, then use the controlling tty, if we can. */
+        if (ttyfd < 0)
+                ttyfd = cttyfd = open("/dev/tty", O_RDWR|O_NOCTTY|O_CLOEXEC);
+
+        if (ttyfd >= 0) {
+                if (tcgetattr(ttyfd, &old_termios) < 0)
+                        return -errno;
+
+                if (FLAGS_SET(flags, ASK_PASSWORD_CONSOLE_COLOR))
+                        use_color = dev_console_colors_enabled();
+                else
+                        use_color = colors_enabled();
+
+                if (use_color)
+                        (void) loop_write(ttyfd, ANSI_HIGHLIGHT, SIZE_MAX);
+
+                (void) loop_write(ttyfd, message, SIZE_MAX);
+                (void) loop_write(ttyfd, " ", 1);
+
+                if (!FLAGS_SET(flags, ASK_PASSWORD_SILENT) && !FLAGS_SET(flags, ASK_PASSWORD_ECHO)) {
+                        if (use_color)
+                                (void) loop_write(ttyfd, ansi_grey(), SIZE_MAX);
+
+                        (void) loop_write(ttyfd, PRESS_TAB, SIZE_MAX);
+                        press_tab_visible = true;
+                }
+
+                if (use_color)
+                        (void) loop_write(ttyfd, ANSI_NORMAL, SIZE_MAX);
+
+                new_termios = old_termios;
+                new_termios.c_lflag &= ~(ICANON|ECHO);
+                new_termios.c_cc[VMIN] = 1;
+                new_termios.c_cc[VTIME] = 0;
+
+                r = RET_NERRNO(tcsetattr(ttyfd, TCSADRAIN, &new_termios));
+                if (r < 0)
+                        goto finish;
+
+                reset_tty = true;
+        }
+
+        pollfd[POLL_TTY] = (struct pollfd) {
+                .fd = ttyfd >= 0 ? ttyfd : STDIN_FILENO,
+                .events = POLLIN,
+        };
+        pollfd[POLL_INOTIFY] = (struct pollfd) {
+                .fd = notify,
+                .events = POLLIN,
+        };
+
+        for (;;) {
+                _cleanup_(erase_char) char c;
+                usec_t timeout;
+                ssize_t n;
+
+                if (until > 0)
+                        timeout = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
+                else
+                        timeout = USEC_INFINITY;
+
+                if (flag_file) {
+                        r = RET_NERRNO(access(flag_file, F_OK));
+                        if (r < 0)
+                                goto finish;
+                }
+
+                r = ppoll_usec(pollfd, notify >= 0 ? 2 : 1, timeout);
+                if (r == -EINTR)
+                        continue;
+                if (r < 0)
+                        goto finish;
+                if (r == 0) {
+                        r = -ETIME;
+                        goto finish;
+                }
+
+                if (notify >= 0 && pollfd[POLL_INOTIFY].revents != 0 && keyname) {
+                        (void) flush_fd(notify);
+
+                        r = ask_password_keyring(keyname, flags, ret);
+                        if (r >= 0) {
+                                r = 0;
+                                goto finish;
+                        } else if (r != -ENOKEY)
+                                goto finish;
+                }
+
+                if (pollfd[POLL_TTY].revents == 0)
+                        continue;
+
+                n = read(ttyfd >= 0 ? ttyfd : STDIN_FILENO, &c, 1);
+                if (n < 0) {
+                        if (ERRNO_IS_TRANSIENT(errno))
+                                continue;
+
+                        r = -errno;
+                        goto finish;
+
+                }
+
+                if (press_tab_visible) {
+                        assert(ttyfd >= 0);
+                        backspace_chars(ttyfd, strlen(PRESS_TAB));
+                        press_tab_visible = false;
+                }
+
+                /* We treat EOF, newline and NUL byte all as valid end markers */
+                if (n == 0 || c == '\n' || c == 0)
+                        break;
+
+                if (c == 4) { /* C-d also known as EOT */
+                        if (ttyfd >= 0)
+                                (void) loop_write(ttyfd, SKIPPED, SIZE_MAX);
+
+                        goto skipped;
+                }
+
+                if (c == 21) { /* C-u */
+
+                        if (!FLAGS_SET(flags, ASK_PASSWORD_SILENT))
+                                (void) backspace_string(ttyfd, passphrase);
+
+                        explicit_bzero_safe(passphrase, sizeof(passphrase));
+                        p = codepoint = 0;
+
+                } else if (IN_SET(c, '\b', 127)) {
+
+                        if (p > 0) {
+                                size_t q;
+
+                                if (!FLAGS_SET(flags, ASK_PASSWORD_SILENT))
+                                        (void) backspace_chars(ttyfd, 1);
+
+                                /* Remove a full UTF-8 codepoint from the end. For that, figure out where the
+                                 * last one begins */
+                                q = 0;
+                                for (;;) {
+                                        int z;
+
+                                        z = utf8_encoded_valid_unichar(passphrase + q, SIZE_MAX);
+                                        if (z <= 0) {
+                                                q = SIZE_MAX; /* Invalid UTF8! */
+                                                break;
+                                        }
+
+                                        if (q + z >= p) /* This one brings us over the edge */
+                                                break;
+
+                                        q += z;
+                                }
+
+                                p = codepoint = q == SIZE_MAX ? p - 1 : q;
+                                explicit_bzero_safe(passphrase + p, sizeof(passphrase) - p);
+
+                        } else if (!dirty && !FLAGS_SET(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)
+                                        (void) loop_write(ttyfd, NO_ECHO, SIZE_MAX);
+
+                        } else if (ttyfd >= 0)
+                                (void) loop_write(ttyfd, "\a", 1);
+
+                } else if (c == '\t' && !FLAGS_SET(flags, ASK_PASSWORD_SILENT)) {
+
+                        (void) backspace_string(ttyfd, passphrase);
+                        flags |= ASK_PASSWORD_SILENT;
+
+                        /* ... or by pressing TAB at any time. */
+
+                        if (ttyfd >= 0)
+                                (void) loop_write(ttyfd, NO_ECHO, SIZE_MAX);
+
+                } else if (p >= sizeof(passphrase)-1) {
+
+                        /* Reached the size limit */
+                        if (ttyfd >= 0)
+                                (void) loop_write(ttyfd, "\a", 1);
+
+                } else {
+                        passphrase[p++] = c;
+
+                        if (!FLAGS_SET(flags, ASK_PASSWORD_SILENT) && ttyfd >= 0) {
+                                /* Check if we got a complete UTF-8 character now. If so, let's output one '*'. */
+                                n = utf8_encoded_valid_unichar(passphrase + codepoint, SIZE_MAX);
+                                if (n >= 0) {
+                                        if (FLAGS_SET(flags, ASK_PASSWORD_ECHO))
+                                                (void) loop_write(ttyfd, passphrase + codepoint, n);
+                                        else
+                                                (void) loop_write(ttyfd,
+                                                                  special_glyph(SPECIAL_GLYPH_BULLET),
+                                                                  SIZE_MAX);
+                                        codepoint = p;
+                                }
+                        }
+
+                        dirty = true;
+                }
+        }
+
+        x = strndup(passphrase, p);
+        if (!x) {
+                r = -ENOMEM;
+                goto finish;
+        }
+
+        r = strv_consume(&l, x);
+        if (r < 0)
+                goto finish;
+
+skipped:
+        if (strv_isempty(l))
+                r = log_debug_errno(SYNTHETIC_ERRNO(ECANCELED), "Password query was cancelled.");
+        else {
+                if (keyname)
+                        (void) add_to_keyring_and_log(keyname, flags, l);
+
+                *ret = TAKE_PTR(l);
+                r = 0;
+        }
+
+finish:
+        if (ttyfd >= 0 && reset_tty) {
+                (void) loop_write(ttyfd, "\n", 1);
+                (void) tcsetattr(ttyfd, TCSADRAIN, &old_termios);
+        }
+
+        return r;
+}
+
+static int create_socket(char **ret) {
+        _cleanup_free_ char *path = NULL;
+        union sockaddr_union sa;
+        socklen_t sa_len;
+        _cleanup_close_ int fd = -EBADF;
+        int r;
+
+        assert(ret);
+
+        fd = socket(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0);
+        if (fd < 0)
+                return -errno;
+
+        if (asprintf(&path, "/run/systemd/ask-password/sck.%" PRIx64, random_u64()) < 0)
+                return -ENOMEM;
+
+        r = sockaddr_un_set_path(&sa.un, path);
+        if (r < 0)
+                return r;
+        sa_len = r;
+
+        WITH_UMASK(0177)
+                if (bind(fd, &sa.sa, sa_len) < 0)
+                        return -errno;
+
+        r = setsockopt_int(fd, SOL_SOCKET, SO_PASSCRED, true);
+        if (r < 0)
+                return r;
+
+        *ret = TAKE_PTR(path);
+        return TAKE_FD(fd);
+}
+
+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_INOTIFY,
+                _FD_MAX
+        };
+
+        _cleanup_close_ int socket_fd = -EBADF, signal_fd = -EBADF, notify = -EBADF, fd = -EBADF;
+        char temp[] = "/run/systemd/ask-password/tmp.XXXXXX";
+        char final[sizeof(temp)] = "";
+        _cleanup_free_ char *socket_name = NULL;
+        _cleanup_strv_free_erase_ char **l = NULL;
+        _cleanup_fclose_ FILE *f = NULL;
+        struct pollfd pollfd[_FD_MAX];
+        sigset_t mask, oldmask;
+        int r;
+
+        assert(ret);
+
+        if (FLAGS_SET(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);
+
+        if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) && keyname) {
+                r = ask_password_keyring(keyname, flags, ret);
+                if (r >= 0) {
+                        r = 0;
+                        goto finish;
+                } else if (r != -ENOKEY)
+                        goto finish;
+
+                notify = inotify_init1(IN_CLOEXEC | IN_NONBLOCK);
+                if (notify < 0) {
+                        r = -errno;
+                        goto finish;
+                }
+
+                r = RET_NERRNO(inotify_add_watch(notify, "/run/systemd/ask-password", IN_ATTRIB /* for mtime */));
+                if (r < 0)
+                        goto finish;
+        }
+
+        fd = mkostemp_safe(temp);
+        if (fd < 0) {
+                r = fd;
+                goto finish;
+        }
+
+        (void) fchmod(fd, 0644);
+
+        f = take_fdopen(&fd, "w");
+        if (!f) {
+                r = -errno;
+                goto finish;
+        }
+
+        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"
+                "Silent=%i\n",
+                getpid_cached(),
+                socket_name,
+                FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED),
+                FLAGS_SET(flags, ASK_PASSWORD_ECHO),
+                until,
+                FLAGS_SET(flags, ASK_PASSWORD_SILENT));
+
+        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';
+
+        r = RET_NERRNO(rename(temp, final));
+        if (r < 0)
+                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;
+        pollfd[FD_INOTIFY].fd = notify;
+        pollfd[FD_INOTIFY].events = POLLIN;
+
+        for (;;) {
+                CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control;
+                char passphrase[LINE_MAX+1];
+                struct iovec iovec;
+                struct ucred *ucred;
+                usec_t timeout;
+                ssize_t n;
+
+                if (until > 0)
+                        timeout = usec_sub_unsigned(until, now(CLOCK_MONOTONIC));
+                else
+                        timeout = USEC_INFINITY;
+
+                r = ppoll_usec(pollfd, notify >= 0 ? _FD_MAX : _FD_MAX - 1, timeout);
+                if (r == -EINTR)
+                        continue;
+                if (r < 0)
+                        goto finish;
+                if (r == 0) {
+                        r = -ETIME;
+                        goto finish;
+                }
+
+                if (pollfd[FD_SIGNAL].revents & POLLIN) {
+                        r = -EINTR;
+                        goto finish;
+                }
+
+                if (notify >= 0 && pollfd[FD_INOTIFY].revents != 0) {
+                        (void) flush_fd(notify);
+
+                        r = ask_password_keyring(keyname, flags, ret);
+                        if (r >= 0) {
+                                r = 0;
+                                goto finish;
+                        } else if (r != -ENOKEY)
+                                goto finish;
+                }
+
+                if (pollfd[FD_SOCKET].revents == 0)
+                        continue;
+
+                if (pollfd[FD_SOCKET].revents != POLLIN) {
+                        r = -EIO;
+                        goto finish;
+                }
+
+                iovec = IOVEC_MAKE(passphrase, sizeof(passphrase));
+
+                struct msghdr msghdr = {
+                        .msg_iov = &iovec,
+                        .msg_iovlen = 1,
+                        .msg_control = &control,
+                        .msg_controllen = sizeof(control),
+                };
+
+                n = recvmsg_safe(socket_fd, &msghdr, 0);
+                if (ERRNO_IS_NEG_TRANSIENT(n))
+                        continue;
+                else if (n == -EXFULL) {
+                        log_debug("Got message with truncated control data, ignoring.");
+                        continue;
+                } else if (n < 0) {
+                        r = (int) n;
+                        goto finish;
+                }
+
+                CLEANUP_ERASE(passphrase);
+
+                cmsg_close_all(&msghdr);
+
+                if (n == 0) {
+                        log_debug("Message too short");
+                        continue;
+                }
+
+                ucred = CMSG_FIND_DATA(&msghdr, SOL_SOCKET, SCM_CREDENTIALS, struct ucred);
+                if (!ucred) {
+                        log_debug("Received message without credentials. Ignoring.");
+                        continue;
+                }
+
+                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("");
+                        else
+                                l = strv_parse_nulstr(passphrase+1, n-1);
+                        if (!l) {
+                                r = -ENOMEM;
+                                goto finish;
+                        }
+
+                        if (strv_isempty(l)) {
+                                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 = TAKE_PTR(l);
+        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;
+}
+
+static int ask_password_credential(const char *credential_name, AskPasswordFlags flags, char ***ret) {
+        _cleanup_(erase_and_freep) char *buffer = NULL;
+        size_t size;
+        char **l;
+        int r;
+
+        assert(credential_name);
+        assert(ret);
+
+        r = read_credential(credential_name, (void**) &buffer, &size);
+        if (IN_SET(r, -ENXIO, -ENOENT)) /* No credentials passed or this credential not defined? */
+                return -ENOKEY;
+
+        l = strv_parse_nulstr(buffer, size);
+        if (!l)
+                return -ENOMEM;
+
+        *ret = l;
+        return 0;
+}
+
+int ask_password_auto(
+                const char *message,
+                const char *icon,
+                const char *id,                /* id in "ask-password" protocol */
+                const char *key_name,          /* name in kernel keyring */
+                const char *credential_name,   /* name in $CREDENTIALS_DIRECTORY directory */
+                usec_t until,
+                AskPasswordFlags flags,
+                char ***ret) {
+
+        int r;
+
+        assert(ret);
+
+        if (!FLAGS_SET(flags, ASK_PASSWORD_NO_CREDENTIAL) && credential_name) {
+                r = ask_password_credential(credential_name, flags, ret);
+                if (r != -ENOKEY)
+                        return r;
+        }
+
+        if (FLAGS_SET(flags, ASK_PASSWORD_ACCEPT_CACHED) &&
+            key_name &&
+            (FLAGS_SET(flags, ASK_PASSWORD_NO_TTY) || !isatty(STDIN_FILENO)) &&
+            FLAGS_SET(flags, ASK_PASSWORD_NO_AGENT)) {
+                r = ask_password_keyring(key_name, flags, ret);
+                if (r != -ENOKEY)
+                        return r;
+        }
+
+        if (!FLAGS_SET(flags, ASK_PASSWORD_NO_TTY) && isatty(STDIN_FILENO))
+                return ask_password_tty(-1, message, key_name, until, flags, NULL, ret);
+
+        if (!FLAGS_SET(flags, ASK_PASSWORD_NO_AGENT))
+                return ask_password_agent(message, icon, id, key_name, until, flags, ret);
+
+        return -EUNATCH;
+}