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-rw-r--r--src/libsystemd-shared/src/ask-password-api.c734
1 files changed, 734 insertions, 0 deletions
diff --git a/src/libsystemd-shared/src/ask-password-api.c b/src/libsystemd-shared/src/ask-password-api.c
new file mode 100644
index 0000000000..b7f020b298
--- /dev/null
+++ b/src/libsystemd-shared/src/ask-password-api.c
@@ -0,0 +1,734 @@
+/***
+ 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 "systemd-basic/alloc-util.h"
+#include "systemd-basic/fd-util.h"
+#include "systemd-basic/fileio.h"
+#include "systemd-basic/formats-util.h"
+#include "systemd-basic/io-util.h"
+#include "systemd-basic/log.h"
+#include "systemd-basic/macro.h"
+#include "systemd-basic/missing.h"
+#include "systemd-basic/mkdir.h"
+#include "systemd-basic/random-util.h"
+#include "systemd-basic/signal-util.h"
+#include "systemd-basic/socket-util.h"
+#include "systemd-basic/string-util.h"
+#include "systemd-basic/strv.h"
+#include "systemd-basic/terminal-util.h"
+#include "systemd-basic/time-util.h"
+#include "systemd-basic/umask-util.h"
+#include "systemd-basic/utf8.h"
+#include "systemd-basic/util.h"
+#include "systemd-shared/ask-password-api.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;
+
+ serial = add_key("user", keyname, p, n, 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;
+ }
+
+ if (colors_enabled())
+ loop_write(ttyfd, ANSI_HIGHLIGHT, strlen(ANSI_HIGHLIGHT), false);
+ loop_write(ttyfd, message, strlen(message), false);
+ loop_write(ttyfd, " ", 1, false);
+ if (colors_enabled())
+ 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, SOCKADDR_UN_LEN(sa.un)) < 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);
+ 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;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-01 11:17:50 +0000