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systemd/src/core/execute.c
Zbigniew Jędrzejewski-Szmek 4014818d53 Merge pull request #4806 from poettering/keyring-init 
set up a per-service session kernel keyring, and store the invocation ID in it
2016-12-13 23:24:42 -05:00

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/***
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 <glob.h>
#include <grp.h>
#include <poll.h>
#include <signal.h>
#include <string.h>
#include <sys/capability.h>
#include <sys/eventfd.h>
#include <sys/mman.h>
#include <sys/personality.h>
#include <sys/prctl.h>
#include <sys/shm.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/un.h>
#include <unistd.h>
#include <utmpx.h>
#ifdef HAVE_PAM
#include <security/pam_appl.h>
#endif
#ifdef HAVE_SELINUX
#include <selinux/selinux.h>
#endif
#ifdef HAVE_SECCOMP
#include <seccomp.h>
#endif
#ifdef HAVE_APPARMOR
#include <sys/apparmor.h>
#endif
#include "sd-messages.h"
#include "af-list.h"
#include "alloc-util.h"
#ifdef HAVE_APPARMOR
#include "apparmor-util.h"
#endif
#include "async.h"
#include "barrier.h"
#include "cap-list.h"
#include "capability-util.h"
#include "def.h"
#include "env-util.h"
#include "errno-list.h"
#include "execute.h"
#include "exit-status.h"
#include "fd-util.h"
#include "fileio.h"
#include "format-util.h"
#include "fs-util.h"
#include "glob-util.h"
#include "io-util.h"
#include "ioprio.h"
#include "log.h"
#include "macro.h"
#include "missing.h"
#include "mkdir.h"
#include "namespace.h"
#include "parse-util.h"
#include "path-util.h"
#include "process-util.h"
#include "rlimit-util.h"
#include "rm-rf.h"
#ifdef HAVE_SECCOMP
#include "seccomp-util.h"
#endif
#include "securebits.h"
#include "selinux-util.h"
#include "signal-util.h"
#include "smack-util.h"
#include "special.h"
#include "string-table.h"
#include "string-util.h"
#include "strv.h"
#include "syslog-util.h"
#include "terminal-util.h"
#include "unit.h"
#include "user-util.h"
#include "util.h"
#include "utmp-wtmp.h"
#define IDLE_TIMEOUT_USEC (5*USEC_PER_SEC)
#define IDLE_TIMEOUT2_USEC (1*USEC_PER_SEC)
/* This assumes there is a 'tty' group */
#define TTY_MODE 0620
#define SNDBUF_SIZE (8*1024*1024)
static int shift_fds(int fds[], unsigned n_fds) {
int start, restart_from;
if (n_fds <= 0)
return 0;
/* Modifies the fds array! (sorts it) */
assert(fds);
start = 0;
for (;;) {
int i;
restart_from = -1;
for (i = start; i < (int) n_fds; i++) {
int nfd;
/* Already at right index? */
if (fds[i] == i+3)
continue;
nfd = fcntl(fds[i], F_DUPFD, i + 3);
if (nfd < 0)
return -errno;
safe_close(fds[i]);
fds[i] = nfd;
/* Hmm, the fd we wanted isn't free? Then
* let's remember that and try again from here */
if (nfd != i+3 && restart_from < 0)
restart_from = i;
}
if (restart_from < 0)
break;
start = restart_from;
}
return 0;
}
static int flags_fds(const int fds[], unsigned n_fds, bool nonblock) {
unsigned i;
int r;
if (n_fds <= 0)
return 0;
assert(fds);
/* Drops/Sets O_NONBLOCK and FD_CLOEXEC from the file flags */
for (i = 0; i < n_fds; i++) {
r = fd_nonblock(fds[i], nonblock);
if (r < 0)
return r;
/* We unconditionally drop FD_CLOEXEC from the fds,
* since after all we want to pass these fds to our
* children */
r = fd_cloexec(fds[i], false);
if (r < 0)
return r;
}
return 0;
}
static const char *exec_context_tty_path(const ExecContext *context) {
assert(context);
if (context->stdio_as_fds)
return NULL;
if (context->tty_path)
return context->tty_path;
return "/dev/console";
}
static void exec_context_tty_reset(const ExecContext *context, const ExecParameters *p) {
const char *path;
assert(context);
path = exec_context_tty_path(context);
if (context->tty_vhangup) {
if (p && p->stdin_fd >= 0)
(void) terminal_vhangup_fd(p->stdin_fd);
else if (path)
(void) terminal_vhangup(path);
}
if (context->tty_reset) {
if (p && p->stdin_fd >= 0)
(void) reset_terminal_fd(p->stdin_fd, true);
else if (path)
(void) reset_terminal(path);
}
if (context->tty_vt_disallocate && path)
(void) vt_disallocate(path);
}
static bool is_terminal_input(ExecInput i) {
return IN_SET(i,
EXEC_INPUT_TTY,
EXEC_INPUT_TTY_FORCE,
EXEC_INPUT_TTY_FAIL);
}
static bool is_terminal_output(ExecOutput o) {
return IN_SET(o,
EXEC_OUTPUT_TTY,
EXEC_OUTPUT_SYSLOG_AND_CONSOLE,
EXEC_OUTPUT_KMSG_AND_CONSOLE,
EXEC_OUTPUT_JOURNAL_AND_CONSOLE);
}
static bool exec_context_needs_term(const ExecContext *c) {
assert(c);
/* Return true if the execution context suggests we should set $TERM to something useful. */
if (is_terminal_input(c->std_input))
return true;
if (is_terminal_output(c->std_output))
return true;
if (is_terminal_output(c->std_error))
return true;
return !!c->tty_path;
}
static int open_null_as(int flags, int nfd) {
int fd, r;
assert(nfd >= 0);
fd = open("/dev/null", flags|O_NOCTTY);
if (fd < 0)
return -errno;
if (fd != nfd) {
r = dup2(fd, nfd) < 0 ? -errno : nfd;
safe_close(fd);
} else
r = nfd;
return r;
}
static int connect_journal_socket(int fd, uid_t uid, gid_t gid) {
union sockaddr_union sa = {
.un.sun_family = AF_UNIX,
.un.sun_path = "/run/systemd/journal/stdout",
};
uid_t olduid = UID_INVALID;
gid_t oldgid = GID_INVALID;
int r;
if (gid != GID_INVALID) {
oldgid = getgid();
r = setegid(gid);
if (r < 0)
return -errno;
}
if (uid != UID_INVALID) {
olduid = getuid();
r = seteuid(uid);
if (r < 0) {
r = -errno;
goto restore_gid;
}
}
r = connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un));
if (r < 0)
r = -errno;
/* If we fail to restore the uid or gid, things will likely
fail later on. This should only happen if an LSM interferes. */
if (uid != UID_INVALID)
(void) seteuid(olduid);
restore_gid:
if (gid != GID_INVALID)
(void) setegid(oldgid);
return r;
}
static int connect_logger_as(
Unit *unit,
const ExecContext *context,
ExecOutput output,
const char *ident,
int nfd,
uid_t uid,
gid_t gid) {
int fd, r;
assert(context);
assert(output < _EXEC_OUTPUT_MAX);
assert(ident);
assert(nfd >= 0);
fd = socket(AF_UNIX, SOCK_STREAM, 0);
if (fd < 0)
return -errno;
r = connect_journal_socket(fd, uid, gid);
if (r < 0)
return r;
if (shutdown(fd, SHUT_RD) < 0) {
safe_close(fd);
return -errno;
}
(void) fd_inc_sndbuf(fd, SNDBUF_SIZE);
dprintf(fd,
"%s\n"
"%s\n"
"%i\n"
"%i\n"
"%i\n"
"%i\n"
"%i\n",
context->syslog_identifier ? context->syslog_identifier : ident,
unit->id,
context->syslog_priority,
!!context->syslog_level_prefix,
output == EXEC_OUTPUT_SYSLOG || output == EXEC_OUTPUT_SYSLOG_AND_CONSOLE,
output == EXEC_OUTPUT_KMSG || output == EXEC_OUTPUT_KMSG_AND_CONSOLE,
is_terminal_output(output));
if (fd == nfd)
return nfd;
r = dup2(fd, nfd) < 0 ? -errno : nfd;
safe_close(fd);
return r;
}
static int open_terminal_as(const char *path, mode_t mode, int nfd) {
int fd, r;
assert(path);
assert(nfd >= 0);
fd = open_terminal(path, mode | O_NOCTTY);
if (fd < 0)
return fd;
if (fd != nfd) {
r = dup2(fd, nfd) < 0 ? -errno : nfd;
safe_close(fd);
} else
r = nfd;
return r;
}
static int fixup_input(ExecInput std_input, int socket_fd, bool apply_tty_stdin) {
if (is_terminal_input(std_input) && !apply_tty_stdin)
return EXEC_INPUT_NULL;
if (std_input == EXEC_INPUT_SOCKET && socket_fd < 0)
return EXEC_INPUT_NULL;
return std_input;
}
static int fixup_output(ExecOutput std_output, int socket_fd) {
if (std_output == EXEC_OUTPUT_SOCKET && socket_fd < 0)
return EXEC_OUTPUT_INHERIT;
return std_output;
}
static int setup_input(
const ExecContext *context,
const ExecParameters *params,
int socket_fd,
int named_iofds[3]) {
ExecInput i;
assert(context);
assert(params);
if (params->stdin_fd >= 0) {
if (dup2(params->stdin_fd, STDIN_FILENO) < 0)
return -errno;
/* Try to make this the controlling tty, if it is a tty, and reset it */
(void) ioctl(STDIN_FILENO, TIOCSCTTY, context->std_input == EXEC_INPUT_TTY_FORCE);
(void) reset_terminal_fd(STDIN_FILENO, true);
return STDIN_FILENO;
}
i = fixup_input(context->std_input, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
switch (i) {
case EXEC_INPUT_NULL:
return open_null_as(O_RDONLY, STDIN_FILENO);
case EXEC_INPUT_TTY:
case EXEC_INPUT_TTY_FORCE:
case EXEC_INPUT_TTY_FAIL: {
int fd, r;
fd = acquire_terminal(exec_context_tty_path(context),
i == EXEC_INPUT_TTY_FAIL,
i == EXEC_INPUT_TTY_FORCE,
false,
USEC_INFINITY);
if (fd < 0)
return fd;
if (fd != STDIN_FILENO) {
r = dup2(fd, STDIN_FILENO) < 0 ? -errno : STDIN_FILENO;
safe_close(fd);
} else
r = STDIN_FILENO;
return r;
}
case EXEC_INPUT_SOCKET:
return dup2(socket_fd, STDIN_FILENO) < 0 ? -errno : STDIN_FILENO;
case EXEC_INPUT_NAMED_FD:
(void) fd_nonblock(named_iofds[STDIN_FILENO], false);
return dup2(named_iofds[STDIN_FILENO], STDIN_FILENO) < 0 ? -errno : STDIN_FILENO;
default:
assert_not_reached("Unknown input type");
}
}
static int setup_output(
Unit *unit,
const ExecContext *context,
const ExecParameters *params,
int fileno,
int socket_fd,
int named_iofds[3],
const char *ident,
uid_t uid,
gid_t gid,
dev_t *journal_stream_dev,
ino_t *journal_stream_ino) {
ExecOutput o;
ExecInput i;
int r;
assert(unit);
assert(context);
assert(params);
assert(ident);
assert(journal_stream_dev);
assert(journal_stream_ino);
if (fileno == STDOUT_FILENO && params->stdout_fd >= 0) {
if (dup2(params->stdout_fd, STDOUT_FILENO) < 0)
return -errno;
return STDOUT_FILENO;
}
if (fileno == STDERR_FILENO && params->stderr_fd >= 0) {
if (dup2(params->stderr_fd, STDERR_FILENO) < 0)
return -errno;
return STDERR_FILENO;
}
i = fixup_input(context->std_input, socket_fd, params->flags & EXEC_APPLY_TTY_STDIN);
o = fixup_output(context->std_output, socket_fd);
if (fileno == STDERR_FILENO) {
ExecOutput e;
e = fixup_output(context->std_error, socket_fd);
/* This expects the input and output are already set up */
/* Don't change the stderr file descriptor if we inherit all
* the way and are not on a tty */
if (e == EXEC_OUTPUT_INHERIT &&
o == EXEC_OUTPUT_INHERIT &&
i == EXEC_INPUT_NULL &&
!is_terminal_input(context->std_input) &&
getppid () != 1)
return fileno;
/* Duplicate from stdout if possible */
if ((e == o && e != EXEC_OUTPUT_NAMED_FD) || e == EXEC_OUTPUT_INHERIT)
return dup2(STDOUT_FILENO, fileno) < 0 ? -errno : fileno;
o = e;
} else if (o == EXEC_OUTPUT_INHERIT) {
/* If input got downgraded, inherit the original value */
if (i == EXEC_INPUT_NULL && is_terminal_input(context->std_input))
return open_terminal_as(exec_context_tty_path(context), O_WRONLY, fileno);
/* If the input is connected to anything that's not a /dev/null, inherit that... */
if (i != EXEC_INPUT_NULL)
return dup2(STDIN_FILENO, fileno) < 0 ? -errno : fileno;
/* If we are not started from PID 1 we just inherit STDOUT from our parent process. */
if (getppid() != 1)
return fileno;
/* We need to open /dev/null here anew, to get the right access mode. */
return open_null_as(O_WRONLY, fileno);
}
switch (o) {
case EXEC_OUTPUT_NULL:
return open_null_as(O_WRONLY, fileno);
case EXEC_OUTPUT_TTY:
if (is_terminal_input(i))
return dup2(STDIN_FILENO, fileno) < 0 ? -errno : fileno;
/* We don't reset the terminal if this is just about output */
return open_terminal_as(exec_context_tty_path(context), O_WRONLY, fileno);
case EXEC_OUTPUT_SYSLOG:
case EXEC_OUTPUT_SYSLOG_AND_CONSOLE:
case EXEC_OUTPUT_KMSG:
case EXEC_OUTPUT_KMSG_AND_CONSOLE:
case EXEC_OUTPUT_JOURNAL:
case EXEC_OUTPUT_JOURNAL_AND_CONSOLE:
r = connect_logger_as(unit, context, o, ident, fileno, uid, gid);
if (r < 0) {
log_unit_error_errno(unit, r, "Failed to connect %s to the journal socket, ignoring: %m", fileno == STDOUT_FILENO ? "stdout" : "stderr");
r = open_null_as(O_WRONLY, fileno);
} else {
struct stat st;
/* If we connected this fd to the journal via a stream, patch the device/inode into the passed
* parameters, but only then. This is useful so that we can set $JOURNAL_STREAM that permits
* services to detect whether they are connected to the journal or not. */
if (fstat(fileno, &st) >= 0) {
*journal_stream_dev = st.st_dev;
*journal_stream_ino = st.st_ino;
}
}
return r;
case EXEC_OUTPUT_SOCKET:
assert(socket_fd >= 0);
return dup2(socket_fd, fileno) < 0 ? -errno : fileno;
case EXEC_OUTPUT_NAMED_FD:
(void) fd_nonblock(named_iofds[fileno], false);
return dup2(named_iofds[fileno], fileno) < 0 ? -errno : fileno;
default:
assert_not_reached("Unknown error type");
}
}
static int chown_terminal(int fd, uid_t uid) {
struct stat st;
assert(fd >= 0);
/* Before we chown/chmod the TTY, let's ensure this is actually a tty */
if (isatty(fd) < 1)
return 0;
/* This might fail. What matters are the results. */
(void) fchown(fd, uid, -1);
(void) fchmod(fd, TTY_MODE);
if (fstat(fd, &st) < 0)
return -errno;
if (st.st_uid != uid || (st.st_mode & 0777) != TTY_MODE)
return -EPERM;
return 0;
}
static int setup_confirm_stdio(const char *vc, int *_saved_stdin, int *_saved_stdout) {
_cleanup_close_ int fd = -1, saved_stdin = -1, saved_stdout = -1;
int r;
assert(_saved_stdin);
assert(_saved_stdout);
saved_stdin = fcntl(STDIN_FILENO, F_DUPFD, 3);
if (saved_stdin < 0)
return -errno;
saved_stdout = fcntl(STDOUT_FILENO, F_DUPFD, 3);
if (saved_stdout < 0)
return -errno;
fd = acquire_terminal(vc, false, false, false, DEFAULT_CONFIRM_USEC);
if (fd < 0)
return fd;
r = chown_terminal(fd, getuid());
if (r < 0)
return r;
r = reset_terminal_fd(fd, true);
if (r < 0)
return r;
if (dup2(fd, STDIN_FILENO) < 0)
return -errno;
if (dup2(fd, STDOUT_FILENO) < 0)
return -errno;
if (fd >= 2)
safe_close(fd);
fd = -1;
*_saved_stdin = saved_stdin;
*_saved_stdout = saved_stdout;
saved_stdin = saved_stdout = -1;
return 0;
}
static void write_confirm_error_fd(int err, int fd, const Unit *u) {
assert(err < 0);
if (err == -ETIMEDOUT)
dprintf(fd, "Confirmation question timed out for %s, assuming positive response.\n", u->id);
else {
errno = -err;
dprintf(fd, "Couldn't ask confirmation for %s: %m, assuming positive response.\n", u->id);
}
}
static void write_confirm_error(int err, const char *vc, const Unit *u) {
_cleanup_close_ int fd = -1;
assert(vc);
fd = open_terminal(vc, O_WRONLY|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return;
write_confirm_error_fd(err, fd, u);
}
static int restore_confirm_stdio(int *saved_stdin, int *saved_stdout) {
int r = 0;
assert(saved_stdin);
assert(saved_stdout);
release_terminal();
if (*saved_stdin >= 0)
if (dup2(*saved_stdin, STDIN_FILENO) < 0)
r = -errno;
if (*saved_stdout >= 0)
if (dup2(*saved_stdout, STDOUT_FILENO) < 0)
r = -errno;
*saved_stdin = safe_close(*saved_stdin);
*saved_stdout = safe_close(*saved_stdout);
return r;
}
enum {
CONFIRM_PRETEND_FAILURE = -1,
CONFIRM_PRETEND_SUCCESS = 0,
CONFIRM_EXECUTE = 1,
};
static int ask_for_confirmation(const char *vc, Unit *u, const char *cmdline) {
int saved_stdout = -1, saved_stdin = -1, r;
_cleanup_free_ char *e = NULL;
char c;
/* For any internal errors, assume a positive response. */
r = setup_confirm_stdio(vc, &saved_stdin, &saved_stdout);
if (r < 0) {
write_confirm_error(r, vc, u);
return CONFIRM_EXECUTE;
}
/* confirm_spawn might have been disabled while we were sleeping. */
if (manager_is_confirm_spawn_disabled(u->manager)) {
r = 1;
goto restore_stdio;
}
e = ellipsize(cmdline, 60, 100);
if (!e) {
log_oom();
r = CONFIRM_EXECUTE;
goto restore_stdio;
}
for (;;) {
r = ask_char(&c, "yfshiDjcn", "Execute %s? [y, f, s – h for help] ", e);
if (r < 0) {
write_confirm_error_fd(r, STDOUT_FILENO, u);
r = CONFIRM_EXECUTE;
goto restore_stdio;
}
switch (c) {
case 'c':
printf("Resuming normal execution.\n");
manager_disable_confirm_spawn();
r = 1;
break;
case 'D':
unit_dump(u, stdout, " ");
continue; /* ask again */
case 'f':
printf("Failing execution.\n");
r = CONFIRM_PRETEND_FAILURE;
break;
case 'h':
printf(" c - continue, proceed without asking anymore\n"
" D - dump, show the state of the unit\n"
" f - fail, don't execute the command and pretend it failed\n"
" h - help\n"
" i - info, show a short summary of the unit\n"
" j - jobs, show jobs that are in progress\n"
" s - skip, don't execute the command and pretend it succeeded\n"
" y - yes, execute the command\n");
continue; /* ask again */
case 'i':
printf(" Description: %s\n"
" Unit: %s\n"
" Command: %s\n",
u->id, u->description, cmdline);
continue; /* ask again */
case 'j':
manager_dump_jobs(u->manager, stdout, " ");
continue; /* ask again */
case 'n':
/* 'n' was removed in favor of 'f'. */
printf("Didn't understand 'n', did you mean 'f'?\n");
continue; /* ask again */
case 's':
printf("Skipping execution.\n");
r = CONFIRM_PRETEND_SUCCESS;
break;
case 'y':
r = CONFIRM_EXECUTE;
break;
default:
assert_not_reached("Unhandled choice");
}
break;
}
restore_stdio:
restore_confirm_stdio(&saved_stdin, &saved_stdout);
return r;
}
static int get_fixed_user(const ExecContext *c, const char **user,
uid_t *uid, gid_t *gid,
const char **home, const char **shell) {
int r;
const char *name;
assert(c);
if (!c->user)
return 0;
/* Note that we don't set $HOME or $SHELL if they are not particularly enlightening anyway
* (i.e. are "/" or "/bin/nologin"). */
name = c->user;
r = get_user_creds_clean(&name, uid, gid, home, shell);
if (r < 0)
return r;
*user = name;
return 0;
}
static int get_fixed_group(const ExecContext *c, const char **group, gid_t *gid) {
int r;
const char *name;
assert(c);
if (!c->group)
return 0;
name = c->group;
r = get_group_creds(&name, gid);
if (r < 0)
return r;
*group = name;
return 0;
}
static int get_supplementary_groups(const ExecContext *c, const char *user,
const char *group, gid_t gid,
gid_t **supplementary_gids, int *ngids) {
char **i;
int r, k = 0;
int ngroups_max;
bool keep_groups = false;
gid_t *groups = NULL;
_cleanup_free_ gid_t *l_gids = NULL;
assert(c);
/*
* If user is given, then lookup GID and supplementary groups list.
* We avoid NSS lookups for gid=0. Also we have to initialize groups
* here and as early as possible so we keep the list of supplementary
* groups of the caller.
*/
if (user && gid_is_valid(gid) && gid != 0) {
/* First step, initialize groups from /etc/groups */
if (initgroups(user, gid) < 0)
return -errno;
keep_groups = true;
}
if (!c->supplementary_groups)
return 0;
/*
* If SupplementaryGroups= was passed then NGROUPS_MAX has to
* be positive, otherwise fail.
*/
errno = 0;
ngroups_max = (int) sysconf(_SC_NGROUPS_MAX);
if (ngroups_max <= 0) {
if (errno > 0)
return -errno;
else
return -EOPNOTSUPP; /* For all other values */
}
l_gids = new(gid_t, ngroups_max);
if (!l_gids)
return -ENOMEM;
if (keep_groups) {
/*
* Lookup the list of groups that the user belongs to, we
* avoid NSS lookups here too for gid=0.
*/
k = ngroups_max;
if (getgrouplist(user, gid, l_gids, &k) < 0)
return -EINVAL;
} else
k = 0;
STRV_FOREACH(i, c->supplementary_groups) {
const char *g;
if (k >= ngroups_max)
return -E2BIG;
g = *i;
r = get_group_creds(&g, l_gids+k);
if (r < 0)
return r;
k++;
}
/*
* Sets ngids to zero to drop all supplementary groups, happens
* when we are under root and SupplementaryGroups= is empty.
*/
if (k == 0) {
*ngids = 0;
return 0;
}
/* Otherwise get the final list of supplementary groups */
groups = memdup(l_gids, sizeof(gid_t) * k);
if (!groups)
return -ENOMEM;
*supplementary_gids = groups;
*ngids = k;
groups = NULL;
return 0;
}
static int enforce_groups(const ExecContext *context, gid_t gid,
gid_t *supplementary_gids, int ngids) {
int r;
assert(context);
/* Handle SupplementaryGroups= even if it is empty */
if (context->supplementary_groups) {
r = maybe_setgroups(ngids, supplementary_gids);
if (r < 0)
return r;
}
if (gid_is_valid(gid)) {
/* Then set our gids */
if (setresgid(gid, gid, gid) < 0)
return -errno;
}
return 0;
}
static int enforce_user(const ExecContext *context, uid_t uid) {
assert(context);
if (!uid_is_valid(uid))
return 0;
/* Sets (but doesn't look up) the uid and make sure we keep the
* capabilities while doing so. */
if (context->capability_ambient_set != 0) {
/* First step: If we need to keep capabilities but
* drop privileges we need to make sure we keep our
* caps, while we drop privileges. */
if (uid != 0) {
int sb = context->secure_bits | 1<<SECURE_KEEP_CAPS;
if (prctl(PR_GET_SECUREBITS) != sb)
if (prctl(PR_SET_SECUREBITS, sb) < 0)
return -errno;
}
}
/* Second step: actually set the uids */
if (setresuid(uid, uid, uid) < 0)
return -errno;
/* At this point we should have all necessary capabilities but
are otherwise a normal user. However, the caps might got
corrupted due to the setresuid() so we need clean them up
later. This is done outside of this call. */
return 0;
}
#ifdef HAVE_PAM
static int null_conv(
int num_msg,
const struct pam_message **msg,
struct pam_response **resp,
void *appdata_ptr) {
/* We don't support conversations */
return PAM_CONV_ERR;
}
#endif
static int setup_pam(
const char *name,
const char *user,
uid_t uid,
gid_t gid,
const char *tty,
char ***env,
int fds[], unsigned n_fds) {
#ifdef HAVE_PAM
static const struct pam_conv conv = {
.conv = null_conv,
.appdata_ptr = NULL
};
_cleanup_(barrier_destroy) Barrier barrier = BARRIER_NULL;
pam_handle_t *handle = NULL;
sigset_t old_ss;
int pam_code = PAM_SUCCESS, r;
char **nv, **e = NULL;
bool close_session = false;
pid_t pam_pid = 0, parent_pid;
int flags = 0;
assert(name);
assert(user);
assert(env);
/* We set up PAM in the parent process, then fork. The child
* will then stay around until killed via PR_GET_PDEATHSIG or
* systemd via the cgroup logic. It will then remove the PAM
* session again. The parent process will exec() the actual
* daemon. We do things this way to ensure that the main PID
* of the daemon is the one we initially fork()ed. */
r = barrier_create(&barrier);
if (r < 0)
goto fail;
if (log_get_max_level() < LOG_DEBUG)
flags |= PAM_SILENT;
pam_code = pam_start(name, user, &conv, &handle);
if (pam_code != PAM_SUCCESS) {
handle = NULL;
goto fail;
}
if (tty) {
pam_code = pam_set_item(handle, PAM_TTY, tty);
if (pam_code != PAM_SUCCESS)
goto fail;
}
STRV_FOREACH(nv, *env) {
pam_code = pam_putenv(handle, *nv);
if (pam_code != PAM_SUCCESS)
goto fail;
}
pam_code = pam_acct_mgmt(handle, flags);
if (pam_code != PAM_SUCCESS)
goto fail;
pam_code = pam_open_session(handle, flags);
if (pam_code != PAM_SUCCESS)
goto fail;
close_session = true;
e = pam_getenvlist(handle);
if (!e) {
pam_code = PAM_BUF_ERR;
goto fail;
}
/* Block SIGTERM, so that we know that it won't get lost in
* the child */
assert_se(sigprocmask_many(SIG_BLOCK, &old_ss, SIGTERM, -1) >= 0);
parent_pid = getpid();
pam_pid = fork();
if (pam_pid < 0) {
r = -errno;
goto fail;
}
if (pam_pid == 0) {
int sig, ret = EXIT_PAM;
/* The child's job is to reset the PAM session on
* termination */
barrier_set_role(&barrier, BARRIER_CHILD);
/* This string must fit in 10 chars (i.e. the length
* of "/sbin/init"), to look pretty in /bin/ps */
rename_process("(sd-pam)");
/* Make sure we don't keep open the passed fds in this
child. We assume that otherwise only those fds are
open here that have been opened by PAM. */
close_many(fds, n_fds);
/* Drop privileges - we don't need any to pam_close_session
* and this will make PR_SET_PDEATHSIG work in most cases.
* If this fails, ignore the error - but expect sd-pam threads
* to fail to exit normally */
r = maybe_setgroups(0, NULL);
if (r < 0)
log_warning_errno(r, "Failed to setgroups() in sd-pam: %m");
if (setresgid(gid, gid, gid) < 0)
log_warning_errno(errno, "Failed to setresgid() in sd-pam: %m");
if (setresuid(uid, uid, uid) < 0)
log_warning_errno(errno, "Failed to setresuid() in sd-pam: %m");
(void) ignore_signals(SIGPIPE, -1);
/* Wait until our parent died. This will only work if
* the above setresuid() succeeds, otherwise the kernel
* will not allow unprivileged parents kill their privileged
* children this way. We rely on the control groups kill logic
* to do the rest for us. */
if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
goto child_finish;
/* Tell the parent that our setup is done. This is especially
* important regarding dropping privileges. Otherwise, unit
* setup might race against our setresuid(2) call. */
barrier_place(&barrier);
/* Check if our parent process might already have
* died? */
if (getppid() == parent_pid) {
sigset_t ss;
assert_se(sigemptyset(&ss) >= 0);
assert_se(sigaddset(&ss, SIGTERM) >= 0);
for (;;) {
if (sigwait(&ss, &sig) < 0) {
if (errno == EINTR)
continue;
goto child_finish;
}
assert(sig == SIGTERM);
break;
}
}
/* If our parent died we'll end the session */
if (getppid() != parent_pid) {
pam_code = pam_close_session(handle, flags);
if (pam_code != PAM_SUCCESS)
goto child_finish;
}
ret = 0;
child_finish:
pam_end(handle, pam_code | flags);
_exit(ret);
}
barrier_set_role(&barrier, BARRIER_PARENT);
/* If the child was forked off successfully it will do all the
* cleanups, so forget about the handle here. */
handle = NULL;
/* Unblock SIGTERM again in the parent */
assert_se(sigprocmask(SIG_SETMASK, &old_ss, NULL) >= 0);
/* We close the log explicitly here, since the PAM modules
* might have opened it, but we don't want this fd around. */
closelog();
/* Synchronously wait for the child to initialize. We don't care for
* errors as we cannot recover. However, warn loudly if it happens. */
if (!barrier_place_and_sync(&barrier))
log_error("PAM initialization failed");
strv_free(*env);
*env = e;
return 0;
fail:
if (pam_code != PAM_SUCCESS) {
log_error("PAM failed: %s", pam_strerror(handle, pam_code));
r = -EPERM; /* PAM errors do not map to errno */
} else
log_error_errno(r, "PAM failed: %m");
if (handle) {
if (close_session)
pam_code = pam_close_session(handle, flags);
pam_end(handle, pam_code | flags);
}
strv_free(e);
closelog();
return r;
#else
return 0;
#endif
}
static void rename_process_from_path(const char *path) {
char process_name[11];
const char *p;
size_t l;
/* This resulting string must fit in 10 chars (i.e. the length
* of "/sbin/init") to look pretty in /bin/ps */
p = basename(path);
if (isempty(p)) {
rename_process("(...)");
return;
}
l = strlen(p);
if (l > 8) {
/* The end of the process name is usually more
* interesting, since the first bit might just be
* "systemd-" */
p = p + l - 8;
l = 8;
}
process_name[0] = '(';
memcpy(process_name+1, p, l);
process_name[1+l] = ')';
process_name[1+l+1] = 0;
rename_process(process_name);
}
#ifdef HAVE_SECCOMP
static bool skip_seccomp_unavailable(const Unit* u, const char* msg) {
if (is_seccomp_available())
return false;
log_open();
log_unit_debug(u, "SECCOMP features not detected in the kernel, skipping %s", msg);
log_close();
return true;
}
static int apply_seccomp(const Unit* u, const ExecContext *c) {
uint32_t negative_action, action;
scmp_filter_ctx seccomp;
Iterator i;
void *id;
int r;
assert(c);
if (skip_seccomp_unavailable(u, "syscall filtering"))
return 0;
negative_action = c->syscall_errno == 0 ? SCMP_ACT_KILL : SCMP_ACT_ERRNO(c->syscall_errno);
seccomp = seccomp_init(c->syscall_whitelist ? negative_action : SCMP_ACT_ALLOW);
if (!seccomp)
return -ENOMEM;
if (c->syscall_archs) {
SET_FOREACH(id, c->syscall_archs, i) {
r = seccomp_arch_add(seccomp, PTR_TO_UINT32(id) - 1);
if (r == -EEXIST)
continue;
if (r < 0)
goto finish;
}
} else {
r = seccomp_add_secondary_archs(seccomp);
if (r < 0)
goto finish;
}
action = c->syscall_whitelist ? SCMP_ACT_ALLOW : negative_action;
SET_FOREACH(id, c->syscall_filter, i) {
r = seccomp_rule_add(seccomp, action, PTR_TO_INT(id) - 1, 0);
if (r < 0)
goto finish;
}
r = seccomp_attr_set(seccomp, SCMP_FLTATR_CTL_NNP, 0);
if (r < 0)
goto finish;
r = seccomp_load(seccomp);
finish:
seccomp_release(seccomp);
return r;
}
static int apply_address_families(const Unit* u, const ExecContext *c) {
scmp_filter_ctx seccomp;
Iterator i;
int r;
assert(c);
if (skip_seccomp_unavailable(u, "RestrictAddressFamilies="))
return 0;
r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
if (r < 0)
return r;
if (c->address_families_whitelist) {
int af, first = 0, last = 0;
void *afp;
/* If this is a whitelist, we first block the address
* families that are out of range and then everything
* that is not in the set. First, we find the lowest
* and highest address family in the set. */
SET_FOREACH(afp, c->address_families, i) {
af = PTR_TO_INT(afp);
if (af <= 0 || af >= af_max())
continue;
if (first == 0 || af < first)
first = af;
if (last == 0 || af > last)
last = af;
}
assert((first == 0) == (last == 0));
if (first == 0) {
/* No entries in the valid range, block everything */
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPROTONOSUPPORT),
SCMP_SYS(socket),
0);
if (r < 0)
goto finish;
} else {
/* Block everything below the first entry */
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPROTONOSUPPORT),
SCMP_SYS(socket),
1,
SCMP_A0(SCMP_CMP_LT, first));
if (r < 0)
goto finish;
/* Block everything above the last entry */
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPROTONOSUPPORT),
SCMP_SYS(socket),
1,
SCMP_A0(SCMP_CMP_GT, last));
if (r < 0)
goto finish;
/* Block everything between the first and last
* entry */
for (af = 1; af < af_max(); af++) {
if (set_contains(c->address_families, INT_TO_PTR(af)))
continue;
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPROTONOSUPPORT),
SCMP_SYS(socket),
1,
SCMP_A0(SCMP_CMP_EQ, af));
if (r < 0)
goto finish;
}
}
} else {
void *af;
/* If this is a blacklist, then generate one rule for
* each address family that are then combined in OR
* checks. */
SET_FOREACH(af, c->address_families, i) {
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPROTONOSUPPORT),
SCMP_SYS(socket),
1,
SCMP_A0(SCMP_CMP_EQ, PTR_TO_INT(af)));
if (r < 0)
goto finish;
}
}
r = seccomp_load(seccomp);
finish:
seccomp_release(seccomp);
return r;
}
static int apply_memory_deny_write_execute(const Unit* u, const ExecContext *c) {
scmp_filter_ctx seccomp;
int r;
assert(c);
if (skip_seccomp_unavailable(u, "MemoryDenyWriteExecute="))
return 0;
r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
if (r < 0)
return r;
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPERM),
SCMP_SYS(mmap),
1,
SCMP_A2(SCMP_CMP_MASKED_EQ, PROT_EXEC|PROT_WRITE, PROT_EXEC|PROT_WRITE));
if (r < 0)
goto finish;
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPERM),
SCMP_SYS(mprotect),
1,
SCMP_A2(SCMP_CMP_MASKED_EQ, PROT_EXEC, PROT_EXEC));
if (r < 0)
goto finish;
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPERM),
SCMP_SYS(shmat),
1,
SCMP_A2(SCMP_CMP_MASKED_EQ, SHM_EXEC, SHM_EXEC));
if (r < 0)
goto finish;
r = seccomp_load(seccomp);
finish:
seccomp_release(seccomp);
return r;
}
static int apply_restrict_realtime(const Unit* u, const ExecContext *c) {
static const int permitted_policies[] = {
SCHED_OTHER,
SCHED_BATCH,
SCHED_IDLE,
};
scmp_filter_ctx seccomp;
unsigned i;
int r, p, max_policy = 0;
assert(c);
if (skip_seccomp_unavailable(u, "RestrictRealtime="))
return 0;
r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
if (r < 0)
return r;
/* Determine the highest policy constant we want to allow */
for (i = 0; i < ELEMENTSOF(permitted_policies); i++)
if (permitted_policies[i] > max_policy)
max_policy = permitted_policies[i];
/* Go through all policies with lower values than that, and block them -- unless they appear in the
* whitelist. */
for (p = 0; p < max_policy; p++) {
bool good = false;
/* Check if this is in the whitelist. */
for (i = 0; i < ELEMENTSOF(permitted_policies); i++)
if (permitted_policies[i] == p) {
good = true;
break;
}
if (good)
continue;
/* Deny this policy */
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPERM),
SCMP_SYS(sched_setscheduler),
1,
SCMP_A1(SCMP_CMP_EQ, p));
if (r < 0)
goto finish;
}
/* Blacklist all other policies, i.e. the ones with higher values. Note that all comparisons are unsigned here,
* hence no need no check for < 0 values. */
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPERM),
SCMP_SYS(sched_setscheduler),
1,
SCMP_A1(SCMP_CMP_GT, max_policy));
if (r < 0)
goto finish;
r = seccomp_load(seccomp);
finish:
seccomp_release(seccomp);
return r;
}
static int apply_protect_sysctl(const Unit *u, const ExecContext *c) {
scmp_filter_ctx seccomp;
int r;
assert(c);
/* Turn off the legacy sysctl() system call. Many distributions turn this off while building the kernel, but
* let's protect even those systems where this is left on in the kernel. */
if (skip_seccomp_unavailable(u, "ProtectKernelTunables="))
return 0;
r = seccomp_init_conservative(&seccomp, SCMP_ACT_ALLOW);
if (r < 0)
return r;
r = seccomp_rule_add(
seccomp,
SCMP_ACT_ERRNO(EPERM),
SCMP_SYS(_sysctl),
0);
if (r < 0)
goto finish;
r = seccomp_load(seccomp);
finish:
seccomp_release(seccomp);
return r;
}
static int apply_protect_kernel_modules(const Unit *u, const ExecContext *c) {
assert(c);
/* Turn off module syscalls on ProtectKernelModules=yes */
if (skip_seccomp_unavailable(u, "ProtectKernelModules="))
return 0;
return seccomp_load_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_MODULE, SCMP_ACT_ERRNO(EPERM));
}
static int apply_private_devices(const Unit *u, const ExecContext *c) {
assert(c);
/* If PrivateDevices= is set, also turn off iopl and all @raw-io syscalls. */
if (skip_seccomp_unavailable(u, "PrivateDevices="))
return 0;
return seccomp_load_filter_set(SCMP_ACT_ALLOW, syscall_filter_sets + SYSCALL_FILTER_SET_RAW_IO, SCMP_ACT_ERRNO(EPERM));
}
static int apply_restrict_namespaces(Unit *u, const ExecContext *c) {
assert(c);
if (!exec_context_restrict_namespaces_set(c))
return 0;
if (skip_seccomp_unavailable(u, "RestrictNamespaces="))
return 0;
return seccomp_restrict_namespaces(c->restrict_namespaces);
}
#endif
static void do_idle_pipe_dance(int idle_pipe[4]) {
assert(idle_pipe);
idle_pipe[1] = safe_close(idle_pipe[1]);
idle_pipe[2] = safe_close(idle_pipe[2]);
if (idle_pipe[0] >= 0) {
int r;
r = fd_wait_for_event(idle_pipe[0], POLLHUP, IDLE_TIMEOUT_USEC);
if (idle_pipe[3] >= 0 && r == 0 /* timeout */) {
ssize_t n;
/* Signal systemd that we are bored and want to continue. */
n = write(idle_pipe[3], "x", 1);
if (n > 0)
/* Wait for systemd to react to the signal above. */
fd_wait_for_event(idle_pipe[0], POLLHUP, IDLE_TIMEOUT2_USEC);
}
idle_pipe[0] = safe_close(idle_pipe[0]);
}
idle_pipe[3] = safe_close(idle_pipe[3]);
}
static int build_environment(
Unit *u,
const ExecContext *c,
const ExecParameters *p,
unsigned n_fds,
const char *home,
const char *username,
const char *shell,
dev_t journal_stream_dev,
ino_t journal_stream_ino,
char ***ret) {
_cleanup_strv_free_ char **our_env = NULL;
unsigned n_env = 0;
char *x;
assert(u);
assert(c);
assert(ret);
our_env = new0(char*, 14);
if (!our_env)
return -ENOMEM;
if (n_fds > 0) {
_cleanup_free_ char *joined = NULL;
if (asprintf(&x, "LISTEN_PID="PID_FMT, getpid()) < 0)
return -ENOMEM;
our_env[n_env++] = x;
if (asprintf(&x, "LISTEN_FDS=%u", n_fds) < 0)
return -ENOMEM;
our_env[n_env++] = x;
joined = strv_join(p->fd_names, ":");
if (!joined)
return -ENOMEM;
x = strjoin("LISTEN_FDNAMES=", joined);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
if ((p->flags & EXEC_SET_WATCHDOG) && p->watchdog_usec > 0) {
if (asprintf(&x, "WATCHDOG_PID="PID_FMT, getpid()) < 0)
return -ENOMEM;
our_env[n_env++] = x;
if (asprintf(&x, "WATCHDOG_USEC="USEC_FMT, p->watchdog_usec) < 0)
return -ENOMEM;
our_env[n_env++] = x;
}
/* If this is D-Bus, tell the nss-systemd module, since it relies on being able to use D-Bus look up dynamic
* users via PID 1, possibly dead-locking the dbus daemon. This way it will not use D-Bus to resolve names, but
* check the database directly. */
if (unit_has_name(u, SPECIAL_DBUS_SERVICE)) {
x = strdup("SYSTEMD_NSS_BYPASS_BUS=1");
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
if (home) {
x = strappend("HOME=", home);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
if (username) {
x = strappend("LOGNAME=", username);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
x = strappend("USER=", username);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
if (shell) {
x = strappend("SHELL=", shell);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
if (!sd_id128_is_null(u->invocation_id)) {
if (asprintf(&x, "INVOCATION_ID=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(u->invocation_id)) < 0)
return -ENOMEM;
our_env[n_env++] = x;
}
if (exec_context_needs_term(c)) {
const char *tty_path, *term = NULL;
tty_path = exec_context_tty_path(c);
/* If we are forked off PID 1 and we are supposed to operate on /dev/console, then let's try to inherit
* the $TERM set for PID 1. This is useful for containers so that the $TERM the container manager
* passes to PID 1 ends up all the way in the console login shown. */
if (path_equal(tty_path, "/dev/console") && getppid() == 1)
term = getenv("TERM");
if (!term)
term = default_term_for_tty(tty_path);
x = strappend("TERM=", term);
if (!x)
return -ENOMEM;
our_env[n_env++] = x;
}
if (journal_stream_dev != 0 && journal_stream_ino != 0) {
if (asprintf(&x, "JOURNAL_STREAM=" DEV_FMT ":" INO_FMT, journal_stream_dev, journal_stream_ino) < 0)
return -ENOMEM;
our_env[n_env++] = x;
}
our_env[n_env++] = NULL;
assert(n_env <= 12);
*ret = our_env;
our_env = NULL;
return 0;
}
static int build_pass_environment(const ExecContext *c, char ***ret) {
_cleanup_strv_free_ char **pass_env = NULL;
size_t n_env = 0, n_bufsize = 0;
char **i;
STRV_FOREACH(i, c->pass_environment) {
_cleanup_free_ char *x = NULL;
char *v;
v = getenv(*i);
if (!v)
continue;
x = strjoin(*i, "=", v);
if (!x)
return -ENOMEM;
if (!GREEDY_REALLOC(pass_env, n_bufsize, n_env + 2))
return -ENOMEM;
pass_env[n_env++] = x;
pass_env[n_env] = NULL;
x = NULL;
}
*ret = pass_env;
pass_env = NULL;
return 0;
}
static bool exec_needs_mount_namespace(
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime) {
assert(context);
assert(params);
if (!strv_isempty(context->read_write_paths) ||
!strv_isempty(context->read_only_paths) ||
!strv_isempty(context->inaccessible_paths))
return true;
if (context->n_bind_mounts > 0)
return true;
if (context->mount_flags != 0)
return true;
if (context->private_tmp && runtime && (runtime->tmp_dir || runtime->var_tmp_dir))
return true;
if (context->private_devices ||
context->protect_system != PROTECT_SYSTEM_NO ||
context->protect_home != PROTECT_HOME_NO ||
context->protect_kernel_tunables ||
context->protect_kernel_modules ||
context->protect_control_groups)
return true;
return false;
}
static int setup_private_users(uid_t uid, gid_t gid) {
_cleanup_free_ char *uid_map = NULL, *gid_map = NULL;
_cleanup_close_pair_ int errno_pipe[2] = { -1, -1 };
_cleanup_close_ int unshare_ready_fd = -1;
_cleanup_(sigkill_waitp) pid_t pid = 0;
uint64_t c = 1;
siginfo_t si;
ssize_t n;
int r;
/* Set up a user namespace and map root to root, the selected UID/GID to itself, and everything else to
* nobody. In order to be able to write this mapping we need CAP_SETUID in the original user namespace, which
* we however lack after opening the user namespace. To work around this we fork() a temporary child process,
* which waits for the parent to create the new user namespace while staying in the original namespace. The
* child then writes the UID mapping, under full privileges. The parent waits for the child to finish and
* continues execution normally. */
if (uid != 0 && uid_is_valid(uid))
asprintf(&uid_map,
"0 0 1\n" /* Map root → root */
UID_FMT " " UID_FMT " 1\n", /* Map $UID → $UID */
uid, uid);
else
uid_map = strdup("0 0 1\n"); /* The case where the above is the same */
if (!uid_map)
return -ENOMEM;
if (gid != 0 && gid_is_valid(gid))
asprintf(&gid_map,
"0 0 1\n" /* Map root → root */
GID_FMT " " GID_FMT " 1\n", /* Map $GID → $GID */
gid, gid);
else
gid_map = strdup("0 0 1\n"); /* The case where the above is the same */
if (!gid_map)
return -ENOMEM;
/* Create a communication channel so that the parent can tell the child when it finished creating the user
* namespace. */
unshare_ready_fd = eventfd(0, EFD_CLOEXEC);
if (unshare_ready_fd < 0)
return -errno;
/* Create a communication channel so that the child can tell the parent a proper error code in case it
* failed. */
if (pipe2(errno_pipe, O_CLOEXEC) < 0)
return -errno;
pid = fork();
if (pid < 0)
return -errno;
if (pid == 0) {
_cleanup_close_ int fd = -1;
const char *a;
pid_t ppid;
/* Child process, running in the original user namespace. Let's update the parent's UID/GID map from
* here, after the parent opened its own user namespace. */
ppid = getppid();
errno_pipe[0] = safe_close(errno_pipe[0]);
/* Wait until the parent unshared the user namespace */
if (read(unshare_ready_fd, &c, sizeof(c)) < 0) {
r = -errno;
goto child_fail;
}
/* Disable the setgroups() system call in the child user namespace, for good. */
a = procfs_file_alloca(ppid, "setgroups");
fd = open(a, O_WRONLY|O_CLOEXEC);
if (fd < 0) {
if (errno != ENOENT) {
r = -errno;
goto child_fail;
}
/* If the file is missing the kernel is too old, let's continue anyway. */
} else {
if (write(fd, "deny\n", 5) < 0) {
r = -errno;
goto child_fail;
}
fd = safe_close(fd);
}
/* First write the GID map */
a = procfs_file_alloca(ppid, "gid_map");
fd = open(a, O_WRONLY|O_CLOEXEC);
if (fd < 0) {
r = -errno;
goto child_fail;
}
if (write(fd, gid_map, strlen(gid_map)) < 0) {
r = -errno;
goto child_fail;
}
fd = safe_close(fd);
/* The write the UID map */
a = procfs_file_alloca(ppid, "uid_map");
fd = open(a, O_WRONLY|O_CLOEXEC);
if (fd < 0) {
r = -errno;
goto child_fail;
}
if (write(fd, uid_map, strlen(uid_map)) < 0) {
r = -errno;
goto child_fail;
}
_exit(EXIT_SUCCESS);
child_fail:
(void) write(errno_pipe[1], &r, sizeof(r));
_exit(EXIT_FAILURE);
}
errno_pipe[1] = safe_close(errno_pipe[1]);
if (unshare(CLONE_NEWUSER) < 0)
return -errno;
/* Let the child know that the namespace is ready now */
if (write(unshare_ready_fd, &c, sizeof(c)) < 0)
return -errno;
/* Try to read an error code from the child */
n = read(errno_pipe[0], &r, sizeof(r));
if (n < 0)
return -errno;
if (n == sizeof(r)) { /* an error code was sent to us */
if (r < 0)
return r;
return -EIO;
}
if (n != 0) /* on success we should have read 0 bytes */
return -EIO;
r = wait_for_terminate(pid, &si);
if (r < 0)
return r;
pid = 0;
/* If something strange happened with the child, let's consider this fatal, too */
if (si.si_code != CLD_EXITED || si.si_status != 0)
return -EIO;
return 0;
}
static int setup_runtime_directory(
const ExecContext *context,
const ExecParameters *params,
uid_t uid,
gid_t gid) {
char **rt;
int r;
assert(context);
assert(params);
STRV_FOREACH(rt, context->runtime_directory) {
_cleanup_free_ char *p;
p = strjoin(params->runtime_prefix, "/", *rt);
if (!p)
return -ENOMEM;
r = mkdir_p_label(p, context->runtime_directory_mode);
if (r < 0)
return r;
r = chmod_and_chown(p, context->runtime_directory_mode, uid, gid);
if (r < 0)
return r;
}
return 0;
}
static int setup_smack(
const ExecContext *context,
const ExecCommand *command) {
#ifdef HAVE_SMACK
int r;
assert(context);
assert(command);
if (!mac_smack_use())
return 0;
if (context->smack_process_label) {
r = mac_smack_apply_pid(0, context->smack_process_label);
if (r < 0)
return r;
}
#ifdef SMACK_DEFAULT_PROCESS_LABEL
else {
_cleanup_free_ char *exec_label = NULL;
r = mac_smack_read(command->path, SMACK_ATTR_EXEC, &exec_label);
if (r < 0 && r != -ENODATA && r != -EOPNOTSUPP)
return r;
r = mac_smack_apply_pid(0, exec_label ? : SMACK_DEFAULT_PROCESS_LABEL);
if (r < 0)
return r;
}
#endif
#endif
return 0;
}
static int compile_read_write_paths(
const ExecContext *context,
const ExecParameters *params,
char ***ret) {
_cleanup_strv_free_ char **l = NULL;
char **rt;
/* Compile the list of writable paths. This is the combination of the explicitly configured paths, plus all
* runtime directories. */
if (strv_isempty(context->read_write_paths) &&
strv_isempty(context->runtime_directory)) {
*ret = NULL; /* NOP if neither is set */
return 0;
}
l = strv_copy(context->read_write_paths);
if (!l)
return -ENOMEM;
STRV_FOREACH(rt, context->runtime_directory) {
char *s;
s = strjoin(params->runtime_prefix, "/", *rt);
if (!s)
return -ENOMEM;
if (strv_consume(&l, s) < 0)
return -ENOMEM;
}
*ret = l;
l = NULL;
return 0;
}
static int apply_mount_namespace(Unit *u, const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime) {
int r;
_cleanup_free_ char **rw = NULL;
char *tmp = NULL, *var = NULL;
const char *root_dir = NULL;
NameSpaceInfo ns_info = {
.ignore_protect_paths = false,
.private_dev = context->private_devices,
.protect_control_groups = context->protect_control_groups,
.protect_kernel_tunables = context->protect_kernel_tunables,
.protect_kernel_modules = context->protect_kernel_modules,
};
assert(context);
/* The runtime struct only contains the parent of the private /tmp,
* which is non-accessible to world users. Inside of it there's a /tmp
* that is sticky, and that's the one we want to use here. */
if (context->private_tmp && runtime) {
if (runtime->tmp_dir)
tmp = strjoina(runtime->tmp_dir, "/tmp");
if (runtime->var_tmp_dir)
var = strjoina(runtime->var_tmp_dir, "/tmp");
}
r = compile_read_write_paths(context, params, &rw);
if (r < 0)
return r;
if (params->flags & EXEC_APPLY_CHROOT)
root_dir = context->root_directory;
/*
* If DynamicUser=no and RootDirectory= is set then lets pass a relaxed
* sandbox info, otherwise enforce it, don't ignore protected paths and
* fail if we are enable to apply the sandbox inside the mount namespace.
*/
if (!context->dynamic_user && root_dir)
ns_info.ignore_protect_paths = true;
r = setup_namespace(root_dir, &ns_info, rw,
context->read_only_paths,
context->inaccessible_paths,
context->bind_mounts,
context->n_bind_mounts,
tmp,
var,
context->protect_home,
context->protect_system,
context->mount_flags);
/* If we couldn't set up the namespace this is probably due to a
* missing capability. In this case, silently proceeed. */
if (IN_SET(r, -EPERM, -EACCES)) {
log_open();
log_unit_debug_errno(u, r, "Failed to set up namespace, assuming containerized execution, ignoring: %m");
log_close();
r = 0;
}
return r;
}
static int apply_working_directory(const ExecContext *context,
const ExecParameters *params,
const char *home,
const bool needs_mount_ns) {
const char *d;
const char *wd;
assert(context);
if (context->working_directory_home)
wd = home;
else if (context->working_directory)
wd = context->working_directory;
else
wd = "/";
if (params->flags & EXEC_APPLY_CHROOT) {
if (!needs_mount_ns && context->root_directory)
if (chroot(context->root_directory) < 0)
return -errno;
d = wd;
} else
d = strjoina(strempty(context->root_directory), "/", strempty(wd));
if (chdir(d) < 0 && !context->working_directory_missing_ok)
return -errno;
return 0;
}
static int setup_keyring(Unit *u, const ExecParameters *p, uid_t uid, gid_t gid) {
key_serial_t keyring;
assert(u);
assert(p);
/* Let's set up a new per-service "session" kernel keyring for each system service. This has the benefit that
* each service runs with its own keyring shared among all processes of the service, but with no hook-up beyond
* that scope, and in particular no link to the per-UID keyring. If we don't do this the keyring will be
* automatically created on-demand and then linked to the per-UID keyring, by the kernel. The kernel's built-in
* on-demand behaviour is very appropriate for login users, but probably not so much for system services, where
* UIDs are not necessarily specific to a service but reused (at least in the case of UID 0). */
if (!(p->flags & EXEC_NEW_KEYRING))
return 0;
keyring = keyctl(KEYCTL_JOIN_SESSION_KEYRING, 0, 0, 0, 0);
if (keyring == -1) {
if (errno == ENOSYS)
log_debug_errno(errno, "Kernel keyring not supported, ignoring.");
else if (IN_SET(errno, EACCES, EPERM))
log_debug_errno(errno, "Kernel keyring access prohibited, ignoring.");
else if (errno == EDQUOT)
log_debug_errno(errno, "Out of kernel keyrings to allocate, ignoring.");
else
return log_error_errno(errno, "Setting up kernel keyring failed: %m");
return 0;
}
/* Populate they keyring with the invocation ID by default. */
if (!sd_id128_is_null(u->invocation_id)) {
key_serial_t key;
key = add_key("user", "invocation_id", &u->invocation_id, sizeof(u->invocation_id), KEY_SPEC_SESSION_KEYRING);
if (key == -1)
log_debug_errno(errno, "Failed to add invocation ID to keyring, ignoring: %m");
else {
if (keyctl(KEYCTL_SETPERM, key,
KEY_POS_VIEW|KEY_POS_READ|KEY_POS_SEARCH|
KEY_USR_VIEW|KEY_USR_READ|KEY_USR_SEARCH, 0, 0) < 0)
return log_error_errno(errno, "Failed to restrict invocation ID permission: %m");
}
}
/* And now, make the keyring owned by the service's user */
if (uid_is_valid(uid) || gid_is_valid(gid))
if (keyctl(KEYCTL_CHOWN, keyring, uid, gid, 0) < 0)
return log_error_errno(errno, "Failed to change ownership of session keyring: %m");
return 0;
}
static void append_socket_pair(int *array, unsigned *n, int pair[2]) {
assert(array);
assert(n);
if (!pair)
return;
if (pair[0] >= 0)
array[(*n)++] = pair[0];
if (pair[1] >= 0)
array[(*n)++] = pair[1];
}
static int close_remaining_fds(
const ExecParameters *params,
ExecRuntime *runtime,
DynamicCreds *dcreds,
int user_lookup_fd,
int socket_fd,
int *fds, unsigned n_fds) {
unsigned n_dont_close = 0;
int dont_close[n_fds + 12];
assert(params);
if (params->stdin_fd >= 0)
dont_close[n_dont_close++] = params->stdin_fd;
if (params->stdout_fd >= 0)
dont_close[n_dont_close++] = params->stdout_fd;
if (params->stderr_fd >= 0)
dont_close[n_dont_close++] = params->stderr_fd;
if (socket_fd >= 0)
dont_close[n_dont_close++] = socket_fd;
if (n_fds > 0) {
memcpy(dont_close + n_dont_close, fds, sizeof(int) * n_fds);
n_dont_close += n_fds;
}
if (runtime)
append_socket_pair(dont_close, &n_dont_close, runtime->netns_storage_socket);
if (dcreds) {
if (dcreds->user)
append_socket_pair(dont_close, &n_dont_close, dcreds->user->storage_socket);
if (dcreds->group)
append_socket_pair(dont_close, &n_dont_close, dcreds->group->storage_socket);
}
if (user_lookup_fd >= 0)
dont_close[n_dont_close++] = user_lookup_fd;
return close_all_fds(dont_close, n_dont_close);
}
static bool context_has_address_families(const ExecContext *c) {
assert(c);
return c->address_families_whitelist ||
!set_isempty(c->address_families);
}
static bool context_has_syscall_filters(const ExecContext *c) {
assert(c);
return c->syscall_whitelist ||
!set_isempty(c->syscall_filter) ||
!set_isempty(c->syscall_archs);
}
static bool context_has_no_new_privileges(const ExecContext *c) {
assert(c);
if (c->no_new_privileges)
return true;
if (have_effective_cap(CAP_SYS_ADMIN)) /* if we are privileged, we don't need NNP */
return false;
/* We need NNP if we have any form of seccomp and are unprivileged */
return context_has_address_families(c) ||
c->memory_deny_write_execute ||
c->restrict_realtime ||
exec_context_restrict_namespaces_set(c) ||
c->protect_kernel_tunables ||
c->protect_kernel_modules ||
c->private_devices ||
context_has_syscall_filters(c);
}
static int send_user_lookup(
Unit *unit,
int user_lookup_fd,
uid_t uid,
gid_t gid) {
assert(unit);
/* Send the resolved UID/GID to PID 1 after we learnt it. We send a single datagram, containing the UID/GID
* data as well as the unit name. Note that we suppress sending this if no user/group to resolve was
* specified. */
if (user_lookup_fd < 0)
return 0;
if (!uid_is_valid(uid) && !gid_is_valid(gid))
return 0;
if (writev(user_lookup_fd,
(struct iovec[]) {
{ .iov_base = &uid, .iov_len = sizeof(uid) },
{ .iov_base = &gid, .iov_len = sizeof(gid) },
{ .iov_base = unit->id, .iov_len = strlen(unit->id) }}, 3) < 0)
return -errno;
return 0;
}
static int exec_child(
Unit *unit,
ExecCommand *command,
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime,
DynamicCreds *dcreds,
char **argv,
int socket_fd,
int named_iofds[3],
int *fds, unsigned n_fds,
char **files_env,
int user_lookup_fd,
int *exit_status) {
_cleanup_strv_free_ char **our_env = NULL, **pass_env = NULL, **accum_env = NULL, **final_argv = NULL;
_cleanup_free_ char *mac_selinux_context_net = NULL;
_cleanup_free_ gid_t *supplementary_gids = NULL;
const char *username = NULL, *groupname = NULL;
const char *home = NULL, *shell = NULL;
dev_t journal_stream_dev = 0;
ino_t journal_stream_ino = 0;
bool needs_mount_namespace;
uid_t uid = UID_INVALID;
gid_t gid = GID_INVALID;
int i, r, ngids = 0;
assert(unit);
assert(command);
assert(context);
assert(params);
assert(exit_status);
rename_process_from_path(command->path);
/* We reset exactly these signals, since they are the
* only ones we set to SIG_IGN in the main daemon. All
* others we leave untouched because we set them to
* SIG_DFL or a valid handler initially, both of which
* will be demoted to SIG_DFL. */
(void) default_signals(SIGNALS_CRASH_HANDLER,
SIGNALS_IGNORE, -1);
if (context->ignore_sigpipe)
(void) ignore_signals(SIGPIPE, -1);
r = reset_signal_mask();
if (r < 0) {
*exit_status = EXIT_SIGNAL_MASK;
return r;
}
if (params->idle_pipe)
do_idle_pipe_dance(params->idle_pipe);
/* Close sockets very early to make sure we don't
* block init reexecution because it cannot bind its
* sockets */
log_forget_fds();
r = close_remaining_fds(params, runtime, dcreds, user_lookup_fd, socket_fd, fds, n_fds);
if (r < 0) {
*exit_status = EXIT_FDS;
return r;
}
if (!context->same_pgrp)
if (setsid() < 0) {
*exit_status = EXIT_SETSID;
return -errno;
}
exec_context_tty_reset(context, params);
if (unit_shall_confirm_spawn(unit)) {
const char *vc = params->confirm_spawn;
_cleanup_free_ char *cmdline = NULL;
cmdline = exec_command_line(argv);
if (!cmdline) {
*exit_status = EXIT_CONFIRM;
return -ENOMEM;
}
r = ask_for_confirmation(vc, unit, cmdline);
if (r != CONFIRM_EXECUTE) {
if (r == CONFIRM_PRETEND_SUCCESS) {
*exit_status = EXIT_SUCCESS;
return 0;
}
*exit_status = EXIT_CONFIRM;
return -ECANCELED;
}
}
if (context->dynamic_user && dcreds) {
/* Make sure we bypass our own NSS module for any NSS checks */
if (putenv((char*) "SYSTEMD_NSS_DYNAMIC_BYPASS=1") != 0) {
*exit_status = EXIT_USER;
return -errno;
}
r = dynamic_creds_realize(dcreds, &uid, &gid);
if (r < 0) {
*exit_status = EXIT_USER;
return r;
}
if (!uid_is_valid(uid) || !gid_is_valid(gid)) {
*exit_status = EXIT_USER;
return -ESRCH;
}
if (dcreds->user)
username = dcreds->user->name;
} else {
r = get_fixed_user(context, &username, &uid, &gid, &home, &shell);
if (r < 0) {
*exit_status = EXIT_USER;
return r;
}
r = get_fixed_group(context, &groupname, &gid);
if (r < 0) {
*exit_status = EXIT_GROUP;
return r;
}
}
/* Initialize user supplementary groups and get SupplementaryGroups= ones */
r = get_supplementary_groups(context, username, groupname, gid,
&supplementary_gids, &ngids);
if (r < 0) {
*exit_status = EXIT_GROUP;
return r;
}
r = send_user_lookup(unit, user_lookup_fd, uid, gid);
if (r < 0) {
*exit_status = EXIT_USER;
return r;
}
user_lookup_fd = safe_close(user_lookup_fd);
/* If a socket is connected to STDIN/STDOUT/STDERR, we
* must sure to drop O_NONBLOCK */
if (socket_fd >= 0)
(void) fd_nonblock(socket_fd, false);
r = setup_input(context, params, socket_fd, named_iofds);
if (r < 0) {
*exit_status = EXIT_STDIN;
return r;
}
r = setup_output(unit, context, params, STDOUT_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino);
if (r < 0) {
*exit_status = EXIT_STDOUT;
return r;
}
r = setup_output(unit, context, params, STDERR_FILENO, socket_fd, named_iofds, basename(command->path), uid, gid, &journal_stream_dev, &journal_stream_ino);
if (r < 0) {
*exit_status = EXIT_STDERR;
return r;
}
if (params->cgroup_path) {
r = cg_attach_everywhere(params->cgroup_supported, params->cgroup_path, 0, NULL, NULL);
if (r < 0) {
*exit_status = EXIT_CGROUP;
return r;
}
}
if (context->oom_score_adjust_set) {
char t[DECIMAL_STR_MAX(context->oom_score_adjust)];
/* When we can't make this change due to EPERM, then
* let's silently skip over it. User namespaces
* prohibit write access to this file, and we
* shouldn't trip up over that. */
sprintf(t, "%i", context->oom_score_adjust);
r = write_string_file("/proc/self/oom_score_adj", t, 0);
if (r == -EPERM || r == -EACCES) {
log_open();
log_unit_debug_errno(unit, r, "Failed to adjust OOM setting, assuming containerized execution, ignoring: %m");
log_close();
} else if (r < 0) {
*exit_status = EXIT_OOM_ADJUST;
return -errno;
}
}
if (context->nice_set)
if (setpriority(PRIO_PROCESS, 0, context->nice) < 0) {
*exit_status = EXIT_NICE;
return -errno;
}
if (context->cpu_sched_set) {
struct sched_param param = {
.sched_priority = context->cpu_sched_priority,
};
r = sched_setscheduler(0,
context->cpu_sched_policy |
(context->cpu_sched_reset_on_fork ?
SCHED_RESET_ON_FORK : 0),
&param);
if (r < 0) {
*exit_status = EXIT_SETSCHEDULER;
return -errno;
}
}
if (context->cpuset)
if (sched_setaffinity(0, CPU_ALLOC_SIZE(context->cpuset_ncpus), context->cpuset) < 0) {
*exit_status = EXIT_CPUAFFINITY;
return -errno;
}
if (context->ioprio_set)
if (ioprio_set(IOPRIO_WHO_PROCESS, 0, context->ioprio) < 0) {
*exit_status = EXIT_IOPRIO;
return -errno;
}
if (context->timer_slack_nsec != NSEC_INFINITY)
if (prctl(PR_SET_TIMERSLACK, context->timer_slack_nsec) < 0) {
*exit_status = EXIT_TIMERSLACK;
return -errno;
}
if (context->personality != PERSONALITY_INVALID)
if (personality(context->personality) < 0) {
*exit_status = EXIT_PERSONALITY;
return -errno;
}
if (context->utmp_id)
utmp_put_init_process(context->utmp_id, getpid(), getsid(0), context->tty_path,
context->utmp_mode == EXEC_UTMP_INIT ? INIT_PROCESS :
context->utmp_mode == EXEC_UTMP_LOGIN ? LOGIN_PROCESS :
USER_PROCESS,
username ? "root" : context->user);
if (context->user) {
r = chown_terminal(STDIN_FILENO, uid);
if (r < 0) {
*exit_status = EXIT_STDIN;
return r;
}
}
/* If delegation is enabled we'll pass ownership of the cgroup
* (but only in systemd's own controller hierarchy!) to the
* user of the new process. */
if (params->cgroup_path && context->user && params->cgroup_delegate) {
r = cg_set_task_access(SYSTEMD_CGROUP_CONTROLLER, params->cgroup_path, 0644, uid, gid);
if (r < 0) {
*exit_status = EXIT_CGROUP;
return r;
}
r = cg_set_group_access(SYSTEMD_CGROUP_CONTROLLER, params->cgroup_path, 0755, uid, gid);
if (r < 0) {
*exit_status = EXIT_CGROUP;
return r;
}
}
if (!strv_isempty(context->runtime_directory) && params->runtime_prefix) {
r = setup_runtime_directory(context, params, uid, gid);
if (r < 0) {
*exit_status = EXIT_RUNTIME_DIRECTORY;
return r;
}
}
r = build_environment(
unit,
context,
params,
n_fds,
home,
username,
shell,
journal_stream_dev,
journal_stream_ino,
&our_env);
if (r < 0) {
*exit_status = EXIT_MEMORY;
return r;
}
r = build_pass_environment(context, &pass_env);
if (r < 0) {
*exit_status = EXIT_MEMORY;
return r;
}
accum_env = strv_env_merge(5,
params->environment,
our_env,
pass_env,
context->environment,
files_env,
NULL);
if (!accum_env) {
*exit_status = EXIT_MEMORY;
return -ENOMEM;
}
accum_env = strv_env_clean(accum_env);
(void) umask(context->umask);
r = setup_keyring(unit, params, uid, gid);
if (r < 0) {
*exit_status = EXIT_KEYRING;
return r;
}
if ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
if (context->pam_name && username) {
r = setup_pam(context->pam_name, username, uid, gid, context->tty_path, &accum_env, fds, n_fds);
if (r < 0) {
*exit_status = EXIT_PAM;
return r;
}
}
}
if (context->private_network && runtime && runtime->netns_storage_socket[0] >= 0) {
r = setup_netns(runtime->netns_storage_socket);
if (r < 0) {
*exit_status = EXIT_NETWORK;
return r;
}
}
needs_mount_namespace = exec_needs_mount_namespace(context, params, runtime);
if (needs_mount_namespace) {
r = apply_mount_namespace(unit, context, params, runtime);
if (r < 0) {
*exit_status = EXIT_NAMESPACE;
return r;
}
}
/* Apply just after mount namespace setup */
r = apply_working_directory(context, params, home, needs_mount_namespace);
if (r < 0) {
*exit_status = EXIT_CHROOT;
return r;
}
/* Drop groups as early as possbile */
if ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
r = enforce_groups(context, gid, supplementary_gids, ngids);
if (r < 0) {
*exit_status = EXIT_GROUP;
return r;
}
}
#ifdef HAVE_SELINUX
if ((params->flags & EXEC_APPLY_PERMISSIONS) &&
mac_selinux_use() &&
params->selinux_context_net &&
socket_fd >= 0 &&
!command->privileged) {
r = mac_selinux_get_child_mls_label(socket_fd, command->path, context->selinux_context, &mac_selinux_context_net);
if (r < 0) {
*exit_status = EXIT_SELINUX_CONTEXT;
return r;
}
}
#endif
if ((params->flags & EXEC_APPLY_PERMISSIONS) && context->private_users) {
r = setup_private_users(uid, gid);
if (r < 0) {
*exit_status = EXIT_USER;
return r;
}
}
/* We repeat the fd closing here, to make sure that
* nothing is leaked from the PAM modules. Note that
* we are more aggressive this time since socket_fd
* and the netns fds we don't need anymore. The custom
* endpoint fd was needed to upload the policy and can
* now be closed as well. */
r = close_all_fds(fds, n_fds);
if (r >= 0)
r = shift_fds(fds, n_fds);
if (r >= 0)
r = flags_fds(fds, n_fds, context->non_blocking);
if (r < 0) {
*exit_status = EXIT_FDS;
return r;
}
if ((params->flags & EXEC_APPLY_PERMISSIONS) && !command->privileged) {
int secure_bits = context->secure_bits;
for (i = 0; i < _RLIMIT_MAX; i++) {
if (!context->rlimit[i])
continue;
r = setrlimit_closest(i, context->rlimit[i]);
if (r < 0) {
*exit_status = EXIT_LIMITS;
return r;
}
}
/* Set the RTPRIO resource limit to 0, but only if nothing else was explicitly requested. */
if (context->restrict_realtime && !context->rlimit[RLIMIT_RTPRIO]) {
if (setrlimit(RLIMIT_RTPRIO, &RLIMIT_MAKE_CONST(0)) < 0) {
*exit_status = EXIT_LIMITS;
return -errno;
}
}
if (!cap_test_all(context->capability_bounding_set)) {
r = capability_bounding_set_drop(context->capability_bounding_set, false);
if (r < 0) {
*exit_status = EXIT_CAPABILITIES;
return r;
}
}
/* This is done before enforce_user, but ambient set
* does not survive over setresuid() if keep_caps is not set. */
if (context->capability_ambient_set != 0) {
r = capability_ambient_set_apply(context->capability_ambient_set, true);
if (r < 0) {
*exit_status = EXIT_CAPABILITIES;
return r;
}
}
if (context->user) {
r = enforce_user(context, uid);
if (r < 0) {
*exit_status = EXIT_USER;
return r;
}
if (context->capability_ambient_set != 0) {
/* Fix the ambient capabilities after user change. */
r = capability_ambient_set_apply(context->capability_ambient_set, false);
if (r < 0) {
*exit_status = EXIT_CAPABILITIES;
return r;
}
/* If we were asked to change user and ambient capabilities
* were requested, we had to add keep-caps to the securebits
* so that we would maintain the inherited capability set
* through the setresuid(). Make sure that the bit is added
* also to the context secure_bits so that we don't try to
* drop the bit away next. */
secure_bits |= 1<<SECURE_KEEP_CAPS;
}
}
/* Apply the MAC contexts late, but before seccomp syscall filtering, as those should really be last to
* influence our own codepaths as little as possible. Moreover, applying MAC contexts usually requires
* syscalls that are subject to seccomp filtering, hence should probably be applied before the syscalls
* are restricted. */
#ifdef HAVE_SELINUX
if (mac_selinux_use()) {
char *exec_context = mac_selinux_context_net ?: context->selinux_context;
if (exec_context) {
r = setexeccon(exec_context);
if (r < 0) {
*exit_status = EXIT_SELINUX_CONTEXT;
return r;
}
}
}
#endif
r = setup_smack(context, command);
if (r < 0) {
*exit_status = EXIT_SMACK_PROCESS_LABEL;
return r;
}
#ifdef HAVE_APPARMOR
if (context->apparmor_profile && mac_apparmor_use()) {
r = aa_change_onexec(context->apparmor_profile);
if (r < 0 && !context->apparmor_profile_ignore) {
*exit_status = EXIT_APPARMOR_PROFILE;
return -errno;
}
}
#endif
/* PR_GET_SECUREBITS is not privileged, while
* PR_SET_SECUREBITS is. So to suppress
* potential EPERMs we'll try not to call
* PR_SET_SECUREBITS unless necessary. */
if (prctl(PR_GET_SECUREBITS) != secure_bits)
if (prctl(PR_SET_SECUREBITS, secure_bits) < 0) {
*exit_status = EXIT_SECUREBITS;
return -errno;
}
if (context_has_no_new_privileges(context))
if (prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0) < 0) {
*exit_status = EXIT_NO_NEW_PRIVILEGES;
return -errno;
}
#ifdef HAVE_SECCOMP
if (context_has_address_families(context)) {
r = apply_address_families(unit, context);
if (r < 0) {
*exit_status = EXIT_ADDRESS_FAMILIES;
return r;
}
}
if (context->memory_deny_write_execute) {
r = apply_memory_deny_write_execute(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
}
}
if (context->restrict_realtime) {
r = apply_restrict_realtime(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
}
}
r = apply_restrict_namespaces(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
}
if (context->protect_kernel_tunables) {
r = apply_protect_sysctl(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
}
}
if (context->protect_kernel_modules) {
r = apply_protect_kernel_modules(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
}
}
if (context->private_devices) {
r = apply_private_devices(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
}
}
/* This really should remain the last step before the execve(), to make sure our own code is unaffected
* by the filter as little as possible. */
if (context_has_syscall_filters(context)) {
r = apply_seccomp(unit, context);
if (r < 0) {
*exit_status = EXIT_SECCOMP;
return r;
}
}
#endif
}
final_argv = replace_env_argv(argv, accum_env);
if (!final_argv) {
*exit_status = EXIT_MEMORY;
return -ENOMEM;
}
if (_unlikely_(log_get_max_level() >= LOG_DEBUG)) {
_cleanup_free_ char *line;
line = exec_command_line(final_argv);
if (line) {
log_open();
log_struct(LOG_DEBUG,
LOG_UNIT_ID(unit),
"EXECUTABLE=%s", command->path,
LOG_UNIT_MESSAGE(unit, "Executing: %s", line),
NULL);
log_close();
}
}
execve(command->path, final_argv, accum_env);
*exit_status = EXIT_EXEC;
return -errno;
}
int exec_spawn(Unit *unit,
ExecCommand *command,
const ExecContext *context,
const ExecParameters *params,
ExecRuntime *runtime,
DynamicCreds *dcreds,
pid_t *ret) {
_cleanup_strv_free_ char **files_env = NULL;
int *fds = NULL; unsigned n_fds = 0;
_cleanup_free_ char *line = NULL;
int socket_fd, r;
int named_iofds[3] = { -1, -1, -1 };
char **argv;
pid_t pid;
assert(unit);
assert(command);
assert(context);
assert(ret);
assert(params);
assert(params->fds || params->n_fds <= 0);
if (context->std_input == EXEC_INPUT_SOCKET ||
context->std_output == EXEC_OUTPUT_SOCKET ||
context->std_error == EXEC_OUTPUT_SOCKET) {
if (params->n_fds != 1) {
log_unit_error(unit, "Got more than one socket.");
return -EINVAL;
}
socket_fd = params->fds[0];
} else {
socket_fd = -1;
fds = params->fds;
n_fds = params->n_fds;
}
r = exec_context_named_iofds(unit, context, params, named_iofds);
if (r < 0)
return log_unit_error_errno(unit, r, "Failed to load a named file descriptor: %m");
r = exec_context_load_environment(unit, context, &files_env);
if (r < 0)
return log_unit_error_errno(unit, r, "Failed to load environment files: %m");
argv = params->argv ?: command->argv;
line = exec_command_line(argv);
if (!line)
return log_oom();
log_struct(LOG_DEBUG,
LOG_UNIT_ID(unit),
LOG_UNIT_MESSAGE(unit, "About to execute: %s", line),
"EXECUTABLE=%s", command->path,
NULL);
pid = fork();
if (pid < 0)
return log_unit_error_errno(unit, errno, "Failed to fork: %m");
if (pid == 0) {
int exit_status;
r = exec_child(unit,
command,
context,
params,
runtime,
dcreds,
argv,
socket_fd,
named_iofds,
fds, n_fds,
files_env,
unit->manager->user_lookup_fds[1],
&exit_status);
if (r < 0) {
log_open();
log_struct_errno(LOG_ERR, r,
LOG_MESSAGE_ID(SD_MESSAGE_SPAWN_FAILED),
LOG_UNIT_ID(unit),
LOG_UNIT_MESSAGE(unit, "Failed at step %s spawning %s: %m",
exit_status_to_string(exit_status, EXIT_STATUS_SYSTEMD),
command->path),
"EXECUTABLE=%s", command->path,
NULL);
}
_exit(exit_status);
}
log_unit_debug(unit, "Forked %s as "PID_FMT, command->path, pid);
/* We add the new process to the cgroup both in the child (so
* that we can be sure that no user code is ever executed
* outside of the cgroup) and in the parent (so that we can be
* sure that when we kill the cgroup the process will be
* killed too). */
if (params->cgroup_path)
(void) cg_attach(SYSTEMD_CGROUP_CONTROLLER, params->cgroup_path, pid);
exec_status_start(&command->exec_status, pid);
*ret = pid;
return 0;
}
void exec_context_init(ExecContext *c) {
assert(c);
c->umask = 0022;
c->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 0);
c->cpu_sched_policy = SCHED_OTHER;
c->syslog_priority = LOG_DAEMON|LOG_INFO;
c->syslog_level_prefix = true;
c->ignore_sigpipe = true;
c->timer_slack_nsec = NSEC_INFINITY;
c->personality = PERSONALITY_INVALID;
c->runtime_directory_mode = 0755;
c->capability_bounding_set = CAP_ALL;
c->restrict_namespaces = NAMESPACE_FLAGS_ALL;
}
void exec_context_done(ExecContext *c) {
unsigned l;
assert(c);
c->environment = strv_free(c->environment);
c->environment_files = strv_free(c->environment_files);
c->pass_environment = strv_free(c->pass_environment);
for (l = 0; l < ELEMENTSOF(c->rlimit); l++)
c->rlimit[l] = mfree(c->rlimit[l]);
for (l = 0; l < 3; l++)
c->stdio_fdname[l] = mfree(c->stdio_fdname[l]);
c->working_directory = mfree(c->working_directory);
c->root_directory = mfree(c->root_directory);
c->tty_path = mfree(c->tty_path);
c->syslog_identifier = mfree(c->syslog_identifier);
c->user = mfree(c->user);
c->group = mfree(c->group);
c->supplementary_groups = strv_free(c->supplementary_groups);
c->pam_name = mfree(c->pam_name);
c->read_only_paths = strv_free(c->read_only_paths);
c->read_write_paths = strv_free(c->read_write_paths);
c->inaccessible_paths = strv_free(c->inaccessible_paths);
bind_mount_free_many(c->bind_mounts, c->n_bind_mounts);
if (c->cpuset)
CPU_FREE(c->cpuset);
c->utmp_id = mfree(c->utmp_id);
c->selinux_context = mfree(c->selinux_context);
c->apparmor_profile = mfree(c->apparmor_profile);
c->syscall_filter = set_free(c->syscall_filter);
c->syscall_archs = set_free(c->syscall_archs);
c->address_families = set_free(c->address_families);
c->runtime_directory = strv_free(c->runtime_directory);
}
int exec_context_destroy_runtime_directory(ExecContext *c, const char *runtime_prefix) {
char **i;
assert(c);
if (!runtime_prefix)
return 0;
STRV_FOREACH(i, c->runtime_directory) {
_cleanup_free_ char *p;
p = strjoin(runtime_prefix, "/", *i);
if (!p)
return -ENOMEM;
/* We execute this synchronously, since we need to be
* sure this is gone when we start the service
* next. */
(void) rm_rf(p, REMOVE_ROOT);
}
return 0;
}
void exec_command_done(ExecCommand *c) {
assert(c);
c->path = mfree(c->path);
c->argv = strv_free(c->argv);
}
void exec_command_done_array(ExecCommand *c, unsigned n) {
unsigned i;
for (i = 0; i < n; i++)
exec_command_done(c+i);
}
ExecCommand* exec_command_free_list(ExecCommand *c) {
ExecCommand *i;
while ((i = c)) {
LIST_REMOVE(command, c, i);
exec_command_done(i);
free(i);
}
return NULL;
}
void exec_command_free_array(ExecCommand **c, unsigned n) {
unsigned i;
for (i = 0; i < n; i++)
c[i] = exec_command_free_list(c[i]);
}
typedef struct InvalidEnvInfo {
Unit *unit;
const char *path;
} InvalidEnvInfo;
static void invalid_env(const char *p, void *userdata) {
InvalidEnvInfo *info = userdata;
log_unit_error(info->unit, "Ignoring invalid environment assignment '%s': %s", p, info->path);
}
const char* exec_context_fdname(const ExecContext *c, int fd_index) {
assert(c);
switch (fd_index) {
case STDIN_FILENO:
if (c->std_input != EXEC_INPUT_NAMED_FD)
return NULL;
return c->stdio_fdname[STDIN_FILENO] ?: "stdin";
case STDOUT_FILENO:
if (c->std_output != EXEC_OUTPUT_NAMED_FD)
return NULL;
return c->stdio_fdname[STDOUT_FILENO] ?: "stdout";
case STDERR_FILENO:
if (c->std_error != EXEC_OUTPUT_NAMED_FD)
return NULL;
return c->stdio_fdname[STDERR_FILENO] ?: "stderr";
default:
return NULL;
}
}
int exec_context_named_iofds(Unit *unit, const ExecContext *c, const ExecParameters *p, int named_iofds[3]) {
unsigned i, targets;
const char *stdio_fdname[3];
assert(c);
assert(p);
targets = (c->std_input == EXEC_INPUT_NAMED_FD) +
(c->std_output == EXEC_OUTPUT_NAMED_FD) +
(c->std_error == EXEC_OUTPUT_NAMED_FD);
for (i = 0; i < 3; i++)
stdio_fdname[i] = exec_context_fdname(c, i);
for (i = 0; i < p->n_fds && targets > 0; i++)
if (named_iofds[STDIN_FILENO] < 0 && c->std_input == EXEC_INPUT_NAMED_FD && stdio_fdname[STDIN_FILENO] && streq(p->fd_names[i], stdio_fdname[STDIN_FILENO])) {
named_iofds[STDIN_FILENO] = p->fds[i];
targets--;
} else if (named_iofds[STDOUT_FILENO] < 0 && c->std_output == EXEC_OUTPUT_NAMED_FD && stdio_fdname[STDOUT_FILENO] && streq(p->fd_names[i], stdio_fdname[STDOUT_FILENO])) {
named_iofds[STDOUT_FILENO] = p->fds[i];
targets--;
} else if (named_iofds[STDERR_FILENO] < 0 && c->std_error == EXEC_OUTPUT_NAMED_FD && stdio_fdname[STDERR_FILENO] && streq(p->fd_names[i], stdio_fdname[STDERR_FILENO])) {
named_iofds[STDERR_FILENO] = p->fds[i];
targets--;
}
return (targets == 0 ? 0 : -ENOENT);
}
int exec_context_load_environment(Unit *unit, const ExecContext *c, char ***l) {
char **i, **r = NULL;
assert(c);
assert(l);
STRV_FOREACH(i, c->environment_files) {
char *fn;
int k;
bool ignore = false;
char **p;
_cleanup_globfree_ glob_t pglob = {};
int count, n;
fn = *i;
if (fn[0] == '-') {
ignore = true;
fn++;
}
if (!path_is_absolute(fn)) {
if (ignore)
continue;
strv_free(r);
return -EINVAL;
}
/* Filename supports globbing, take all matching files */
errno = 0;
if (glob(fn, 0, NULL, &pglob) != 0) {
if (ignore)
continue;
strv_free(r);
return errno > 0 ? -errno : -EINVAL;
}
count = pglob.gl_pathc;
if (count == 0) {
if (ignore)
continue;
strv_free(r);
return -EINVAL;
}
for (n = 0; n < count; n++) {
k = load_env_file(NULL, pglob.gl_pathv[n], NULL, &p);
if (k < 0) {
if (ignore)
continue;
strv_free(r);
return k;
}
/* Log invalid environment variables with filename */
if (p) {
InvalidEnvInfo info = {
.unit = unit,
.path = pglob.gl_pathv[n]
};
p = strv_env_clean_with_callback(p, invalid_env, &info);
}
if (r == NULL)
r = p;
else {
char **m;
m = strv_env_merge(2, r, p);
strv_free(r);
strv_free(p);
if (!m)
return -ENOMEM;
r = m;
}
}
}
*l = r;
return 0;
}
static bool tty_may_match_dev_console(const char *tty) {
_cleanup_free_ char *active = NULL;
char *console;
if (!tty)
return true;
if (startswith(tty, "/dev/"))
tty += 5;
/* trivial identity? */
if (streq(tty, "console"))
return true;
console = resolve_dev_console(&active);
/* if we could not resolve, assume it may */
if (!console)
return true;
/* "tty0" means the active VC, so it may be the same sometimes */
return streq(console, tty) || (streq(console, "tty0") && tty_is_vc(tty));
}
bool exec_context_may_touch_console(ExecContext *ec) {
return (ec->tty_reset ||
ec->tty_vhangup ||
ec->tty_vt_disallocate ||
is_terminal_input(ec->std_input) ||
is_terminal_output(ec->std_output) ||
is_terminal_output(ec->std_error)) &&
tty_may_match_dev_console(exec_context_tty_path(ec));
}
static void strv_fprintf(FILE *f, char **l) {
char **g;
assert(f);
STRV_FOREACH(g, l)
fprintf(f, " %s", *g);
}
void exec_context_dump(ExecContext *c, FILE* f, const char *prefix) {
char **e, **d;
unsigned i;
int r;
assert(c);
assert(f);
prefix = strempty(prefix);
fprintf(f,
"%sUMask: %04o\n"
"%sWorkingDirectory: %s\n"
"%sRootDirectory: %s\n"
"%sNonBlocking: %s\n"
"%sPrivateTmp: %s\n"
"%sPrivateDevices: %s\n"
"%sProtectKernelTunables: %s\n"
"%sProtectKernelModules: %s\n"
"%sProtectControlGroups: %s\n"
"%sPrivateNetwork: %s\n"
"%sPrivateUsers: %s\n"
"%sProtectHome: %s\n"
"%sProtectSystem: %s\n"
"%sIgnoreSIGPIPE: %s\n"
"%sMemoryDenyWriteExecute: %s\n"
"%sRestrictRealtime: %s\n",
prefix, c->umask,
prefix, c->working_directory ? c->working_directory : "/",
prefix, c->root_directory ? c->root_directory : "/",
prefix, yes_no(c->non_blocking),
prefix, yes_no(c->private_tmp),
prefix, yes_no(c->private_devices),
prefix, yes_no(c->protect_kernel_tunables),
prefix, yes_no(c->protect_kernel_modules),
prefix, yes_no(c->protect_control_groups),
prefix, yes_no(c->private_network),
prefix, yes_no(c->private_users),
prefix, protect_home_to_string(c->protect_home),
prefix, protect_system_to_string(c->protect_system),
prefix, yes_no(c->ignore_sigpipe),
prefix, yes_no(c->memory_deny_write_execute),
prefix, yes_no(c->restrict_realtime));
STRV_FOREACH(e, c->environment)
fprintf(f, "%sEnvironment: %s\n", prefix, *e);
STRV_FOREACH(e, c->environment_files)
fprintf(f, "%sEnvironmentFile: %s\n", prefix, *e);
STRV_FOREACH(e, c->pass_environment)
fprintf(f, "%sPassEnvironment: %s\n", prefix, *e);
fprintf(f, "%sRuntimeDirectoryMode: %04o\n", prefix, c->runtime_directory_mode);
STRV_FOREACH(d, c->runtime_directory)
fprintf(f, "%sRuntimeDirectory: %s\n", prefix, *d);
if (c->nice_set)
fprintf(f,
"%sNice: %i\n",
prefix, c->nice);
if (c->oom_score_adjust_set)
fprintf(f,
"%sOOMScoreAdjust: %i\n",
prefix, c->oom_score_adjust);
for (i = 0; i < RLIM_NLIMITS; i++)
if (c->rlimit[i]) {
fprintf(f, "%s%s: " RLIM_FMT "\n",
prefix, rlimit_to_string(i), c->rlimit[i]->rlim_max);
fprintf(f, "%s%sSoft: " RLIM_FMT "\n",
prefix, rlimit_to_string(i), c->rlimit[i]->rlim_cur);
}
if (c->ioprio_set) {
_cleanup_free_ char *class_str = NULL;
ioprio_class_to_string_alloc(IOPRIO_PRIO_CLASS(c->ioprio), &class_str);
fprintf(f,
"%sIOSchedulingClass: %s\n"
"%sIOPriority: %i\n",
prefix, strna(class_str),
prefix, (int) IOPRIO_PRIO_DATA(c->ioprio));
}
if (c->cpu_sched_set) {
_cleanup_free_ char *policy_str = NULL;
sched_policy_to_string_alloc(c->cpu_sched_policy, &policy_str);
fprintf(f,
"%sCPUSchedulingPolicy: %s\n"
"%sCPUSchedulingPriority: %i\n"
"%sCPUSchedulingResetOnFork: %s\n",
prefix, strna(policy_str),
prefix, c->cpu_sched_priority,
prefix, yes_no(c->cpu_sched_reset_on_fork));
}
if (c->cpuset) {
fprintf(f, "%sCPUAffinity:", prefix);
for (i = 0; i < c->cpuset_ncpus; i++)
if (CPU_ISSET_S(i, CPU_ALLOC_SIZE(c->cpuset_ncpus), c->cpuset))
fprintf(f, " %u", i);
fputs("\n", f);
}
if (c->timer_slack_nsec != NSEC_INFINITY)
fprintf(f, "%sTimerSlackNSec: "NSEC_FMT "\n", prefix, c->timer_slack_nsec);
fprintf(f,
"%sStandardInput: %s\n"
"%sStandardOutput: %s\n"
"%sStandardError: %s\n",
prefix, exec_input_to_string(c->std_input),
prefix, exec_output_to_string(c->std_output),
prefix, exec_output_to_string(c->std_error));
if (c->tty_path)
fprintf(f,
"%sTTYPath: %s\n"
"%sTTYReset: %s\n"
"%sTTYVHangup: %s\n"
"%sTTYVTDisallocate: %s\n",
prefix, c->tty_path,
prefix, yes_no(c->tty_reset),
prefix, yes_no(c->tty_vhangup),
prefix, yes_no(c->tty_vt_disallocate));
if (c->std_output == EXEC_OUTPUT_SYSLOG ||
c->std_output == EXEC_OUTPUT_KMSG ||
c->std_output == EXEC_OUTPUT_JOURNAL ||
c->std_output == EXEC_OUTPUT_SYSLOG_AND_CONSOLE ||
c->std_output == EXEC_OUTPUT_KMSG_AND_CONSOLE ||
c->std_output == EXEC_OUTPUT_JOURNAL_AND_CONSOLE ||
c->std_error == EXEC_OUTPUT_SYSLOG ||
c->std_error == EXEC_OUTPUT_KMSG ||
c->std_error == EXEC_OUTPUT_JOURNAL ||
c->std_error == EXEC_OUTPUT_SYSLOG_AND_CONSOLE ||
c->std_error == EXEC_OUTPUT_KMSG_AND_CONSOLE ||
c->std_error == EXEC_OUTPUT_JOURNAL_AND_CONSOLE) {
_cleanup_free_ char *fac_str = NULL, *lvl_str = NULL;
log_facility_unshifted_to_string_alloc(c->syslog_priority >> 3, &fac_str);
log_level_to_string_alloc(LOG_PRI(c->syslog_priority), &lvl_str);
fprintf(f,
"%sSyslogFacility: %s\n"
"%sSyslogLevel: %s\n",
prefix, strna(fac_str),
prefix, strna(lvl_str));
}
if (c->secure_bits)
fprintf(f, "%sSecure Bits:%s%s%s%s%s%s\n",
prefix,
(c->secure_bits & 1<<SECURE_KEEP_CAPS) ? " keep-caps" : "",
(c->secure_bits & 1<<SECURE_KEEP_CAPS_LOCKED) ? " keep-caps-locked" : "",
(c->secure_bits & 1<<SECURE_NO_SETUID_FIXUP) ? " no-setuid-fixup" : "",
(c->secure_bits & 1<<SECURE_NO_SETUID_FIXUP_LOCKED) ? " no-setuid-fixup-locked" : "",
(c->secure_bits & 1<<SECURE_NOROOT) ? " noroot" : "",
(c->secure_bits & 1<<SECURE_NOROOT_LOCKED) ? "noroot-locked" : "");
if (c->capability_bounding_set != CAP_ALL) {
unsigned long l;
fprintf(f, "%sCapabilityBoundingSet:", prefix);
for (l = 0; l <= cap_last_cap(); l++)
if (c->capability_bounding_set & (UINT64_C(1) << l))
fprintf(f, " %s", strna(capability_to_name(l)));
fputs("\n", f);
}
if (c->capability_ambient_set != 0) {
unsigned long l;
fprintf(f, "%sAmbientCapabilities:", prefix);
for (l = 0; l <= cap_last_cap(); l++)
if (c->capability_ambient_set & (UINT64_C(1) << l))
fprintf(f, " %s", strna(capability_to_name(l)));
fputs("\n", f);
}
if (c->user)
fprintf(f, "%sUser: %s\n", prefix, c->user);
if (c->group)
fprintf(f, "%sGroup: %s\n", prefix, c->group);
fprintf(f, "%sDynamicUser: %s\n", prefix, yes_no(c->dynamic_user));
if (strv_length(c->supplementary_groups) > 0) {
fprintf(f, "%sSupplementaryGroups:", prefix);
strv_fprintf(f, c->supplementary_groups);
fputs("\n", f);
}
if (c->pam_name)
fprintf(f, "%sPAMName: %s\n", prefix, c->pam_name);
if (strv_length(c->read_write_paths) > 0) {
fprintf(f, "%sReadWritePaths:", prefix);
strv_fprintf(f, c->read_write_paths);
fputs("\n", f);
}
if (strv_length(c->read_only_paths) > 0) {
fprintf(f, "%sReadOnlyPaths:", prefix);
strv_fprintf(f, c->read_only_paths);
fputs("\n", f);
}
if (strv_length(c->inaccessible_paths) > 0) {
fprintf(f, "%sInaccessiblePaths:", prefix);
strv_fprintf(f, c->inaccessible_paths);
fputs("\n", f);
}
if (c->n_bind_mounts > 0)
for (i = 0; i < c->n_bind_mounts; i++) {
fprintf(f, "%s%s: %s:%s:%s\n", prefix,
c->bind_mounts[i].read_only ? "BindReadOnlyPaths" : "BindPaths",
c->bind_mounts[i].source,
c->bind_mounts[i].destination,
c->bind_mounts[i].recursive ? "rbind" : "norbind");
}
if (c->utmp_id)
fprintf(f,
"%sUtmpIdentifier: %s\n",
prefix, c->utmp_id);
if (c->selinux_context)
fprintf(f,
"%sSELinuxContext: %s%s\n",
prefix, c->selinux_context_ignore ? "-" : "", c->selinux_context);
if (c->personality != PERSONALITY_INVALID)
fprintf(f,
"%sPersonality: %s\n",
prefix, strna(personality_to_string(c->personality)));
if (c->syscall_filter) {
#ifdef HAVE_SECCOMP
Iterator j;
void *id;
bool first = true;
#endif
fprintf(f,
"%sSystemCallFilter: ",
prefix);
if (!c->syscall_whitelist)
fputc('~', f);
#ifdef HAVE_SECCOMP
SET_FOREACH(id, c->syscall_filter, j) {
_cleanup_free_ char *name = NULL;
if (first)
first = false;
else
fputc(' ', f);
name = seccomp_syscall_resolve_num_arch(SCMP_ARCH_NATIVE, PTR_TO_INT(id) - 1);
fputs(strna(name), f);
}
#endif
fputc('\n', f);
}
if (c->syscall_archs) {
#ifdef HAVE_SECCOMP
Iterator j;
void *id;
#endif
fprintf(f,
"%sSystemCallArchitectures:",
prefix);
#ifdef HAVE_SECCOMP
SET_FOREACH(id, c->syscall_archs, j)
fprintf(f, " %s", strna(seccomp_arch_to_string(PTR_TO_UINT32(id) - 1)));
#endif
fputc('\n', f);
}
if (exec_context_restrict_namespaces_set(c)) {
_cleanup_free_ char *s = NULL;
r = namespace_flag_to_string_many(c->restrict_namespaces, &s);
if (r >= 0)
fprintf(f, "%sRestrictNamespaces: %s\n",
prefix, s);
}
if (c->syscall_errno > 0)
fprintf(f,
"%sSystemCallErrorNumber: %s\n",
prefix, strna(errno_to_name(c->syscall_errno)));
if (c->apparmor_profile)
fprintf(f,
"%sAppArmorProfile: %s%s\n",
prefix, c->apparmor_profile_ignore ? "-" : "", c->apparmor_profile);
}
bool exec_context_maintains_privileges(ExecContext *c) {
assert(c);
/* Returns true if the process forked off would run under
* an unchanged UID or as root. */
if (!c->user)
return true;
if (streq(c->user, "root") || streq(c->user, "0"))
return true;
return false;
}
void exec_status_start(ExecStatus *s, pid_t pid) {
assert(s);
zero(*s);
s->pid = pid;
dual_timestamp_get(&s->start_timestamp);
}
void exec_status_exit(ExecStatus *s, ExecContext *context, pid_t pid, int code, int status) {
assert(s);
if (s->pid && s->pid != pid)
zero(*s);
s->pid = pid;
dual_timestamp_get(&s->exit_timestamp);
s->code = code;
s->status = status;
if (context) {
if (context->utmp_id)
utmp_put_dead_process(context->utmp_id, pid, code, status);
exec_context_tty_reset(context, NULL);
}
}
void exec_status_dump(ExecStatus *s, FILE *f, const char *prefix) {
char buf[FORMAT_TIMESTAMP_MAX];
assert(s);
assert(f);
if (s->pid <= 0)
return;
prefix = strempty(prefix);
fprintf(f,
"%sPID: "PID_FMT"\n",
prefix, s->pid);
if (dual_timestamp_is_set(&s->start_timestamp))
fprintf(f,
"%sStart Timestamp: %s\n",
prefix, format_timestamp(buf, sizeof(buf), s->start_timestamp.realtime));
if (dual_timestamp_is_set(&s->exit_timestamp))
fprintf(f,
"%sExit Timestamp: %s\n"
"%sExit Code: %s\n"
"%sExit Status: %i\n",
prefix, format_timestamp(buf, sizeof(buf), s->exit_timestamp.realtime),
prefix, sigchld_code_to_string(s->code),
prefix, s->status);
}
char *exec_command_line(char **argv) {
size_t k;
char *n, *p, **a;
bool first = true;
assert(argv);
k = 1;
STRV_FOREACH(a, argv)
k += strlen(*a)+3;
n = new(char, k);
if (!n)
return NULL;
p = n;
STRV_FOREACH(a, argv) {
if (!first)
*(p++) = ' ';
else
first = false;
if (strpbrk(*a, WHITESPACE)) {
*(p++) = '\'';
p = stpcpy(p, *a);
*(p++) = '\'';
} else
p = stpcpy(p, *a);
}
*p = 0;
/* FIXME: this doesn't really handle arguments that have
* spaces and ticks in them */
return n;
}
void exec_command_dump(ExecCommand *c, FILE *f, const char *prefix) {
_cleanup_free_ char *cmd = NULL;
const char *prefix2;
assert(c);
assert(f);
prefix = strempty(prefix);
prefix2 = strjoina(prefix, "\t");
cmd = exec_command_line(c->argv);
fprintf(f,
"%sCommand Line: %s\n",
prefix, cmd ? cmd : strerror(ENOMEM));
exec_status_dump(&c->exec_status, f, prefix2);
}
void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix) {
assert(f);
prefix = strempty(prefix);
LIST_FOREACH(command, c, c)
exec_command_dump(c, f, prefix);
}
void exec_command_append_list(ExecCommand **l, ExecCommand *e) {
ExecCommand *end;
assert(l);
assert(e);
if (*l) {
/* It's kind of important, that we keep the order here */
LIST_FIND_TAIL(command, *l, end);
LIST_INSERT_AFTER(command, *l, end, e);
} else
*l = e;
}
int exec_command_set(ExecCommand *c, const char *path, ...) {
va_list ap;
char **l, *p;
assert(c);
assert(path);
va_start(ap, path);
l = strv_new_ap(path, ap);
va_end(ap);
if (!l)
return -ENOMEM;
p = strdup(path);
if (!p) {
strv_free(l);
return -ENOMEM;
}
free(c->path);
c->path = p;
strv_free(c->argv);
c->argv = l;
return 0;
}
int exec_command_append(ExecCommand *c, const char *path, ...) {
_cleanup_strv_free_ char **l = NULL;
va_list ap;
int r;
assert(c);
assert(path);
va_start(ap, path);
l = strv_new_ap(path, ap);
va_end(ap);
if (!l)
return -ENOMEM;
r = strv_extend_strv(&c->argv, l, false);
if (r < 0)
return r;
return 0;
}
static int exec_runtime_allocate(ExecRuntime **rt) {
if (*rt)
return 0;
*rt = new0(ExecRuntime, 1);
if (!*rt)
return -ENOMEM;
(*rt)->n_ref = 1;
(*rt)->netns_storage_socket[0] = (*rt)->netns_storage_socket[1] = -1;
return 0;
}
int exec_runtime_make(ExecRuntime **rt, ExecContext *c, const char *id) {
int r;
assert(rt);
assert(c);
assert(id);
if (*rt)
return 1;
if (!c->private_network && !c->private_tmp)
return 0;
r = exec_runtime_allocate(rt);
if (r < 0)
return r;
if (c->private_network && (*rt)->netns_storage_socket[0] < 0) {
if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, (*rt)->netns_storage_socket) < 0)
return -errno;
}
if (c->private_tmp && !(*rt)->tmp_dir) {
r = setup_tmp_dirs(id, &(*rt)->tmp_dir, &(*rt)->var_tmp_dir);
if (r < 0)
return r;
}
return 1;
}
ExecRuntime *exec_runtime_ref(ExecRuntime *r) {
assert(r);
assert(r->n_ref > 0);
r->n_ref++;
return r;
}
ExecRuntime *exec_runtime_unref(ExecRuntime *r) {
if (!r)
return NULL;
assert(r->n_ref > 0);
r->n_ref--;
if (r->n_ref > 0)
return NULL;
free(r->tmp_dir);
free(r->var_tmp_dir);
safe_close_pair(r->netns_storage_socket);
return mfree(r);
}
int exec_runtime_serialize(Unit *u, ExecRuntime *rt, FILE *f, FDSet *fds) {
assert(u);
assert(f);
assert(fds);
if (!rt)
return 0;
if (rt->tmp_dir)
unit_serialize_item(u, f, "tmp-dir", rt->tmp_dir);
if (rt->var_tmp_dir)
unit_serialize_item(u, f, "var-tmp-dir", rt->var_tmp_dir);
if (rt->netns_storage_socket[0] >= 0) {
int copy;
copy = fdset_put_dup(fds, rt->netns_storage_socket[0]);
if (copy < 0)
return copy;
unit_serialize_item_format(u, f, "netns-socket-0", "%i", copy);
}
if (rt->netns_storage_socket[1] >= 0) {
int copy;
copy = fdset_put_dup(fds, rt->netns_storage_socket[1]);
if (copy < 0)
return copy;
unit_serialize_item_format(u, f, "netns-socket-1", "%i", copy);
}
return 0;
}
int exec_runtime_deserialize_item(Unit *u, ExecRuntime **rt, const char *key, const char *value, FDSet *fds) {
int r;
assert(rt);
assert(key);
assert(value);
if (streq(key, "tmp-dir")) {
char *copy;
r = exec_runtime_allocate(rt);
if (r < 0)
return log_oom();
copy = strdup(value);
if (!copy)
return log_oom();
free((*rt)->tmp_dir);
(*rt)->tmp_dir = copy;
} else if (streq(key, "var-tmp-dir")) {
char *copy;
r = exec_runtime_allocate(rt);
if (r < 0)
return log_oom();
copy = strdup(value);
if (!copy)
return log_oom();
free((*rt)->var_tmp_dir);
(*rt)->var_tmp_dir = copy;
} else if (streq(key, "netns-socket-0")) {
int fd;
r = exec_runtime_allocate(rt);
if (r < 0)
return log_oom();
if (safe_atoi(value, &fd) < 0 || !fdset_contains(fds, fd))
log_unit_debug(u, "Failed to parse netns socket value: %s", value);
else {
safe_close((*rt)->netns_storage_socket[0]);
(*rt)->netns_storage_socket[0] = fdset_remove(fds, fd);
}
} else if (streq(key, "netns-socket-1")) {
int fd;
r = exec_runtime_allocate(rt);
if (r < 0)
return log_oom();
if (safe_atoi(value, &fd) < 0 || !fdset_contains(fds, fd))
log_unit_debug(u, "Failed to parse netns socket value: %s", value);
else {
safe_close((*rt)->netns_storage_socket[1]);
(*rt)->netns_storage_socket[1] = fdset_remove(fds, fd);
}
} else
return 0;
return 1;
}
static void *remove_tmpdir_thread(void *p) {
_cleanup_free_ char *path = p;
(void) rm_rf(path, REMOVE_ROOT|REMOVE_PHYSICAL);
return NULL;
}
void exec_runtime_destroy(ExecRuntime *rt) {
int r;
if (!rt)
return;
/* If there are multiple users of this, let's leave the stuff around */
if (rt->n_ref > 1)
return;
if (rt->tmp_dir) {
log_debug("Spawning thread to nuke %s", rt->tmp_dir);
r = asynchronous_job(remove_tmpdir_thread, rt->tmp_dir);
if (r < 0) {
log_warning_errno(r, "Failed to nuke %s: %m", rt->tmp_dir);
free(rt->tmp_dir);
}
rt->tmp_dir = NULL;
}
if (rt->var_tmp_dir) {
log_debug("Spawning thread to nuke %s", rt->var_tmp_dir);
r = asynchronous_job(remove_tmpdir_thread, rt->var_tmp_dir);
if (r < 0) {
log_warning_errno(r, "Failed to nuke %s: %m", rt->var_tmp_dir);
free(rt->var_tmp_dir);
}
rt->var_tmp_dir = NULL;
}
safe_close_pair(rt->netns_storage_socket);
}
static const char* const exec_input_table[_EXEC_INPUT_MAX] = {
[EXEC_INPUT_NULL] = "null",
[EXEC_INPUT_TTY] = "tty",
[EXEC_INPUT_TTY_FORCE] = "tty-force",
[EXEC_INPUT_TTY_FAIL] = "tty-fail",
[EXEC_INPUT_SOCKET] = "socket",
[EXEC_INPUT_NAMED_FD] = "fd",
};
DEFINE_STRING_TABLE_LOOKUP(exec_input, ExecInput);
static const char* const exec_output_table[_EXEC_OUTPUT_MAX] = {
[EXEC_OUTPUT_INHERIT] = "inherit",
[EXEC_OUTPUT_NULL] = "null",
[EXEC_OUTPUT_TTY] = "tty",
[EXEC_OUTPUT_SYSLOG] = "syslog",
[EXEC_OUTPUT_SYSLOG_AND_CONSOLE] = "syslog+console",
[EXEC_OUTPUT_KMSG] = "kmsg",
[EXEC_OUTPUT_KMSG_AND_CONSOLE] = "kmsg+console",
[EXEC_OUTPUT_JOURNAL] = "journal",
[EXEC_OUTPUT_JOURNAL_AND_CONSOLE] = "journal+console",
[EXEC_OUTPUT_SOCKET] = "socket",
[EXEC_OUTPUT_NAMED_FD] = "fd",
};
DEFINE_STRING_TABLE_LOOKUP(exec_output, ExecOutput);
static const char* const exec_utmp_mode_table[_EXEC_UTMP_MODE_MAX] = {
[EXEC_UTMP_INIT] = "init",
[EXEC_UTMP_LOGIN] = "login",
[EXEC_UTMP_USER] = "user",
};
DEFINE_STRING_TABLE_LOOKUP(exec_utmp_mode, ExecUtmpMode);
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