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15ae422b74
systemd/execute.c
Lennart Poettering 15ae422b74 execute: support basic filesystem namespacing
2010-04-21 22:15:06 +02:00

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/*-*- Mode: C; c-basic-offset: 8 -*-*/
/***
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 General Public License as published by
the Free Software Foundation; either version 2 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <assert.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <signal.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/prctl.h>
#include <linux/sched.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <grp.h>
#include <pwd.h>
#include <sys/mount.h>
#include "execute.h"
#include "strv.h"
#include "macro.h"
#include "util.h"
#include "log.h"
#include "ioprio.h"
#include "securebits.h"
#include "cgroup.h"
#include "namespace.h"
/* This assumes there is a 'tty' group */
#define TTY_MODE 0620
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;
if ((nfd = fcntl(fds[i], F_DUPFD, i+3)) < 0)
return -errno;
close_nointr_nofail(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++) {
if ((r = fd_nonblock(fds[i], nonblock)) < 0)
return r;
/* We unconditionally drop FD_CLOEXEC from the fds,
* since after all we want to pass these fds to our
* children */
if ((r = fd_cloexec(fds[i], false)) < 0)
return r;
}
return 0;
}
static const char *tty_path(const ExecContext *context) {
assert(context);
if (context->tty_path)
return context->tty_path;
return "/dev/console";
}
static int open_null_as(int flags, int nfd) {
int fd, r;
assert(nfd >= 0);
if ((fd = open("/dev/null", flags|O_NOCTTY)) < 0)
return -errno;
if (fd != nfd) {
r = dup2(fd, nfd) < 0 ? -errno : nfd;
close_nointr_nofail(fd);
} else
r = nfd;
return r;
}
static int connect_logger_as(const ExecContext *context, ExecOutput output, const char *ident, int nfd) {
int fd, r;
union {
struct sockaddr sa;
struct sockaddr_un un;
} sa;
assert(context);
assert(output < _EXEC_OUTPUT_MAX);
assert(ident);
assert(nfd >= 0);
if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
return -errno;
zero(sa);
sa.sa.sa_family = AF_UNIX;
strncpy(sa.un.sun_path+1, LOGGER_SOCKET, sizeof(sa.un.sun_path)-1);
if (connect(fd, &sa.sa, sizeof(sa)) < 0) {
close_nointr_nofail(fd);
return -errno;
}
if (shutdown(fd, SHUT_RD) < 0) {
close_nointr_nofail(fd);
return -errno;
}
/* We speak a very simple protocol between log server
* and client: one line for the log destination (kmsg
* or syslog), followed by the priority field,
* followed by the process name. Since we replaced
* stdin/stderr we simple use stdio to write to
* it. Note that we use stderr, to minimize buffer
* flushing issues. */
dprintf(fd,
"%s\n"
"%i\n"
"%s\n",
output == EXEC_OUTPUT_KERNEL ? "kmsg" : "syslog",
context->syslog_priority,
context->syslog_identifier ? context->syslog_identifier : ident);
if (fd != nfd) {
r = dup2(fd, nfd) < 0 ? -errno : nfd;
close_nointr_nofail(fd);
} else
r = nfd;
return r;
}
static int open_terminal_as(const char *path, mode_t mode, int nfd) {
int fd, r;
assert(path);
assert(nfd >= 0);
if ((fd = open_terminal(path, mode | O_NOCTTY)) < 0)
return fd;
if (fd != nfd) {
r = dup2(fd, nfd) < 0 ? -errno : nfd;
close_nointr_nofail(fd);
} else
r = nfd;
return r;
}
static bool is_terminal_input(ExecInput i) {
return
i == EXEC_INPUT_TTY ||
i == EXEC_INPUT_TTY_FORCE ||
i == EXEC_INPUT_TTY_FAIL;
}
static int fixup_input(const ExecContext *context, int socket_fd) {
assert(context);
if (socket_fd < 0 && context->std_input == EXEC_INPUT_SOCKET)
return EXEC_INPUT_NULL;
return context->std_input;
}
static int fixup_output(const ExecContext *context, int socket_fd) {
assert(context);
if (socket_fd < 0 && context->std_output == EXEC_OUTPUT_SOCKET)
return EXEC_OUTPUT_INHERIT;
return context->std_output;
}
static int fixup_error(const ExecContext *context, int socket_fd) {
assert(context);
if (socket_fd < 0 && context->std_error == EXEC_OUTPUT_SOCKET)
return EXEC_OUTPUT_INHERIT;
return context->std_error;
}
static int setup_input(const ExecContext *context, int socket_fd) {
ExecInput i;
assert(context);
i = fixup_input(context, socket_fd);
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;
if ((fd = acquire_terminal(
tty_path(context),
i == EXEC_INPUT_TTY_FAIL,
i == EXEC_INPUT_TTY_FORCE)) < 0)
return fd;
if (fd != STDIN_FILENO) {
r = dup2(fd, STDIN_FILENO) < 0 ? -errno : STDIN_FILENO;
close_nointr_nofail(fd);
} else
r = STDIN_FILENO;
return r;
}
case EXEC_INPUT_SOCKET:
return dup2(socket_fd, STDIN_FILENO) < 0 ? -errno : STDIN_FILENO;
default:
assert_not_reached("Unknown input type");
}
}
static int setup_output(const ExecContext *context, int socket_fd, const char *ident) {
ExecOutput o;
ExecInput i;
assert(context);
assert(ident);
i = fixup_input(context, socket_fd);
o = fixup_output(context, socket_fd);
/* This expects the input is already set up */
switch (o) {
case EXEC_OUTPUT_INHERIT:
/* If the input is connected to a terminal, inherit that... */
if (is_terminal_input(i) || i == EXEC_INPUT_SOCKET)
return dup2(STDIN_FILENO, STDOUT_FILENO) < 0 ? -errno : STDOUT_FILENO;
return STDIN_FILENO;
case EXEC_OUTPUT_NULL:
return open_null_as(O_WRONLY, STDOUT_FILENO);
case EXEC_OUTPUT_TTY:
if (is_terminal_input(i))
return dup2(STDIN_FILENO, STDOUT_FILENO) < 0 ? -errno : STDOUT_FILENO;
/* We don't reset the terminal if this is just about output */
return open_terminal_as(tty_path(context), O_WRONLY, STDOUT_FILENO);
case EXEC_OUTPUT_SYSLOG:
case EXEC_OUTPUT_KERNEL:
return connect_logger_as(context, o, ident, STDOUT_FILENO);
case EXEC_OUTPUT_SOCKET:
assert(socket_fd >= 0);
return dup2(socket_fd, STDOUT_FILENO) < 0 ? -errno : STDOUT_FILENO;
default:
assert_not_reached("Unknown output type");
}
}
static int setup_error(const ExecContext *context, int socket_fd, const char *ident) {
ExecOutput o, e;
ExecInput i;
assert(context);
assert(ident);
i = fixup_input(context, socket_fd);
o = fixup_output(context, socket_fd);
e = fixup_error(context, 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 &&
!is_terminal_input(i))
return STDERR_FILENO;
/* Duplicate form stdout if possible */
if (e == o || e == EXEC_OUTPUT_INHERIT)
return dup2(STDOUT_FILENO, STDERR_FILENO) < 0 ? -errno : STDERR_FILENO;
switch (e) {
case EXEC_OUTPUT_NULL:
return open_null_as(O_WRONLY, STDERR_FILENO);
case EXEC_OUTPUT_TTY:
if (is_terminal_input(i))
return dup2(STDIN_FILENO, STDERR_FILENO) < 0 ? -errno : STDERR_FILENO;
/* We don't reset the terminal if this is just about output */
return open_terminal_as(tty_path(context), O_WRONLY, STDERR_FILENO);
case EXEC_OUTPUT_SYSLOG:
case EXEC_OUTPUT_KERNEL:
return connect_logger_as(context, e, ident, STDERR_FILENO);
case EXEC_OUTPUT_SOCKET:
assert(socket_fd >= 0);
return dup2(socket_fd, STDERR_FILENO) < 0 ? -errno : STDERR_FILENO;
default:
assert_not_reached("Unknown error type");
}
}
static int chown_terminal(int fd, uid_t uid) {
struct stat st;
assert(fd >= 0);
/* This might fail. What matters are the results. */
fchown(fd, uid, -1);
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 ExecContext *context,
int *_saved_stdin,
int *_saved_stdout) {
int fd = -1, saved_stdin, saved_stdout = -1, r;
assert(context);
assert(_saved_stdin);
assert(_saved_stdout);
/* This returns positive EXIT_xxx return values instead of
* negative errno style values! */
if ((saved_stdin = fcntl(STDIN_FILENO, F_DUPFD, 3)) < 0)
return EXIT_STDIN;
if ((saved_stdout = fcntl(STDOUT_FILENO, F_DUPFD, 3)) < 0) {
r = EXIT_STDOUT;
goto fail;
}
if ((fd = acquire_terminal(
tty_path(context),
context->std_input == EXEC_INPUT_TTY_FAIL,
context->std_input == EXEC_INPUT_TTY_FORCE)) < 0) {
r = EXIT_STDIN;
goto fail;
}
if (chown_terminal(fd, getuid()) < 0) {
r = EXIT_STDIN;
goto fail;
}
if (dup2(fd, STDIN_FILENO) < 0) {
r = EXIT_STDIN;
goto fail;
}
if (dup2(fd, STDOUT_FILENO) < 0) {
r = EXIT_STDOUT;
goto fail;
}
if (fd >= 2)
close_nointr_nofail(fd);
*_saved_stdin = saved_stdin;
*_saved_stdout = saved_stdout;
return 0;
fail:
if (saved_stdout >= 0)
close_nointr_nofail(saved_stdout);
if (saved_stdin >= 0)
close_nointr_nofail(saved_stdin);
if (fd >= 0)
close_nointr_nofail(fd);
return r;
}
static int restore_conform_stdio(const ExecContext *context,
int *saved_stdin,
int *saved_stdout,
bool *keep_stdin,
bool *keep_stdout) {
assert(context);
assert(saved_stdin);
assert(*saved_stdin >= 0);
assert(saved_stdout);
assert(*saved_stdout >= 0);
/* This returns positive EXIT_xxx return values instead of
* negative errno style values! */
if (is_terminal_input(context->std_input)) {
/* The service wants terminal input. */
*keep_stdin = true;
*keep_stdout =
context->std_output == EXEC_OUTPUT_INHERIT ||
context->std_output == EXEC_OUTPUT_TTY;
} else {
/* If the service doesn't want a controlling terminal,
* then we need to get rid entirely of what we have
* already. */
if (release_terminal() < 0)
return EXIT_STDIN;
if (dup2(*saved_stdin, STDIN_FILENO) < 0)
return EXIT_STDIN;
if (dup2(*saved_stdout, STDOUT_FILENO) < 0)
return EXIT_STDOUT;
*keep_stdout = *keep_stdin = false;
}
return 0;
}
static int get_group_creds(const char *groupname, gid_t *gid) {
struct group *g;
unsigned long lu;
assert(groupname);
assert(gid);
/* We enforce some special rules for gid=0: in order to avoid
* NSS lookups for root we hardcode its data. */
if (streq(groupname, "root") || streq(groupname, "0")) {
*gid = 0;
return 0;
}
if (safe_atolu(groupname, &lu) >= 0) {
errno = 0;
g = getgrgid((gid_t) lu);
} else {
errno = 0;
g = getgrnam(groupname);
}
if (!g)
return errno != 0 ? -errno : -ESRCH;
*gid = g->gr_gid;
return 0;
}
static int get_user_creds(const char **username, uid_t *uid, gid_t *gid, const char **home) {
struct passwd *p;
unsigned long lu;
assert(username);
assert(*username);
assert(uid);
assert(gid);
assert(home);
/* We enforce some special rules for uid=0: in order to avoid
* NSS lookups for root we hardcode its data. */
if (streq(*username, "root") || streq(*username, "0")) {
*username = "root";
*uid = 0;
*gid = 0;
*home = "/root";
return 0;
}
if (safe_atolu(*username, &lu) >= 0) {
errno = 0;
p = getpwuid((uid_t) lu);
/* If there are multiple users with the same id, make
* sure to leave $USER to the configured value instead
* of the first occurence in the database. However if
* the uid was configured by a numeric uid, then let's
* pick the real username from /etc/passwd. */
if (*username && p)
*username = p->pw_name;
} else {
errno = 0;
p = getpwnam(*username);
}
if (!p)
return errno != 0 ? -errno : -ESRCH;
*uid = p->pw_uid;
*gid = p->pw_gid;
*home = p->pw_dir;
return 0;
}
static int enforce_groups(const ExecContext *context, const char *username, gid_t gid) {
bool keep_groups = false;
int r;
assert(context);
/* Lookup and ser GID and supplementary group list. Here too
* we avoid NSS lookups for gid=0. */
if (context->group || username) {
if (context->group)
if ((r = get_group_creds(context->group, &gid)) < 0)
return r;
/* First step, initialize groups from /etc/groups */
if (username && gid != 0) {
if (initgroups(username, gid) < 0)
return -errno;
keep_groups = true;
}
/* Second step, set our gids */
if (setresgid(gid, gid, gid) < 0)
return -errno;
}
if (context->supplementary_groups) {
int ngroups_max, k;
gid_t *gids;
char **i;
/* Final step, initialize any manually set supplementary groups */
ngroups_max = (int) sysconf(_SC_NGROUPS_MAX);
if (!(gids = new(gid_t, ngroups_max)))
return -ENOMEM;
if (keep_groups) {
if ((k = getgroups(ngroups_max, gids)) < 0) {
free(gids);
return -errno;
}
} else
k = 0;
STRV_FOREACH(i, context->supplementary_groups) {
if (k >= ngroups_max) {
free(gids);
return -E2BIG;
}
if ((r = get_group_creds(*i, gids+k)) < 0) {
free(gids);
return r;
}
k++;
}
if (setgroups(k, gids) < 0) {
free(gids);
return -errno;
}
free(gids);
}
return 0;
}
static int enforce_user(const ExecContext *context, uid_t uid) {
int r;
assert(context);
/* Sets (but doesn't lookup) the uid and make sure we keep the
* capabilities while doing so. */
if (context->capabilities) {
cap_t d;
static const cap_value_t bits[] = {
CAP_SETUID, /* Necessary so that we can run setresuid() below */
CAP_SETPCAP /* Necessary so that we can set PR_SET_SECUREBITS later on */
};
/* First step: If we need to keep capabilities but
* drop privileges we need to make sure we keep our
* caps, whiel we drop priviliges. */
if (uid != 0) {
int sb = context->secure_bits|SECURE_KEEP_CAPS;
if (prctl(PR_GET_SECUREBITS) != sb)
if (prctl(PR_SET_SECUREBITS, sb) < 0)
return -errno;
}
/* Second step: set the capabilites. This will reduce
* the capabilities to the minimum we need. */
if (!(d = cap_dup(context->capabilities)))
return -errno;
if (cap_set_flag(d, CAP_EFFECTIVE, ELEMENTSOF(bits), bits, CAP_SET) < 0 ||
cap_set_flag(d, CAP_PERMITTED, ELEMENTSOF(bits), bits, CAP_SET) < 0) {
r = -errno;
cap_free(d);
return r;
}
if (cap_set_proc(d) < 0) {
r = -errno;
cap_free(d);
return r;
}
cap_free(d);
}
/* Third 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;
}
int exec_spawn(ExecCommand *command,
char **argv,
const ExecContext *context,
int fds[], unsigned n_fds,
bool apply_permissions,
bool apply_chroot,
bool confirm_spawn,
CGroupBonding *cgroup_bondings,
pid_t *ret) {
pid_t pid;
int r;
char *line;
int socket_fd;
assert(command);
assert(context);
assert(ret);
assert(fds || n_fds <= 0);
if (context->std_input == EXEC_INPUT_SOCKET ||
context->std_output == EXEC_OUTPUT_SOCKET ||
context->std_error == EXEC_OUTPUT_SOCKET) {
if (n_fds != 1)
return -EINVAL;
socket_fd = fds[0];
fds = NULL;
n_fds = 0;
} else
socket_fd = -1;
if (!argv)
argv = command->argv;
if (!(line = exec_command_line(argv)))
return -ENOMEM;
log_debug("About to execute: %s", line);
free(line);
if (cgroup_bondings)
if ((r = cgroup_bonding_realize_list(cgroup_bondings)))
return r;
if ((pid = fork()) < 0)
return -errno;
if (pid == 0) {
int i;
sigset_t ss;
const char *username = NULL, *home = NULL;
uid_t uid = (uid_t) -1;
gid_t gid = (gid_t) -1;
char **our_env = NULL, **final_env = NULL;
unsigned n_env = 0;
int saved_stdout = -1, saved_stdin = -1;
bool keep_stdout = false, keep_stdin = false;
/* child */
reset_all_signal_handlers();
if (sigemptyset(&ss) < 0 ||
sigprocmask(SIG_SETMASK, &ss, NULL) < 0) {
r = EXIT_SIGNAL_MASK;
goto fail;
}
if (!context->no_setsid)
if (setsid() < 0) {
r = EXIT_SETSID;
goto fail;
}
if (confirm_spawn) {
char response;
/* Set up terminal for the question */
if ((r = setup_confirm_stdio(context,
&saved_stdin, &saved_stdout)))
goto fail;
/* Now ask the question. */
if (!(line = exec_command_line(argv))) {
r = EXIT_MEMORY;
goto fail;
}
r = ask(&response, "yns", "Execute %s? [Yes, No, Skip] ", line);
free(line);
if (r < 0 || response == 'n') {
r = EXIT_CONFIRM;
goto fail;
} else if (response == 's') {
r = 0;
goto fail;
}
/* Release terminal for the question */
if ((r = restore_conform_stdio(context,
&saved_stdin, &saved_stdout,
&keep_stdin, &keep_stdout)))
goto fail;
}
if (!keep_stdin)
if (setup_input(context, socket_fd) < 0) {
r = EXIT_STDIN;
goto fail;
}
if (!keep_stdout)
if (setup_output(context, socket_fd, file_name_from_path(command->path)) < 0) {
r = EXIT_STDOUT;
goto fail;
}
if (setup_error(context, socket_fd, file_name_from_path(command->path)) < 0) {
r = EXIT_STDERR;
goto fail;
}
if (cgroup_bondings)
if ((r = cgroup_bonding_install_list(cgroup_bondings, 0)) < 0) {
r = EXIT_CGROUP;
goto fail;
}
if (context->oom_adjust_set) {
char t[16];
snprintf(t, sizeof(t), "%i", context->oom_adjust);
char_array_0(t);
if (write_one_line_file("/proc/self/oom_adj", t) < 0) {
r = EXIT_OOM_ADJUST;
goto fail;
}
}
if (context->nice_set)
if (setpriority(PRIO_PROCESS, 0, context->nice) < 0) {
r = EXIT_NICE;
goto fail;
}
if (context->cpu_sched_set) {
struct sched_param param;
zero(param);
param.sched_priority = context->cpu_sched_priority;
if (sched_setscheduler(0, context->cpu_sched_policy |
(context->cpu_sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0), &param) < 0) {
r = EXIT_SETSCHEDULER;
goto fail;
}
}
if (context->cpu_affinity_set)
if (sched_setaffinity(0, sizeof(context->cpu_affinity), &context->cpu_affinity) < 0) {
r = EXIT_CPUAFFINITY;
goto fail;
}
if (context->ioprio_set)
if (ioprio_set(IOPRIO_WHO_PROCESS, 0, context->ioprio) < 0) {
r = EXIT_IOPRIO;
goto fail;
}
if (context->timer_slack_ns_set)
if (prctl(PR_SET_TIMERSLACK, context->timer_slack_ns_set) < 0) {
r = EXIT_TIMERSLACK;
goto fail;
}
if (strv_length(context->read_write_dirs) > 0 ||
strv_length(context->read_only_dirs) > 0 ||
strv_length(context->inaccessible_dirs) > 0 ||
context->mount_flags != MS_SHARED ||
context->private_tmp)
if ((r = setup_namespace(
context->read_write_dirs,
context->read_only_dirs,
context->inaccessible_dirs,
context->private_tmp,
context->mount_flags)) < 0)
goto fail;
if (context->user) {
username = context->user;
if (get_user_creds(&username, &uid, &gid, &home) < 0) {
r = EXIT_USER;
goto fail;
}
if (is_terminal_input(context->std_input))
if (chown_terminal(STDIN_FILENO, uid) < 0) {
r = EXIT_STDIN;
goto fail;
}
}
if (apply_permissions)
if (enforce_groups(context, username, uid) < 0) {
r = EXIT_GROUP;
goto fail;
}
umask(context->umask);
if (apply_chroot) {
if (context->root_directory)
if (chroot(context->root_directory) < 0) {
r = EXIT_CHROOT;
goto fail;
}
if (chdir(context->working_directory ? context->working_directory : "/") < 0) {
r = EXIT_CHDIR;
goto fail;
}
} else {
char *d;
if (asprintf(&d, "%s/%s",
context->root_directory ? context->root_directory : "",
context->working_directory ? context->working_directory : "") < 0) {
r = EXIT_MEMORY;
goto fail;
}
if (chdir(d) < 0) {
free(d);
r = EXIT_CHDIR;
goto fail;
}
free(d);
}
if (close_all_fds(fds, n_fds) < 0 ||
shift_fds(fds, n_fds) < 0 ||
flags_fds(fds, n_fds, context->non_blocking) < 0) {
r = EXIT_FDS;
goto fail;
}
if (apply_permissions) {
for (i = 0; i < RLIMIT_NLIMITS; i++) {
if (!context->rlimit[i])
continue;
if (setrlimit(i, context->rlimit[i]) < 0) {
r = EXIT_LIMITS;
goto fail;
}
}
if (context->user)
if (enforce_user(context, uid) < 0) {
r = EXIT_USER;
goto fail;
}
/* PR_GET_SECUREBITS is not priviliged, 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) != context->secure_bits)
if (prctl(PR_SET_SECUREBITS, context->secure_bits) < 0) {
r = EXIT_SECUREBITS;
goto fail;
}
if (context->capabilities)
if (cap_set_proc(context->capabilities) < 0) {
r = EXIT_CAPABILITIES;
goto fail;
}
}
if (!(our_env = new0(char*, 6))) {
r = EXIT_MEMORY;
goto fail;
}
if (n_fds > 0)
if (asprintf(our_env + n_env++, "LISTEN_PID=%llu", (unsigned long long) getpid()) < 0 ||
asprintf(our_env + n_env++, "LISTEN_FDS=%u", n_fds) < 0) {
r = EXIT_MEMORY;
goto fail;
}
if (home)
if (asprintf(our_env + n_env++, "HOME=%s", home) < 0) {
r = EXIT_MEMORY;
goto fail;
}
if (username)
if (asprintf(our_env + n_env++, "LOGNAME=%s", username) < 0 ||
asprintf(our_env + n_env++, "USER=%s", username) < 0) {
r = EXIT_MEMORY;
goto fail;
}
if (!(final_env = strv_env_merge(environ, our_env, context->environment, NULL))) {
r = EXIT_MEMORY;
goto fail;
}
execve(command->path, argv, final_env);
r = EXIT_EXEC;
fail:
strv_free(our_env);
strv_free(final_env);
if (saved_stdin >= 0)
close_nointr_nofail(saved_stdin);
if (saved_stdout >= 0)
close_nointr_nofail(saved_stdout);
_exit(r);
}
/* 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 (cgroup_bondings)
if ((r = cgroup_bonding_install_list(cgroup_bondings, pid)) < 0) {
r = EXIT_CGROUP;
goto fail;
}
log_debug("Forked %s as %llu", command->path, (unsigned long long) pid);
command->exec_status.pid = pid;
command->exec_status.start_timestamp = now(CLOCK_REALTIME);
*ret = pid;
return 0;
}
void exec_context_init(ExecContext *c) {
assert(c);
c->umask = 0002;
c->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 0);
c->cpu_sched_policy = SCHED_OTHER;
c->syslog_priority = LOG_DAEMON|LOG_INFO;
c->mount_flags = MS_SHARED;
}
void exec_context_done(ExecContext *c) {
unsigned l;
assert(c);
strv_free(c->environment);
c->environment = NULL;
for (l = 0; l < ELEMENTSOF(c->rlimit); l++) {
free(c->rlimit[l]);
c->rlimit[l] = NULL;
}
free(c->working_directory);
c->working_directory = NULL;
free(c->root_directory);
c->root_directory = NULL;
free(c->tty_path);
c->tty_path = NULL;
free(c->syslog_identifier);
c->syslog_identifier = NULL;
free(c->user);
c->user = NULL;
free(c->group);
c->group = NULL;
strv_free(c->supplementary_groups);
c->supplementary_groups = NULL;
if (c->capabilities) {
cap_free(c->capabilities);
c->capabilities = NULL;
}
strv_free(c->read_only_dirs);
c->read_only_dirs = NULL;
strv_free(c->read_write_dirs);
c->read_write_dirs = NULL;
strv_free(c->inaccessible_dirs);
c->inaccessible_dirs = NULL;
}
void exec_command_done(ExecCommand *c) {
assert(c);
free(c->path);
c->path = NULL;
strv_free(c->argv);
c->argv = NULL;
}
void exec_command_done_array(ExecCommand *c, unsigned n) {
unsigned i;
for (i = 0; i < n; i++)
exec_command_done(c+i);
}
void exec_command_free_list(ExecCommand *c) {
ExecCommand *i;
while ((i = c)) {
LIST_REMOVE(ExecCommand, command, c, i);
exec_command_done(i);
free(i);
}
}
void exec_command_free_array(ExecCommand **c, unsigned n) {
unsigned i;
for (i = 0; i < n; i++) {
exec_command_free_list(c[i]);
c[i] = NULL;
}
}
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;
unsigned i;
assert(c);
assert(f);
if (!prefix)
prefix = "";
fprintf(f,
"%sUMask: %04o\n"
"%sWorkingDirectory: %s\n"
"%sRootDirectory: %s\n"
"%sNonBlocking: %s\n"
"%sPrivateTmp: %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));
if (c->environment)
for (e = c->environment; *e; e++)
fprintf(f, "%sEnvironment: %s\n", prefix, *e);
if (c->nice_set)
fprintf(f,
"%sNice: %i\n",
prefix, c->nice);
if (c->oom_adjust_set)
fprintf(f,
"%sOOMAdjust: %i\n",
prefix, c->oom_adjust);
for (i = 0; i < RLIM_NLIMITS; i++)
if (c->rlimit[i])
fprintf(f, "%s%s: %llu\n", prefix, rlimit_to_string(i), (unsigned long long) c->rlimit[i]->rlim_max);
if (c->ioprio_set)
fprintf(f,
"%sIOSchedulingClass: %s\n"
"%sIOPriority: %i\n",
prefix, ioprio_class_to_string(IOPRIO_PRIO_CLASS(c->ioprio)),
prefix, (int) IOPRIO_PRIO_DATA(c->ioprio));
if (c->cpu_sched_set)
fprintf(f,
"%sCPUSchedulingPolicy: %s\n"
"%sCPUSchedulingPriority: %i\n"
"%sCPUSchedulingResetOnFork: %s\n",
prefix, sched_policy_to_string(c->cpu_sched_policy),
prefix, c->cpu_sched_priority,
prefix, yes_no(c->cpu_sched_reset_on_fork));
if (c->cpu_affinity_set) {
fprintf(f, "%sCPUAffinity:", prefix);
for (i = 0; i < CPU_SETSIZE; i++)
if (CPU_ISSET(i, &c->cpu_affinity))
fprintf(f, " %i", i);
fputs("\n", f);
}
if (c->timer_slack_ns_set)
fprintf(f, "%sTimerSlackNS: %lu\n", prefix, c->timer_slack_ns);
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",
prefix, c->tty_path);
if (c->std_output == EXEC_OUTPUT_SYSLOG || c->std_output == EXEC_OUTPUT_KERNEL ||
c->std_error == EXEC_OUTPUT_SYSLOG || c->std_error == EXEC_OUTPUT_KERNEL)
fprintf(f,
"%sSyslogFacility: %s\n"
"%sSyslogLevel: %s\n",
prefix, log_facility_to_string(LOG_FAC(c->syslog_priority)),
prefix, log_level_to_string(LOG_PRI(c->syslog_priority)));
if (c->capabilities) {
char *t;
if ((t = cap_to_text(c->capabilities, NULL))) {
fprintf(f, "%sCapabilities: %s\n",
prefix, t);
cap_free(t);
}
}
if (c->secure_bits)
fprintf(f, "%sSecure Bits:%s%s%s%s%s%s\n",
prefix,
(c->secure_bits & SECURE_KEEP_CAPS) ? " keep-caps" : "",
(c->secure_bits & SECURE_KEEP_CAPS_LOCKED) ? " keep-caps-locked" : "",
(c->secure_bits & SECURE_NO_SETUID_FIXUP) ? " no-setuid-fixup" : "",
(c->secure_bits & SECURE_NO_SETUID_FIXUP_LOCKED) ? " no-setuid-fixup-locked" : "",
(c->secure_bits & SECURE_NOROOT) ? " noroot" : "",
(c->secure_bits & SECURE_NOROOT_LOCKED) ? "noroot-locked" : "");
if (c->capability_bounding_set_drop) {
fprintf(f, "%sCapabilityBoundingSetDrop:", prefix);
for (i = 0; i <= CAP_LAST_CAP; i++)
if (c->capability_bounding_set_drop & (1 << i)) {
char *t;
if ((t = cap_to_name(i))) {
fprintf(f, " %s", t);
free(t);
}
}
fputs("\n", f);
}
if (c->user)
fprintf(f, "%sUser: %s", prefix, c->user);
if (c->group)
fprintf(f, "%sGroup: %s", prefix, c->group);
if (strv_length(c->supplementary_groups) > 0) {
fprintf(f, "%sSupplementaryGroups:", prefix);
strv_fprintf(f, c->supplementary_groups);
fputs("\n", f);
}
if (strv_length(c->read_write_dirs) > 0) {
fprintf(f, "%sReadWriteDirs:", prefix);
strv_fprintf(f, c->read_write_dirs);
fputs("\n", f);
}
if (strv_length(c->read_only_dirs) > 0) {
fprintf(f, "%sReadOnlyDirs:", prefix);
strv_fprintf(f, c->read_only_dirs);
fputs("\n", f);
}
if (strv_length(c->inaccessible_dirs) > 0) {
fprintf(f, "%sInaccessibleDirs:", prefix);
strv_fprintf(f, c->inaccessible_dirs);
fputs("\n", f);
}
}
void exec_status_fill(ExecStatus *s, pid_t pid, int code, int status) {
assert(s);
s->pid = pid;
s->exit_timestamp = now(CLOCK_REALTIME);
s->code = code;
s->status = status;
}
void exec_status_dump(ExecStatus *s, FILE *f, const char *prefix) {
char buf[FORMAT_TIMESTAMP_MAX];
assert(s);
assert(f);
if (!prefix)
prefix = "";
if (s->pid <= 0)
return;
fprintf(f,
"%sPID: %llu\n",
prefix, (unsigned long long) s->pid);
if (s->start_timestamp > 0)
fprintf(f,
"%sStart Timestamp: %s\n",
prefix, format_timestamp(buf, sizeof(buf), s->start_timestamp));
if (s->exit_timestamp > 0)
fprintf(f,
"%sExit Timestamp: %s\n"
"%sExit Code: %s\n"
"%sExit Status: %i\n",
prefix, format_timestamp(buf, sizeof(buf), s->exit_timestamp),
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;
if (!(n = new(char, k)))
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) {
char *p2;
const char *prefix2;
char *cmd;
assert(c);
assert(f);
if (!prefix)
prefix = "";
p2 = strappend(prefix, "\t");
prefix2 = p2 ? p2 : prefix;
cmd = exec_command_line(c->argv);
fprintf(f,
"%sCommand Line: %s\n",
prefix, cmd ? cmd : strerror(ENOMEM));
free(cmd);
exec_status_dump(&c->exec_status, f, prefix2);
free(p2);
}
void exec_command_dump_list(ExecCommand *c, FILE *f, const char *prefix) {
assert(f);
if (!prefix)
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 kinda important that we keep the order here */
LIST_FIND_TAIL(ExecCommand, command, *l, end);
LIST_INSERT_AFTER(ExecCommand, 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;
if (!(p = strdup(path))) {
strv_free(l);
return -ENOMEM;
}
free(c->path);
c->path = p;
strv_free(c->argv);
c->argv = l;
return 0;
}
const char* exit_status_to_string(ExitStatus status) {
/* We cast to int here, so that -Wenum doesn't complain that
* EXIT_SUCCESS/EXIT_FAILURE aren't in the enum */
switch ((int) status) {
case EXIT_SUCCESS:
return "SUCCESS";
case EXIT_FAILURE:
return "FAILURE";
case EXIT_INVALIDARGUMENT:
return "INVALIDARGUMENT";
case EXIT_NOTIMPLEMENTED:
return "NOTIMPLEMENTED";
case EXIT_NOPERMISSION:
return "NOPERMISSION";
case EXIT_NOTINSTALLED:
return "NOTINSSTALLED";
case EXIT_NOTCONFIGURED:
return "NOTCONFIGURED";
case EXIT_NOTRUNNING:
return "NOTRUNNING";
case EXIT_CHDIR:
return "CHDIR";
case EXIT_NICE:
return "NICE";
case EXIT_FDS:
return "FDS";
case EXIT_EXEC:
return "EXEC";
case EXIT_MEMORY:
return "MEMORY";
case EXIT_LIMITS:
return "LIMITS";
case EXIT_OOM_ADJUST:
return "OOM_ADJUST";
case EXIT_SIGNAL_MASK:
return "SIGNAL_MASK";
case EXIT_STDIN:
return "STDIN";
case EXIT_STDOUT:
return "STDOUT";
case EXIT_CHROOT:
return "CHROOT";
case EXIT_IOPRIO:
return "IOPRIO";
case EXIT_TIMERSLACK:
return "TIMERSLACK";
case EXIT_SECUREBITS:
return "SECUREBITS";
case EXIT_SETSCHEDULER:
return "SETSCHEDULER";
case EXIT_CPUAFFINITY:
return "CPUAFFINITY";
case EXIT_GROUP:
return "GROUP";
case EXIT_USER:
return "USER";
case EXIT_CAPABILITIES:
return "CAPABILITIES";
case EXIT_CGROUP:
return "CGROUP";
case EXIT_SETSID:
return "SETSID";
case EXIT_CONFIRM:
return "CONFIRM";
case EXIT_STDERR:
return "STDERR";
default:
return NULL;
}
}
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"
};
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_KERNEL] = "kernel",
[EXEC_OUTPUT_SOCKET] = "socket"
};
DEFINE_STRING_TABLE_LOOKUP(exec_output, ExecOutput);
DEFINE_STRING_TABLE_LOOKUP(exec_input, ExecInput);
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