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-rw-r--r--execute.c361
-rw-r--r--execute.h15
-rw-r--r--load-fragment.c6
-rw-r--r--service.c83
-rw-r--r--service.h3
-rw-r--r--socket.c2
6 files changed, 407 insertions, 63 deletions
diff --git a/execute.c b/execute.c
index 4c6aa4eea9..bdb0f92179 100644
--- a/execute.c
+++ b/execute.c
@@ -32,6 +32,8 @@
#include <linux/sched.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <grp.h>
+#include <pwd.h>
#include "execute.h"
#include "strv.h"
@@ -293,7 +295,217 @@ static int setup_input(const ExecContext *context) {
}
}
-int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds, unsigned n_fds, pid_t *ret) {
+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)
+ if (prctl(PR_SET_SECUREBITS, context->secure_bits|SECURE_KEEP_CAPS) < 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(const ExecCommand *command,
+ const ExecContext *context,
+ int *fds, unsigned n_fds,
+ bool apply_permissions,
+ bool apply_chroot,
+ pid_t *ret) {
+
pid_t pid;
assert(command);
@@ -301,15 +513,19 @@ int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds,
assert(ret);
assert(fds || n_fds <= 0);
- log_debug("about to execute %s", command->path);
+ log_debug("About to execute %s", command->path);
if ((pid = fork()) < 0)
return -errno;
if (pid == 0) {
- char **e, **f = NULL;
int i, r;
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;
/* child */
@@ -348,17 +564,6 @@ int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds,
}
}
- 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;
- }
-
if (context->nice_set)
if (setpriority(PRIO_PROCESS, 0, context->nice) < 0) {
r = EXIT_NICE;
@@ -396,6 +601,51 @@ int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds,
goto fail;
}
+ if (context->user) {
+ username = context->user;
+ if (get_user_creds(&username, &uid, &gid, &home) < 0) {
+ r = EXIT_USER;
+ goto fail;
+ }
+ }
+
+ if (apply_permissions)
+ if (enforce_groups(context, username, uid) < 0) {
+ r = EXIT_GROUP;
+ goto fail;
+ }
+
+ 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_fds(fds, n_fds) < 0 ||
shift_fds(fds, n_fds) < 0 ||
flags_fds(fds, n_fds, context->non_blocking) < 0) {
@@ -403,59 +653,78 @@ int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds,
goto fail;
}
- for (i = 0; i < RLIMIT_NLIMITS; i++) {
- if (!context->rlimit[i])
- continue;
+ if (apply_permissions) {
- if (setrlimit(i, context->rlimit[i]) < 0) {
- r = EXIT_LIMITS;
- goto fail;
+ 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->secure_bits) {
+ if (context->user)
+ if (enforce_user(context, uid) < 0) {
+ r = EXIT_USER;
+ goto fail;
+ }
+
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 (n_fds > 0) {
- char a[64], b[64];
- char *listen_env[3] = {
- a,
- b,
- NULL
- };
+ if (!(our_env = new0(char*, 6))) {
+ r = EXIT_MEMORY;
+ goto fail;
+ }
- snprintf(a, sizeof(a), "LISTEN_PID=%llu", (unsigned long long) getpid());
- snprintf(b, sizeof(b), "LISTEN_FDS=%u", n_fds);
+ 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;
+ }
- a[sizeof(a)-1] = 0;
- b[sizeof(b)-1] = 0;
+ if (home)
+ if (asprintf(our_env + n_env++, "HOME=%s", home) < 0) {
+ r = EXIT_MEMORY;
+ goto fail;
+ }
- if (context->environment) {
- if (!(f = strv_merge(listen_env, context->environment))) {
- r = EXIT_MEMORY;
- goto fail;
- }
- e = f;
- } else
- e = listen_env;
+ 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;
+ }
- } else
- e = context->environment;
+ if (!(final_env = strv_env_merge(environ, our_env, context->environment, NULL))) {
+ r = EXIT_MEMORY;
+ goto fail;
+ }
- execve(command->path, command->argv, e);
+ execve(command->path, command->argv, final_env);
r = EXIT_EXEC;
fail:
- strv_free(f);
+ strv_free(our_env);
+ strv_free(final_env);
+
_exit(r);
}
- log_debug("executed %s as %llu", command->path, (unsigned long long) pid);
+ log_debug("Forked %s as %llu", command->path, (unsigned long long) pid);
*ret = pid;
return 0;
diff --git a/execute.h b/execute.h
index 3e332105c1..d64111b156 100644
--- a/execute.h
+++ b/execute.h
@@ -97,7 +97,6 @@ struct ExecContext {
int syslog_priority;
char *syslog_identifier;
- /* FIXME: all privs related settings need to be enforced */
cap_t capabilities;
int secure_bits;
uint64_t capability_bounding_set_drop;
@@ -137,16 +136,24 @@ typedef enum ExitStatus {
EXIT_SIGNAL_MASK,
EXIT_INPUT,
EXIT_OUTPUT,
- EXIT_CHROOT,
+ EXIT_CHROOT, /* 210 */
EXIT_PGID,
EXIT_IOPRIO,
EXIT_TIMERSLACK,
EXIT_SECUREBITS,
EXIT_SETSCHEDULER,
- EXIT_CPUAFFINITY
+ EXIT_CPUAFFINITY,
+ EXIT_GROUP,
+ EXIT_USER,
+ EXIT_CAPABILITIES
} ExitStatus;
-int exec_spawn(const ExecCommand *command, const ExecContext *context, int *fds, unsigned n_fds, pid_t *ret);
+int exec_spawn(const ExecCommand *command,
+ const ExecContext *context,
+ int *fds, unsigned n_fds,
+ bool apply_permissions,
+ bool apply_chroot,
+ pid_t *ret);
void exec_command_free_list(ExecCommand *c);
void exec_command_free_array(ExecCommand **c, unsigned n);
diff --git a/load-fragment.c b/load-fragment.c
index e002bf5ad1..1e98004c39 100644
--- a/load-fragment.c
+++ b/load-fragment.c
@@ -1094,6 +1094,8 @@ static int load_from_path(Unit *u, const char *path) {
{ "TimeoutSec", config_parse_usec, &u->service.timeout_usec, "Service" },
{ "Type", config_parse_service_type, &u->service, "Service" },
{ "Restart", config_parse_service_restart, &u->service, "Service" },
+ { "PermissionsStartOnly", config_parse_bool, &u->service.permissions_start_only, "Service" },
+ { "RootDirectoryStartOnly", config_parse_bool, &u->service.root_directory_start_only, "Service" },
EXEC_CONTEXT_CONFIG_ITEMS(u->service.exec_context, "Service"),
{ "ListenStream", config_parse_listen, &u->socket, "Socket" },
@@ -1250,7 +1252,9 @@ int unit_load_fragment(Unit *u) {
else
c = NULL;
- if (c && (c->output == EXEC_OUTPUT_KERNEL || c->output == EXEC_OUTPUT_SYSLOG)) {
+ if (c &&
+ (c->output == EXEC_OUTPUT_KERNEL || c->output == EXEC_OUTPUT_SYSLOG) &&
+ u->meta.manager->running_as != MANAGER_SESSION) {
int k;
/* If syslog or kernel logging is requested, make sure
diff --git a/service.c b/service.c
index a983e0db93..ca6e04500c 100644
--- a/service.c
+++ b/service.c
@@ -557,6 +557,8 @@ static int service_init(Unit *u) {
s->state = SERVICE_DEAD;
s->sysv_start_priority = -1;
+ s->permissions_start_only = false;
+ s->root_directory_start_only = false;
RATELIMIT_INIT(s->ratelimit, 10*USEC_PER_SEC, 5);
@@ -595,8 +597,12 @@ static void service_dump(Unit *u, FILE *f, const char *prefix) {
prefix2 = p2 ? p2 : prefix;
fprintf(f,
- "%sService State: %s\n",
- prefix, service_state_to_string(s->state));
+ "%sService State: %s\n"
+ "%sPermissionsStartOnly: %s\n"
+ "%sRootDirectoryStartOnly: %s\n",
+ prefix, service_state_to_string(s->state),
+ prefix, yes_no(s->permissions_start_only),
+ prefix, yes_no(s->root_directory_start_only));
if (s->pid_file)
fprintf(f,
@@ -859,7 +865,15 @@ fail:
return r;
}
-static int service_spawn(Service *s, ExecCommand *c, bool timeout, bool pass_fds, pid_t *_pid) {
+static int service_spawn(
+ Service *s,
+ ExecCommand *c,
+ bool timeout,
+ bool pass_fds,
+ bool apply_permissions,
+ bool apply_chroot,
+ pid_t *_pid) {
+
pid_t pid;
int r;
int *fds = NULL;
@@ -879,7 +893,12 @@ static int service_spawn(Service *s, ExecCommand *c, bool timeout, bool pass_fds
} else
unit_unwatch_timer(UNIT(s), &s->timer_watch);
- if ((r = exec_spawn(c, &s->exec_context, fds, n_fds, &pid)) < 0)
+ if ((r = exec_spawn(c,
+ &s->exec_context,
+ fds, n_fds,
+ apply_permissions,
+ apply_chroot,
+ &pid)) < 0)
goto fail;
if ((r = unit_watch_pid(UNIT(s), pid)) < 0)
@@ -935,7 +954,13 @@ static void service_enter_stop_post(Service *s, bool success) {
s->failure = true;
if ((s->control_command = s->exec_command[SERVICE_EXEC_STOP_POST]))
- if ((r = service_spawn(s, s->control_command, true, false, &s->control_pid)) < 0)
+ if ((r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ &s->control_pid)) < 0)
goto fail;
@@ -1011,7 +1036,13 @@ static void service_enter_stop(Service *s, bool success) {
s->failure = true;
if ((s->control_command = s->exec_command[SERVICE_EXEC_STOP]))
- if ((r = service_spawn(s, s->control_command, true, false, &s->control_pid)) < 0)
+ if ((r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ &s->control_pid)) < 0)
goto fail;
service_set_state(s, SERVICE_STOP);
@@ -1031,7 +1062,13 @@ static void service_enter_start_post(Service *s) {
assert(s);
if ((s->control_command = s->exec_command[SERVICE_EXEC_START_POST]))
- if ((r = service_spawn(s, s->control_command, true, false, &s->control_pid)) < 0)
+ if ((r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ &s->control_pid)) < 0)
goto fail;
@@ -1056,7 +1093,13 @@ static void service_enter_start(Service *s) {
assert(s->exec_command[SERVICE_EXEC_START]);
assert(!s->exec_command[SERVICE_EXEC_START]->command_next);
- if ((r = service_spawn(s, s->exec_command[SERVICE_EXEC_START], s->type == SERVICE_FORKING, true, &pid)) < 0)
+ if ((r = service_spawn(s,
+ s->exec_command[SERVICE_EXEC_START],
+ s->type == SERVICE_FORKING,
+ true,
+ true,
+ true,
+ &pid)) < 0)
goto fail;
service_set_state(s, SERVICE_START);
@@ -1099,7 +1142,13 @@ static void service_enter_start_pre(Service *s) {
assert(s);
if ((s->control_command = s->exec_command[SERVICE_EXEC_START_PRE]))
- if ((r = service_spawn(s, s->control_command, true, false, &s->control_pid)) < 0)
+ if ((r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ &s->control_pid)) < 0)
goto fail;
service_set_state(s, SERVICE_START_PRE);
@@ -1137,7 +1186,13 @@ static void service_enter_reload(Service *s) {
assert(s);
if ((s->control_command = s->exec_command[SERVICE_EXEC_RELOAD]))
- if ((r = service_spawn(s, s->control_command, true, false, &s->control_pid)) < 0)
+ if ((r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ &s->control_pid)) < 0)
goto fail;
service_set_state(s, SERVICE_RELOAD);
@@ -1164,7 +1219,13 @@ static void service_run_next(Service *s, bool success) {
s->control_command = s->control_command->command_next;
- if ((r = service_spawn(s, s->control_command, true, false, &s->control_pid)) < 0)
+ if ((r = service_spawn(s,
+ s->control_command,
+ true,
+ false,
+ !s->permissions_start_only,
+ !s->root_directory_start_only,
+ &s->control_pid)) < 0)
goto fail;
return;
diff --git a/service.h b/service.h
index 0c0850a81f..632e5eae4d 100644
--- a/service.h
+++ b/service.h
@@ -88,6 +88,9 @@ struct Service {
ExecCommand* exec_command[_SERVICE_EXEC_MAX];
ExecContext exec_context;
+ bool permissions_start_only;
+ bool root_directory_start_only;
+
ServiceState state;
ExecStatus main_exec_status;
diff --git a/socket.c b/socket.c
index b979e58d39..aec0d392a6 100644
--- a/socket.c
+++ b/socket.c
@@ -394,7 +394,7 @@ static int socket_spawn(Socket *s, ExecCommand *c, bool timeout, pid_t *_pid) {
} else
unit_unwatch_timer(UNIT(s), &s->timer_watch);
- if ((r = exec_spawn(c, &s->exec_context, NULL, 0, &pid)) < 0)
+ if ((r = exec_spawn(c, &s->exec_context, NULL, 0, true, true, &pid)) < 0)
goto fail;
if ((r = unit_watch_pid(UNIT(s), pid)) < 0)
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-04 13:51:17 +0000