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-rw-r--r--man/systemd.exec.xml60
-rw-r--r--src/core/dbus-execute.c5
-rw-r--r--src/core/dbus-mount.c2
-rw-r--r--src/core/dbus-service.c3
-rw-r--r--src/core/dbus-socket.c2
-rw-r--r--src/core/dbus-swap.c2
-rw-r--r--src/core/execute.c46
-rw-r--r--src/core/execute.h1
-rw-r--r--src/core/manager.c411
-rw-r--r--src/core/manager.h23
-rw-r--r--src/core/mount.c2
-rw-r--r--src/core/service.c3
-rw-r--r--src/core/socket.c2
-rw-r--r--src/core/swap.c2
-rw-r--r--src/core/unit.c174
-rw-r--r--src/core/unit.h18
-rw-r--r--src/login/logind-user.c11
-rw-r--r--src/shared/bus-unit-util.c2
-rw-r--r--src/shared/clean-ipc.c66
-rw-r--r--src/shared/clean-ipc.h4
-rw-r--r--src/test/test-ipcrm.c2
21 files changed, 777 insertions, 64 deletions
diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index bf82326096..bcedebd5bb 100644
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -160,14 +160,14 @@
use. However, UID/GIDs are recycled after a unit is terminated. Care should be taken that any processes running
as part of a unit for which dynamic users/groups are enabled do not leave files or directories owned by these
users/groups around, as a different unit might get the same UID/GID assigned later on, and thus gain access to
- these files or directories. If <varname>DynamicUser=</varname> is enabled, <varname>PrivateTmp=</varname> is
- implied. This ensures that the lifetime of temporary files created by the executed processes is bound to the
- runtime of the service, and hence the lifetime of the dynamic user/group. Since <filename>/tmp</filename> and
- <filename>/var/tmp</filename> are usually the only world-writable directories on a system this ensures that a
- unit making use of dynamic user/group allocation cannot leave files around after unit termination. Use
- <varname>RuntimeDirectory=</varname> (see below) in order to assign a writable runtime directory to a service,
- owned by the dynamic user/group and removed automatically when the unit is terminated. Defaults to
- off.</para></listitem>
+ these files or directories. If <varname>DynamicUser=</varname> is enabled, <varname>RemoveIPC=</varname> and
+ <varname>PrivateTmp=</varname> are implied. This ensures that the lifetime of IPC objects and temporary files
+ created by the executed processes is bound to the runtime of the service, and hence the lifetime of the dynamic
+ user/group. Since <filename>/tmp</filename> and <filename>/var/tmp</filename> are usually the only
+ world-writable directories on a system this ensures that a unit making use of dynamic user/group allocation
+ cannot leave files around after unit termination. Use <varname>RuntimeDirectory=</varname> (see below) in order
+ to assign a writable runtime directory to a service, owned by the dynamic user/group and removed automatically
+ when the unit is terminated. Defaults to off.</para></listitem>
</varlistentry>
<varlistentry>
@@ -186,6 +186,18 @@
</varlistentry>
<varlistentry>
+ <term><varname>RemoveIPC=</varname></term>
+
+ <listitem><para>Takes a boolean parameter. If set, all System V and POSIX IPC objects owned by the user and
+ group the processes of this unit are run as are removed when the unit is stopped. This setting only has an
+ effect if at least one of <varname>User=</varname>, <varname>Group=</varname> and
+ <varname>DynamicUser=</varname> are used. It has no effect on IPC objects owned by the root user. Specifically,
+ this removes System V semaphores, as well as System V and POSIX shared memory segments and message queues. If
+ multiple units use the same user or group the IPC objects are removed when the last of these units is
+ stopped. This setting is implied if <varname>DynamicUser=</varname> is set.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><varname>Nice=</varname></term>
<listitem><para>Sets the default nice level (scheduling
@@ -920,27 +932,19 @@
<varlistentry>
<term><varname>PrivateTmp=</varname></term>
- <listitem><para>Takes a boolean argument. If true, sets up a
- new file system namespace for the executed processes and
- mounts private <filename>/tmp</filename> and
- <filename>/var/tmp</filename> directories inside it that is
- not shared by processes outside of the namespace. This is
- useful to secure access to temporary files of the process, but
- makes sharing between processes via <filename>/tmp</filename>
- or <filename>/var/tmp</filename> impossible. If this is
- enabled, all temporary files created by a service in these
- directories will be removed after the service is stopped.
- Defaults to false. It is possible to run two or more units
- within the same private <filename>/tmp</filename> and
- <filename>/var/tmp</filename> namespace by using the
+ <listitem><para>Takes a boolean argument. If true, sets up a new file system namespace for the executed
+ processes and mounts private <filename>/tmp</filename> and <filename>/var/tmp</filename> directories inside it
+ that is not shared by processes outside of the namespace. This is useful to secure access to temporary files of
+ the process, but makes sharing between processes via <filename>/tmp</filename> or <filename>/var/tmp</filename>
+ impossible. If this is enabled, all temporary files created by a service in these directories will be removed
+ after the service is stopped. Defaults to false. It is possible to run two or more units within the same
+ private <filename>/tmp</filename> and <filename>/var/tmp</filename> namespace by using the
<varname>JoinsNamespaceOf=</varname> directive, see
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for details. Note that using this setting will disconnect
- propagation of mounts from the service to the host
- (propagation in the opposite direction continues to work).
- This means that this setting may not be used for services
- which shall be able to install mount points in the main mount
- namespace.</para></listitem>
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
+ details. Note that using this setting will disconnect propagation of mounts from the service to the host
+ (propagation in the opposite direction continues to work). This means that this setting may not be used for
+ services which shall be able to install mount points in the main mount namespace. This setting is implied if
+ <varname>DynamicUser=</varname> is set.</para></listitem>
</varlistentry>
<varlistentry>
diff --git a/src/core/dbus-execute.c b/src/core/dbus-execute.c
index e35d3ccd2e..7e33a2d201 100644
--- a/src/core/dbus-execute.c
+++ b/src/core/dbus-execute.c
@@ -695,6 +695,7 @@ const sd_bus_vtable bus_exec_vtable[] = {
SD_BUS_PROPERTY("User", "s", NULL, offsetof(ExecContext, user), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("Group", "s", NULL, offsetof(ExecContext, group), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("DynamicUser", "b", bus_property_get_bool, offsetof(ExecContext, dynamic_user), SD_BUS_VTABLE_PROPERTY_CONST),
+ SD_BUS_PROPERTY("RemoveIPC", "b", bus_property_get_bool, offsetof(ExecContext, remove_ipc), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("SupplementaryGroups", "as", NULL, offsetof(ExecContext, supplementary_groups), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("PAMName", "s", NULL, offsetof(ExecContext, pam_name), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("ReadWriteDirectories", "as", NULL, offsetof(ExecContext, read_write_paths), SD_BUS_VTABLE_PROPERTY_CONST|SD_BUS_VTABLE_HIDDEN),
@@ -1071,7 +1072,7 @@ int bus_exec_context_set_transient_property(
"IgnoreSIGPIPE", "TTYVHangup", "TTYReset",
"PrivateTmp", "PrivateDevices", "PrivateNetwork", "PrivateUsers",
"NoNewPrivileges", "SyslogLevelPrefix", "MemoryDenyWriteExecute",
- "RestrictRealtime", "DynamicUser")) {
+ "RestrictRealtime", "DynamicUser", "RemoveIPC")) {
int b;
r = sd_bus_message_read(message, "b", &b);
@@ -1103,6 +1104,8 @@ int bus_exec_context_set_transient_property(
c->restrict_realtime = b;
else if (streq(name, "DynamicUser"))
c->dynamic_user = b;
+ else if (streq(name, "RemoveIPC"))
+ c->remove_ipc = b;
unit_write_drop_in_private_format(u, mode, name, "%s=%s", name, yes_no(b));
}
diff --git a/src/core/dbus-mount.c b/src/core/dbus-mount.c
index b4bbee0648..3c6bda4073 100644
--- a/src/core/dbus-mount.c
+++ b/src/core/dbus-mount.c
@@ -117,6 +117,8 @@ const sd_bus_vtable bus_mount_vtable[] = {
SD_BUS_PROPERTY("DirectoryMode", "u", bus_property_get_mode, offsetof(Mount, directory_mode), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("SloppyOptions", "b", bus_property_get_bool, offsetof(Mount, sloppy_options), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("Result", "s", property_get_result, offsetof(Mount, result), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+ SD_BUS_PROPERTY("UID", "u", NULL, offsetof(Unit, ref_uid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+ SD_BUS_PROPERTY("GID", "u", NULL, offsetof(Unit, ref_gid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
BUS_EXEC_COMMAND_VTABLE("ExecMount", offsetof(Mount, exec_command[MOUNT_EXEC_MOUNT]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
BUS_EXEC_COMMAND_VTABLE("ExecUnmount", offsetof(Mount, exec_command[MOUNT_EXEC_UNMOUNT]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
BUS_EXEC_COMMAND_VTABLE("ExecRemount", offsetof(Mount, exec_command[MOUNT_EXEC_REMOUNT]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
diff --git a/src/core/dbus-service.c b/src/core/dbus-service.c
index 5eac876a6e..3c55e0f7fe 100644
--- a/src/core/dbus-service.c
+++ b/src/core/dbus-service.c
@@ -65,6 +65,9 @@ const sd_bus_vtable bus_service_vtable[] = {
SD_BUS_PROPERTY("Result", "s", property_get_result, offsetof(Service, result), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("USBFunctionDescriptors", "s", NULL, offsetof(Service, usb_function_descriptors), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("USBFunctionStrings", "s", NULL, offsetof(Service, usb_function_strings), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+ SD_BUS_PROPERTY("UID", "u", NULL, offsetof(Unit, ref_uid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+ SD_BUS_PROPERTY("GID", "u", NULL, offsetof(Unit, ref_gid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+
BUS_EXEC_STATUS_VTABLE("ExecMain", offsetof(Service, main_exec_status), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
BUS_EXEC_COMMAND_LIST_VTABLE("ExecStartPre", offsetof(Service, exec_command[SERVICE_EXEC_START_PRE]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
BUS_EXEC_COMMAND_LIST_VTABLE("ExecStart", offsetof(Service, exec_command[SERVICE_EXEC_START]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
diff --git a/src/core/dbus-socket.c b/src/core/dbus-socket.c
index 9a071a1355..21adb64e15 100644
--- a/src/core/dbus-socket.c
+++ b/src/core/dbus-socket.c
@@ -152,6 +152,8 @@ const sd_bus_vtable bus_socket_vtable[] = {
SD_BUS_PROPERTY("SocketProtocol", "i", bus_property_get_int, offsetof(Socket, socket_protocol), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("TriggerLimitIntervalUSec", "t", bus_property_get_usec, offsetof(Socket, trigger_limit.interval), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("TriggerLimitBurst", "u", bus_property_get_unsigned, offsetof(Socket, trigger_limit.burst), SD_BUS_VTABLE_PROPERTY_CONST),
+ SD_BUS_PROPERTY("UID", "u", NULL, offsetof(Unit, ref_uid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+ SD_BUS_PROPERTY("GID", "u", NULL, offsetof(Unit, ref_gid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
BUS_EXEC_COMMAND_LIST_VTABLE("ExecStartPre", offsetof(Socket, exec_command[SOCKET_EXEC_START_PRE]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
BUS_EXEC_COMMAND_LIST_VTABLE("ExecStartPost", offsetof(Socket, exec_command[SOCKET_EXEC_START_POST]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
BUS_EXEC_COMMAND_LIST_VTABLE("ExecStopPre", offsetof(Socket, exec_command[SOCKET_EXEC_STOP_PRE]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
diff --git a/src/core/dbus-swap.c b/src/core/dbus-swap.c
index 292f8738c6..85a2c26b98 100644
--- a/src/core/dbus-swap.c
+++ b/src/core/dbus-swap.c
@@ -84,6 +84,8 @@ const sd_bus_vtable bus_swap_vtable[] = {
SD_BUS_PROPERTY("TimeoutUSec", "t", bus_property_get_usec, offsetof(Swap, timeout_usec), SD_BUS_VTABLE_PROPERTY_CONST),
SD_BUS_PROPERTY("ControlPID", "u", bus_property_get_pid, offsetof(Swap, control_pid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
SD_BUS_PROPERTY("Result", "s", property_get_result, offsetof(Swap, result), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+ SD_BUS_PROPERTY("UID", "u", NULL, offsetof(Unit, ref_uid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
+ SD_BUS_PROPERTY("GID", "u", NULL, offsetof(Unit, ref_gid), SD_BUS_VTABLE_PROPERTY_EMITS_CHANGE),
BUS_EXEC_COMMAND_VTABLE("ExecActivate", offsetof(Swap, exec_command[SWAP_EXEC_ACTIVATE]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
BUS_EXEC_COMMAND_VTABLE("ExecDeactivate", offsetof(Swap, exec_command[SWAP_EXEC_DEACTIVATE]), SD_BUS_VTABLE_PROPERTY_EMITS_INVALIDATION),
SD_BUS_VTABLE_END
diff --git a/src/core/execute.c b/src/core/execute.c
index 18bb421cab..4c786a2e33 100644
--- a/src/core/execute.c
+++ b/src/core/execute.c
@@ -1723,11 +1723,12 @@ 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 + 11];
+ int dont_close[n_fds + 12];
assert(params);
@@ -1755,9 +1756,40 @@ static int close_remaining_fds(
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 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,
@@ -1769,6 +1801,7 @@ static int exec_child(
int socket_fd,
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;
@@ -1815,7 +1848,7 @@ static int exec_child(
log_forget_fds();
- r = close_remaining_fds(params, runtime, dcreds, socket_fd, fds, n_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;
@@ -1902,6 +1935,14 @@ static int exec_child(
}
}
+ 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)
@@ -2501,6 +2542,7 @@ int exec_spawn(Unit *unit,
socket_fd,
fds, n_fds,
files_env,
+ unit->manager->user_lookup_fds[1],
&exit_status);
if (r < 0) {
log_open();
diff --git a/src/core/execute.h b/src/core/execute.h
index 106154f81a..6082c42aba 100644
--- a/src/core/execute.h
+++ b/src/core/execute.h
@@ -178,6 +178,7 @@ struct ExecContext {
bool no_new_privileges;
bool dynamic_user;
+ bool remove_ipc;
/* This is not exposed to the user but available
* internally. We need it to make sure that whenever we spawn
diff --git a/src/core/manager.c b/src/core/manager.c
index c20e185d78..6f2477eef4 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -45,6 +45,7 @@
#include "bus-error.h"
#include "bus-kernel.h"
#include "bus-util.h"
+#include "clean-ipc.h"
#include "dbus-job.h"
#include "dbus-manager.h"
#include "dbus-unit.h"
@@ -81,6 +82,7 @@
#include "transaction.h"
#include "umask-util.h"
#include "unit-name.h"
+#include "user-util.h"
#include "util.h"
#include "virt.h"
#include "watchdog.h"
@@ -98,6 +100,7 @@ static int manager_dispatch_cgroups_agent_fd(sd_event_source *source, int fd, ui
static int manager_dispatch_signal_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
static int manager_dispatch_time_change_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
static int manager_dispatch_idle_pipe_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
+static int manager_dispatch_user_lookup_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata);
static int manager_dispatch_jobs_in_progress(sd_event_source *source, usec_t usec, void *userdata);
static int manager_dispatch_run_queue(sd_event_source *source, void *userdata);
static int manager_run_generators(Manager *m);
@@ -590,6 +593,8 @@ int manager_new(UnitFileScope scope, bool test_run, Manager **_m) {
m->dev_autofs_fd = m->private_listen_fd = m->kdbus_fd = m->cgroup_inotify_fd =
m->ask_password_inotify_fd = -1;
+ m->user_lookup_fds[0] = m->user_lookup_fds[1] = -1;
+
m->current_job_id = 1; /* start as id #1, so that we can leave #0 around as "null-like" value */
m->have_ask_password = -EINVAL; /* we don't know */
@@ -812,6 +817,59 @@ static int manager_setup_cgroups_agent(Manager *m) {
return 0;
}
+static int manager_setup_user_lookup_fd(Manager *m) {
+ int r;
+
+ assert(m);
+
+ /* Set up the socket pair used for passing UID/GID resolution results from forked off processes to PID
+ * 1. Background: we can't do name lookups (NSS) from PID 1, since it might involve IPC and thus activation,
+ * and we might hence deadlock on ourselves. Hence we do all user/group lookups asynchronously from the forked
+ * off processes right before executing the binaries to start. In order to be able to clean up any IPC objects
+ * created by a unit (see RemoveIPC=) we need to know in PID 1 the used UID/GID of the executed processes,
+ * hence we establish this communication channel so that forked off processes can pass their UID/GID
+ * information back to PID 1. The forked off processes send their resolved UID/GID to PID 1 in a simple
+ * datagram, along with their unit name, so that we can share one communication socket pair among all units for
+ * this purpose.
+ *
+ * You might wonder why we need a communication channel for this that is independent of the usual notification
+ * socket scheme (i.e. $NOTIFY_SOCKET). The primary difference is about trust: data sent via the $NOTIFY_SOCKET
+ * channel is only accepted if it originates from the right unit and if reception was enabled for it. The user
+ * lookup socket OTOH is only accessible by PID 1 and its children until they exec(), and always available.
+ *
+ * Note that this function is called under two circumstances: when we first initialize (in which case we
+ * allocate both the socket pair and the event source to listen on it), and when we deserialize after a reload
+ * (in which case the socket pair already exists but we still need to allocate the event source for it). */
+
+ if (m->user_lookup_fds[0] < 0) {
+
+ /* Free all secondary fields */
+ safe_close_pair(m->user_lookup_fds);
+ m->user_lookup_event_source = sd_event_source_unref(m->user_lookup_event_source);
+
+ if (socketpair(AF_UNIX, SOCK_DGRAM|SOCK_CLOEXEC, 0, m->user_lookup_fds) < 0)
+ return log_error_errno(errno, "Failed to allocate user lookup socket: %m");
+
+ (void) fd_inc_rcvbuf(m->user_lookup_fds[0], NOTIFY_RCVBUF_SIZE);
+ }
+
+ if (!m->user_lookup_event_source) {
+ r = sd_event_add_io(m->event, &m->user_lookup_event_source, m->user_lookup_fds[0], EPOLLIN, manager_dispatch_user_lookup_fd, m);
+ if (r < 0)
+ return log_error_errno(errno, "Failed to allocate user lookup event source: %m");
+
+ /* Process even earlier than the notify event source, so that we always know first about valid UID/GID
+ * resolutions */
+ r = sd_event_source_set_priority(m->user_lookup_event_source, SD_EVENT_PRIORITY_NORMAL-8);
+ if (r < 0)
+ return log_error_errno(errno, "Failed to set priority ot user lookup event source: %m");
+
+ (void) sd_event_source_set_description(m->user_lookup_event_source, "user-lookup");
+ }
+
+ return 0;
+}
+
static int manager_connect_bus(Manager *m, bool reexecuting) {
bool try_bus_connect;
@@ -853,8 +911,7 @@ enum {
_GC_OFFSET_MAX
};
-static void unit_gc_mark_good(Unit *u, unsigned gc_marker)
-{
+static void unit_gc_mark_good(Unit *u, unsigned gc_marker) {
Iterator i;
Unit *other;
@@ -1021,12 +1078,14 @@ Manager* manager_free(Manager *m) {
sd_event_source_unref(m->time_change_event_source);
sd_event_source_unref(m->jobs_in_progress_event_source);
sd_event_source_unref(m->run_queue_event_source);
+ sd_event_source_unref(m->user_lookup_event_source);
safe_close(m->signal_fd);
safe_close(m->notify_fd);
safe_close(m->cgroups_agent_fd);
safe_close(m->time_change_fd);
safe_close(m->kdbus_fd);
+ safe_close_pair(m->user_lookup_fds);
manager_close_ask_password(m);
@@ -1052,6 +1111,9 @@ Manager* manager_free(Manager *m) {
assert(hashmap_isempty(m->units_requiring_mounts_for));
hashmap_free(m->units_requiring_mounts_for);
+ hashmap_free(m->uid_refs);
+ hashmap_free(m->gid_refs);
+
free(m);
return NULL;
}
@@ -1221,6 +1283,10 @@ int manager_startup(Manager *m, FILE *serialization, FDSet *fds) {
if (q < 0 && r == 0)
r = q;
+ q = manager_setup_user_lookup_fd(m);
+ if (q < 0 && r == 0)
+ r = q;
+
/* We might have deserialized the kdbus control fd, but if we
* didn't, then let's create the bus now. */
manager_connect_bus(m, !!serialization);
@@ -1232,6 +1298,10 @@ int manager_startup(Manager *m, FILE *serialization, FDSet *fds) {
/* Release any dynamic users no longer referenced */
dynamic_user_vacuum(m, true);
+ /* Release any references to UIDs/GIDs no longer referenced, and destroy any IPC owned by them */
+ manager_vacuum_uid_refs(m);
+ manager_vacuum_gid_refs(m);
+
if (serialization) {
assert(m->n_reloading > 0);
m->n_reloading--;
@@ -2396,6 +2466,20 @@ int manager_serialize(Manager *m, FILE *f, FDSet *fds, bool switching_root) {
fprintf(f, "cgroups-agent-fd=%i\n", copy);
}
+ if (m->user_lookup_fds[0] >= 0) {
+ int copy0, copy1;
+
+ copy0 = fdset_put_dup(fds, m->user_lookup_fds[0]);
+ if (copy0 < 0)
+ return copy0;
+
+ copy1 = fdset_put_dup(fds, m->user_lookup_fds[1]);
+ if (copy1 < 0)
+ return copy1;
+
+ fprintf(f, "user-lookup=%i %i\n", copy0, copy1);
+ }
+
if (m->kdbus_fd >= 0) {
int copy;
@@ -2412,6 +2496,9 @@ int manager_serialize(Manager *m, FILE *f, FDSet *fds, bool switching_root) {
if (r < 0)
return r;
+ manager_serialize_uid_refs(m, f);
+ manager_serialize_gid_refs(m, f);
+
fputc('\n', f);
HASHMAP_FOREACH_KEY(u, t, m->units, i) {
@@ -2578,6 +2665,18 @@ int manager_deserialize(Manager *m, FILE *f, FDSet *fds) {
m->cgroups_agent_fd = fdset_remove(fds, fd);
}
+ } else if (startswith(l, "user-lookup=")) {
+ int fd0, fd1;
+
+ if (sscanf(l + 12, "%i %i", &fd0, &fd1) != 2 || fd0 < 0 || fd1 < 0 || fd0 == fd1 || !fdset_contains(fds, fd0) || !fdset_contains(fds, fd1))
+ log_debug("Failed to parse user lookup fd: %s", l + 12);
+ else {
+ m->user_lookup_event_source = sd_event_source_unref(m->user_lookup_event_source);
+ safe_close_pair(m->user_lookup_fds);
+ m->user_lookup_fds[0] = fdset_remove(fds, fd0);
+ m->user_lookup_fds[1] = fdset_remove(fds, fd1);
+ }
+
} else if (startswith(l, "kdbus-fd=")) {
int fd;
@@ -2590,6 +2689,10 @@ int manager_deserialize(Manager *m, FILE *f, FDSet *fds) {
} else if (startswith(l, "dynamic-user="))
dynamic_user_deserialize_one(m, l + 13, fds);
+ else if (startswith(l, "destroy-ipc-uid="))
+ manager_deserialize_uid_refs_one(m, l + 16);
+ else if (startswith(l, "destroy-ipc-gid="))
+ manager_deserialize_gid_refs_one(m, l + 16);
else {
int k;
@@ -2672,6 +2775,8 @@ int manager_reload(Manager *m) {
lookup_paths_flush_generator(&m->lookup_paths);
lookup_paths_free(&m->lookup_paths);
dynamic_user_vacuum(m, false);
+ m->uid_refs = hashmap_free(m->uid_refs);
+ m->gid_refs = hashmap_free(m->gid_refs);
q = lookup_paths_init(&m->lookup_paths, m->unit_file_scope, 0, NULL);
if (q < 0 && r >= 0)
@@ -2705,12 +2810,20 @@ int manager_reload(Manager *m) {
if (q < 0 && r >= 0)
r = q;
+ q = manager_setup_user_lookup_fd(m);
+ if (q < 0 && r >= 0)
+ r = q;
+
/* Third, fire things up! */
manager_coldplug(m);
/* Release any dynamic users no longer referenced */
dynamic_user_vacuum(m, true);
+ /* Release any references to UIDs/GIDs no longer referenced, and destroy any IPC owned by them */
+ manager_vacuum_uid_refs(m);
+ manager_vacuum_gid_refs(m);
+
/* Sync current state of bus names with our set of listening units */
if (m->api_bus)
manager_sync_bus_names(m, m->api_bus);
@@ -3144,6 +3257,300 @@ ManagerState manager_state(Manager *m) {
return MANAGER_RUNNING;
}
+#define DESTROY_IPC_FLAG (UINT32_C(1) << 31)
+
+static void manager_unref_uid_internal(
+ Manager *m,
+ Hashmap **uid_refs,
+ uid_t uid,
+ bool destroy_now,
+ int (*_clean_ipc)(uid_t uid)) {
+
+ uint32_t c, n;
+
+ assert(m);
+ assert(uid_refs);
+ assert(uid_is_valid(uid));
+ assert(_clean_ipc);
+
+ /* A generic implementation, covering both manager_unref_uid() and manager_unref_gid(), under the assumption
+ * that uid_t and gid_t are actually defined the same way, with the same validity rules.
+ *
+ * We store a hashmap where the UID/GID is they key and the value is a 32bit reference counter, whose highest
+ * bit is used as flag for marking UIDs/GIDs whose IPC objects to remove when the last reference to the UID/GID
+ * is dropped. The flag is set to on, once at least one reference from a unit where RemoveIPC= is set is added
+ * on a UID/GID. It is reset when the UID's/GID's reference counter drops to 0 again. */
+
+ assert_cc(sizeof(uid_t) == sizeof(gid_t));
+ assert_cc(UID_INVALID == (uid_t) GID_INVALID);
+
+ if (uid == 0) /* We don't keep track of root, and will never destroy it */
+ return;
+
+ c = PTR_TO_UINT32(hashmap_get(*uid_refs, UID_TO_PTR(uid)));
+
+ n = c & ~DESTROY_IPC_FLAG;
+ assert(n > 0);
+ n--;
+
+ if (destroy_now && n == 0) {
+ hashmap_remove(*uid_refs, UID_TO_PTR(uid));
+
+ if (c & DESTROY_IPC_FLAG) {
+ log_debug("%s " UID_FMT " is no longer referenced, cleaning up its IPC.",
+ _clean_ipc == clean_ipc_by_uid ? "UID" : "GID",
+ uid);
+ (void) _clean_ipc(uid);
+ }
+ } else {
+ c = n | (c & DESTROY_IPC_FLAG);
+ assert_se(hashmap_update(*uid_refs, UID_TO_PTR(uid), UINT32_TO_PTR(c)) >= 0);
+ }
+}
+
+void manager_unref_uid(Manager *m, uid_t uid, bool destroy_now) {
+ manager_unref_uid_internal(m, &m->uid_refs, uid, destroy_now, clean_ipc_by_uid);
+}
+
+void manager_unref_gid(Manager *m, gid_t gid, bool destroy_now) {
+ manager_unref_uid_internal(m, &m->gid_refs, (uid_t) gid, destroy_now, clean_ipc_by_gid);
+}
+
+static int manager_ref_uid_internal(
+ Manager *m,
+ Hashmap **uid_refs,
+ uid_t uid,
+ bool clean_ipc) {
+
+ uint32_t c, n;
+ int r;
+
+ assert(m);
+ assert(uid_refs);
+ assert(uid_is_valid(uid));
+
+ /* A generic implementation, covering both manager_ref_uid() and manager_ref_gid(), under the assumption
+ * that uid_t and gid_t are actually defined the same way, with the same validity rules. */
+
+ assert_cc(sizeof(uid_t) == sizeof(gid_t));
+ assert_cc(UID_INVALID == (uid_t) GID_INVALID);
+
+ if (uid == 0) /* We don't keep track of root, and will never destroy it */
+ return 0;
+
+ r = hashmap_ensure_allocated(uid_refs, &trivial_hash_ops);
+ if (r < 0)
+ return r;
+
+ c = PTR_TO_UINT32(hashmap_get(*uid_refs, UID_TO_PTR(uid)));
+
+ n = c & ~DESTROY_IPC_FLAG;
+ n++;
+
+ if (n & DESTROY_IPC_FLAG) /* check for overflow */
+ return -EOVERFLOW;
+
+ c = n | (c & DESTROY_IPC_FLAG) | (clean_ipc ? DESTROY_IPC_FLAG : 0);
+
+ return hashmap_replace(*uid_refs, UID_TO_PTR(uid), UINT32_TO_PTR(c));
+}
+
+int manager_ref_uid(Manager *m, uid_t uid, bool clean_ipc) {
+ return manager_ref_uid_internal(m, &m->uid_refs, uid, clean_ipc);
+}
+
+int manager_ref_gid(Manager *m, gid_t gid, bool clean_ipc) {
+ return manager_ref_uid_internal(m, &m->gid_refs, (uid_t) gid, clean_ipc);
+}
+
+static void manager_vacuum_uid_refs_internal(
+ Manager *m,
+ Hashmap **uid_refs,
+ int (*_clean_ipc)(uid_t uid)) {
+
+ Iterator i;
+ void *p, *k;
+
+ assert(m);
+ assert(uid_refs);
+ assert(_clean_ipc);
+
+ HASHMAP_FOREACH_KEY(p, k, *uid_refs, i) {
+ uint32_t c, n;
+ uid_t uid;
+
+ uid = PTR_TO_UID(k);
+ c = PTR_TO_UINT32(p);
+
+ n = c & ~DESTROY_IPC_FLAG;
+ if (n > 0)
+ continue;
+
+ if (c & DESTROY_IPC_FLAG) {
+ log_debug("Found unreferenced %s " UID_FMT " after reload/reexec. Cleaning up.",
+ _clean_ipc == clean_ipc_by_uid ? "UID" : "GID",
+ uid);
+ (void) _clean_ipc(uid);
+ }
+
+ assert_se(hashmap_remove(*uid_refs, k) == p);
+ }
+}
+
+void manager_vacuum_uid_refs(Manager *m) {
+ manager_vacuum_uid_refs_internal(m, &m->uid_refs, clean_ipc_by_uid);
+}
+
+void manager_vacuum_gid_refs(Manager *m) {
+ manager_vacuum_uid_refs_internal(m, &m->gid_refs, clean_ipc_by_gid);
+}
+
+static void manager_serialize_uid_refs_internal(
+ Manager *m,
+ FILE *f,
+ Hashmap **uid_refs,
+ const char *field_name) {
+
+ Iterator i;
+ void *p, *k;
+
+ assert(m);
+ assert(f);
+ assert(uid_refs);
+ assert(field_name);
+
+ /* Serialize the UID reference table. Or actually, just the IPC destruction flag of it, as the actual counter
+ * of it is better rebuild after a reload/reexec. */
+
+ HASHMAP_FOREACH_KEY(p, k, *uid_refs, i) {
+ uint32_t c;
+ uid_t uid;
+
+ uid = PTR_TO_UID(k);
+ c = PTR_TO_UINT32(p);
+
+ if (!(c & DESTROY_IPC_FLAG))
+ continue;
+
+ fprintf(f, "%s=" UID_FMT "\n", field_name, uid);
+ }
+}
+
+void manager_serialize_uid_refs(Manager *m, FILE *f) {
+ manager_serialize_uid_refs_internal(m, f, &m->uid_refs, "destroy-ipc-uid");
+}
+
+void manager_serialize_gid_refs(Manager *m, FILE *f) {
+ manager_serialize_uid_refs_internal(m, f, &m->gid_refs, "destroy-ipc-gid");
+}
+
+static void manager_deserialize_uid_refs_one_internal(
+ Manager *m,
+ Hashmap** uid_refs,
+ const char *value) {
+
+ uid_t uid;
+ uint32_t c;
+ int r;
+
+ assert(m);
+ assert(uid_refs);
+ assert(value);
+
+ r = parse_uid(value, &uid);
+ if (r < 0 || uid == 0) {
+ log_debug("Unable to parse UID reference serialization");
+ return;
+ }
+
+ r = hashmap_ensure_allocated(uid_refs, &trivial_hash_ops);
+ if (r < 0) {
+ log_oom();
+ return;
+ }
+
+ c = PTR_TO_UINT32(hashmap_get(*uid_refs, UID_TO_PTR(uid)));
+ if (c & DESTROY_IPC_FLAG)
+ return;
+
+ c |= DESTROY_IPC_FLAG;
+
+ r = hashmap_replace(*uid_refs, UID_TO_PTR(uid), UINT32_TO_PTR(c));
+ if (r < 0) {
+ log_debug("Failed to add UID reference entry");
+ return;
+ }
+}
+
+void manager_deserialize_uid_refs_one(Manager *m, const char *value) {
+ manager_deserialize_uid_refs_one_internal(m, &m->uid_refs, value);
+}
+
+void manager_deserialize_gid_refs_one(Manager *m, const char *value) {
+ manager_deserialize_uid_refs_one_internal(m, &m->gid_refs, value);
+}
+
+int manager_dispatch_user_lookup_fd(sd_event_source *source, int fd, uint32_t revents, void *userdata) {
+ struct buffer {
+ uid_t uid;
+ gid_t gid;
+ char unit_name[UNIT_NAME_MAX+1];
+ } _packed_ buffer;
+
+ Manager *m = userdata;
+ ssize_t l;
+ size_t n;
+ Unit *u;
+
+ assert_se(source);
+ assert_se(m);
+
+ /* Invoked whenever a child process succeeded resolving its user/group to use and sent us the resulting UID/GID
+ * in a datagram. We parse the datagram here and pass it off to the unit, so that it can add a reference to the
+ * UID/GID so that it can destroy the UID/GID's IPC objects when the reference counter drops to 0. */
+
+ l = recv(fd, &buffer, sizeof(buffer), MSG_DONTWAIT);
+ if (l < 0) {
+ if (errno == EINTR || errno == EAGAIN)
+ return 0;
+
+ return log_error_errno(errno, "Failed to read from user lookup fd: %m");
+ }
+
+ if ((size_t) l <= offsetof(struct buffer, unit_name)) {
+ log_warning("Received too short user lookup message, ignoring.");
+ return 0;
+ }
+
+ if ((size_t) l > offsetof(struct buffer, unit_name) + UNIT_NAME_MAX) {
+ log_warning("Received too long user lookup message, ignoring.");
+ return 0;
+ }
+
+ if (!uid_is_valid(buffer.uid) && !gid_is_valid(buffer.gid)) {
+ log_warning("Got user lookup message with invalid UID/GID pair, ignoring.");
+ return 0;
+ }
+
+ n = (size_t) l - offsetof(struct buffer, unit_name);
+ if (memchr(buffer.unit_name, 0, n)) {
+ log_warning("Received lookup message with embedded NUL character, ignoring.");
+ return 0;
+ }
+
+ buffer.unit_name[n] = 0;
+ u = manager_get_unit(m, buffer.unit_name);
+ if (!u) {
+ log_debug("Got user lookup message but unit doesn't exist, ignoring.");
+ return 0;
+ }
+
+ log_unit_debug(u, "User lookup succeeded: uid=" UID_FMT " gid=" GID_FMT, buffer.uid, buffer.gid);
+
+ unit_notify_user_lookup(u, buffer.uid, buffer.gid);
+ return 0;
+}
+
static const char *const manager_state_table[_MANAGER_STATE_MAX] = {
[MANAGER_INITIALIZING] = "initializing",
[MANAGER_STARTING] = "starting",
diff --git a/src/core/manager.h b/src/core/manager.h
index c681d5dc46..b9f2e4b5a1 100644
--- a/src/core/manager.h
+++ b/src/core/manager.h
@@ -143,6 +143,9 @@ struct Manager {
sd_event_source *jobs_in_progress_event_source;
+ int user_lookup_fds[2];
+ sd_event_source *user_lookup_event_source;
+
UnitFileScope unit_file_scope;
LookupPaths lookup_paths;
Set *unit_path_cache;
@@ -234,7 +237,6 @@ struct Manager {
bool dispatching_dbus_queue:1;
bool taint_usr:1;
-
bool test_run:1;
/* If non-zero, exit with the following value when the systemd
@@ -301,6 +303,10 @@ struct Manager {
/* Dynamic users/groups, indexed by their name */
Hashmap *dynamic_users;
+ /* Keep track of all UIDs and GIDs any of our services currently use. This is useful for the RemoveIPC= logic. */
+ Hashmap *uid_refs;
+ Hashmap *gid_refs;
+
/* When the user hits C-A-D more than 7 times per 2s, reboot immediately... */
RateLimit ctrl_alt_del_ratelimit;
@@ -378,5 +384,20 @@ ManagerState manager_state(Manager *m);
int manager_update_failed_units(Manager *m, Unit *u, bool failed);
+void manager_unref_uid(Manager *m, uid_t uid, bool destroy_now);
+int manager_ref_uid(Manager *m, uid_t uid, bool clean_ipc);
+
+void manager_unref_gid(Manager *m, gid_t gid, bool destroy_now);
+int manager_ref_gid(Manager *m, gid_t gid, bool destroy_now);
+
+void manager_vacuum_uid_refs(Manager *m);
+void manager_vacuum_gid_refs(Manager *m);
+
+void manager_serialize_uid_refs(Manager *m, FILE *f);
+void manager_deserialize_uid_refs_one(Manager *m, const char *value);
+
+void manager_serialize_gid_refs(Manager *m, FILE *f);
+void manager_deserialize_gid_refs_one(Manager *m, const char *value);
+
const char *manager_state_to_string(ManagerState m) _const_;
ManagerState manager_state_from_string(const char *s) _pure_;
diff --git a/src/core/mount.c b/src/core/mount.c
index f3ccf6d48a..f2ac8d171f 100644
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -769,6 +769,8 @@ static void mount_enter_dead(Mount *m, MountResult f) {
exec_context_destroy_runtime_directory(&m->exec_context, manager_get_runtime_prefix(UNIT(m)->manager));
+ unit_unref_uid_gid(UNIT(m), true);
+
dynamic_creds_destroy(&m->dynamic_creds);
}
diff --git a/src/core/service.c b/src/core/service.c
index 4a37702f52..1951ba9222 100644
--- a/src/core/service.c
+++ b/src/core/service.c
@@ -1471,6 +1471,9 @@ static void service_enter_dead(Service *s, ServiceResult f, bool allow_restart)
/* Also, remove the runtime directory */
exec_context_destroy_runtime_directory(&s->exec_context, manager_get_runtime_prefix(UNIT(s)->manager));
+ /* Get rid of the IPC bits of the user */
+ unit_unref_uid_gid(UNIT(s), true);
+
/* Release the user, and destroy it if we are the only remaining owner */
dynamic_creds_destroy(&s->dynamic_creds);
diff --git a/src/core/socket.c b/src/core/socket.c
index 50872e8366..70d55dd9ed 100644
--- a/src/core/socket.c
+++ b/src/core/socket.c
@@ -1905,6 +1905,8 @@ static void socket_enter_dead(Socket *s, SocketResult f) {
exec_context_destroy_runtime_directory(&s->exec_context, manager_get_runtime_prefix(UNIT(s)->manager));
+ unit_unref_uid_gid(UNIT(s), true);
+
dynamic_creds_destroy(&s->dynamic_creds);
}
diff --git a/src/core/swap.c b/src/core/swap.c
index 2c802da3b5..fb222b6858 100644
--- a/src/core/swap.c
+++ b/src/core/swap.c
@@ -683,6 +683,8 @@ static void swap_enter_dead(Swap *s, SwapResult f) {
exec_context_destroy_runtime_directory(&s->exec_context, manager_get_runtime_prefix(UNIT(s)->manager));
+ unit_unref_uid_gid(UNIT(s), true);
+
dynamic_creds_destroy(&s->dynamic_creds);
}
diff --git a/src/core/unit.c b/src/core/unit.c
index 952604e0db..4b8d81c3f1 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -100,7 +100,8 @@ Unit *unit_new(Manager *m, size_t size) {
u->on_failure_job_mode = JOB_REPLACE;
u->cgroup_inotify_wd = -1;
u->job_timeout = USEC_INFINITY;
- u->sigchldgen = 0;
+ u->ref_uid = UID_INVALID;
+ u->ref_gid = GID_INVALID;
RATELIMIT_INIT(u->start_limit, m->default_start_limit_interval, m->default_start_limit_burst);
RATELIMIT_INIT(u->auto_stop_ratelimit, 10 * USEC_PER_SEC, 16);
@@ -550,6 +551,8 @@ void unit_free(Unit *u) {
unit_release_cgroup(u);
+ unit_unref_uid_gid(u, false);
+
(void) manager_update_failed_units(u->manager, u, false);
set_remove(u->manager->startup_units, u);
@@ -2614,6 +2617,11 @@ int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
unit_serialize_item(u, f, "cgroup", u->cgroup_path);
unit_serialize_item(u, f, "cgroup-realized", yes_no(u->cgroup_realized));
+ if (uid_is_valid(u->ref_uid))
+ unit_serialize_item_format(u, f, "ref-uid", UID_FMT, u->ref_uid);
+ if (gid_is_valid(u->ref_gid))
+ unit_serialize_item_format(u, f, "ref-gid", GID_FMT, u->ref_gid);
+
if (serialize_jobs) {
if (u->job) {
fprintf(f, "job\n");
@@ -2851,6 +2859,28 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
u->cgroup_realized = b;
continue;
+
+ } else if (streq(l, "ref-uid")) {
+ uid_t uid;
+
+ r = parse_uid(v, &uid);
+ if (r < 0)
+ log_unit_debug(u, "Failed to parse referenced UID %s, ignoring.", v);
+ else
+ unit_ref_uid_gid(u, uid, GID_INVALID);
+
+ continue;
+
+ } else if (streq(l, "ref-gid")) {
+ gid_t gid;
+
+ r = parse_gid(v, &gid);
+ if (r < 0)
+ log_unit_debug(u, "Failed to parse referenced GID %s, ignoring.", v);
+ else
+ unit_ref_uid_gid(u, UID_INVALID, gid);
+
+ continue;
}
if (unit_can_serialize(u)) {
@@ -3310,6 +3340,7 @@ int unit_patch_contexts(Unit *u) {
}
ec->private_tmp = true;
+ ec->remove_ipc = true;
}
}
@@ -3932,3 +3963,144 @@ pid_t unit_main_pid(Unit *u) {
return 0;
}
+
+static void unit_unref_uid_internal(
+ Unit *u,
+ uid_t *ref_uid,
+ bool destroy_now,
+ void (*_manager_unref_uid)(Manager *m, uid_t uid, bool destroy_now)) {
+
+ assert(u);
+ assert(ref_uid);
+ assert(_manager_unref_uid);
+
+ /* Generic implementation of both unit_unref_uid() and unit_unref_gid(), under the assumption that uid_t and
+ * gid_t are actually the same time, with the same validity rules.
+ *
+ * Drops a reference to UID/GID from a unit. */
+
+ assert_cc(sizeof(uid_t) == sizeof(gid_t));
+ assert_cc(UID_INVALID == (uid_t) GID_INVALID);
+
+ if (!uid_is_valid(*ref_uid))
+ return;
+
+ _manager_unref_uid(u->manager, *ref_uid, destroy_now);
+ *ref_uid = UID_INVALID;
+}
+
+void unit_unref_uid(Unit *u, bool destroy_now) {
+ unit_unref_uid_internal(u, &u->ref_uid, destroy_now, manager_unref_uid);
+}
+
+void unit_unref_gid(Unit *u, bool destroy_now) {
+ unit_unref_uid_internal(u, (uid_t*) &u->ref_gid, destroy_now, manager_unref_gid);
+}
+
+static int unit_ref_uid_internal(
+ Unit *u,
+ uid_t *ref_uid,
+ uid_t uid,
+ bool clean_ipc,
+ int (*_manager_ref_uid)(Manager *m, uid_t uid, bool clean_ipc)) {
+
+ int r;
+
+ assert(u);
+ assert(ref_uid);
+ assert(uid_is_valid(uid));
+ assert(_manager_ref_uid);
+
+ /* Generic implementation of both unit_ref_uid() and unit_ref_guid(), under the assumption that uid_t and gid_t
+ * are actually the same type, and have the same validity rules.
+ *
+ * Adds a reference on a specific UID/GID to this unit. Each unit referencing the same UID/GID maintains a
+ * reference so that we can destroy the UID/GID's IPC resources as soon as this is requested and the counter
+ * drops to zero. */
+
+ assert_cc(sizeof(uid_t) == sizeof(gid_t));
+ assert_cc(UID_INVALID == (uid_t) GID_INVALID);
+
+ if (*ref_uid == uid)
+ return 0;
+
+ if (uid_is_valid(*ref_uid)) /* Already set? */
+ return -EBUSY;
+
+ r = _manager_ref_uid(u->manager, uid, clean_ipc);
+ if (r < 0)
+ return r;
+
+ *ref_uid = uid;
+ return 1;
+}
+
+int unit_ref_uid(Unit *u, uid_t uid, bool clean_ipc) {
+ return unit_ref_uid_internal(u, &u->ref_uid, uid, clean_ipc, manager_ref_uid);
+}
+
+int unit_ref_gid(Unit *u, gid_t gid, bool clean_ipc) {
+ return unit_ref_uid_internal(u, (uid_t*) &u->ref_gid, (uid_t) gid, clean_ipc, manager_ref_gid);
+}
+
+static int unit_ref_uid_gid_internal(Unit *u, uid_t uid, gid_t gid, bool clean_ipc) {
+ int r = 0, q = 0;
+
+ assert(u);
+
+ /* Reference both a UID and a GID in one go. Either references both, or neither. */
+
+ if (uid_is_valid(uid)) {
+ r = unit_ref_uid(u, uid, clean_ipc);
+ if (r < 0)
+ return r;
+ }
+
+ if (gid_is_valid(gid)) {
+ q = unit_ref_gid(u, gid, clean_ipc);
+ if (q < 0) {
+ if (r > 0)
+ unit_unref_uid(u, false);
+
+ return q;
+ }
+ }
+
+ return r > 0 || q > 0;
+}
+
+int unit_ref_uid_gid(Unit *u, uid_t uid, gid_t gid) {
+ ExecContext *c;
+ int r;
+
+ assert(u);
+
+ c = unit_get_exec_context(u);
+
+ r = unit_ref_uid_gid_internal(u, uid, gid, c ? c->remove_ipc : false);
+ if (r < 0)
+ return log_unit_warning_errno(u, r, "Couldn't add UID/GID reference to unit, proceeding without: %m");
+
+ return r;
+}
+
+void unit_unref_uid_gid(Unit *u, bool destroy_now) {
+ assert(u);
+
+ unit_unref_uid(u, destroy_now);
+ unit_unref_gid(u, destroy_now);
+}
+
+void unit_notify_user_lookup(Unit *u, uid_t uid, gid_t gid) {
+ int r;
+
+ assert(u);
+
+ /* This is invoked whenever one of the forked off processes let's us know the UID/GID its user name/group names
+ * resolved to. We keep track of which UID/GID is currently assigned in order to be able to destroy its IPC
+ * objects when no service references the UID/GID anymore. */
+
+ r = unit_ref_uid_gid(u, uid, gid);
+ if (r > 0)
+ bus_unit_send_change_signal(u);
+}
diff --git a/src/core/unit.h b/src/core/unit.h
index 513ea1614c..53875653d7 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -180,6 +180,10 @@ struct Unit {
/* Make sure we never enter endless loops with the check unneeded logic, or the BindsTo= logic */
RateLimit auto_stop_ratelimit;
+ /* Reference to a specific UID/GID */
+ uid_t ref_uid;
+ gid_t ref_gid;
+
/* Cached unit file state and preset */
UnitFileState unit_file_state;
int unit_file_preset;
@@ -371,8 +375,7 @@ struct UnitVTable {
/* Called whenever a process of this unit sends us a message */
void (*notify_message)(Unit *u, pid_t pid, char **tags, FDSet *fds);
- /* Called whenever a name this Unit registered for comes or
- * goes away. */
+ /* Called whenever a name this Unit registered for comes or goes away. */
void (*bus_name_owner_change)(Unit *u, const char *name, const char *old_owner, const char *new_owner);
/* Called for each property that is being set */
@@ -621,6 +624,17 @@ int unit_fail_if_symlink(Unit *u, const char* where);
int unit_start_limit_test(Unit *u);
+void unit_unref_uid(Unit *u, bool destroy_now);
+int unit_ref_uid(Unit *u, uid_t uid, bool clean_ipc);
+
+void unit_unref_gid(Unit *u, bool destroy_now);
+int unit_ref_gid(Unit *u, gid_t gid, bool clean_ipc);
+
+int unit_ref_uid_gid(Unit *u, uid_t uid, gid_t gid);
+void unit_unref_uid_gid(Unit *u, bool destroy_now);
+
+void unit_notify_user_lookup(Unit *u, uid_t uid, gid_t gid);
+
/* Macros which append UNIT= or USER_UNIT= to the message */
#define log_unit_full(unit, level, error, ...) \
diff --git a/src/login/logind-user.c b/src/login/logind-user.c
index 63363035e7..11951aca5b 100644
--- a/src/login/logind-user.c
+++ b/src/login/logind-user.c
@@ -612,9 +612,14 @@ int user_finalize(User *u) {
if (k < 0)
r = k;
- /* Clean SysV + POSIX IPC objects */
- if (u->manager->remove_ipc) {
- k = clean_ipc(u->uid);
+ /* Clean SysV + POSIX IPC objects, but only if this is not a system user. Background: in many setups cronjobs
+ * are run in full PAM and thus logind sessions, even if the code run doesn't belong to actual users but to
+ * system components. Since enable RemoveIPC= globally for all users, we need to be a bit careful with such
+ * cases, as we shouldn't accidentally remove a system service's IPC objects while it is running, just because
+ * a cronjob running as the same user just finished. Hence: exclude system users generally from IPC clean-up,
+ * and do it only for normal users. */
+ if (u->manager->remove_ipc && u->uid > SYSTEM_UID_MAX) {
+ k = clean_ipc_by_uid(u->uid);
if (k < 0)
r = k;
}
diff --git a/src/shared/bus-unit-util.c b/src/shared/bus-unit-util.c
index f9e12e0578..ab30afb527 100644
--- a/src/shared/bus-unit-util.c
+++ b/src/shared/bus-unit-util.c
@@ -204,7 +204,7 @@ int bus_append_unit_property_assignment(sd_bus_message *m, const char *assignmen
"IgnoreSIGPIPE", "TTYVHangup", "TTYReset", "RemainAfterExit",
"PrivateTmp", "PrivateDevices", "PrivateNetwork", "PrivateUsers", "NoNewPrivileges",
"SyslogLevelPrefix", "Delegate", "RemainAfterElapse", "MemoryDenyWriteExecute",
- "RestrictRealtime", "DynamicUser")) {
+ "RestrictRealtime", "DynamicUser", "RemoveIPC")) {
r = parse_boolean(eq);
if (r < 0)
diff --git a/src/shared/clean-ipc.c b/src/shared/clean-ipc.c
index 95686348c1..64f9b94641 100644
--- a/src/shared/clean-ipc.c
+++ b/src/shared/clean-ipc.c
@@ -41,8 +41,20 @@
#include "macro.h"
#include "string-util.h"
#include "strv.h"
+#include "user-util.h"
-static int clean_sysvipc_shm(uid_t delete_uid) {
+static bool match_uid_gid(uid_t subject_uid, gid_t subject_gid, uid_t delete_uid, gid_t delete_gid) {
+
+ if (uid_is_valid(delete_uid) && subject_uid == delete_uid)
+ return true;
+
+ if (gid_is_valid(delete_gid) && subject_gid == delete_gid)
+ return true;
+
+ return false;
+}
+
+static int clean_sysvipc_shm(uid_t delete_uid, gid_t delete_gid) {
_cleanup_fclose_ FILE *f = NULL;
char line[LINE_MAX];
bool first = true;
@@ -77,7 +89,7 @@ static int clean_sysvipc_shm(uid_t delete_uid) {
if (n_attached > 0)
continue;
- if (uid != delete_uid)
+ if (!match_uid_gid(uid, gid, delete_uid, delete_gid))
continue;
if (shmctl(shmid, IPC_RMID, NULL) < 0) {
@@ -98,7 +110,7 @@ fail:
return log_warning_errno(errno, "Failed to read /proc/sysvipc/shm: %m");
}
-static int clean_sysvipc_sem(uid_t delete_uid) {
+static int clean_sysvipc_sem(uid_t delete_uid, gid_t delete_gid) {
_cleanup_fclose_ FILE *f = NULL;
char line[LINE_MAX];
bool first = true;
@@ -128,7 +140,7 @@ static int clean_sysvipc_sem(uid_t delete_uid) {
&semid, &uid, &gid, &cuid, &cgid) != 5)
continue;
- if (uid != delete_uid)
+ if (!match_uid_gid(uid, gid, delete_uid, delete_gid))
continue;
if (semctl(semid, 0, IPC_RMID) < 0) {
@@ -149,7 +161,7 @@ fail:
return log_warning_errno(errno, "Failed to read /proc/sysvipc/sem: %m");
}
-static int clean_sysvipc_msg(uid_t delete_uid) {
+static int clean_sysvipc_msg(uid_t delete_uid, gid_t delete_gid) {
_cleanup_fclose_ FILE *f = NULL;
char line[LINE_MAX];
bool first = true;
@@ -180,7 +192,7 @@ static int clean_sysvipc_msg(uid_t delete_uid) {
&msgid, &cpid, &lpid, &uid, &gid, &cuid, &cgid) != 7)
continue;
- if (uid != delete_uid)
+ if (!match_uid_gid(uid, gid, delete_uid, delete_gid))
continue;
if (msgctl(msgid, IPC_RMID, NULL) < 0) {
@@ -201,7 +213,7 @@ fail:
return log_warning_errno(errno, "Failed to read /proc/sysvipc/msg: %m");
}
-static int clean_posix_shm_internal(DIR *dir, uid_t uid) {
+static int clean_posix_shm_internal(DIR *dir, uid_t uid, gid_t gid) {
struct dirent *de;
int ret = 0, r;
@@ -221,7 +233,7 @@ static int clean_posix_shm_internal(DIR *dir, uid_t uid) {
continue;
}
- if (st.st_uid != uid)
+ if (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
continue;
if (S_ISDIR(st.st_mode)) {
@@ -232,7 +244,7 @@ static int clean_posix_shm_internal(DIR *dir, uid_t uid) {
if (errno != ENOENT)
ret = log_warning_errno(errno, "Failed to enter shared memory directory %s: %m", de->d_name);
} else {
- r = clean_posix_shm_internal(kid, uid);
+ r = clean_posix_shm_internal(kid, uid, gid);
if (r < 0)
ret = r;
}
@@ -262,7 +274,7 @@ fail:
return log_warning_errno(errno, "Failed to read /dev/shm: %m");
}
-static int clean_posix_shm(uid_t uid) {
+static int clean_posix_shm(uid_t uid, gid_t gid) {
_cleanup_closedir_ DIR *dir = NULL;
dir = opendir("/dev/shm");
@@ -273,10 +285,10 @@ static int clean_posix_shm(uid_t uid) {
return log_warning_errno(errno, "Failed to open /dev/shm: %m");
}
- return clean_posix_shm_internal(dir, uid);
+ return clean_posix_shm_internal(dir, uid, gid);
}
-static int clean_posix_mq(uid_t uid) {
+static int clean_posix_mq(uid_t uid, gid_t gid) {
_cleanup_closedir_ DIR *dir = NULL;
struct dirent *de;
int ret = 0;
@@ -306,7 +318,7 @@ static int clean_posix_mq(uid_t uid) {
continue;
}
- if (st.st_uid != uid)
+ if (!match_uid_gid(st.st_uid, st.st_gid, uid, gid))
continue;
fn[0] = '/';
@@ -328,32 +340,44 @@ fail:
return log_warning_errno(errno, "Failed to read /dev/mqueue: %m");
}
-int clean_ipc(uid_t uid) {
+int clean_ipc(uid_t uid, gid_t gid) {
int ret = 0, r;
- /* Refuse to clean IPC of the root and system users */
- if (uid <= SYSTEM_UID_MAX)
+ /* Anything to do? */
+ if (!uid_is_valid(uid) && !gid_is_valid(gid))
return 0;
- r = clean_sysvipc_shm(uid);
+ /* Refuse to clean IPC of the root user */
+ if (uid == 0 && gid == 0)
+ return 0;
+
+ r = clean_sysvipc_shm(uid, gid);
if (r < 0)
ret = r;
- r = clean_sysvipc_sem(uid);
+ r = clean_sysvipc_sem(uid, gid);
if (r < 0)
ret = r;
- r = clean_sysvipc_msg(uid);
+ r = clean_sysvipc_msg(uid, gid);
if (r < 0)
ret = r;
- r = clean_posix_shm(uid);
+ r = clean_posix_shm(uid, gid);
if (r < 0)
ret = r;
- r = clean_posix_mq(uid);
+ r = clean_posix_mq(uid, gid);
if (r < 0)
ret = r;
return ret;
}
+
+int clean_ipc_by_uid(uid_t uid) {
+ return clean_ipc(uid, GID_INVALID);
+}
+
+int clean_ipc_by_gid(gid_t gid) {
+ return clean_ipc(UID_INVALID, gid);
+}
diff --git a/src/shared/clean-ipc.h b/src/shared/clean-ipc.h
index 44a83afcf7..6ca57f44fd 100644
--- a/src/shared/clean-ipc.h
+++ b/src/shared/clean-ipc.h
@@ -21,4 +21,6 @@
#include <sys/types.h>
-int clean_ipc(uid_t uid);
+int clean_ipc(uid_t uid, gid_t gid);
+int clean_ipc_by_uid(uid_t uid);
+int clean_ipc_by_gid(gid_t gid);
diff --git a/src/test/test-ipcrm.c b/src/test/test-ipcrm.c
index c5bcaf47bb..551eba7215 100644
--- a/src/test/test-ipcrm.c
+++ b/src/test/test-ipcrm.c
@@ -32,5 +32,5 @@ int main(int argc, char *argv[]) {
return EXIT_FAILURE;
}
- return clean_ipc(uid) < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+ return clean_ipc_by_uid(uid) < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-07-03 04:58:43 +0000