Adding upstream version 256.upstream/256

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

21 files changed, 524 insertions, 151 deletions

diff --git a/src/libsystemd/sd-bus/bus-common-errors.c b/src/libsystemd/sd-bus/bus-common-errors.c
index df26fd7..de12ec5 100644
--- a/src/libsystemd/sd-bus/bus-common-errors.c
+++ b/src/libsystemd/sd-bus/bus-common-errors.c
@@ -105,11 +105,13 @@ BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map bus_common_errors[] = {
         SD_BUS_ERROR_MAP(BUS_ERROR_TRANSFER_IN_PROGRESS,         EBUSY),
 
         SD_BUS_ERROR_MAP(BUS_ERROR_NO_PRODUCT_UUID,              EOPNOTSUPP),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NO_HARDWARE_SERIAL,           EOPNOTSUPP),
         SD_BUS_ERROR_MAP(BUS_ERROR_FILE_IS_PROTECTED,            EACCES),
         SD_BUS_ERROR_MAP(BUS_ERROR_READ_ONLY_FILESYSTEM,         EROFS),
 
         SD_BUS_ERROR_MAP(BUS_ERROR_SPEED_METER_INACTIVE,         EOPNOTSUPP),
         SD_BUS_ERROR_MAP(BUS_ERROR_UNMANAGED_INTERFACE,          EOPNOTSUPP),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NETWORK_ALREADY_RELOADING,    EBUSY),
 
         SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_HOME,                 EEXIST),
         SD_BUS_ERROR_MAP(BUS_ERROR_UID_IN_USE,                   EEXIST),
@@ -146,6 +148,7 @@ BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map bus_common_errors[] = {
         SD_BUS_ERROR_MAP(BUS_ERROR_HOME_CANT_AUTHENTICATE,       EKEYREVOKED),
         SD_BUS_ERROR_MAP(BUS_ERROR_HOME_IN_USE,                  EADDRINUSE),
         SD_BUS_ERROR_MAP(BUS_ERROR_REBALANCE_NOT_NEEDED,         EALREADY),
+        SD_BUS_ERROR_MAP(BUS_ERROR_HOME_NOT_REFERENCED,          EBADR),
 
         SD_BUS_ERROR_MAP_END
 };
diff --git a/src/libsystemd/sd-bus/bus-common-errors.h b/src/libsystemd/sd-bus/bus-common-errors.h
index 3a0eef4..94dc85d 100644
--- a/src/libsystemd/sd-bus/bus-common-errors.h
+++ b/src/libsystemd/sd-bus/bus-common-errors.h
@@ -106,11 +106,13 @@
 #define BUS_ERROR_TRANSFER_IN_PROGRESS         "org.freedesktop.import1.TransferInProgress"
 
 #define BUS_ERROR_NO_PRODUCT_UUID              "org.freedesktop.hostname1.NoProductUUID"
+#define BUS_ERROR_NO_HARDWARE_SERIAL           "org.freedesktop.hostname1.NoHardwareSerial"
 #define BUS_ERROR_FILE_IS_PROTECTED            "org.freedesktop.hostname1.FileIsProtected"
 #define BUS_ERROR_READ_ONLY_FILESYSTEM         "org.freedesktop.hostname1.ReadOnlyFilesystem"
 
 #define BUS_ERROR_SPEED_METER_INACTIVE         "org.freedesktop.network1.SpeedMeterInactive"
 #define BUS_ERROR_UNMANAGED_INTERFACE          "org.freedesktop.network1.UnmanagedInterface"
+#define BUS_ERROR_NETWORK_ALREADY_RELOADING    "org.freedesktop.network1.AlreadyReloading"
 
 #define BUS_ERROR_NO_SUCH_HOME                 "org.freedesktop.home1.NoSuchHome"
 #define BUS_ERROR_UID_IN_USE                   "org.freedesktop.home1.UIDInUse"
@@ -151,5 +153,6 @@
 #define BUS_ERROR_HOME_CANT_AUTHENTICATE       "org.freedesktop.home1.HomeCantAuthenticate"
 #define BUS_ERROR_HOME_IN_USE                  "org.freedesktop.home1.HomeInUse"
 #define BUS_ERROR_REBALANCE_NOT_NEEDED         "org.freedesktop.home1.RebalanceNotNeeded"
+#define BUS_ERROR_HOME_NOT_REFERENCED          "org.freedesktop.home1.HomeNotReferenced"
 
 BUS_ERROR_MAP_ELF_USE(bus_common_errors);
diff --git a/src/libsystemd/sd-bus/bus-container.c b/src/libsystemd/sd-bus/bus-container.c
index 4146a6e..2eca82b 100644
--- a/src/libsystemd/sd-bus/bus-container.c
+++ b/src/libsystemd/sd-bus/bus-container.c
@@ -34,7 +34,7 @@ int bus_container_connect_socket(sd_bus *b) {
                 log_debug("sd-bus: connecting bus%s%s to namespace of PID "PID_FMT"...",
                           b->description ? " " : "", strempty(b->description), b->nspid);
 
-        r = namespace_open(b->nspid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
+        r = namespace_open(b->nspid, &pidnsfd, &mntnsfd, /* ret_netns_fd = */ NULL, &usernsfd, &rootfd);
         if (r < 0)
                 return log_debug_errno(r, "Failed to open namespace of PID "PID_FMT": %m", b->nspid);
 
diff --git a/src/libsystemd/sd-bus/bus-control.c b/src/libsystemd/sd-bus/bus-control.c
index 1355e41..c420584 100644
--- a/src/libsystemd/sd-bus/bus-control.c
+++ b/src/libsystemd/sd-bus/bus-control.c
@@ -14,6 +14,7 @@
 #include "bus-internal.h"
 #include "bus-message.h"
 #include "capability-util.h"
+#include "fd-util.h"
 #include "process-util.h"
 #include "stdio-util.h"
 #include "string-util.h"
@@ -430,7 +431,6 @@ _public_ int sd_bus_get_name_creds(
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply_unique = NULL, *reply = NULL;
         _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *c = NULL;
         const char *unique;
-        pid_t pid = 0;
         int r;
 
         assert_return(bus, -EINVAL);
@@ -483,8 +483,9 @@ _public_ int sd_bus_get_name_creds(
         }
 
         if (mask != 0) {
+                bool need_pid, need_uid, need_gids, need_selinux, need_separate_calls, need_pidfd, need_augment;
                 _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
-                bool need_pid, need_uid, need_selinux, need_separate_calls;
+                _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
 
                 c = bus_creds_new();
                 if (!c)
@@ -498,20 +499,25 @@ _public_ int sd_bus_get_name_creds(
                         c->mask |= SD_BUS_CREDS_UNIQUE_NAME;
                 }
 
-                need_pid = (mask & SD_BUS_CREDS_PID) ||
-                        ((mask & SD_BUS_CREDS_AUGMENT) &&
-                         (mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
-                                  SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID|
-                                  SD_BUS_CREDS_SUPPLEMENTARY_GIDS|
-                                  SD_BUS_CREDS_COMM|SD_BUS_CREDS_EXE|SD_BUS_CREDS_CMDLINE|
-                                  SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID|
-                                  SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS|
-                                  SD_BUS_CREDS_SELINUX_CONTEXT|
-                                  SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID)));
+                need_augment =
+                        (mask & SD_BUS_CREDS_AUGMENT) &&
+                        (mask & (SD_BUS_CREDS_UID|SD_BUS_CREDS_SUID|SD_BUS_CREDS_FSUID|
+                                 SD_BUS_CREDS_GID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SGID|SD_BUS_CREDS_FSGID|
+                                 SD_BUS_CREDS_SUPPLEMENTARY_GIDS|
+                                 SD_BUS_CREDS_COMM|SD_BUS_CREDS_EXE|SD_BUS_CREDS_CMDLINE|
+                                 SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID|
+                                 SD_BUS_CREDS_EFFECTIVE_CAPS|SD_BUS_CREDS_PERMITTED_CAPS|SD_BUS_CREDS_INHERITABLE_CAPS|SD_BUS_CREDS_BOUNDING_CAPS|
+                                 SD_BUS_CREDS_SELINUX_CONTEXT|
+                                 SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID|
+                                 SD_BUS_CREDS_PIDFD));
+
+                need_pid = (mask & SD_BUS_CREDS_PID) || need_augment;
                 need_uid = mask & SD_BUS_CREDS_EUID;
+                need_gids = mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS;
                 need_selinux = mask & SD_BUS_CREDS_SELINUX_CONTEXT;
+                need_pidfd = (mask & SD_BUS_CREDS_PIDFD) || need_augment;
 
-                if (need_pid + need_uid + need_selinux > 1) {
+                if (need_pid + need_uid + need_selinux + need_pidfd + need_gids > 1) {
 
                         /* If we need more than one of the credentials, then use GetConnectionCredentials() */
 
@@ -572,7 +578,9 @@ _public_ int sd_bus_get_name_creds(
                                                 if (r < 0)
                                                         return r;
 
-                                                pid = p;
+                                                if (!pidref_is_set(&pidref))
+                                                        pidref = PIDREF_MAKE_FROM_PID(p);
+
                                                 if (mask & SD_BUS_CREDS_PID) {
                                                         c->pid = p;
                                                         c->mask |= SD_BUS_CREDS_PID;
@@ -599,6 +607,69 @@ _public_ int sd_bus_get_name_creds(
                                                 r = sd_bus_message_exit_container(reply);
                                                 if (r < 0)
                                                         return r;
+                                        } else if (need_pidfd && streq(m, "ProcessFD")) {
+                                                int fd;
+
+                                                r = sd_bus_message_read(reply, "v", "h", &fd);
+                                                if (r < 0)
+                                                        return r;
+
+                                                pidref_done(&pidref);
+                                                r = pidref_set_pidfd(&pidref, fd);
+                                                if (r < 0)
+                                                        return r;
+
+                                                if (mask & SD_BUS_CREDS_PIDFD) {
+                                                        fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
+                                                        if (fd < 0)
+                                                                return -errno;
+
+                                                        close_and_replace(c->pidfd, fd);
+                                                        c->mask |= SD_BUS_CREDS_PIDFD;
+                                                }
+                                        } else if (need_gids && streq(m, "UnixGroupIDs")) {
+
+                                                /* Note that D-Bus actually only gives us a combined list of
+                                                 * primary gid and supplementary gids. And we don't know
+                                                 * which one the primary one is. We'll take the whole shebang
+                                                 * hence and use it as the supplementary group list, and not
+                                                 * initialize the primary gid field. This is slightly
+                                                 * incorrect of course, but only slightly, as in effect if
+                                                 * the primary gid is also listed in the supplementary gid
+                                                 * it has zero effect. */
+
+                                                r = sd_bus_message_enter_container(reply, 'v', "au");
+                                                if (r < 0)
+                                                        return r;
+
+                                                r = sd_bus_message_enter_container(reply, 'a', "u");
+                                                if (r < 0)
+                                                        return r;
+
+                                                for (;;) {
+                                                        uint32_t u;
+
+                                                        r = sd_bus_message_read(reply, "u", &u);
+                                                        if (r < 0)
+                                                                return r;
+                                                        if (r == 0)
+                                                                break;
+
+                                                        if (!GREEDY_REALLOC(c->supplementary_gids, c->n_supplementary_gids+1))
+                                                                return -ENOMEM;
+
+                                                        c->supplementary_gids[c->n_supplementary_gids++] = (gid_t) u;
+                                                }
+
+                                                r = sd_bus_message_exit_container(reply);
+                                                if (r < 0)
+                                                        return r;
+
+                                                r = sd_bus_message_exit_container(reply);
+                                                if (r < 0)
+                                                        return r;
+
+                                                c->mask |= SD_BUS_CREDS_SUPPLEMENTARY_GIDS;
                                         } else {
                                                 r = sd_bus_message_skip(reply, "v");
                                                 if (r < 0)
@@ -614,7 +685,7 @@ _public_ int sd_bus_get_name_creds(
                                 if (r < 0)
                                         return r;
 
-                                if (need_pid && pid == 0)
+                                if (need_pid && !pidref_is_set(&pidref))
                                         return -EPROTO;
                         }
 
@@ -642,7 +713,9 @@ _public_ int sd_bus_get_name_creds(
                                 if (r < 0)
                                         return r;
 
-                                pid = u;
+                                if (!pidref_is_set(&pidref))
+                                        pidref = PIDREF_MAKE_FROM_PID(u);
+
                                 if (mask & SD_BUS_CREDS_PID) {
                                         c->pid = u;
                                         c->mask |= SD_BUS_CREDS_PID;
@@ -710,9 +783,11 @@ _public_ int sd_bus_get_name_creds(
                         }
                 }
 
-                r = bus_creds_add_more(c, mask, pid, 0);
-                if (r < 0 && r != -ESRCH) /* Return the error, but ignore ESRCH which just means the process is already gone */
-                        return r;
+                if (pidref_is_set(&pidref)) {
+                        r = bus_creds_add_more(c, mask, &pidref, 0);
+                        if (r < 0 && r != -ESRCH) /* Return the error, but ignore ESRCH which just means the process is already gone */
+                                return r;
+                }
         }
 
         if (creds)
@@ -765,8 +840,8 @@ not_found:
 
 _public_ int sd_bus_get_owner_creds(sd_bus *bus, uint64_t mask, sd_bus_creds **ret) {
         _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *c = NULL;
-        bool do_label, do_groups, do_sockaddr_peer;
-        pid_t pid = 0;
+        _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
+        bool do_label, do_groups, do_sockaddr_peer, do_pidfd;
         int r;
 
         assert_return(bus, -EINVAL);
@@ -786,9 +861,10 @@ _public_ int sd_bus_get_owner_creds(sd_bus *bus, uint64_t mask, sd_bus_creds **r
         do_sockaddr_peer = bus->sockaddr_size_peer >= offsetof(struct sockaddr_un, sun_path) + 1 &&
                 bus->sockaddr_peer.sa.sa_family == AF_UNIX &&
                 bus->sockaddr_peer.un.sun_path[0] == 0;
+        do_pidfd = bus->pidfd >= 0 && (mask & SD_BUS_CREDS_PIDFD);
 
         /* Avoid allocating anything if we have no chance of returning useful data */
-        if (!bus->ucred_valid && !do_label && !do_groups && !do_sockaddr_peer)
+        if (!bus->ucred_valid && !do_label && !do_groups && !do_sockaddr_peer && !do_pidfd)
                 return -ENODATA;
 
         c = bus_creds_new();
@@ -797,8 +873,10 @@ _public_ int sd_bus_get_owner_creds(sd_bus *bus, uint64_t mask, sd_bus_creds **r
 
         if (bus->ucred_valid) {
                 if (pid_is_valid(bus->ucred.pid)) {
-                        pid = c->pid = bus->ucred.pid;
+                        c->pid = bus->ucred.pid;
                         c->mask |= SD_BUS_CREDS_PID & mask;
+
+                        pidref = PIDREF_MAKE_FROM_PID(c->pid);
                 }
 
                 if (uid_is_valid(bus->ucred.uid)) {
@@ -859,7 +937,20 @@ _public_ int sd_bus_get_owner_creds(sd_bus *bus, uint64_t mask, sd_bus_creds **r
                 }
         }
 
-        r = bus_creds_add_more(c, mask, pid, 0);
+        if (do_pidfd) {
+                c->pidfd = fcntl(bus->pidfd, F_DUPFD_CLOEXEC, 3);
+                if (c->pidfd < 0)
+                        return -errno;
+
+                pidref_done(&pidref);
+                r = pidref_set_pidfd(&pidref, bus->pidfd);
+                if (r < 0)
+                        return r;
+
+                c->mask |= SD_BUS_CREDS_PIDFD;
+        }
+
+        r = bus_creds_add_more(c, mask, &pidref, 0);
         if (r < 0 && r != -ESRCH) /* If the process vanished, then don't complain, just return what we got */
                 return r;
 
diff --git a/src/libsystemd/sd-bus/bus-convenience.c b/src/libsystemd/sd-bus/bus-convenience.c
index 989e577..14d8073 100644
--- a/src/libsystemd/sd-bus/bus-convenience.c
+++ b/src/libsystemd/sd-bus/bus-convenience.c
@@ -640,8 +640,8 @@ _public_ int sd_bus_set_property(
 }
 
 _public_ int sd_bus_query_sender_creds(sd_bus_message *call, uint64_t mask, sd_bus_creds **ret) {
+        uint64_t missing;
         sd_bus_creds *c;
-        int r;
 
         assert_return(call, -EINVAL);
         assert_return(call->sealed, -EPERM);
@@ -653,36 +653,22 @@ _public_ int sd_bus_query_sender_creds(sd_bus_message *call, uint64_t mask, sd_b
                 return -ENOTCONN;
 
         c = sd_bus_message_get_creds(call);
-
-        /* All data we need? */
-        if (c && (mask & ~SD_BUS_CREDS_AUGMENT & ~c->mask) == 0) {
+        if (c)
+                missing = mask & ~SD_BUS_CREDS_AUGMENT & ~c->mask;
+        else
+                missing = mask & ~SD_BUS_CREDS_AUGMENT;
+        if (missing == 0) { /* All data we need? */
                 *ret = sd_bus_creds_ref(c);
                 return 0;
         }
 
-        /* No data passed? Or not enough data passed to retrieve the missing bits? */
-        if (!c || !(c->mask & SD_BUS_CREDS_PID)) {
-                /* We couldn't read anything from the call, let's try
-                 * to get it from the sender or peer. */
-
-                if (call->sender)
-                        /* There's a sender, but the creds are missing. */
-                        return sd_bus_get_name_creds(call->bus, call->sender, mask, ret);
-                else
-                        /* There's no sender. For direct connections
-                         * the credentials of the AF_UNIX peer matter,
-                         * which may be queried via sd_bus_get_owner_creds(). */
-                        return sd_bus_get_owner_creds(call->bus, mask, ret);
-        }
-
-        r = bus_creds_extend_by_pid(c, mask, ret);
-        if (r == -ESRCH) {
-                /* Process doesn't exist anymore? propagate the few things we have */
-                *ret = sd_bus_creds_ref(c);
-                return 0;
-        }
+        /* There's a sender, use that */
+        if (call->sender && call->bus->bus_client)
+                return sd_bus_get_name_creds(call->bus, call->sender, mask, ret);
 
-        return r;
+        /* There's no sender. For direct connections the credentials of the AF_UNIX peer matter, which may be
+         * queried via sd_bus_get_owner_creds(). */
+        return sd_bus_get_owner_creds(call->bus, mask, ret);
 }
 
 _public_ int sd_bus_query_sender_privilege(sd_bus_message *call, int capability) {
diff --git a/src/libsystemd/sd-bus/bus-creds.c b/src/libsystemd/sd-bus/bus-creds.c
index c6d8caa..adbdeaa 100644
--- a/src/libsystemd/sd-bus/bus-creds.c
+++ b/src/libsystemd/sd-bus/bus-creds.c
@@ -53,6 +53,8 @@ void bus_creds_done(sd_bus_creds *c) {
                                     * below. */
 
         strv_free(c->cmdline_array);
+
+        safe_close(c->pidfd);
 }
 
 _public_ sd_bus_creds *sd_bus_creds_ref(sd_bus_creds *c) {
@@ -129,46 +131,72 @@ _public_ uint64_t sd_bus_creds_get_augmented_mask(const sd_bus_creds *c) {
 sd_bus_creds* bus_creds_new(void) {
         sd_bus_creds *c;
 
-        c = new0(sd_bus_creds, 1);
+        c = new(sd_bus_creds, 1);
         if (!c)
                 return NULL;
 
-        c->allocated = true;
-        c->n_ref = 1;
+        *c = (sd_bus_creds) {
+                .allocated = true,
+                .n_ref = 1,
+                SD_BUS_CREDS_INIT_FIELDS,
+        };
+
         return c;
 }
 
-_public_ int sd_bus_creds_new_from_pid(sd_bus_creds **ret, pid_t pid, uint64_t mask) {
+static int bus_creds_new_from_pidref(sd_bus_creds **ret, PidRef *pidref, uint64_t mask) {
         _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *c = NULL;
         int r;
 
-        assert_return(pid >= 0, -EINVAL);
         assert_return(mask <= _SD_BUS_CREDS_ALL, -EOPNOTSUPP);
         assert_return(ret, -EINVAL);
 
-        if (pid == 0)
-                pid = getpid_cached();
-
         c = bus_creds_new();
         if (!c)
                 return -ENOMEM;
 
-        r = bus_creds_add_more(c, mask | SD_BUS_CREDS_AUGMENT, pid, 0);
+        r = bus_creds_add_more(c, mask | SD_BUS_CREDS_AUGMENT, pidref, 0);
         if (r < 0)
                 return r;
 
-        /* Check if the process existed at all, in case we haven't
-         * figured that out already */
-        r = pid_is_alive(pid);
+        r = pidref_verify(pidref);
         if (r < 0)
                 return r;
-        if (r == 0)
-                return -ESRCH;
 
         *ret = TAKE_PTR(c);
         return 0;
 }
 
+_public_ int sd_bus_creds_new_from_pid(sd_bus_creds **ret, pid_t pid, uint64_t mask) {
+        _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
+        int r;
+
+        assert_return(pid >= 0, -EINVAL);
+        assert_return(mask <= _SD_BUS_CREDS_ALL, -EOPNOTSUPP);
+        assert_return(ret, -EINVAL);
+
+        r = pidref_set_pid(&pidref, pid);
+        if (r < 0)
+                return r;
+
+        return bus_creds_new_from_pidref(ret, &pidref, mask);
+}
+
+_public_ int sd_bus_creds_new_from_pidfd(sd_bus_creds **ret, int pidfd, uint64_t mask) {
+        _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
+        int r;
+
+        assert_return(mask <= _SD_BUS_CREDS_ALL, -EOPNOTSUPP);
+        assert_return(ret, -EINVAL);
+        assert_return(pidfd >= 0, -EBADF);
+
+        r = pidref_set_pidfd(&pidref, pidfd);
+        if (r < 0)
+                return r;
+
+        return bus_creds_new_from_pidref(ret, &pidref, mask);
+}
+
 _public_ int sd_bus_creds_get_uid(sd_bus_creds *c, uid_t *uid) {
         assert_return(c, -EINVAL);
         assert_return(uid, -EINVAL);
@@ -280,6 +308,23 @@ _public_ int sd_bus_creds_get_pid(sd_bus_creds *c, pid_t *pid) {
         return 0;
 }
 
+_public_ int sd_bus_creds_get_pidfd_dup(sd_bus_creds *c, int *ret_fd) {
+        _cleanup_close_ int copy = -EBADF;
+
+        assert_return(c, -EINVAL);
+        assert_return(ret_fd, -EINVAL);
+
+        if (!(c->mask & SD_BUS_CREDS_PIDFD))
+                return -ENODATA;
+
+        copy = fcntl(c->pidfd, F_DUPFD_CLOEXEC, 3);
+        if (copy < 0)
+                return -errno;
+
+        *ret_fd = TAKE_FD(copy);
+        return 0;
+}
+
 _public_ int sd_bus_creds_get_ppid(sd_bus_creds *c, pid_t *ppid) {
         assert_return(c, -EINVAL);
         assert_return(ppid, -EINVAL);
@@ -731,7 +776,7 @@ static int parse_caps(sd_bus_creds *c, unsigned offset, const char *p) {
                         return -ENOMEM;
         }
 
-        for (i = 0; i < sz; i ++) {
+        for (i = 0; i < sz; i++) {
                 uint32_t v = 0;
 
                 for (j = 0; j < 8; ++j) {
@@ -750,7 +795,8 @@ static int parse_caps(sd_bus_creds *c, unsigned offset, const char *p) {
         return 0;
 }
 
-int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
+int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, PidRef *pidref, pid_t tid) {
+        _cleanup_(pidref_done) PidRef pidref_buf = PIDREF_NULL;
         uint64_t missing;
         int r;
 
@@ -761,12 +807,26 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
                 return 0;
 
         /* Try to retrieve PID from creds if it wasn't passed to us */
-        if (pid > 0) {
-                c->pid = pid;
+        if (pidref_is_set(pidref)) {
+                if ((c->mask & SD_BUS_CREDS_PID) && c->pid != pidref->pid) /* Insist that things match if already set */
+                        return -EBUSY;
+
+                c->pid = pidref->pid;
                 c->mask |= SD_BUS_CREDS_PID;
-        } else if (c->mask & SD_BUS_CREDS_PID)
-                pid = c->pid;
-        else
+        } else if (c->mask & SD_BUS_CREDS_PIDFD) {
+                r = pidref_set_pidfd(&pidref_buf, c->pidfd);
+                if (r < 0)
+                        return r;
+
+                pidref = &pidref_buf;
+
+        } else if (c->mask & SD_BUS_CREDS_PID) {
+                r = pidref_set_pid(&pidref_buf, c->pid);
+                if (r < 0)
+                        return r;
+
+                pidref = &pidref_buf;
+        } else
                 /* Without pid we cannot do much... */
                 return 0;
 
@@ -784,6 +844,14 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
                 c->mask |= SD_BUS_CREDS_TID;
         }
 
+        if ((missing & SD_BUS_CREDS_PIDFD) && pidref->fd >= 0) {
+                c->pidfd = fcntl(pidref->fd, F_DUPFD_CLOEXEC, 3);
+                if (c->pidfd < 0)
+                        return -errno;
+
+                c->mask |= SD_BUS_CREDS_PIDFD;
+        }
+
         if (missing & (SD_BUS_CREDS_PPID |
                        SD_BUS_CREDS_UID | SD_BUS_CREDS_EUID | SD_BUS_CREDS_SUID | SD_BUS_CREDS_FSUID |
                        SD_BUS_CREDS_GID | SD_BUS_CREDS_EGID | SD_BUS_CREDS_SGID | SD_BUS_CREDS_FSGID |
@@ -794,13 +862,13 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
                 _cleanup_fclose_ FILE *f = NULL;
                 const char *p;
 
-                p = procfs_file_alloca(pid, "status");
+                p = procfs_file_alloca(pidref->pid, "status");
 
                 f = fopen(p, "re");
                 if (!f) {
                         if (errno == ENOENT)
                                 return -ESRCH;
-                        else if (!ERRNO_IS_PRIVILEGE(errno))
+                        if (!ERRNO_IS_PRIVILEGE(errno))
                                 return -errno;
                 } else {
 
@@ -958,7 +1026,7 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         if (missing & SD_BUS_CREDS_SELINUX_CONTEXT) {
                 const char *p;
 
-                p = procfs_file_alloca(pid, "attr/current");
+                p = procfs_file_alloca(pidref->pid, "attr/current");
                 r = read_one_line_file(p, &c->label);
                 if (r < 0) {
                         if (!IN_SET(r, -ENOENT, -EINVAL, -EPERM, -EACCES))
@@ -968,7 +1036,7 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         }
 
         if (missing & SD_BUS_CREDS_COMM) {
-                r = pid_get_comm(pid, &c->comm);
+                r = pid_get_comm(pidref->pid, &c->comm);
                 if (r < 0) {
                         if (!ERRNO_IS_PRIVILEGE(r))
                                 return r;
@@ -977,7 +1045,7 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         }
 
         if (missing & SD_BUS_CREDS_EXE) {
-                r = get_process_exe(pid, &c->exe);
+                r = get_process_exe(pidref->pid, &c->exe);
                 if (r == -ESRCH) {
                         /* Unfortunately we cannot really distinguish
                          * the case here where the process does not
@@ -998,7 +1066,7 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         if (missing & SD_BUS_CREDS_CMDLINE) {
                 const char *p;
 
-                p = procfs_file_alloca(pid, "cmdline");
+                p = procfs_file_alloca(pidref->pid, "cmdline");
                 r = read_full_virtual_file(p, &c->cmdline, &c->cmdline_size);
                 if (r == -ENOENT)
                         return -ESRCH;
@@ -1016,7 +1084,7 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         if (tid > 0 && (missing & SD_BUS_CREDS_TID_COMM)) {
                 _cleanup_free_ char *p = NULL;
 
-                if (asprintf(&p, "/proc/"PID_FMT"/task/"PID_FMT"/comm", pid, tid) < 0)
+                if (asprintf(&p, "/proc/"PID_FMT"/task/"PID_FMT"/comm", pidref->pid, tid) < 0)
                         return -ENOMEM;
 
                 r = read_one_line_file(p, &c->tid_comm);
@@ -1032,7 +1100,7 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         if (missing & (SD_BUS_CREDS_CGROUP|SD_BUS_CREDS_UNIT|SD_BUS_CREDS_USER_UNIT|SD_BUS_CREDS_SLICE|SD_BUS_CREDS_USER_SLICE|SD_BUS_CREDS_SESSION|SD_BUS_CREDS_OWNER_UID)) {
 
                 if (!c->cgroup) {
-                        r = cg_pid_get_path(NULL, pid, &c->cgroup);
+                        r = cg_pid_get_path(NULL, pidref->pid, &c->cgroup);
                         if (r < 0) {
                                 if (!ERRNO_IS_PRIVILEGE(r))
                                         return r;
@@ -1050,7 +1118,7 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         }
 
         if (missing & SD_BUS_CREDS_AUDIT_SESSION_ID) {
-                r = audit_session_from_pid(pid, &c->audit_session_id);
+                r = audit_session_from_pid(pidref->pid, &c->audit_session_id);
                 if (r == -ENODATA) {
                         /* ENODATA means: no audit session id assigned */
                         c->audit_session_id = AUDIT_SESSION_INVALID;
@@ -1063,7 +1131,7 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         }
 
         if (missing & SD_BUS_CREDS_AUDIT_LOGIN_UID) {
-                r = audit_loginuid_from_pid(pid, &c->audit_login_uid);
+                r = audit_loginuid_from_pid(pidref->pid, &c->audit_login_uid);
                 if (r == -ENODATA) {
                         /* ENODATA means: no audit login uid assigned */
                         c->audit_login_uid = UID_INVALID;
@@ -1076,7 +1144,7 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
         }
 
         if (missing & SD_BUS_CREDS_TTY) {
-                r = get_ctty(pid, NULL, &c->tty);
+                r = get_ctty(pidref->pid, NULL, &c->tty);
                 if (r == -ENXIO) {
                         /* ENXIO means: process has no controlling TTY */
                         c->tty = NULL;
@@ -1088,16 +1156,12 @@ int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid) {
                         c->mask |= SD_BUS_CREDS_TTY;
         }
 
-        /* In case only the exe path was to be read we cannot distinguish the case where the exe path was
-         * unreadable because the process was a kernel thread, or when the process didn't exist at
-         * all. Hence, let's do a final check, to be sure. */
-        r = pid_is_alive(pid);
+        r = pidref_verify(pidref);
         if (r < 0)
                 return r;
-        if (r == 0)
-                return -ESRCH;
 
-        if (tid > 0 && tid != pid && pid_is_unwaited(tid) == 0)
+        /* Validate tid is still valid, too */
+        if (tid > 0 && tid != pidref->pid && pid_is_unwaited(tid) == 0)
                 return -ESRCH;
 
         c->augmented = missing & c->mask;
@@ -1131,6 +1195,13 @@ int bus_creds_extend_by_pid(sd_bus_creds *c, uint64_t mask, sd_bus_creds **ret)
                 n->mask |= SD_BUS_CREDS_PID;
         }
 
+        if (c->mask & mask & SD_BUS_CREDS_PIDFD) {
+                n->pidfd = fcntl(c->pidfd, F_DUPFD_CLOEXEC, 3);
+                if (n->pidfd < 0)
+                        return -errno;
+                n->mask |= SD_BUS_CREDS_PIDFD;
+        }
+
         if (c->mask & mask & SD_BUS_CREDS_TID) {
                 n->tid = c->tid;
                 n->mask |= SD_BUS_CREDS_TID;
diff --git a/src/libsystemd/sd-bus/bus-creds.h b/src/libsystemd/sd-bus/bus-creds.h
index 7806d9e..f45de1c 100644
--- a/src/libsystemd/sd-bus/bus-creds.h
+++ b/src/libsystemd/sd-bus/bus-creds.h
@@ -5,6 +5,9 @@
 
 #include "sd-bus.h"
 
+#include "pidref.h"
+#include "user-util.h"
+
 struct sd_bus_creds {
         bool allocated;
         unsigned n_ref;
@@ -27,6 +30,7 @@ struct sd_bus_creds {
         pid_t ppid;
         pid_t pid;
         pid_t tid;
+        int pidfd;
 
         char *comm;
         char *tid_comm;
@@ -63,10 +67,22 @@ struct sd_bus_creds {
         char *description, *unescaped_description;
 };
 
+#define SD_BUS_CREDS_INIT_FIELDS        \
+        .uid = UID_INVALID,             \
+        .euid = UID_INVALID,            \
+        .suid = UID_INVALID,            \
+        .fsuid = UID_INVALID,           \
+        .gid = GID_INVALID,             \
+        .egid = GID_INVALID,            \
+        .sgid = GID_INVALID,            \
+        .fsgid = GID_INVALID,           \
+        .pidfd = -EBADF,                \
+        .audit_login_uid = UID_INVALID
+
 sd_bus_creds* bus_creds_new(void);
 
 void bus_creds_done(sd_bus_creds *c);
 
-int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, pid_t pid, pid_t tid);
+int bus_creds_add_more(sd_bus_creds *c, uint64_t mask, PidRef *pidref, pid_t tid);
 
 int bus_creds_extend_by_pid(sd_bus_creds *c, uint64_t mask, sd_bus_creds **ret);
diff --git a/src/libsystemd/sd-bus/bus-dump.c b/src/libsystemd/sd-bus/bus-dump.c
index 6d24f3b..aa46fec 100644
--- a/src/libsystemd/sd-bus/bus-dump.c
+++ b/src/libsystemd/sd-bus/bus-dump.c
@@ -355,6 +355,8 @@ int bus_creds_dump(sd_bus_creds *c, FILE *f, bool terse) {
 
         if (c->mask & SD_BUS_CREDS_PID)
                 fprintf(f, "%sPID=%s"PID_FMT"%s", prefix, color, c->pid, suffix);
+        if (c->mask & SD_BUS_CREDS_PIDFD)
+                fprintf(f, "%sPIDFD=%syes%s", prefix, color, suffix);
         if (c->mask & SD_BUS_CREDS_TID)
                 fprintf(f, "%sTID=%s"PID_FMT"%s", prefix, color, c->tid, suffix);
         if (c->mask & SD_BUS_CREDS_PPID) {
diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h
index 098a518..e0f4746 100644
--- a/src/libsystemd/sd-bus/bus-internal.h
+++ b/src/libsystemd/sd-bus/bus-internal.h
@@ -254,6 +254,9 @@ struct sd_bus {
         char *address;
         unsigned address_index;
 
+        uid_t connect_as_uid;
+        gid_t connect_as_gid;
+
         int last_connect_error;
 
         enum bus_auth auth;
@@ -269,6 +272,7 @@ struct sd_bus {
         size_t n_groups;
         union sockaddr_union sockaddr_peer;
         socklen_t sockaddr_size_peer;
+        int pidfd;
 
         uint64_t creds_mask;
 
diff --git a/src/libsystemd/sd-bus/bus-message.c b/src/libsystemd/sd-bus/bus-message.c
index ab8b068..296f450 100644
--- a/src/libsystemd/sd-bus/bus-message.c
+++ b/src/libsystemd/sd-bus/bus-message.c
@@ -373,6 +373,7 @@ static int message_from_header(
         if (!m)
                 return -ENOMEM;
 
+        m->creds = (sd_bus_creds) { SD_BUS_CREDS_INIT_FIELDS };
         m->sealed = true;
         m->header = buffer;
 
@@ -469,6 +470,7 @@ _public_ int sd_bus_message_new(
                 return -ENOMEM;
 
         t->n_ref = 1;
+        t->creds = (sd_bus_creds) { SD_BUS_CREDS_INIT_FIELDS };
         t->bus = sd_bus_ref(bus);
         t->header = (struct bus_header*) ((uint8_t*) t + ALIGN(sizeof(struct sd_bus_message)));
         t->header->endian = BUS_NATIVE_ENDIAN;
@@ -627,7 +629,7 @@ static int message_new_reply(
                         return r;
         }
 
-        t->dont_send = !!(call->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED);
+        t->dont_send = FLAGS_SET(call->header->flags, BUS_MESSAGE_NO_REPLY_EXPECTED);
         t->enforced_reply_signature = call->enforced_reply_signature;
 
         /* let's copy the sensitive flag over. Let's do that as a safety precaution to keep a transaction
diff --git a/src/libsystemd/sd-bus/bus-objects.c b/src/libsystemd/sd-bus/bus-objects.c
index c25c40f..e528987 100644
--- a/src/libsystemd/sd-bus/bus-objects.c
+++ b/src/libsystemd/sd-bus/bus-objects.c
@@ -1701,7 +1701,7 @@ static bool names_are_valid(const char *signature, const char **names, names_fla
         if ((*flags & NAMES_FIRST_PART || *flags & NAMES_SINGLE_PART) && **names != '\0')
                 *flags |= NAMES_PRESENT;
 
-        for (;*flags & NAMES_PRESENT;) {
+        while (*flags & NAMES_PRESENT) {
                 size_t l;
 
                 if (!*signature)
diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
index 5ade8e9..07179e0 100644
--- a/src/libsystemd/sd-bus/bus-socket.c
+++ b/src/libsystemd/sd-bus/bus-socket.c
@@ -217,7 +217,7 @@ static int bus_socket_auth_verify_client(sd_bus *b) {
         /* And possibly check the third line, too */
         if (b->accept_fd) {
                 l = lines[i++];
-                b->can_fds = !!memory_startswith(l, lines[i] - l, "AGREE_UNIX_FD");
+                b->can_fds = memory_startswith(l, lines[i] - l, "AGREE_UNIX_FD");
         }
 
         assert(i == n);
@@ -266,7 +266,7 @@ static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) {
         if (l % 2 != 0)
                 return 0;
 
-        r = unhexmem(p, l, (void **) &token, &len);
+        r = unhexmem_full(p, l, /* secure = */ false, (void**) &token, &len);
         if (r < 0)
                 return 0;
 
@@ -298,7 +298,7 @@ static int verify_external_token(sd_bus *b, const char *p, size_t l) {
         if (l % 2 != 0)
                 return 0;
 
-        r = unhexmem(p, l, (void**) &token, &len);
+        r = unhexmem_full(p, l, /* secure = */ false, (void**) &token, &len);
         if (r < 0)
                 return 0;
 
@@ -503,11 +503,38 @@ static int bus_socket_write_auth(sd_bus *b) {
         if (b->prefer_writev)
                 k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index);
         else {
+                CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(struct ucred))) control = {};
+
                 struct msghdr mh = {
                         .msg_iov = b->auth_iovec + b->auth_index,
                         .msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index,
                 };
 
+                if (uid_is_valid(b->connect_as_uid) || gid_is_valid(b->connect_as_gid)) {
+
+                        /* If we shall connect under some specific UID/GID, then synthesize an
+                         * SCM_CREDENTIALS record accordingly. After all we want to adopt this UID/GID both
+                         * for SO_PEERCRED (where we have to fork()) and SCM_CREDENTIALS (where we can just
+                         * fake it via sendmsg()) */
+
+                        struct ucred ucred = {
+                                .pid = getpid_cached(),
+                                .uid = uid_is_valid(b->connect_as_uid) ? b->connect_as_uid : getuid(),
+                                .gid = gid_is_valid(b->connect_as_gid) ? b->connect_as_gid : getgid(),
+                        };
+
+                        mh.msg_control = &control;
+                        mh.msg_controllen = sizeof(control);
+                        struct cmsghdr *cmsg = CMSG_FIRSTHDR(&mh);
+                        *cmsg = (struct cmsghdr) {
+                                .cmsg_level = SOL_SOCKET,
+                                .cmsg_type = SCM_CREDENTIALS,
+                                .cmsg_len = CMSG_LEN(sizeof(struct ucred)),
+                        };
+
+                        memcpy(CMSG_DATA(cmsg), &ucred, sizeof(struct ucred));
+                }
+
                 k = sendmsg(b->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL);
                 if (k < 0 && errno == ENOTSOCK) {
                         b->prefer_writev = true;
@@ -643,14 +670,20 @@ static void bus_get_peercred(sd_bus *b) {
         /* Get the SELinux context of the peer */
         r = getpeersec(b->input_fd, &b->label);
         if (r < 0 && !IN_SET(r, -EOPNOTSUPP, -ENOPROTOOPT))
-                log_debug_errno(r, "Failed to determine peer security context: %m");
+                log_debug_errno(r, "Failed to determine peer security context, ignoring: %m");
 
         /* Get the list of auxiliary groups of the peer */
         r = getpeergroups(b->input_fd, &b->groups);
         if (r >= 0)
                 b->n_groups = (size_t) r;
         else if (!IN_SET(r, -EOPNOTSUPP, -ENOPROTOOPT))
-                log_debug_errno(r, "Failed to determine peer's group list: %m");
+                log_debug_errno(r, "Failed to determine peer's group list, ignoring: %m");
+
+        r = getpeerpidfd(b->input_fd);
+        if (r < 0)
+                log_debug_errno(r, "Failed to determine peer pidfd, ignoring: %m");
+        else
+                close_and_replace(b->pidfd, r);
 
         /* Let's query the peers socket address, it might carry information such as the peer's comm or
          * description string */
@@ -943,6 +976,66 @@ static int bind_description(sd_bus *b, int fd, int family) {
         return 0;
 }
 
+static int connect_as(int fd, const struct sockaddr *sa, socklen_t salen, uid_t uid, gid_t gid) {
+        _cleanup_(close_pairp) int pfd[2] = EBADF_PAIR;
+        ssize_t n;
+        int r;
+
+        /* Shortcut if we are not supposed to drop privileges */
+        if (!uid_is_valid(uid) && !gid_is_valid(gid))
+                return RET_NERRNO(connect(fd, sa, salen));
+
+        /* This changes identity to the specified uid/gid and issues connect() as that. This is useful to
+         * make sure SO_PEERCRED reports the selected UID/GID rather than the usual one of the caller. */
+
+        if (pipe2(pfd, O_CLOEXEC) < 0)
+                return -errno;
+
+        r = safe_fork("(sd-setresuid)", FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGKILL|FORK_WAIT, /* ret_pid= */ NULL);
+        if (r < 0)
+                return r;
+        if (r == 0) {
+                /* child */
+
+                pfd[0] = safe_close(pfd[0]);
+
+                r = RET_NERRNO(setgroups(0, NULL));
+                if (r < 0)
+                        goto child_finish;
+
+                if (gid_is_valid(gid)) {
+                        r = RET_NERRNO(setresgid(gid, gid, gid));
+                        if (r < 0)
+                                goto child_finish;
+                }
+
+                if (uid_is_valid(uid)) {
+                        r = RET_NERRNO(setresuid(uid, uid, uid));
+                        if (r < 0)
+                                goto child_finish;
+                }
+
+                r = RET_NERRNO(connect(fd, sa, salen));
+                if (r < 0)
+                        goto child_finish;
+
+                r = 0;
+
+        child_finish:
+                n = write(pfd[1], &r, sizeof(r));
+                if (n != sizeof(r))
+                        _exit(EXIT_FAILURE);
+
+                _exit(EXIT_SUCCESS);
+        }
+
+        n = read(pfd[0], &r, sizeof(r));
+        if (n != sizeof(r))
+                return -EIO;
+
+        return r;
+}
+
 int bus_socket_connect(sd_bus *b) {
         bool inotify_done = false;
         int r;
@@ -974,8 +1067,9 @@ int bus_socket_connect(sd_bus *b) {
                 b->output_fd = b->input_fd;
                 bus_socket_setup(b);
 
-                if (connect(b->input_fd, &b->sockaddr.sa, b->sockaddr_size) < 0) {
-                        if (errno == EINPROGRESS) {
+                r = connect_as(b->input_fd, &b->sockaddr.sa, b->sockaddr_size, b->connect_as_uid, b->connect_as_gid);
+                if (r < 0) {
+                        if (r == -EINPROGRESS) {
 
                                 /* If we have any inotify watches open, close them now, we don't need them anymore, as
                                  * we have successfully initiated a connection */
@@ -988,7 +1082,7 @@ int bus_socket_connect(sd_bus *b) {
                                 return 1;
                         }
 
-                        if (IN_SET(errno, ENOENT, ECONNREFUSED) &&  /* ENOENT → unix socket doesn't exist at all; ECONNREFUSED → unix socket stale */
+                        if (IN_SET(r, -ENOENT, -ECONNREFUSED) &&  /* ENOENT → unix socket doesn't exist at all; ECONNREFUSED → unix socket stale */
                             b->watch_bind &&
                             b->sockaddr.sa.sa_family == AF_UNIX &&
                             b->sockaddr.un.sun_path[0] != 0) {
@@ -1016,7 +1110,7 @@ int bus_socket_connect(sd_bus *b) {
                                 inotify_done = true;
 
                         } else
-                                return -errno;
+                                return r;
                 } else
                         break;
         }
diff --git a/src/libsystemd/sd-bus/bus-track.c b/src/libsystemd/sd-bus/bus-track.c
index f9c59a1..6f6fa2d 100644
--- a/src/libsystemd/sd-bus/bus-track.c
+++ b/src/libsystemd/sd-bus/bus-track.c
@@ -69,7 +69,7 @@ static void bus_track_add_to_queue(sd_bus_track *track) {
                 return;
 
         /* still referenced? */
-        if (hashmap_size(track->names) > 0)
+        if (!hashmap_isempty(track->names))
                 return;
 
         /* Nothing to call? */
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index 8befc97..1a642cb 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -30,6 +30,7 @@
 #include "constants.h"
 #include "errno-util.h"
 #include "fd-util.h"
+#include "format-util.h"
 #include "glyph-util.h"
 #include "hexdecoct.h"
 #include "hostname-util.h"
@@ -151,6 +152,14 @@ void bus_close_inotify_fd(sd_bus *b) {
         b->n_inotify_watches = 0;
 }
 
+static void bus_close_fds(sd_bus *b) {
+        assert(b);
+
+        bus_close_io_fds(b);
+        bus_close_inotify_fd(b);
+        b->pidfd = safe_close(b->pidfd);
+}
+
 static void bus_reset_queues(sd_bus *b) {
         assert(b);
 
@@ -191,8 +200,7 @@ static sd_bus* bus_free(sd_bus *b) {
         if (b->default_bus_ptr)
                 *b->default_bus_ptr = NULL;
 
-        bus_close_io_fds(b);
-        bus_close_inotify_fd(b);
+        bus_close_fds(b);
 
         free(b->label);
         free(b->groups);
@@ -256,7 +264,10 @@ _public_ int sd_bus_new(sd_bus **ret) {
                 .n_groups = SIZE_MAX,
                 .close_on_exit = true,
                 .ucred = UCRED_INVALID,
+                .pidfd = -EBADF,
                 .runtime_scope = _RUNTIME_SCOPE_INVALID,
+                .connect_as_uid = UID_INVALID,
+                .connect_as_gid = GID_INVALID,
         };
 
         /* We guarantee that wqueue always has space for at least one entry */
@@ -321,7 +332,7 @@ _public_ int sd_bus_set_bus_client(sd_bus *bus, int b) {
         assert_return(!bus->patch_sender, -EPERM);
         assert_return(!bus_origin_changed(bus), -ECHILD);
 
-        bus->bus_client = !!b;
+        bus->bus_client = b;
         return 0;
 }
 
@@ -331,7 +342,7 @@ _public_ int sd_bus_set_monitor(sd_bus *bus, int b) {
         assert_return(bus->state == BUS_UNSET, -EPERM);
         assert_return(!bus_origin_changed(bus), -ECHILD);
 
-        bus->is_monitor = !!b;
+        bus->is_monitor = b;
         return 0;
 }
 
@@ -341,7 +352,7 @@ _public_ int sd_bus_negotiate_fds(sd_bus *bus, int b) {
         assert_return(bus->state == BUS_UNSET, -EPERM);
         assert_return(!bus_origin_changed(bus), -ECHILD);
 
-        bus->accept_fd = !!b;
+        bus->accept_fd = b;
         return 0;
 }
 
@@ -353,7 +364,7 @@ _public_ int sd_bus_negotiate_timestamp(sd_bus *bus, int b) {
 
         /* This is not actually supported by any of our transports these days, but we do honour it for synthetic
          * replies, and maybe one day classic D-Bus learns this too */
-        bus->attach_timestamp = !!b;
+        bus->attach_timestamp = b;
 
         return 0;
 }
@@ -380,7 +391,7 @@ _public_ int sd_bus_set_server(sd_bus *bus, int b, sd_id128_t server_id) {
         assert_return(bus->state == BUS_UNSET, -EPERM);
         assert_return(!bus_origin_changed(bus), -ECHILD);
 
-        bus->is_server = !!b;
+        bus->is_server = b;
         bus->server_id = server_id;
         return 0;
 }
@@ -391,7 +402,7 @@ _public_ int sd_bus_set_anonymous(sd_bus *bus, int b) {
         assert_return(bus->state == BUS_UNSET, -EPERM);
         assert_return(!bus_origin_changed(bus), -ECHILD);
 
-        bus->anonymous_auth = !!b;
+        bus->anonymous_auth = b;
         return 0;
 }
 
@@ -401,7 +412,7 @@ _public_ int sd_bus_set_trusted(sd_bus *bus, int b) {
         assert_return(bus->state == BUS_UNSET, -EPERM);
         assert_return(!bus_origin_changed(bus), -ECHILD);
 
-        bus->trusted = !!b;
+        bus->trusted = b;
         return 0;
 }
 
@@ -419,7 +430,7 @@ _public_ int sd_bus_set_allow_interactive_authorization(sd_bus *bus, int b) {
         assert_return(bus = bus_resolve(bus), -ENOPKG);
         assert_return(!bus_origin_changed(bus), -ECHILD);
 
-        bus->allow_interactive_authorization = !!b;
+        bus->allow_interactive_authorization = b;
         return 0;
 }
 
@@ -437,7 +448,7 @@ _public_ int sd_bus_set_watch_bind(sd_bus *bus, int b) {
         assert_return(bus->state == BUS_UNSET, -EPERM);
         assert_return(!bus_origin_changed(bus), -ECHILD);
 
-        bus->watch_bind = !!b;
+        bus->watch_bind = b;
         return 0;
 }
 
@@ -455,7 +466,7 @@ _public_ int sd_bus_set_connected_signal(sd_bus *bus, int b) {
         assert_return(bus->state == BUS_UNSET, -EPERM);
         assert_return(!bus_origin_changed(bus), -ECHILD);
 
-        bus->connected_signal = !!b;
+        bus->connected_signal = b;
         return 0;
 }
 
@@ -640,7 +651,7 @@ int bus_start_running(sd_bus *bus) {
 
 static int parse_address_key(const char **p, const char *key, char **value) {
         _cleanup_free_ char *r = NULL;
-        size_t l, n = 0;
+        size_t n = 0;
         const char *a;
 
         assert(p);
@@ -648,17 +659,14 @@ static int parse_address_key(const char **p, const char *key, char **value) {
         assert(value);
 
         if (key) {
-                l = strlen(key);
-                if (strncmp(*p, key, l) != 0)
-                        return 0;
-
-                if ((*p)[l] != '=')
+                a = startswith(*p, key);
+                if (!a || *a != '=')
                         return 0;
 
                 if (*value)
                         return -EINVAL;
 
-                a = *p + l + 1;
+                a++;
         } else
                 a = *p;
 
@@ -717,7 +725,7 @@ static void skip_address_key(const char **p) {
 }
 
 static int parse_unix_address(sd_bus *b, const char **p, char **guid) {
-        _cleanup_free_ char *path = NULL, *abstract = NULL;
+        _cleanup_free_ char *path = NULL, *abstract = NULL, *uids = NULL, *gids = NULL;
         size_t l;
         int r;
 
@@ -745,6 +753,18 @@ static int parse_unix_address(sd_bus *b, const char **p, char **guid) {
                 else if (r > 0)
                         continue;
 
+                r = parse_address_key(p, "uid", &uids);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
+                r = parse_address_key(p, "gid", &gids);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        continue;
+
                 skip_address_key(p);
         }
 
@@ -781,6 +801,17 @@ static int parse_unix_address(sd_bus *b, const char **p, char **guid) {
                 b->sockaddr_size = offsetof(struct sockaddr_un, sun_path) + 1 + l;
         }
 
+        if (uids) {
+                r = parse_uid(uids, &b->connect_as_uid);
+                if (r < 0)
+                        return r;
+        }
+        if (gids) {
+                r = parse_gid(gids, &b->connect_as_gid);
+                if (r < 0)
+                        return r;
+        }
+
         b->is_local = true;
 
         return 0;
@@ -1102,8 +1133,7 @@ static int bus_start_address(sd_bus *b) {
         assert(b);
 
         for (;;) {
-                bus_close_io_fds(b);
-                bus_close_inotify_fd(b);
+                bus_close_fds(b);
 
                 bus_kill_exec(b);
 
@@ -1486,9 +1516,15 @@ interpret_port_as_machine_old_syntax:
                         return -ENOMEM;
         }
 
-        a = strjoin("unixexec:path=ssh,argv1=-xT", p ? ",argv2=-p,argv3=" : "", strempty(p),
-                                ",argv", p ? "4" : "2", "=--,argv", p ? "5" : "3", "=", e,
-                                ",argv", p ? "6" : "4", "=systemd-stdio-bridge", c);
+        const char *ssh = secure_getenv("SYSTEMD_SSH") ?: "ssh";
+        _cleanup_free_ char *ssh_escaped = bus_address_escape(ssh);
+        if (!ssh_escaped)
+                return -ENOMEM;
+
+        a = strjoin("unixexec:path=", ssh_escaped, ",argv1=-xT",
+                    p ? ",argv2=-p,argv3=" : "", strempty(p),
+                    ",argv", p ? "4" : "2", "=--,argv", p ? "5" : "3", "=", e,
+                    ",argv", p ? "6" : "4", "=systemd-stdio-bridge", c);
         if (!a)
                 return -ENOMEM;
 
@@ -1668,10 +1704,7 @@ static int user_and_machine_equivalent(const char *user_and_machine) {
                 return true;
 
         /* Otherwise, we have to figure out our user id and name, and compare things with that. */
-        char buf[DECIMAL_STR_MAX(uid_t)];
-        xsprintf(buf, UID_FMT, uid);
-
-        f = startswith(user_and_machine, buf);
+        f = startswith(user_and_machine, FORMAT_UID(uid));
         if (!f) {
                 un = getusername_malloc();
                 if (!un)
@@ -1775,8 +1808,7 @@ _public_ void sd_bus_close(sd_bus *bus) {
          * the bus object and the bus may be freed */
         bus_reset_queues(bus);
 
-        bus_close_io_fds(bus);
-        bus_close_inotify_fd(bus);
+        bus_close_fds(bus);
 }
 
 _public_ sd_bus *sd_bus_close_unref(sd_bus *bus) {
@@ -4123,13 +4155,13 @@ _public_ int sd_bus_path_decode_many(const char *path, const char *path_template
 
         for (template_pos = path_template; *template_pos; ) {
                 const char *sep;
-                size_t length;
+                size_t length, path_length;
                 char *label;
 
                 /* verify everything until the next '%' matches verbatim */
                 sep = strchrnul(template_pos, '%');
                 length = sep - template_pos;
-                if (strncmp(path_pos, template_pos, length))
+                if (!strneq(path_pos, template_pos, length))
                         return 0;
 
                 path_pos += length;
@@ -4150,8 +4182,8 @@ _public_ int sd_bus_path_decode_many(const char *path, const char *path_template
 
                 /* verify the suffixes match */
                 sep = strchrnul(path_pos, '/');
-                if (sep - path_pos < (ssize_t)length ||
-                    strncmp(sep - length, template_pos, length))
+                path_length = sep - path_pos;
+                if (length > path_length || !strneq(sep - length, template_pos, length))
                         return 0;
 
                 template_pos += length; /* skip over matched label */
diff --git a/src/libsystemd/sd-bus/test-bus-chat.c b/src/libsystemd/sd-bus/test-bus-chat.c
index da1340f..d06853b 100644
--- a/src/libsystemd/sd-bus/test-bus-chat.c
+++ b/src/libsystemd/sd-bus/test-bus-chat.c
@@ -432,8 +432,7 @@ static void* client2(void *p) {
         if (r < 0)
                 log_debug("Failed to issue method call: %s", bus_error_message(&error, r));
         else {
-                log_error("Slow call unexpectedly succeed.");
-                r = -ENOANO;
+                r = log_error_errno(SYNTHETIC_ERRNO(ENOANO), "Slow call unexpectedly succeeded.");
                 goto finish;
         }
 
diff --git a/src/libsystemd/sd-bus/test-bus-cleanup.c b/src/libsystemd/sd-bus/test-bus-cleanup.c
index 3e14627..b569986 100644
--- a/src/libsystemd/sd-bus/test-bus-cleanup.c
+++ b/src/libsystemd/sd-bus/test-bus-cleanup.c
@@ -30,7 +30,7 @@ static void test_bus_fork(void) {
         r = safe_fork("(bus-fork-test)", FORK_WAIT|FORK_LOG, NULL);
         if (r == 0) {
                 assert_se(bus);
-                assert_se(sd_bus_is_ready(bus) == -ECHILD);
+                ASSERT_RETURN_EXPECTED_SE(sd_bus_is_ready(bus) == -ECHILD);
                 assert_se(sd_bus_flush_close_unref(bus) == NULL);
                 assert_se(sd_bus_close_unref(bus) == NULL);
                 assert_se(sd_bus_unref(bus) == NULL);
diff --git a/src/libsystemd/sd-bus/test-bus-creds.c b/src/libsystemd/sd-bus/test-bus-creds.c
index 13801be..7eb7a38 100644
--- a/src/libsystemd/sd-bus/test-bus-creds.c
+++ b/src/libsystemd/sd-bus/test-bus-creds.c
@@ -4,6 +4,7 @@
 
 #include "bus-dump.h"
 #include "cgroup-util.h"
+#include "errno-util.h"
 #include "tests.h"
 
 int main(int argc, char *argv[]) {
@@ -12,7 +13,7 @@ int main(int argc, char *argv[]) {
 
         test_setup_logging(LOG_DEBUG);
 
-        if (cg_unified() == -ENOMEDIUM)
+        if (IN_SET(cg_unified(), -ENOMEDIUM, -ENOENT))
                 return log_tests_skipped("/sys/fs/cgroup/ not available");
 
         r = sd_bus_creds_new_from_pid(&creds, 0, _SD_BUS_CREDS_ALL);
@@ -24,11 +25,30 @@ int main(int argc, char *argv[]) {
         creds = sd_bus_creds_unref(creds);
 
         r = sd_bus_creds_new_from_pid(&creds, 1, _SD_BUS_CREDS_ALL);
-        if (r != -EACCES) {
+        if (!ERRNO_IS_NEG_PRIVILEGE(r)) {
                 assert_se(r >= 0);
                 putchar('\n');
                 bus_creds_dump(creds, NULL, true);
         }
 
+        creds = sd_bus_creds_unref(creds);
+
+        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
+        r = sd_bus_default_system(&bus);
+        if (r < 0)
+                log_warning_errno(r, "Unable to connect to system bus, skipping rest of test.");
+        else {
+                const char *unique;
+
+                assert_se(sd_bus_get_unique_name(bus, &unique) >= 0);
+
+                r = sd_bus_get_name_creds(bus, unique, _SD_BUS_CREDS_ALL, &creds);
+                log_full_errno(r < 0 ? LOG_ERR : LOG_DEBUG, r, "sd_bus_get_name_creds: %m");
+                assert_se(r >= 0);
+
+                putchar('\n');
+                bus_creds_dump(creds, NULL, true);
+        }
+
         return 0;
 }
diff --git a/src/libsystemd/sd-bus/test-bus-error.c b/src/libsystemd/sd-bus/test-bus-error.c
index a55f3f9..91045c0 100644
--- a/src/libsystemd/sd-bus/test-bus-error.c
+++ b/src/libsystemd/sd-bus/test-bus-error.c
@@ -213,8 +213,8 @@ TEST(errno_mapping_custom) {
 
         assert_se(sd_bus_error_set(NULL, BUS_ERROR_NO_SUCH_UNIT, NULL) == -ENOENT);
 
-        assert_se(sd_bus_error_add_map(test_errors_bad1) == -EINVAL);
-        assert_se(sd_bus_error_add_map(test_errors_bad2) == -EINVAL);
+        ASSERT_RETURN_EXPECTED_SE(sd_bus_error_add_map(test_errors_bad1) == -EINVAL);
+        ASSERT_RETURN_EXPECTED_SE(sd_bus_error_add_map(test_errors_bad2) == -EINVAL);
 }
 
 TEST(sd_bus_error_set_errnof) {
diff --git a/src/libsystemd/sd-bus/test-bus-marshal.c b/src/libsystemd/sd-bus/test-bus-marshal.c
index 0044d33..92da627 100644
--- a/src/libsystemd/sd-bus/test-bus-marshal.c
+++ b/src/libsystemd/sd-bus/test-bus-marshal.c
@@ -42,8 +42,8 @@ static void test_bus_path_encode(void) {
         assert_se(sd_bus_path_decode(a, "/waldo", &b) == 0 && b == NULL);
         assert_se(sd_bus_path_decode(a, "/foo/bar", &b) > 0 && streq(b, "waldo"));
 
-        assert_se(sd_bus_path_encode("xxxx", "waldo", &c) < 0);
-        assert_se(sd_bus_path_encode("/foo/", "waldo", &c) < 0);
+        ASSERT_RETURN_EXPECTED_SE(sd_bus_path_encode("xxxx", "waldo", &c) < 0);
+        ASSERT_RETURN_EXPECTED_SE(sd_bus_path_encode("/foo/", "waldo", &c) < 0);
 
         assert_se(sd_bus_path_encode("/foo/bar", "", &c) >= 0 && streq(c, "/foo/bar/_"));
         assert_se(sd_bus_path_decode(c, "/foo/bar", &d) > 0 && streq(d, ""));
diff --git a/src/libsystemd/sd-bus/test-bus-objects.c b/src/libsystemd/sd-bus/test-bus-objects.c
index ccdd0d5..2847ba8 100644
--- a/src/libsystemd/sd-bus/test-bus-objects.c
+++ b/src/libsystemd/sd-bus/test-bus-objects.c
@@ -494,10 +494,9 @@ static int client(struct context *c) {
                         }
                         assert_se(sd_bus_message_exit_container(reply) >= 0);
 
-                        if (streq(path, "/value/a")) {
+                        if (streq(path, "/value/a"))
                                 /* ObjectManager must be here */
                                 assert_se(found_object_manager_interface);
-                        }
 
                 } else
                         assert_se(sd_bus_message_skip(reply, "a{sa{sv}}") >= 0);
diff --git a/src/libsystemd/sd-bus/test-bus-peersockaddr.c b/src/libsystemd/sd-bus/test-bus-peersockaddr.c
index 79556e8..a7bba17 100644
--- a/src/libsystemd/sd-bus/test-bus-peersockaddr.c
+++ b/src/libsystemd/sd-bus/test-bus-peersockaddr.c
@@ -5,10 +5,39 @@
 
 #include "sd-bus.h"
 
+#include "bus-dump.h"
+#include "bus-util.h"
 #include "fd-util.h"
 #include "process-util.h"
 #include "socket-util.h"
+#include "sort-util.h"
 #include "tests.h"
+#include "user-util.h"
+
+static bool gid_list_contained(const gid_t *a, size_t n, const gid_t *b, size_t m) {
+        assert_se(a || n == 0);
+        assert_se(b || m == 0);
+
+        /* Checks if every entry in a[] is also in b[] */
+
+        for (size_t i = 0; i < n; i++) {
+                size_t j;
+
+                for (j = 0; j < m; j++)
+                        if (a[i] == b[j])
+                                break;
+
+                if (j >= m)
+                        return false;
+        }
+
+        return true;
+}
+
+static bool gid_list_same(const gid_t *a, size_t n, const gid_t *b, size_t m) {
+        return gid_list_contained(a, n, b, m) &&
+                gid_list_contained(b, m, a, n);
+}
 
 static void *server(void *p) {
         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
@@ -27,11 +56,13 @@ static void *server(void *p) {
         assert_se(sd_bus_set_fd(bus, fd, fd) >= 0);
         TAKE_FD(fd);
         assert_se(sd_bus_set_server(bus, true, id) >= 0);
-        assert_se(sd_bus_negotiate_creds(bus, 1, SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_PID|SD_BUS_CREDS_COMM|SD_BUS_CREDS_DESCRIPTION) >= 0);
+        assert_se(sd_bus_negotiate_creds(bus, 1, SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_PID|SD_BUS_CREDS_COMM|SD_BUS_CREDS_DESCRIPTION|SD_BUS_CREDS_PIDFD|SD_BUS_CREDS_SUPPLEMENTARY_GIDS) >= 0);
 
         assert_se(sd_bus_start(bus) >= 0);
 
-        assert_se(sd_bus_get_owner_creds(bus, SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_PID|SD_BUS_CREDS_COMM|SD_BUS_CREDS_DESCRIPTION, &c) >= 0);
+        assert_se(sd_bus_get_owner_creds(bus, SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_PID|SD_BUS_CREDS_COMM|SD_BUS_CREDS_DESCRIPTION|SD_BUS_CREDS_PIDFD|SD_BUS_CREDS_SUPPLEMENTARY_GIDS, &c) >= 0);
+
+        bus_creds_dump(c, /* f= */ NULL, /* terse= */ false);
 
         uid_t u;
         assert_se(sd_bus_creds_get_euid(c, &u) >= 0);
@@ -45,6 +76,26 @@ static void *server(void *p) {
         assert_se(sd_bus_creds_get_pid(c, &pid) >= 0);
         assert_se(pid == getpid_cached());
 
+        int pidfd = -EBADF;
+        if (sd_bus_creds_get_pidfd_dup(c, &pidfd) >= 0) {
+                _cleanup_(pidref_done) PidRef pidref = PIDREF_NULL;
+
+                assert_se(pidref_set_pidfd_take(&pidref, pidfd) >= 0);
+                assert_se(pidref.pid == getpid_cached());
+        }
+
+        const gid_t *gl = NULL;
+        int n;
+        n = sd_bus_creds_get_supplementary_gids(c, &gl);
+
+        if (n >= 0) {
+                _cleanup_free_ gid_t *gg = NULL;
+                r = getgroups_alloc(&gg);
+                assert_se(r >= 0);
+
+                assert_se(gid_list_same(gl, n, gg, r));
+        }
+
         const char *comm;
         assert_se(sd_bus_creds_get_comm(c, &comm) >= 0);
         assert_se(pid_get_comm(0, &our_comm) >= 0);