chiark / gitweb /
sd-bus: follow kdbus changes (ABI break)
[elogind.git] / src / libsystemd / sd-bus / bus-kernel.c
index 0927d82d7a7dbb6b94cf38e23dc75f9f555fd9b5..3a809e4aa625aff5f5bdcce5c89315b24046dd3b 100644 (file)
@@ -32,6 +32,8 @@
 #include "util.h"
 #include "strv.h"
 #include "memfd-util.h"
+#include "cgroup-util.h"
+#include "fileio.h"
 
 #include "bus-internal.h"
 #include "bus-message.h"
@@ -39,7 +41,6 @@
 #include "bus-bloom.h"
 #include "bus-util.h"
 #include "bus-label.h"
-#include "cgroup-util.h"
 
 #define UNIQUE_NAME_MAX (3+DECIMAL_STR_MAX(uint64_t))
 
@@ -134,6 +135,32 @@ static void append_fds(struct kdbus_item **d, const int fds[], unsigned n_fds) {
         *d = (struct kdbus_item *) ((uint8_t*) *d + (*d)->size);
 }
 
+static void add_bloom_arg(void *data, size_t size, unsigned n_hash, unsigned i, const char *t) {
+        char buf[sizeof("arg")-1 + 2 + sizeof("-slash-prefix")];
+        char *e;
+
+        assert(data);
+        assert(size > 0);
+        assert(i < 64);
+        assert(t);
+
+        e = stpcpy(buf, "arg");
+        if (i < 10)
+                *(e++) = '0' + (char) i;
+        else {
+                *(e++) = '0' + (char) (i / 10);
+                *(e++) = '0' + (char) (i % 10);
+        }
+
+        *e = 0;
+        bloom_add_pair(data, size, n_hash, buf, t);
+
+        strcpy(e, "-dot-prefix");
+        bloom_add_prefixes(data, size, n_hash, buf, t, '.');
+        strcpy(e, "-slash-prefix");
+        bloom_add_prefixes(data, size, n_hash, buf, t, '/');
+}
+
 static int bus_message_setup_bloom(sd_bus_message *m, struct kdbus_bloom_filter *bloom) {
         void *data;
         unsigned i;
@@ -163,39 +190,42 @@ static int bus_message_setup_bloom(sd_bus_message *m, struct kdbus_bloom_filter
                 return r;
 
         for (i = 0; i < 64; i++) {
+                const char *t, *contents;
                 char type;
-                const char *t;
-                char buf[sizeof("arg")-1 + 2 + sizeof("-slash-prefix")];
-                char *e;
 
-                r = sd_bus_message_peek_type(m, &type, NULL);
+                r = sd_bus_message_peek_type(m, &type, &contents);
                 if (r < 0)
                         return r;
 
-                if (type != SD_BUS_TYPE_STRING &&
-                    type != SD_BUS_TYPE_OBJECT_PATH &&
-                    type != SD_BUS_TYPE_SIGNATURE)
-                        break;
+                if (IN_SET(type, SD_BUS_TYPE_STRING, SD_BUS_TYPE_OBJECT_PATH, SD_BUS_TYPE_SIGNATURE)) {
 
-                r = sd_bus_message_read_basic(m, type, &t);
-                if (r < 0)
-                        return r;
+                        /* The bloom filter includes simple strings of any kind */
+                        r = sd_bus_message_read_basic(m, type, &t);
+                        if (r < 0)
+                                return r;
 
-                e = stpcpy(buf, "arg");
-                if (i < 10)
-                        *(e++) = '0' + (char) i;
-                else {
-                        *(e++) = '0' + (char) (i / 10);
-                        *(e++) = '0' + (char) (i % 10);
-                }
+                        add_bloom_arg(data, m->bus->bloom_size, m->bus->bloom_n_hash, i, t);
+                } if (type == SD_BUS_TYPE_ARRAY && STR_IN_SET(contents, "s", "o", "g")) {
 
-                *e = 0;
-                bloom_add_pair(data, m->bus->bloom_size, m->bus->bloom_n_hash, buf, t);
+                        /* As well as array of simple strings of any kinds */
+                        r = sd_bus_message_enter_container(m, type, contents);
+                        if (r < 0)
+                                return r;
+
+                        while ((r = sd_bus_message_read_basic(m, contents[0], &t)) > 0)
+                                add_bloom_arg(data, m->bus->bloom_size, m->bus->bloom_n_hash, i, t);
+                        if (r < 0)
+                                return r;
 
-                strcpy(e, "-dot-prefix");
-                bloom_add_prefixes(data, m->bus->bloom_size, m->bus->bloom_n_hash, buf, t, '.');
-                strcpy(e, "-slash-prefix");
-                bloom_add_prefixes(data, m->bus->bloom_size, m->bus->bloom_n_hash, buf, t, '/');
+                        r = sd_bus_message_exit_container(m);
+                        if (r < 0)
+                                return r;
+
+                } else
+                        /* Stop adding to bloom filter as soon as we
+                         * run into the first argument we cannot add
+                         * to it. */
+                        break;
         }
 
         return 0;
@@ -268,23 +298,22 @@ static int bus_message_setup_kmsg(sd_bus *b, sd_bus_message *m) {
                 ((m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED) ? 0 : KDBUS_MSG_FLAGS_EXPECT_REPLY) |
                 ((m->header->flags & BUS_MESSAGE_NO_AUTO_START) ? KDBUS_MSG_FLAGS_NO_AUTO_START : 0);
 
-        if (well_known) {
+        if (well_known)
                 /* verify_destination_id will usually be 0, which makes the kernel driver only look
                  * at the provided well-known name. Otherwise, the kernel will make sure the provided
                  * destination id matches the owner of the provided weel-known-name, and fail if they
                  * differ. Currently, this is only needed for bus-proxyd. */
                 m->kdbus->dst_id = m->verify_destination_id;
-        } else {
+        else
                 m->kdbus->dst_id = destination ? unique : KDBUS_DST_ID_BROADCAST;
-        }
 
         m->kdbus->payload_type = KDBUS_PAYLOAD_DBUS;
         m->kdbus->cookie = (uint64_t) m->header->serial;
         m->kdbus->priority = m->priority;
 
-        if (m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED) {
+        if (m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED)
                 m->kdbus->cookie_reply = m->reply_cookie;
-        else {
+        else {
                 struct timespec now;
 
                 assert_se(clock_gettime(CLOCK_MONOTONIC_COARSE, &now) == 0);
@@ -349,6 +378,15 @@ fail:
         return r;
 }
 
+static void bus_message_set_sender_driver(sd_bus *bus, sd_bus_message *m) {
+        assert(bus);
+        assert(m);
+
+        m->sender = m->creds.unique_name = (char*) "org.freedesktop.DBus";
+        m->creds.well_known_names_driver = true;
+        m->creds.mask |= (SD_BUS_CREDS_UNIQUE_NAME|SD_BUS_CREDS_WELL_KNOWN_NAMES) & bus->creds_mask;
+}
+
 static void unset_memfds(struct sd_bus_message *m) {
         struct bus_body_part *part;
         unsigned i;
@@ -384,7 +422,7 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
 
                 case KDBUS_ITEM_PAYLOAD_OFF:
                         if (!h) {
-                                h = (struct bus_header *)((uint8_t *)k + d->vec.offset);
+                                h = (struct bus_header *)((uint8_t *)bus->kdbus_buffer + d->vec.offset);
 
                                 if (!bus_header_is_complete(h, d->vec.size))
                                         return -EBADMSG;
@@ -476,11 +514,11 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
 
                                 if (idx >= begin_body) {
                                         if (!part->is_zero)
-                                                part->data = (uint8_t *)k + d->vec.offset;
+                                                part->data = (uint8_t *)bus->kdbus_buffer + d->vec.offset;
                                         part->size = d->vec.size;
                                 } else {
                                         if (!part->is_zero)
-                                                part->data = (uint8_t *)k + d->vec.offset + (begin_body - idx);
+                                                part->data = (uint8_t *)bus->kdbus_buffer + d->vec.offset + (begin_body - idx);
                                         part->size = d->vec.size - (begin_body - idx);
                                 }
 
@@ -542,42 +580,42 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
 
                         /* EUID/SUID/FSUID/EGID/SGID/FSGID might be missing too (see above). */
 
-                        if ((uid_t) d->creds.uid != (uid_t) -1) {
+                        if ((uid_t) d->creds.uid != UID_INVALID) {
                                 m->creds.uid = (uid_t) d->creds.uid;
                                 m->creds.mask |= SD_BUS_CREDS_UID & bus->creds_mask;
                         }
 
-                        if ((uid_t) d->creds.euid != (uid_t) -1) {
+                        if ((uid_t) d->creds.euid != UID_INVALID) {
                                 m->creds.euid = (uid_t) d->creds.euid;
                                 m->creds.mask |= SD_BUS_CREDS_EUID & bus->creds_mask;
                         }
 
-                        if ((uid_t) d->creds.suid != (uid_t) -1) {
+                        if ((uid_t) d->creds.suid != UID_INVALID) {
                                 m->creds.suid = (uid_t) d->creds.suid;
                                 m->creds.mask |= SD_BUS_CREDS_SUID & bus->creds_mask;
                         }
 
-                        if ((uid_t) d->creds.fsuid != (uid_t) -1) {
+                        if ((uid_t) d->creds.fsuid != UID_INVALID) {
                                 m->creds.fsuid = (uid_t) d->creds.fsuid;
                                 m->creds.mask |= SD_BUS_CREDS_FSUID & bus->creds_mask;
                         }
 
-                        if ((gid_t) d->creds.gid != (gid_t) -1) {
+                        if ((gid_t) d->creds.gid != GID_INVALID) {
                                 m->creds.gid = (gid_t) d->creds.gid;
                                 m->creds.mask |= SD_BUS_CREDS_GID & bus->creds_mask;
                         }
 
-                        if ((gid_t) d->creds.egid != (gid_t) -1) {
+                        if ((gid_t) d->creds.egid != GID_INVALID) {
                                 m->creds.egid = (gid_t) d->creds.egid;
                                 m->creds.mask |= SD_BUS_CREDS_EGID & bus->creds_mask;
                         }
 
-                        if ((gid_t) d->creds.sgid != (gid_t) -1) {
+                        if ((gid_t) d->creds.sgid != GID_INVALID) {
                                 m->creds.sgid = (gid_t) d->creds.sgid;
                                 m->creds.mask |= SD_BUS_CREDS_SGID & bus->creds_mask;
                         }
 
-                        if ((gid_t) d->creds.fsgid != (gid_t) -1) {
+                        if ((gid_t) d->creds.fsgid != GID_INVALID) {
                                 m->creds.fsgid = (gid_t) d->creds.fsgid;
                                 m->creds.mask |= SD_BUS_CREDS_FSGID & bus->creds_mask;
                         }
@@ -633,7 +671,7 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
                                 m->creds.mask |= SD_BUS_CREDS_AUDIT_SESSION_ID & bus->creds_mask;
                         }
 
-                        if ((uid_t) d->audit.loginuid != (uid_t) -1) {
+                        if ((uid_t) d->audit.loginuid != UID_INVALID) {
                                 m->creds.audit_login_uid = (uid_t) d->audit.loginuid;
                                 m->creds.mask |= SD_BUS_CREDS_AUDIT_LOGIN_UID & bus->creds_mask;
                         }
@@ -661,9 +699,23 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
                         }
 
                         if (bus->creds_mask & SD_BUS_CREDS_WELL_KNOWN_NAMES) {
-                                r = strv_extend(&m->creds.well_known_names, d->name.name);
-                                if (r < 0)
+                                char **wkn;
+                                size_t n;
+
+                                /* We just extend the array here, but
+                                 * do not allocate the strings inside
+                                 * of it, instead we just point to our
+                                 * buffer directly. */
+                                n = strv_length(m->creds.well_known_names);
+                                wkn = realloc(m->creds.well_known_names, (n + 2) * sizeof(char*));
+                                if (!wkn) {
+                                        r = -ENOMEM;
                                         goto fail;
+                                }
+
+                                wkn[n] = d->name.name;
+                                wkn[n+1] = NULL;
+                                m->creds.well_known_names = wkn;
 
                                 m->creds.mask |= SD_BUS_CREDS_WELL_KNOWN_NAMES;
                         }
@@ -677,21 +729,10 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
                 case KDBUS_ITEM_AUXGROUPS:
 
                         if (bus->creds_mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS) {
-                                size_t i, n;
-                                uid_t *u;
-                                n = (d->size - offsetof(struct kdbus_item, data64)) / sizeof(uint64_t);
-                                u = new(uid_t, n);
-                                if (!u) {
-                                        r = -ENOMEM;
-                                        goto fail;
-                                }
-
-                                for (i = 0; i < n; i++)
-                                        u[i] = (uid_t) d->data64[i];
-
-                                m->creds.supplementary_gids = u;
-                                m->creds.n_supplementary_gids = n;
+                                assert_cc(sizeof(gid_t) == sizeof(uint32_t));
 
+                                m->creds.n_supplementary_gids = (d->size - offsetof(struct kdbus_item, data32)) / sizeof(uint32_t);
+                                m->creds.supplementary_gids = (gid_t*) d->data32;
                                 m->creds.mask |= SD_BUS_CREDS_SUPPLEMENTARY_GIDS;
                         }
 
@@ -706,13 +747,45 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) {
                 }
         }
 
+        /* If we requested the list of well-known names to be appended
+         * and the sender had none no item for it will be
+         * attached. However, this does *not* mean that we the kernel
+         * didn't want to provide this information to us. Hence, let's
+         * explicitly mark this information as available if it was
+         * requested. */
+        m->creds.mask |= bus->creds_mask & SD_BUS_CREDS_WELL_KNOWN_NAMES;
+
         r = bus_message_parse_fields(m);
         if (r < 0)
                 goto fail;
 
+        /* Refuse messages if kdbus and dbus1 cookie doesn't match up */
+        if ((uint64_t) m->header->serial != k->cookie) {
+                r = -EBADMSG;
+                goto fail;
+        }
+
+        /* Refuse messages where the reply flag doesn't match up */
+        if (!(m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED) != !!(k->flags & KDBUS_MSG_FLAGS_EXPECT_REPLY)) {
+                r = -EBADMSG;
+                goto fail;
+        }
+
+        /* Refuse reply messages where the reply cookie doesn't match up */
+        if ((m->header->flags & BUS_MESSAGE_NO_REPLY_EXPECTED) && m->reply_cookie != k->cookie_reply) {
+                r = -EBADMSG;
+                goto fail;
+        }
+
+        /* Refuse messages where the autostart flag doesn't match up */
+        if (!(m->header->flags & BUS_MESSAGE_NO_AUTO_START) != !(k->flags & KDBUS_MSG_FLAGS_NO_AUTO_START)) {
+                r = -EBADMSG;
+                goto fail;
+        }
+
         /* Override information from the user header with data from the kernel */
         if (k->src_id == KDBUS_SRC_ID_KERNEL)
-                m->sender = m->creds.unique_name = (char*) "org.freedesktop.DBus";
+                bus_message_set_sender_driver(bus, m);
         else {
                 snprintf(m->sender_buffer, sizeof(m->sender_buffer), ":1.%llu", (unsigned long long) k->src_id);
                 m->sender = m->creds.unique_name = m->sender_buffer;
@@ -910,24 +983,37 @@ int bus_kernel_connect(sd_bus *b) {
         return bus_kernel_take_fd(b);
 }
 
+int bus_kernel_cmd_free(sd_bus *bus, uint64_t offset) {
+        struct kdbus_cmd_free cmd = {
+                .flags = 0,
+                .offset = offset,
+        };
+        int r;
+
+        assert(bus);
+        assert(bus->is_kernel);
+
+        r = ioctl(bus->input_fd, KDBUS_CMD_FREE, &cmd);
+        if (r < 0)
+                return -errno;
+
+        return 0;
+}
+
 static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) {
-        struct kdbus_cmd_free cmd = {};
         struct kdbus_item *d;
 
         assert(bus);
         assert(k);
 
-        cmd.offset = (uint8_t *)k - (uint8_t *)bus->kdbus_buffer;
-
         KDBUS_ITEM_FOREACH(d, k, items) {
-
                 if (d->type == KDBUS_ITEM_FDS)
                         close_many(d->fds, (d->size - offsetof(struct kdbus_item, fds)) / sizeof(int));
                 else if (d->type == KDBUS_ITEM_PAYLOAD_MEMFD)
                         safe_close(d->memfd.fd);
         }
 
-        (void) ioctl(bus->input_fd, KDBUS_CMD_FREE, &cmd);
+        bus_kernel_cmd_free(bus, (uint8_t*) k - (uint8_t*) bus->kdbus_buffer);
 }
 
 int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m, bool hint_sync_call) {
@@ -1015,7 +1101,7 @@ int bus_kernel_write_message(sd_bus *bus, sd_bus_message *m, bool hint_sync_call
 
                                 /* Anybody can send us invalid messages, let's just drop them. */
                                 if (r == -EBADMSG || r == -EPROTOTYPE)
-                                        log_debug("Ignoring invalid message: %s", strerror(-r));
+                                        log_debug_errno(r, "Ignoring invalid message: %m");
                                 else
                                         return r;
                         }
@@ -1047,7 +1133,7 @@ static int push_name_owner_changed(sd_bus *bus, const char *name, const char *ol
         if (r < 0)
                 return r;
 
-        m->sender = "org.freedesktop.DBus";
+        bus_message_set_sender_driver(bus, m);
 
         r = bus_seal_synthetic_message(bus, m);
         if (r < 0)
@@ -1116,7 +1202,7 @@ static int translate_reply(sd_bus *bus, struct kdbus_msg *k, struct kdbus_item *
         if (r < 0)
                 return r;
 
-        m->sender = "org.freedesktop.DBus";
+        bus_message_set_sender_driver(bus, m);
 
         r = bus_seal_synthetic_message(bus, m);
         if (r < 0)
@@ -1185,6 +1271,11 @@ int bus_kernel_read_message(sd_bus *bus, bool hint_priority, int64_t priority) {
                 if (errno == EAGAIN)
                         return 0;
 
+                if (errno == EOVERFLOW) {
+                        log_debug("%s: kdbus reports %" PRIu64 " dropped broadcast messages, ignoring.", strna(bus->description), (uint64_t) recv.dropped_msgs);
+                        return 0;
+                }
+
                 return -errno;
         }
 
@@ -1194,7 +1285,7 @@ int bus_kernel_read_message(sd_bus *bus, bool hint_priority, int64_t priority) {
 
                 /* Anybody can send us invalid messages, let's just drop them. */
                 if (r == -EBADMSG || r == -EPROTOTYPE) {
-                        log_debug("Ignoring invalid message: %s", strerror(-r));
+                        log_debug_errno(r, "Ignoring invalid message: %m");
                         r = 0;
                 }
 
@@ -1308,11 +1399,9 @@ void bus_kernel_flush_memfd(sd_bus *b) {
                 close_and_munmap(b->memfd_cache[i].fd, b->memfd_cache[i].address, b->memfd_cache[i].mapped);
 }
 
-int kdbus_translate_request_name_flags(uint64_t flags, uint64_t *kdbus_flags) {
+uint64_t request_name_flags_to_kdbus(uint64_t flags) {
         uint64_t f = 0;
 
-        assert(kdbus_flags);
-
         if (flags & SD_BUS_NAME_ALLOW_REPLACEMENT)
                 f |= KDBUS_NAME_ALLOW_REPLACEMENT;
 
@@ -1322,15 +1411,12 @@ int kdbus_translate_request_name_flags(uint64_t flags, uint64_t *kdbus_flags) {
         if (flags & SD_BUS_NAME_QUEUE)
                 f |= KDBUS_NAME_QUEUE;
 
-        *kdbus_flags = f;
-        return 0;
+        return f;
 }
 
-int kdbus_translate_attach_flags(uint64_t mask, uint64_t *kdbus_mask) {
+uint64_t attach_flags_to_kdbus(uint64_t mask) {
         uint64_t m = 0;
 
-        assert(kdbus_mask);
-
         if (mask & (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))
                 m |= KDBUS_ATTACH_CREDS;
@@ -1371,13 +1457,13 @@ int kdbus_translate_attach_flags(uint64_t mask, uint64_t *kdbus_mask) {
         if (mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS)
                 m |= KDBUS_ATTACH_AUXGROUPS;
 
-        *kdbus_mask = m;
-        return 0;
+        return m;
 }
 
 int bus_kernel_create_bus(const char *name, bool world, char **s) {
         struct kdbus_cmd_make *make;
         struct kdbus_item *n;
+        size_t l;
         int fd;
 
         assert(name);
@@ -1387,19 +1473,20 @@ int bus_kernel_create_bus(const char *name, bool world, char **s) {
         if (fd < 0)
                 return -errno;
 
-        make = alloca0_align(ALIGN8(offsetof(struct kdbus_cmd_make, items) +
-                                    offsetof(struct kdbus_item, data64) + sizeof(uint64_t) +
-                                    offsetof(struct kdbus_item, str) +
-                                    DECIMAL_STR_MAX(uid_t) + 1 + strlen(name) + 1),
+        l = strlen(name);
+        make = alloca0_align(offsetof(struct kdbus_cmd_make, items) +
+                             ALIGN8(offsetof(struct kdbus_item, bloom_parameter) + sizeof(struct kdbus_bloom_parameter)) +
+                             ALIGN8(offsetof(struct kdbus_item, data64) + sizeof(uint64_t)) +
+                             ALIGN8(offsetof(struct kdbus_item, str) + DECIMAL_STR_MAX(uid_t) + 1 + l + 1),
                              8);
 
         make->size = offsetof(struct kdbus_cmd_make, items);
 
+        /* Set the bloom parameters */
         n = make->items;
         n->size = offsetof(struct kdbus_item, bloom_parameter) +
                   sizeof(struct kdbus_bloom_parameter);
         n->type = KDBUS_ITEM_BLOOM_PARAMETER;
-
         n->bloom_parameter.size = DEFAULT_BLOOM_SIZE;
         n->bloom_parameter.n_hash = DEFAULT_BLOOM_N_HASH;
 
@@ -1408,6 +1495,15 @@ int bus_kernel_create_bus(const char *name, bool world, char **s) {
 
         make->size += ALIGN8(n->size);
 
+        /* The busses we create make no restrictions on what metadata
+         * peers can read from incoming messages. */
+        n = KDBUS_ITEM_NEXT(n);
+        n->type = KDBUS_ITEM_ATTACH_FLAGS_RECV;
+        n->size = offsetof(struct kdbus_item, data64) + sizeof(uint64_t);
+        n->data64[0] = _KDBUS_ATTACH_ANY;
+        make->size += ALIGN8(n->size);
+
+        /* Set the a good name */
         n = KDBUS_ITEM_NEXT(n);
         sprintf(n->str, UID_FMT "-%s", getuid(), name);
         n->size = offsetof(struct kdbus_item, str) + strlen(n->str) + 1;
@@ -1504,20 +1600,29 @@ int bus_kernel_open_bus_fd(const char *bus, char **path) {
         int fd;
         size_t len;
 
+        assert(bus);
+
         len = strlen("/sys/fs/kdbus/") + DECIMAL_STR_MAX(uid_t) + 1 + strlen(bus) + strlen("/bus") + 1;
 
         if (path) {
-                p = malloc(len);
+                p = new(char, len);
                 if (!p)
                         return -ENOMEM;
-                *path = p;
         } else
-                p = alloca(len);
+                p = newa(char, len);
+
         sprintf(p, "/sys/fs/kdbus/" UID_FMT "-%s/bus", getuid(), bus);
 
         fd = open(p, O_RDWR|O_NOCTTY|O_CLOEXEC);
-        if (fd < 0)
+        if (fd < 0) {
+                if (path)
+                        free(p);
+
                 return -errno;
+        }
+
+        if (path)
+                *path = p;
 
         return fd;
 }
@@ -1526,25 +1631,25 @@ int bus_kernel_create_endpoint(const char *bus_name, const char *ep_name, char *
         _cleanup_free_ char *path = NULL;
         struct kdbus_cmd_make *make;
         struct kdbus_item *n;
-        size_t size;
+        const char *name;
         int fd;
 
         fd = bus_kernel_open_bus_fd(bus_name, &path);
         if (fd < 0)
                 return fd;
 
-        size = ALIGN8(offsetof(struct kdbus_cmd_make, items));
-        size += ALIGN8(offsetof(struct kdbus_item, str) + strlen(ep_name) + 1);
-
-        make = alloca0_align(size, 8);
-        make->size = size;
+        make = alloca0_align(ALIGN8(offsetof(struct kdbus_cmd_make, items)) +
+                             ALIGN8(offsetof(struct kdbus_item, str) + DECIMAL_STR_MAX(uid_t) + 1 + strlen(ep_name) + 1),
+                             8);
+        make->size = ALIGN8(offsetof(struct kdbus_cmd_make, items));
         make->flags = KDBUS_MAKE_ACCESS_WORLD;
 
         n = make->items;
-
+        sprintf(n->str, UID_FMT "-%s", getuid(), ep_name);
+        n->size = offsetof(struct kdbus_item, str) + strlen(n->str) + 1;
         n->type = KDBUS_ITEM_MAKE_NAME;
-        n->size = offsetof(struct kdbus_item, str) + strlen(ep_name) + 1;
-        strcpy(n->str, ep_name);
+        make->size += ALIGN8(n->size);
+        name = n->str;
 
         if (ioctl(fd, KDBUS_CMD_ENDPOINT_MAKE, make) < 0) {
                 safe_close(fd);
@@ -1554,7 +1659,7 @@ int bus_kernel_create_endpoint(const char *bus_name, const char *ep_name, char *
         if (ep_path) {
                 char *p;
 
-                p = strjoin(dirname(path), "/", ep_name, NULL);
+                p = strjoin(dirname(path), "/", name, NULL);
                 if (!p) {
                         safe_close(fd);
                         return -ENOMEM;
@@ -1634,7 +1739,7 @@ int bus_kernel_make_starter(
         if (world_policy >= 0)
                 policy_cnt++;
 
-        size = ALIGN8(offsetof(struct kdbus_cmd_hello, items)) +
+        size = offsetof(struct kdbus_cmd_hello, items) +
                ALIGN8(offsetof(struct kdbus_item, str) + strlen(name) + 1) +
                policy_cnt * ALIGN8(offsetof(struct kdbus_item, policy_access) + sizeof(struct kdbus_policy_access));
 
@@ -1670,7 +1775,7 @@ int bus_kernel_make_starter(
                 (accept_fd ? KDBUS_HELLO_ACCEPT_FD : 0);
         hello->pool_size = KDBUS_POOL_SIZE;
         hello->attach_flags_send = _KDBUS_ATTACH_ANY;
-        hello->attach_flags_recv = _KDBUS_ATTACH_ALL;
+        hello->attach_flags_recv = _KDBUS_ATTACH_ANY;
 
         if (ioctl(fd, KDBUS_CMD_HELLO, hello) < 0)
                 return -errno;
@@ -1708,3 +1813,100 @@ int bus_kernel_drop_one(int fd) {
 
         return 0;
 }
+
+int bus_kernel_realize_attach_flags(sd_bus *bus) {
+        struct kdbus_cmd_update *update;
+        struct kdbus_item *n;
+
+        assert(bus);
+        assert(bus->is_kernel);
+
+        update = alloca0_align(offsetof(struct kdbus_cmd_update, items) +
+                               ALIGN8(offsetof(struct kdbus_item, data64) + sizeof(uint64_t)),
+                               8);
+
+        n = update->items;
+        n->type = KDBUS_ITEM_ATTACH_FLAGS_RECV;
+        n->size = offsetof(struct kdbus_item, data64) + sizeof(uint64_t);
+        n->data64[0] = bus->attach_flags;
+
+        update->size =
+                offsetof(struct kdbus_cmd_update, items) +
+                ALIGN8(n->size);
+
+        if (ioctl(bus->input_fd, KDBUS_CMD_CONN_UPDATE, update) < 0)
+                return -errno;
+
+        return 0;
+}
+
+int bus_kernel_fix_attach_mask(void) {
+        _cleanup_free_ char *mask = NULL;
+        uint64_t m = (uint64_t) -1;
+        char buf[2+16+2];
+        int r;
+
+        /* By default we don't want any kdbus metadata fields to be
+         * suppressed, hence we reset the kernel mask for it to
+         * (uint64_t) -1. This is overridable via a kernel command
+         * line option, however. */
+
+        r = get_proc_cmdline_key("systemd.kdbus_attach_flags_mask=", &mask);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to read kernel command line: %m");
+
+        if (mask) {
+                const char *p = mask;
+
+                if (startswith(p, "0x"))
+                        p += 2;
+
+                if (sscanf(p, "%" PRIx64, &m) != 1)
+                        log_warning("Couldn't parse systemd.kdbus_attach_flags_mask= kernel command line parameter.");
+        }
+
+        sprintf(buf, "0x%" PRIx64 "\n", m);
+        r = write_string_file("/sys/module/kdbus/parameters/attach_flags_mask", buf);
+        if (r < 0)
+                return log_full_errno(
+                                r == -EROFS ? LOG_DEBUG : LOG_WARNING, r,
+                                "Failed to write kdbus attach mask: %m");
+
+        return 0;
+}
+
+int bus_kernel_get_bus_name(sd_bus *bus, char **name) {
+        struct kdbus_cmd_info cmd = {
+                .size = sizeof(struct kdbus_cmd_info),
+        };
+        struct kdbus_info *info;
+        struct kdbus_item *item;
+        char *n = NULL;
+        int r;
+
+        assert(bus);
+        assert(name);
+        assert(bus->is_kernel);
+
+        r = ioctl(bus->input_fd, KDBUS_CMD_BUS_CREATOR_INFO, &cmd);
+        if (r < 0)
+                return -errno;
+
+        info = (struct kdbus_info*) ((uint8_t*) bus->kdbus_buffer + cmd.offset);
+
+        KDBUS_ITEM_FOREACH(item, info, items)
+                if (item->type == KDBUS_ITEM_MAKE_NAME) {
+                        r = free_and_strdup(&n, item->str);
+                        break;
+                }
+
+        bus_kernel_cmd_free(bus, cmd.offset);
+
+        if (r < 0)
+                return r;
+        if (!n)
+                return -EIO;
+
+        *name = n;
+        return 0;
+}