X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=src%2Flibsystemd%2Fsd-bus%2Fbus-kernel.c;h=84fb4bdf2b4af185c8ab6f0de7523c96d5a6ce79;hp=79d29dc119798b0da25e319fdf65a9dd3d207dae;hb=1214b53c8e463ec328021e90163279ac94dd9af8;hpb=705a415f684f8e9ee19983e5859de00bbb1477cb diff --git a/src/libsystemd/sd-bus/bus-kernel.c b/src/libsystemd/sd-bus/bus-kernel.c index 79d29dc11..84fb4bdf2 100644 --- a/src/libsystemd/sd-bus/bus-kernel.c +++ b/src/libsystemd/sd-bus/bus-kernel.c @@ -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)) @@ -268,23 +269,22 @@ 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 +349,15 @@ 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; @@ -628,9 +637,15 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) { break; case KDBUS_ITEM_AUDIT: - m->creds.audit_session_id = (uint32_t) d->audit.sessionid; - m->creds.audit_login_uid = (uid_t) d->audit.loginuid; - m->creds.mask |= (SD_BUS_CREDS_AUDIT_SESSION_ID|SD_BUS_CREDS_AUDIT_LOGIN_UID) & bus->creds_mask; + if ((uint32_t) d->audit.sessionid != (uint32_t) -1) { + m->creds.audit_session_id = (uint32_t) d->audit.sessionid; + m->creds.mask |= SD_BUS_CREDS_AUDIT_SESSION_ID & bus->creds_mask; + } + + if ((uid_t) d->audit.loginuid != (uid_t) -1) { + m->creds.audit_login_uid = (uid_t) d->audit.loginuid; + m->creds.mask |= SD_BUS_CREDS_AUDIT_LOGIN_UID & bus->creds_mask; + } break; case KDBUS_ITEM_CAPS: @@ -640,19 +655,41 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) { break; case KDBUS_ITEM_DST_NAME: - if (!service_name_is_valid(d->str)) - return -EBADMSG; + if (!service_name_is_valid(d->str)) { + r = -EBADMSG; + goto fail; + } destination = d->str; break; case KDBUS_ITEM_OWNED_NAME: - if (!service_name_is_valid(d->name.name)) - return -EBADMSG; - - r = strv_extend(&m->creds.well_known_names, d->name.name); - if (r < 0) + if (!service_name_is_valid(d->name.name)) { + r = -EBADMSG; goto fail; + } + + if (bus->creds_mask & SD_BUS_CREDS_WELL_KNOWN_NAMES) { + 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; + } break; case KDBUS_ITEM_CONN_DESCRIPTION: @@ -660,6 +697,18 @@ static int bus_kernel_make_message(sd_bus *bus, struct kdbus_msg *k) { m->creds.mask |= SD_BUS_CREDS_DESCRIPTION & bus->creds_mask; break; + case KDBUS_ITEM_AUXGROUPS: + + if (bus->creds_mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS) { + 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; + } + + break; + case KDBUS_ITEM_FDS: case KDBUS_ITEM_SECLABEL: break; @@ -669,13 +718,45 @@ 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; @@ -874,13 +955,12 @@ int bus_kernel_connect(sd_bus *b) { } static void close_kdbus_msg(sd_bus *bus, struct kdbus_msg *k) { - struct kdbus_cmd_free cmd; + struct kdbus_cmd_free cmd = {}; struct kdbus_item *d; assert(bus); assert(k); - cmd.flags = 0; cmd.offset = (uint8_t *)k - (uint8_t *)bus->kdbus_buffer; KDBUS_ITEM_FOREACH(d, k, items) { @@ -1011,7 +1091,7 @@ 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) @@ -1080,7 +1160,7 @@ 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) @@ -1149,6 +1229,11 @@ 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; } @@ -1272,11 +1357,9 @@ 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; @@ -1286,15 +1369,12 @@ 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; @@ -1332,13 +1412,16 @@ int kdbus_translate_attach_flags(uint64_t mask, uint64_t *kdbus_mask) { if (mask & SD_BUS_CREDS_DESCRIPTION) m |= KDBUS_ATTACH_CONN_DESCRIPTION; - *kdbus_mask = m; - return 0; + if (mask & SD_BUS_CREDS_SUPPLEMENTARY_GIDS) + m |= KDBUS_ATTACH_AUXGROUPS; + + 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); @@ -1348,19 +1431,20 @@ 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; @@ -1369,6 +1453,15 @@ 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; @@ -1465,20 +1558,29 @@ 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; } @@ -1487,25 +1589,25 @@ 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); @@ -1515,7 +1617,7 @@ 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; @@ -1595,7 +1697,7 @@ 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)); @@ -1631,7 +1733,7 @@ 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; @@ -1669,3 +1771,64 @@ 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; +}