/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include #include "sd-bus.h" #include "sd-daemon.h" #include "alloc-util.h" #include "bus-internal.h" #include "bus-message.h" #include "bus-socket.h" #include "escape.h" #include "fd-util.h" #include "format-util.h" #include "fs-util.h" #include "hexdecoct.h" #include "io-util.h" #include "macro.h" #include "memory-util.h" #include "path-util.h" #include "process-util.h" #include "rlimit-util.h" #include "signal-util.h" #include "stdio-util.h" #include "string-util.h" #include "user-util.h" #include "utf8.h" #define SNDBUF_SIZE (8*1024*1024) static void iovec_advance(struct iovec iov[], unsigned *idx, size_t size) { while (size > 0) { struct iovec *i = iov + *idx; if (i->iov_len > size) { i->iov_base = (uint8_t*) i->iov_base + size; i->iov_len -= size; return; } size -= i->iov_len; *i = IOVEC_MAKE(NULL, 0); (*idx)++; } } static int append_iovec(sd_bus_message *m, const void *p, size_t sz) { assert(m); assert(p); assert(sz > 0); m->iovec[m->n_iovec++] = IOVEC_MAKE((void*) p, sz); return 0; } static int bus_message_setup_iovec(sd_bus_message *m) { struct bus_body_part *part; unsigned n, i; int r; assert(m); assert(m->sealed); if (m->n_iovec > 0) return 0; assert(!m->iovec); n = 1 + m->n_body_parts; if (n < ELEMENTSOF(m->iovec_fixed)) m->iovec = m->iovec_fixed; else { m->iovec = new(struct iovec, n); if (!m->iovec) { r = -ENOMEM; goto fail; } } r = append_iovec(m, m->header, BUS_MESSAGE_BODY_BEGIN(m)); if (r < 0) goto fail; MESSAGE_FOREACH_PART(part, i, m) { r = bus_body_part_map(part); if (r < 0) goto fail; r = append_iovec(m, part->data, part->size); if (r < 0) goto fail; } assert(n == m->n_iovec); return 0; fail: m->poisoned = true; return r; } bool bus_socket_auth_needs_write(sd_bus *b) { unsigned i; if (b->auth_index >= ELEMENTSOF(b->auth_iovec)) return false; for (i = b->auth_index; i < ELEMENTSOF(b->auth_iovec); i++) { struct iovec *j = b->auth_iovec + i; if (j->iov_len > 0) return true; } return false; } static int bus_socket_write_auth(sd_bus *b) { ssize_t k; assert(b); assert(b->state == BUS_AUTHENTICATING); if (!bus_socket_auth_needs_write(b)) return 0; if (b->prefer_writev) k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index); else { struct msghdr mh = { .msg_iov = b->auth_iovec + b->auth_index, .msg_iovlen = ELEMENTSOF(b->auth_iovec) - b->auth_index, }; k = sendmsg(b->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL); if (k < 0 && errno == ENOTSOCK) { b->prefer_writev = true; k = writev(b->output_fd, b->auth_iovec + b->auth_index, ELEMENTSOF(b->auth_iovec) - b->auth_index); } } if (k < 0) return ERRNO_IS_TRANSIENT(errno) ? 0 : -errno; iovec_advance(b->auth_iovec, &b->auth_index, (size_t) k); return 1; } static int bus_socket_auth_verify_client(sd_bus *b) { char *d, *e, *f, *start; sd_id128_t peer; int r; assert(b); /* * We expect three response lines: * "DATA\r\n" * "OK \r\n" * "AGREE_UNIX_FD\r\n" (optional) */ d = memmem_safe(b->rbuffer, b->rbuffer_size, "\r\n", 2); if (!d) return 0; e = memmem_safe(d + 2, b->rbuffer_size - (d - (char*) b->rbuffer) - 2, "\r\n", 2); if (!e) return 0; if (b->accept_fd) { f = memmem_safe(e + 2, b->rbuffer_size - (e - (char*) b->rbuffer) - 2, "\r\n", 2); if (!f) return 0; start = f + 2; } else { f = NULL; start = e + 2; } /* Nice! We got all the lines we need. First check the DATA line. */ if (d - (char*) b->rbuffer == 4) { if (memcmp(b->rbuffer, "DATA", 4)) return -EPERM; } else if (d - (char*) b->rbuffer == 3 + 32) { /* * Old versions of the server-side implementation of `sd-bus` replied with "OK " to * "AUTH" requests from a client, even if the "AUTH" line did not contain inlined * arguments. Therefore, we also accept "OK " here, even though it is technically the * wrong reply. We ignore the "" parameter, though, since it has no real value. */ if (memcmp(b->rbuffer, "OK ", 3)) return -EPERM; } else return -EPERM; /* Now check the OK line. */ if (e - d != 2 + 3 + 32) return -EPERM; if (memcmp(d + 2, "OK ", 3)) return -EPERM; b->auth = b->anonymous_auth ? BUS_AUTH_ANONYMOUS : BUS_AUTH_EXTERNAL; for (unsigned i = 0; i < 32; i += 2) { int x, y; x = unhexchar(d[2 + 3 + i]); y = unhexchar(d[2 + 3 + i + 1]); if (x < 0 || y < 0) return -EINVAL; peer.bytes[i/2] = ((uint8_t) x << 4 | (uint8_t) y); } if (!sd_id128_is_null(b->server_id) && !sd_id128_equal(b->server_id, peer)) return -EPERM; b->server_id = peer; /* And possibly check the third line, too */ if (f) b->can_fds = (f - e == STRLEN("\r\nAGREE_UNIX_FD")) && memcmp(e + 2, "AGREE_UNIX_FD", STRLEN("AGREE_UNIX_FD")) == 0; b->rbuffer_size -= (start - (char*) b->rbuffer); memmove(b->rbuffer, start, b->rbuffer_size); r = bus_start_running(b); if (r < 0) return r; return 1; } static bool line_equals(const char *s, size_t m, const char *line) { size_t l; l = strlen(line); if (l != m) return false; return memcmp(s, line, l) == 0; } static bool line_begins(const char *s, size_t m, const char *word) { const char *p; p = memory_startswith(s, m, word); return p && (p == (s + m) || *p == ' '); } static int verify_anonymous_token(sd_bus *b, const char *p, size_t l) { _cleanup_free_ char *token = NULL; size_t len; int r; if (!b->anonymous_auth) return 0; if (l <= 0) return 1; assert(p[0] == ' '); p++; l--; if (l % 2 != 0) return 0; r = unhexmem(p, l, (void **) &token, &len); if (r < 0) return 0; if (memchr(token, 0, len)) return 0; return !!utf8_is_valid(token); } static int verify_external_token(sd_bus *b, const char *p, size_t l) { _cleanup_free_ char *token = NULL; size_t len; uid_t u; int r; /* We don't do any real authentication here. Instead, if * the owner of this bus wanted authentication they should have * checked SO_PEERCRED before even creating the bus object. */ if (!b->anonymous_auth && !b->ucred_valid) return 0; if (l <= 0) return 1; assert(p[0] == ' '); p++; l--; if (l % 2 != 0) return 0; r = unhexmem(p, l, (void**) &token, &len); if (r < 0) return 0; if (memchr(token, 0, len)) return 0; r = parse_uid(token, &u); if (r < 0) return 0; /* We ignore the passed value if anonymous authentication is * on anyway. */ if (!b->anonymous_auth && u != b->ucred.uid) return 0; return 1; } static int bus_socket_auth_write(sd_bus *b, const char *t) { char *p; size_t l; assert(b); assert(t); /* We only make use of the first iovec */ assert(IN_SET(b->auth_index, 0, 1)); l = strlen(t); p = malloc(b->auth_iovec[0].iov_len + l); if (!p) return -ENOMEM; memcpy_safe(p, b->auth_iovec[0].iov_base, b->auth_iovec[0].iov_len); memcpy(p + b->auth_iovec[0].iov_len, t, l); b->auth_iovec[0].iov_base = p; b->auth_iovec[0].iov_len += l; free(b->auth_buffer); b->auth_buffer = p; b->auth_index = 0; return 0; } static int bus_socket_auth_write_ok(sd_bus *b) { char t[3 + 32 + 2 + 1]; assert(b); xsprintf(t, "OK " SD_ID128_FORMAT_STR "\r\n", SD_ID128_FORMAT_VAL(b->server_id)); return bus_socket_auth_write(b, t); } static int bus_socket_auth_verify_server(sd_bus *b) { char *e; const char *line; size_t l; bool processed = false; int r; assert(b); if (b->rbuffer_size < 1) return 0; /* First char must be a NUL byte */ if (*(char*) b->rbuffer != 0) return -EIO; if (b->rbuffer_size < 3) return 0; /* Begin with the first line */ if (b->auth_rbegin <= 0) b->auth_rbegin = 1; for (;;) { /* Check if line is complete */ line = (char*) b->rbuffer + b->auth_rbegin; e = memmem_safe(line, b->rbuffer_size - b->auth_rbegin, "\r\n", 2); if (!e) return processed; l = e - line; if (line_begins(line, l, "AUTH ANONYMOUS")) { r = verify_anonymous_token(b, line + strlen("AUTH ANONYMOUS"), l - strlen("AUTH ANONYMOUS")); if (r < 0) return r; if (r == 0) r = bus_socket_auth_write(b, "REJECTED\r\n"); else { b->auth = BUS_AUTH_ANONYMOUS; if (l <= strlen("AUTH ANONYMOUS")) r = bus_socket_auth_write(b, "DATA\r\n"); else r = bus_socket_auth_write_ok(b); } } else if (line_begins(line, l, "AUTH EXTERNAL")) { r = verify_external_token(b, line + strlen("AUTH EXTERNAL"), l - strlen("AUTH EXTERNAL")); if (r < 0) return r; if (r == 0) r = bus_socket_auth_write(b, "REJECTED\r\n"); else { b->auth = BUS_AUTH_EXTERNAL; if (l <= strlen("AUTH EXTERNAL")) r = bus_socket_auth_write(b, "DATA\r\n"); else r = bus_socket_auth_write_ok(b); } } else if (line_begins(line, l, "AUTH")) r = bus_socket_auth_write(b, "REJECTED EXTERNAL ANONYMOUS\r\n"); else if (line_equals(line, l, "CANCEL") || line_begins(line, l, "ERROR")) { b->auth = _BUS_AUTH_INVALID; r = bus_socket_auth_write(b, "REJECTED\r\n"); } else if (line_equals(line, l, "BEGIN")) { if (b->auth == _BUS_AUTH_INVALID) r = bus_socket_auth_write(b, "ERROR\r\n"); else { /* We can't leave from the auth phase * before we haven't written * everything queued, so let's check * that */ if (bus_socket_auth_needs_write(b)) return 1; b->rbuffer_size -= (e + 2 - (char*) b->rbuffer); memmove(b->rbuffer, e + 2, b->rbuffer_size); return bus_start_running(b); } } else if (line_begins(line, l, "DATA")) { if (b->auth == _BUS_AUTH_INVALID) r = bus_socket_auth_write(b, "ERROR\r\n"); else { if (b->auth == BUS_AUTH_ANONYMOUS) r = verify_anonymous_token(b, line + 4, l - 4); else r = verify_external_token(b, line + 4, l - 4); if (r < 0) return r; if (r == 0) { b->auth = _BUS_AUTH_INVALID; r = bus_socket_auth_write(b, "REJECTED\r\n"); } else r = bus_socket_auth_write_ok(b); } } else if (line_equals(line, l, "NEGOTIATE_UNIX_FD")) { if (b->auth == _BUS_AUTH_INVALID || !b->accept_fd) r = bus_socket_auth_write(b, "ERROR\r\n"); else { b->can_fds = true; r = bus_socket_auth_write(b, "AGREE_UNIX_FD\r\n"); } } else r = bus_socket_auth_write(b, "ERROR\r\n"); if (r < 0) return r; b->auth_rbegin = e + 2 - (char*) b->rbuffer; processed = true; } } static int bus_socket_auth_verify(sd_bus *b) { assert(b); if (b->is_server) return bus_socket_auth_verify_server(b); else return bus_socket_auth_verify_client(b); } static int bus_socket_read_auth(sd_bus *b) { struct msghdr mh; struct iovec iov = {}; size_t n; ssize_t k; int r; void *p; CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)) control; bool handle_cmsg = false; assert(b); assert(b->state == BUS_AUTHENTICATING); r = bus_socket_auth_verify(b); if (r != 0) return r; n = MAX(256u, b->rbuffer_size * 2); if (n > BUS_AUTH_SIZE_MAX) n = BUS_AUTH_SIZE_MAX; if (b->rbuffer_size >= n) return -ENOBUFS; p = realloc(b->rbuffer, n); if (!p) return -ENOMEM; b->rbuffer = p; iov = IOVEC_MAKE((uint8_t *)b->rbuffer + b->rbuffer_size, n - b->rbuffer_size); if (b->prefer_readv) { k = readv(b->input_fd, &iov, 1); if (k < 0) k = -errno; } else { mh = (struct msghdr) { .msg_iov = &iov, .msg_iovlen = 1, .msg_control = &control, .msg_controllen = sizeof(control), }; k = recvmsg_safe(b->input_fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC); if (k == -ENOTSOCK) { b->prefer_readv = true; k = readv(b->input_fd, &iov, 1); if (k < 0) k = -errno; } else handle_cmsg = true; } if (k < 0) { if (ERRNO_IS_TRANSIENT(k)) return 0; return (int) k; } if (k == 0) { if (handle_cmsg) cmsg_close_all(&mh); /* paranoia, we shouldn't have gotten any fds on EOF */ return -ECONNRESET; } b->rbuffer_size += k; if (handle_cmsg) { struct cmsghdr *cmsg; CMSG_FOREACH(cmsg, &mh) if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) { int j; /* Whut? We received fds during the auth * protocol? Somebody is playing games with * us. Close them all, and fail */ j = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); close_many((int*) CMSG_DATA(cmsg), j); return -EIO; } else log_debug("Got unexpected auxiliary data with level=%d and type=%d", cmsg->cmsg_level, cmsg->cmsg_type); } r = bus_socket_auth_verify(b); if (r != 0) return r; return 1; } void bus_socket_setup(sd_bus *b) { assert(b); /* Increase the buffers to 8 MB */ (void) fd_inc_rcvbuf(b->input_fd, SNDBUF_SIZE); (void) fd_inc_sndbuf(b->output_fd, SNDBUF_SIZE); b->message_version = 1; b->message_endian = 0; } static void bus_get_peercred(sd_bus *b) { int r; assert(b); assert(!b->ucred_valid); assert(!b->label); assert(b->n_groups == SIZE_MAX); /* Get the peer for socketpair() sockets */ b->ucred_valid = getpeercred(b->input_fd, &b->ucred) >= 0; /* 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"); /* 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"); } static int bus_socket_start_auth_client(sd_bus *b) { static const char sasl_auth_anonymous[] = { /* * We use an arbitrary trace-string for the ANONYMOUS authentication. It can be used by the * message broker to aid debugging of clients. We fully anonymize the connection and use a * static default. */ "\0AUTH ANONYMOUS\r\n" /* HEX a n o n y m o u s */ "DATA 616e6f6e796d6f7573\r\n" }; static const char sasl_auth_external[] = { "\0AUTH EXTERNAL\r\n" "DATA\r\n" }; static const char sasl_negotiate_unix_fd[] = { "NEGOTIATE_UNIX_FD\r\n" }; static const char sasl_begin[] = { "BEGIN\r\n" }; size_t i = 0; assert(b); if (b->anonymous_auth) b->auth_iovec[i++] = IOVEC_MAKE((char*) sasl_auth_anonymous, sizeof(sasl_auth_anonymous) - 1); else b->auth_iovec[i++] = IOVEC_MAKE((char*) sasl_auth_external, sizeof(sasl_auth_external) - 1); if (b->accept_fd) b->auth_iovec[i++] = IOVEC_MAKE_STRING(sasl_negotiate_unix_fd); b->auth_iovec[i++] = IOVEC_MAKE_STRING(sasl_begin); return bus_socket_write_auth(b); } int bus_socket_start_auth(sd_bus *b) { assert(b); bus_get_peercred(b); bus_set_state(b, BUS_AUTHENTICATING); b->auth_timeout = now(CLOCK_MONOTONIC) + BUS_AUTH_TIMEOUT; if (sd_is_socket(b->input_fd, AF_UNIX, 0, 0) <= 0) b->accept_fd = false; if (b->output_fd != b->input_fd) if (sd_is_socket(b->output_fd, AF_UNIX, 0, 0) <= 0) b->accept_fd = false; if (b->is_server) return bus_socket_read_auth(b); else return bus_socket_start_auth_client(b); } static int bus_socket_inotify_setup(sd_bus *b) { _cleanup_free_ int *new_watches = NULL; _cleanup_free_ char *absolute = NULL; size_t n = 0, done = 0, i; unsigned max_follow = 32; const char *p; int wd, r; assert(b); assert(b->watch_bind); assert(b->sockaddr.sa.sa_family == AF_UNIX); assert(b->sockaddr.un.sun_path[0] != 0); /* Sets up an inotify fd in case watch_bind is enabled: wait until the configured AF_UNIX file system socket * appears before connecting to it. The implemented is pretty simplistic: we just subscribe to relevant changes * to all prefix components of the path, and every time we get an event for that we try to reconnect again, * without actually caring what precisely the event we got told us. If we still can't connect we re-subscribe * to all relevant changes of anything in the path, so that our watches include any possibly newly created path * components. */ if (b->inotify_fd < 0) { b->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC); if (b->inotify_fd < 0) return -errno; b->inotify_fd = fd_move_above_stdio(b->inotify_fd); } /* Make sure the path is NUL terminated */ p = strndupa_safe(b->sockaddr.un.sun_path, sizeof(b->sockaddr.un.sun_path)); /* Make sure the path is absolute */ r = path_make_absolute_cwd(p, &absolute); if (r < 0) goto fail; /* Watch all parent directories, and don't mind any prefix that doesn't exist yet. For the innermost directory * that exists we want to know when files are created or moved into it. For all parents of it we just care if * they are removed or renamed. */ if (!GREEDY_REALLOC(new_watches, n + 1)) { r = -ENOMEM; goto fail; } /* Start with the top-level directory, which is a bit simpler than the rest, since it can't be a symlink, and * always exists */ wd = inotify_add_watch(b->inotify_fd, "/", IN_CREATE|IN_MOVED_TO); if (wd < 0) { r = log_debug_errno(errno, "Failed to add inotify watch on /: %m"); goto fail; } else new_watches[n++] = wd; for (;;) { _cleanup_free_ char *component = NULL, *prefix = NULL, *destination = NULL; size_t n_slashes, n_component; char *c = NULL; n_slashes = strspn(absolute + done, "/"); n_component = n_slashes + strcspn(absolute + done + n_slashes, "/"); if (n_component == 0) /* The end */ break; component = strndup(absolute + done, n_component); if (!component) { r = -ENOMEM; goto fail; } /* A trailing slash? That's a directory, and not a socket then */ if (path_equal(component, "/")) { r = -EISDIR; goto fail; } /* A single dot? Let's eat this up */ if (path_equal(component, "/.")) { done += n_component; continue; } prefix = strndup(absolute, done + n_component); if (!prefix) { r = -ENOMEM; goto fail; } if (!GREEDY_REALLOC(new_watches, n + 1)) { r = -ENOMEM; goto fail; } wd = inotify_add_watch(b->inotify_fd, prefix, IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CREATE|IN_MOVED_TO|IN_DONT_FOLLOW); log_debug("Added inotify watch for %s on bus %s: %i", prefix, strna(b->description), wd); if (wd < 0) { if (IN_SET(errno, ENOENT, ELOOP)) break; /* This component doesn't exist yet, or the path contains a cyclic symlink right now */ r = log_debug_errno(errno, "Failed to add inotify watch on %s: %m", empty_to_root(prefix)); goto fail; } else new_watches[n++] = wd; /* Check if this is possibly a symlink. If so, let's follow it and watch it too. */ r = readlink_malloc(prefix, &destination); if (r == -EINVAL) { /* not a symlink */ done += n_component; continue; } if (r < 0) goto fail; if (isempty(destination)) { /* Empty symlink target? Yuck! */ r = -EINVAL; goto fail; } if (max_follow <= 0) { /* Let's make sure we don't follow symlinks forever */ r = -ELOOP; goto fail; } if (path_is_absolute(destination)) { /* For absolute symlinks we build the new path and start anew */ c = strjoin(destination, absolute + done + n_component); done = 0; } else { _cleanup_free_ char *t = NULL; /* For relative symlinks we replace the last component, and try again */ t = strndup(absolute, done); if (!t) return -ENOMEM; c = strjoin(t, "/", destination, absolute + done + n_component); } if (!c) { r = -ENOMEM; goto fail; } free(absolute); absolute = c; max_follow--; } /* And now, let's remove all watches from the previous iteration we don't need anymore */ for (i = 0; i < b->n_inotify_watches; i++) { bool found = false; size_t j; for (j = 0; j < n; j++) if (new_watches[j] == b->inotify_watches[i]) { found = true; break; } if (found) continue; (void) inotify_rm_watch(b->inotify_fd, b->inotify_watches[i]); } free_and_replace(b->inotify_watches, new_watches); b->n_inotify_watches = n; return 0; fail: bus_close_inotify_fd(b); return r; } int bus_socket_connect(sd_bus *b) { bool inotify_done = false; int r; assert(b); for (;;) { assert(b->input_fd < 0); assert(b->output_fd < 0); assert(b->sockaddr.sa.sa_family != AF_UNSPEC); if (DEBUG_LOGGING) { _cleanup_free_ char *pretty = NULL; (void) sockaddr_pretty(&b->sockaddr.sa, b->sockaddr_size, false, true, &pretty); log_debug("sd-bus: starting bus%s%s by connecting to %s...", b->description ? " " : "", strempty(b->description), strnull(pretty)); } b->input_fd = socket(b->sockaddr.sa.sa_family, SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, 0); if (b->input_fd < 0) return -errno; b->input_fd = fd_move_above_stdio(b->input_fd); 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) { /* If we have any inotify watches open, close them now, we don't need them anymore, as * we have successfully initiated a connection */ bus_close_inotify_fd(b); /* Note that very likely we are already in BUS_OPENING state here, as we enter it when * we start parsing the address string. The only reason we set the state explicitly * here, is to undo BUS_WATCH_BIND, in case we did the inotify magic. */ bus_set_state(b, BUS_OPENING); return 1; } if (IN_SET(errno, 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) { /* This connection attempt failed, let's release the socket for now, and start with a * fresh one when reconnecting. */ bus_close_io_fds(b); if (inotify_done) { /* inotify set up already, don't do it again, just return now, and remember * that we are waiting for inotify events now. */ bus_set_state(b, BUS_WATCH_BIND); return 1; } /* This is a file system socket, and the inotify logic is enabled. Let's create the necessary inotify fd. */ r = bus_socket_inotify_setup(b); if (r < 0) return r; /* Let's now try to connect a second time, because in theory there's otherwise a race * here: the socket might have been created in the time between our first connect() and * the time we set up the inotify logic. But let's remember that we set up inotify now, * so that we don't do the connect() more than twice. */ inotify_done = true; } else return -errno; } else break; } /* Yay, established, we don't need no inotify anymore! */ bus_close_inotify_fd(b); return bus_socket_start_auth(b); } int bus_socket_exec(sd_bus *b) { int s[2], r; assert(b); assert(b->input_fd < 0); assert(b->output_fd < 0); assert(b->exec_path); assert(b->busexec_pid == 0); if (DEBUG_LOGGING) { _cleanup_free_ char *line = NULL; if (b->exec_argv) line = quote_command_line(b->exec_argv, SHELL_ESCAPE_EMPTY); log_debug("sd-bus: starting bus%s%s with %s%s", b->description ? " " : "", strempty(b->description), line ?: b->exec_path, b->exec_argv && !line ? "…" : ""); } r = socketpair(AF_UNIX, SOCK_STREAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0, s); if (r < 0) return -errno; r = safe_fork_full("(sd-busexec)", s+1, 1, FORK_RESET_SIGNALS|FORK_CLOSE_ALL_FDS, &b->busexec_pid); if (r < 0) { safe_close_pair(s); return r; } if (r == 0) { /* Child */ r = rearrange_stdio(s[1], s[1], STDERR_FILENO); TAKE_FD(s[1]); if (r < 0) _exit(EXIT_FAILURE); (void) rlimit_nofile_safe(); if (b->exec_argv) execvp(b->exec_path, b->exec_argv); else execvp(b->exec_path, STRV_MAKE(b->exec_path)); _exit(EXIT_FAILURE); } safe_close(s[1]); b->output_fd = b->input_fd = fd_move_above_stdio(s[0]); bus_socket_setup(b); return bus_socket_start_auth(b); } int bus_socket_take_fd(sd_bus *b) { assert(b); bus_socket_setup(b); return bus_socket_start_auth(b); } int bus_socket_write_message(sd_bus *bus, sd_bus_message *m, size_t *idx) { struct iovec *iov; ssize_t k; size_t n; unsigned j; int r; assert(bus); assert(m); assert(idx); assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO)); if (*idx >= BUS_MESSAGE_SIZE(m)) return 0; r = bus_message_setup_iovec(m); if (r < 0) return r; n = m->n_iovec * sizeof(struct iovec); iov = newa(struct iovec, n); memcpy_safe(iov, m->iovec, n); j = 0; iovec_advance(iov, &j, *idx); if (bus->prefer_writev) k = writev(bus->output_fd, iov, m->n_iovec); else { struct msghdr mh = { .msg_iov = iov, .msg_iovlen = m->n_iovec, }; if (m->n_fds > 0 && *idx == 0) { struct cmsghdr *control; mh.msg_controllen = CMSG_SPACE(sizeof(int) * m->n_fds); mh.msg_control = alloca0(mh.msg_controllen); control = CMSG_FIRSTHDR(&mh); control->cmsg_len = CMSG_LEN(sizeof(int) * m->n_fds); control->cmsg_level = SOL_SOCKET; control->cmsg_type = SCM_RIGHTS; memcpy(CMSG_DATA(control), m->fds, sizeof(int) * m->n_fds); } k = sendmsg(bus->output_fd, &mh, MSG_DONTWAIT|MSG_NOSIGNAL); if (k < 0 && errno == ENOTSOCK) { bus->prefer_writev = true; k = writev(bus->output_fd, iov, m->n_iovec); } } if (k < 0) return ERRNO_IS_TRANSIENT(errno) ? 0 : -errno; *idx += (size_t) k; return 1; } static int bus_socket_read_message_need(sd_bus *bus, size_t *need) { uint32_t a, b; uint8_t e; uint64_t sum; assert(bus); assert(need); assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO)); if (bus->rbuffer_size < sizeof(struct bus_header)) { *need = sizeof(struct bus_header) + 8; /* Minimum message size: * * Header + * * Method Call: +2 string headers * Signal: +3 string headers * Method Error: +1 string headers * +1 uint32 headers * Method Reply: +1 uint32 headers * * A string header is at least 9 bytes * A uint32 header is at least 8 bytes * * Hence the minimum message size of a valid message * is header + 8 bytes */ return 0; } a = ((const uint32_t*) bus->rbuffer)[1]; b = ((const uint32_t*) bus->rbuffer)[3]; e = ((const uint8_t*) bus->rbuffer)[0]; if (e == BUS_LITTLE_ENDIAN) { a = le32toh(a); b = le32toh(b); } else if (e == BUS_BIG_ENDIAN) { a = be32toh(a); b = be32toh(b); } else return -EBADMSG; sum = (uint64_t) sizeof(struct bus_header) + (uint64_t) ALIGN_TO(b, 8) + (uint64_t) a; if (sum >= BUS_MESSAGE_SIZE_MAX) return -ENOBUFS; *need = (size_t) sum; return 0; } static int bus_socket_make_message(sd_bus *bus, size_t size) { sd_bus_message *t = NULL; void *b; int r; assert(bus); assert(bus->rbuffer_size >= size); assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO)); r = bus_rqueue_make_room(bus); if (r < 0) return r; if (bus->rbuffer_size > size) { b = memdup((const uint8_t*) bus->rbuffer + size, bus->rbuffer_size - size); if (!b) return -ENOMEM; } else b = NULL; r = bus_message_from_malloc(bus, bus->rbuffer, size, bus->fds, bus->n_fds, NULL, &t); if (r == -EBADMSG) { log_debug_errno(r, "Received invalid message from connection %s, dropping.", strna(bus->description)); free(bus->rbuffer); /* We want to drop current rbuffer and proceed with whatever remains in b */ } else if (r < 0) { free(b); return r; } /* rbuffer ownership was either transferred to t, or we got EBADMSG and dropped it. */ bus->rbuffer = b; bus->rbuffer_size -= size; bus->fds = NULL; bus->n_fds = 0; if (t) { t->read_counter = ++bus->read_counter; bus->rqueue[bus->rqueue_size++] = bus_message_ref_queued(t, bus); sd_bus_message_unref(t); } return 1; } int bus_socket_read_message(sd_bus *bus) { struct msghdr mh; struct iovec iov = {}; ssize_t k; size_t need; int r; void *b; CMSG_BUFFER_TYPE(CMSG_SPACE(sizeof(int) * BUS_FDS_MAX)) control; bool handle_cmsg = false; assert(bus); assert(IN_SET(bus->state, BUS_RUNNING, BUS_HELLO)); r = bus_socket_read_message_need(bus, &need); if (r < 0) return r; if (bus->rbuffer_size >= need) return bus_socket_make_message(bus, need); b = realloc(bus->rbuffer, need); if (!b) return -ENOMEM; bus->rbuffer = b; iov = IOVEC_MAKE((uint8_t *)bus->rbuffer + bus->rbuffer_size, need - bus->rbuffer_size); if (bus->prefer_readv) { k = readv(bus->input_fd, &iov, 1); if (k < 0) k = -errno; } else { mh = (struct msghdr) { .msg_iov = &iov, .msg_iovlen = 1, .msg_control = &control, .msg_controllen = sizeof(control), }; k = recvmsg_safe(bus->input_fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC); if (k == -ENOTSOCK) { bus->prefer_readv = true; k = readv(bus->input_fd, &iov, 1); if (k < 0) k = -errno; } else handle_cmsg = true; } if (k < 0) { if (ERRNO_IS_TRANSIENT(k)) return 0; return (int) k; } if (k == 0) { if (handle_cmsg) cmsg_close_all(&mh); /* On EOF we shouldn't have gotten an fd, but let's make sure */ return -ECONNRESET; } bus->rbuffer_size += k; if (handle_cmsg) { struct cmsghdr *cmsg; CMSG_FOREACH(cmsg, &mh) if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) { int n, *f, i; n = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int); if (!bus->can_fds) { /* Whut? We received fds but this * isn't actually enabled? Close them, * and fail */ close_many((int*) CMSG_DATA(cmsg), n); return -EIO; } f = reallocarray(bus->fds, bus->n_fds + n, sizeof(int)); if (!f) { close_many((int*) CMSG_DATA(cmsg), n); return -ENOMEM; } for (i = 0; i < n; i++) f[bus->n_fds++] = fd_move_above_stdio(((int*) CMSG_DATA(cmsg))[i]); bus->fds = f; } else log_debug("Got unexpected auxiliary data with level=%d and type=%d", cmsg->cmsg_level, cmsg->cmsg_type); } r = bus_socket_read_message_need(bus, &need); if (r < 0) return r; if (bus->rbuffer_size >= need) return bus_socket_make_message(bus, need); return 1; } int bus_socket_process_opening(sd_bus *b) { int error = 0, events, r; socklen_t slen = sizeof(error); assert(b->state == BUS_OPENING); events = fd_wait_for_event(b->output_fd, POLLOUT, 0); if (events < 0) return events; if (!(events & (POLLOUT|POLLERR|POLLHUP))) return 0; r = getsockopt(b->output_fd, SOL_SOCKET, SO_ERROR, &error, &slen); if (r < 0) b->last_connect_error = errno; else if (error != 0) b->last_connect_error = error; else if (events & (POLLERR|POLLHUP)) b->last_connect_error = ECONNREFUSED; else return bus_socket_start_auth(b); return bus_next_address(b); } int bus_socket_process_authenticating(sd_bus *b) { int r; assert(b); assert(b->state == BUS_AUTHENTICATING); if (now(CLOCK_MONOTONIC) >= b->auth_timeout) return -ETIMEDOUT; r = bus_socket_write_auth(b); if (r != 0) return r; return bus_socket_read_auth(b); } int bus_socket_process_watch_bind(sd_bus *b) { int r, q; assert(b); assert(b->state == BUS_WATCH_BIND); assert(b->inotify_fd >= 0); r = flush_fd(b->inotify_fd); if (r <= 0) return r; log_debug("Got inotify event on bus %s.", strna(b->description)); /* We flushed events out of the inotify fd. In that case, maybe the socket is valid now? Let's try to connect * to it again */ r = bus_socket_connect(b); if (r < 0) return r; q = bus_attach_io_events(b); if (q < 0) return q; q = bus_attach_inotify_event(b); if (q < 0) return q; return r; }