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-rw-r--r--src/libsystemd/sd-bus/bus-socket.c1292
1 files changed, 1292 insertions, 0 deletions
diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
new file mode 100644
index 0000000..441b4a8
--- /dev/null
+++ b/src/libsystemd/sd-bus/bus-socket.c
@@ -0,0 +1,1292 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <endian.h>
+#include <poll.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#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 "fd-util.h"
+#include "format-util.h"
+#include "fs-util.h"
+#include "hexdecoct.h"
+#include "io-util.h"
+#include "macro.h"
+#include "missing.h"
+#include "path-util.h"
+#include "process-util.h"
+#include "rlimit-util.h"
+#include "selinux-util.h"
+#include "signal-util.h"
+#include "stdio-util.h"
+#include "string-util.h"
+#include "user-util.h"
+#include "utf8.h"
+#include "util.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;
+ zero(mh);
+
+ mh.msg_iov = b->auth_iovec + b->auth_index;
+ mh.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 == EAGAIN ? 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 *e, *f, *start;
+ sd_id128_t peer;
+ unsigned i;
+ int r;
+
+ assert(b);
+
+ /* We expect two response lines: "OK" and possibly
+ * "AGREE_UNIX_FD" */
+
+ e = memmem_safe(b->rbuffer, b->rbuffer_size, "\r\n", 2);
+ if (!e)
+ return 0;
+
+ if (b->accept_fd) {
+ f = memmem(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 OK
+ * line */
+
+ if (e - (char*) b->rbuffer != 3 + 32)
+ return -EPERM;
+
+ if (memcmp(b->rbuffer, "OK ", 3))
+ return -EPERM;
+
+ b->auth = b->anonymous_auth ? BUS_AUTH_ANONYMOUS : BUS_AUTH_EXTERNAL;
+
+ for (i = 0; i < 32; i += 2) {
+ int x, y;
+
+ x = unhexchar(((char*) b->rbuffer)[3 + i]);
+ y = unhexchar(((char*) b->rbuffer)[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 second 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, we if
+ * the owner of this bus wanted authentication he 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(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 + 14, l - 14);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ r = bus_socket_auth_write(b, "REJECTED\r\n");
+ else {
+ b->auth = BUS_AUTH_ANONYMOUS;
+ r = bus_socket_auth_write_ok(b);
+ }
+
+ } else if (line_begins(line, l, "AUTH EXTERNAL")) {
+
+ r = verify_external_token(b, line + 13, l - 13);
+ if (r < 0)
+ return r;
+ if (r == 0)
+ r = bus_socket_auth_write(b, "REJECTED\r\n");
+ else {
+ b->auth = BUS_AUTH_EXTERNAL;
+ 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;
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[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);
+ else {
+ zero(mh);
+ mh.msg_iov = &iov;
+ mh.msg_iovlen = 1;
+ mh.msg_control = &control;
+ mh.msg_controllen = sizeof(control);
+
+ k = recvmsg(b->input_fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
+ if (k < 0 && errno == ENOTSOCK) {
+ b->prefer_readv = true;
+ k = readv(b->input_fd, &iov, 1);
+ } else
+ handle_cmsg = true;
+ }
+ if (k < 0)
+ return errno == EAGAIN ? 0 : -errno;
+ if (k == 0)
+ 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_t) -1);
+
+ /* 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) {
+ size_t l;
+ const char *auth_suffix, *auth_prefix;
+
+ assert(b);
+
+ if (b->anonymous_auth) {
+ auth_prefix = "\0AUTH ANONYMOUS ";
+
+ /* For ANONYMOUS auth we send some arbitrary "trace" string */
+ l = 9;
+ b->auth_buffer = hexmem("anonymous", l);
+ } else {
+ char text[DECIMAL_STR_MAX(uid_t) + 1];
+
+ auth_prefix = "\0AUTH EXTERNAL ";
+
+ xsprintf(text, UID_FMT, geteuid());
+
+ l = strlen(text);
+ b->auth_buffer = hexmem(text, l);
+ }
+
+ if (!b->auth_buffer)
+ return -ENOMEM;
+
+ if (b->accept_fd)
+ auth_suffix = "\r\nNEGOTIATE_UNIX_FD\r\nBEGIN\r\n";
+ else
+ auth_suffix = "\r\nBEGIN\r\n";
+
+ b->auth_iovec[0] = IOVEC_MAKE((void*) auth_prefix, 1 + strlen(auth_prefix + 1));
+ b->auth_iovec[1] = IOVEC_MAKE(b->auth_buffer, l * 2);
+ b->auth_iovec[2] = IOVEC_MAKE_STRING(auth_suffix);
+
+ 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_allocated = 0, 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(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_allocated, 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_allocated, 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);
+
+ 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);
+
+ 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 */
+
+ if (rearrange_stdio(s[1], s[1], STDERR_FILENO) < 0)
+ _exit(EXIT_FAILURE);
+
+ (void) rlimit_nofile_safe();
+
+ if (b->exec_argv)
+ execvp(b->exec_path, b->exec_argv);
+ else {
+ const char *argv[] = { b->exec_path, NULL };
+ execvp(b->exec_path, (char**) argv);
+ }
+
+ _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_control = control = alloca(CMSG_SPACE(sizeof(int) * m->n_fds));
+ mh.msg_controllen = 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 == EAGAIN ? 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));
+ else if (r < 0) {
+ free(b);
+ return r;
+ }
+
+ bus->rbuffer = b;
+ bus->rbuffer_size -= size;
+
+ bus->fds = NULL;
+ bus->n_fds = 0;
+
+ if (t)
+ bus->rqueue[bus->rqueue_size++] = 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;
+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[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);
+ else {
+ zero(mh);
+ mh.msg_iov = &iov;
+ mh.msg_iovlen = 1;
+ mh.msg_control = &control;
+ mh.msg_controllen = sizeof(control);
+
+ k = recvmsg(bus->input_fd, &mh, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
+ if (k < 0 && errno == ENOTSOCK) {
+ bus->prefer_readv = true;
+ k = readv(bus->input_fd, &iov, 1);
+ } else
+ handle_cmsg = true;
+ }
+ if (k < 0)
+ return errno == EAGAIN ? 0 : -errno;
+ if (k == 0)
+ 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;
+ socklen_t slen = sizeof(error);
+ struct pollfd p = {
+ .fd = b->output_fd,
+ .events = POLLOUT,
+ };
+ int r;
+
+ assert(b->state == BUS_OPENING);
+
+ r = poll(&p, 1, 0);
+ if (r < 0)
+ return -errno;
+
+ if (!(p.revents & (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 (p.revents & (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;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-23 02:48:14 +0000