diff options
Diffstat (limited to 'src/libbus-proxy-core/proxy.c')
| -rw-r--r-- | src/libbus-proxy-core/proxy.c | 953 |
1 files changed, 953 insertions, 0 deletions
diff --git a/src/libbus-proxy-core/proxy.c b/src/libbus-proxy-core/proxy.c new file mode 100644 index 0000000000..bcfbab0dad --- /dev/null +++ b/src/libbus-proxy-core/proxy.c @@ -0,0 +1,953 @@ +/*** + This file is part of systemd. + + Copyright 2010 Lennart Poettering + Copyright 2013 Daniel Mack + Copyright 2014 Kay Sievers + Copyright 2014 David Herrmann + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <errno.h> +#include <poll.h> +#include <string.h> +#include <sys/socket.h> +#include <sys/types.h> + +#include <systemd/sd-bus.h> +#include <systemd/sd-daemon.h> + +#include "alloc-util.h" +#include "bus-control.h" +#include "bus-internal.h" +#include "bus-message.h" +#include "bus-util.h" +#include "bus-xml-policy.h" +#include "driver.h" +#include "fd-util.h" +#include "formats-util.h" +#include "log.h" +#include "proxy.h" +#include "set.h" +#include "strv.h" +#include "synthesize.h" +#include "user-util.h" +#include "util.h" + +static int proxy_create_destination(Proxy *p, const char *destination, const char *local_sec, bool negotiate_fds) { + _cleanup_(sd_bus_flush_close_unrefp) sd_bus *b = NULL; + int r; + + r = sd_bus_new(&b); + if (r < 0) + return log_error_errno(r, "Failed to allocate bus: %m"); + + r = sd_bus_set_description(b, "sd-proxy"); + if (r < 0) + return log_error_errno(r, "Failed to set bus name: %m"); + + r = sd_bus_set_address(b, destination); + if (r < 0) + return log_error_errno(r, "Failed to set address to connect to: %m"); + + r = sd_bus_negotiate_fds(b, negotiate_fds); + if (r < 0) + return log_error_errno(r, "Failed to set FD negotiation: %m"); + + r = sd_bus_negotiate_creds(b, true, SD_BUS_CREDS_EUID|SD_BUS_CREDS_PID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SELINUX_CONTEXT); + if (r < 0) + return log_error_errno(r, "Failed to set credential negotiation: %m"); + + if (p->local_creds.pid > 0) { + b->fake_pids.pid = p->local_creds.pid; + b->fake_pids_valid = true; + + b->fake_creds.uid = UID_INVALID; + b->fake_creds.euid = p->local_creds.uid; + b->fake_creds.suid = UID_INVALID; + b->fake_creds.fsuid = UID_INVALID; + b->fake_creds.gid = GID_INVALID; + b->fake_creds.egid = p->local_creds.gid; + b->fake_creds.sgid = GID_INVALID; + b->fake_creds.fsgid = GID_INVALID; + b->fake_creds_valid = true; + } + + if (local_sec) { + b->fake_label = strdup(local_sec); + if (!b->fake_label) + return log_oom(); + } + + b->manual_peer_interface = true; + + r = sd_bus_start(b); + if (r < 0) + return log_error_errno(r, "Failed to start bus client: %m"); + + p->destination_bus = b; + b = NULL; + return 0; +} + +static int proxy_create_local(Proxy *p, bool negotiate_fds) { + sd_id128_t server_id; + sd_bus *b; + int r; + + r = sd_bus_new(&b); + if (r < 0) + return log_error_errno(r, "Failed to allocate bus: %m"); + + r = sd_bus_set_fd(b, p->local_in, p->local_out); + if (r < 0) { + sd_bus_unref(b); + return log_error_errno(r, "Failed to set fds: %m"); + } + + /* The fds are now owned by the bus, and we indicate that by + * storing the bus object in the proxy object. */ + p->local_bus = b; + + r = sd_bus_get_bus_id(p->destination_bus, &server_id); + if (r < 0) + return log_error_errno(r, "Failed to get server ID: %m"); + + r = sd_bus_set_server(b, 1, server_id); + if (r < 0) + return log_error_errno(r, "Failed to set server mode: %m"); + + r = sd_bus_negotiate_fds(b, negotiate_fds); + if (r < 0) + return log_error_errno(r, "Failed to set FD negotiation: %m"); + + r = sd_bus_negotiate_creds(b, true, SD_BUS_CREDS_EUID|SD_BUS_CREDS_PID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_SELINUX_CONTEXT); + if (r < 0) + return log_error_errno(r, "Failed to set credential negotiation: %m"); + + r = sd_bus_set_anonymous(b, true); + if (r < 0) + return log_error_errno(r, "Failed to set anonymous authentication: %m"); + + b->manual_peer_interface = true; + + r = sd_bus_start(b); + if (r < 0) + return log_error_errno(r, "Failed to start bus client: %m"); + + return 0; +} + +static int proxy_match_synthetic(sd_bus_message *m, void *userdata, sd_bus_error *error) { + Proxy *p = userdata; + + p->synthetic_matched = true; + return 0; /* make sure to continue processing it in further handlers */ +} + +/* + * We always need NameOwnerChanged so we can synthesize NameLost and + * NameAcquired. Furthermore, dbus-1 always passes unicast-signals through, so + * subscribe unconditionally. + */ +static int proxy_prepare_matches(Proxy *p) { + _cleanup_free_ char *match = NULL; + const char *unique; + int r; + + if (!p->destination_bus->is_kernel) + return 0; + + r = sd_bus_get_unique_name(p->destination_bus, &unique); + if (r < 0) + return log_error_errno(r, "Failed to get unique name: %m"); + + match = strjoin("type='signal'," + "sender='org.freedesktop.DBus'," + "path='/org/freedesktop/DBus'," + "interface='org.freedesktop.DBus'," + "member='NameOwnerChanged'," + "arg1='", + unique, + "'", + NULL); + if (!match) + return log_oom(); + + r = sd_bus_add_match(p->destination_bus, NULL, match, proxy_match_synthetic, p); + if (r < 0) + return log_error_errno(r, "Failed to add match for NameLost: %m"); + + free(match); + match = strjoin("type='signal'," + "sender='org.freedesktop.DBus'," + "path='/org/freedesktop/DBus'," + "interface='org.freedesktop.DBus'," + "member='NameOwnerChanged'," + "arg2='", + unique, + "'", + NULL); + if (!match) + return log_oom(); + + r = sd_bus_add_match(p->destination_bus, NULL, match, proxy_match_synthetic, p); + if (r < 0) + return log_error_errno(r, "Failed to add match for NameAcquired: %m"); + + free(match); + match = strjoin("type='signal'," + "destination='", + unique, + "'", + NULL); + if (!match) + return log_oom(); + + r = sd_bus_add_match(p->destination_bus, NULL, match, proxy_match_synthetic, p); + if (r < 0) + log_error_errno(r, "Failed to add match for directed signals: %m"); + /* FIXME: temporarily ignore error to support older kdbus versions */ + + return 0; +} + +int proxy_new(Proxy **out, int in_fd, int out_fd, const char *destination) { + _cleanup_(proxy_freep) Proxy *p = NULL; + _cleanup_free_ char *local_sec = NULL; + bool is_unix; + int r; + + /* This takes possession/destroys the file descriptors passed + * in even on failure. The caller should hence forget about + * the fds in all cases after calling this function and not + * close them. */ + + p = new0(Proxy, 1); + if (!p) { + safe_close(in_fd); + safe_close(out_fd); + return log_oom(); + } + + p->local_in = in_fd; + p->local_out = out_fd; + + p->owned_names = set_new(&string_hash_ops); + if (!p->owned_names) + return log_oom(); + + is_unix = sd_is_socket(in_fd, AF_UNIX, 0, 0) > 0 && + sd_is_socket(out_fd, AF_UNIX, 0, 0) > 0; + + if (is_unix) { + (void) getpeercred(in_fd, &p->local_creds); + (void) getpeersec(in_fd, &local_sec); + } + + r = proxy_create_destination(p, destination, local_sec, is_unix); + if (r < 0) + return r; + + r = proxy_create_local(p, is_unix); + if (r < 0) + return r; + + r = proxy_prepare_matches(p); + if (r < 0) + return r; + + *out = p; + p = NULL; + + return 0; +} + +Proxy *proxy_free(Proxy *p) { + ProxyActivation *activation; + + if (!p) + return NULL; + + while ((activation = p->activations)) { + LIST_REMOVE(activations_by_proxy, p->activations, activation); + sd_bus_message_unref(activation->request); + sd_bus_slot_unref(activation->slot); + free(activation); + } + + if (p->local_bus) + sd_bus_flush_close_unref(p->local_bus); + else { + safe_close(p->local_in); + if (p->local_out != p->local_in) + safe_close(p->local_out); + } + + sd_bus_flush_close_unref(p->destination_bus); + set_free_free(p->owned_names); + free(p); + + return NULL; +} + +int proxy_set_policy(Proxy *p, SharedPolicy *sp, char **configuration) { + _cleanup_strv_free_ char **strv = NULL; + Policy *policy; + int r; + + assert(p); + assert(sp); + + /* no need to load legacy policy if destination is not kdbus */ + if (!p->destination_bus->is_kernel) + return 0; + + p->policy = sp; + + policy = shared_policy_acquire(sp); + if (policy) { + /* policy already pre-loaded */ + shared_policy_release(sp, policy); + return 0; + } + + if (!configuration) { + const char *scope; + + r = sd_bus_get_scope(p->destination_bus, &scope); + if (r < 0) + return log_error_errno(r, "Couldn't determine bus scope: %m"); + + if (streq(scope, "system")) + strv = strv_new("/usr/share/dbus-1/system.conf", + "/etc/dbus-1/system.conf", + "/usr/share/dbus-1/system.d/", + "/etc/dbus-1/system.d/", + "/etc/dbus-1/system-local.conf", + NULL); + else if (streq(scope, "user")) + strv = strv_new("/usr/share/dbus-1/session.conf", + "/etc/dbus-1/session.conf", + "/usr/share/dbus-1/session.d/", + "/etc/dbus-1/session.d/", + "/etc/dbus-1/session-local.conf", + NULL); + else + return log_error("Unknown scope %s, don't know which policy to load. Refusing.", scope); + + if (!strv) + return log_oom(); + + configuration = strv; + } + + return shared_policy_preload(sp, configuration); +} + +int proxy_hello_policy(Proxy *p, uid_t original_uid) { + Policy *policy; + int r = 0; + + assert(p); + + if (!p->policy) + return 0; + + policy = shared_policy_acquire(p->policy); + + if (p->local_creds.uid == original_uid) + log_debug("Permitting access, since bus owner matches bus client."); + else if (policy_check_hello(policy, p->local_creds.uid, p->local_creds.gid)) + log_debug("Permitting access due to XML policy."); + else + r = log_error_errno(EPERM, "Policy denied connection."); + + shared_policy_release(p->policy, policy); + + return r; +} + +static int proxy_wait(Proxy *p) { + uint64_t timeout_destination, timeout_local, t; + int events_destination, events_local, fd; + struct timespec _ts, *ts; + struct pollfd *pollfd; + int r; + + assert(p); + + fd = sd_bus_get_fd(p->destination_bus); + if (fd < 0) + return log_error_errno(fd, "Failed to get fd: %m"); + + events_destination = sd_bus_get_events(p->destination_bus); + if (events_destination < 0) + return log_error_errno(events_destination, "Failed to get events mask: %m"); + + r = sd_bus_get_timeout(p->destination_bus, &timeout_destination); + if (r < 0) + return log_error_errno(r, "Failed to get timeout: %m"); + + events_local = sd_bus_get_events(p->local_bus); + if (events_local < 0) + return log_error_errno(events_local, "Failed to get events mask: %m"); + + r = sd_bus_get_timeout(p->local_bus, &timeout_local); + if (r < 0) + return log_error_errno(r, "Failed to get timeout: %m"); + + t = timeout_destination; + if (t == (uint64_t) -1 || (timeout_local != (uint64_t) -1 && timeout_local < timeout_destination)) + t = timeout_local; + + if (t == (uint64_t) -1) + ts = NULL; + else { + usec_t nw; + + nw = now(CLOCK_MONOTONIC); + if (t > nw) + t -= nw; + else + t = 0; + + ts = timespec_store(&_ts, t); + } + + pollfd = (struct pollfd[3]) { + { .fd = fd, .events = events_destination, }, + { .fd = p->local_in, .events = events_local & POLLIN, }, + { .fd = p->local_out, .events = events_local & POLLOUT, }, + }; + + r = ppoll(pollfd, 3, ts, NULL); + if (r < 0) + return log_error_errno(errno, "ppoll() failed: %m"); + + return 0; +} + +static int handle_policy_error(sd_bus_message *m, int r) { + if (r == -ESRCH || r == -ENXIO) + return synthetic_reply_method_errorf(m, SD_BUS_ERROR_NAME_HAS_NO_OWNER, "Name %s is currently not owned by anyone.", m->destination); + + return r; +} + +static int process_policy_unlocked(sd_bus *from, sd_bus *to, sd_bus_message *m, Policy *policy, const struct ucred *our_ucred, Set *owned_names) { + int r; + + assert(from); + assert(to); + assert(m); + + if (!policy) + return 0; + + /* + * dbus-1 distinguishes expected and non-expected replies by tracking + * method-calls and timeouts. By default, DENY rules are *NEVER* applied + * on expected replies, unless explicitly specified. But we dont track + * method-calls, thus, we cannot know whether a reply is expected. + * Fortunately, the kdbus forbids non-expected replies, so we can safely + * ignore any policy on those and let the kernel deal with it. + * + * TODO: To be correct, we should only ignore policy-tags that are + * applied on non-expected replies. However, so far we don't parse those + * tags so we let everything pass. I haven't seen a DENY policy tag on + * expected-replies, ever, so don't bother.. + */ + if (m->reply_cookie > 0) + return 0; + + if (from->is_kernel) { + uid_t sender_uid = UID_INVALID; + gid_t sender_gid = GID_INVALID; + char **sender_names = NULL; + + /* Driver messages are always OK */ + if (streq_ptr(m->sender, "org.freedesktop.DBus")) + return 0; + + /* The message came from the kernel, and is sent to our legacy client. */ + (void) sd_bus_creds_get_well_known_names(&m->creds, &sender_names); + + (void) sd_bus_creds_get_euid(&m->creds, &sender_uid); + (void) sd_bus_creds_get_egid(&m->creds, &sender_gid); + + if (sender_uid == UID_INVALID || sender_gid == GID_INVALID) { + _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *sender_creds = NULL; + + /* If the message came from another legacy + * client, then the message creds will be + * missing, simply because on legacy clients + * per-message creds were unknown. In this + * case, query the creds of the peer + * instead. */ + + r = bus_get_name_creds_kdbus(from, m->sender, SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID, true, &sender_creds); + if (r < 0) + return handle_policy_error(m, r); + + (void) sd_bus_creds_get_euid(sender_creds, &sender_uid); + (void) sd_bus_creds_get_egid(sender_creds, &sender_gid); + } + + /* First check whether the sender can send the message to our name */ + if (policy_check_send(policy, sender_uid, sender_gid, m->header->type, owned_names, NULL, m->path, m->interface, m->member, false, NULL) && + policy_check_recv(policy, our_ucred->uid, our_ucred->gid, m->header->type, NULL, sender_names, m->path, m->interface, m->member, false)) + return 0; + + /* Return an error back to the caller */ + if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL) + return synthetic_reply_method_errorf(m, SD_BUS_ERROR_ACCESS_DENIED, "Access prohibited by XML receiver policy."); + + /* Return 1, indicating that the message shall not be processed any further */ + return 1; + } + + if (to->is_kernel) { + _cleanup_(sd_bus_creds_unrefp) sd_bus_creds *destination_creds = NULL; + uid_t destination_uid = UID_INVALID; + gid_t destination_gid = GID_INVALID; + const char *destination_unique = NULL; + char **destination_names = NULL; + char *n; + + /* Driver messages are always OK */ + if (streq_ptr(m->destination, "org.freedesktop.DBus")) + return 0; + + /* The message came from the legacy client, and is sent to kdbus. */ + if (m->destination) { + r = bus_get_name_creds_kdbus(to, m->destination, + SD_BUS_CREDS_WELL_KNOWN_NAMES|SD_BUS_CREDS_UNIQUE_NAME| + SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|SD_BUS_CREDS_PID, + true, &destination_creds); + if (r < 0) + return handle_policy_error(m, r); + + r = sd_bus_creds_get_unique_name(destination_creds, &destination_unique); + if (r < 0) + return handle_policy_error(m, r); + + (void) sd_bus_creds_get_well_known_names(destination_creds, &destination_names); + + (void) sd_bus_creds_get_euid(destination_creds, &destination_uid); + (void) sd_bus_creds_get_egid(destination_creds, &destination_gid); + } + + /* First check if we (the sender) can send to this name */ + if (sd_bus_message_is_signal(m, NULL, NULL)) { + /* If we forward a signal from dbus-1 to kdbus, we have + * no idea who the recipient is. Therefore, we cannot + * apply any dbus-1 policies that match on receiver + * credentials. We know sd-bus always sets + * KDBUS_MSG_SIGNAL, so the kernel applies policies to + * the message. Therefore, skip policy checks in this + * case. */ + return 0; + } else if (policy_check_send(policy, our_ucred->uid, our_ucred->gid, m->header->type, NULL, destination_names, m->path, m->interface, m->member, true, &n)) { + if (n) { + /* If we made a receiver decision, then remember which + * name's policy we used, and to which unique ID it + * mapped when we made the decision. Then, let's pass + * this to the kernel when sending the message, so that + * it refuses the operation should the name and unique + * ID not map to each other anymore. */ + + r = free_and_strdup(&m->destination_ptr, n); + if (r < 0) + return r; + + r = bus_kernel_parse_unique_name(destination_unique, &m->verify_destination_id); + if (r < 0) + return r; + } + + if (policy_check_recv(policy, destination_uid, destination_gid, m->header->type, owned_names, NULL, m->path, m->interface, m->member, true)) + return 0; + } + + /* Return an error back to the caller */ + if (m->header->type == SD_BUS_MESSAGE_METHOD_CALL) + return synthetic_reply_method_errorf(m, SD_BUS_ERROR_ACCESS_DENIED, "Access prohibited by XML sender policy."); + + /* Return 1, indicating that the message shall not be processed any further */ + return 1; + } + + return 0; +} + +static int process_policy(sd_bus *from, sd_bus *to, sd_bus_message *m, SharedPolicy *sp, const struct ucred *our_ucred, Set *owned_names) { + Policy *policy; + int r; + + assert(sp); + + policy = shared_policy_acquire(sp); + r = process_policy_unlocked(from, to, m, policy, our_ucred, owned_names); + shared_policy_release(sp, policy); + + return r; +} + +static int process_hello(Proxy *p, sd_bus_message *m) { + _cleanup_(sd_bus_message_unrefp) sd_bus_message *n = NULL; + bool is_hello; + int r; + + assert(p); + assert(m); + + /* As reaction to hello we need to respond with two messages: + * the callback reply and the NameAcquired for the unique + * name, since hello is otherwise obsolete on kdbus. */ + + is_hello = + sd_bus_message_is_method_call(m, "org.freedesktop.DBus", "Hello") && + streq_ptr(m->destination, "org.freedesktop.DBus"); + + if (!is_hello) { + if (p->got_hello) + return 0; + + return log_error_errno(EIO, "First packet isn't hello (it's %s.%s), aborting.", m->interface, m->member); + } + + if (p->got_hello) + return log_error_errno(EIO, "Got duplicate hello, aborting."); + + p->got_hello = true; + + if (!p->destination_bus->is_kernel) + return 0; + + r = sd_bus_message_new_method_return(m, &n); + if (r < 0) + return log_error_errno(r, "Failed to generate HELLO reply: %m"); + + r = sd_bus_message_append(n, "s", p->destination_bus->unique_name); + if (r < 0) + return log_error_errno(r, "Failed to append unique name to HELLO reply: %m"); + + r = bus_message_append_sender(n, "org.freedesktop.DBus"); + if (r < 0) + return log_error_errno(r, "Failed to append sender to HELLO reply: %m"); + + r = bus_seal_synthetic_message(p->local_bus, n); + if (r < 0) + return log_error_errno(r, "Failed to seal HELLO reply: %m"); + + r = sd_bus_send(p->local_bus, n, NULL); + if (r < 0) + return log_error_errno(r, "Failed to send HELLO reply: %m"); + + n = sd_bus_message_unref(n); + r = sd_bus_message_new_signal( + p->local_bus, + &n, + "/org/freedesktop/DBus", + "org.freedesktop.DBus", + "NameAcquired"); + if (r < 0) + return log_error_errno(r, "Failed to allocate initial NameAcquired message: %m"); + + r = sd_bus_message_append(n, "s", p->destination_bus->unique_name); + if (r < 0) + return log_error_errno(r, "Failed to append unique name to NameAcquired message: %m"); + + r = bus_message_append_sender(n, "org.freedesktop.DBus"); + if (r < 0) + return log_error_errno(r, "Failed to append sender to NameAcquired message: %m"); + + r = sd_bus_message_set_destination(n, p->destination_bus->unique_name); + if (r < 0) + return log_error_errno(r, "Failed to set destination for NameAcquired message: %m"); + + r = bus_seal_synthetic_message(p->local_bus, n); + if (r < 0) + return log_error_errno(r, "Failed to seal NameAcquired message: %m"); + + r = sd_bus_send(p->local_bus, n, NULL); + if (r < 0) + return log_error_errno(r, "Failed to send NameAcquired message: %m"); + + return 1; +} + +static int patch_sender(sd_bus *a, sd_bus_message *m) { + char **well_known = NULL; + sd_bus_creds *c; + int r; + + assert(a); + assert(m); + + if (!a->is_kernel) + return 0; + + /* We will change the sender of messages from the bus driver + * so that they originate from the bus driver. This is a + * speciality originating from dbus1, where the bus driver did + * not have a unique id, but only the well-known name. */ + + c = sd_bus_message_get_creds(m); + if (!c) + return 0; + + r = sd_bus_creds_get_well_known_names(c, &well_known); + if (r < 0) + return r; + + if (strv_contains(well_known, "org.freedesktop.DBus")) + m->sender = "org.freedesktop.DBus"; + + return 0; +} + +static int proxy_process_destination_to_local(Proxy *p) { + _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL; + bool matched, matched_synthetic; + int r; + + assert(p); + + /* + * Usually, we would just take any message that the bus passes to us + * and forward it to the local connection. However, there are actually + * applications that fail if they receive broadcasts that they didn't + * subscribe to. Therefore, we actually emulate a real broadcast + * matching here, and discard any broadcasts that weren't matched. Our + * match-handlers remembers whether a message was matched by any rule, + * by marking it in @p->message_matched. + */ + + r = sd_bus_process(p->destination_bus, &m); + + matched = p->message_matched; + matched_synthetic = p->synthetic_matched; + p->message_matched = false; + p->synthetic_matched = false; + + if (r == -ECONNRESET || r == -ENOTCONN) /* Treat 'connection reset by peer' as clean exit condition */ + return r; + if (r < 0) { + log_error_errno(r, "Failed to process destination bus: %m"); + return r; + } + if (r == 0) + return 0; + if (!m) + return 1; + + /* We officially got EOF, let's quit */ + if (sd_bus_message_is_signal(m, "org.freedesktop.DBus.Local", "Disconnected")) + return -ECONNRESET; + + r = synthesize_name_acquired(p, p->destination_bus, p->local_bus, m); + if (r == -ECONNRESET || r == -ENOTCONN) + return r; + if (r < 0) + return log_error_errno(r, "Failed to synthesize message: %m"); + + /* discard broadcasts that were not matched by any MATCH rule */ + if (!matched && !sd_bus_message_get_destination(m)) { + if (!matched_synthetic) + log_debug("Dropped unmatched broadcast: uid=" UID_FMT " gid=" GID_FMT " pid=" PID_FMT " message=%s path=%s interface=%s member=%s sender=%s destination=%s", + p->local_creds.uid, p->local_creds.gid, p->local_creds.pid, bus_message_type_to_string(m->header->type), + strna(m->path), strna(m->interface), strna(m->member), strna(m->sender), strna(m->destination)); + return 1; + } + + patch_sender(p->destination_bus, m); + + if (p->policy) { + r = process_policy(p->destination_bus, p->local_bus, m, p->policy, &p->local_creds, p->owned_names); + if (r == -ECONNRESET || r == -ENOTCONN) + return r; + if (r < 0) + return log_error_errno(r, "Failed to process policy: %m"); + if (r > 0) + return 1; + } + + r = sd_bus_send(p->local_bus, m, NULL); + if (r < 0) { + if (r == -ECONNRESET || r == -ENOTCONN) + return r; + + /* If the peer tries to send a reply and it is + * rejected with EBADSLT by the kernel, we ignore the + * error. This catches cases where the original + * method-call didn't had EXPECT_REPLY set, but the + * proxy-peer still sends a reply. This is allowed in + * dbus1, but not in kdbus. We don't want to track + * reply-windows in the proxy, so we simply ignore + * EBADSLT for all replies. The only downside is, that + * callers are no longer notified if their replies are + * dropped. However, this is equivalent to the + * caller's timeout to expire, so this should be + * acceptable. Nobody sane sends replies without a + * matching method-call, so nobody should care. */ + + /* FIXME: remove -EPERM when kdbus is updated */ + if ((r == -EPERM || r == -EBADSLT) && m->reply_cookie > 0) + return 1; + + /* Return the error to the client, if we can */ + synthetic_reply_method_errnof(m, r, "Failed to forward message we got from destination: %m"); + if (r == -ENOBUFS) { + /* if local dbus1 peer does not dispatch its queue, warn only once */ + if (!p->queue_overflow) + log_error("Dropped messages due to queue overflow of local peer (pid: "PID_FMT" uid: "UID_FMT")", p->local_creds.pid, p->local_creds.uid); + p->queue_overflow = true; + } else + log_error_errno(r, + "Failed to forward message we got from destination: uid=" UID_FMT " gid=" GID_FMT" message=%s destination=%s path=%s interface=%s member=%s: %m", + p->local_creds.uid, p->local_creds.gid, bus_message_type_to_string(m->header->type), + strna(m->destination), strna(m->path), strna(m->interface), strna(m->member)); + + return 1; + } + + p->queue_overflow = false; + return 1; +} + +static int proxy_process_local_to_destination(Proxy *p) { + _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL; + int r; + + assert(p); + + r = sd_bus_process(p->local_bus, &m); + if (r == -ECONNRESET || r == -ENOTCONN) /* Treat 'connection reset by peer' as clean exit condition */ + return r; + if (r < 0) { + log_error_errno(r, "Failed to process local bus: %m"); + return r; + } + if (r == 0) + return 0; + if (!m) + return 1; + + /* We officially got EOF, let's quit */ + if (sd_bus_message_is_signal(m, "org.freedesktop.DBus.Local", "Disconnected")) + return -ECONNRESET; + + r = process_hello(p, m); + if (r == -ECONNRESET || r == -ENOTCONN) + return r; + if (r < 0) + return log_error_errno(r, "Failed to process HELLO: %m"); + if (r > 0) + return 1; + + r = bus_proxy_process_driver(p, p->destination_bus, p->local_bus, m, p->policy, &p->local_creds, p->owned_names); + if (r == -ECONNRESET || r == -ENOTCONN) + return r; + if (r < 0) + return log_error_errno(r, "Failed to process driver calls: %m"); + if (r > 0) + return 1; + + for (;;) { + if (p->policy) { + r = process_policy(p->local_bus, p->destination_bus, m, p->policy, &p->local_creds, p->owned_names); + if (r == -ECONNRESET || r == -ENOTCONN) + return r; + if (r < 0) + return log_error_errno(r, "Failed to process policy: %m"); + if (r > 0) + return 1; + } + + r = sd_bus_send(p->destination_bus, m, NULL); + if (r < 0) { + if (r == -ECONNRESET || r == -ENOTCONN) + return r; + + /* The name database changed since the policy check, hence let's check again */ + if (r == -EREMCHG) + continue; + + /* see above why EBADSLT is ignored for replies */ + if ((r == -EPERM || r == -EBADSLT) && m->reply_cookie > 0) + return 1; + + synthetic_reply_method_errnof(m, r, "Failed to forward message we got from local: %m"); + log_error_errno(r, + "Failed to forward message we got from local: uid=" UID_FMT " gid=" GID_FMT" message=%s destination=%s path=%s interface=%s member=%s: %m", + p->local_creds.uid, p->local_creds.gid, bus_message_type_to_string(m->header->type), + strna(m->destination), strna(m->path), strna(m->interface), strna(m->member)); + return 1; + } + + break; + } + + return 1; +} + +int proxy_match(sd_bus_message *m, void *userdata, sd_bus_error *error) { + Proxy *p = userdata; + + p->message_matched = true; + return 0; /* make sure to continue processing it in further handlers */ +} + +int proxy_run(Proxy *p) { + int r; + + assert(p); + + for (;;) { + bool busy = false; + + if (p->got_hello) { + /* Read messages from bus, to pass them on to our client */ + r = proxy_process_destination_to_local(p); + if (r == -ECONNRESET || r == -ENOTCONN) + return 0; + if (r < 0) + return r; + if (r > 0) + busy = true; + } + + /* Read messages from our client, to pass them on to the bus */ + r = proxy_process_local_to_destination(p); + if (r == -ECONNRESET || r == -ENOTCONN) + return 0; + if (r < 0) + return r; + if (r > 0) + busy = true; + + if (!busy) { + r = proxy_wait(p); + if (r == -ECONNRESET || r == -ENOTCONN) + return 0; + if (r < 0) + return r; + } + } + + return 0; +} |