src/bus-proxyd/bus-xml-policy.h \
src/bus-proxyd/driver.c \
src/bus-proxyd/driver.h \
+ src/bus-proxyd/proxy.c \
+ src/bus-proxyd/proxy.h \
src/bus-proxyd/synthesize.c \
src/bus-proxyd/synthesize.h
#include "set.h"
#include "bus-xml-policy.h"
#include "driver.h"
+#include "proxy.h"
#include "synthesize.h"
static char *arg_address = NULL;
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(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;
- bool granted = false;
-
- /* 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. */
- sd_bus_creds_get_well_known_names(&m->creds, &sender_names);
-
- (void) sd_bus_creds_get_uid(&m->creds, &sender_uid);
- (void) sd_bus_creds_get_gid(&m->creds, &sender_gid);
-
- if (sender_uid == UID_INVALID || sender_gid == GID_INVALID) {
- _cleanup_bus_creds_unref_ 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_UID|SD_BUS_CREDS_GID, true, &sender_creds);
- if (r < 0)
- return handle_policy_error(m, r);
-
- (void) sd_bus_creds_get_uid(sender_creds, &sender_uid);
- (void) sd_bus_creds_get_gid(sender_creds, &sender_gid);
- }
-
- /* First check whether the sender can send the message to our name */
- if (set_isempty(owned_names)) {
- if (policy_check_send(policy, sender_uid, sender_gid, m->header->type, NULL, m->path, m->interface, m->member, false))
- granted = true;
- } else {
- Iterator i;
- char *n;
-
- SET_FOREACH(n, owned_names, i)
- if (policy_check_send(policy, sender_uid, sender_gid, m->header->type, n, m->path, m->interface, m->member, false)) {
- granted = true;
- break;
- }
- }
-
- if (granted) {
- /* Then check whether us (the recipient) can receive from the sender's name */
- if (strv_isempty(sender_names)) {
- if (policy_check_recv(policy, our_ucred->uid, our_ucred->gid, m->header->type, NULL, m->path, m->interface, m->member, false))
- return 0;
- } else {
- char **n;
-
- STRV_FOREACH(n, sender_names) {
- if (policy_check_recv(policy, our_ucred->uid, our_ucred->gid, m->header->type, *n, 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_bus_creds_unref_ 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;
- bool granted = false;
-
- /* 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_UID|SD_BUS_CREDS_GID|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);
-
- sd_bus_creds_get_well_known_names(destination_creds, &destination_names);
-
- (void) sd_bus_creds_get_uid(destination_creds, &destination_uid);
- (void) sd_bus_creds_get_gid(destination_creds, &destination_gid);
- }
-
- /* First check if we (the sender) can send to this name */
- if (strv_isempty(destination_names)) {
- if (policy_check_send(policy, our_ucred->uid, our_ucred->gid, m->header->type, NULL, m->path, m->interface, m->member, true))
- granted = true;
- } else {
- char **n;
-
- STRV_FOREACH(n, destination_names) {
- if (policy_check_send(policy, our_ucred->uid, our_ucred->gid, m->header->type, *n, m->path, m->interface, m->member, true)) {
-
- /* 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)
- break;
-
- granted = true;
- break;
- }
- }
- }
-
- /* Then check if the recipient can receive from our name */
- if (granted) {
- 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
- * receiver policies that match on receiver
- * credentials. We know sd-bus always sets
- * KDBUS_MSG_SIGNAL, so the kernel applies
- * receiver policies to the message. Therefore,
- * skip policy checks in this case. */
- return 0;
- } else if (set_isempty(owned_names)) {
- if (policy_check_recv(policy, destination_uid, destination_gid, m->header->type, NULL, m->path, m->interface, m->member, true))
- return 0;
- } else {
- Iterator i;
- char *n;
-
- SET_FOREACH(n, owned_names, i)
- if (policy_check_recv(policy, destination_uid, destination_gid, m->header->type, n, 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_hello(sd_bus *a, sd_bus *b, sd_bus_message *m, bool *got_hello) {
- _cleanup_bus_message_unref_ sd_bus_message *n = NULL;
- bool is_hello;
- int r;
-
- assert(a);
- assert(b);
- assert(m);
- assert(got_hello);
-
- /* 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 (*got_hello)
- return 0;
-
- log_error("First packet isn't hello (it's %s.%s), aborting.", m->interface, m->member);
- return -EIO;
- }
-
- if (*got_hello) {
- log_error("Got duplicate hello, aborting.");
- return -EIO;
- }
-
- *got_hello = true;
-
- if (!a->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", a->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(b, n);
- if (r < 0)
- return log_error_errno(r, "Failed to seal HELLO reply: %m");
-
- r = sd_bus_send(b, 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(
- b,
- &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", a->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 = bus_seal_synthetic_message(b, n);
- if (r < 0)
- return log_error_errno(r, "Failed to seal NameAcquired message: %m");
-
- r = sd_bus_send(b, 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 bus_new_destination(sd_bus **out, struct ucred *ucred, const char *peersec, bool negotiate_fds) {
- _cleanup_bus_close_unref_ sd_bus *a = NULL;
- int r;
-
- r = sd_bus_new(&a);
- if (r < 0)
- return log_error_errno(r, "Failed to allocate bus: %m");
-
- r = sd_bus_set_description(a, "sd-proxy");
- if (r < 0)
- return log_error_errno(r, "Failed to set bus name: %m");
-
- r = sd_bus_set_address(a, arg_address);
- if (r < 0)
- return log_error_errno(r, "Failed to set address to connect to: %m");
-
- r = sd_bus_negotiate_fds(a, negotiate_fds);
- if (r < 0)
- return log_error_errno(r, "Failed to set FD negotiation: %m");
-
- r = sd_bus_negotiate_creds(a, true, SD_BUS_CREDS_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_GID|SD_BUS_CREDS_SELINUX_CONTEXT);
- if (r < 0)
- return log_error_errno(r, "Failed to set credential negotiation: %m");
-
- if (ucred->pid > 0) {
- a->fake_pids.pid = ucred->pid;
- a->fake_pids_valid = true;
-
- a->fake_creds.uid = ucred->uid;
- a->fake_creds.euid = UID_INVALID;
- a->fake_creds.suid = UID_INVALID;
- a->fake_creds.fsuid = UID_INVALID;
- a->fake_creds.gid = ucred->gid;
- a->fake_creds.egid = GID_INVALID;
- a->fake_creds.sgid = GID_INVALID;
- a->fake_creds.fsgid = GID_INVALID;
- a->fake_creds_valid = true;
- }
-
- if (peersec) {
- a->fake_label = strdup(peersec);
- if (!a->fake_label)
- return log_oom();
- }
-
- a->manual_peer_interface = true;
-
- r = sd_bus_start(a);
- if (r < 0)
- return log_error_errno(r, "Failed to start bus client: %m");
-
- *out = a;
- a = NULL;
- return 0;
-}
-
-static int bus_new_local(sd_bus **out, sd_bus *dest, int in_fd, int out_fd, bool negotiate_fds) {
- _cleanup_bus_close_unref_ sd_bus *b = NULL;
- sd_id128_t server_id;
- 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, in_fd, out_fd);
- if (r < 0)
- return log_error_errno(r, "Failed to set fds: %m");
-
- r = sd_bus_get_bus_id(dest, &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_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_GID|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");
-
- *out = b;
- b = NULL;
- return 0;
-}
-
-static int mac_smack_apply_label_and_drop_cap_mac_admin(pid_t its_pid, const char *new_label) {
-#ifdef HAVE_SMACK
- int r = 0, k;
-
- if (!mac_smack_use())
- return 0;
-
- if (new_label && its_pid > 0)
- r = mac_smack_apply_pid(its_pid, new_label);
-
- k = drop_capability(CAP_MAC_ADMIN);
- return r < 0 ? r : k;
-#else
- return 0;
-#endif
-}
-
-
int main(int argc, char *argv[]) {
-
- _cleanup_bus_close_unref_ sd_bus *a = NULL, *b = NULL;
+ _cleanup_(proxy_freep) Proxy *p = NULL;
int r, in_fd, out_fd;
- bool got_hello = false;
- bool is_unix;
- struct ucred ucred = {};
- _cleanup_free_ char *peersec = NULL;
- Policy policy_buffer = {}, *policy = NULL;
- _cleanup_set_free_free_ Set *owned_names = NULL;
uid_t original_uid;
log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
original_uid = getuid();
- 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, &ucred);
- (void) getpeersec(in_fd, &peersec);
-
- r = mac_smack_apply_label_and_drop_cap_mac_admin(getpid(), peersec);
- if (r < 0)
- log_warning_errno(r, "Failed to set SMACK label (%s) and drop CAP_MAC_ADMIN: %m", peersec);
- }
-
if (arg_drop_privileges) {
const char *user = "systemd-bus-proxy";
uid_t uid;
goto finish;
}
- owned_names = set_new(&string_hash_ops);
- if (!owned_names) {
- log_oom();
+ r = proxy_new(&p, in_fd, out_fd, arg_address);
+ if (r < 0)
goto finish;
- }
- r = bus_new_destination(&a, &ucred, peersec, is_unix);
+ r = proxy_load_policy(p, arg_configuration);
if (r < 0)
goto finish;
- if (a->is_kernel) {
- if (!arg_configuration) {
- const char *scope;
-
- r = sd_bus_get_scope(a, &scope);
- if (r < 0) {
- log_error_errno(r, "Couldn't determine bus scope: %m");
- goto finish;
- }
-
- if (streq(scope, "system"))
- arg_configuration = strv_new(
- "/etc/dbus-1/system.conf",
- "/etc/dbus-1/system.d/",
- "/etc/dbus-1/system-local.conf",
- NULL);
- else if (streq(scope, "user"))
- arg_configuration = strv_new(
- "/etc/dbus-1/session.conf",
- "/etc/dbus-1/session.d/",
- "/etc/dbus-1/session-local.conf",
- NULL);
- else {
- log_error("Unknown scope %s, don't know which policy to load. Refusing.", scope);
- goto finish;
- }
-
- if (!arg_configuration) {
- r = log_oom();
- goto finish;
- }
- }
-
- r = policy_load(&policy_buffer, arg_configuration);
- if (r < 0) {
- log_error_errno(r, "Failed to load policy: %m");
- goto finish;
- }
-
- policy = &policy_buffer;
- /* policy_dump(policy); */
-
- if (ucred.uid == original_uid)
- log_debug("Permitting access, since bus owner matches bus client.");
- else if (policy_check_hello(policy, ucred.uid, ucred.gid))
- log_debug("Permitting access due to XML policy.");
- else {
- r = log_error_errno(EPERM, "Policy denied connection.");
- goto finish;
- }
- }
-
- r = bus_new_local(&b, a, in_fd, out_fd, is_unix);
+ r = proxy_hello_policy(p, original_uid);
if (r < 0)
goto finish;
- r = rename_service(a, b);
+ r = rename_service(p->dest_bus, p->local_bus);
if (r < 0)
log_debug_errno(r, "Failed to rename process: %m");
- if (a->is_kernel) {
- _cleanup_free_ char *match = NULL;
- const char *unique;
-
- r = sd_bus_get_unique_name(a, &unique);
- if (r < 0) {
- log_error_errno(r, "Failed to get unique name: %m");
- goto finish;
- }
-
- match = strjoin("type='signal',"
- "sender='org.freedesktop.DBus',"
- "path='/org/freedesktop/DBus',"
- "interface='org.freedesktop.DBus',"
- "member='NameOwnerChanged',"
- "arg1='",
- unique,
- "'",
- NULL);
- if (!match) {
- log_oom();
- goto finish;
- }
-
- r = sd_bus_add_match(a, NULL, match, NULL, NULL);
- if (r < 0) {
- log_error_errno(r, "Failed to add match for NameLost: %m");
- goto finish;
- }
-
- 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) {
- log_oom();
- goto finish;
- }
-
- r = sd_bus_add_match(a, NULL, match, NULL, NULL);
- if (r < 0) {
- log_error_errno(r, "Failed to add match for NameAcquired: %m");
- goto finish;
- }
- }
-
- for (;;) {
- _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
- int events_a, events_b, fd;
- uint64_t timeout_a, timeout_b, t;
- struct timespec _ts, *ts;
- struct pollfd *pollfd;
- int k;
-
- if (got_hello) {
- /* Read messages from bus, to pass them on to our client */
-
- r = sd_bus_process(a, &m);
- if (r < 0) {
- /* treat 'connection reset by peer' as clean exit condition */
- if (r == -ECONNRESET)
- r = 0;
- else
- log_error_errno(r, "Failed to process bus a: %m");
-
- goto finish;
- }
-
- if (m) {
- bool processed = false;
-
- /* We officially got EOF, let's quit */
- if (sd_bus_message_is_signal(m, "org.freedesktop.DBus.Local", "Disconnected")) {
- r = 0;
- goto finish;
- }
-
- k = synthesize_name_acquired(a, b, m);
- if (k < 0) {
- r = k;
- log_error_errno(r, "Failed to synthesize message: %m");
- goto finish;
- }
-
- patch_sender(a, m);
-
- if (policy) {
- k = process_policy(a, b, m, policy, &ucred, owned_names);
- if (k < 0) {
- r = k;
- log_error_errno(r, "Failed to process policy: %m");
- goto finish;
- } else if (k > 0) {
- r = 1;
- processed = true;
- }
- }
-
- if (!processed) {
- k = sd_bus_send(b, m, NULL);
- if (k < 0) {
- if (k == -ECONNRESET) {
- r = 0;
- goto finish;
- } else if (k == -EPERM && m->reply_cookie > 0) {
- /* If the peer tries to send a reply and it is rejected with EPERM
- * 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
- * EPERM 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. */
- r = 1;
- } else {
- r = k;
- log_error_errno(r, "Failed to send message to client: %m");
- goto finish;
- }
- } else
- r = 1;
- }
- }
-
- if (r > 0)
- continue;
- }
-
- /* Read messages from our client, to pass them on to the bus */
- r = sd_bus_process(b, &m);
- if (r < 0) {
- /* treat 'connection reset by peer' as clean exit condition */
- if (r == -ECONNRESET)
- r = 0;
- else
- log_error_errno(r, "Failed to process bus b: %m");
-
- goto finish;
- }
-
- if (m) {
- bool processed = false;
-
- /* We officially got EOF, let's quit */
- if (sd_bus_message_is_signal(m, "org.freedesktop.DBus.Local", "Disconnected")) {
- r = 0;
- goto finish;
- }
-
- k = process_hello(a, b, m, &got_hello);
- if (k < 0) {
- r = k;
- log_error_errno(r, "Failed to process HELLO: %m");
- goto finish;
- } else if (k > 0) {
- processed = true;
- r = 1;
- }
-
- if (!processed) {
- k = bus_proxy_process_driver(a, b, m, policy, &ucred, owned_names);
- if (k < 0) {
- r = k;
- log_error_errno(r, "Failed to process driver calls: %m");
- goto finish;
- } else if (k > 0) {
- processed = true;
- r = 1;
- }
-
- if (!processed) {
-
- for (;;) {
- if (policy) {
- k = process_policy(b, a, m, policy, &ucred, owned_names);
- if (k < 0) {
- r = k;
- log_error_errno(r, "Failed to process policy: %m");
- goto finish;
- } else if (k > 0) {
- processed = true;
- r = 1;
- break;
- }
- }
-
- k = sd_bus_send(a, m, NULL);
- if (k < 0) {
- if (k == -EREMCHG) {
- /* The name database changed since the policy check, hence let's check again */
- continue;
- } else if (k == -ECONNRESET) {
- r = 0;
- goto finish;
- } else if (k == -EPERM && m->reply_cookie > 0) {
- /* see above why EPERM is ignored for replies */
- r = 1;
- } else {
- r = k;
- log_error_errno(r, "Failed to send message to bus: %m");
- goto finish;
- }
- } else
- r = 1;
-
- break;
- }
- }
- }
- }
-
- if (r > 0)
- continue;
-
- fd = sd_bus_get_fd(a);
- if (fd < 0) {
- log_error_errno(r, "Failed to get fd: %m");
- goto finish;
- }
-
- events_a = sd_bus_get_events(a);
- if (events_a < 0) {
- log_error_errno(r, "Failed to get events mask: %m");
- goto finish;
- }
-
- r = sd_bus_get_timeout(a, &timeout_a);
- if (r < 0) {
- log_error_errno(r, "Failed to get timeout: %m");
- goto finish;
- }
-
- events_b = sd_bus_get_events(b);
- if (events_b < 0) {
- log_error_errno(r, "Failed to get events mask: %m");
- goto finish;
- }
-
- r = sd_bus_get_timeout(b, &timeout_b);
- if (r < 0) {
- log_error_errno(r, "Failed to get timeout: %m");
- goto finish;
- }
-
- t = timeout_a;
- if (t == (uint64_t) -1 || (timeout_b != (uint64_t) -1 && timeout_b < timeout_a))
- t = timeout_b;
-
- 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_a, },
- {.fd = in_fd, .events = events_b & POLLIN, },
- {.fd = out_fd, .events = events_b & POLLOUT, }
- };
-
- r = ppoll(pollfd, 3, ts, NULL);
- if (r < 0) {
- log_error_errno(errno, "ppoll() failed: %m");
- goto finish;
- }
- }
+ r = proxy_run(p);
finish:
sd_notify(false,
"STOPPING=1\n"
"STATUS=Shutting down.");
- policy_free(&policy_buffer);
strv_free(arg_configuration);
free(arg_address);
--- /dev/null
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ 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 <sys/socket.h>
+#include <sys/un.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/poll.h>
+#include <stddef.h>
+#include <getopt.h>
+
+#include "log.h"
+#include "util.h"
+#include "socket-util.h"
+#include "sd-daemon.h"
+#include "sd-bus.h"
+#include "bus-internal.h"
+#include "bus-message.h"
+#include "bus-util.h"
+#include "build.h"
+#include "strv.h"
+#include "def.h"
+#include "capability.h"
+#include "bus-control.h"
+#include "smack-util.h"
+#include "set.h"
+#include "bus-xml-policy.h"
+#include "driver.h"
+#include "proxy.h"
+#include "synthesize.h"
+
+static int proxy_create_dest(Proxy *p, const char *dest, const char *local_sec, bool negotiate_fds) {
+ _cleanup_bus_close_unref_ 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, dest);
+ 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_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_GID|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 = p->local_creds.uid;
+ b->fake_creds.euid = UID_INVALID;
+ b->fake_creds.suid = UID_INVALID;
+ b->fake_creds.fsuid = UID_INVALID;
+ b->fake_creds.gid = p->local_creds.gid;
+ b->fake_creds.egid = GID_INVALID;
+ 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->dest_bus = b;
+ b = NULL;
+ return 0;
+}
+
+static int proxy_create_local(Proxy *p, int in_fd, int out_fd, bool negotiate_fds) {
+ _cleanup_bus_close_unref_ sd_bus *b = NULL;
+ sd_id128_t server_id;
+ 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, in_fd, out_fd);
+ if (r < 0)
+ return log_error_errno(r, "Failed to set fds: %m");
+
+ r = sd_bus_get_bus_id(p->dest_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_UID|SD_BUS_CREDS_PID|SD_BUS_CREDS_GID|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");
+
+ p->local_bus = b;
+ b = NULL;
+ return 0;
+}
+
+static int proxy_prepare_matches(Proxy *p) {
+ _cleanup_free_ char *match = NULL;
+ const char *unique;
+ int r;
+
+ if (!p->dest_bus->is_kernel)
+ return 0;
+
+ r = sd_bus_get_unique_name(p->dest_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->dest_bus, NULL, match, NULL, NULL);
+ 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->dest_bus, NULL, match, NULL, NULL);
+ if (r < 0)
+ return log_error_errno(r, "Failed to add match for NameAcquired: %m");
+
+ return 0;
+}
+
+int proxy_new(Proxy **out, int in_fd, int out_fd, const char *dest) {
+ _cleanup_(proxy_freep) Proxy *p = NULL;
+ _cleanup_free_ char *local_sec = NULL;
+ bool is_unix;
+ int r;
+
+ p = new0(Proxy, 1);
+ if (!p)
+ 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_dest(p, dest, local_sec, is_unix);
+ if (r < 0)
+ return r;
+
+ r = proxy_create_local(p, in_fd, out_fd, 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) {
+ if (!p)
+ return NULL;
+
+ sd_bus_close_unrefp(&p->local_bus);
+ sd_bus_close_unrefp(&p->dest_bus);
+ set_free_free(p->owned_names);
+ free(p);
+
+ return NULL;
+}
+
+int proxy_load_policy(Proxy *p, char **configuration) {
+ _cleanup_strv_free_ char **strv = NULL;
+ int r;
+
+ assert(p);
+
+ /* no need to load legacy policy if destination is not kdbus */
+ if (!p->dest_bus->is_kernel)
+ return 0;
+
+ if (!configuration) {
+ const char *scope;
+
+ r = sd_bus_get_scope(p->dest_bus, &scope);
+ if (r < 0)
+ return log_error_errno(r, "Couldn't determine bus scope: %m");
+
+ if (streq(scope, "system"))
+ strv = strv_new("/etc/dbus-1/system.conf",
+ "/etc/dbus-1/system.d/",
+ "/etc/dbus-1/system-local.conf",
+ NULL);
+ else if (streq(scope, "user"))
+ strv = strv_new("/etc/dbus-1/session.conf",
+ "/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;
+ }
+
+ r = policy_load(&p->policy_buffer, configuration);
+ if (r < 0)
+ return log_error_errno(r, "Failed to load policy: %m");
+
+ p->policy = &p->policy_buffer;
+ /* policy_dump(p->policy); */
+
+ return 0;
+}
+
+int proxy_hello_policy(Proxy *p, uid_t original_uid) {
+ assert(p);
+
+ if (!p->policy)
+ return 0;
+
+ if (p->local_creds.uid == original_uid)
+ log_debug("Permitting access, since bus owner matches bus client.");
+ else if (policy_check_hello(p->policy, p->local_creds.uid, p->local_creds.gid))
+ log_debug("Permitting access due to XML policy.");
+ else
+ return log_error_errno(EPERM, "Policy denied connection.");
+
+ return 0;
+}
+
+static int proxy_wait(Proxy *p) {
+ uint64_t timeout_dest, timeout_local, t;
+ int events_dest, events_local, fd;
+ struct timespec _ts, *ts;
+ struct pollfd *pollfd;
+ int r;
+
+ assert(p);
+
+ fd = sd_bus_get_fd(p->dest_bus);
+ if (fd < 0)
+ return log_error_errno(fd, "Failed to get fd: %m");
+
+ events_dest = sd_bus_get_events(p->dest_bus);
+ if (events_dest < 0)
+ return log_error_errno(events_dest, "Failed to get events mask: %m");
+
+ r = sd_bus_get_timeout(p->dest_bus, &timeout_dest);
+ 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_dest;
+ if (t == (uint64_t) -1 || (timeout_local != (uint64_t) -1 && timeout_local < timeout_dest))
+ 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_dest, },
+ { .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(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;
+ bool granted = false;
+
+ /* 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. */
+ sd_bus_creds_get_well_known_names(&m->creds, &sender_names);
+
+ (void) sd_bus_creds_get_uid(&m->creds, &sender_uid);
+ (void) sd_bus_creds_get_gid(&m->creds, &sender_gid);
+
+ if (sender_uid == UID_INVALID || sender_gid == GID_INVALID) {
+ _cleanup_bus_creds_unref_ 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_UID|SD_BUS_CREDS_GID, true, &sender_creds);
+ if (r < 0)
+ return handle_policy_error(m, r);
+
+ (void) sd_bus_creds_get_uid(sender_creds, &sender_uid);
+ (void) sd_bus_creds_get_gid(sender_creds, &sender_gid);
+ }
+
+ /* First check whether the sender can send the message to our name */
+ if (set_isempty(owned_names)) {
+ if (policy_check_send(policy, sender_uid, sender_gid, m->header->type, NULL, m->path, m->interface, m->member, false))
+ granted = true;
+ } else {
+ Iterator i;
+ char *n;
+
+ SET_FOREACH(n, owned_names, i)
+ if (policy_check_send(policy, sender_uid, sender_gid, m->header->type, n, m->path, m->interface, m->member, false)) {
+ granted = true;
+ break;
+ }
+ }
+
+ if (granted) {
+ /* Then check whether us (the recipient) can receive from the sender's name */
+ if (strv_isempty(sender_names)) {
+ if (policy_check_recv(policy, our_ucred->uid, our_ucred->gid, m->header->type, NULL, m->path, m->interface, m->member, false))
+ return 0;
+ } else {
+ char **n;
+
+ STRV_FOREACH(n, sender_names) {
+ if (policy_check_recv(policy, our_ucred->uid, our_ucred->gid, m->header->type, *n, 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_bus_creds_unref_ 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;
+ bool granted = false;
+
+ /* 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_UID|SD_BUS_CREDS_GID|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);
+
+ sd_bus_creds_get_well_known_names(destination_creds, &destination_names);
+
+ (void) sd_bus_creds_get_uid(destination_creds, &destination_uid);
+ (void) sd_bus_creds_get_gid(destination_creds, &destination_gid);
+ }
+
+ /* First check if we (the sender) can send to this name */
+ if (strv_isempty(destination_names)) {
+ if (policy_check_send(policy, our_ucred->uid, our_ucred->gid, m->header->type, NULL, m->path, m->interface, m->member, true))
+ granted = true;
+ } else {
+ char **n;
+
+ STRV_FOREACH(n, destination_names) {
+ if (policy_check_send(policy, our_ucred->uid, our_ucred->gid, m->header->type, *n, m->path, m->interface, m->member, true)) {
+
+ /* 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)
+ break;
+
+ granted = true;
+ break;
+ }
+ }
+ }
+
+ /* Then check if the recipient can receive from our name */
+ if (granted) {
+ 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
+ * receiver policies that match on receiver
+ * credentials. We know sd-bus always sets
+ * KDBUS_MSG_SIGNAL, so the kernel applies
+ * receiver policies to the message. Therefore,
+ * skip policy checks in this case. */
+ return 0;
+ } else if (set_isempty(owned_names)) {
+ if (policy_check_recv(policy, destination_uid, destination_gid, m->header->type, NULL, m->path, m->interface, m->member, true))
+ return 0;
+ } else {
+ Iterator i;
+ char *n;
+
+ SET_FOREACH(n, owned_names, i)
+ if (policy_check_recv(policy, destination_uid, destination_gid, m->header->type, n, 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_hello(Proxy *p, sd_bus_message *m) {
+ _cleanup_bus_message_unref_ 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->dest_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->dest_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->dest_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 = 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_dest_to_local(Proxy *p) {
+ _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+ int r;
+
+ assert(p);
+
+ r = sd_bus_process(p->dest_bus, &m);
+ if (r < 0) {
+ /* treat 'connection reset by peer' as clean exit condition */
+ if (r != -ECONNRESET)
+ 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->dest_bus, p->local_bus, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to synthesize message: %m");
+
+ patch_sender(p->dest_bus, m);
+
+ if (p->policy) {
+ r = process_policy(p->dest_bus, p->local_bus, m, p->policy, &p->local_creds, p->owned_names);
+ if (r < 0)
+ return log_error_errno(r, "Failed to process policy: %m");
+ else if (r > 0)
+ return 1;
+ }
+
+ r = sd_bus_send(p->local_bus, m, NULL);
+ if (r < 0) {
+ if (r == -EPERM && m->reply_cookie > 0) {
+ /* If the peer tries to send a reply and it is rejected with EPERM
+ * 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
+ * EPERM 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. */
+ return 1;
+ } else {
+ if (r != -ECONNRESET)
+ log_error_errno(r, "Failed to send message to client: %m");
+ return r;
+ }
+ }
+
+ return 1;
+}
+
+static int proxy_process_local_to_dest(Proxy *p) {
+ _cleanup_bus_message_unref_ sd_bus_message *m = NULL;
+ int r;
+
+ assert(p);
+
+ r = sd_bus_process(p->local_bus, &m);
+ if (r < 0) {
+ /* treat 'connection reset by peer' as clean exit condition */
+ if (r != -ECONNRESET)
+ 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 < 0)
+ return log_error_errno(r, "Failed to process HELLO: %m");
+ else if (r > 0)
+ return 1;
+
+ r = bus_proxy_process_driver(p->dest_bus, p->local_bus, m, p->policy, &p->local_creds, p->owned_names);
+ if (r < 0)
+ return log_error_errno(r, "Failed to process driver calls: %m");
+ else if (r > 0)
+ return 1;
+
+ for (;;) {
+ if (p->policy) {
+ r = process_policy(p->local_bus, p->dest_bus, m, p->policy, &p->local_creds, p->owned_names);
+ if (r < 0)
+ return log_error_errno(r, "Failed to process policy: %m");
+ else if (r > 0)
+ return 1;
+ }
+
+ r = sd_bus_send(p->dest_bus, m, NULL);
+ if (r < 0) {
+ if (r == -EREMCHG) {
+ /* The name database changed since the policy check, hence let's check again */
+ continue;
+ } else if (r == -EPERM && m->reply_cookie > 0) {
+ /* see above why EPERM is ignored for replies */
+ return 1;
+ } else {
+ if (r != -ECONNRESET)
+ log_error_errno(r, "Failed to send message to bus: %m");
+ return r;
+ }
+ }
+
+ break;
+ }
+
+ return 1;
+}
+
+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_dest_to_local(p);
+ if (r == -ECONNRESET)
+ return 0;
+ else if (r < 0)
+ return r;
+ else if (r > 0)
+ busy = true;
+ }
+
+ /* Read messages from our client, to pass them on to the bus */
+ r = proxy_process_local_to_dest(p);
+ if (r == -ECONNRESET)
+ return 0;
+ else if (r < 0)
+ return r;
+ else if (r > 0)
+ busy = true;
+
+ if (!busy) {
+ r = proxy_wait(p);
+ if (r < 0)
+ return r;
+ }
+ }
+
+ return 0;
+}
--- /dev/null
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+ This file is part of systemd.
+
+ 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 <stdlib.h>
+#include "sd-bus.h"
+#include "bus-xml-policy.h"
+#include "util.h"
+
+typedef struct Proxy Proxy;
+
+struct Proxy {
+ sd_bus *local_bus;
+ struct ucred local_creds;
+ int local_in;
+ int local_out;
+
+ sd_bus *dest_bus;
+
+ Set *owned_names;
+ Policy policy_buffer;
+ Policy *policy;
+
+ bool got_hello : 1;
+};
+
+int proxy_new(Proxy **out, int in_fd, int out_fd, const char *dest);
+Proxy *proxy_free(Proxy *p);
+
+int proxy_load_policy(Proxy *p, char **configuration);
+int proxy_hello_policy(Proxy *p, uid_t original_uid);
+int proxy_run(Proxy *p);
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(Proxy*, proxy_free);
~ianmdlvl / elogind.git / commitdiff