static int server(sd_bus *bus) {
int r;
bool client1_gone = false, client2_gone = false;
while (!client1_gone || !client2_gone) {
_cleanup_bus_message_unref_ sd_bus_message *m = NULL;
pid_t pid = 0;
const char *label = NULL;
r = sd_bus_process(bus, &m);
if (r < 0) {
log_error_errno(r, "Failed to process requests: %m");
goto fail;
}
if (r == 0) {
r = sd_bus_wait(bus, (uint64_t) -1);
if (r < 0) {
log_error_errno(r, "Failed to wait: %m");
goto fail;
}
continue;
}
if (!m)
continue;
sd_bus_creds_get_pid(sd_bus_message_get_creds(m), &pid);
sd_bus_creds_get_selinux_context(sd_bus_message_get_creds(m), &label);
log_info("Got message! member=%s pid="PID_FMT" label=%s",
strna(sd_bus_message_get_member(m)),
pid,
strna(label));
/* bus_message_dump(m); */
/* sd_bus_message_rewind(m, true); */
if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "LowerCase")) {
const char *hello;
_cleanup_free_ char *lowercase = NULL;
r = sd_bus_message_read(m, "s", &hello);
if (r < 0) {
log_error_errno(r, "Failed to get parameter: %m");
goto fail;
}
lowercase = strdup(hello);
if (!lowercase) {
r = log_oom();
goto fail;
}
ascii_strlower(lowercase);
r = sd_bus_reply_method_return(m, "s", lowercase);
if (r < 0) {
log_error_errno(r, "Failed to send reply: %m");
goto fail;
}
} else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "ExitClient1")) {
r = sd_bus_reply_method_return(m, NULL);
if (r < 0) {
log_error_errno(r, "Failed to send reply: %m");
goto fail;
}
client1_gone = true;
} else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "ExitClient2")) {
r = sd_bus_reply_method_return(m, NULL);
if (r < 0) {
log_error_errno(r, "Failed to send reply: %m");
goto fail;
}
client2_gone = true;
} else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "Slow")) {
sleep(1);
r = sd_bus_reply_method_return(m, NULL);
if (r < 0) {
log_error_errno(r, "Failed to send reply: %m");
goto fail;
}
} else if (sd_bus_message_is_method_call(m, "org.freedesktop.systemd.test", "FileDescriptor")) {
int fd;
static const char x = 'X';
r = sd_bus_message_read(m, "h", &fd);
if (r < 0) {
log_error_errno(r, "Failed to get parameter: %m");
goto fail;
}
log_info("Received fd=%d", fd);
if (write(fd, &x, 1) < 0) {
log_error_errno(errno, "Failed to write to fd: %m");
safe_close(fd);
goto fail;
}
r = sd_bus_reply_method_return(m, NULL);
if (r < 0) {
log_error_errno(r, "Failed to send reply: %m");
goto fail;
}
} else if (sd_bus_message_is_method_call(m, NULL, NULL)) {
r = sd_bus_reply_method_error(
m,
&SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_UNKNOWN_METHOD, "Unknown method."));
if (r < 0) {
log_error_errno(r, "Failed to send reply: %m");
goto fail;
}
}
}
r = 0;
fail:
if (bus) {
sd_bus_flush(bus);
sd_bus_unref(bus);
}
return r;
}
/*
This function communicates with the kernel to check whether or not it should
allow the access.
If the machine is in permissive mode it will return ok. Audit messages will
still be generated if the access would be denied in enforcing mode.
*/
int mac_selinux_generic_access_check(
sd_bus_message *message,
const char *path,
const char *permission,
sd_bus_error *error) {
_cleanup_(sd_bus_creds_unrefp) sd_bus_creds *creds = NULL;
const char *tclass = NULL, *scon = NULL;
struct audit_info audit_info = {};
_cleanup_free_ char *cl = NULL;
char *fcon = NULL;
char **cmdline = NULL;
int r = 0;
assert(message);
assert(permission);
assert(error);
r = access_init(error);
if (r <= 0)
return r;
r = sd_bus_query_sender_creds(
message,
SD_BUS_CREDS_PID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|
SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_AUDIT_LOGIN_UID|
SD_BUS_CREDS_SELINUX_CONTEXT|
SD_BUS_CREDS_AUGMENT /* get more bits from /proc */,
&creds);
if (r < 0)
goto finish;
/* The SELinux context is something we really should have
* gotten directly from the message or sender, and not be an
* augmented field. If it was augmented we cannot use it for
* authorization, since this is racy and vulnerable. Let's add
* an extra check, just in case, even though this really
* shouldn't be possible. */
assert_return((sd_bus_creds_get_augmented_mask(creds) & SD_BUS_CREDS_SELINUX_CONTEXT) == 0, -EPERM);
r = sd_bus_creds_get_selinux_context(creds, &scon);
if (r < 0)
goto finish;
if (path) {
/* Get the file context of the unit file */
r = getfilecon_raw(path, &fcon);
if (r < 0) {
r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get file context on %s.", path);
goto finish;
}
tclass = "service";
} else {
r = getcon_raw(&fcon);
if (r < 0) {
r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get current context.");
goto finish;
}
tclass = "system";
}
sd_bus_creds_get_cmdline(creds, &cmdline);
cl = strv_join(cmdline, " ");
audit_info.creds = creds;
audit_info.path = path;
audit_info.cmdline = cl;
r = selinux_check_access(scon, fcon, tclass, permission, &audit_info);
if (r < 0)
r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "SELinux policy denies access.");
log_debug("SELinux access check scon=%s tcon=%s tclass=%s perm=%s path=%s cmdline=%s: %i", scon, fcon, tclass, permission, path, cl, r);
finish:
freecon(fcon);
if (r < 0 && security_getenforce() != 1) {
sd_bus_error_free(error);
r = 0;
}
return r;
}
/*
This function communicates with the kernel to check whether or not it should
allow the access.
If the machine is in permissive mode it will return ok. Audit messages will
still be generated if the access would be denied in enforcing mode.
*/
int mac_selinux_generic_access_check(
sd_bus_message *message,
bool system,
const char *path,
const char *permission,
sd_bus_error *error) {
#ifdef HAVE_SELINUX
_cleanup_bus_creds_unref_ sd_bus_creds *creds = NULL;
const char *tclass = NULL, *scon = NULL;
struct audit_info audit_info = {};
_cleanup_free_ char *cl = NULL;
security_context_t fcon = NULL;
char **cmdline = NULL;
int r = 0;
assert(message);
assert(permission);
assert(error);
if (!mac_selinux_use())
return 0;
r = mac_selinux_access_init(error);
if (r < 0)
return r;
r = sd_bus_query_sender_creds(
message,
SD_BUS_CREDS_PID|SD_BUS_CREDS_EUID|SD_BUS_CREDS_EGID|
SD_BUS_CREDS_CMDLINE|SD_BUS_CREDS_AUDIT_LOGIN_UID|
SD_BUS_CREDS_SELINUX_CONTEXT|
SD_BUS_CREDS_AUGMENT /* get more bits from /proc */,
&creds);
if (r < 0)
goto finish;
r = sd_bus_creds_get_selinux_context(creds, &scon);
if (r < 0)
goto finish;
tclass = "service";
if (path && !system) {
/* Get the file context of the unit file */
r = getfilecon_raw(path, &fcon);
if (r < 0) {
r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get file context on %s.", path);
goto finish;
}
} else {
r = getcon_raw(&fcon);
if (r < 0) {
r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Failed to get current context.");
goto finish;
}
if (system)
tclass = "system";
}
sd_bus_creds_get_cmdline(creds, &cmdline);
cl = strv_join(cmdline, " ");
audit_info.creds = creds;
audit_info.path = path;
audit_info.cmdline = cl;
r = selinux_check_access(scon, fcon, tclass, permission, &audit_info);
if (r < 0)
r = sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "SELinux policy denies access.");
log_debug("SELinux access check scon=%s tcon=%s tclass=%s perm=%s path=%s cmdline=%s: %i", scon, fcon, tclass, permission, path, cl, r);
finish:
freecon(fcon);
if (r < 0 && security_getenforce() != 1) {
sd_bus_error_free(error);
r = 0;
}
return r;
#else
return 0;
#endif
}
