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socket: SELinux support for socket creation.

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It seems to work on my machine.

/proc/1/fd/20	system_u:system_r:system_dbusd_t:s0

/proc/1/fd/21	system_u:system_r:avahi_t:s0

And the AVC's seem to have dissapeared when a confined app trys to
connect to dbus or avahi.

If you run with this patch and selinux-policy-3.8.8-3.fc14.noarch
You should be able to boot in enforcing mode.
This commit is contained in:
Daniel J Walsh 2010-07-22 17:01:25 -04:00 committed by Lennart Poettering
parent 28322e1eb6
commit 7a58bfa4ae
5 changed files with 107 additions and 25 deletions
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3
Makefile.am
View file

@ -298,7 +298,8 @@ libsystemd_core_la_LIBADD = \
$(DBUS_LIBS) \
$(UDEV_LIBS) \
$(LIBWRAP_LIBS) \
$(PAM_LIBS)
$(PAM_LIBS) \
$(SELINUX_LIBS)
# This is needed because automake is buggy in how it generates the
# rules for C programs, but not Vala programs. We therefore can't

5
configure.ac
View file

@ -105,6 +105,11 @@ PKG_CHECK_MODULES(DBUS, [ dbus-1 >= 1.3.2 ])
AC_SUBST(DBUS_CFLAGS)
AC_SUBST(DBUS_LIBS)
PKG_CHECK_MODULES(SELINUX, [ libselinux ])
AC_SUBST(SELINUX_CFLAGS)
AC_SUBST(SELINUX_LIBS)
AC_SEARCH_LIBS([is_selinux_enabled], [selinux], [], [AC_MSG_ERROR([*** libselinux library not found])])
PKG_CHECK_MODULES(DBUSGLIB, [ dbus-glib-1 ])
AC_SUBST(DBUSGLIB_CFLAGS)
AC_SUBST(DBUSGLIB_LIBS)

19
src/socket-util.c
View file

@ -29,6 +29,7 @@
#include <net/if.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <selinux/selinux.h>
#include "macro.h"
#include "util.h"
@ -305,7 +306,7 @@ int socket_address_listen(
bool free_bind,
mode_t directory_mode,
mode_t socket_mode,
/* FIXME SELINUX: pass SELinux context object here */
security_context_t scon,
int *ret) {
int r, fd, one;
@ -315,11 +316,19 @@ int socket_address_listen(
if ((r = socket_address_verify(a)) < 0)
return r;
/* FIXME SELINUX: The socket() here should be done with the
* right SELinux context set */
if (setsockcreatecon(scon) < 0) {
log_error("Failed to set SELinux context (%s) on socket: %m", scon);
if (security_getenforce() == 1)
return -errno;
}
if ((fd = socket(socket_address_family(a), a->type | SOCK_NONBLOCK | SOCK_CLOEXEC, 0)) < 0)
return -errno;
fd = socket(socket_address_family(a), a->type | SOCK_NONBLOCK | SOCK_CLOEXEC, 0);
r = fd < 0 ? -errno : 0;
setsockcreatecon(NULL);
if (r < 0)
return r;
if (socket_address_family(a) == AF_INET6 && only != SOCKET_ADDRESS_DEFAULT) {
int flag = only == SOCKET_ADDRESS_IPV6_ONLY;

3
src/socket-util.h
View file

@ -26,6 +26,7 @@
#include <netinet/in.h>
#include <sys/un.h>
#include <net/if.h>
#include <selinux/selinux.h>
#include "macro.h"
#include "util.h"
@ -71,7 +72,7 @@ int socket_address_listen(
bool free_bind,
mode_t directory_mode,
mode_t socket_mode,
/* FIXME SELINUX: pass SELinux context object here */
security_context_t scon,
int *ret);
bool socket_address_is(const SocketAddress *a, const char *s, int type);

102
src/socket.c
View file

@ -27,6 +27,7 @@
#include <sys/epoll.h>
#include <signal.h>
#include <arpa/inet.h>
#include <selinux/selinux.h>
#include "unit.h"
#include "socket.h"
@ -642,24 +643,89 @@ static void socket_apply_fifo_options(Socket *s, int fd) {
log_warning("F_SETPIPE_SZ: %m");
}
static int selinux_getconfromexe(
const char *exe,
security_context_t *newcon) {
security_context_t mycon = NULL, fcon = NULL;
security_class_t sclass;
int r = 0;
r = getcon(&mycon);
if (r < 0)
goto fail;
r = getfilecon(exe, &fcon);
if (r < 0)
goto fail;
sclass = string_to_security_class("process");
r = security_compute_create(mycon, fcon, sclass, newcon);
fail:
if (r < 0)
r = -errno;
freecon(mycon);
freecon(fcon);
return r;
}
static int selinux_getfileconfrompath(
const security_context_t scon,
const char *path,
const char *class,
security_context_t *fcon) {
security_context_t dir_con = NULL;
security_class_t sclass;
int r = 0;
r = getfilecon(path, &dir_con);
if (r >= 0) {
r = -1;
if ((sclass = string_to_security_class(class)) != 0)
r = security_compute_create(scon, dir_con, sclass, fcon);
}
if (r < 0)
r = -errno;
freecon(dir_con);
return r;
}
static int fifo_address_create(
const char *path,
mode_t directory_mode,
mode_t socket_mode,
/* FIXME SELINUX: pass SELinux context object here */
security_context_t scon,
int *_fd) {
int fd = -1, r;
int fd = -1, r = 0;
struct stat st;
mode_t old_mask;
security_context_t filecon = NULL;
assert(path);
assert(_fd);
mkdir_parents(path, directory_mode);
/* FIXME SELINUX: The mkfifo here should be done with
* the right SELinux context set */
if (scon) {
if (scon && ((r = selinux_getfileconfrompath(scon, path, "fifo_file", &filecon)) == 0)) {
r = setfscreatecon(filecon);
if (r < 0) {
log_error("Failed to set SELinux file context (%s) on %s: %m", scon, path);
r = -errno;
}
freecon(filecon);
}
if (r < 0 && security_getenforce() == 1)
goto fail;
}
/* Enforce the right access mode for the fifo */
old_mask = umask(~ socket_mode);
@ -680,6 +746,8 @@ static int fifo_address_create(
goto fail;
}
setfscreatecon(NULL);
if (fstat(fd, &st) < 0) {
r = -errno;
goto fail;
@ -698,6 +766,7 @@ static int fifo_address_create(
return 0;
fail:
setfscreatecon(NULL);
if (fd >= 0)
close_nointr_nofail(fd);
@ -707,25 +776,20 @@ fail:
static int socket_open_fds(Socket *s) {
SocketPort *p;
int r;
security_context_t scon = NULL;
assert(s);
/* FIXME SELINUX: Somewhere here we must set the the SELinux
context for the created sockets and FIFOs. To figure out
the executable name for this, use
socket_instantiate_service() and then access the executable
path name via
s->service->exec_command[SERVICE_EXEC_START]->path. Example:
if ((r = socket_instantiate_service(s)) < 0)
return r;
log_debug("Socket unit %s will spawn service unit %s with executable path %s.",
s->meta.id,
s->service->meta.id,
s->service->exec_command[SERVICE_EXEC_START]->path);
*/
if (selinux_getconfromexe(s->service->exec_command[SERVICE_EXEC_START]->path, &scon) < 0) {
log_error("Failed to get SELinux exec context for %s \n", s->service->exec_command[SERVICE_EXEC_START]->path);
if (security_getenforce() == 1)
return -errno;
}
log_debug("SELinux Socket context for %s set to %s\n", s->service->exec_command[SERVICE_EXEC_START]->path, scon);
LIST_FOREACH(port, p, s->ports) {
if (p->fd >= 0)
@ -741,7 +805,7 @@ static int socket_open_fds(Socket *s) {
s->free_bind,
s->directory_mode,
s->socket_mode,
/* FIXME SELINUX: Pass the SELinux context object here */
scon,
&p->fd)) < 0)
goto rollback;
@ -753,7 +817,7 @@ static int socket_open_fds(Socket *s) {
p->path,
s->directory_mode,
s->socket_mode,
/* FIXME SELINUX: Pass the SELinux context object here */
scon,
&p->fd)) < 0)
goto rollback;
@ -763,10 +827,12 @@ static int socket_open_fds(Socket *s) {
assert_not_reached("Unknown port type");
}
freecon(scon);
return 0;
rollback:
socket_close_fds(s);
freecon(scon);
return r;
}