libvirt/tests/securityselinuxhelper.c
Michal Privoznik e71e13488d Substitute security_context_t with char *
Historically, we've used security_context_t for variables passed
to libselinux APIs. But almost 7 years ago, libselinux developers
admitted in their API that in fact, it's just a 'char *' type
[1]. Ever since then the APIs accept 'char *' instead, but they
kept the old alias just for API stability. Well, not anymore [2].

1: 9eb9c93275
2: 7a124ca275

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
2020-07-15 14:31:07 +02:00

324 lines
7.7 KiB
C

/*
* Copyright (C) 2011-2013, 2016 Red Hat, Inc.
*
* This library 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.
*
* This library 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 this library. If not, see
* <http://www.gnu.org/licenses/>.
*
*/
#include <config.h>
/* This file is only compiled on Linux, and only if xattr support was
* detected. */
#include "virmock.h"
#if HAVE_LINUX_MAGIC_H
# include <linux/magic.h>
#endif
#include <selinux/selinux.h>
#include <selinux/label.h>
#include <sys/vfs.h>
#include <unistd.h>
#include <sys/xattr.h>
#ifndef NFS_SUPER_MAGIC
# define NFS_SUPER_MAGIC 0x6969
#endif
#define VIR_FROM_THIS VIR_FROM_NONE
#include "viralloc.h"
#include "virstring.h"
static int (*real_statfs)(const char *path, struct statfs *buf);
static int (*real_security_get_boolean_active)(const char *name);
static int (*real_is_selinux_enabled)(void);
static const char *(*real_selinux_virtual_domain_context_path)(void);
static const char *(*real_selinux_virtual_image_context_path)(void);
static const char *(*real_selinux_lxc_contexts_path)(void);
static struct selabel_handle *(*real_selabel_open)(unsigned int backend,
const struct selinux_opt *opts,
unsigned nopts);
static void (*real_selabel_close)(struct selabel_handle *handle);
static int (*real_selabel_lookup_raw)(struct selabel_handle *handle,
char **con,
const char *key,
int type);
static void init_syms(void)
{
if (real_statfs)
return;
VIR_MOCK_REAL_INIT(statfs);
VIR_MOCK_REAL_INIT(security_get_boolean_active);
VIR_MOCK_REAL_INIT(is_selinux_enabled);
VIR_MOCK_REAL_INIT(selinux_virtual_domain_context_path);
VIR_MOCK_REAL_INIT(selinux_virtual_image_context_path);
VIR_MOCK_REAL_INIT(selinux_lxc_contexts_path);
VIR_MOCK_REAL_INIT(selabel_open);
VIR_MOCK_REAL_INIT(selabel_close);
VIR_MOCK_REAL_INIT(selabel_lookup_raw);
}
/*
* The kernel policy will not allow us to arbitrarily change
* test process context. This helper is used as an LD_PRELOAD
* so that the libvirt code /thinks/ it is changing/reading
* the process context, whereas in fact we're faking it all.
* Furthermore, we fake out that we are using an nfs subdirectory,
* where we control whether selinux is enforcing and whether
* the virt_use_nfs bool is set.
*/
int getcon_raw(char **context)
{
if (!is_selinux_enabled()) {
errno = EINVAL;
return -1;
}
if (getenv("FAKE_SELINUX_CONTEXT") == NULL) {
*context = NULL;
errno = EINVAL;
return -1;
}
*context = g_strdup(getenv("FAKE_SELINUX_CONTEXT"));
return 0;
}
int getcon(char **context)
{
return getcon_raw(context);
}
int getpidcon_raw(pid_t pid, char **context)
{
if (!is_selinux_enabled()) {
errno = EINVAL;
return -1;
}
if (pid != getpid()) {
*context = NULL;
errno = ESRCH;
return -1;
}
if (getenv("FAKE_SELINUX_CONTEXT") == NULL) {
*context = NULL;
errno = EINVAL;
return -1;
}
*context = g_strdup(getenv("FAKE_SELINUX_CONTEXT"));
return 0;
}
int getpidcon(pid_t pid, char **context)
{
return getpidcon_raw(pid, context);
}
int setcon_raw(const char *context)
{
if (!is_selinux_enabled()) {
errno = EINVAL;
return -1;
}
return g_setenv("FAKE_SELINUX_CONTEXT", context, TRUE);
}
int setcon(const char *context)
{
return setcon_raw(context);
}
int setfilecon_raw(const char *path, const char *con)
{
const char *constr = con;
if (STRPREFIX(path, abs_builddir "/securityselinuxlabeldata/nfs/")) {
errno = EOPNOTSUPP;
return -1;
}
return setxattr(path, "user.libvirt.selinux",
constr, strlen(constr), 0);
}
int setfilecon(const char *path, const char *con)
{
return setfilecon_raw(path, con);
}
int getfilecon_raw(const char *path, char **con)
{
char *constr = NULL;
ssize_t len = getxattr(path, "user.libvirt.selinux",
NULL, 0);
if (STRPREFIX(path, abs_builddir "/securityselinuxlabeldata/nfs/")) {
errno = EOPNOTSUPP;
return -1;
}
if (len < 0)
return -1;
if (!(constr = malloc(len+1)))
return -1;
memset(constr, 0, len);
if (getxattr(path, "user.libvirt.selinux", constr, len) < 0) {
free(constr);
return -1;
}
*con = constr;
constr[len] = '\0';
return 0;
}
int getfilecon(const char *path, char **con)
{
return getfilecon_raw(path, con);
}
int statfs(const char *path, struct statfs *buf)
{
int ret;
init_syms();
ret = real_statfs(path, buf);
if (!ret && STREQ(path, abs_builddir "/securityselinuxlabeldata/nfs"))
buf->f_type = NFS_SUPER_MAGIC;
return ret;
}
int is_selinux_enabled(void)
{
return getenv("FAKE_SELINUX_DISABLED") == NULL;
}
int security_disable(void)
{
if (!is_selinux_enabled()) {
errno = ENOENT;
return -1;
}
return g_setenv("FAKE_SELINUX_DISABLED", "1", TRUE);
}
int security_getenforce(void)
{
if (!is_selinux_enabled()) {
errno = ENOENT;
return -1;
}
/* For the purpose of our test, we are enforcing. */
return 1;
}
int security_get_boolean_active(const char *name)
{
if (!is_selinux_enabled()) {
errno = ENOENT;
return -1;
}
/* For the purpose of our test, nfs is not permitted. */
if (STREQ(name, "virt_use_nfs"))
return 0;
init_syms();
return real_security_get_boolean_active(name);
}
const char *selinux_virtual_domain_context_path(void)
{
init_syms();
if (real_is_selinux_enabled())
return real_selinux_virtual_domain_context_path();
return abs_srcdir "/securityselinuxhelperdata/virtual_domain_context";
}
const char *selinux_virtual_image_context_path(void)
{
init_syms();
if (real_is_selinux_enabled())
return real_selinux_virtual_image_context_path();
return abs_srcdir "/securityselinuxhelperdata/virtual_image_context";
}
const char *selinux_lxc_contexts_path(void)
{
init_syms();
if (real_is_selinux_enabled())
return real_selinux_lxc_contexts_path();
return abs_srcdir "/securityselinuxhelperdata/lxc_contexts";
}
struct selabel_handle *
selabel_open(unsigned int backend,
const struct selinux_opt *opts,
unsigned nopts)
{
char *fake_handle;
init_syms();
if (real_is_selinux_enabled())
return real_selabel_open(backend, opts, nopts);
/* struct selabel_handle is opaque; fake it */
if (VIR_ALLOC(fake_handle) < 0)
return NULL;
return (struct selabel_handle *)fake_handle;
}
void selabel_close(struct selabel_handle *handle)
{
init_syms();
if (real_is_selinux_enabled())
return real_selabel_close(handle);
VIR_FREE(handle);
}
int selabel_lookup_raw(struct selabel_handle *handle,
char **con,
const char *key,
int type)
{
init_syms();
if (real_is_selinux_enabled())
return real_selabel_lookup_raw(handle, con, key, type);
/* Unimplemented */
errno = ENOENT;
return -1;
}