mirror of
https://gitlab.com/libvirt/libvirt.git
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ba1a91cd1f
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
198 lines
4.9 KiB
C
198 lines
4.9 KiB
C
/*
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* Copyright (C) 2011-2013 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library. If not, see
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* <http://www.gnu.org/licenses/>.
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*
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*/
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#include <config.h>
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/* This file is only compiled on Linux, and only if xattr support was
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* detected. */
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#include <dlfcn.h>
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#include <errno.h>
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#if HAVE_LINUX_MAGIC_H
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# include <linux/magic.h>
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#endif
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#include <selinux/selinux.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/vfs.h>
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#include <unistd.h>
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#include <attr/xattr.h>
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#ifndef NFS_SUPER_MAGIC
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# define NFS_SUPER_MAGIC 0x6969
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#endif
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#include "virstring.h"
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static int (*realstatfs)(const char *path, struct statfs *buf);
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static int (*realsecurity_get_boolean_active)(const char *name);
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static void init_syms(void)
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{
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if (realstatfs)
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return;
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#define LOAD_SYM(name) \
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do { \
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if (!(real ## name = dlsym(RTLD_NEXT, #name))) { \
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fprintf(stderr, "Cannot find real '%s' symbol\n", #name); \
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abort(); \
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} \
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} while (0)
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LOAD_SYM(statfs);
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LOAD_SYM(security_get_boolean_active);
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#undef LOAD_SYM
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}
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/*
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* The kernel policy will not allow us to arbitrarily change
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* test process context. This helper is used as an LD_PRELOAD
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* so that the libvirt code /thinks/ it is changing/reading
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* the process context, whereas in fact we're faking it all.
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* Furthermore, we fake out that we are using an nfs subdirectory,
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* where we control whether selinux is enforcing and whether
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* the virt_use_nfs bool is set.
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*/
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int getcon_raw(security_context_t *context)
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{
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if (getenv("FAKE_CONTEXT") == NULL) {
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*context = NULL;
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errno = EINVAL;
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return -1;
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}
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return VIR_STRDUP_QUIET(*context, getenv("FAKE_CONTEXT"));
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}
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int getcon(security_context_t *context)
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{
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return getcon_raw(context);
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}
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int getpidcon_raw(pid_t pid, security_context_t *context)
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{
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if (pid != getpid()) {
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*context = NULL;
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errno = ESRCH;
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return -1;
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}
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if (getenv("FAKE_CONTEXT") == NULL) {
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*context = NULL;
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errno = EINVAL;
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return -1;
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}
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return VIR_STRDUP_QUIET(*context, getenv("FAKE_CONTEXT"));
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}
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int getpidcon(pid_t pid, security_context_t *context)
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{
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return getpidcon_raw(pid, context);
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}
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int setcon_raw(security_context_t context)
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{
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return setenv("FAKE_CONTEXT", context, 1);
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}
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int setcon(security_context_t context)
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{
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return setcon_raw(context);
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}
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int setfilecon_raw(const char *path, security_context_t con)
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{
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const char *constr = con;
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if (STRPREFIX(path, abs_builddir "/securityselinuxlabeldata/nfs/")) {
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errno = EOPNOTSUPP;
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return -1;
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}
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return setxattr(path, "user.libvirt.selinux",
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constr, strlen(constr), 0);
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}
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int setfilecon(const char *path, security_context_t con)
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{
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return setfilecon_raw(path, con);
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}
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int getfilecon_raw(const char *path, security_context_t *con)
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{
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char *constr = NULL;
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ssize_t len = getxattr(path, "user.libvirt.selinux",
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NULL, 0);
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if (STRPREFIX(path, abs_builddir "/securityselinuxlabeldata/nfs/")) {
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errno = EOPNOTSUPP;
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return -1;
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}
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if (len < 0)
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return -1;
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if (!(constr = malloc(len+1)))
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return -1;
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memset(constr, 0, len);
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if (getxattr(path, "user.libvirt.selinux", constr, len) < 0) {
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free(constr);
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return -1;
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}
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*con = constr;
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constr[len] = '\0';
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return 0;
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}
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int getfilecon(const char *path, security_context_t *con)
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{
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return getfilecon_raw(path, con);
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}
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int statfs(const char *path, struct statfs *buf)
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{
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int ret;
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init_syms();
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ret = realstatfs(path, buf);
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if (!ret && STREQ(path, abs_builddir "/securityselinuxlabeldata/nfs"))
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buf->f_type = NFS_SUPER_MAGIC;
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return ret;
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}
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int security_getenforce(void)
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{
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/* For the purpose of our test, we are enforcing. */
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return 1;
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}
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int security_get_boolean_active(const char *name)
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{
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/* For the purpose of our test, nfs is not permitted. */
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if (STREQ(name, "virt_use_nfs"))
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return 0;
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init_syms();
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return realsecurity_get_boolean_active(name);
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}
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