Add a test suite for validating SELinux labelling

There are many aspects of the guest XML which result in the
SELinux driver applying file labelling. With the increasing
configuration options it is desirable to test this behaviour.
It is not possible to assume that the test suite has the
ability to set SELinux labels. Most filesystems though will
support extended attributes. Thus for the purpose of testing,
it is possible to extend the existing LD_PRELOAD hack to
override setfilecon() and getfilecon() to simply use the
'user.libvirt.selinux' attribute for the sake of testing.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

.gitignore

@@ -158,6 +158,7 @@
 /tests/secaatest
 /tests/seclabeltest
 /tests/securityselinuxtest
+/tests/securityselinuxlabeltest
 /tests/sexpr2xmltest
 /tests/shunloadtest
 /tests/sockettest

HACKING

@@ -689,7 +689,7 @@ stick to the following general plan for all *.c source files:
   #include <string.h>
   #include <limits.h>
 
-  #if HAVE_NUMACTL                Some system includes aren't supported
+  #if WITH_NUMACTL                Some system includes aren't supported
   # include <numa.h>              everywhere so need these #if guards.
   #endif
 

cfg.mk

@@ -795,7 +795,7 @@ exclude_file_name_regexp--sc_prohibit_nonreentrant = \
   ^((po|tests)/|docs/.*py|run.in$$)
 
 exclude_file_name_regexp--sc_prohibit_raw_allocation = \
-  ^(src/util/viralloc\.[ch]|examples/.*)$$
+  ^(src/util/viralloc\.[ch]|examples/.*|tests/securityselinuxhelper.c)$$
 
 exclude_file_name_regexp--sc_prohibit_readlink = \
   ^src/(util/virutil|lxc/lxc_container)\.c$$

configure.ac

@@ -143,6 +143,7 @@ AC_MSG_RESULT([$VERSION_SCRIPT_FLAGS])
 LIBVIRT_COMPILE_WARNINGS
 
 LIBVIRT_CHECK_APPARMOR
+LIBVIRT_CHECK_ATTR
 LIBVIRT_CHECK_AUDIT
 LIBVIRT_CHECK_AVAHI
 LIBVIRT_CHECK_BLKID
@@ -2467,6 +2468,7 @@ AC_MSG_NOTICE([])
 AC_MSG_NOTICE([Libraries])
 AC_MSG_NOTICE([])
 LIBVIRT_RESULT_APPARMOR
+LIBVIRT_RESULT_ATTR
 LIBVIRT_RESULT_AUDIT
 LIBVIRT_RESULT_AVAHI
 LIBVIRT_RESULT_BLKID

libvirt.spec.in

@@ -410,6 +410,7 @@ BuildRequires: ncurses-devel
 BuildRequires: gettext
 BuildRequires: libtasn1-devel
 BuildRequires: gnutls-devel
+BuildRequires: libattr-devel
 %if 0%{?fedora} >= 12 || 0%{?rhel} >= 6
 # for augparse, optionally used in testing
 BuildRequires: augeas

m4/virt-attr.m4

+dnl The libattr.so library
+
+AC_DEFUN([LIBVIRT_CHECK_ATTR],[
+  LIBVIRT_CHECK_LIB([ATTR], [attr], [getxattr], [attr/xattr.h])
+])
+
+AC_DEFUN([LIBVIRT_RESULT_ATTR],[
+  LIBVIRT_RESULT_LIB([ATTR])
+])

tests/Makefile.am

@@ -68,6 +68,7 @@ EXTRA_DIST =		\
 	qemuxml2argvdata \
 	qemuxml2xmloutdata \
 	qemuxmlnsdata \
+	securityselinuxlabeldata \
 	schematestutils.sh \
 	sexpr2xmldata \
 	storagepoolschematest \
@@ -106,6 +107,9 @@ endif
 
 if WITH_SECDRIVER_SELINUX
 test_programs += securityselinuxtest
+if WITH_ATTR
+test_programs += securityselinuxlabeltest
+endif
 endif
 
 if WITH_DRIVER_MODULES
@@ -597,10 +601,20 @@ securityselinuxtest_SOURCES = \
 	securityselinuxtest.c testutils.h testutils.c
 securityselinuxtest_CFLAGS = -Dabs_builddir="\"$(abs_builddir)\"" $(AM_CFLAGS)
 securityselinuxtest_LDADD = $(LDADDS)
-securityselinuxtest_DEPENDENCIES = libsecurityselinuxhelper.la
-else
-EXTRA_DIST += securityselinuxtest.c securityselinuxhelper.c
+securityselinuxtest_DEPENDENCIES = libsecurityselinuxhelper.la ../src/libvirt.la
+
+if WITH_QEMU
+if WITH_ATTR
+securityselinuxlabeltest_SOURCES = \
+	securityselinuxlabeltest.c testutils.h testutils.c \
+        testutilsqemu.h testutilsqemu.c
+securityselinuxlabeltest_CFLAGS = -Dabs_builddir="\"$(abs_builddir)\"" $(AM_CFLAGS)
+securityselinuxlabeltest_LDADD = $(qemu_LDADDS)
+securityselinuxlabeltest_DEPENDENCIES = libsecurityselinuxhelper.la ../src/libvirt.la
+endif
+endif
 endif
+EXTRA_DIST += securityselinuxtest.c securityselinuxlabeltest.c securityselinuxhelper.c
 
 virbuftest_SOURCES = \
 	virbuftest.c testutils.h testutils.c

tests/securityselinuxhelper.c

@@ -24,6 +24,9 @@
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
+#include <attr/xattr.h>
+
+
 /*
  * The kernel policy will not allow us to arbitrarily change
  * test process context. This helper is used as an LD_PRELOAD
@@ -64,3 +67,33 @@ int setcon_raw(security_context_t context)
 {
     return setenv("FAKE_CONTEXT", context, 1);
 }
+
+
+#if WITH_ATTR
+int setfilecon(const char *path, security_context_t con)
+{
+    const char *constr = con;
+    return setxattr(path, "user.libvirt.selinux",
+                    constr, strlen(constr), 0);
+}
+
+
+int getfilecon(const char *path, security_context_t *con)
+{
+    char *constr = NULL;
+    ssize_t len = getxattr(path, "user.libvirt.selinux",
+                           NULL, 0);
+    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;
+}
+#endif

tests/securityselinuxlabeldata/chardev.txt

+/plain.txt;system_u:object_r:svirt_image_t:s0:c41,c264
+/plain.dev;system_u:object_r:svirt_image_t:s0:c41,c264
+/plain.fifo;system_u:object_r:svirt_image_t:s0:c41,c264
+/nolabel.sock;
+/plain.sock;
+/yeslabel.sock;system_u:object_r:svirt_image_t:s0:c41,c264
+/altlabel.sock;system_u:object_r:svirt_image_custom_t:s0:c41,c264

tests/securityselinuxlabeldata/chardev.xml

+<domain type='kvm'>
+  <name>vm1</name>
+  <uuid>c7b3edbd-edaf-9455-926a-d65c16db1800</uuid>
+  <memory unit='KiB'>219200</memory>
+  <os>
+    <type arch='i686' machine='pc-1.0'>hvm</type>
+    <boot dev='cdrom'/>
+  </os>
+  <devices>
+    <serial type='file'>
+      <source path='/plain.txt'/>
+    </serial>
+    <serial type='pipe'>
+      <source path='/plain.fifo'/>
+    </serial>
+    <serial type='dev'>
+      <source path='/plain.dev'/>
+    </serial>
+    <serial type='unix'>
+      <source mode='bind' path='/plain.sock'/>
+    </serial>
+    <serial type='unix'>
+      <source mode='connect' path='/nolabel.sock'>
+        <seclabel relabel='no' model='selinux'/>
+      </source>
+    </serial>
+    <serial type='unix'>
+      <source mode='connect' path='/yeslabel.sock'>
+      </source>
+    </serial>
+    <serial type='unix'>
+      <source mode='connect' path='/altlabel.sock'>
+        <seclabel relabel='yes' model='selinux'>
+          <label>system_u:object_r:svirt_image_custom_t:s0:c41,c264</label>
+        </seclabel>
+      </source>
+    </serial>
+    <input type='mouse' bus='ps2'/>
+    <graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'>
+      <listen type='address' address='0.0.0.0'/>
+    </graphics>
+  </devices>
+  <seclabel model="selinux" type="dynamic" relabel="yes">
+    <label>system_u:system_r:svirt_t:s0:c41,c264</label>
+    <imagelabel>system_u:object_r:svirt_image_t:s0:c41,c264</imagelabel>
+  </seclabel>
+</domain>

tests/securityselinuxlabeldata/disks.txt

+/plain.raw;system_u:object_r:svirt_image_t:s0:c41,c264
+/shared.raw;system_u:object_r:svirt_image_t:s0
+/readonly.raw;system_u:object_r:virt_content_t:s0
+/nolabel.raw;
+/altlabel.raw;system_u:object_r:svirt_image_custom_t:s0:c41,c264

tests/securityselinuxlabeldata/disks.xml

+<domain type='kvm'>
+  <name>vm1</name>
+  <uuid>c7b3edbd-edaf-9455-926a-d65c16db1800</uuid>
+  <memory unit='KiB'>219200</memory>
+  <os>
+    <type arch='i686' machine='pc-1.0'>hvm</type>
+    <boot dev='cdrom'/>
+  </os>
+  <devices>
+    <disk type='file' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source file='/plain.raw'/>
+      <target dev='vda' bus='virtio'/>
+    </disk>
+    <disk type='file' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source file='/shared.raw'/>
+      <shareable/>
+      <target dev='vdb' bus='virtio'/>
+    </disk>
+    <disk type='file' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source file='/readonly.raw'/>
+      <readonly/>
+      <target dev='vdc' bus='virtio'/>
+    </disk>
+    <disk type='file' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source file='/nolabel.raw'>
+        <seclabel model='selinux' relabel='no'/>
+      </source>
+      <target dev='vdd' bus='virtio'/>
+    </disk>
+    <disk type='file' device='disk'>
+      <driver name='qemu' type='raw'/>
+      <source file='/altlabel.raw'>
+        <seclabel model='selinux' relabel='yes'>
+          <label>system_u:object_r:svirt_image_custom_t:s0:c41,c264</label>
+        </seclabel>
+      </source>
+      <target dev='vde' bus='virtio'/>
+    </disk>
+    <input type='mouse' bus='ps2'/>
+    <graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'>
+      <listen type='address' address='0.0.0.0'/>
+    </graphics>
+  </devices>
+  <seclabel model="selinux" type="dynamic" relabel="yes">
+    <label>system_u:system_r:svirt_t:s0:c41,c264</label>
+    <imagelabel>system_u:object_r:svirt_image_t:s0:c41,c264</imagelabel>
+  </seclabel>
+</domain>

tests/securityselinuxlabeldata/kernel.txt

+/vmlinuz.raw;system_u:object_r:virt_content_t:s0
+/initrd.raw;system_u:object_r:virt_content_t:s0

tests/securityselinuxlabeldata/kernel.xml

+<domain type='kvm'>
+  <name>vm1</name>
+  <uuid>c7b3edbd-edaf-9455-926a-d65c16db1800</uuid>
+  <memory unit='KiB'>219200</memory>
+  <os>
+    <type arch='i686' machine='pc-1.0'>hvm</type>
+    <kernel>/vmlinuz.raw</kernel>
+    <initrd>/initrd.raw</initrd>
+  </os>
+  <devices>
+    <input type='mouse' bus='ps2'/>
+    <graphics type='vnc' port='-1' autoport='yes' listen='0.0.0.0'>
+      <listen type='address' address='0.0.0.0'/>
+    </graphics>
+  </devices>
+  <seclabel model="selinux" type="dynamic" relabel="yes">
+    <label>system_u:system_r:svirt_t:s0:c41,c264</label>
+    <imagelabel>system_u:object_r:svirt_image_t:s0:c41,c264</imagelabel>
+  </seclabel>
+</domain>

tests/securityselinuxlabeltest.c

+/*
+ * Copyright (C) 2011-2012 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, write to the Free Software
+ * License along with this library;  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#include <selinux/selinux.h>
+#include <selinux/context.h>
+
+#include "internal.h"
+#include "testutils.h"
+#include "testutilsqemu.h"
+#include "qemu/qemu_domain.h"
+#include "viralloc.h"
+#include "virerror.h"
+#include "virfile.h"
+#include "virlog.h"
+#include "virutil.h"
+#include "security/security_manager.h"
+
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+static virCapsPtr caps;
+
+static virSecurityManagerPtr mgr;
+
+typedef struct testSELinuxFile testSELinuxFile;
+
+struct testSELinuxFile {
+    char *file;
+    char *context;
+};
+
+
+static int
+testSELinuxMungePath(char **path)
+{
+    char *tmp;
+
+    if (virAsprintf(&tmp, "%s/securityselinuxlabeldata%s",
+                    abs_srcdir, *path) < 0) {
+        virReportOOMError();
+        return -1;
+    }
+
+    VIR_FREE(*path);
+    *path = tmp;
+    return 0;
+}
+
+static int
+testSELinuxLoadFileList(const char *testname,
+                        testSELinuxFile **files,
+                        size_t *nfiles)
+{
+    int ret = -1;
+    char *path = NULL;
+    FILE *fp = NULL;
+
+    *files = NULL;
+    *nfiles = 0;
+
+    if (virAsprintf(&path, "%s/securityselinuxlabeldata/%s.txt",
+                    abs_srcdir, testname) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+
+    if (!(fp = fopen(path, "r"))) {
+        goto cleanup;
+    }
+
+    while (!feof(fp)) {
+        char *line;
+        char *file, *context;
+        if (VIR_ALLOC_N(line, 1024) < 0) {
+            virReportOOMError();
+            goto cleanup;
+        }
+        if (!fgets(line, 1024, fp)) {
+            if (!feof(fp))
+                goto cleanup;
+            break;
+        }
+
+        char *tmp = strchr(line, ';');
+        *tmp = '\0';
+        tmp++;
+
+        if (virAsprintf(&file, "%s/securityselinuxlabeldata%s", abs_builddir, line) < 0) {
+            VIR_FREE(line);
+            virReportOOMError();
+            goto cleanup;
+        }
+        if (*tmp != '\0' && *tmp != '\n') {
+            if (!(context = strdup(tmp))) {
+                VIR_FREE(line);
+                VIR_FREE(file);
+                virReportOOMError();
+                goto cleanup;
+            }
+
+            tmp = strchr(context, '\n');
+            *tmp = '\0';
+        } else {
+            context = NULL;
+        }
+
+        if (VIR_EXPAND_N(*files, *nfiles, 1) < 0) {
+            virReportOOMError();
+            goto cleanup;
+        }
+
+        (*files)[(*nfiles)-1].file = file;
+        (*files)[(*nfiles)-1].context = context;
+    }
+
+    ret = 0;
+
+cleanup:
+    VIR_FORCE_FCLOSE(fp);
+    VIR_FREE(path);
+    return ret;
+}
+
+
+static virDomainDefPtr
+testSELinuxLoadDef(const char *testname)
+{
+    char *xmlfile = NULL;
+    char *xmlstr = NULL;
+    virDomainDefPtr def = NULL;
+    size_t i;
+
+    if (virAsprintf(&xmlfile, "%s/securityselinuxlabeldata/%s.xml",
+                    abs_srcdir, testname) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+
+    if (virFileReadAll(xmlfile, 1024*1024, &xmlstr) < 0) {
+        goto cleanup;
+    }
+
+    if (!(def = virDomainDefParseString(caps, xmlstr,
+                                        QEMU_EXPECTED_VIRT_TYPES,
+                                        0)))
+        goto cleanup;
+
+    for (i = 0 ; i < def->ndisks ; i++) {
+        if (def->disks[i]->type != VIR_DOMAIN_DISK_TYPE_FILE &&
+            def->disks[i]->type != VIR_DOMAIN_DISK_TYPE_BLOCK)
+            continue;
+
+        if (testSELinuxMungePath(&def->disks[i]->src) < 0)
+            goto cleanup;
+    }
+
+    for (i = 0 ; i < def->nserials ; i++) {
+        if (def->serials[i]->source.type != VIR_DOMAIN_CHR_TYPE_FILE &&
+            def->serials[i]->source.type != VIR_DOMAIN_CHR_TYPE_PIPE &&
+            def->serials[i]->source.type != VIR_DOMAIN_CHR_TYPE_DEV &&
+            def->serials[i]->source.type != VIR_DOMAIN_CHR_TYPE_UNIX)
+            continue;
+
+        if (def->serials[i]->source.type == VIR_DOMAIN_CHR_TYPE_UNIX) {
+            if (testSELinuxMungePath(&def->serials[i]->source.data.nix.path) < 0)
+                goto cleanup;
+        } else {
+            if (testSELinuxMungePath(&def->serials[i]->source.data.file.path) < 0)
+                goto cleanup;
+        }
+    }
+
+    if (def->os.kernel &&
+        testSELinuxMungePath(&def->os.kernel) < 0)
+        goto cleanup;
+    if (def->os.initrd &&
+        testSELinuxMungePath(&def->os.initrd) < 0)
+        goto cleanup;
+
+cleanup:
+    VIR_FREE(xmlfile);
+    VIR_FREE(xmlstr);
+    return def;
+}
+
+
+static int
+testSELinuxCreateDisks(testSELinuxFile *files, size_t nfiles)
+{
+    size_t i;
+
+    if (virFileMakePath(abs_builddir "/securityselinuxlabeldata") < 0)
+        return -1;
+
+    for (i = 0 ; i < nfiles ; i++) {
+        if (virFileTouch(files[i].file, 0600) < 0)
+            return -1;
+    }
+    return 0;
+}
+
+static int
+testSELinuxDeleteDisks(testSELinuxFile *files, size_t nfiles)
+{
+    size_t i;
+
+    for (i = 0 ; i < nfiles ; i++) {
+        if (unlink(files[i].file) < 0)
+            return -1;
+    }
+    return 0;
+}
+
+static int
+testSELinuxCheckLabels(testSELinuxFile *files, size_t nfiles)
+{
+    size_t i;
+    security_context_t ctx;
+
+    for (i = 0 ; i < nfiles ; i++) {
+        if (getfilecon(files[i].file, &ctx) < 0) {
+            if (errno == ENODATA) {
+                ctx = NULL;
+            } else {
+                virReportSystemError(errno,
+                                     "Cannot read label on %s",
+                                     files[i].file);
+                return -1;
+            }
+        }
+        if (!STREQ_NULLABLE(files[i].context, ctx)) {
+            virReportError(VIR_ERR_INTERNAL_ERROR,
+                           "File %s context '%s' did not match epected '%s'",
+                           files[i].file, ctx, files[i].context);
+            return -1;
+        }
+    }
+    return 0;
+}
+
+static int
+testSELinuxLabeling(const void *opaque)
+{
+    const char *testname = opaque;
+    int ret = -1;
+    testSELinuxFile *files = NULL;
+    size_t nfiles = 0;
+    size_t i;
+    virDomainDefPtr def = NULL;
+
+    if (testSELinuxLoadFileList(testname, &files, &nfiles) < 0)
+        goto cleanup;
+
+    if (testSELinuxCreateDisks(files, nfiles) < 0)
+        goto cleanup;
+
+    if (!(def = testSELinuxLoadDef(testname)))
+        goto cleanup;
+
+    if (virSecurityManagerSetAllLabel(mgr, def, NULL) < 0)
+        goto cleanup;
+
+    if (testSELinuxCheckLabels(files, nfiles) < 0)
+        goto cleanup;
+
+    ret = 0;
+
+cleanup:
+    if (testSELinuxDeleteDisks(files, nfiles) < 0)
+        goto cleanup;
+
+    virDomainDefFree(def);
+    for (i = 0 ; i < nfiles; i++) {
+        VIR_FREE(files[i].file);
+        VIR_FREE(files[i].context);
+    }
+    VIR_FREE(files);
+    return ret;
+}
+
+
+
+static int
+mymain(void)
+{
+    int ret = 0;
+
+    if (!(mgr = virSecurityManagerNew("selinux", "QEMU", false, true, false))) {
+        virErrorPtr err = virGetLastError();
+        if (err->code == VIR_ERR_CONFIG_UNSUPPORTED)
+            exit(EXIT_AM_SKIP);
+
+        fprintf(stderr, "Unable to initialize security driver: %s\n",
+                err->message);
+        exit(EXIT_FAILURE);
+    }
+
+    if ((caps = testQemuCapsInit()) == NULL)
+        exit(EXIT_FAILURE);
+
+#define DO_TEST_LABELING(name) \
+    if (virtTestRun("Labelling " # name, 1, testSELinuxLabeling, name) < 0) \
+        ret = -1;                                                       \
+
+    setcon((security_context_t)"system_r:system_u:libvirtd_t:s0:c0.c1023");
+
+    DO_TEST_LABELING("disks");
+    DO_TEST_LABELING("kernel");
+    DO_TEST_LABELING("chardev");
+
+    return (ret == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
+}
+
+VIRT_TEST_MAIN_PRELOAD(mymain, abs_builddir "/.libs/libsecurityselinuxhelper.so")