[PATCH-v4 1/2] systemd: mount the securityfs filesystem at early stage

[PATCH-v4 1/2] systemd: mount the securityfs filesystem at early stage

[Roberto Sassu]

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The mount of the securityfs filesystem is now performed in the main systemd
executable as it is used by IMA to provide the interface for loading custom
policies. The unit file 'units/sys-kernel-security.mount' has been removed
because it is not longer necessary.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Acked-by: Gianluca Ramunno <ramunno@polito.it>
---
 Makefile.am                     |    3 ---
 src/mount-setup.c               |    6 ++++--
 units/sys-kernel-security.mount |   17 -----------------
 3 files changed, 4 insertions(+), 22 deletions(-)
 delete mode 100644 units/sys-kernel-security.mount

diff --git a/Makefile.am b/Makefile.am
index d2bd340..c0fcd70 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -291,7 +291,6 @@ dist_systemunit_DATA = \
 	units/dev-mqueue.mount \
 	units/sys-kernel-config.mount \
 	units/sys-kernel-debug.mount \
-	units/sys-kernel-security.mount \
 	units/sys-fs-fuse-connections.mount \
 	units/var-run.mount \
 	units/media.mount \
@@ -2342,7 +2341,6 @@ systemd-install-data-hook:
 			dev-mqueue.mount \
 			sys-kernel-config.mount \
 			sys-kernel-debug.mount \
-			sys-kernel-security.mount \
 			sys-fs-fuse-connections.mount \
 			systemd-modules-load.service \
 			systemd-tmpfiles-setup.service \
@@ -2352,7 +2350,6 @@ systemd-install-data-hook:
 		$(LN_S) ../dev-mqueue.mount dev-mqueue.mount && \
 		$(LN_S) ../sys-kernel-config.mount sys-kernel-config.mount && \
 		$(LN_S) ../sys-kernel-debug.mount sys-kernel-debug.mount && \
-		$(LN_S) ../sys-kernel-security.mount sys-kernel-security.mount && \
 		$(LN_S) ../sys-fs-fuse-connections.mount sys-fs-fuse-connections.mount && \
 		$(LN_S) ../systemd-modules-load.service systemd-modules-load.service && \
 		$(LN_S) ../systemd-tmpfiles-setup.service systemd-tmpfiles-setup.service && \
diff --git a/src/mount-setup.c b/src/mount-setup.c
index 7c14ea8..aaffb65 100644
--- a/src/mount-setup.c
+++ b/src/mount-setup.c
@@ -51,13 +51,15 @@ typedef struct MountPoint {
 } MountPoint;
 
 /* The first three entries we might need before SELinux is up. The
- * other ones we can delay until SELinux is loaded. */
-#define N_EARLY_MOUNT 3
+ * fourth (securityfs) is needed by IMA to load a custom policy. The
+ * other ones we can delay until SELinux and IMA are loaded. */
+#define N_EARLY_MOUNT 4
 
 static const MountPoint mount_table[] = {
         { "proc",     "/proc",                  "proc",     NULL,                MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
         { "sysfs",    "/sys",                   "sysfs",    NULL,                MS_NOSUID|MS_NOEXEC|MS_NODEV, true },
         { "devtmpfs", "/dev",                   "devtmpfs", "mode=755",          MS_NOSUID,                    true },
+        { "securityfs", "/sys/kernel/security", "securityfs", NULL,              MS_NOSUID|MS_NOEXEC|MS_NODEV, false },
         { "tmpfs",    "/dev/shm",               "tmpfs",    "mode=1777",         MS_NOSUID|MS_NODEV,           true },
         { "devpts",   "/dev/pts",               "devpts",   "mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC, false },
         { "tmpfs",    "/run",                   "tmpfs",    "mode=755",          MS_NOSUID|MS_NODEV, true },
diff --git a/units/sys-kernel-security.mount b/units/sys-kernel-security.mount
deleted file mode 100644
index 80cd761..0000000
--- a/units/sys-kernel-security.mount
+++ /dev/null
@@ -1,17 +0,0 @@
-#  This file is part of systemd.
-#
-#  systemd is free software; you can redistribute it and/or modify it
-#  under the terms of the GNU General Public License as published by
-#  the Free Software Foundation; either version 2 of the License, or
-#  (at your option) any later version.
-
-[Unit]
-Description=Security File System
-DefaultDependencies=no
-ConditionPathExists=/sys/kernel/security
-Before=sysinit.target
-
-[Mount]
-What=securityfs
-Where=/sys/kernel/security
-Type=securityfs
-- 
1.7.7.6


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[PATCH-v4 2/2] main: added support for loading IMA custom policies

[Roberto Sassu]

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The new function ima_setup() loads an IMA custom policy from a file in the
default location '/etc/ima/ima-policy', if present, and writes it to the
path 'ima/policy' in the security filesystem. This function is executed
at early stage in order to avoid that some file operations are not measured
by IMA and it is placed after the initialization of SELinux because IMA
needs the latter (or other security modules) to understand LSM-specific
rules. This feature is enabled by default and can be disabled by providing
the option '--disable-ima' to the configure script.

Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
Acked-by: Gianluca Ramunno <ramunno@polito.it>
---
 Makefile.am     |    1 +
 configure.ac    |   14 +++++++
 src/build.h     |    8 +++-
 src/ima-setup.c |  115 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/ima-setup.h |   29 ++++++++++++++
 src/main.c      |    6 ++-
 6 files changed, 171 insertions(+), 2 deletions(-)
 create mode 100644 src/ima-setup.c
 create mode 100644 src/ima-setup.h

diff --git a/Makefile.am b/Makefile.am
index c0fcd70..08c7ea7 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -516,6 +516,7 @@ libsystemd_core_la_SOURCES = \
 	src/mount-setup.c \
 	src/hostname-setup.c \
 	src/selinux-setup.c \
+	src/ima-setup.c \
 	src/loopback-setup.c \
 	src/kmod-setup.c \
 	src/locale-setup.c \
diff --git a/configure.ac b/configure.ac
index 3860088..b562078 100644
--- a/configure.ac
+++ b/configure.ac
@@ -127,6 +127,19 @@ PKG_CHECK_MODULES(UDEV, [ libudev >= 172 ])
 PKG_CHECK_MODULES(DBUS, [ dbus-1 >= 1.3.2 ])
 PKG_CHECK_MODULES(KMOD, [ libkmod >= 5 ])
 
+have_ima=yes
+AC_ARG_ENABLE([ima], AS_HELP_STRING([--disable-ima],[Disable optional IMA support]),
+                [case "${enableval}" in
+                        yes) have_ima=yes ;;
+                        no) have_ima=no ;;
+                        *) AC_MSG_ERROR(bad value ${enableval} for --disable-ima) ;;
+                esac],
+                [have_ima=yes])
+
+if test "x${have_ima}" != xno ; then
+        AC_DEFINE(HAVE_IMA, 1, [Define if IMA is available])
+fi
+
 have_selinux=no
 AC_ARG_ENABLE(selinux, AS_HELP_STRING([--disable-selinux], [Disable optional SELINUX support]))
 if test "x$enable_selinux" != "xno"; then
@@ -629,6 +642,7 @@ AC_MSG_RESULT([
         tcpwrap:                 ${have_tcpwrap}
         PAM:                     ${have_pam}
         AUDIT:                   ${have_audit}
+        IMA:                     ${have_ima}
         SELinux:                 ${have_selinux}
         XZ:                      ${have_xz}
         ACL:                     ${have_acl}
diff --git a/src/build.h b/src/build.h
index 50cd79d..0619013 100644
--- a/src/build.h
+++ b/src/build.h
@@ -46,6 +46,12 @@
 #define _SELINUX_FEATURE_ "-SELINUX"
 #endif
 
+#ifdef HAVE_IMA
+#define _IMA_FEATURE_ "+IMA"
+#else
+#define _IMA_FEATURE_ "-IMA"
+#endif
+
 #ifdef HAVE_SYSV_COMPAT
 #define _SYSVINIT_FEATURE_ "+SYSVINIT"
 #else
@@ -58,6 +64,6 @@
 #define _LIBCRYPTSETUP_FEATURE_ "-LIBCRYPTSETUP"
 #endif
 
-#define SYSTEMD_FEATURES _PAM_FEATURE_ " " _LIBWRAP_FEATURE_ " " _AUDIT_FEATURE_ " " _SELINUX_FEATURE_ " " _SYSVINIT_FEATURE_ " " _LIBCRYPTSETUP_FEATURE_
+#define SYSTEMD_FEATURES _PAM_FEATURE_ " " _LIBWRAP_FEATURE_ " " _AUDIT_FEATURE_ " " _SELINUX_FEATURE_ " " _IMA_FEATURE_ " " _SYSVINIT_FEATURE_ " " _LIBCRYPTSETUP_FEATURE_
 
 #endif
diff --git a/src/ima-setup.c b/src/ima-setup.c
new file mode 100644
index 0000000..03e43dc
--- /dev/null
+++ b/src/ima-setup.c
@@ -0,0 +1,115 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+  Copyright (C) 2012 Roberto Sassu - Politecnico di Torino, Italy
+                                     TORSEC group -- http://security.polito.it
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+#include "ima-setup.h"
+#include "mount-setup.h"
+#include "macro.h"
+#include "util.h"
+#include "log.h"
+#include "label.h"
+
+#define IMA_SECFS_DIR "/sys/kernel/security/ima"
+#define IMA_SECFS_POLICY IMA_SECFS_DIR "/policy"
+#define IMA_POLICY_PATH "/etc/ima/ima-policy"
+
+int ima_setup(void) {
+
+#ifdef HAVE_IMA
+       struct stat st;
+       ssize_t policy_size = 0, written = 0;
+       char *policy;
+       int policyfd = -1, imafd = -1;
+       int result = 0;
+
+#ifndef HAVE_SELINUX
+       /* Mount the securityfs filesystem */
+       mount_setup_early();
+#endif
+
+       if (stat(IMA_POLICY_PATH, &st) < 0)
+               return 0;
+
+       policy_size = st.st_size;
+       if (stat(IMA_SECFS_DIR, &st) < 0) {
+               log_debug("IMA support is disabled in the kernel, ignoring.");
+               return 0;
+       }
+
+       if (stat(IMA_SECFS_POLICY, &st) < 0) {
+               log_error("Another IMA custom policy has already been loaded, "
+                         "ignoring.");
+               return 0;
+       }
+
+       policyfd = open(IMA_POLICY_PATH, O_RDONLY|O_CLOEXEC);
+       if (policyfd < 0) {
+               log_error("Failed to open the IMA custom policy file %s (%m), "
+                         "ignoring.", IMA_POLICY_PATH);
+               return 0;
+       }
+
+       imafd = open(IMA_SECFS_POLICY, O_WRONLY|O_CLOEXEC);
+       if (imafd < 0) {
+               log_error("Failed to open the IMA kernel interface %s (%m), "
+                         "ignoring.", IMA_SECFS_POLICY);
+               goto out;
+       }
+
+       policy = mmap(NULL, policy_size, PROT_READ, MAP_PRIVATE, policyfd, 0);
+       if (policy == MAP_FAILED) {
+               log_error("mmap() failed (%m), freezing");
+               result = -errno;
+               goto out;
+       }
+
+       written = loop_write(imafd, policy, (size_t)policy_size, false);
+       if (written != policy_size) {
+               log_error("Failed to load the IMA custom policy file %s (%m), "
+                         "ignoring.", IMA_POLICY_PATH);
+               goto out_mmap;
+       }
+
+       log_info("Successfully loaded the IMA custom policy %s.",
+                IMA_POLICY_PATH);
+out_mmap:
+       munmap(policy, policy_size);
+out:
+       if (policyfd >= 0)
+                close_nointr_nofail(policyfd);
+       if (imafd >= 0)
+                close_nointr_nofail(imafd);
+       if (result)
+                return result;
+#endif /* HAVE_IMA */
+
+       return 0;
+}
diff --git a/src/ima-setup.h b/src/ima-setup.h
new file mode 100644
index 0000000..7d677cf
--- /dev/null
+++ b/src/ima-setup.h
@@ -0,0 +1,29 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#ifndef fooimasetuphfoo
+#define fooimasetuphfoo
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+  Copyright (C) 2012 Roberto Sassu - Politecnico di Torino, Italy
+                                     TORSEC group -- http://security.polito.it
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+int ima_setup(void);
+
+#endif
diff --git a/src/main.c b/src/main.c
index ed317b4..7ae8841 100644
--- a/src/main.c
+++ b/src/main.c
@@ -41,6 +41,7 @@
 #include "kmod-setup.h"
 #include "locale-setup.h"
 #include "selinux-setup.h"
+#include "ima-setup.h"
 #include "machine-id-setup.h"
 #include "load-fragment.h"
 #include "fdset.h"
@@ -1203,9 +1204,12 @@ int main(int argc, char *argv[]) {
                 arg_running_as = MANAGER_SYSTEM;
                 log_set_target(detect_container(NULL) > 0 ? LOG_TARGET_CONSOLE : LOG_TARGET_JOURNAL_OR_KMSG);
 
-                if (!is_reexec)
+                if (!is_reexec) {
                         if (selinux_setup(&loaded_policy) < 0)
                                 goto finish;
+                        if (ima_setup() < 0)
+                                goto finish;
+                }
 
                 log_open();
 
-- 
1.7.7.6


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Re: [systemd-devel] [PATCH-v4 1/2] systemd: mount the securityfs filesystem at early stage

[Lennart Poettering]

On Thu, 15.03.12 19:06, Roberto Sassu (roberto.sassu-8RLafaVCWuNeoWH0uzbU5w@public.gmane.org) wrote:

> The mount of the securityfs filesystem is now performed in the main systemd
> executable as it is used by IMA to provide the interface for loading custom
> policies. The unit file 'units/sys-kernel-security.mount' has been removed
> because it is not longer necessary.

Applied both patches!

Thanks a lot for your work!

Lennart

-- 
Lennart Poettering - Red Hat, Inc.

Re: [PATCH-v4 1/2] systemd: mount the securityfs filesystem at early stage

[Roberto Sassu]

On 03/22/2012 12:25 AM, Lennart Poettering wrote:
> On Thu, 15.03.12 19:06, Roberto Sassu (roberto.sassu@polito.it) wrote:
>
>> The mount of the securityfs filesystem is now performed in the main systemd
>> executable as it is used by IMA to provide the interface for loading custom
>> policies. The unit file 'units/sys-kernel-security.mount' has been removed
>> because it is not longer necessary.
>
> Applied both patches!
>

Hi Lennart

thanks for accepting them!

Regards

Roberto Sassu


> Thanks a lot for your work!
>
> Lennart
>