main: added support for loading IMA custom policies

[elogind.git] / src / ima-setup.c

diff --git a/src/ima-setup.c b/src/ima-setup.c
new file mode 100644 (file)
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;
+}