From 816115863962548a9a0d9fbfe429c7f8e685beac Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Thu, 15 Mar 2012 19:06:11 +0100 Subject: [PATCH] main: added support for loading IMA custom policies This is an S/MIME signed message 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 Acked-by: Gianluca Ramunno --- 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 d8155fda..6d0b51a0 100644 --- a/Makefile.am +++ b/Makefile.am @@ -510,6 +510,7 @@ 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 fa17e8be..47a08dda 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 @@ -609,6 +622,7 @@ 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 50cd79dc..06190131 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 00000000..03e43dcf --- /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 . +***/ + +#include +#include +#include +#include +#include +#include +#include +#include + +#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 00000000..7d677cf8 --- /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 . +***/ + +int ima_setup(void); + +#endif diff --git a/src/main.c b/src/main.c index ed317b44..7ae88414 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(); -- 2.39.5