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security: rework selinux, smack, ima, apparmor detection logic

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Always cache the results, and bypass low-level security calls when the
respective subsystem is not enabled.
This commit is contained in:
Lennart Poettering 2013-10-10 16:35:44 +02:00
parent 0581dac2c1
commit d682b3a7e7
14 changed files with 197 additions and 52 deletions
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6
Makefile.am
View file

@ -725,7 +725,11 @@ libsystemd_shared_la_SOURCES = \
src/shared/mkdir.c \
src/shared/mkdir.h \
src/shared/smack-util.c \
src/shared/smack-util.h
src/shared/smack-util.h \
src/shared/apparmor-util.c \
src/shared/apparmor-util.h \
src/shared/ima-util.c \
src/shared/ima-util.h
#-------------------------------------------------------------------------------
noinst_LTLIBRARIES += \

29
src/core/condition.c
View file

@ -27,10 +27,6 @@
#include <sys/statvfs.h>
#include <fnmatch.h>
#ifdef HAVE_SELINUX
#include <selinux/selinux.h>
#endif
#include <systemd/sd-id128.h>
#include "util.h"
#include "condition.h"
@ -38,6 +34,10 @@
#include "path-util.h"
#include "fileio.h"
#include "unit.h"
#include "smack-util.h"
#include "apparmor-util.h"
#include "ima-util.h"
#include "selinux-util.h"
Condition* condition_new(ConditionType type, const char *parameter, bool trigger, bool negate) {
Condition *c;
@ -158,28 +158,15 @@ static bool test_virtualization(const char *parameter) {
return v > 0 && streq(parameter, id);
}
static bool test_apparmor_enabled(void) {
int r;
_cleanup_free_ char *p = NULL;
r = read_one_line_file("/sys/module/apparmor/parameters/enabled", &p);
if (r < 0)
return false;
return parse_boolean(p) > 0;
}
static bool test_security(const char *parameter) {
#ifdef HAVE_SELINUX
if (streq(parameter, "selinux"))
return is_selinux_enabled() > 0;
#endif
return use_selinux();
if (streq(parameter, "apparmor"))
return test_apparmor_enabled();
return use_apparmor();
if (streq(parameter, "ima"))
return access("/sys/kernel/security/ima/", F_OK) == 0;
return use_ima();
if (streq(parameter, "smack"))
return access("/sys/fs/smackfs", F_OK) == 0;
return use_smack();
return false;
}

6
src/core/socket.c
View file

@ -775,12 +775,12 @@ static void socket_apply_socket_options(Socket *s, int fd) {
}
#ifdef HAVE_SMACK
if (s->smack_ip_in)
if (s->smack_ip_in && use_smack())
if (fsetxattr(fd, "security.SMACK64IPIN", s->smack_ip_in, strlen(s->smack_ip_in), 0) < 0)
log_error_unit(UNIT(s)->id,
"fsetxattr(\"security.SMACK64IPIN\"): %m");
if (s->smack_ip_out)
if (s->smack_ip_out && use_smack())
if (fsetxattr(fd, "security.SMACK64IPOUT", s->smack_ip_out, strlen(s->smack_ip_out), 0) < 0)
log_error_unit(UNIT(s)->id,
"fsetxattr(\"security.SMACK64IPOUT\"): %m");
@ -797,7 +797,7 @@ static void socket_apply_fifo_options(Socket *s, int fd) {
"F_SETPIPE_SZ: %m");
#ifdef HAVE_SMACK
if (s->smack)
if (s->smack && use_smack())
if (fsetxattr(fd, "security.SMACK64", s->smack, strlen(s->smack), 0) < 0)
log_error_unit(UNIT(s)->id,
"fsetxattr(\"security.SMACK64\"): %m");

11
src/journal/journald-native.c
View file

@ -25,6 +25,7 @@
#include "socket-util.h"
#include "path-util.h"
#include "selinux-util.h"
#include "journald-server.h"
#include "journald-native.h"
#include "journald-kmsg.h"
@ -404,10 +405,12 @@ int server_open_native_socket(Server*s) {
}
#ifdef HAVE_SELINUX
one = 1;
r = setsockopt(s->native_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
if (r < 0)
log_warning("SO_PASSSEC failed: %m");
if (use_selinux()) {
one = 1;
r = setsockopt(s->native_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
if (r < 0)
log_warning("SO_PASSSEC failed: %m");
}
#endif
one = 1;

24
src/journal/journald-server.c
View file

@ -629,19 +629,21 @@ static void dispatch_message_real(
}
#ifdef HAVE_SELINUX
if (label) {
x = alloca(sizeof("_SELINUX_CONTEXT=") + label_len);
if (use_selinux()) {
if (label) {
x = alloca(sizeof("_SELINUX_CONTEXT=") + label_len);
*((char*) mempcpy(stpcpy(x, "_SELINUX_CONTEXT="), label, label_len)) = 0;
IOVEC_SET_STRING(iovec[n++], x);
} else {
security_context_t con;
if (getpidcon(ucred->pid, &con) >= 0) {
x = strappenda("_SELINUX_CONTEXT=", con);
freecon(con);
*((char*) mempcpy(stpcpy(x, "_SELINUX_CONTEXT="), label, label_len)) = 0;
IOVEC_SET_STRING(iovec[n++], x);
} else {
security_context_t con;
if (getpidcon(ucred->pid, &con) >= 0) {
x = strappenda("_SELINUX_CONTEXT=", con);
freecon(con);
IOVEC_SET_STRING(iovec[n++], x);
}
}
}
#endif

7
src/journal/journald-stream.c
View file

@ -29,6 +29,7 @@
#endif
#include "socket-util.h"
#include "selinux-util.h"
#include "journald-server.h"
#include "journald-stream.h"
#include "journald-syslog.h"
@ -381,8 +382,10 @@ int stdout_stream_new(Server *s) {
}
#ifdef HAVE_SELINUX
if (getpeercon(fd, &stream->security_context) < 0 && errno != ENOPROTOOPT)
log_error("Failed to determine peer security context: %m");
if (use_selinux()) {
if (getpeercon(fd, &stream->security_context) < 0 && errno != ENOPROTOOPT)
log_error("Failed to determine peer security context: %m");
}
#endif
if (shutdown(fd, SHUT_WR) < 0) {

11
src/journal/journald-syslog.c
View file

@ -25,6 +25,7 @@
#include "systemd/sd-messages.h"
#include "socket-util.h"
#include "selinux-util.h"
#include "journald-server.h"
#include "journald-syslog.h"
#include "journald-kmsg.h"
@ -453,10 +454,12 @@ int server_open_syslog_socket(Server *s) {
}
#ifdef HAVE_SELINUX
one = 1;
r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
if (r < 0)
log_warning("SO_PASSSEC failed: %m");
if (use_selinux()) {
one = 1;
r = setsockopt(s->syslog_fd, SOL_SOCKET, SO_PASSSEC, &one, sizeof(one));
if (r < 0)
log_warning("SO_PASSSEC failed: %m");
}
#endif
one = 1;

41
src/shared/apparmor-util.c Normal file
View file

@ -0,0 +1,41 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd 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.
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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <unistd.h>
#include "util.h"
#include "fileio.h"
#include "apparmor-util.h"
static int use_apparmor_cached = -1;
bool use_apparmor(void) {
if (use_apparmor_cached < 0) {
_cleanup_free_ char *p = NULL;
use_apparmor_cached =
read_one_line_file("/sys/module/apparmor/parameters/enabled", &p) >= 0 &&
parse_boolean(p) > 0;
}
return use_apparmor_cached;
}

26
src/shared/apparmor-util.h Normal file
View file

@ -0,0 +1,26 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#pragma once
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd 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.
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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdbool.h>
bool use_apparmor(void);

35
src/shared/ima-util.c Normal file
View file

@ -0,0 +1,35 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd 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.
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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <unistd.h>
#include "apparmor-util.h"
static int use_ima_cached = -1;
bool use_ima(void) {
if (use_ima_cached < 0)
use_ima_cached = access("/sys/kernel/security/ima/", F_OK) >= 0;
return use_ima_cached;
}

26
src/shared/ima-util.h Normal file
View file

@ -0,0 +1,26 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#pragma once
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd 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.
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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdbool.h>
bool use_ima(void);

9
src/shared/selinux-util.c
View file

@ -39,4 +39,13 @@ void retest_selinux(void) {
use_selinux_cached = -1;
}
#else
bool use_selinux(void) {
return false;
}
void retest_selinux(void) {
}
#endif

13
src/shared/smack-util.c
View file

@ -21,16 +21,21 @@
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include "smack-util.h"
#include <unistd.h>
static int use_smack_cached = -1;
#include "smack-util.h"
bool use_smack(void) {
#ifdef HAVE_SMACK
static int use_smack_cached = -1;
if (use_smack_cached < 0)
use_smack_cached = (access("/sys/fs/smackfs", F_OK) >= 0);
use_smack_cached = access("/sys/fs/smackfs/", F_OK) >= 0;
return use_smack_cached;
#else
return false;
#endif
}

5
src/udev/udev-node.c
View file

@ -32,6 +32,7 @@
#include <attr/xattr.h>
#endif
#include "smack-util.h"
#include "udev.h"
static int node_symlink(struct udev_device *dev, const char *node, const char *slink)
@ -311,7 +312,7 @@ static int node_permissions_apply(struct udev_device *dev, bool apply,
log_debug("SECLABEL: set SELinux label '%s'", label);
#ifdef HAVE_SMACK
} else if (streq(name, "smack")) {
} else if (streq(name, "smack") && use_smack()) {
smack = true;
if (lsetxattr(devnode, "security.SMACK64", label, strlen(label), 0) < 0)
log_error("SECLABEL: failed to set SMACK label '%s'", label);
@ -327,7 +328,7 @@ static int node_permissions_apply(struct udev_device *dev, bool apply,
if (!selinux)
label_fix(devnode, true, false);
#ifdef HAVE_SMACK
if (!smack)
if (!smack && use_smack())
lremovexattr(devnode, "security.SMACK64");
#endif
}