476 lines
12 KiB
C
476 lines
12 KiB
C
/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <errno.h>
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#include <malloc.h>
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#include <stddef.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/time.h>
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#include <sys/un.h>
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#include <syslog.h>
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#if HAVE_SELINUX
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#include <selinux/context.h>
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#include <selinux/label.h>
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#include <selinux/selinux.h>
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#endif
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#include "alloc-util.h"
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#include "log.h"
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#include "macro.h"
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#include "path-util.h"
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#include "selinux-util.h"
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#include "time-util.h"
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#include "util.h"
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#if HAVE_SELINUX
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DEFINE_TRIVIAL_CLEANUP_FUNC(char*, freecon);
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DEFINE_TRIVIAL_CLEANUP_FUNC(context_t, context_free);
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#define _cleanup_freecon_ _cleanup_(freeconp)
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#define _cleanup_context_free_ _cleanup_(context_freep)
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static int cached_use = -1;
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static struct selabel_handle *label_hnd = NULL;
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#define log_enforcing(...) log_full_errno(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG, errno, __VA_ARGS__)
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#endif
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bool mac_selinux_use(void) {
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#if HAVE_SELINUX
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if (cached_use < 0)
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cached_use = is_selinux_enabled() > 0;
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return cached_use;
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#else
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return false;
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#endif
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}
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void mac_selinux_retest(void) {
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#if HAVE_SELINUX
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cached_use = -1;
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#endif
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}
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int mac_selinux_init(void) {
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int r = 0;
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#if HAVE_SELINUX
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usec_t before_timestamp, after_timestamp;
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struct mallinfo before_mallinfo, after_mallinfo;
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if (label_hnd)
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return 0;
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if (!mac_selinux_use())
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return 0;
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before_mallinfo = mallinfo();
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before_timestamp = now(CLOCK_MONOTONIC);
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label_hnd = selabel_open(SELABEL_CTX_FILE, NULL, 0);
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if (!label_hnd) {
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log_enforcing("Failed to initialize SELinux context: %m");
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r = security_getenforce() == 1 ? -errno : 0;
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} else {
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char timespan[FORMAT_TIMESPAN_MAX];
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int l;
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after_timestamp = now(CLOCK_MONOTONIC);
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after_mallinfo = mallinfo();
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l = after_mallinfo.uordblks > before_mallinfo.uordblks ? after_mallinfo.uordblks - before_mallinfo.uordblks : 0;
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log_debug("Successfully loaded SELinux database in %s, size on heap is %iK.",
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format_timespan(timespan, sizeof(timespan), after_timestamp - before_timestamp, 0),
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(l+1023)/1024);
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}
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#endif
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return r;
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}
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void mac_selinux_finish(void) {
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#if HAVE_SELINUX
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if (!label_hnd)
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return;
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selabel_close(label_hnd);
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label_hnd = NULL;
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#endif
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}
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int mac_selinux_fix(const char *path, bool ignore_enoent, bool ignore_erofs) {
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#if HAVE_SELINUX
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struct stat st;
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int r;
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assert(path);
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/* if mac_selinux_init() wasn't called before we are a NOOP */
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if (!label_hnd)
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return 0;
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r = lstat(path, &st);
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if (r >= 0) {
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_cleanup_freecon_ char* fcon = NULL;
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r = selabel_lookup_raw(label_hnd, &fcon, path, st.st_mode);
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/* If there's no label to set, then exit without warning */
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if (r < 0 && errno == ENOENT)
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return 0;
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if (r >= 0) {
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r = lsetfilecon_raw(path, fcon);
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/* If the FS doesn't support labels, then exit without warning */
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if (r < 0 && errno == EOPNOTSUPP)
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return 0;
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}
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}
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if (r < 0) {
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/* Ignore ENOENT in some cases */
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if (ignore_enoent && errno == ENOENT)
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return 0;
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if (ignore_erofs && errno == EROFS)
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return 0;
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log_enforcing("Unable to fix SELinux security context of %s: %m", path);
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if (security_getenforce() == 1)
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return -errno;
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}
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#endif
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return 0;
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}
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int mac_selinux_apply(const char *path, const char *label) {
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#if HAVE_SELINUX
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if (!mac_selinux_use())
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return 0;
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assert(path);
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assert(label);
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if (setfilecon(path, label) < 0) {
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log_enforcing("Failed to set SELinux security context %s on path %s: %m", label, path);
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if (security_getenforce() > 0)
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return -errno;
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}
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#endif
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return 0;
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}
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int mac_selinux_get_create_label_from_exe(const char *exe, char **label) {
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int r = -EOPNOTSUPP;
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#if HAVE_SELINUX
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_cleanup_freecon_ char *mycon = NULL, *fcon = NULL;
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security_class_t sclass;
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assert(exe);
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assert(label);
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if (!mac_selinux_use())
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return -EOPNOTSUPP;
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r = getcon_raw(&mycon);
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if (r < 0)
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return -errno;
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r = getfilecon_raw(exe, &fcon);
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if (r < 0)
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return -errno;
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sclass = string_to_security_class("process");
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r = security_compute_create_raw(mycon, fcon, sclass, label);
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if (r < 0)
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return -errno;
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#endif
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return r;
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}
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int mac_selinux_get_our_label(char **label) {
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int r = -EOPNOTSUPP;
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assert(label);
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#if HAVE_SELINUX
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if (!mac_selinux_use())
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return -EOPNOTSUPP;
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r = getcon_raw(label);
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if (r < 0)
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return -errno;
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#endif
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return r;
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}
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int mac_selinux_get_child_mls_label(int socket_fd, const char *exe, const char *exec_label, char **label) {
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int r = -EOPNOTSUPP;
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#if HAVE_SELINUX
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_cleanup_freecon_ char *mycon = NULL, *peercon = NULL, *fcon = NULL;
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_cleanup_context_free_ context_t pcon = NULL, bcon = NULL;
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security_class_t sclass;
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const char *range = NULL;
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assert(socket_fd >= 0);
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assert(exe);
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assert(label);
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if (!mac_selinux_use())
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return -EOPNOTSUPP;
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r = getcon_raw(&mycon);
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if (r < 0)
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return -errno;
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r = getpeercon_raw(socket_fd, &peercon);
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if (r < 0)
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return -errno;
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if (!exec_label) {
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/* If there is no context set for next exec let's use context
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of target executable */
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r = getfilecon_raw(exe, &fcon);
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if (r < 0)
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return -errno;
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}
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bcon = context_new(mycon);
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if (!bcon)
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return -ENOMEM;
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pcon = context_new(peercon);
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if (!pcon)
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return -ENOMEM;
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range = context_range_get(pcon);
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if (!range)
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return -errno;
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r = context_range_set(bcon, range);
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if (r)
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return -errno;
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freecon(mycon);
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mycon = strdup(context_str(bcon));
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if (!mycon)
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return -ENOMEM;
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sclass = string_to_security_class("process");
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r = security_compute_create_raw(mycon, fcon, sclass, label);
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if (r < 0)
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return -errno;
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#endif
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return r;
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}
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char* mac_selinux_free(char *label) {
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#if HAVE_SELINUX
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if (!label)
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return NULL;
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if (!mac_selinux_use())
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return NULL;
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freecon(label);
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#endif
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return NULL;
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}
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int mac_selinux_create_file_prepare(const char *path, mode_t mode) {
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#if HAVE_SELINUX
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_cleanup_freecon_ char *filecon = NULL;
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int r;
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assert(path);
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if (!label_hnd)
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return 0;
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if (path_is_absolute(path))
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r = selabel_lookup_raw(label_hnd, &filecon, path, mode);
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else {
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_cleanup_free_ char *newpath = NULL;
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r = path_make_absolute_cwd(path, &newpath);
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if (r < 0)
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return r;
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r = selabel_lookup_raw(label_hnd, &filecon, newpath, mode);
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}
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if (r < 0) {
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/* No context specified by the policy? Proceed without setting it. */
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if (errno == ENOENT)
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return 0;
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log_enforcing("Failed to determine SELinux security context for %s: %m", path);
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} else {
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if (setfscreatecon_raw(filecon) >= 0)
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return 0; /* Success! */
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log_enforcing("Failed to set SELinux security context %s for %s: %m", filecon, path);
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}
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if (security_getenforce() > 0)
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return -errno;
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#endif
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return 0;
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}
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void mac_selinux_create_file_clear(void) {
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#if HAVE_SELINUX
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PROTECT_ERRNO;
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if (!mac_selinux_use())
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return;
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setfscreatecon_raw(NULL);
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#endif
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}
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int mac_selinux_create_socket_prepare(const char *label) {
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#if HAVE_SELINUX
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if (!mac_selinux_use())
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return 0;
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assert(label);
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if (setsockcreatecon(label) < 0) {
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log_enforcing("Failed to set SELinux security context %s for sockets: %m", label);
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if (security_getenforce() == 1)
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return -errno;
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}
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#endif
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return 0;
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}
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void mac_selinux_create_socket_clear(void) {
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#if HAVE_SELINUX
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PROTECT_ERRNO;
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if (!mac_selinux_use())
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return;
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setsockcreatecon_raw(NULL);
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#endif
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}
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int mac_selinux_bind(int fd, const struct sockaddr *addr, socklen_t addrlen) {
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/* Binds a socket and label its file system object according to the SELinux policy */
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#if HAVE_SELINUX
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_cleanup_freecon_ char *fcon = NULL;
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const struct sockaddr_un *un;
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bool context_changed = false;
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char *path;
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int r;
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assert(fd >= 0);
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assert(addr);
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assert(addrlen >= sizeof(sa_family_t));
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if (!label_hnd)
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goto skipped;
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/* Filter out non-local sockets */
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if (addr->sa_family != AF_UNIX)
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goto skipped;
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/* Filter out anonymous sockets */
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if (addrlen < offsetof(struct sockaddr_un, sun_path) + 1)
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goto skipped;
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/* Filter out abstract namespace sockets */
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un = (const struct sockaddr_un*) addr;
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if (un->sun_path[0] == 0)
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goto skipped;
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path = strndupa(un->sun_path, addrlen - offsetof(struct sockaddr_un, sun_path));
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if (path_is_absolute(path))
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r = selabel_lookup_raw(label_hnd, &fcon, path, S_IFSOCK);
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else {
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_cleanup_free_ char *newpath = NULL;
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r = path_make_absolute_cwd(path, &newpath);
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if (r < 0)
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return r;
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r = selabel_lookup_raw(label_hnd, &fcon, newpath, S_IFSOCK);
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}
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if (r < 0) {
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/* No context specified by the policy? Proceed without setting it */
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if (errno == ENOENT)
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goto skipped;
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log_enforcing("Failed to determine SELinux security context for %s: %m", path);
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if (security_getenforce() > 0)
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return -errno;
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} else {
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if (setfscreatecon_raw(fcon) < 0) {
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log_enforcing("Failed to set SELinux security context %s for %s: %m", fcon, path);
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if (security_getenforce() > 0)
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return -errno;
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} else
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context_changed = true;
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}
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r = bind(fd, addr, addrlen) < 0 ? -errno : 0;
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if (context_changed)
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setfscreatecon_raw(NULL);
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return r;
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skipped:
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#endif
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if (bind(fd, addr, addrlen) < 0)
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return -errno;
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return 0;
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}
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