290 lines
7.4 KiB
C
290 lines
7.4 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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/***
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Copyright © 2013 Intel Corporation
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Author: Auke Kok <auke-jan.h.kok@intel.com>
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***/
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#include <errno.h>
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#include <fcntl.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/xattr.h>
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#include <unistd.h>
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#include "alloc-util.h"
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#include "fd-util.h"
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#include "fileio.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 "process-util.h"
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#include "smack-util.h"
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#include "stdio-util.h"
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#include "string-table.h"
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#include "xattr-util.h"
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#if ENABLE_SMACK
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bool mac_smack_use(void) {
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static int cached_use = -1;
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if (cached_use < 0)
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cached_use = access("/sys/fs/smackfs/", F_OK) >= 0;
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return cached_use;
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}
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static const char* const smack_attr_table[_SMACK_ATTR_MAX] = {
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[SMACK_ATTR_ACCESS] = "security.SMACK64",
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[SMACK_ATTR_EXEC] = "security.SMACK64EXEC",
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[SMACK_ATTR_MMAP] = "security.SMACK64MMAP",
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[SMACK_ATTR_TRANSMUTE] = "security.SMACK64TRANSMUTE",
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[SMACK_ATTR_IPIN] = "security.SMACK64IPIN",
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[SMACK_ATTR_IPOUT] = "security.SMACK64IPOUT",
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};
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DEFINE_STRING_TABLE_LOOKUP(smack_attr, SmackAttr);
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int mac_smack_read(const char *path, SmackAttr attr, char **label) {
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assert(path);
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assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
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assert(label);
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if (!mac_smack_use())
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return 0;
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return getxattr_malloc(path, smack_attr_to_string(attr), label, true);
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}
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int mac_smack_read_fd(int fd, SmackAttr attr, char **label) {
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assert(fd >= 0);
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assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
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assert(label);
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if (!mac_smack_use())
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return 0;
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return fgetxattr_malloc(fd, smack_attr_to_string(attr), label);
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}
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int mac_smack_apply(const char *path, SmackAttr attr, const char *label) {
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int r;
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assert(path);
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assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
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if (!mac_smack_use())
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return 0;
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if (label)
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r = lsetxattr(path, smack_attr_to_string(attr), label, strlen(label), 0);
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else
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r = lremovexattr(path, smack_attr_to_string(attr));
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if (r < 0)
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return -errno;
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return 0;
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}
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int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label) {
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int r;
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assert(fd >= 0);
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assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
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if (!mac_smack_use())
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return 0;
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if (label)
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r = fsetxattr(fd, smack_attr_to_string(attr), label, strlen(label), 0);
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else
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r = fremovexattr(fd, smack_attr_to_string(attr));
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if (r < 0)
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return -errno;
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return 0;
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}
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int mac_smack_apply_pid(pid_t pid, const char *label) {
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const char *p;
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int r = 0;
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assert(label);
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if (!mac_smack_use())
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return 0;
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p = procfs_file_alloca(pid, "attr/current");
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r = write_string_file(p, label, WRITE_STRING_FILE_DISABLE_BUFFER);
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if (r < 0)
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return r;
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return r;
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}
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static int smack_fix_fd(int fd , const char *abspath, LabelFixFlags flags) {
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char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int)];
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const char *label;
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struct stat st;
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int r;
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/* The caller should have done the sanity checks. */
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assert(abspath);
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assert(path_is_absolute(abspath));
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/* Path must be in /dev. */
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if (!path_startswith(abspath, "/dev"))
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return 0;
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if (fstat(fd, &st) < 0)
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return -errno;
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/*
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* Label directories and character devices "*".
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* Label symlinks "_".
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* Don't change anything else.
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*/
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if (S_ISDIR(st.st_mode))
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label = SMACK_STAR_LABEL;
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else if (S_ISLNK(st.st_mode))
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label = SMACK_FLOOR_LABEL;
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else if (S_ISCHR(st.st_mode))
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label = SMACK_STAR_LABEL;
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else
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return 0;
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xsprintf(procfs_path, "/proc/self/fd/%i", fd);
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if (setxattr(procfs_path, "security.SMACK64", label, strlen(label), 0) < 0) {
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_cleanup_free_ char *old_label = NULL;
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r = -errno;
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/* If the FS doesn't support labels, then exit without warning */
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if (r == -EOPNOTSUPP)
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return 0;
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/* It the FS is read-only and we were told to ignore failures caused by that, suppress error */
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if (r == -EROFS && (flags & LABEL_IGNORE_EROFS))
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return 0;
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/* If the old label is identical to the new one, suppress any kind of error */
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if (getxattr_malloc(procfs_path, "security.SMACK64", &old_label, false) >= 0 &&
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streq(old_label, label))
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return 0;
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return log_debug_errno(r, "Unable to fix SMACK label of %s: %m", abspath);
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}
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return 0;
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}
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int mac_smack_fix_at(int dirfd, const char *path, LabelFixFlags flags) {
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_cleanup_free_ char *p = NULL;
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_cleanup_close_ int fd = -1;
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int r;
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assert(path);
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if (!mac_smack_use())
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return 0;
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fd = openat(dirfd, path, O_NOFOLLOW|O_CLOEXEC|O_PATH);
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if (fd < 0) {
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if ((flags & LABEL_IGNORE_ENOENT) && errno == ENOENT)
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return 0;
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return -errno;
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}
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if (!path_is_absolute(path)) {
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r = fd_get_path(fd, &p);
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if (r < 0)
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return r;
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path = p;
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}
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return smack_fix_fd(fd, path, flags);
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}
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int mac_smack_fix(const char *path, LabelFixFlags flags) {
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_cleanup_free_ char *abspath = NULL;
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_cleanup_close_ int fd = -1;
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int r;
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assert(path);
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if (!mac_smack_use())
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return 0;
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r = path_make_absolute_cwd(path, &abspath);
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if (r < 0)
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return r;
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fd = open(abspath, O_NOFOLLOW|O_CLOEXEC|O_PATH);
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if (fd < 0) {
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if ((flags & LABEL_IGNORE_ENOENT) && errno == ENOENT)
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return 0;
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return -errno;
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}
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return smack_fix_fd(fd, abspath, flags);
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}
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int mac_smack_copy(const char *dest, const char *src) {
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int r = 0;
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_cleanup_free_ char *label = NULL;
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assert(dest);
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assert(src);
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r = mac_smack_read(src, SMACK_ATTR_ACCESS, &label);
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if (r < 0)
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return r;
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r = mac_smack_apply(dest, SMACK_ATTR_ACCESS, label);
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if (r < 0)
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return r;
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return r;
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}
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#else
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bool mac_smack_use(void) {
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return false;
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}
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int mac_smack_read(const char *path, SmackAttr attr, char **label) {
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return -EOPNOTSUPP;
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}
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int mac_smack_read_fd(int fd, SmackAttr attr, char **label) {
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return -EOPNOTSUPP;
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}
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int mac_smack_apply(const char *path, SmackAttr attr, const char *label) {
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return 0;
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}
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int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label) {
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return 0;
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}
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int mac_smack_apply_pid(pid_t pid, const char *label) {
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return 0;
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}
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int mac_smack_fix(const char *path, LabelFixFlags flags) {
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return 0;
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}
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int mac_smack_fix_at(int dirfd, const char *path, LabelFixFlags flags) {
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return 0;
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}
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int mac_smack_copy(const char *dest, const char *src) {
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return 0;
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}
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#endif
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