smack-util.c revision c02e7b1ecc7d88f6529ca3d1d231536300991a02
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Intel Corporation
Author: Auke Kok <auke-jan.h.kok@intel.com>
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 <sys/xattr.h>
#include "util.h"
#include "process-util.h"
#include "path-util.h"
#include "fileio.h"
#include "smack-util.h"
#ifdef HAVE_SMACK
bool mac_smack_use(void) {
static int cached_use = -1;
if (cached_use < 0)
cached_use = access("/sys/fs/smackfs/", F_OK) >= 0;
return cached_use;
}
static const char* const smack_attr_table[_SMACK_ATTR_MAX] = {
[SMACK_ATTR_ACCESS] = "security.SMACK64",
[SMACK_ATTR_EXEC] = "security.SMACK64EXEC",
[SMACK_ATTR_MMAP] = "security.SMACK64MMAP",
[SMACK_ATTR_TRANSMUTE] = "security.SMACK64TRANSMUTE",
[SMACK_ATTR_IPIN] = "security.SMACK64IPIN",
[SMACK_ATTR_IPOUT] = "security.SMACK64IPOUT",
};
DEFINE_STRING_TABLE_LOOKUP(smack_attr, SmackAttr);
int mac_smack_read(const char *path, SmackAttr attr, char **label) {
assert(path);
assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
assert(label);
if (!mac_smack_use())
return 0;
return getxattr_malloc(path, smack_attr_to_string(attr), label, true);
}
int mac_smack_read_fd(int fd, SmackAttr attr, char **label) {
assert(fd >= 0);
assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
assert(label);
if (!mac_smack_use())
return 0;
return fgetxattr_malloc(fd, smack_attr_to_string(attr), label);
}
int mac_smack_apply(const char *path, SmackAttr attr, const char *label) {
int r;
assert(path);
assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
if (!mac_smack_use())
return 0;
if (label)
r = lsetxattr(path, smack_attr_to_string(attr), label, strlen(label), 0);
else
r = lremovexattr(path, smack_attr_to_string(attr));
if (r < 0)
return -errno;
return 0;
}
int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label) {
int r;
assert(fd >= 0);
assert(attr >= 0 && attr < _SMACK_ATTR_MAX);
if (!mac_smack_use())
return 0;
if (label)
r = fsetxattr(fd, smack_attr_to_string(attr), label, strlen(label), 0);
else
r = fremovexattr(fd, smack_attr_to_string(attr));
if (r < 0)
return -errno;
return 0;
}
int mac_smack_apply_pid(pid_t pid, const char *label) {
const char *p;
int r = 0;
assert(label);
if (!mac_smack_use())
return 0;
p = procfs_file_alloca(pid, "attr/current");
r = write_string_file(p, label, 0);
if (r < 0)
return r;
return r;
}
int mac_smack_fix(const char *path, bool ignore_enoent, bool ignore_erofs) {
struct stat st;
int r = 0;
assert(path);
if (!mac_smack_use())
return 0;
/*
* Path must be in /dev and must exist
*/
if (!path_startswith(path, "/dev"))
return 0;
r = lstat(path, &st);
if (r >= 0) {
const char *label;
/*
* Label directories and character devices "*".
* Label symlinks "_".
* Don't change anything else.
*/
if (S_ISDIR(st.st_mode))
label = SMACK_STAR_LABEL;
else if (S_ISLNK(st.st_mode))
label = SMACK_FLOOR_LABEL;
else if (S_ISCHR(st.st_mode))
label = SMACK_STAR_LABEL;
else
return 0;
r = lsetxattr(path, "security.SMACK64", label, strlen(label), 0);
/* If the FS doesn't support labels, then exit without warning */
if (r < 0 && errno == EOPNOTSUPP)
return 0;
}
if (r < 0) {
/* Ignore ENOENT in some cases */
if (ignore_enoent && errno == ENOENT)
return 0;
if (ignore_erofs && errno == EROFS)
return 0;
r = log_debug_errno(errno, "Unable to fix SMACK label of %s: %m", path);
}
return r;
}
int mac_smack_copy(const char *dest, const char *src) {
int r = 0;
_cleanup_free_ char *label = NULL;
assert(dest);
assert(src);
r = mac_smack_read(src, SMACK_ATTR_ACCESS, &label);
if (r < 0)
return r;
r = mac_smack_apply(dest, SMACK_ATTR_ACCESS, label);
if (r < 0)
return r;
return r;
}
#else
bool mac_smack_use(void) {
return false;
}
int mac_smack_read(const char *path, SmackAttr attr, char **label) {
return -EOPNOTSUPP;
}
int mac_smack_read_fd(int fd, SmackAttr attr, char **label) {
return -EOPNOTSUPP;
}
int mac_smack_apply(const char *path, SmackAttr attr, const char *label) {
return 0;
}
int mac_smack_apply_fd(int fd, SmackAttr attr, const char *label) {
return 0;
}
int mac_smack_apply_pid(pid_t pid, const char *label) {
return 0;
}
int mac_smack_fix(const char *path, bool ignore_enoent, bool ignore_erofs) {
return 0;
}
int mac_smack_copy(const char *dest, const char *src) {
return 0;
}
#endif