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freebsd/sys/security/lomac/kernel_plm.c
Brian Feldman 3795613d1d Import LOMAC preliminary release 2.0.0 in src/sys/security. These files may
be modified and do not have to remain on the vendor branch.

http://opensource.nailabs.com/lomac/index.html

Sponsored by: DARPA, NAI Labs (CBOSS project)
2001-11-19 22:34:06 +00:00

383 lines
10 KiB
C

/*-
* Copyright (c) 2001 Networks Associates Technologies, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by NAI Labs, the
* Security Research Division of Network Associates, Inc. under
* DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA
* CHATS research program.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id$
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/queue.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/namei.h>
#include "kernel_interface.h"
#include "kernel_plm.h"
#include "lomacfs.h"
#include "policy_plm.h"
MALLOC_DEFINE(M_LOMACPLM, "LOMAC_PLM", "LOMAC PLM nodes and strings");
char *strsep(register char **stringp, register const char *delim);
/*
* Get next token from string *stringp, where tokens are possibly-empty
* strings separated by characters from delim.
*
* Writes NULs into the string at *stringp to end tokens.
* delim need not remain constant from call to call.
* On return, *stringp points past the last NUL written (if there might
* be further tokens), or is NULL (if there are definitely no more tokens).
*
* If *stringp is NULL, strsep returns NULL.
*/
char *
strsep(stringp, delim)
register char **stringp;
register const char *delim;
{
register char *s;
register const char *spanp;
register int c, sc;
char *tok;
if ((s = *stringp) == NULL)
return (NULL);
for (tok = s;;) {
c = *s++;
spanp = delim;
do {
if ((sc = *spanp++) == c) {
if (c == 0)
s = NULL;
else
s[-1] = 0;
*stringp = s;
return (tok);
}
} while (sc != 0);
}
/* NOTREACHED */
}
struct lomac_node_entry lomac_node_entry_root = {
SLIST_HEAD_INITIALIZER(lomac_node_entry),
{ NULL },
LN_HIGHEST_LEVEL | LN_INHERIT_HIGH,
"/"
};
static struct lomac_node_entry *
lomac_plm_subtree_find_cnp(struct lomac_node_entry *root,
struct componentname *cnp) {
char *nameptr = cnp->cn_nameptr;
struct lomac_node_entry *lne;
int len = cnp->cn_namelen;
SLIST_FOREACH(lne, &root->ln_children, ln_chain)
if (strlen(lne->ln_name) == len &&
bcmp(lne->ln_name, nameptr, len) == 0)
break;
return (lne);
}
static struct lomac_node_entry *
lomac_plm_subtree_find(struct lomac_node_entry *root, const char *name) {
struct lomac_node_entry *lne;
SLIST_FOREACH(lne, &root->ln_children, ln_chain)
if (strcmp(name, lne->ln_name) == 0)
break;
return (lne);
}
/*
* This is called from inside getnewvnode() before the vnode is in use.
*/
void
lomac_plm_init_lomacfs_vnode(struct vnode *dvp, struct vnode *vp,
struct componentname *cnp, lattr_t *subjlattr) {
struct lomac_node *ln = VTOLOMAC(vp);
struct lomac_node_entry *mlne = NULL;
/*
* Only "/" has no parent, so inherit directly from our PLM root.
*/
if (dvp == NULL) {
ln->ln_flags = lomac_node_entry_root.ln_flags;
ln->ln_entry = ln->ln_underpolicy = &lomac_node_entry_root;
} else {
struct lomac_node *dln = VTOLOMAC(dvp);
struct lomac_node_entry *dlne = dln->ln_entry;
int fixup_inherit = 0;
/*
* If we have no directory-specific entry, we inherit
* directly from the lomac_node's previously-inherited
* flags implicitly, otherwise we inherit explicitly
* from the corresponding lomac_node_entry.
*/
if (dlne == NULL) {
ln->ln_flags = dln->ln_flags & LN_INHERIT_MASK;
fixup_inherit = 1;
ln->ln_underpolicy = dln->ln_underpolicy;
ln->ln_entry = NULL;
} else if ((mlne = lomac_plm_subtree_find_cnp(dlne, cnp)) ==
NULL) {
ln->ln_flags = dlne->ln_flags & LN_INHERIT_MASK;
fixup_inherit = 2;
ln->ln_underpolicy = dlne;
ln->ln_entry = NULL;
} else {
ln->ln_entry = ln->ln_underpolicy = mlne;
}
if (fixup_inherit) {
switch (ln->ln_flags) {
case LN_INHERIT_LOW:
ln->ln_flags |= LN_LOWEST_LEVEL;
break;
case LN_INHERIT_SUBJ:
if (subjlattr->level == LOMAC_HIGHEST_LEVEL)
ln->ln_flags |= LN_HIGHEST_LEVEL;
else {
ln->ln_flags &= ~LN_INHERIT_MASK;
ln->ln_flags |= LN_INHERIT_LOW |
LN_LOWEST_LEVEL;
}
break;
case LN_INHERIT_HIGH:
ln->ln_flags |= LN_HIGHEST_LEVEL;
break;
}
if (fixup_inherit == 2)
ln->ln_flags |=
(dlne->ln_flags & LN_CHILD_ATTR_MASK) >>
LN_CHILD_ATTR_SHIFT;
} else {
/* this is the only case where mlne != NULL */
ln->ln_flags &= ~(LN_INHERIT_MASK | LN_ATTR_MASK);
ln->ln_flags |= mlne->ln_flags &
(LN_INHERIT_MASK | LN_ATTR_MASK);
if ((mlne->ln_flags & LN_LEVEL_MASK) ==
LN_SUBJ_LEVEL) {
if (subjlattr->level == LOMAC_HIGHEST_LEVEL)
ln->ln_flags |= LN_HIGHEST_LEVEL;
else
ln->ln_flags |= LN_LOWEST_LEVEL;
} else
ln->ln_flags |= mlne->ln_flags & LN_LEVEL_MASK;
}
}
KASSERT(ln->ln_flags & LN_LEVEL_MASK, ("lomac_node has no level"));
KASSERT(ln->ln_flags & LN_INHERIT_MASK, ("lomac_node has no inherit"));
#ifdef INVARIANTS
if (mlne != NULL) {
KASSERT(mlne->ln_flags & LN_LEVEL_MASK,
("lomac_node_entry has no level"));
KASSERT(mlne->ln_flags & LN_INHERIT_MASK,
("lomac_node_entry has no inherit"));
}
#endif /* INVARIANTS */
}
static struct lomac_node_entry *
lomac_plm_subtree_new(struct lomac_node_entry *plne, char *name) {
struct lomac_node_entry *lne;
static struct lomac_node_entry_head head_init =
SLIST_HEAD_INITIALIZER(lomac_node_entry);
lne = malloc(sizeof(*lne), M_LOMACPLM, M_WAITOK);
bcopy(&head_init, &lne->ln_children, sizeof(head_init));
lne->ln_name = name;
lne->ln_flags = plne->ln_flags & LN_INHERIT_MASK;
switch (lne->ln_flags) {
case LN_INHERIT_LOW:
lne->ln_flags |= LN_LOWEST_LEVEL;
break;
case LN_INHERIT_HIGH:
lne->ln_flags |= LN_HIGHEST_LEVEL;
break;
case LN_INHERIT_SUBJ:
lne->ln_flags |= LN_SUBJ_LEVEL;
break;
}
SLIST_INSERT_HEAD(&plne->ln_children, lne, ln_chain);
return (lne);
}
static void
lomac_plm_subtree_free(struct lomac_node_entry *lneself) {
struct lomac_node_entry_head *head = &lneself->ln_children;
struct lomac_node_entry *lne;
while (!SLIST_EMPTY(head)) {
lne = SLIST_FIRST(head);
SLIST_REMOVE_HEAD(head, ln_chain);
lomac_plm_subtree_free(lne);
}
free(lneself, M_LOMACPLM);
}
struct string_list {
SLIST_ENTRY(string_list) entries;
char string[1];
};
static SLIST_HEAD(, string_list) string_list_head =
SLIST_HEAD_INITIALIZER(string_list);
static char *
string_list_new(const char *s) {
struct string_list *sl;
sl = malloc(sizeof(*sl) + strlen(s), M_LOMACPLM, M_WAITOK);
strcpy(sl->string, s);
SLIST_INSERT_HEAD(&string_list_head, sl, entries);
return (sl->string);
}
static void
lomac_plm_uninitialize(void) {
struct lomac_node_entry_head *head = &lomac_node_entry_root.ln_children;
struct lomac_node_entry *lne;
struct string_list *sl;
while (!SLIST_EMPTY(head)) {
lne = SLIST_FIRST(head);
SLIST_REMOVE_HEAD(head, ln_chain);
lomac_plm_subtree_free(lne);
}
while (!SLIST_EMPTY(&string_list_head)) {
sl = SLIST_FIRST(&string_list_head);
SLIST_REMOVE_HEAD(&string_list_head, entries);
free(sl, M_LOMACPLM);
}
}
static int
lomac_plm_initialize(void) {
struct lomac_node_entry *plne, *lne;
plm_rule_t *pr;
for (pr = plm; pr->path != NULL; pr++) {
char *path;
char *comp;
int depth;
if (*pr->path == '\0') {
printf("lomac_plm: invalid path \"%s\"\n", pr->path);
return (EINVAL);
}
path = string_list_new(pr->path);
lne = &lomac_node_entry_root;
depth = 0;
for (;; depth++) {
plne = lne;
comp = strsep(&path, "/");
if (comp == NULL)
break;
if (depth == 0) { /* special case: beginning / */
if (*comp == '\0')
continue;
else {
printf("lomac_plm: not absolute path "
"\"%s\"\n", pr->path);
return (EINVAL);
}
} else if (depth == 1) { /* special case: "/" */
if (*comp == '\0' && strsep(&path, "/") == NULL)
break;
}
if (*comp == '\0' ||
strcmp(comp, ".") == 0 ||
strcmp(comp, "..") == 0) {
printf("lomac_plm: empty path component in "
"\"%s\"\n", pr->path);
return (EINVAL);
}
lne = lomac_plm_subtree_find(plne, comp);
if (lne == NULL) {
lne = lomac_plm_subtree_new(plne, comp);
lne->ln_path = plne->ln_path;
}
}
lne->ln_path = pr->path;
if (pr->flags == PLM_NOFLAGS)
lne->ln_flags &= ~LN_LEVEL_MASK;
else
lne->ln_flags &= ~LN_INHERIT_MASK;
lne->ln_flags |=
plm_levelflags_to_node_flags[pr->level][pr->flags];
if (pr->flags == PLM_NOFLAGS)
lne->ln_flags |= pr->attr;
else
lne->ln_flags |= (pr->attr & LN_ATTR_MASK)
<< LN_CHILD_ATTR_SHIFT;
}
return (0);
}
int lomac_plm_initialized = 0;
static int
lomac_plm_modevent(module_t module, int event, void *unused) {
int error = 0;
switch ((enum modeventtype)event) {
case MOD_LOAD:
error = lomac_plm_initialize();
if (error == 0)
lomac_plm_initialized = 1;
break;
case MOD_UNLOAD:
lomac_plm_uninitialize();
case MOD_SHUTDOWN:
break;
}
return (error);
}
static moduledata_t lomac_plm_moduledata = {
"lomac_plm",
&lomac_plm_modevent,
NULL
};
DECLARE_MODULE(lomac_plm, lomac_plm_moduledata, SI_SUB_VFS, SI_ORDER_ANY);
MODULE_VERSION(lomac_plm, 1);