1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
|
/*-
* Copyright (c) 2001 Networks Associates Technology, Inc.
* All rights reserved.
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* 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.
*
* 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.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/signalvar.h>
#include <sys/sx.h>
#include <sys/syscall.h>
#include <sys/sysent.h>
#include <sys/sysproto.h>
#include <sys/systm.h>
#include <sys/linker.h>
#include <sys/mount.h>
#include <sys/mman.h>
#include <sys/dirent.h>
#include <sys/namei.h>
#include <sys/uio.h>
#include <sys/unistd.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_kern.h>
#include "kernel_interface.h"
#include "kernel_util.h"
#include "kernel_mediate.h"
#include "kernel_monitor.h"
#include "lomacfs.h"
#include "syscall_gate/syscall_gate.h"
#define AS(name) (sizeof(struct name) / sizeof(register_t))
int
each_proc(int (*iter)(struct proc *p)) {
struct proc *p;
int error = 0;
sx_slock(&allproc_lock);
LIST_FOREACH(p, &allproc, p_list) {
error = (*iter)(p);
if (error)
goto out;
}
out:
sx_sunlock(&allproc_lock);
return (error);
}
static int
initialize_proc(struct proc *p) {
lattr_t lattr = { LOMAC_HIGHEST_LEVEL, 0 };
init_subject_lattr(p, &lattr);
return (0);
}
static void
lomac_at_fork(struct proc *parent, struct proc *p, int flags) {
if ((flags & RFMEM) == 0) {
lattr_t parent_lattr;
get_subject_lattr(parent, &parent_lattr);
init_subject_lattr(p, &parent_lattr);
}
}
static int
lomac_proc_candebug(struct proc *p1, struct proc *p2) {
lattr_t lattr;
get_subject_lattr(p1, &lattr);
if (mediate_subject_level_subject("debug", p1, lattr.level, p2))
return (0);
else
return (EPERM);
}
static int
lomac_proc_cansched(struct proc *p1, struct proc *p2) {
lattr_t lattr;
get_subject_lattr(p1, &lattr);
if (mediate_subject_level_subject("sched", p1, lattr.level, p2))
return (0);
else
return (EPERM);
}
static int
lomac_proc_cansignal(struct proc *p1, struct proc *p2, int signum) {
lattr_t lattr;
get_subject_lattr(p1, &lattr);
/*
* Always allow signals to init(8) (necessary to shut down).
*/
if (p2->p_pid == 1 ||
mediate_subject_level_subject("signal", p1, lattr.level, p2))
return (0);
else
return (EPERM);
}
int
lomac_initialize_procs(void) {
int error;
#ifdef P_CAN_HOOKS
can_hooks_lock();
(void)p_candebug_hook(lomac_proc_candebug);
(void)p_cansignal_hook(lomac_proc_cansignal);
(void)p_cansched_hook(lomac_proc_cansched);
can_hooks_unlock();
#endif
error = at_fork(lomac_at_fork);
if (error)
return (error);
return (each_proc(&initialize_proc));
}
int
lomac_uninitialize_procs(void) {
rm_at_fork(lomac_at_fork);
return (0);
}
extern int (*old_execve)(struct thread *, struct execve_args *);
int
execve(struct thread *td, struct execve_args *uap) {
lattr_t lattr, textattr;
struct vmspace *oldvmspace;
struct proc *p;
int error;
p = td->td_proc;
get_subject_lattr(p, &lattr);
oldvmspace = p->p_vmspace;
error = old_execve(td, uap);
if (error == 0) {
lomac_object_t lobj;
lobj.lo_type = VISLOMAC(p->p_textvp) ? LO_TYPE_LVNODE :
LO_TYPE_UVNODE;
lobj.lo_object.vnode = p->p_textvp;
get_object_lattr(&lobj, &textattr);
/*
* Install the executable's relevant attributes into the
* process.
*/
lattr.flags |= textattr.flags &
(LOMAC_ATTR_NODEMOTE | LOMAC_ATTR_NONETDEMOTE);
if (p->p_vmspace != oldvmspace)
init_subject_lattr(p, &lattr);
else
set_subject_lattr(p, lattr);
mtx_lock(&Giant);
(void)monitor_read_object(p, &lobj);
mtx_unlock(&Giant);
}
return (error);
}
const char *linker_basename(const char* path);
int linker_load_module(const char *kldname, const char *modname,
struct linker_file *parent, struct mod_depend *verinfo,
struct linker_file **lfpp);
MALLOC_DECLARE(M_LINKER);
/*
* MPSAFE
*/
int
kldload(struct thread* td, struct kldload_args* uap)
{
char *kldname, *modname;
char *pathname = NULL;
linker_file_t lf;
int error = 0;
td->td_retval[0] = -1;
if (securelevel > 0) /* redundant, but that's OK */
return EPERM;
mtx_lock(&Giant);
if ((error = suser_td(td)) != 0)
goto out;
pathname = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
if ((error = copyinstr(SCARG(uap, file), pathname, MAXPATHLEN, NULL)) != 0)
goto out;
if (!mediate_subject_at_level("kldload", td->td_proc,
LOMAC_HIGHEST_LEVEL)) {
error = EPERM;
goto out;
}
/*
* If path do not contain qualified name or any dot in it (kldname.ko, or
* kldname.ver.ko) treat it as interface name.
*/
if (index(pathname, '/') || index(pathname, '.')) {
kldname = pathname;
modname = NULL;
} else {
kldname = NULL;
modname = pathname;
}
error = linker_load_module(kldname, modname, NULL, NULL, &lf);
if (error)
goto out;
lf->userrefs++;
td->td_retval[0] = lf->id;
out:
if (pathname)
free(pathname, M_TEMP);
mtx_unlock(&Giant);
return (error);
}
#ifdef __i386__
#include <machine/sysarch.h>
extern int (*old_sysarch)(struct thread *, void *);
int
sysarch(struct thread *td, struct sysarch_args *uap) {
switch (uap->op) {
case I386_SET_IOPERM:
if (!mediate_subject_at_level("ioperm", td->td_proc,
LOMAC_HIGHEST_LEVEL))
return (EPERM);
default:
return (old_sysarch(td, uap));
}
}
#endif
extern int lomac_mmap(struct proc *, struct mmap_args *);
/*
* Mount a file system.
*/
#ifndef _SYS_SYSPROTO_H_
struct mount_args {
char *type;
char *path;
int flags;
caddr_t data;
};
#endif
/* ARGSUSED */
int
mount(td, uap)
struct thread *td;
struct mount_args /* {
syscallarg(char *) type;
syscallarg(char *) path;
syscallarg(int) flags;
syscallarg(caddr_t) data;
} */ *uap;
{
char *fstype;
char *fspath;
int error;
fstype = malloc(MFSNAMELEN, M_TEMP, M_WAITOK | M_ZERO);
fspath = malloc(MNAMELEN, M_TEMP, M_WAITOK | M_ZERO);
/*
* vfs_mount() actually takes a kernel string for `type' and
* `path' now, so extract them.
*/
error = copyinstr(SCARG(uap, type), fstype, MFSNAMELEN, NULL);
if (error)
goto finish;
error = copyinstr(SCARG(uap, path), fspath, MNAMELEN, NULL);
if (error)
goto finish;
if (!mediate_subject_at_level("mount", td->td_proc,
LOMAC_HIGHEST_LEVEL)) {
error = EPERM;
goto finish;
}
error = vfs_mount(td, fstype, fspath, SCARG(uap, flags),
SCARG(uap, data));
finish:
free(fstype, M_TEMP);
free(fspath, M_TEMP);
return (error);
}
/*
* Unmount a file system.
*
* Note: unmount takes a path to the vnode mounted on as argument,
* not special file (as before).
*/
#ifndef _SYS_SYSPROTO_H_
struct unmount_args {
char *path;
int flags;
};
#endif
/* ARGSUSED */
int
unmount(td, uap)
struct thread *td;
register struct unmount_args /* {
syscallarg(char *) path;
syscallarg(int) flags;
} */ *uap;
{
register struct vnode *vp;
struct mount *mp;
int error;
struct nameidata nd;
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_USERSPACE,
SCARG(uap, path), td);
if ((error = namei(&nd)) != 0)
return (error);
vp = nd.ni_vp;
NDFREE(&nd, NDF_ONLY_PNBUF);
mp = vp->v_mount;
/*
* Only root, or the user that did the original mount is
* permitted to unmount this filesystem.
*/
if (!mediate_subject_at_level("unmount", td->td_proc,
LOMAC_HIGHEST_LEVEL) ||
((mp->mnt_stat.f_owner != td->td_proc->p_ucred->cr_uid) &&
(error = suser_td(td)))) {
vput(vp);
return (error);
}
/*
* Don't allow unmounting the root file system.
*/
if (mp->mnt_flag & MNT_ROOTFS) {
vput(vp);
return (EINVAL);
}
/*
* Must be the root of the filesystem
*/
if ((vp->v_flag & VROOT) == 0) {
vput(vp);
return (EINVAL);
}
vput(vp);
return (dounmount(mp, SCARG(uap, flags), td));
}
static struct syscall_override {
int offset;
sy_call_t *call;
int narg;
int mpsafe;
} syscall_overrides[] = {
{ SYS_mmap, (sy_call_t *)mmap, AS(mmap_args), 1 },
{ SYS_execve, (sy_call_t *)execve, AS(execve_args), 1 },
{ SYS_kldload, (sy_call_t *)kldload, AS(kldload_args), 1 },
{ SYS_mount, (sy_call_t *)mount, AS(mount_args), 0 },
{ SYS_unmount, (sy_call_t *)unmount, AS(unmount_args), 0 },
#ifdef __i386__
{ SYS_sysarch, (sy_call_t *)sysarch, AS(sysarch_args), 1 }
#endif
};
int
lomac_initialize_syscalls(void) {
int error, i;
for (i = 0;
i < sizeof(syscall_overrides) / sizeof(syscall_overrides[0]); i++) {
struct syscall_override *so = &syscall_overrides[i];
error = syscall_gate_register(so->offset, so->call, so->narg,
so->mpsafe);
if (error) {
while (--i >= 0)
syscall_gate_deregister(
syscall_overrides[i].offset);
return (error);
}
}
return (0);
}
int
lomac_uninitialize_syscalls(void) {
int i;
for (i = 0;
i < sizeof(syscall_overrides) / sizeof(syscall_overrides[0]); i++)
syscall_gate_deregister(syscall_overrides[i].offset);
return (0);
}
/* This memory is shared by all lomac_do_recwd() calls, in sequence. */
static char *pathmem;
#define DIRENTMEM_SIZE (64 << 10) /* 64KB is good, I guess! */
static char *direntmem;
static int
lomac_dirents_searchbyid(struct vnode *dvp, struct dirent *dp,
struct dirent *enddp, const struct vattr *vap, struct dirent **retdp)
{
struct vattr pvattr;
struct componentname cnp;
struct thread *td = curthread;
struct ucred *ucred = td->td_ucred;
struct vnode *vp;
int error;
*retdp = NULL;
for (; dp != enddp; dp = (struct dirent *)((char *)dp + dp->d_reclen)) {
cnp.cn_nameiop = LOOKUP;
cnp.cn_flags = LOCKPARENT | ISLASTCN | NOFOLLOW;
cnp.cn_thread = td;
cnp.cn_cred = ucred;
cnp.cn_nameptr = dp->d_name;
cnp.cn_namelen = dp->d_namlen;
error = VOP_LOOKUP(dvp, &vp, &cnp);
if (error)
return (error);
error = VOP_GETATTR(vp, &pvattr, ucred, td);
if (vp != dvp)
(void)vput(vp);
else
vrele(vp); /* if looking up "." */
if (error)
return (error);
if (pvattr.va_fsid == vap->va_fsid &&
pvattr.va_fileid == vap->va_fileid) {
*retdp = dp;
break;
}
}
return (0);
}
static int
lomac_getcwd(
struct thread *td,
char *buf,
size_t buflen,
char **bufret
) {
struct vattr cvattr;
char *bp;
int error, i, slash_prefixed;
struct filedesc *fdp;
struct vnode *vp, *startvp, *dvp;
if (buflen < 2)
return (EINVAL);
if (buflen > MAXPATHLEN)
buflen = MAXPATHLEN;
bp = buf;
bp += buflen - 1;
*bp = '\0';
fdp = td->td_proc->p_fd;
slash_prefixed = 0;
#if defined(LOMAC_DEBUG_RECWD)
printf("lomac_getcwd for %d:\n", td->td_proc->p_pid);
#endif
startvp = fdp->fd_cdir;
vref(startvp);
for (vp = startvp; vp != rootvnode; vp = dvp) {
struct iovec diov = {
direntmem,
DIRENTMEM_SIZE
};
struct uio duio = {
&diov,
1,
0,
DIRENTMEM_SIZE,
UIO_SYSSPACE,
UIO_READ,
curthread
};
struct dirent *dp;
int direof;
if (vp->v_flag & VROOT) {
if (vp->v_mount == NULL) /* forced unmount */
return (EBADF);
dvp = vp->v_mount->mnt_vnodecovered;
continue;
}
dvp = vp->v_dd;
if (vp == dvp)
break;
/*
* Utilize POSIX requirement of files having same
* st_dev and st_ino to be the same file, in our
* case with vattr.va_fsid and vattr.va_fileid.
*/
error = vget(vp, LK_EXCLUSIVE, curthread);
if (error)
goto out2;
error = VOP_GETATTR(vp, &cvattr, curthread->td_ucred,
curthread);
if (error)
goto out2;
(void)vput(vp);
error = vget(dvp, LK_EXCLUSIVE, curthread);
if (error)
goto out2;
for (direof = 0; !direof;) {
error = VOP_READDIR(dvp, &duio,
curthread->td_ucred, &direof, NULL, NULL);
if (error)
break;
error = lomac_dirents_searchbyid(dvp,
(struct dirent *)direntmem,
(struct dirent *)(direntmem +
DIRENTMEM_SIZE - duio.uio_resid),
&cvattr,
&dp);
if (error)
break;
if (dp != NULL) {
(void)vput(dvp);
#if defined(LOMAC_DEBUG_RECWD)
printf("\tdirent component: \"%.*s\"\n",
dp->d_namlen, dp->d_name);
#endif
for (i = dp->d_namlen - 1; i >= 0; i--)
if (bp == buf)
return (ENOMEM);
else
*--bp = dp->d_name[i];
goto nextcomp;
}
diov.iov_base = direntmem;
diov.iov_len = DIRENTMEM_SIZE;
duio.uio_resid = DIRENTMEM_SIZE;
}
if (direof)
error = ENOENT;
(void)vput(dvp);
out2:
#if defined(LOMAC_DEBUG_RECWD)
printf("backup dirent lookup problem: %d\n", error);
#endif
goto out;
nextcomp:
if (bp == buf)
return (ENOMEM);
*--bp = '/';
slash_prefixed = 1;
}
if (!slash_prefixed) {
if (bp == buf)
return (ENOMEM);
*--bp = '/';
}
error = 0;
*bufret = bp;
out:
vrele(startvp);
return (error);
}
static int
lomac_do_recwd(struct proc *p) {
struct nameidata nd;
struct filedesc *fdp = curthread->td_proc->p_fd;
struct thread *td = &p->p_thread;
char *nbuf;
struct vnode *cdir, *rdir, *vp;
int error;
if (p == curthread->td_proc)
return (0);
PROC_LOCK(p);
if (p->p_flag & P_SYSTEM) {
PROC_UNLOCK(p);
return (0);
}
PROC_UNLOCK(p);
error = lomac_getcwd(td, pathmem, MAXPATHLEN, &nbuf);
if (error) {
#if defined(LOMAC_DEBUG_RECWD)
printf("lomac: recwd() failure, lomac_getcwd() == %d\n",
error);
#endif
return (0);
}
rdir = fdp->fd_rdir;
fdp->fd_rdir = rootvnode;
vref(fdp->fd_rdir);
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
nbuf, curthread);
error = namei(&nd);
vrele(fdp->fd_rdir);
fdp->fd_rdir = rdir;
if (error == 0) {
vp = nd.ni_vp;
if (vp->v_type != VDIR)
error = ENOTDIR;
else
error = VOP_ACCESS(vp, VEXEC, td->td_proc->p_ucred,
curthread);
if (error)
vput(vp);
else {
NDFREE(&nd, NDF_ONLY_PNBUF);
fdp = p->p_fd;
cdir = fdp->fd_cdir;
fdp->fd_cdir = vp;
vrele(cdir);
VOP_UNLOCK(vp, 0, curthread);
}
}
#if defined(LOMAC_DEBUG_RECWD)
printf("\trecwd() to \"%.*s\" == %d\n",
MAXPATHLEN, nbuf, error);
#endif
return (0);
}
int
lomac_initialize_cwds(void) {
int error;
pathmem = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
direntmem = malloc(DIRENTMEM_SIZE, M_TEMP, M_WAITOK);
mtx_lock(&Giant);
error = each_proc(lomac_do_recwd);
mtx_unlock(&Giant);
free(pathmem, M_TEMP);
free(direntmem, M_TEMP);
return (error);
}
|