1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
23 */
24
25 #include <sys/param.h>
26 #include <sys/types.h>
27 #include <sys/sysmacros.h>
28 #include <sys/systm.h>
29 #include <sys/cred_impl.h>
30 #include <sys/errno.h>
31 #include <sys/klpd.h>
32 #include <sys/proc.h>
33 #include <sys/priv_impl.h>
34 #include <sys/policy.h>
35 #include <sys/ddi.h>
36 #include <sys/thread.h>
37 #include <sys/cmn_err.h>
38 #include <c2/audit.h>
39
40 /*
41 * System call support for manipulating privileges.
42 *
43 *
44 * setppriv(2) - set process privilege set
45 * getppriv(2) - get process privilege set
46 * getprivimplinfo(2) - get process privilege implementation information
47 * setpflags(2) - set process (privilege) flags
48 * getpflags(2) - get process (privilege) flags
49 */
50
51 /*
52 * setppriv (priv_op_t, priv_ptype_t, priv_set_t)
53 */
54 static int
55 setppriv(priv_op_t op, priv_ptype_t type, priv_set_t *in_pset)
56 {
57 priv_set_t pset, *target;
58 cred_t *cr, *pcr;
59 proc_t *p;
60 boolean_t donocd = B_FALSE;
61
62 if (!PRIV_VALIDSET(type) || !PRIV_VALIDOP(op))
63 return (set_errno(EINVAL));
64
65 if (copyin(in_pset, &pset, sizeof (priv_set_t)))
66 return (set_errno(EFAULT));
67
68 p = ttoproc(curthread);
69 cr = cralloc();
70 mutex_enter(&p->p_crlock);
71
72 retry:
73 pcr = p->p_cred;
74
75 if (AU_AUDITING())
76 audit_setppriv(op, type, &pset, pcr);
77
78 /*
79 * Filter out unallowed request (bad op and bad type)
80 */
81 switch (op) {
82 case PRIV_ON:
83 case PRIV_SET:
84 /*
85 * Turning on privileges; the limit set cannot grow,
86 * other sets can but only as long as they remain subsets
87 * of P. Only immediately after exec holds that P <= L.
88 */
89 if (type == PRIV_LIMIT &&
90 !priv_issubset(&pset, &CR_LPRIV(pcr))) {
91 mutex_exit(&p->p_crlock);
92 crfree(cr);
93 return (set_errno(EPERM));
94 }
95 if (!priv_issubset(&pset, &CR_OPPRIV(pcr)) &&
96 !priv_issubset(&pset, priv_getset(pcr, type))) {
97 mutex_exit(&p->p_crlock);
98 /* Policy override should not grow beyond L either */
99 if (type != PRIV_INHERITABLE ||
100 !priv_issubset(&pset, &CR_LPRIV(pcr)) ||
101 secpolicy_require_privs(CRED(), &pset) != 0) {
102 crfree(cr);
103 return (set_errno(EPERM));
104 }
105 mutex_enter(&p->p_crlock);
106 if (pcr != p->p_cred)
107 goto retry;
108 donocd = B_TRUE;
109 }
110 break;
111
112 case PRIV_OFF:
113 /* PRIV_OFF is always allowed */
114 break;
115 }
116
117 /*
118 * OK! everything is cool.
119 * Do cred COW.
120 */
121 crcopy_to(pcr, cr);
122
123 /*
124 * If we change the effective, permitted or limit set, we attain
125 * "privilege awareness".
126 */
127 if (type != PRIV_INHERITABLE)
128 priv_set_PA(cr);
129
130 target = &(CR_PRIVS(cr)->crprivs[type]);
131
132 switch (op) {
133 case PRIV_ON:
134 priv_union(&pset, target);
135 break;
136 case PRIV_OFF:
137 priv_inverse(&pset);
138 priv_intersect(target, &pset);
139
140 /*
141 * Fall-thru to set target and change other process
142 * privilege sets.
143 */
144 /*FALLTHRU*/
145
146 case PRIV_SET:
147 *target = pset;
148
149 /*
150 * Take privileges no longer permitted out
151 * of other effective sets as well.
152 * Limit set is enforced at exec() time.
153 */
154 if (type == PRIV_PERMITTED)
155 priv_intersect(&pset, &CR_EPRIV(cr));
156 break;
157 }
158
159 /*
160 * When we give up privileges not in the inheritable set,
161 * set SNOCD if not already set; first we compute the
162 * privileges removed from P using Diff = (~P') & P
163 * and then we check whether the removed privileges are
164 * a subset of I. If we retain uid 0, all privileges
165 * are required anyway so don't set SNOCD.
166 */
167 if (type == PRIV_PERMITTED && (p->p_flag & SNOCD) == 0 &&
168 cr->cr_uid != 0 && cr->cr_ruid != 0 && cr->cr_suid != 0) {
169 priv_set_t diff = CR_OPPRIV(cr);
170 priv_inverse(&diff);
171 priv_intersect(&CR_OPPRIV(pcr), &diff);
172 donocd = !priv_issubset(&diff, &CR_IPRIV(cr));
173 }
174
175 p->p_cred = cr;
176 mutex_exit(&p->p_crlock);
177
178 if (donocd) {
179 mutex_enter(&p->p_lock);
180 p->p_flag |= SNOCD;
181 mutex_exit(&p->p_lock);
182 }
183
184 /*
185 * The basic_test privilege should not be removed from E;
186 * if that has happened, then some programmer typically set the E/P to
187 * empty. That is not portable.
188 */
189 if ((type == PRIV_EFFECTIVE || type == PRIV_PERMITTED) &&
190 priv_basic_test >= 0 && !PRIV_ISASSERT(target, priv_basic_test)) {
191 proc_t *p = curproc;
192 pid_t pid = p->p_pid;
193 char *fn = PTOU(p)->u_comm;
194
195 cmn_err(CE_WARN, "%s[%d]: setppriv: basic_test privilege "
196 "removed from E/P", fn, pid);
197 }
198
199 crset(p, cr); /* broadcast to process threads */
200
201 return (0);
202 }
203
204 /*
205 * getppriv (priv_ptype_t, priv_set_t *)
206 */
207 static int
208 getppriv(priv_ptype_t type, priv_set_t *pset)
209 {
210 if (!PRIV_VALIDSET(type))
211 return (set_errno(EINVAL));
212
213 if (copyout(priv_getset(CRED(), type), pset, sizeof (priv_set_t)) != 0)
214 return (set_errno(EFAULT));
215
216 return (0);
217 }
218
219 static int
220 getprivimplinfo(void *buf, size_t bufsize)
221 {
222 int err;
223
224 err = copyout(priv_hold_implinfo(), buf, min(bufsize, privinfosize));
225
226 priv_release_implinfo();
227
228 if (err)
229 return (set_errno(EFAULT));
230
231 return (0);
232 }
233
234 /*
235 * Set process flags in the given target cred. If NULL is specified, then
236 * CRED() is used; otherwise the cred is assumed to be modifiable (i.e. newly
237 * crdup'ed, or equivalent). Some flags are set in the proc rather than cred;
238 * for these, curproc is always used.
239 *
240 * For now we cheat: the flags are actually bit masks so we can simplify
241 * some; we do make sure that the arguments are valid, though.
242 */
243
244 int
245 setpflags(uint_t flag, uint_t val, cred_t *tcr)
246 {
247 cred_t *cr, *pcr;
248 proc_t *p = curproc;
249 uint_t newflags;
250 boolean_t use_curcred = (tcr == NULL);
251
252 if (val > 1 || (flag != PRIV_DEBUG && flag != PRIV_AWARE &&
253 flag != NET_MAC_AWARE && flag != NET_MAC_AWARE_INHERIT &&
254 flag != __PROC_PROTECT && flag != PRIV_XPOLICY &&
255 flag != PRIV_AWARE_RESET && flag != PRIV_PFEXEC)) {
256 return (EINVAL);
257 }
258
259 if (flag == __PROC_PROTECT) {
260 mutex_enter(&p->p_lock);
261 if (val == 0)
262 p->p_flag &= ~SNOCD;
263 else
264 p->p_flag |= SNOCD;
265 mutex_exit(&p->p_lock);
266 return (0);
267 }
268
269 if (use_curcred) {
270 cr = cralloc();
271 mutex_enter(&p->p_crlock);
272 pcr = p->p_cred;
273 } else {
274 cr = pcr = tcr;
275 }
276
277 newflags = CR_FLAGS(pcr);
278
279 if (val != 0) {
280 if (flag == PRIV_AWARE)
281 newflags &= ~PRIV_AWARE_RESET;
282 newflags |= flag;
283 } else {
284 newflags &= ~flag;
285 }
286
287 /* No change */
288 if (CR_FLAGS(pcr) == newflags) {
289 if (use_curcred) {
290 mutex_exit(&p->p_crlock);
291 crfree(cr);
292 }
293 return (0);
294 }
295
296 /*
297 * Setting either the NET_MAC_AWARE or NET_MAC_AWARE_INHERIT
298 * flags is a restricted operation.
299 *
300 * When invoked via the PRIVSYS_SETPFLAGS syscall
301 * we require that the current cred has the net_mac_aware
302 * privilege in its effective set.
303 *
304 * When called from within the kernel by label-aware
305 * services such as NFS, we don't require a privilege check.
306 *
307 */
308 if ((flag == NET_MAC_AWARE || flag == NET_MAC_AWARE_INHERIT) &&
309 (val == 1) && use_curcred) {
310 if (secpolicy_net_mac_aware(pcr) != 0) {
311 mutex_exit(&p->p_crlock);
312 crfree(cr);
313 return (EPERM);
314 }
315 }
316
317 /* Trying to unset PA; if we can't, return an error */
318 if (flag == PRIV_AWARE && val == 0 && !priv_can_clear_PA(pcr)) {
319 if (use_curcred) {
320 mutex_exit(&p->p_crlock);
321 crfree(cr);
322 }
323 return (EPERM);
324 }
325
326 /* Committed to changing the flag */
327 if (use_curcred)
328 crcopy_to(pcr, cr);
329 if (flag == PRIV_AWARE) {
330 if (val != 0)
331 priv_set_PA(cr);
332 else
333 priv_adjust_PA(cr);
334 } else {
335 CR_FLAGS(cr) = newflags;
336 }
337
338 /*
339 * Unsetting the flag has as side effect getting rid of
340 * the per-credential policy.
341 */
342 if (flag == PRIV_XPOLICY && val == 0)
343 crsetcrklpd(cr, NULL);
344
345 if (use_curcred) {
346 p->p_cred = cr;
347 mutex_exit(&p->p_crlock);
348 crset(p, cr);
349 }
350
351 return (0);
352 }
353
354 /*
355 * Getpflags. Currently only implements single bit flags.
356 */
357 uint_t
358 getpflags(uint_t flag, const cred_t *cr)
359 {
360 if (flag != PRIV_DEBUG && flag != PRIV_AWARE &&
361 flag != NET_MAC_AWARE && flag != NET_MAC_AWARE_INHERIT &&
362 flag != PRIV_XPOLICY && flag != PRIV_PFEXEC &&
363 flag != PRIV_AWARE_RESET)
364 return ((uint_t)-1);
365
366 return ((CR_FLAGS(cr) & flag) != 0);
367 }
368
369 /*
370 * Privilege system call entry point
371 */
372 int
373 privsys(int code, priv_op_t op, priv_ptype_t type, void *buf, size_t bufsize,
374 int itype)
375 {
376 int retv;
377 extern int issetugid(void);
378
379 switch (code) {
380 case PRIVSYS_SETPPRIV:
381 if (bufsize < sizeof (priv_set_t))
382 return (set_errno(ENOMEM));
383 return (setppriv(op, type, buf));
384 case PRIVSYS_GETPPRIV:
385 if (bufsize < sizeof (priv_set_t))
386 return (set_errno(ENOMEM));
387 return (getppriv(type, buf));
388 case PRIVSYS_GETIMPLINFO:
389 return (getprivimplinfo(buf, bufsize));
390 case PRIVSYS_SETPFLAGS:
391 retv = setpflags((uint_t)op, (uint_t)type, NULL);
392 return (retv != 0 ? set_errno(retv) : 0);
393 case PRIVSYS_GETPFLAGS:
394 retv = (int)getpflags((uint_t)op, CRED());
395 return (retv == -1 ? set_errno(EINVAL) : retv);
396 case PRIVSYS_ISSETUGID:
397 return (issetugid());
398 case PRIVSYS_KLPD_REG:
399 if (bufsize < sizeof (priv_set_t))
400 return (set_errno(ENOMEM));
401 return ((int)klpd_reg((int)op, (idtype_t)itype, (id_t)type,
402 buf));
403 case PRIVSYS_KLPD_UNREG:
404 return ((int)klpd_unreg((int)op, (idtype_t)itype, (id_t)type));
405 case PRIVSYS_PFEXEC_REG:
406 return ((int)pfexec_reg((int)op));
407 case PRIVSYS_PFEXEC_UNREG:
408 return ((int)pfexec_unreg((int)op));
409 }
410 return (set_errno(EINVAL));
411 }
412
413 #ifdef _SYSCALL32_IMPL
414 int
415 privsys32(int code, priv_op_t op, priv_ptype_t type, caddr32_t buf,
416 size32_t bufsize, int itype)
417 {
418 return (privsys(code, op, type, (void *)(uintptr_t)buf,
419 (size_t)bufsize, itype));
420 }
421 #endif