kernel/syscall/gid.c

   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 2008 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 /*
  27  *      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T
  28  */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"
  31
  32 #include <sys/param.h>
  33 #include <sys/types.h>
  34 #include <sys/sysmacros.h>
  35 #include <sys/systm.h>
  36 #include <sys/cred_impl.h>
  37 #include <sys/errno.h>
  38 #include <sys/proc.h>
  39 #include <sys/debug.h>
  40 #include <sys/policy.h>
  41
  42
  43 int
  44 setgid(gid_t gid)
  45 {
  46         proc_t *p;
  47         int error;
  48         int do_nocd = 0;
  49         cred_t  *cr, *newcr;
  50         ksid_t ksid, *ksp;
  51         zone_t  *zone = crgetzone(CRED());
  52
  53
  54         if (!VALID_GID(gid, zone))
  55                 return (set_errno(EINVAL));
  56
  57         if (gid > MAXUID) {
  58                 if (ksid_lookupbygid(zone, gid, &ksid) != 0)
  59                         return (set_errno(EINVAL));
  60                 ksp = &ksid;
  61         } else {
  62                 ksp = NULL;
  63         }
  64
  65         /*
  66          * Need to pre-allocate the new cred structure before grabbing
  67          * the p_crlock mutex.  We cannot hold the mutex across the
  68          * secpolicy functions.
  69          */
  70         newcr = cralloc_ksid();
  71         p = ttoproc(curthread);
  72         mutex_enter(&p->p_crlock);
  73 retry:
  74         cr = p->p_cred;
  75         crhold(cr);
  76         mutex_exit(&p->p_crlock);
  77
  78
  79         if ((gid == cr->cr_rgid || gid == cr->cr_sgid) &&
  80             secpolicy_allow_setid(cr, -1, B_TRUE) != 0) {
  81                 mutex_enter(&p->p_crlock);
  82                 crfree(cr);
  83                 if (cr != p->p_cred)
  84                         goto retry;
  85                 error = 0;
  86                 crcopy_to(cr, newcr);
  87                 p->p_cred = newcr;
  88                 newcr->cr_gid = gid;
  89                 crsetsid(newcr, ksp, KSID_GROUP);
  90                 mutex_exit(&p->p_crlock);
  91         } else if ((error = secpolicy_allow_setid(cr, -1, B_FALSE)) == 0) {
  92                 mutex_enter(&p->p_crlock);
  93                 crfree(cr);
  94                 if (cr != p->p_cred)
  95                         goto retry;
  96                 /*
  97                  * A privileged process that makes itself look like a
  98                  * set-gid process must be marked to produce no core dump.
  99                  */
 100                 if (cr->cr_gid != gid ||
 101                     cr->cr_rgid != gid ||
 102                     cr->cr_sgid != gid)
 103                         do_nocd = 1;
 104                 crcopy_to(cr, newcr);
 105                 p->p_cred = newcr;
 106                 newcr->cr_gid = gid;
 107                 newcr->cr_rgid = gid;
 108                 newcr->cr_sgid = gid;
 109                 crsetsid(newcr, ksp, KSID_GROUP);
 110                 mutex_exit(&p->p_crlock);
 111         } else {
 112                 crfree(newcr);
 113                 crfree(cr);
 114                 if (ksp != NULL)
 115                         ksid_rele(ksp);
 116
 117         }
 118
 119         if (error == 0) {
 120                 if (do_nocd) {
 121                         mutex_enter(&p->p_lock);
 122                         p->p_flag |= SNOCD;
 123                         mutex_exit(&p->p_lock);
 124                 }
 125                 crset(p, newcr);        /* broadcast to process threads */
 126                 return (0);
 127         }
 128         return (set_errno(error));
 129 }
 130
 131 int64_t
 132 getgid(void)
 133 {
 134         rval_t  r;
 135         cred_t  *cr;
 136
 137         cr = curthread->t_cred;
 138         r.r_val1 = cr->cr_rgid;
 139         r.r_val2 = cr->cr_gid;
 140         return (r.r_vals);
 141 }
 142
 143 int
 144 setegid(gid_t gid)
 145 {
 146         proc_t *p;
 147         cred_t  *cr, *newcr;
 148         int error = EPERM;
 149         int do_nocd = 0;
 150         ksid_t ksid, *ksp;
 151         zone_t  *zone = crgetzone(CRED());
 152
 153         if (!VALID_GID(gid, zone))
 154                 return (set_errno(EINVAL));
 155
 156         if (gid > MAXUID) {
 157                 if (ksid_lookupbygid(zone, gid, &ksid) != 0)
 158                         return (set_errno(EINVAL));
 159                 ksp = &ksid;
 160         } else {
 161                 ksp = NULL;
 162         }
 163         /*
 164          * Need to pre-allocate the new cred structure before grabbing
 165          * the p_crlock mutex.
 166          */
 167         newcr = cralloc_ksid();
 168         p = ttoproc(curthread);
 169         mutex_enter(&p->p_crlock);
 170 retry:
 171         crhold(cr = p->p_cred);
 172         mutex_exit(&p->p_crlock);
 173
 174         if (gid == cr->cr_rgid || gid == cr->cr_gid || gid == cr->cr_sgid ||
 175             (error = secpolicy_allow_setid(cr, -1, B_FALSE)) == 0) {
 176                 mutex_enter(&p->p_crlock);
 177                 crfree(cr);
 178                 if (cr != p->p_cred)
 179                         goto retry;
 180                 /*
 181                  * A privileged process that makes itself look like a
 182                  * set-gid process must be marked to produce no core dump.
 183                  */
 184                 if (cr->cr_gid != gid && error == 0)
 185                         do_nocd = 1;
 186                 error = 0;
 187                 crcopy_to(cr, newcr);
 188                 p->p_cred = newcr;
 189                 newcr->cr_gid = gid;
 190                 crsetsid(newcr, ksp, KSID_GROUP);
 191                 mutex_exit(&p->p_crlock);
 192         } else {
 193                 crfree(newcr);
 194                 crfree(cr);
 195                 if (ksp != NULL)
 196                         ksid_rele(ksp);
 197         }
 198
 199         if (error == 0) {
 200                 if (do_nocd) {
 201                         mutex_enter(&p->p_lock);
 202                         p->p_flag |= SNOCD;
 203                         mutex_exit(&p->p_lock);
 204                 }
 205                 crset(p, newcr);        /* broadcast to process threads */
 206                 return (0);
 207         }
 208         return (set_errno(error));
 209 }
 210
 211 /*
 212  * Buy-back from SunOS 4.x
 213  *
 214  * Like setgid() and setegid() combined -except- that non-root users
 215  * can change cr_rgid to cr_gid, and the semantics of cr_sgid are
 216  * subtly different.
 217  */
 218 int
 219 setregid(gid_t rgid, gid_t egid)
 220 {
 221         proc_t *p;
 222         int error = EPERM;
 223         int do_nocd = 0;
 224         cred_t *cr, *newcr;
 225         ksid_t ksid, *ksp;
 226         zone_t  *zone = crgetzone(CRED());
 227
 228         if ((rgid != -1 && !VALID_GID(rgid, zone)) ||
 229             (egid != -1 && !VALID_GID(egid, zone)))
 230                 return (set_errno(EINVAL));
 231
 232         if (egid != -1 && egid > MAXUID) {
 233                 if (ksid_lookupbygid(zone, egid, &ksid) != 0)
 234                         return (set_errno(EINVAL));
 235                 ksp = &ksid;
 236         } else {
 237                 ksp = NULL;
 238         }
 239         /*
 240          * Need to pre-allocate the new cred structure before grabbing
 241          * the p_crlock mutex.
 242          */
 243         newcr = cralloc_ksid();
 244
 245         p = ttoproc(curthread);
 246         mutex_enter(&p->p_crlock);
 247         cr = p->p_cred;
 248
 249         if ((rgid == -1 ||
 250             rgid == cr->cr_rgid || rgid == cr->cr_gid || rgid == cr->cr_sgid) &&
 251             (egid == -1 || egid == cr->cr_rgid || egid == cr->cr_gid ||
 252             egid == cr->cr_sgid) ||
 253             (error = secpolicy_allow_setid(cr, -1, B_FALSE)) == 0) {
 254                 crhold(cr);
 255                 crcopy_to(cr, newcr);
 256                 p->p_cred = newcr;
 257
 258                 if (egid != -1) {
 259                         newcr->cr_gid = egid;
 260                         crsetsid(newcr, ksp, KSID_GROUP);
 261                 }
 262                 if (rgid != -1)
 263                         newcr->cr_rgid = rgid;
 264                 /*
 265                  * "If the real gid is being changed, or the effective gid is
 266                  * being changed to a value not equal to the real gid, the
 267                  * saved gid is set to the new effective gid."
 268                  */
 269                 if (rgid != -1 ||
 270                     (egid != -1 && newcr->cr_gid != newcr->cr_rgid))
 271                         newcr->cr_sgid = newcr->cr_gid;
 272                 /*
 273                  * A privileged process that makes itself look like a
 274                  * set-gid process must be marked to produce no core dump.
 275                  */
 276                 if ((cr->cr_gid != newcr->cr_gid ||
 277                     cr->cr_rgid != newcr->cr_rgid ||
 278                     cr->cr_sgid != newcr->cr_sgid) && error == 0)
 279                         do_nocd = 1;
 280                 error = 0;
 281                 crfree(cr);
 282         }
 283         mutex_exit(&p->p_crlock);
 284
 285         if (error == 0) {
 286                 if (do_nocd) {
 287                         mutex_enter(&p->p_lock);
 288                         p->p_flag |= SNOCD;
 289                         mutex_exit(&p->p_lock);
 290                 }
 291                 crset(p, newcr);        /* broadcast to process threads */
 292                 return (0);
 293         }
 294         crfree(newcr);
 295         if (ksp != NULL)
 296                 ksid_rele(ksp);
 297         return (set_errno(error));
 298 }