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 2007 Sun Microsystems, Inc. All rights reserved. 23 * Use is subject to license terms. 24 */ 25 26 /* Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T */ 27 /* All Rights Reserved */ 28 29 /* 30 * Portions of this source code were derived from Berkeley 4.3 BSD 31 * under license from the Regents of the University of California. 32 */ 33 34 #pragma ident "%Z%%M% %I% %E% SMI" 35 36 #include <sys/param.h> 37 #include <sys/isa_defs.h> 38 #include <sys/types.h> 39 #include <sys/sysmacros.h> 40 #include <sys/cred.h> 41 #include <sys/user.h> 42 #include <sys/systm.h> 43 #include <sys/errno.h> 44 #include <sys/fcntl.h> 45 #include <sys/pathname.h> 46 #include <sys/var.h> 47 #include <sys/vfs.h> 48 #include <sys/vnode.h> 49 #include <sys/file.h> 50 #include <sys/mode.h> 51 #include <sys/proc.h> 52 #include <sys/uio.h> 53 #include <sys/poll.h> 54 #include <sys/kmem.h> 55 #include <sys/filio.h> 56 #include <sys/cmn_err.h> 57 #include <sys/policy.h> 58 #include <sys/zone.h> 59 60 #include <sys/debug.h> 61 #include <c2/audit.h> 62 #include <fs/fs_subr.h> 63 64 /* 65 * Change current working directory ("."). 66 */ 67 static int chdirec(vnode_t *, int ischroot, int do_traverse); 68 69 int 70 chdir(char *fname) 71 { 72 vnode_t *vp; 73 int error; 74 int estale_retry = 0; 75 76 lookup: 77 if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) { 78 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 79 goto lookup; 80 return (set_errno(error)); 81 } 82 83 error = chdirec(vp, 0, 1); 84 if (error) { 85 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 86 goto lookup; 87 return (set_errno(error)); 88 } 89 return (0); 90 } 91 92 /* 93 * File-descriptor based version of 'chdir'. 94 */ 95 int 96 fchdir(int fd) 97 { 98 vnode_t *vp; 99 file_t *fp; 100 int error; 101 102 if ((fp = getf(fd)) == NULL) 103 return (set_errno(EBADF)); 104 vp = fp->f_vnode; 105 VN_HOLD(vp); 106 releasef(fd); 107 error = chdirec(vp, 0, 0); 108 if (error) 109 return (set_errno(error)); 110 return (0); 111 } 112 113 /* 114 * Change notion of root ("/") directory. 115 */ 116 int 117 chroot(char *fname) 118 { 119 vnode_t *vp; 120 int error; 121 int estale_retry = 0; 122 123 lookup: 124 if (error = lookupname(fname, UIO_USERSPACE, FOLLOW, NULLVPP, &vp)) { 125 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 126 goto lookup; 127 return (set_errno(error)); 128 } 129 130 error = chdirec(vp, 1, 1); 131 if (error) { 132 if ((error == ESTALE) && fs_need_estale_retry(estale_retry++)) 133 goto lookup; 134 return (set_errno(error)); 135 } 136 return (0); 137 } 138 139 /* 140 * ++++++++++++++++++++++++ 141 * ++ SunOS4.1 Buyback ++ 142 * ++++++++++++++++++++++++ 143 * Change root directory with a user given fd 144 */ 145 int 146 fchroot(int fd) 147 { 148 vnode_t *vp; 149 file_t *fp; 150 int error; 151 152 if ((fp = getf(fd)) == NULL) 153 return (set_errno(EBADF)); 154 vp = fp->f_vnode; 155 VN_HOLD(vp); 156 releasef(fd); 157 error = chdirec(vp, 1, 0); 158 if (error) 159 return (set_errno(error)); 160 return (0); 161 } 162 163 static int 164 chdirec(vnode_t *vp, int ischroot, int do_traverse) 165 { 166 int error; 167 vnode_t *oldvp; 168 proc_t *pp = curproc; 169 vnode_t **vpp; 170 refstr_t *cwd; 171 int newcwd = 1; 172 173 if (vp->v_type != VDIR) { 174 error = ENOTDIR; 175 goto bad; 176 } 177 if (error = VOP_ACCESS(vp, VEXEC, 0, CRED(), NULL)) 178 goto bad; 179 180 /* 181 * The VOP_ACCESS() may have covered 'vp' with a new filesystem, 182 * if 'vp' is an autoFS vnode. Traverse the mountpoint so 183 * that we don't end up with a covered current directory. 184 */ 185 if (vn_mountedvfs(vp) != NULL && do_traverse) { 186 if (error = traverse(&vp)) 187 goto bad; 188 } 189 190 /* 191 * Special chroot semantics: chroot is allowed if privileged 192 * or if the target is really a loopback mount of the root (or 193 * root of the zone) as determined by comparing dev and inode 194 * numbers 195 */ 196 if (ischroot) { 197 struct vattr tattr; 198 struct vattr rattr; 199 vnode_t *zonevp = curproc->p_zone->zone_rootvp; 200 201 tattr.va_mask = AT_FSID|AT_NODEID; 202 if (error = VOP_GETATTR(vp, &tattr, 0, CRED(), NULL)) 203 goto bad; 204 205 rattr.va_mask = AT_FSID|AT_NODEID; 206 if (error = VOP_GETATTR(zonevp, &rattr, 0, CRED(), NULL)) 207 goto bad; 208 209 if ((tattr.va_fsid != rattr.va_fsid || 210 tattr.va_nodeid != rattr.va_nodeid) && 211 (error = secpolicy_chroot(CRED())) != 0) 212 goto bad; 213 214 vpp = &PTOU(pp)->u_rdir; 215 } else { 216 vpp = &PTOU(pp)->u_cdir; 217 } 218 219 if (audit_active) /* update abs cwd/root path see c2audit.c */ 220 audit_chdirec(vp, vpp); 221 222 mutex_enter(&pp->p_lock); 223 /* 224 * This bit of logic prevents us from overwriting u_cwd if we are 225 * changing to the same directory. We set the cwd to NULL so that we 226 * don't try to do the lookup on the next call to getcwd(). 227 */ 228 if (!ischroot && *vpp != NULL && vp != NULL && VN_CMP(*vpp, vp)) 229 newcwd = 0; 230 231 oldvp = *vpp; 232 *vpp = vp; 233 if ((cwd = PTOU(pp)->u_cwd) != NULL && newcwd) 234 PTOU(pp)->u_cwd = NULL; 235 mutex_exit(&pp->p_lock); 236 237 if (cwd && newcwd) 238 refstr_rele(cwd); 239 if (oldvp) 240 VN_RELE(oldvp); 241 return (0); 242 243 bad: 244 VN_RELE(vp); 245 return (error); 246 } 247