1 /* 2 * (The copyright below applies to ufs_access()) 3 * 4 * Copyright (c) 1982, 1986, 1989, 1993, 1995 5 * The Regents of the University of California. All rights reserved. 6 * (c) UNIX System Laboratories, Inc. 7 * All or some portions of this file are derived from material licensed 8 * to the University of California by American Telephone and Telegraph 9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 10 * the permission of UNIX System Laboratories, Inc. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)ufs_vnops.c 8.27 (Berkeley) 5/27/95 41 * $DragonFly: src/sys/kern/vfs_helper.c,v 1.5 2008/05/25 18:34:46 dillon Exp $ 42 */ 43 44 #include "opt_quota.h" 45 #include "opt_suiddir.h" 46 47 #include <sys/param.h> 48 #include <sys/systm.h> 49 #include <sys/kernel.h> 50 #include <sys/fcntl.h> 51 #include <sys/stat.h> 52 #include <sys/mount.h> 53 #include <sys/unistd.h> 54 #include <sys/vnode.h> 55 #include <sys/file.h> /* XXX */ 56 #include <sys/proc.h> 57 #include <sys/priv.h> 58 #include <sys/jail.h> 59 60 /* 61 * vop_helper_access() 62 * 63 * Provide standard UNIX semanics for VOP_ACCESS, but without the quota 64 * code. This procedure was basically pulled out of UFS. 65 */ 66 int 67 vop_helper_access(struct vop_access_args *ap, uid_t ino_uid, gid_t ino_gid, 68 mode_t ino_mode, u_int32_t ino_flags) 69 { 70 struct vnode *vp = ap->a_vp; 71 struct ucred *cred = ap->a_cred; 72 mode_t mask, mode = ap->a_mode; 73 gid_t *gp; 74 int i; 75 #ifdef QUOTA 76 /*int error;*/ 77 #endif 78 79 /* 80 * Disallow write attempts on read-only filesystems; 81 * unless the file is a socket, fifo, or a block or 82 * character device resident on the filesystem. 83 */ 84 if (mode & VWRITE) { 85 switch (vp->v_type) { 86 case VDIR: 87 case VLNK: 88 case VREG: 89 case VDATABASE: 90 if (vp->v_mount->mnt_flag & MNT_RDONLY) 91 return (EROFS); 92 #ifdef QUOTA 93 /* check quota here XXX */ 94 #endif 95 break; 96 default: 97 break; 98 } 99 } 100 101 /* If immutable bit set, nobody gets to write it. */ 102 if ((mode & VWRITE) && (ino_flags & IMMUTABLE)) 103 return (EPERM); 104 105 /* Otherwise, user id 0 always gets access. */ 106 if (cred->cr_uid == 0) 107 return (0); 108 109 mask = 0; 110 111 /* Otherwise, check the owner. */ 112 if (cred->cr_uid == ino_uid) { 113 if (mode & VOWN) 114 return (0); 115 if (mode & VEXEC) 116 mask |= S_IXUSR; 117 if (mode & VREAD) 118 mask |= S_IRUSR; 119 if (mode & VWRITE) 120 mask |= S_IWUSR; 121 return ((ino_mode & mask) == mask ? 0 : EACCES); 122 } 123 124 /* Otherwise, check the groups. */ 125 for (i = 0, gp = cred->cr_groups; i < cred->cr_ngroups; i++, gp++) 126 if (ino_gid == *gp) { 127 if (mode & VEXEC) 128 mask |= S_IXGRP; 129 if (mode & VREAD) 130 mask |= S_IRGRP; 131 if (mode & VWRITE) 132 mask |= S_IWGRP; 133 return ((ino_mode & mask) == mask ? 0 : EACCES); 134 } 135 136 /* Otherwise, check everyone else. */ 137 if (mode & VEXEC) 138 mask |= S_IXOTH; 139 if (mode & VREAD) 140 mask |= S_IROTH; 141 if (mode & VWRITE) 142 mask |= S_IWOTH; 143 return ((ino_mode & mask) == mask ? 0 : EACCES); 144 } 145 146 int 147 vop_helper_setattr_flags(u_int32_t *ino_flags, u_int32_t vaflags, 148 uid_t uid, struct ucred *cred) 149 { 150 int error; 151 152 /* 153 * If uid doesn't match only the super-user can change the flags 154 */ 155 if (cred->cr_uid != uid && 156 (error = priv_check_cred(cred, PRIV_ROOT, PRISON_ROOT))) { 157 return(error); 158 } 159 if (cred->cr_uid == 0 && 160 (!jailed(cred)|| jail_chflags_allowed)) { 161 if ((*ino_flags & (SF_NOUNLINK|SF_IMMUTABLE|SF_APPEND)) && 162 securelevel > 0) 163 return (EPERM); 164 *ino_flags = vaflags; 165 } else { 166 if (*ino_flags & (SF_NOUNLINK|SF_IMMUTABLE|SF_APPEND) || 167 (vaflags & UF_SETTABLE) != vaflags) 168 return (EPERM); 169 *ino_flags &= SF_SETTABLE; 170 *ino_flags |= vaflags & UF_SETTABLE; 171 } 172 return(0); 173 } 174 175 /* 176 * This helper function may be used by VFSs to implement UNIX initial 177 * ownership semantics when creating new objects inside directories. 178 */ 179 uid_t 180 vop_helper_create_uid(struct mount *mp, mode_t dmode, uid_t duid, 181 struct ucred *cred, mode_t *modep) 182 { 183 #ifdef SUIDDIR 184 if ((mp->mnt_flag & MNT_SUIDDIR) && (dmode & S_ISUID) && 185 duid != cred->cr_uid && duid) { 186 *modep &= ~07111; 187 return(duid); 188 } 189 #endif 190 return(cred->cr_uid); 191 } 192 193 /* 194 * This helper may be used by VFSs to implement unix chmod semantics. 195 */ 196 int 197 vop_helper_chmod(struct vnode *vp, mode_t new_mode, struct ucred *cred, 198 uid_t cur_uid, gid_t cur_gid, mode_t *cur_modep) 199 { 200 int error; 201 202 if (cred->cr_uid != cur_uid) { 203 error = priv_check_cred(cred, PRIV_ROOT, PRISON_ROOT); 204 if (error) 205 return (error); 206 } 207 if (cred->cr_uid) { 208 if (vp->v_type != VDIR && (*cur_modep & S_ISTXT)) 209 return (EFTYPE); 210 if (!groupmember(cur_gid, cred) && (*cur_modep & S_ISGID)) 211 return (EPERM); 212 } 213 *cur_modep &= ~ALLPERMS; 214 *cur_modep |= new_mode & ALLPERMS; 215 return(0); 216 } 217 218 /* 219 * This helper may be used by VFSs to implement unix chown semantics. 220 */ 221 int 222 vop_helper_chown(struct vnode *vp, uid_t new_uid, gid_t new_gid, 223 struct ucred *cred, 224 uid_t *cur_uidp, gid_t *cur_gidp, mode_t *cur_modep) 225 { 226 gid_t ogid; 227 uid_t ouid; 228 int error; 229 230 if (new_uid == (uid_t)VNOVAL) 231 new_uid = *cur_uidp; 232 if (new_gid == (gid_t)VNOVAL) 233 new_gid = *cur_gidp; 234 235 /* 236 * If we don't own the file, are trying to change the owner 237 * of the file, or are not a member of the target group, 238 * the caller must be superuser or the call fails. 239 */ 240 if ((cred->cr_uid != *cur_uidp || new_uid != *cur_uidp || 241 (new_gid != *cur_gidp && !(cred->cr_gid == new_gid || 242 groupmember(new_gid, cred)))) && 243 (error = priv_check_cred(cred, PRIV_ROOT, PRISON_ROOT))) { 244 return (error); 245 } 246 ogid = *cur_gidp; 247 ouid = *cur_uidp; 248 /* XXX QUOTA CODE */ 249 *cur_uidp = new_uid; 250 *cur_gidp = new_gid; 251 /* XXX QUOTA CODE */ 252 if (cred->cr_uid != 0 && (ouid != new_uid || ogid != new_gid)) 253 *cur_modep &= ~(S_ISUID | S_ISGID); 254 return(0); 255 } 256 257