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 & VEXEC) 114 mask |= S_IXUSR; 115 if (mode & VREAD) 116 mask |= S_IRUSR; 117 if (mode & VWRITE) 118 mask |= S_IWUSR; 119 return ((ino_mode & mask) == mask ? 0 : EACCES); 120 } 121 122 /* Otherwise, check the groups. */ 123 for (i = 0, gp = cred->cr_groups; i < cred->cr_ngroups; i++, gp++) 124 if (ino_gid == *gp) { 125 if (mode & VEXEC) 126 mask |= S_IXGRP; 127 if (mode & VREAD) 128 mask |= S_IRGRP; 129 if (mode & VWRITE) 130 mask |= S_IWGRP; 131 return ((ino_mode & mask) == mask ? 0 : EACCES); 132 } 133 134 /* Otherwise, check everyone else. */ 135 if (mode & VEXEC) 136 mask |= S_IXOTH; 137 if (mode & VREAD) 138 mask |= S_IROTH; 139 if (mode & VWRITE) 140 mask |= S_IWOTH; 141 return ((ino_mode & mask) == mask ? 0 : EACCES); 142 } 143 144 int 145 vop_helper_setattr_flags(u_int32_t *ino_flags, u_int32_t vaflags, 146 uid_t uid, struct ucred *cred) 147 { 148 int error; 149 150 /* 151 * If uid doesn't match only the super-user can change the flags 152 */ 153 if (cred->cr_uid != uid && 154 (error = priv_check_cred(cred, PRIV_ROOT, PRISON_ROOT))) { 155 return(error); 156 } 157 if (cred->cr_uid == 0 && 158 (!jailed(cred)|| jail_chflags_allowed)) { 159 if ((*ino_flags & (SF_NOUNLINK|SF_IMMUTABLE|SF_APPEND)) && 160 securelevel > 0) 161 return (EPERM); 162 *ino_flags = vaflags; 163 } else { 164 if (*ino_flags & (SF_NOUNLINK|SF_IMMUTABLE|SF_APPEND) || 165 (vaflags & UF_SETTABLE) != vaflags) 166 return (EPERM); 167 *ino_flags &= SF_SETTABLE; 168 *ino_flags |= vaflags & UF_SETTABLE; 169 } 170 return(0); 171 } 172 173 /* 174 * This helper function may be used by VFSs to implement UNIX initial 175 * ownership semantics when creating new objects inside directories. 176 */ 177 uid_t 178 vop_helper_create_uid(struct mount *mp, mode_t dmode, uid_t duid, 179 struct ucred *cred, mode_t *modep) 180 { 181 #ifdef SUIDDIR 182 if ((mp->mnt_flag & MNT_SUIDDIR) && (dmode & S_ISUID) && 183 duid != cred->cr_uid && duid) { 184 *modep &= ~07111; 185 return(duid); 186 } 187 #endif 188 return(cred->cr_uid); 189 } 190 191 /* 192 * This helper may be used by VFSs to implement unix chmod semantics. 193 */ 194 int 195 vop_helper_chmod(struct vnode *vp, mode_t new_mode, struct ucred *cred, 196 uid_t cur_uid, gid_t cur_gid, mode_t *cur_modep) 197 { 198 int error; 199 200 if (cred->cr_uid != cur_uid) { 201 error = priv_check_cred(cred, PRIV_ROOT, PRISON_ROOT); 202 if (error) 203 return (error); 204 } 205 if (cred->cr_uid) { 206 if (vp->v_type != VDIR && (*cur_modep & S_ISTXT)) 207 return (EFTYPE); 208 if (!groupmember(cur_gid, cred) && (*cur_modep & S_ISGID)) 209 return (EPERM); 210 } 211 *cur_modep &= ~ALLPERMS; 212 *cur_modep |= new_mode & ALLPERMS; 213 return(0); 214 } 215 216 /* 217 * This helper may be used by VFSs to implement unix chown semantics. 218 */ 219 int 220 vop_helper_chown(struct vnode *vp, uid_t new_uid, gid_t new_gid, 221 struct ucred *cred, 222 uid_t *cur_uidp, gid_t *cur_gidp, mode_t *cur_modep) 223 { 224 gid_t ogid; 225 uid_t ouid; 226 int error; 227 228 if (new_uid == (uid_t)VNOVAL) 229 new_uid = *cur_uidp; 230 if (new_gid == (gid_t)VNOVAL) 231 new_gid = *cur_gidp; 232 233 /* 234 * If we don't own the file, are trying to change the owner 235 * of the file, or are not a member of the target group, 236 * the caller must be superuser or the call fails. 237 */ 238 if ((cred->cr_uid != *cur_uidp || new_uid != *cur_uidp || 239 (new_gid != *cur_gidp && !(cred->cr_gid == new_gid || 240 groupmember(new_gid, cred)))) && 241 (error = priv_check_cred(cred, PRIV_ROOT, PRISON_ROOT))) { 242 return (error); 243 } 244 ogid = *cur_gidp; 245 ouid = *cur_uidp; 246 /* XXX QUOTA CODE */ 247 *cur_uidp = new_uid; 248 *cur_gidp = new_gid; 249 /* XXX QUOTA CODE */ 250 251 /* 252 * DragonFly clears both SUID and SGID if either the owner or 253 * group is changed and root isn't doing it. If root is doing 254 * it we do not clear SUID/SGID. 255 */ 256 if (cred->cr_uid != 0 && (ouid != new_uid || ogid != new_gid)) 257 *cur_modep &= ~(S_ISUID | S_ISGID); 258 return(0); 259 } 260 261