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/conf.h> 50 #include <sys/kernel.h> 51 #include <sys/fcntl.h> 52 #include <sys/stat.h> 53 #include <sys/mount.h> 54 #include <sys/unistd.h> 55 #include <sys/vnode.h> 56 #include <sys/file.h> /* XXX */ 57 #include <sys/proc.h> 58 #include <sys/priv.h> 59 #include <sys/jail.h> 60 61 /* 62 * vop_helper_access() 63 * 64 * Provide standard UNIX semanics for VOP_ACCESS, but without the quota 65 * code. This procedure was basically pulled out of UFS. 66 */ 67 int 68 vop_helper_access(struct vop_access_args *ap, uid_t ino_uid, gid_t ino_gid, 69 mode_t ino_mode, u_int32_t ino_flags) 70 { 71 struct vnode *vp = ap->a_vp; 72 struct ucred *cred = ap->a_cred; 73 mode_t mask, mode = ap->a_mode; 74 gid_t *gp; 75 int i; 76 uid_t proc_uid; 77 gid_t proc_gid; 78 79 if (ap->a_flags & AT_EACCESS) { 80 proc_uid = cred->cr_uid; 81 proc_gid = cred->cr_gid; 82 } else { 83 proc_uid = cred->cr_ruid; 84 proc_gid = cred->cr_rgid; 85 } 86 87 /* 88 * Disallow write attempts on read-only filesystems; 89 * unless the file is a socket, fifo, or a block or 90 * character device resident on the filesystem. 91 */ 92 if (mode & VWRITE) { 93 switch (vp->v_type) { 94 case VDIR: 95 case VLNK: 96 case VREG: 97 case VDATABASE: 98 if (vp->v_mount->mnt_flag & MNT_RDONLY) 99 return (EROFS); 100 break; 101 default: 102 break; 103 } 104 } 105 106 /* If immutable bit set, nobody gets to write it. */ 107 if ((mode & VWRITE) && (ino_flags & IMMUTABLE)) 108 return (EPERM); 109 110 /* Otherwise, user id 0 always gets access. */ 111 if (proc_uid == 0) 112 return (0); 113 114 mask = 0; 115 116 /* Otherwise, check the owner. */ 117 if (proc_uid == ino_uid) { 118 if (mode & VEXEC) 119 mask |= S_IXUSR; 120 if (mode & VREAD) 121 mask |= S_IRUSR; 122 if (mode & VWRITE) 123 mask |= S_IWUSR; 124 return ((ino_mode & mask) == mask ? 0 : EACCES); 125 } 126 127 /* 128 * Otherwise, check the groups. 129 * We must special-case the primary group to, if needed, check against 130 * the real gid and not the effective one. 131 */ 132 if (proc_gid == ino_gid) { 133 if (mode & VEXEC) 134 mask |= S_IXGRP; 135 if (mode & VREAD) 136 mask |= S_IRGRP; 137 if (mode & VWRITE) 138 mask |= S_IWGRP; 139 return ((ino_mode & mask) == mask ? 0 : EACCES); 140 } 141 for (i = 1, gp = &cred->cr_groups[1]; i < cred->cr_ngroups; i++, gp++) 142 if (ino_gid == *gp) { 143 if (mode & VEXEC) 144 mask |= S_IXGRP; 145 if (mode & VREAD) 146 mask |= S_IRGRP; 147 if (mode & VWRITE) 148 mask |= S_IWGRP; 149 return ((ino_mode & mask) == mask ? 0 : EACCES); 150 } 151 152 /* Otherwise, check everyone else. */ 153 if (mode & VEXEC) 154 mask |= S_IXOTH; 155 if (mode & VREAD) 156 mask |= S_IROTH; 157 if (mode & VWRITE) 158 mask |= S_IWOTH; 159 return ((ino_mode & mask) == mask ? 0 : EACCES); 160 } 161 162 int 163 vop_helper_setattr_flags(u_int32_t *ino_flags, u_int32_t vaflags, 164 uid_t uid, struct ucred *cred) 165 { 166 int error; 167 168 /* 169 * If uid doesn't match only a privileged user can change the flags 170 */ 171 if (cred->cr_uid != uid && 172 (error = priv_check_cred(cred, PRIV_VFS_SYSFLAGS, 0))) { 173 return(error); 174 } 175 if (cred->cr_uid == 0 && 176 (!jailed(cred)|| jail_chflags_allowed)) { 177 if ((*ino_flags & (SF_NOUNLINK|SF_IMMUTABLE|SF_APPEND)) && 178 securelevel > 0) 179 return (EPERM); 180 *ino_flags = vaflags; 181 } else { 182 if (*ino_flags & (SF_NOUNLINK|SF_IMMUTABLE|SF_APPEND) || 183 (vaflags & UF_SETTABLE) != vaflags) 184 return (EPERM); 185 *ino_flags &= SF_SETTABLE; 186 *ino_flags |= vaflags & UF_SETTABLE; 187 } 188 return(0); 189 } 190 191 /* 192 * This helper function may be used by VFSs to implement UNIX initial 193 * ownership semantics when creating new objects inside directories. 194 */ 195 uid_t 196 vop_helper_create_uid(struct mount *mp, mode_t dmode, uid_t duid, 197 struct ucred *cred, mode_t *modep) 198 { 199 #ifdef SUIDDIR 200 if ((mp->mnt_flag & MNT_SUIDDIR) && (dmode & S_ISUID) && 201 duid != cred->cr_uid && duid) { 202 *modep &= ~07111; 203 return(duid); 204 } 205 #endif 206 return(cred->cr_uid); 207 } 208 209 /* 210 * This helper may be used by VFSs to implement unix chmod semantics. 211 */ 212 int 213 vop_helper_chmod(struct vnode *vp, mode_t new_mode, struct ucred *cred, 214 uid_t cur_uid, gid_t cur_gid, mode_t *cur_modep) 215 { 216 int error; 217 218 if (cred->cr_uid != cur_uid) { 219 error = priv_check_cred(cred, PRIV_VFS_CHMOD, 0); 220 if (error) 221 return (error); 222 } 223 if (cred->cr_uid) { 224 if (vp->v_type != VDIR && (*cur_modep & S_ISTXT)) 225 return (EFTYPE); 226 if (!groupmember(cur_gid, cred) && (*cur_modep & S_ISGID)) 227 return (EPERM); 228 } 229 *cur_modep &= ~ALLPERMS; 230 *cur_modep |= new_mode & ALLPERMS; 231 return(0); 232 } 233 234 /* 235 * This helper may be used by VFSs to implement unix chown semantics. 236 */ 237 int 238 vop_helper_chown(struct vnode *vp, uid_t new_uid, gid_t new_gid, 239 struct ucred *cred, 240 uid_t *cur_uidp, gid_t *cur_gidp, mode_t *cur_modep) 241 { 242 gid_t ogid; 243 uid_t ouid; 244 int error; 245 246 if (new_uid == (uid_t)VNOVAL) 247 new_uid = *cur_uidp; 248 if (new_gid == (gid_t)VNOVAL) 249 new_gid = *cur_gidp; 250 251 /* 252 * If we don't own the file, are trying to change the owner 253 * of the file, or are not a member of the target group, 254 * the caller must be privileged or the call fails. 255 */ 256 if ((cred->cr_uid != *cur_uidp || new_uid != *cur_uidp || 257 (new_gid != *cur_gidp && !(cred->cr_gid == new_gid || 258 groupmember(new_gid, cred)))) && 259 (error = priv_check_cred(cred, PRIV_VFS_CHOWN, 0))) { 260 return (error); 261 } 262 ogid = *cur_gidp; 263 ouid = *cur_uidp; 264 /* XXX QUOTA CODE */ 265 *cur_uidp = new_uid; 266 *cur_gidp = new_gid; 267 /* XXX QUOTA CODE */ 268 269 /* 270 * DragonFly clears both SUID and SGID if either the owner or 271 * group is changed and root isn't doing it. If root is doing 272 * it we do not clear SUID/SGID. 273 */ 274 if (cred->cr_uid != 0 && (ouid != new_uid || ogid != new_gid)) 275 *cur_modep &= ~(S_ISUID | S_ISGID); 276 return(0); 277 } 278 279