sys/kern/vfs_helper.c

   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 1.1 2007/11/02 19:54:14 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
  57 /*
  58  * vop_helper_access()
  59  *
  60  *      Provide standard UNIX semanics for VOP_ACCESS, but without the quota
  61  *      code.  This procedure was basically pulled out of UFS.
  62  */
  63 int
  64 vop_helper_access(struct vop_access_args *ap, uid_t ino_uid, gid_t ino_gid,
  65                   mode_t ino_mode, u_int32_t ino_flags)
  66 {
  67         struct vnode *vp = ap->a_vp;
  68         struct ucred *cred = ap->a_cred;
  69         mode_t mask, mode = ap->a_mode;
  70         gid_t *gp;
  71         int i;
  72 #ifdef QUOTA
  73         /*int error;*/
  74 #endif
  75
  76         /*
  77          * Disallow write attempts on read-only filesystems;
  78          * unless the file is a socket, fifo, or a block or
  79          * character device resident on the filesystem.
  80          */
  81         if (mode & VWRITE) {
  82                 switch (vp->v_type) {
  83                 case VDIR:
  84                 case VLNK:
  85                 case VREG:
  86                 case VDATABASE:
  87                         if (vp->v_mount->mnt_flag & MNT_RDONLY)
  88                                 return (EROFS);
  89 #ifdef QUOTA
  90                         /* check quota here XXX */
  91 #endif
  92                         break;
  93                 default:
  94                         break;
  95                 }
  96         }
  97
  98         /* If immutable bit set, nobody gets to write it. */
  99         if ((mode & VWRITE) && (ino_flags & IMMUTABLE))
 100                 return (EPERM);
 101
 102         /* Otherwise, user id 0 always gets access. */
 103         if (cred->cr_uid == 0)
 104                 return (0);
 105
 106         mask = 0;
 107
 108         /* Otherwise, check the owner. */
 109         if (cred->cr_uid == ino_uid) {
 110                 if (mode & VEXEC)
 111                         mask |= S_IXUSR;
 112                 if (mode & VREAD)
 113                         mask |= S_IRUSR;
 114                 if (mode & VWRITE)
 115                         mask |= S_IWUSR;
 116                 return ((ino_mode & mask) == mask ? 0 : EACCES);
 117         }
 118
 119         /* Otherwise, check the groups. */
 120         for (i = 0, gp = cred->cr_groups; i < cred->cr_ngroups; i++, gp++)
 121                 if (ino_gid == *gp) {
 122                         if (mode & VEXEC)
 123                                 mask |= S_IXGRP;
 124                         if (mode & VREAD)
 125                                 mask |= S_IRGRP;
 126                         if (mode & VWRITE)
 127                                 mask |= S_IWGRP;
 128                         return ((ino_mode & mask) == mask ? 0 : EACCES);
 129                 }
 130
 131         /* Otherwise, check everyone else. */
 132         if (mode & VEXEC)
 133                 mask |= S_IXOTH;
 134         if (mode & VREAD)
 135                 mask |= S_IROTH;
 136         if (mode & VWRITE)
 137                 mask |= S_IWOTH;
 138         return ((ino_mode & mask) == mask ? 0 : EACCES);
 139 }
 140