sys/kern/kern_acl.c

   1 /*-
   2  * Copyright (c) 1999, 2000 Robert N. M. Watson
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  *
  26  * $FreeBSD: src/sys/kern/kern_acl.c,v 1.2.2.1 2000/07/28 18:48:16 rwatson Exp $
  27  * $DragonFly: src/sys/kern/kern_acl.c,v 1.17 2007/02/19 00:51:54 swildner Exp $
  28  */
  29
  30 /*
  31  * Generic routines to support file system ACLs, at a syntactic level
  32  * Semantics are the responsibility of the underlying file system
  33  */
  34
  35 #include <sys/param.h>
  36 #include <sys/systm.h>
  37 #include <sys/sysproto.h>
  38 #include <sys/kernel.h>
  39 #include <sys/malloc.h>
  40 #include <sys/vnode.h>
  41 #include <sys/lock.h>
  42 #include <sys/proc.h>
  43 #include <sys/nlookup.h>
  44 #include <sys/file.h>
  45 #include <sys/sysent.h>
  46 #include <sys/errno.h>
  47 #include <sys/stat.h>
  48 #include <sys/acl.h>
  49
  50 static int vacl_set_acl(struct vnode *vp, acl_type_t type, struct acl *aclp);
  51 static int vacl_get_acl(struct vnode *vp, acl_type_t type, struct acl *aclp);
  52 static int vacl_aclcheck(struct vnode *vp, acl_type_t type, struct acl *aclp);
  53
  54 /*
  55  * These calls wrap the real vnode operations, and are called by the
  56  * syscall code once the syscall has converted the path or file
  57  * descriptor to a vnode (unlocked).  The aclp pointer is assumed
  58  * still to point to userland, so this should not be consumed within
  59  * the kernel except by syscall code.  Other code should directly
  60  * invoke VOP_{SET,GET}ACL.
  61  */
  62
  63 /*
  64  * Given a vnode, set its ACL.
  65  */
  66 static int
  67 vacl_set_acl(struct vnode *vp, acl_type_t type, struct acl *aclp)
  68 {
  69         struct thread *td = curthread;
  70         struct acl inkernacl;
  71         struct ucred *ucred;
  72         int error;
  73
  74         error = copyin(aclp, &inkernacl, sizeof(struct acl));
  75         if (error)
  76                 return(error);
  77         ucred = td->td_ucred;
  78
  79         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
  80         error = VOP_SETACL(vp, type, &inkernacl, ucred);
  81         vn_unlock(vp);
  82         return(error);
  83 }
  84
  85 /*
  86  * Given a vnode, get its ACL.
  87  */
  88 static int
  89 vacl_get_acl(struct vnode *vp, acl_type_t type, struct acl *aclp)
  90 {
  91         struct thread *td = curthread;
  92         struct acl inkernelacl;
  93         struct ucred *ucred;
  94         int error;
  95
  96         ucred = td->td_ucred;
  97         error = VOP_GETACL(vp, type, &inkernelacl, ucred);
  98         if (error == 0)
  99                 error = copyout(&inkernelacl, aclp, sizeof(struct acl));
 100         return (error);
 101 }
 102
 103 /*
 104  * Given a vnode, delete its ACL.
 105  */
 106 static int
 107 vacl_delete(struct vnode *vp, acl_type_t type)
 108 {
 109         struct thread *td = curthread;
 110         struct ucred *ucred;
 111         int error;
 112
 113         ucred = td->td_ucred;
 114         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 115         error = VOP_SETACL(vp, ACL_TYPE_DEFAULT, 0, ucred);
 116         vn_unlock(vp);
 117         return (error);
 118 }
 119
 120 /*
 121  * Given a vnode, check whether an ACL is appropriate for it
 122  */
 123 static int
 124 vacl_aclcheck(struct vnode *vp, acl_type_t type, struct acl *aclp)
 125 {
 126         struct thread *td = curthread;
 127         struct ucred *ucred;
 128         struct acl inkernelacl;
 129         int error;
 130
 131         ucred = td->td_ucred;
 132         error = copyin(aclp, &inkernelacl, sizeof(struct acl));
 133         if (error)
 134                 return(error);
 135         error = VOP_ACLCHECK(vp, type, &inkernelacl, ucred);
 136         return (error);
 137 }
 138
 139 /*
 140  * syscalls -- convert the path/fd to a vnode, and call vacl_whatever.
 141  * Don't need to lock, as the vacl_ code will get/release any locks
 142  * required.
 143  */
 144
 145 /*
 146  * Given a file path, get an ACL for it
 147  */
 148 int
 149 sys___acl_get_file(struct __acl_get_file_args *uap)
 150 {
 151         struct nlookupdata nd;
 152         struct vnode *vp;
 153         int error;
 154
 155         vp = NULL;
 156         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 157         if (error == 0)
 158                 error = nlookup(&nd);
 159         if (error == 0)
 160                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 161         nlookup_done(&nd);
 162         if (error == 0) {
 163                 error = vacl_get_acl(vp, uap->type, uap->aclp);
 164                 vrele(vp);
 165         }
 166         return (error);
 167 }
 168
 169 /*
 170  * Given a file path, set an ACL for it
 171  */
 172 int
 173 sys___acl_set_file(struct __acl_set_file_args *uap)
 174 {
 175         struct nlookupdata nd;
 176         struct vnode *vp;
 177         int error;
 178
 179         vp = NULL;
 180         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 181         if (error == 0)
 182                 error = nlookup(&nd);
 183         if (error == 0)
 184                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 185         nlookup_done(&nd);
 186         if (error == 0) {
 187                 error = vacl_set_acl(vp, uap->type, uap->aclp);
 188                 vrele(vp);
 189         }
 190         return (error);
 191 }
 192
 193 /*
 194  * Given a file descriptor, get an ACL for it
 195  */
 196 int
 197 sys___acl_get_fd(struct __acl_get_fd_args *uap)
 198 {
 199         struct thread *td = curthread;
 200         struct file *fp;
 201         int error;
 202
 203         if ((error = holdvnode(td, uap->filedes, &fp)) != 0)
 204                 return(error);
 205         error = vacl_get_acl((struct vnode *)fp->f_data, uap->type, uap->aclp);
 206         fdrop(fp);
 207
 208         return (error);
 209 }
 210
 211 /*
 212  * Given a file descriptor, set an ACL for it
 213  */
 214 int
 215 sys___acl_set_fd(struct __acl_set_fd_args *uap)
 216 {
 217         struct thread *td = curthread;
 218         struct file *fp;
 219         int error;
 220
 221         if ((error = holdvnode(td, uap->filedes, &fp)) != 0)
 222                 return(error);
 223         error = vacl_set_acl((struct vnode *)fp->f_data, uap->type, uap->aclp);
 224         fdrop(fp);
 225         return (error);
 226 }
 227
 228 /*
 229  * Given a file path, delete an ACL from it.
 230  */
 231 int
 232 sys___acl_delete_file(struct __acl_delete_file_args *uap)
 233 {
 234         struct nlookupdata nd;
 235         struct vnode *vp;
 236         int error;
 237
 238         vp = NULL;
 239         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 240         if (error == 0)
 241                 error = nlookup(&nd);
 242         if (error == 0)
 243                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 244         nlookup_done(&nd);
 245
 246         if (error == 0) {
 247                 error = vacl_delete(vp, uap->type);
 248                 vrele(vp);
 249         }
 250         return (error);
 251 }
 252
 253 /*
 254  * Given a file path, delete an ACL from it.
 255  */
 256 int
 257 sys___acl_delete_fd(struct __acl_delete_fd_args *uap)
 258 {
 259         struct thread *td = curthread;
 260         struct file *fp;
 261         int error;
 262
 263         KKASSERT(td->td_proc);
 264         if ((error = holdvnode(td, uap->filedes, &fp)) != 0)
 265                 return(error);
 266         error = vacl_delete((struct vnode *)fp->f_data, uap->type);
 267         fdrop(fp);
 268         return (error);
 269 }
 270
 271 /*
 272  * Given a file path, check an ACL for it
 273  */
 274 int
 275 sys___acl_aclcheck_file(struct __acl_aclcheck_file_args *uap)
 276 {
 277         struct nlookupdata nd;
 278         struct vnode *vp;
 279         int error;
 280
 281         vp = NULL;
 282         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 283         if (error == 0)
 284                 error = nlookup(&nd);
 285         if (error == 0)
 286                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 287         nlookup_done(&nd);
 288
 289         if (error == 0) {
 290                 error = vacl_aclcheck(vp, uap->type, uap->aclp);
 291                 vrele(vp);
 292         }
 293         return (error);
 294 }
 295
 296 /*
 297  * Given a file descriptor, check an ACL for it
 298  */
 299 int
 300 sys___acl_aclcheck_fd(struct __acl_aclcheck_fd_args *uap)
 301 {
 302         struct thread *td = curthread;
 303         struct file *fp;
 304         int error;
 305
 306         KKASSERT(td->td_proc);
 307         if ((error = holdvnode(td, uap->filedes, &fp)) != 0)
 308                 return(error);
 309         error = vacl_aclcheck((struct vnode *)fp->f_data, uap->type, uap->aclp);
 310         fdrop(fp);
 311         return (error);
 312 }
 313