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/sysmsg.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 sysmsg *sysmsg,
 150                    const struct __acl_get_file_args *uap)
 151 {
 152         struct nlookupdata nd;
 153         struct vnode *vp;
 154         int error;
 155
 156         vp = NULL;
 157         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 158         if (error == 0)
 159                 error = nlookup(&nd);
 160         if (error == 0)
 161                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 162         nlookup_done(&nd);
 163         if (error == 0) {
 164                 error = vacl_get_acl(vp, uap->type, uap->aclp);
 165                 vrele(vp);
 166         }
 167         return (error);
 168 }
 169
 170 /*
 171  * Given a file path, set an ACL for it
 172  */
 173 int
 174 sys___acl_set_file(struct sysmsg *sysmsg,
 175                    const struct __acl_set_file_args *uap)
 176 {
 177         struct nlookupdata nd;
 178         struct vnode *vp;
 179         int error;
 180
 181         vp = NULL;
 182         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 183         if (error == 0)
 184                 error = nlookup(&nd);
 185         if (error == 0)
 186                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 187         nlookup_done(&nd);
 188         if (error == 0) {
 189                 error = vacl_set_acl(vp, uap->type, uap->aclp);
 190                 vrele(vp);
 191         }
 192         return (error);
 193 }
 194
 195 /*
 196  * Given a file descriptor, get an ACL for it
 197  */
 198 int
 199 sys___acl_get_fd(struct sysmsg *sysmsg,
 200                  const struct __acl_get_fd_args *uap)
 201 {
 202         struct thread *td = curthread;
 203         struct file *fp;
 204         int error;
 205
 206         if ((error = holdvnode(td, uap->filedes, &fp)) != 0)
 207                 return(error);
 208         error = vacl_get_acl((struct vnode *)fp->f_data, uap->type, uap->aclp);
 209         fdrop(fp);
 210
 211         return (error);
 212 }
 213
 214 /*
 215  * Given a file descriptor, set an ACL for it
 216  */
 217 int
 218 sys___acl_set_fd(struct sysmsg *sysmsg,
 219                  const struct __acl_set_fd_args *uap)
 220 {
 221         struct thread *td = curthread;
 222         struct file *fp;
 223         int error;
 224
 225         if ((error = holdvnode(td, uap->filedes, &fp)) != 0)
 226                 return(error);
 227         error = vacl_set_acl((struct vnode *)fp->f_data, uap->type, uap->aclp);
 228         fdrop(fp);
 229         return (error);
 230 }
 231
 232 /*
 233  * Given a file path, delete an ACL from it.
 234  */
 235 int
 236 sys___acl_delete_file(struct sysmsg *sysmsg,
 237                       const struct __acl_delete_file_args *uap)
 238 {
 239         struct nlookupdata nd;
 240         struct vnode *vp;
 241         int error;
 242
 243         vp = NULL;
 244         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 245         if (error == 0)
 246                 error = nlookup(&nd);
 247         if (error == 0)
 248                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 249         nlookup_done(&nd);
 250
 251         if (error == 0) {
 252                 error = vacl_delete(vp, uap->type);
 253                 vrele(vp);
 254         }
 255         return (error);
 256 }
 257
 258 /*
 259  * Given a file path, delete an ACL from it.
 260  */
 261 int
 262 sys___acl_delete_fd(struct sysmsg *sysmsg,
 263                     const struct __acl_delete_fd_args *uap)
 264 {
 265         struct thread *td = curthread;
 266         struct file *fp;
 267         int error;
 268
 269         KKASSERT(td->td_proc);
 270         if ((error = holdvnode(td, uap->filedes, &fp)) != 0)
 271                 return(error);
 272         error = vacl_delete((struct vnode *)fp->f_data, uap->type);
 273         fdrop(fp);
 274         return (error);
 275 }
 276
 277 /*
 278  * Given a file path, check an ACL for it
 279  */
 280 int
 281 sys___acl_aclcheck_file(struct sysmsg *sysmsg,
 282                         const struct __acl_aclcheck_file_args *uap)
 283 {
 284         struct nlookupdata nd;
 285         struct vnode *vp;
 286         int error;
 287
 288         vp = NULL;
 289         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 290         if (error == 0)
 291                 error = nlookup(&nd);
 292         if (error == 0)
 293                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 294         nlookup_done(&nd);
 295
 296         if (error == 0) {
 297                 error = vacl_aclcheck(vp, uap->type, uap->aclp);
 298                 vrele(vp);
 299         }
 300         return (error);
 301 }
 302
 303 /*
 304  * Given a file descriptor, check an ACL for it
 305  */
 306 int
 307 sys___acl_aclcheck_fd(struct sysmsg *sysmsg,
 308                       const struct __acl_aclcheck_fd_args *uap)
 309 {
 310         struct thread *td = curthread;
 311         struct file *fp;
 312         int error;
 313
 314         KKASSERT(td->td_proc);
 315         if ((error = holdvnode(td, uap->filedes, &fp)) != 0)
 316                 return(error);
 317         error = vacl_aclcheck((struct vnode *)fp->f_data, uap->type, uap->aclp);
 318         fdrop(fp);
 319         return (error);
 320 }
 321