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 #include <sys/mplock2.h>
  51
  52 static int vacl_set_acl(struct vnode *vp, acl_type_t type, struct acl *aclp);
  53 static int vacl_get_acl(struct vnode *vp, acl_type_t type, struct acl *aclp);
  54 static int vacl_aclcheck(struct vnode *vp, acl_type_t type, struct acl *aclp);
  55
  56 /*
  57  * These calls wrap the real vnode operations, and are called by the
  58  * syscall code once the syscall has converted the path or file
  59  * descriptor to a vnode (unlocked).  The aclp pointer is assumed
  60  * still to point to userland, so this should not be consumed within
  61  * the kernel except by syscall code.  Other code should directly
  62  * invoke VOP_{SET,GET}ACL.
  63  */
  64
  65 /*
  66  * Given a vnode, set its ACL.
  67  */
  68 static int
  69 vacl_set_acl(struct vnode *vp, acl_type_t type, struct acl *aclp)
  70 {
  71         struct thread *td = curthread;
  72         struct acl inkernacl;
  73         struct ucred *ucred;
  74         int error;
  75
  76         error = copyin(aclp, &inkernacl, sizeof(struct acl));
  77         if (error)
  78                 return(error);
  79         ucred = td->td_ucred;
  80
  81         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
  82         error = VOP_SETACL(vp, type, &inkernacl, ucred);
  83         vn_unlock(vp);
  84         return(error);
  85 }
  86
  87 /*
  88  * Given a vnode, get its ACL.
  89  */
  90 static int
  91 vacl_get_acl(struct vnode *vp, acl_type_t type, struct acl *aclp)
  92 {
  93         struct thread *td = curthread;
  94         struct acl inkernelacl;
  95         struct ucred *ucred;
  96         int error;
  97
  98         ucred = td->td_ucred;
  99         error = VOP_GETACL(vp, type, &inkernelacl, ucred);
 100         if (error == 0)
 101                 error = copyout(&inkernelacl, aclp, sizeof(struct acl));
 102         return (error);
 103 }
 104
 105 /*
 106  * Given a vnode, delete its ACL.
 107  */
 108 static int
 109 vacl_delete(struct vnode *vp, acl_type_t type)
 110 {
 111         struct thread *td = curthread;
 112         struct ucred *ucred;
 113         int error;
 114
 115         ucred = td->td_ucred;
 116         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 117         error = VOP_SETACL(vp, ACL_TYPE_DEFAULT, 0, ucred);
 118         vn_unlock(vp);
 119         return (error);
 120 }
 121
 122 /*
 123  * Given a vnode, check whether an ACL is appropriate for it
 124  */
 125 static int
 126 vacl_aclcheck(struct vnode *vp, acl_type_t type, struct acl *aclp)
 127 {
 128         struct thread *td = curthread;
 129         struct ucred *ucred;
 130         struct acl inkernelacl;
 131         int error;
 132
 133         ucred = td->td_ucred;
 134         error = copyin(aclp, &inkernelacl, sizeof(struct acl));
 135         if (error)
 136                 return(error);
 137         error = VOP_ACLCHECK(vp, type, &inkernelacl, ucred);
 138         return (error);
 139 }
 140
 141 /*
 142  * syscalls -- convert the path/fd to a vnode, and call vacl_whatever.
 143  * Don't need to lock, as the vacl_ code will get/release any locks
 144  * required.
 145  */
 146
 147 /*
 148  * Given a file path, get an ACL for it
 149  */
 150 int
 151 sys___acl_get_file(struct __acl_get_file_args *uap)
 152 {
 153         struct nlookupdata nd;
 154         struct vnode *vp;
 155         int error;
 156
 157         vp = NULL;
 158         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 159         if (error == 0)
 160                 error = nlookup(&nd);
 161         if (error == 0)
 162                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 163         nlookup_done(&nd);
 164         if (error == 0) {
 165                 error = vacl_get_acl(vp, uap->type, uap->aclp);
 166                 vrele(vp);
 167         }
 168         return (error);
 169 }
 170
 171 /*
 172  * Given a file path, set an ACL for it
 173  */
 174 int
 175 sys___acl_set_file(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 __acl_get_fd_args *uap)
 200 {
 201         struct thread *td = curthread;
 202         struct file *fp;
 203         int error;
 204
 205         KKASSERT(td->td_proc);
 206         if ((error = holdvnode(td->td_proc->p_fd, 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 __acl_set_fd_args *uap)
 219 {
 220         struct thread *td = curthread;
 221         struct file *fp;
 222         int error;
 223
 224         KKASSERT(td->td_proc);
 225         if ((error = holdvnode(td->td_proc->p_fd, 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 __acl_delete_file_args *uap)
 237 {
 238         struct nlookupdata nd;
 239         struct vnode *vp;
 240         int error;
 241
 242         vp = NULL;
 243         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 244         if (error == 0)
 245                 error = nlookup(&nd);
 246         if (error == 0)
 247                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 248         nlookup_done(&nd);
 249
 250         if (error == 0) {
 251                 error = vacl_delete(vp, uap->type);
 252                 vrele(vp);
 253         }
 254         return (error);
 255 }
 256
 257 /*
 258  * Given a file path, delete an ACL from it.
 259  */
 260 int
 261 sys___acl_delete_fd(struct __acl_delete_fd_args *uap)
 262 {
 263         struct thread *td = curthread;
 264         struct file *fp;
 265         int error;
 266
 267         KKASSERT(td->td_proc);
 268         if ((error = holdvnode(td->td_proc->p_fd, uap->filedes, &fp)) != 0)
 269                 return(error);
 270         error = vacl_delete((struct vnode *)fp->f_data, uap->type);
 271         fdrop(fp);
 272         return (error);
 273 }
 274
 275 /*
 276  * Given a file path, check an ACL for it
 277  */
 278 int
 279 sys___acl_aclcheck_file(struct __acl_aclcheck_file_args *uap)
 280 {
 281         struct nlookupdata nd;
 282         struct vnode *vp;
 283         int error;
 284
 285         vp = NULL;
 286         error = nlookup_init(&nd, uap->path, UIO_USERSPACE, NLC_FOLLOW);
 287         if (error == 0)
 288                 error = nlookup(&nd);
 289         if (error == 0)
 290                 error = cache_vref(&nd.nl_nch, nd.nl_cred, &vp);
 291         nlookup_done(&nd);
 292
 293         if (error == 0) {
 294                 error = vacl_aclcheck(vp, uap->type, uap->aclp);
 295                 vrele(vp);
 296         }
 297         return (error);
 298 }
 299
 300 /*
 301  * Given a file descriptor, check an ACL for it
 302  */
 303 int
 304 sys___acl_aclcheck_fd(struct __acl_aclcheck_fd_args *uap)
 305 {
 306         struct thread *td = curthread;
 307         struct file *fp;
 308         int error;
 309
 310         KKASSERT(td->td_proc);
 311         if ((error = holdvnode(td->td_proc->p_fd, uap->filedes, &fp)) != 0)
 312                 return(error);
 313         error = vacl_aclcheck((struct vnode *)fp->f_data, uap->type, uap->aclp);
 314         fdrop(fp);
 315         return (error);
 316 }
 317