FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_acl.c

     /*-
      * Copyright (c) 1999, 2000 Robert N. M. Watson
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     * $FreeBSD$
     */
    
    /*
     * Generic routines to support file system ACLs, at a syntactic level
     * Semantics are the responsibility of the underlying file system
     */
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/sysproto.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/vnode.h>
    #include <sys/lock.h>
    #include <sys/namei.h>
    #include <sys/file.h>
    #include <sys/proc.h>
    #include <sys/sysent.h>
    #include <sys/errno.h>
    #include <sys/stat.h>
    #include <sys/acl.h>
    
    static MALLOC_DEFINE(M_ACL, "acl", "access control list");
    
    static int      vacl_set_acl(struct proc *p, struct vnode *vp, acl_type_t type,
                struct acl *aclp);
    static int      vacl_get_acl(struct proc *p, struct vnode *vp, acl_type_t type,
                struct acl *aclp);
    static int      vacl_aclcheck(struct proc *p, struct vnode *vp, acl_type_t type,
                struct acl *aclp);
    
    /*
     * These calls wrap the real vnode operations, and are called by the 
     * syscall code once the syscall has converted the path or file
     * descriptor to a vnode (unlocked).  The aclp pointer is assumed
     * still to point to userland, so this should not be consumed within
     * the kernel except by syscall code.  Other code should directly
     * invoke VOP_{SET,GET}ACL.
     */
    
    /*
     * Given a vnode, set its ACL.
     */
    static int
    vacl_set_acl(struct proc *p, struct vnode *vp, acl_type_t type,
        struct acl *aclp)
    {
            struct acl inkernacl;
            int error;
    
            error = copyin(aclp, &inkernacl, sizeof(struct acl));
            if (error)
                    return(error);
            VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
            vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
            error = VOP_SETACL(vp, type, &inkernacl, p->p_ucred, p);
            VOP_UNLOCK(vp, 0, p);
            return(error);
    }
    
    /*
     * Given a vnode, get its ACL.
     */
    static int
    vacl_get_acl(struct proc *p, struct vnode *vp, acl_type_t type,
        struct acl *aclp)
    {
            struct acl inkernelacl;
            int error;
    
            error = VOP_GETACL(vp, type, &inkernelacl, p->p_ucred, p);
            if (error == 0)
                    error = copyout(&inkernelacl, aclp, sizeof(struct acl));
           return (error);
   }
   
   /*
    * Given a vnode, delete its ACL.
    */
   static int
   vacl_delete(struct proc *p, struct vnode *vp, acl_type_t type)
   {
           int error;
   
           VOP_LEASE(vp, p, p->p_ucred, LEASE_WRITE);
           vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
           error = VOP_SETACL(vp, ACL_TYPE_DEFAULT, 0, p->p_ucred, p);
           VOP_UNLOCK(vp, 0, p);
           return (error);
   }
   
   /*
    * Given a vnode, check whether an ACL is appropriate for it
    */
   static int
   vacl_aclcheck(struct proc *p, struct vnode *vp, acl_type_t type,
       struct acl *aclp)
   {
           struct acl inkernelacl;
           int error;
   
           error = copyin(aclp, &inkernelacl, sizeof(struct acl));
           if (error)
                   return(error);
           error = VOP_ACLCHECK(vp, type, &inkernelacl, p->p_ucred, p);
           return (error);
   }
   
   /*
    * syscalls -- convert the path/fd to a vnode, and call vacl_whatever.
    * Don't need to lock, as the vacl_ code will get/release any locks
    * required.
    */
   
   /*
    * Given a file path, get an ACL for it
    */
   int
   __acl_get_file(struct proc *p, struct __acl_get_file_args *uap)
   {
           struct nameidata nd;
           int error;
   
           /* what flags are required here -- possible not LOCKLEAF? */
           NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
           error = namei(&nd);
           if (error)
                   return(error);
           error = vacl_get_acl(p, nd.ni_vp, SCARG(uap, type), SCARG(uap, aclp));
           NDFREE(&nd, 0);
           return (error);
   }
   
   /*
    * Given a file path, set an ACL for it
    */
   int
   __acl_set_file(struct proc *p, struct __acl_set_file_args *uap)
   {
           struct nameidata nd;
           int error;
   
           NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
           error = namei(&nd);
           if (error)
                   return(error);
           error = vacl_set_acl(p, nd.ni_vp, SCARG(uap, type), SCARG(uap, aclp));
           NDFREE(&nd, 0);
           return (error);
   }
   
   /*
    * Given a file descriptor, get an ACL for it
    */
   int
   __acl_get_fd(struct proc *p, struct __acl_get_fd_args *uap)
   {
           struct file *fp;
           int error;
   
           error = getvnode(p->p_fd, SCARG(uap, filedes), &fp);
           if (error)
                   return(error);
           return vacl_get_acl(p, (struct vnode *)fp->f_data, SCARG(uap, type),
               SCARG(uap, aclp));
   }
   
   /*
    * Given a file descriptor, set an ACL for it
    */
   int
   __acl_set_fd(struct proc *p, struct __acl_set_fd_args *uap)
   {
           struct file *fp;
           int error;
   
           error = getvnode(p->p_fd, SCARG(uap, filedes), &fp);
           if (error)
                   return(error);
           return vacl_set_acl(p, (struct vnode *)fp->f_data, SCARG(uap, type),
               SCARG(uap, aclp));
   }
   
   /*
    * Given a file path, delete an ACL from it.
    */
   int
   __acl_delete_file(struct proc *p, struct __acl_delete_file_args *uap)
   {
           struct nameidata nd;
           int error;
   
           NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
           error = namei(&nd);
           if (error)
                   return(error);
           error = vacl_delete(p, nd.ni_vp, SCARG(uap, type));
           NDFREE(&nd, 0);
           return (error);
   }
   
   /*
    * Given a file path, delete an ACL from it.
    */
   int
   __acl_delete_fd(struct proc *p, struct __acl_delete_fd_args *uap)
   {
           struct file *fp;
           int error;
   
           error = getvnode(p->p_fd, SCARG(uap, filedes), &fp);
           if (error)
                   return(error);
           error = vacl_delete(p, (struct vnode *)fp->f_data, SCARG(uap, type));
           return (error);
   }
   
   /*
    * Given a file path, check an ACL for it
    */
   int
   __acl_aclcheck_file(struct proc *p, struct __acl_aclcheck_file_args *uap)
   {
           struct nameidata        nd;
           int     error;
   
           NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
           error = namei(&nd);
           if (error)
                   return(error);
           error = vacl_aclcheck(p, nd.ni_vp, SCARG(uap, type), SCARG(uap, aclp));
           NDFREE(&nd, 0);
           return (error);
   }
   
   /*
    * Given a file descriptor, check an ACL for it
    */
   int
   __acl_aclcheck_fd(struct proc *p, struct __acl_aclcheck_fd_args *uap)
   {
           struct file *fp;
           int error;
   
           error = getvnode(p->p_fd, SCARG(uap, filedes), &fp);
           if (error)
                   return(error);
           return vacl_aclcheck(p, (struct vnode *)fp->f_data, SCARG(uap, type),
               SCARG(uap, aclp));
   }

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