freebsd-skq/sys/kern/sys_socket.c
Robert Watson 9ca435893b In order to better support flexible and extensible access control,
make a series of modifications to the credential arguments relating
to file read and write operations to cliarfy which credential is
used for what:

- Change fo_read() and fo_write() to accept "active_cred" instead of
  "cred", and change the semantics of consumers of fo_read() and
  fo_write() to pass the active credential of the thread requesting
  an operation rather than the cached file cred.  The cached file
  cred is still available in fo_read() and fo_write() consumers
  via fp->f_cred.  These changes largely in sys_generic.c.

For each implementation of fo_read() and fo_write(), update cred
usage to reflect this change and maintain current semantics:

- badfo_readwrite() unchanged
- kqueue_read/write() unchanged
  pipe_read/write() now authorize MAC using active_cred rather
  than td->td_ucred
- soo_read/write() unchanged
- vn_read/write() now authorize MAC using active_cred but
  VOP_READ/WRITE() with fp->f_cred

Modify vn_rdwr() to accept two credential arguments instead of a
single credential: active_cred and file_cred.  Use active_cred
for MAC authorization, and select a credential for use in
VOP_READ/WRITE() based on whether file_cred is NULL or not.  If
file_cred is provided, authorize the VOP using that cred,
otherwise the active credential, matching current semantics.

Modify current vn_rdwr() consumers to pass a file_cred if used
in the context of a struct file, and to always pass active_cred.
When vn_rdwr() is used without a file_cred, pass NOCRED.

These changes should maintain current semantics for read/write,
but avoid a redundant passing of fp->f_cred, as well as making
it more clear what the origin of each credential is in file
descriptor read/write operations.

Follow-up commits will make similar changes to other file descriptor
operations, and modify the MAC framework to pass both credentials
to MAC policy modules so they can implement either semantic for
revocation.

Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, NAI Labs
2002-08-15 20:55:08 +00:00

218 lines
5.7 KiB
C

/*
* Copyright (c) 1982, 1986, 1990, 1993
* The Regents of the University of California. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* @(#)sys_socket.c 8.1 (Berkeley) 6/10/93
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/file.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/filio.h> /* XXX */
#include <sys/sockio.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <sys/filedesc.h>
#include <sys/ucred.h>
#include <net/if.h>
#include <net/route.h>
struct fileops socketops = {
soo_read, soo_write, soo_ioctl, soo_poll, sokqfilter,
soo_stat, soo_close
};
/* ARGSUSED */
int
soo_read(fp, uio, active_cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *active_cred;
struct thread *td;
int flags;
{
struct socket *so = (struct socket *)fp->f_data;
int error;
mtx_lock(&Giant);
error = so->so_proto->pr_usrreqs->pru_soreceive(so, 0, uio, 0, 0, 0);
mtx_unlock(&Giant);
return (error);
}
/* ARGSUSED */
int
soo_write(fp, uio, active_cred, flags, td)
struct file *fp;
struct uio *uio;
struct ucred *active_cred;
struct thread *td;
int flags;
{
struct socket *so = (struct socket *)fp->f_data;
int error;
mtx_lock(&Giant);
error = so->so_proto->pr_usrreqs->pru_sosend(so, 0, uio, 0, 0, 0,
uio->uio_td);
mtx_unlock(&Giant);
return (error);
}
int
soo_ioctl(fp, cmd, data, td)
struct file *fp;
u_long cmd;
void *data;
struct thread *td;
{
register struct socket *so = (struct socket *)fp->f_data;
switch (cmd) {
case FIONBIO:
if (*(int *)data)
so->so_state |= SS_NBIO;
else
so->so_state &= ~SS_NBIO;
return (0);
case FIOASYNC:
if (*(int *)data) {
so->so_state |= SS_ASYNC;
so->so_rcv.sb_flags |= SB_ASYNC;
so->so_snd.sb_flags |= SB_ASYNC;
} else {
so->so_state &= ~SS_ASYNC;
so->so_rcv.sb_flags &= ~SB_ASYNC;
so->so_snd.sb_flags &= ~SB_ASYNC;
}
return (0);
case FIONREAD:
*(int *)data = so->so_rcv.sb_cc;
return (0);
case FIOSETOWN:
return (fsetown(*(int *)data, &so->so_sigio));
case FIOGETOWN:
*(int *)data = fgetown(so->so_sigio);
return (0);
case SIOCSPGRP:
return (fsetown(-(*(int *)data), &so->so_sigio));
case SIOCGPGRP:
*(int *)data = -fgetown(so->so_sigio);
return (0);
case SIOCATMARK:
*(int *)data = (so->so_state&SS_RCVATMARK) != 0;
return (0);
}
/*
* Interface/routing/protocol specific ioctls:
* interface and routing ioctls should have a
* different entry since a socket's unnecessary
*/
if (IOCGROUP(cmd) == 'i')
return (ifioctl(so, cmd, data, td));
if (IOCGROUP(cmd) == 'r')
return (rtioctl(cmd, data));
return ((*so->so_proto->pr_usrreqs->pru_control)(so, cmd, data, 0, td));
}
int
soo_poll(fp, events, cred, td)
struct file *fp;
int events;
struct ucred *cred;
struct thread *td;
{
struct socket *so = (struct socket *)fp->f_data;
return so->so_proto->pr_usrreqs->pru_sopoll(so, events, cred, td);
}
int
soo_stat(fp, ub, td)
struct file *fp;
struct stat *ub;
struct thread *td;
{
struct socket *so = (struct socket *)fp->f_data;
bzero((caddr_t)ub, sizeof (*ub));
ub->st_mode = S_IFSOCK;
/*
* If SS_CANTRCVMORE is set, but there's still data left in the
* receive buffer, the socket is still readable.
*/
if ((so->so_state & SS_CANTRCVMORE) == 0 ||
so->so_rcv.sb_cc != 0)
ub->st_mode |= S_IRUSR | S_IRGRP | S_IROTH;
if ((so->so_state & SS_CANTSENDMORE) == 0)
ub->st_mode |= S_IWUSR | S_IWGRP | S_IWOTH;
ub->st_size = so->so_rcv.sb_cc;
ub->st_uid = so->so_cred->cr_uid;
ub->st_gid = so->so_cred->cr_gid;
return ((*so->so_proto->pr_usrreqs->pru_sense)(so, ub));
}
/*
* API socket close on file pointer. We call soclose() to close the
* socket (including initiating closing protocols). soclose() will
* sorele() the file reference but the actual socket will not go away
* until the socket's ref count hits 0.
*/
/* ARGSUSED */
int
soo_close(fp, td)
struct file *fp;
struct thread *td;
{
int error = 0;
struct socket *so;
so = (struct socket *)fp->f_data;
fp->f_ops = &badfileops;
fp->f_data = 0;
if (so)
error = soclose(so);
return (error);
}