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Remove tun_proc; replace with tun_pid. tun_proc pointer may be stale

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as the process that opens tun_softc can exit before the file
descriptor is closed.

Taiwan experience provided by:	keichii
Crashing breakers provided by:	Chia-liang Kao <clkao@clkao.org>
This commit is contained in:
Robert Watson 2004-03-17 01:12:09 +00:00
parent 7c924a5287
commit 25f740b790
1 changed files with 14 additions and 7 deletions
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21
sys/net/if_tun.c
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@ -71,7 +71,14 @@ struct tun_softc {
#define TUN_READY (TUN_OPEN | TUN_INITED)
struct proc *tun_proc; /* Owning process */
/*
* XXXRW: tun_pid is used to exclusively lock /dev/tun. Is this
* actually needed? Can we just return EBUSY if already open?
* Problem is that this involved inherent races when a tun device
* is handed off from one process to another, as opposed to just
* being slightly stale informationally.
*/
pid_t tun_pid; /* owning pid */
struct ifnet tun_if; /* the interface */
struct sigio *tun_sigio; /* information for async I/O */
struct selinfo tun_rsel; /* read select */
@ -237,9 +244,9 @@ tunopen(dev_t dev, int flag, int mode, struct thread *td)
tp = dev->si_drv1;
}
if (tp->tun_proc != NULL && tp->tun_proc != td->td_proc)
if (tp->tun_pid != 0 && tp->tun_pid != td->td_proc->p_pid)
return (EBUSY);
tp->tun_proc = td->td_proc;
tp->tun_pid = td->td_proc->p_pid;
tp->tun_flags |= TUN_OPEN;
ifp = &tp->tun_if;
@ -263,7 +270,7 @@ tunclose(dev_t dev, int foo, int bar, struct thread *td)
ifp = &tp->tun_if;
tp->tun_flags &= ~TUN_OPEN;
tp->tun_proc = NULL;
tp->tun_pid = 0;
/*
* junk all pending output
@ -346,9 +353,9 @@ tunifioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
switch(cmd) {
case SIOCGIFSTATUS:
ifs = (struct ifstat *)data;
if (tp->tun_proc)
if (tp->tun_pid)
sprintf(ifs->ascii + strlen(ifs->ascii),
"\tOpened by PID %d\n", tp->tun_proc->p_pid);
"\tOpened by PID %d\n", tp->tun_pid);
break;
case SIOCSIFADDR:
error = tuninit(ifp);
@ -535,7 +542,7 @@ tunioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct thread *td)
}
break;
case TUNSIFPID:
tp->tun_proc = curthread->td_proc;
tp->tun_pid = curthread->td_proc->p_pid;
break;
case FIONBIO:
break;