> On Sat, Apr 15, 2017 at 10:27:19PM +0200, Matthieu Herrb wrote:
> > On 6.1 and -current. run 'pax' without any argment.
> >
> > $ pax
> > Abort (core dumped)
> > Exit 134
> >
> > $ dmesg | tail -1
> > pax(81327): syscall 54 "tty"
> >
> > $ ktrace pax
> > $ kdump | tail -4
> > 19681 pax CALL ioctl(0,MTIOCGET,0x7f7ffffbd7f0)
> > 19681 pax PLDG ioctl, "tty", errno 1 Operation not permitted
> > 19681 pax PSIG SIGABRT SIG_DFL
> > 19681 pax NAMI "pax.core"
> >
> > --
> > Matthieu Herrb
> >
>
> The issue here is, that pledge("tape") does not allow to perform
> MTIOCGET on tty devices. So we should call isatty() beforehand and
> shortcut ioctl() in case the file descriptor is a tty.
>
> Index: ar_io.c
> ===================================================================
> RCS file: /cvs/src/bin/pax/ar_io.c,v
> retrieving revision 1.62
> diff -u -p -r1.62 ar_io.c
> --- ar_io.c 11 Mar 2017 12:55:47 -0000 1.62
> +++ ar_io.c 16 Apr 2017 07:08:29 -0000
> @@ -170,9 +170,12 @@ ar_open(const char *name)
> return(-1);
> }
>
> - if (S_ISCHR(arsb.st_mode))
> - artyp = ioctl(arfd, MTIOCGET, &mb) ? ISCHR : ISTAPE;
> - else if (S_ISBLK(arsb.st_mode))
> + if (S_ISCHR(arsb.st_mode)) {
> + if (isatty(arfd) || ioctl(arfd, MTIOCGET, &mb))
> + artyp = ISCHR;
> + else
> + artyp = ISTAPE;
> + } else if (S_ISBLK(arsb.st_mode))
> artyp = ISBLK;
> else if ((lseek(arfd, 0, SEEK_CUR) == -1) && (errno == ESPIPE))
> artyp = ISPIPE;
>
>
> With this diff applied:
>
> $ pax
> [waiting for input]
> ...
What about cdevs which are not tty, but also not tape.
I am quite averse to pledge inserting errnos rather than failure
because it creates a "posix variant" rather than "enforcement",
however I was wondering about doing a bit different here since the
tape ioctl's are not really POSIX.
Index: kern_pledge.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_pledge.c,v
retrieving revision 1.203
diff -u -p -u -r1.203 kern_pledge.c
--- kern_pledge.c 13 Apr 2017 04:06:46 -0000 1.203
+++ kern_pledge.c 15 Apr 2017 22:28:54 -0000
@@ -1155,9 +1155,12 @@ pledge_ioctl(struct proc *p, long com, s
case MTIOCTOP:
/* for pax(1) and such, checking tapes... */
if (fp->f_type == DTYPE_VNODE &&
- vp->v_type == VCHR &&
- (vp->v_flag & VISTTY) == 0)
- return (0);
+ vp->v_type == VCHR) {
+ if (vp->v_flag & VISTTY)
+ return (ENOTTY);
+ else
+ return (0);
+ }
break;
}
}
