Re: bin/55815: tar opens device files

[David Holland <dholland-bugs%netbsd.org@localhost>]

The following reply was made to PR bin/55815; it has been noted by GNATS.

From: David Holland <dholland-bugs%netbsd.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: bin/55815: tar opens device files
Date: Fri, 4 Jun 2021 23:22:09 +0000

 On Fri, Jun 04, 2021 at 10:36:50PM +0200, Joerg Sonnenberger wrote:
  > >  However, it also seems foolish to pretend this is a real issue for
  > >  device nodes, so it seems like a perfectly adequate solution is for
  > >  tar to check for device nodes and not open them. Adding another open
  > >  mode seems like severe overkill. (O_NONBLOCK is sufficient for named
  > >  pipes.)
  > 
  > Checking for device nodes introduces TOCTOA problems though.
 
 Like I said, pretending that this is a real issue for device nodes is
 foolish. Use lstat (you have to anyway to tar up links); if it's a
 device, don't open it. Otherwise, open it with O_NOFOLLOW. If you then
 get a device anyway and your tape RAID starts rewinding 50 tapes at
 once, it's because root was screwing around. That's not our job to
 stop.
 
 -- 
 David A. Holland
 dholland%netbsd.org@localhost