From: Matthias Lederhofer <matled@gmx.net>
Date: Thu, 13 Jul 2006 16:03:26 GMT
Subject: Re: [PATCH 2/5] daemon: if one of the standard fds is missing open it to /dev/null
Message-ID: <E1G13ew-0005Iv-ST@moooo.ath.cx>
In-Reply-To: <118833cc0607130837u30c58d53lc785f56d45ef970c@mail.gmail.com>

Morten Welinder <mwelinder@gmail.com> wrote:
> >+               if (devnull == -1 &&
> >+                       (devnull = open("/dev/null", O_RDWR, 0)) == -1)
> >+                       die("open /dev/null failed: %s", strerror(errno));
> >+               if (dup2(devnull, i) != i)
> >+                       die("dup2 failed: %s", strerror(errno));
> 
> "die" probably won't work well at this point.
At least with --syslog there will be an error message in the logs.
If the user does not use --syslog and closes fd 2 it is just his own
fault imho.

> Should git (and most other programs) do something like this in general?
> fprintf will happily write to fd=2 regardless of whether that is some critical
> file you opened.
I thought of that too.  It might be not that important because I
cannot think of anyway that this could happen accidentally or could be
exploited.