Re: how does O_NOCTTY help? [Re: bug in chdir-safer

[Paul Eggert]

Jim Meyering <address@hidden> writes:

> how can setting the controlling terminal cause trouble if we're
> guaranteed never to read from or write to the corresponding file
> descriptor.

Once the terminal controls you, someone typing Control-C on that
terminal can send you a signal, even if you're not reading or writing
to the corresponding file descriptor.  On hosts where O_NOCTTY is
significant, and which do not support O_DIRECTORY (Solaris, for
example), this can cause an attacker to kill a seemingly-unrelated
directory-traversal process.