[PATCH] ioctl_tty.2: add TIOCGPTPEER documentation
asarai at suse.de
Wed Aug 16 04:43:29 UTC 2017
> I've applied this patch, and then tweaked the wording a little. Could
> you please check the following text:
> TIOCGPTPEER int flags
> (since Linux 4.13) Given a file descriptor in fd that
> refers to a pseudoterminal master, open (with the given
> open(2)-style flags) and return a new file descriptor that
> refers to the peer pseudoterminal slave device. This oper‐
> ation can be performed regardless of whether the pathname
> of the slave device is accessible through the calling
> process's mount namespaces.
> Security-conscious programs interacting with namespaces may
> wish to use this operation rather than open(2) with the
> pathname returned by ptsname(3), and similar library func‐
> tions that have insecure APIs.
Yup, that sounds good.
> I also have a question on the last sentence: what are the "similar library
> functions that have insecure APIs"? It's not clear to me what you are
> referring to here.
There are a few posix_-style functions provided by glibc that are just
wrappers around the open+ptsname combo that I mention earlier in the
sentence (and thus are vulnerable to the same issue). But if you feel
it's confusing you can feel free to drop it.
Software Engineer (Containers)
SUSE Linux GmbH
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