linux-kernel - Re: fanotify as syscalls

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <m1r5tzq1gf.fsf@fess.ebiederm.org>
Date:	Mon, 21 Sep 2009 17:15:28 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Jamie Lokier <jamie@...reable.org>,
	Evgeniy Polyakov <zbr@...emap.net>,
	Eric Paris <eparis@...hat.com>,
	David Miller <davem@...emloft.net>,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	netdev@...r.kernel.org, viro@...iv.linux.org.uk,
	alan@...ux.intel.com, hch@...radead.org
Subject: Re: fanotify as syscalls

Linus Torvalds <torvalds@...ux-foundation.org> writes:

> Quite frankly, I have _never_ever_ seen a good reason for talking to the 
> kernel with some idiotic packet interface. It's just a fancy way to do 
> ioctl's, and everybody knows that ioctl's are bad and evil. Why are fancy 
> packet interfaces suddenly much better?

For working with the networking stack there are a lot of advantages because
netlink is the interface to everything in the network stack.

There are nice things like the packet to create a new interface is the same
packet the kernel sends everyone to report a new interface etc.

netlink also seems to get the structured data thing right.  You can
parse the packet even if you don't understand everything.  Each tag is
well defined like a syscall, taking exactly one kind of argument.
Which avoids the worst failure of ioctl in that you can't even parse
everything, and the argument may be a linked list in the calling
process or something else atrocious.

All of that said syscalls are good, and I would not recommend netlink
to anything not in the network stack.

Eric
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/