Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Fri, 12 May 2017 16:20:31 -0700
From: Andy Lutomirski <>
To: Al Viro <>
Cc: Ingo Molnar <>, Andy Lutomirski <>, 
	Christoph Hellwig <>, Greg KH <>, Thomas Garnier <>, 
	Martin Schwidefsky <>, Heiko Carstens <>, 
	Dave Hansen <>, Arnd Bergmann <>, 
	Thomas Gleixner <>, David Howells <>, 
	René Nyffenegger <>, 
	Andrew Morton <>, 
	"Paul E . McKenney" <>, "Eric W . Biederman" <>, 
	Oleg Nesterov <>, Pavel Tikhomirov <>, 
	Ingo Molnar <>, "H . Peter Anvin" <>, Paolo Bonzini <>, 
	Rik van Riel <>, Kees Cook <>, 
	Josh Poimboeuf <>, Borislav Petkov <>, Brian Gerst <>, 
	"Kirill A . Shutemov" <>, 
	Christian Borntraeger <>, Russell King <>, 
	Will Deacon <>, Catalin Marinas <>, 
	Mark Rutland <>, James Morse <>, 
	linux-s390 <>, LKML <>, 
	Linux API <>, "the arch/x86 maintainers" <>, 
	"" <>, 
	Kernel Hardening <>, 
	Linus Torvalds <>, Peter Zijlstra <>
Subject: Re: Re: [PATCH v9 1/4] syscalls: Verify address
 limit before returning to user-mode

On Fri, May 12, 2017 at 12:15 AM, Al Viro <> wrote:

> Folks, seriously, have you even looked through that zoo?  I have, and it's
> really, really not fun.  Sure, we can say "fuck 'em, no need to allow
> splice() on random crap".  Would be perfectly reasonable, expect that
> it's not the only place doing kernel_write() and its ilk...

Can you clarify this?  I think we really may be able to do exactly
this.  From Christoph's list, there are only two things that need
kernel_read/kernel_write to user-supplied fds that may come from a
variety of sources: splice and exec.  If you're execing a chardev from
a crappy driver, something is seriously wrong.  And returning -EINVAL
from splice() to or from files that use ->read and ->write seems find
(and splice(2) even documents -EINVAL as meaning that the target
doesn't support splicing).


Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.