On Tue, May 9, 2017 at 9:03 AM, Christoph Hellwig [off-list ref] wrote:

On Tue, May 09, 2017 at 06:02:50AM -0700, Christoph Hellwig wrote:

quoted

On Tue, May 09, 2017 at 06:00:01AM -0700, Andy Lutomirski wrote:

quoted

fs/splice.c has some, ahem, interesting uses that have been the source
of nasty exploits in the past.  Converting them to use iov_iter
properly would be really, really nice.  Christoph, I don't suppose
you'd like to do that?

I can take care of all the fs code including this one.

I spent the afternoon hacking up where I'd like this to head.  It's
completely untested as of now:

        http://git.infradead.org/users/hch/vfs.git/shortlog/refs/heads/setfs-elimination

Ooooh yes! Nice work.

I love this:
http://git.infradead.org/users/hch/vfs.git/commitdiff/51e83f50f824ca23f5584c172138e6b7c2ff786d
but I wonder what it'll cause out-of-tree code to do. I mean, I'd
rather nothing out-of-tree be calling these, but I'd hate 3rd party
hacks even more.

http://git.infradead.org/users/hch/vfs.git/commitdiff/018e0e9030777121fe87e89d43066691e7366587
This accidentally(?) removes the kernel-doc comments.

http://git.infradead.org/users/hch/vfs.git/commitdiff/78b62c730254fc39fa888cdbdca08fde6e09a798
Could this be made defensive? (Return 0 if ret wraps, for example?) I
see what the comment says, but not everyone will read that. :(

http://git.infradead.org/users/hch/vfs.git/commitdiff/a106276ca0294be054bc89ce97219933fe543df1
Perhaps unconditionally set USER_DS on exit instead of retaining
whatever was there?

-Kees

-- 
Kees Cook
Pixel Security