Re: RFC: Revert move default dialect from CIFS to to SMB3

[Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Thu, 2017-08-31 at 21:42 -0500, Steve French wrote:
> Any thoughts on this patch to add additional warnings for the user -
> logging when using default dialects (or when server returns dialect
> not supported), and noting the default dialect change?
> 
> See https://git.samba.org/?p=sfrench/cifs-2.6.git;a=commit;h=bb86f22eeddbb5879675b55168b8fa8990d74a21
> 

Breaking backward compatability sucks, but I agree that there's no real
alternative here. SMB1 is just not a safe default these days.

> On Thu, Aug 31, 2017 at 7:29 PM, Steve French <smfrench-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> > Yes - updating the parsing slightly and printks as suggested makes sense
> > 
> > Some additional warning messages in the userspace helper (adding Jeff
> > Layton), mount.cifs can also help.
> > 

What do you suggest here?

> > I also have an experimental set of patches to allow multi-dialect
> > negotiation with at least three of the acceptable dialects
> > (smb2.1/smb3/smb3.02) which will help, but complicate secure dialect
> > validation ("validate negotiate") but that will have to wait till next
> > release.
> > 

That seems like the best way to fix this. If you fail to negotiate any
dialect, throw a warning then.


> > On Thu, Aug 31, 2017 at 7:12 PM, Linus Torvalds
> > <torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> wrote:
> > > On Thu, Aug 31, 2017 at 2:36 PM, Thorsten Leemhuis <linux-rCxcAJFjeRkk+I/owrrOrA@public.gmane.org> wrote:
> > > > Lo! To give a bit more background to this (the mail I reply to was the
> > > > first I sent with git send-email and I missed some details): Maybe I'm
> > > > over stretching my abilities/position as regression tracker with this
> > > > RFC for a revert, but I hope it at least triggers a discussion if such a
> > > > revert should be done or not.
> > > 
> > > I don't think that a revert is appropriate.
> > > 
> > > But perhaps just a single printk() or something if the user does *not*
> > > specify the version explicitly? Just saying something like
> > > 
> > >   We used to default to 1.0, we now default to 3.0, if you want old
> > > defaults, use "vers=1.0"
> > > 
> > > Oh, looking at that version parsing code, I think we also need to fix
> > > that legacy "ver=1" thing (ver without the 's') which now silently
> > > ignores "ver=1" as being the "default", even though it's not.
> > > 
> > > I do *not* believe that "default to version 1" is acceptable.
> > > 
> > >                 Linus
> > 
> > 
> > 
> > --
> > Thanks,
> > 
> > Steve
> 
> 
> 

-- 
Jeff Layton <jlayton-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>