This shouldn't be too hard to figure out if willing to backport a slightly larger set of fixes to the older stable, but I don't have a system running 4.9 stable. Is this the correct stable tree branch? https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/log/?h=linux-4.9.y On Tue, Feb 27, 2018 at 11:45 AM, Srivatsa S. Bhat <srivatsa@xxxxxxxxxxxxx> wrote: > On 2/27/18 4:40 AM, Greg Kroah-Hartman wrote: >> On Tue, Feb 27, 2018 at 01:22:31AM -0800, Srivatsa S. Bhat wrote: >>> On 2/27/18 12:54 AM, Greg Kroah-Hartman wrote: >>>> On Mon, Feb 26, 2018 at 07:44:28PM -0800, Srivatsa S. Bhat wrote: >>>>> On 1/3/18 6:15 PM, Srivatsa S. Bhat wrote: >>>>>> On 11/1/17 8:18 AM, Greg Kroah-Hartman wrote: >>>>>>> On Tue, Oct 31, 2017 at 03:02:11PM +0200, Thomas Backlund wrote: >>>>>>>> Den 31.10.2017 kl. 11:55, skrev Greg Kroah-Hartman: >>>>>>>>> 4.13-stable review patch. If anyone has any objections, please let me know. >>>>>>>>> >>>>>>>>> ------------------ >>>>>>>>> >>>>>>>>> From: Steve French <smfrench@xxxxxxxxx> >>>>>>>>> >>>>>>>>> commit 4587eee04e2ac7ac3ac9fa2bc164fb6e548f99cd upstream. >>>>>>>>> >>>>>>>>> According to MS-SMB2 3.2.55 validate_negotiate request must >>>>>>>>> always be signed. Some Windows can fail the request if you send it unsigned >>>>>>>>> >>>>>>>>> See kernel bugzilla bug 197311 >>>>>>>>> >>>>>>>>> Acked-by: Ronnie Sahlberg <lsahlber.redhat.com> >>>>>>>>> Signed-off-by: Steve French <smfrench@xxxxxxxxx> >>>>>>>>> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> >>>>>>>>> >>>>>>>>> --- >>>>>>>>> fs/cifs/smb2pdu.c | 3 +++ >>>>>>>>> 1 file changed, 3 insertions(+) >>>>>>>>> >>>>>>>>> --- a/fs/cifs/smb2pdu.c >>>>>>>>> +++ b/fs/cifs/smb2pdu.c >>>>>>>>> @@ -1963,6 +1963,9 @@ SMB2_ioctl(const unsigned int xid, struc >>>>>>>>> } else >>>>>>>>> iov[0].iov_len = get_rfc1002_length(req) + 4; >>>>>>>>> + /* validate negotiate request must be signed - see MS-SMB2 3.2.5.5 */ >>>>>>>>> + if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO) >>>>>>>>> + req->hdr.sync_hdr.Flags |= SMB2_FLAGS_SIGNED; >>>>>>>>> rc = SendReceive2(xid, ses, iov, n_iov, &resp_buftype, flags, &rsp_iov); >>>>>>>>> cifs_small_buf_release(req); >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>>> This one needs to be backported to all stable kernels as the commit that >>>>>>>> introduced the regression: >>>>>>>> ' >>>>>>>> 0603c96f3af50e2f9299fa410c224ab1d465e0f9 >>>>>>>> SMB: Validate negotiate (to protect against downgrade) even if signing off >>>>>>>> >>>>>>>> is backported in stable trees as of: 4.9.53, 4.4.90, 3.18.73 >>>>>>> >>>>>>> Oh wait, it breaks the builds on older kernels, that's why I didn't >>>>>>> apply it :) >>>>>>> >>>>>>> Can you provide me with a working backport? >>>>>>> >>>>>> >>>>>> Hi Steve, >>>>>> >>>>>> Is there a version of this fix available for stable kernels? >>>>>> >>>>> >>>>> Hi Greg, >>>>> >>>>> Mounting SMB3 shares continues to fail for me on 4.4.118 and 4.9.84 >>>>> due to the issues that I have described in detail on this mail thread. >>>>> >>>>> Since there is no apparent fix for this bug on stable kernels, could >>>>> you please consider reverting the original commit that caused this >>>>> regression? >>>>> >>>>> That commit was intended to enhance security, which is probably why it >>>>> was backported to stable kernels in the first place; but instead it >>>>> ends up breaking basic functionality itself (mounting). So in the >>>>> absence of a proper fix, I don't see much of an option but to revert >>>>> that commit. >>>>> >>>>> So, please consider reverting the following: >>>>> >>>>> commit 02ef29f9cbb616bf419 "SMB: Validate negotiate (to protect >>>>> against downgrade) even if signing off" on 4.4.118 >>>>> >>>>> commit 0e1b85a41a25ac888fb "SMB: Validate negotiate (to protect >>>>> against downgrade) even if signing off" on 4.9.84 >>>>> >>>>> They correspond to commit 0603c96f3af50e2f9299fa410c224ab1d465e0f9 >>>>> upstream. Both these patches should revert cleanly. >>>> >>>> Do you still have this same problem on 4.14 and 4.15? If so, the issue >>>> needs to get fixed there, not papered-over by reverting these old >>>> changes, as you will hit the issue again in the future when you update >>>> to a newer kernel version. >>>> >>> >>> 4.14 and 4.15 work great! (I had mentioned this is in my original bug >>> report but forgot to summarize it here, sorry). >> >> >> Then what is the bugfix that should be applied here in order to keep >> things working with these patches applied? >> > > That would be the one mentioned in the subject line of this thread :) > However, a working backport of that fix is not available for 4.4 and > 4.9, hence the trouble. > > It looks like we are reconstructing elements of this email thread all > over again, so let me quickly summarize the status so far: > > In 4.14/4.15/mainline, > - commit 0603c96f3af50e2f9 (SMB: Validate negotiate (to protect against > downgrade) even if signing off) caused mount regression with SMB v3. > > - commit 4587eee04e2ac7ac3 (SMB3: Validate negotiate request must > always be signed) fixed the issue. > > - [ There was a lot of code churn in the CIFS/SMB codebase between > these two commits in mainline. ] > > In this email thread, you backported the fix to stable 4.13. Thomas > noticed that the problematic commit had also made it to stable series > such as 4.4 and 4.9, and requested a backport of the fix to those > trees as well. However, a straight-forward backport of the fix to 4.4 > and 4.9 breaks the build, so no fix was available for those kernels. > > I investigated this and tried to produce a working backport of the fix > to 4.4 and 4.9, but didn't succeed, despite trying several variations > as well as suggestions from Aurelien [1][2]. So, given that there is > still no known fix for the mount regression on 4.4 and 4.9 stable > series at this point, I decided to request a revert of the problematic > commit that caused the regression in those kernels. > > [1]. https://lkml.org/lkml/2018/1/3/892 > [2]. https://lkml.org/lkml/2018/1/29/1009 > > Regards, > Srivatsa -- Thanks, Steve