Just got a wireshark trace - this is a fairly trivial issue (missing the validate negotiate must be signed patch) - I had some trouble getting this version of the kernel running (unrelated issue) and on systems with access to Windows 2016... On Tue, Feb 27, 2018 at 10:33 AM, Srivatsa S. Bhat <srivatsa@xxxxxxxxxxxxx> wrote: > On 2/27/18 9:56 AM, Steve French wrote: >> 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. >> > > If you have the proposed patches that apply on 4.9, I'd be happy to > try them out! > > [ I would have offered to backport the patches myself, but actually I > already tried doing that with a larger set of patches from mainline > (picking those commits between the regression and the fix that seemed > relevant), but I felt quite out-of-depth trying to adapt them to 4.9 > and 4.4, as I'm not that familiar with the internals of SMB/CIFS. ] > >> 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 >> > > Yep! > > Regards, > Srivatsa > >> 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