Requesting a backport of SMB2/SMB3 bugfix for DFS support

[Nathan Neulinger]

16.04 x64 with 4.4.0-112 or 4.4.0-116 - cannot traverse a DFS link for a cifs.mount from windows if vers is anything other than 1.0 default. (This submission was from a 112 host, but it's confirmed to still exist on anything less than 4.11.)

Fix exists in 4.13.x in Ubuntu 18.x and works fine.

Issue is that once you mount with vers=2 or greater, you cannot traverse the dfs root directory to any file server, and you cannot mount the dfs path directly - only a direct mount to the backend fileservers will work.

Requesting a backport of the fix as described below as this makes it impossible to move forward with security action disabling SMB1 on our windows environment. If we do that now, will be unable to use that storage from all of our windows systems without directly mapping to individual file servers.

https://www.spinics.net/lists/linux-cifs/msg13825.html

1: https://bugzilla.samba.org/show_bug.cgi?id=12917

Aurelien Aptel (3):
  CIFS: set SERVER_NAME_LENGTH to serverName actual size
  CIFS: make IPC a regular tcon
  CIFS: use tcon_ipc instead of use_ipc parameter from SMB2_ioctl

It's unclear if this should be treated as a security issue since it's not directly a security problem itself, but rather prevents taking security related action.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-generic 4.4.0.112.118
ProcVersionSignature: Ubuntu 4.4.0-112.135-generic 4.4.98
Uname: Linux 4.4.0-112-generic x86_64
AlsaDevices:
 total 0
 crw-rw---- 1 root audio 116, 1 Feb 8 23:26 seq
 crw-rw---- 1 root audio 116, 33 Feb 8 23:26 timer
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay'
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord'
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
Date: Tue Mar 6 10:29:20 2018
HibernationDevice: RESUME=/dev/mapper/main-swap
IwConfig: Error: [Errno 2] No such file or directory: 'iwconfig'
Lsusb: Error: command ['lsusb'] failed with exit code 1:
MachineType: VMware, Inc. VMware Virtual Platform
PciMultimedia:

ProcFB: 0 svgadrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-112-generic root=/dev/mapper/main-root ro
RelatedPackageVersions:
 linux-restricted-modules-4.4.0-112-generic N/A
 linux-backports-modules-4.4.0-112-generic N/A
 linux-firmware 1.157.15
RfKill: Error: [Errno 2] No such file or directory: 'rfkill'
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 09/21/2015
dmi.bios.vendor: Phoenix Technologies LTD
dmi.bios.version: 6.00
dmi.board.name: 440BX Desktop Reference Platform
dmi.board.vendor: Intel Corporation
dmi.board.version: None
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 1
dmi.chassis.vendor: No Enclosure
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnPhoenixTechnologiesLTD:bvr6.00:bd09/21/2015:svnVMware,Inc.:pnVMwareVirtualPlatform:pvrNone:rvnIntelCorporation:rn440BXDesktopReferencePlatform:rvrNone:cvnNoEnclosure:ct1:cvrN/A:
dmi.product.name: VMware Virtual Platform
dmi.product.version: None
dmi.sys.vendor: VMware, Inc.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.