Description of problem: Attempting to mount a DFS CIFS share with mount.cifs fails with "mount error(95): Operation not supported" when using the sec= mount option. Version-Release number of selected component (if applicable): Tested: 2.6.32-431.1.2.el6.x86_64 & 2.6.32-504.8.1.el6.x86_64 cifs-utils: cifs-utils-4.8.1-19.el6.x86_64 How reproducible: 100% Steps to Reproduce: 1. Attempt to mount a CIFS DFS share with any security mode. # mount -o sec=ntlmssp,username=user,domain=domain //kasane.local/neet /neet Actual results: Error 95 [root@nayuki ~]# mount.cifs -o sec=ntlm,username=teto,domain=kasane //kasane.local/neet /neet mount error(95): Operation not supported Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) Expected results: Success (no error) Additional info: Node can be mounted directly, or DFS share can be mounted without sec option: [root@nayuki ~]# mount.cifs -o username=teto,domain=kasane '//kasane.local/neet/triplebaka' /neet/ [root@nayuki ~]# grep cifs /proc/mounts //kasane.local/neet/triplebaka /neet cifs rw,relatime,sec=ntlm,cache=loose,unc=\134\134neru\134triplebaka,username=teto,domain=kasane,uid=0,noforceuid,gid=0,noforcegid,addr=192.168.122.101,file_mode=0755,dir_mode=0755,nounix,serverino,rsize=61440,wsize=65536,actimeo=1 0 0 [root@nayuki ~]# Direct to node, bypassing DFS: [root@nayuki ~]# mount.cifs -o sec=ntlmssp,username=teto,domain=kasane '//neru/triplebaka' /neet/ [root@nayuki ~]# ls /neet/ install.log [root@nayuki ~]# grep cifs /proc/mounts //neru/triplebaka/ /neet cifs rw,relatime,sec=ntlmssp,cache=loose,unc=\134\134neru\134triplebaka,username=teto,domain=kasane,uid=0,noforceuid,gid=0,noforcegid,addr=192.168.122.101,file_mode=0755,dir_mode=0755,nounix,serverino,rsize=61440,wsize=65536,actimeo=1 0 0 A network trace shows that nothing occurs after: 53 8.243534 192.168.122.100 192.168.122.16 SMB 148 Negotiate Protocol Request 54 8.244503 192.168.122.16 192.168.122.100 SMB 275 Negotiate Protocol Response
Also tested this on 2.6.32-279.el6.x86_64 with cifs-utils-4.4-5.el6.x86_64: [root@nayuki ~]# mount.cifs -o sec=ntlmssp,username=administrator,domain=kasane '//kasane.local/neet/triplebaka' /neet/ mount error(95): Operation not supported Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) [root@nayuki ~]# rpm -q cifs-utils cifs-utils-4.4-5.el6.x86_64 [root@nayuki ~]# uname -r 2.6.32-279.el6.x86_64 root@nayuki ~]# mount.cifs -o username=administrator,domain=kasane '//kasane.local/neet/triplebaka' /neet/ [root@nayuki ~]# echo success!
I suspect this could be relevant to how packet signing is handled, as these messages appear in the system logs: Mar 2 16:02:13 nayuki kernel: CIFS VFS: signing required but server lacks support Mar 2 16:02:13 nayuki kernel: CIFS VFS: cifs_mount failed w/return code = -95 Mar 2 16:02:19 nayuki kernel: CIFS VFS: Server requires packet signing to be enabled in /proc/fs/cifs/SecurityFlags. Mar 2 16:02:19 nayuki kernel: CIFS VFS: cifs_mount failed w/return code = -95 These are for the following mount attempts: [root@nayuki ~]# mount.cifs -o sec=ntlmi,username=teto,domain=kasane '//kasane.local/neet/triplebaka' /neet/ mount error(95): Operation not supported Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) [root@nayuki ~]# mount.cifs -o sec=ntlm,username=teto,domain=kasane '//kasane.local/neet/triplebaka' /neet/ mount error(95): Operation not supported Refer to the mount.cifs(8) manual page (e.g. man mount.cifs) In this case, the server is Windows 2008 R2. Please let me know if any other data would be helpful. [root@nayuki ~]# smbclient -L //haku.kasane.local -U kasane/teto Enter kasane/teto's password: Domain=[KASANE] OS=[Windows Server 2008 R2 Standard 7600] Server=[Windows Server 2008 R2 Standard 6.1] Sharename Type Comment --------- ---- ------- ADMIN$ Disk Remote Admin C$ Disk Default share IPC$ IPC Remote IPC neet Disk NETLOGON Disk Logon server share orz Disk SYSVOL Disk Logon server share session request to HAKU.KASANE.LOCA failed (Called name not present) Domain=[KASANE] OS=[Windows Server 2008 R2 Standard 7600] Server=[Windows Server 2008 R2 Standard 6.1] Server Comment --------- ------- Workgroup Master --------- -------
Patch(es) available on kernel-2.6.32-582.el6
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHSA-2016-0855.html