Hi, could anyone please tell me whether the combination mount.cifs+Kerberos+SMB2/SMB3 is supposed to work? >From what I see, Linux doesn't even consider Kerberos when speaking SMB2 or SMB3. After the Negotiate Protocol Response from the server, the client sends an ACK and then follows up with an NTLMSSP_NEGOTIATE. There is no Kerberos at all in the conversation. At least not that Wireshark finds. These are the commands that fail with mount error(13): Permission denied mount.cifs //ws.mydomain.com/ydrive /mnt/y -omultiuser,sec=krb5,noexec,nosuid,vers=3.0 and kinit n123456 mount -t cifs -overs=3.0,sec=krb5 //ws.mydomain.com/homedrive/staff/user3/N123456 /mnt/x -o uid=10123456,gid=10123456 Particularities: - Cifs.upcall is set to run with the option '-t' (because Kerberized NFS4 breaks without it). Removing the option doesn't help. - These are DFS shares (if that is a correct term) with several referrals. (Simpler shares cannot be accessed either.) - The Kerberos server is Microsoft Server 2012 AD. Msktutil (not winbind) was used to join the host to the AD domain. - /proc/fs/cifs/SecurityFlags is set to 0x8009. (The default 0x85 doesn't work either.) Things that do help: - Use vers=1.0. - Leave out the sec=krb5. (Get asked for a password, NTLM* works.) So this is the status: SMB1 SMB2 SMB3 ntlm* work work work krb5* work fail fail Versions: Kernel 3.17.0 Mount.cifs 6.4 I'll happily provide wireshark captures or try other situations. FWIW, this is what the kernel ringbuffer says (after the first mount command above): [ 75.119448] /home/apw/COD/linux/fs/cifs/cifsfs.c: Devname: //ws.mydomain.com/ydrive flags: 0 [ 75.119465] /home/apw/COD/linux/fs/cifs/connect.c: Username: root [ 75.137511] /home/apw/COD/linux/fs/cifs/connect.c: file mode: 0x1ed dir mode: 0x1ed [ 75.137541] /home/apw/COD/linux/fs/cifs/connect.c: CIFS VFS: in cifs_mount as Xid: 0 with uid: 0 [ 75.137543] /home/apw/COD/linux/fs/cifs/connect.c: UNC: \\ws.mydomain.com\ydrive [ 75.137548] /home/apw/COD/linux/fs/cifs/connect.c: Socket created [ 75.137549] /home/apw/COD/linux/fs/cifs/connect.c: sndbuf 16384 rcvbuf 87380 rcvtimeo 0x6d6 [ 75.137964] /home/apw/COD/linux/fs/cifs/connect.c: Demultiplex PID: 1823 [ 75.137966] /home/apw/COD/linux/fs/cifs/fscache.c: cifs_fscache_get_client_cookie: (0xffff8800c3060000/0xffff8800c3f0f000) [ 75.137969] /home/apw/COD/linux/fs/cifs/connect.c: CIFS VFS: in cifs_get_smb_ses as Xid: 1 with uid: 0 [ 75.137970] /home/apw/COD/linux/fs/cifs/connect.c: Existing smb sess not found [ 75.137972] /home/apw/COD/linux/fs/cifs/smb2pdu.c: Negotiate protocol [ 75.137977] /home/apw/COD/linux/fs/cifs/transport.c: Sending smb: smb_len=102 [ 75.138745] /home/apw/COD/linux/fs/cifs/connect.c: RFC1002 header 0xf8 [ 75.138748] /home/apw/COD/linux/fs/cifs/smb2misc.c: smb2_check_message length: 0xfc, smb_buf_length: 0xf8 [ 75.138749] /home/apw/COD/linux/fs/cifs/smb2misc.c: SMB2 data length 120 offset 128 [ 75.138750] /home/apw/COD/linux/fs/cifs/smb2misc.c: SMB2 len 252 [ 75.138780] /home/apw/COD/linux/fs/cifs/transport.c: cifs_sync_mid_result: cmd=0 mid=0 state=4 [ 75.138782] /home/apw/COD/linux/fs/cifs/misc.c: Null buffer passed to cifs_small_buf_release [ 75.138784] /home/apw/COD/linux/fs/cifs/smb2pdu.c: mode 0x3 [ 75.138785] /home/apw/COD/linux/fs/cifs/smb2pdu.c: negotiated smb3.0 dialect [ 75.138786] /home/apw/COD/linux/fs/cifs/connect.c: Security Mode: 0x3 Capabilities: 0x300007 TimeAdjust: 0 [ 75.138787] /home/apw/COD/linux/fs/cifs/smb2pdu.c: Session Setup [ 75.138789] /home/apw/COD/linux/fs/cifs/transport.c: Sending smb: smb_len=120 [ 75.139346] /home/apw/COD/linux/fs/cifs/connect.c: RFC1002 header 0x142 [ 75.139350] /home/apw/COD/linux/fs/cifs/smb2misc.c: smb2_check_message length: 0x146, smb_buf_length: 0x142 [ 75.139351] /home/apw/COD/linux/fs/cifs/smb2misc.c: SMB2 data length 250 offset 72 [ 75.139352] /home/apw/COD/linux/fs/cifs/smb2misc.c: SMB2 len 326 [ 75.139381] /home/apw/COD/linux/fs/cifs/transport.c: cifs_sync_mid_result: cmd=1 mid=1 state=4 [ 75.139384] /home/apw/COD/linux/fs/cifs/smb2maperror.c: Mapping SMB2 status code -1073741802 to POSIX err -5 [ 75.139385] /home/apw/COD/linux/fs/cifs/misc.c: Null buffer passed to cifs_small_buf_release [ 75.156277] /home/apw/COD/linux/fs/cifs/transport.c: Sending smb: smb_len=416 [ 75.157777] /home/apw/COD/linux/fs/cifs/connect.c: RFC1002 header 0x49 [ 75.157781] /home/apw/COD/linux/fs/cifs/smb2misc.c: smb2_check_message length: 0x4d, smb_buf_length: 0x49 [ 75.157782] /home/apw/COD/linux/fs/cifs/smb2misc.c: SMB2 data length 0 offset 0 [ 75.157783] /home/apw/COD/linux/fs/cifs/smb2misc.c: SMB2 len 77 [ 75.157803] /home/apw/COD/linux/fs/cifs/transport.c: cifs_sync_mid_result: cmd=1 mid=2 state=4 [ 75.157806] Status code returned 0xc000006d STATUS_LOGON_FAILURE [ 75.157810] /home/apw/COD/linux/fs/cifs/smb2maperror.c: Mapping SMB2 status code -1073741715 to POSIX err -13 [ 75.157811] /home/apw/COD/linux/fs/cifs/misc.c: Null buffer passed to cifs_small_buf_release [ 75.157812] CIFS VFS: Send error in SessSetup = -13 [ 75.157815] /home/apw/COD/linux/fs/cifs/connect.c: CIFS VFS: leaving cifs_get_smb_ses (xid = 1) rc = -13 [ 75.157817] /home/apw/COD/linux/fs/cifs/fscache.c: cifs_fscache_release_client_cookie: (0xffff8800c3060000/0xffff8800c3f0f000) [ 75.157864] /home/apw/COD/linux/fs/cifs/connect.c: CIFS VFS: leaving cifs_mount (xid = 0) rc = -13 [ 75.157866] CIFS VFS: cifs_mount failed w/return code = -13 Many thanks! Jurjen Bokma -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html