do not treat non-symlink reparse points as valid symlinks

Windows 8 and later can create NFS symlinks (within reparse points)
which we were assuming were normal NTFS symlinks and thus reporting
corrupt paths for.  Add check for reparse points to make sure that
they really are normal symlinks before we try to parse the pathname.

We also should not be parsing other types of reparse points (DFS
junctions etc) as if they were a  symlink so return EOPNOTSUPP
on those.  Also fix endian errors (we were not parsing symlink
lengths as little endian).

This fixes commit d244bf2dfbebfded05f494ffd53659fa7b1e32c1
which implemented follow link for non-Unix CIFS mounts

CC: Stable <stable@kernel.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
cifs: Avoid umount hangs with smb2 when server is unresponsive

Do not send SMB2 Logoff command when reconnecting, the way smb1
code base works.

Also, no need to wait for a credit for an echo command when one is already
in flight.

Without these changes, umount command hangs if the server is unresponsive
e.g. hibernating.

Signed-off-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@us.ibm.com>
cifs: Fix inability to write files >2GB to SMB2/3 shares

When connecting to SMB2/3 shares, maximum file size is set to non-LFS maximum in superblock. This is due to cap_large_files bit being different for SMB1 and SMB2/3 (where it is just an internal flag that is not negotiated and the SMB1 one corresponds to multichannel capability, so maybe LFS works correctly if server sends 0x08 flag) while capabilities are checked always for the SMB1 bit in cifs_read_super().

The patch fixes this by checking for the correct bit according to the protocol version.

CC: Stable <stable@kernel.org>
Signed-off-by: Jan Klos <honza.klos@gmail.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
cifs: Allow LANMAN auth method for servers supporting unencapsulated authentication methods

This allows users to use LANMAN authentication on servers which support
unencapsulated authentication.

The patch fixes a regression where users using plaintext authentication
were no longer able to do so because of changed bought in by patch
3f618223dc0bdcbc8d510350e78ee2195ff93768

https://bugzilla.redhat.com/show_bug.cgi?id=1011621

Reported-by: Panos Kavalagios <Panagiotis.Kavalagios@eurodyn.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>
cifs: ntstatus_to_dos_map[] is not terminated

Functions that walk the ntstatus_to_dos_map[] array could
run off the end. For example, ntstatus_to_dos() loops
while ntstatus_to_dos_map[].ntstatus is not 0. Granted,
this is mostly theoretical, but could be used as a DOS attack
if the error code in the SMB header is bogus.

[Might consider adding to stable, as this patch is low risk - Steve]

Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Steve French <smfrench@gmail.com>
Merge branch 'for-linus' of git://git.samba.org/sfrench/cifs-2.6

Pull CIFS fixes from Steve French:
 "Five small cifs fixes (includes fixes for: unmount hang, 2 security
  related, symlink, large file writes)"

* 'for-linus' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: ntstatus_to_dos_map[] is not terminated
  cifs: Allow LANMAN auth method for servers supporting unencapsulated authentication methods
  cifs: Fix inability to write files >2GB to SMB2/3 shares
  cifs: Avoid umount hangs with smb2 when server is unresponsive
  do not treat non-symlink reparse points as valid symlinks