It's possible that when we go to decode the string area in the
SESSION_SETUP response, that bytes_remaining will be 0. Decrementing it at
that point will mean that it can go "negative" and wrap. Check for a
bytes_remaining value of 0, and don't try to decode the string area if
that's the case.

Cc: stable@kernel.org
Reported-and-Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

The buffer length checks in this function depend on this value being a
signed data type, but 690c522f converted it to an unsigned type.

Also, eliminate a problem with the null termination check in the same
function. cifs_strndup_from_ucs handles that situation correctly
already, and the existing check could potentially lead to a buffer
overrun since it increments bleft without checking to see whether it
falls off the end of the buffer.

Cc: stable@kernel.org
Reported-and-Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

make modules C=2 M=fs/cifs CF=-D__CHECK_ENDIAN__

Found for example:

 CHECK   fs/cifs/cifssmb.c
fs/cifs/cifssmb.c:728:22: warning: incorrect type in assignment (different base types)
fs/cifs/cifssmb.c:728:22:    expected unsigned short [unsigned] [usertype] Tid
fs/cifs/cifssmb.c:728:22:    got restricted __le16 [usertype] <noident>
fs/cifs/cifssmb.c:1883:45: warning: incorrect type in assignment (different base types)
fs/cifs/cifssmb.c:1883:45:    expected long long [signed] [usertype] fl_start
fs/cifs/cifssmb.c:1883:45:    got restricted __le64 [usertype] start
fs/cifs/cifssmb.c:1884:54: warning: restricted __le64 degrades to integer
fs/cifs/cifssmb.c:1885:58: warning: restricted __le64 degrades to integer
fs/cifs/cifssmb.c:1886:43: warning: incorrect type in assignment (different base types)
fs/cifs/cifssmb.c:1886:43:    expected unsigned int [unsigned] fl_pid
fs/cifs/cifssmb.c:1886:43:    got restricted __le32 [usertype] pid

In checking new smb2 code for missing endian conversions, I noticed
some endian errors had crept in over the last few releases into the
cifs code (symlink, ntlmssp, posix lock, and also a less problematic warning
in fscache).  A followon patch will address a few smb2 endian
problems.
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

We artificially limited the user name to 32 bytes, but modern servers handle
larger.  Set the maximum length to a reasonable 256, and make the user name
string dynamically allocated rather than a fixed size in session structure.
Also clean up old checkpatch warning.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

LANMAN response length was changed to 16 bytes instead of 24 bytes.
Revert it back to 24 bytes.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
CC: stable@kernel.org
Signed-off-by: NSteve French <sfrench@us.ibm.com>

It's possible that when we access the ByteCount that the alignment
will be off. Most CPUs deal with that transparently, but there's
usually some performance impact. Some CPUs raise an exception on
unaligned accesses.

Fix this by accessing the byte count using the get_unaligned and
put_unaligned inlined functions. While we're at it, fix the types
of some of the variables that end up getting returns from these
functions.
Acked-by: NPavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Since we don't time out individual requests anymore, remove the code
that we used to use for setting timeouts on different requests.
Reviewed-by: NPavel Shilovsky <piastryyy@gmail.com>
Reviewed-by: NSuresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

I see no real need to leave these sorts of options under an
EXPERIMENTAL ifdef. Since you need a mount option to turn this code
on, that only blows out the testing matrix.

local_leases has been under the EXPERIMENTAL tag for some time, but
it's only the mount option that's under this label. Move it out
from under this tag.

The NTLMSSP code is also under EXPERIMENTAL, but it needs a mount
option to turn it on, and in the future any distro will reasonably
want this enabled. Go ahead and move it out from under the
EXPERIMENTAL tag.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NSuresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Indicate to the server a capability of NTLM2 session security (NTLM2 Key)
during ntlmssp protocol exchange in one of the bits of the flags field.
If server supports this capability, send NTLM2 key even if signing is not
required on the server.

If the server requires signing, the session keys exchanged for NTLMv2
and NTLM2 session security in auth packet of the nlmssp exchange are same.

Send the same flags in authenticate message (type 3) that client sent in
negotiate message (type 1).

Remove function setup_ntlmssp_neg_req

Make sure ntlmssp negotiate and authenticate messages are zero'ed
before they are built.
Reported-and-Tested-by: NRobbert Kouprie <robbert@exx.nl>
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Removed following fields from smb session structure
 cryptkey, ntlmv2_hash, tilen, tiblob
and ntlmssp_auth structure is allocated dynamically only if the auth mech
in NTLMSSP.

response field within a session_key structure is used to initially store the
target info (either plucked from type 2 challenge packet in case of NTLMSSP
or fabricated in case of NTLMv2 without extended security) and then to store
Message Authentication Key (mak) (session key + client response).

Server challenge or cryptkey needed during a NTLMSSP authentication
is now part of ntlmssp_auth structure which gets allocated and freed
once authenticaiton process is done.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Need to have cryptkey or server challenge in smb connection
(struct TCP_Server_Info) for ntlm and ntlmv2 auth types for which
cryptkey (Encryption Key) is supplied just once in Negotiate Protocol
response during an smb connection setup for all the smb sessions over
that smb connection.

For ntlmssp, cryptkey or server challenge is provided for every
smb session in type 2 packet of ntlmssp negotiation, the cryptkey
provided during Negotiation Protocol response before smb connection
does not count.

Rename cryptKey to cryptkey and related changes.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Minor cleanup - Fix spelling mistake, make meaningful (goto) label

In function setup_ntlmv2_rsp(), do not return 0 and leak memory,
let the tiblob get freed.

For function find_domain_name(), pass already available nls table pointer
instead of loading and unloading the table again in this function.

For ntlmv2, the case sensitive password length is the length of the
response, so subtract session key length (16 bytes) from the .len.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Mark dependency on crypto modules in Kconfig.

Defining per structures sdesc and cifs_secmech which are used to store
crypto hash functions and contexts.  They are stored per smb connection
and used for all auth mechs to genereate hash values and signatures.

Allocate crypto hashing functions, security descriptiors, and respective
contexts when a smb/tcp connection is established.
Release them when a tcp/smb connection is taken down.

md5 and hmac-md5 are two crypto hashing functions that are used
throught the life of an smb/tcp connection by various functions that
calcualte signagure and ntlmv2 hash, HMAC etc.

structure ntlmssp_auth is defined as per smb connection.

ntlmssp_auth holds ciphertext which is genereated by rc4/arc4 encryption of
secondary key, a nonce using ntlmv2 session key and sent in the session key
field of the type 3 message sent by the client during ntlmssp
negotiation/exchange

A key is exchanged with the server if client indicates so in flags in
type 1 messsage and server agrees in flag in type 2 message of ntlmssp
negotiation.  If both client and agree, a key sent by client in
type 3 message of ntlmssp negotiation in the session key field.
The key is a ciphertext generated off of secondary key, a nonce, using
ntlmv2 hash via rc4/arc4.

Signing works for ntlmssp in this patch. The sequence number within
the server structure needs to be zero until session is established
i.e. till type 3 packet of ntlmssp exchange of a to be very first
smb session on that smb connection is sent.
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Start calculating auth response within a session.  Move/Add pertinet
data structures like session key, server challenge and ntlmv2_hash in
a session structure.  We should do the calculations within a session
before copying session key and response over to server data
structures because a session setup can fail.

Only after a very first smb session succeeds, it copy/make its
session key, session key of smb connection.  This key stays with
the smb connection throughout its life.
sequence_number within server is set to 0x2.

The authentication Message Authentication Key (mak) which consists
of session key followed by client response within structure session_key
is now dynamic.  Every authentication type allocates the key + response
sized memory within its session structure and later either assigns or
frees it once the client response is sent and if session's session key
becomes connetion's session key.

ntlm/ntlmi authentication functions are rearranged.  A function
named setup_ntlm_resp(), similar to setup_ntlmv2_resp(), replaces
function cifs_calculate_session_key().

size of CIFS_SESS_KEY_SIZE is changed to 16, to reflect the byte size
of the key it holds.
Reviewed-by: NJeff Layton <jlayton@samba.org>
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

cifs_tcp_ses_lock is a rwlock with protects the cifs_tcp_ses_list,
server->smb_ses_list and the ses->tcon_list. It also protects a few
ref counters in server, ses and tcon. In most cases the critical section
doesn't seem to be large, in a few cases where it is slightly large, there
seem to be really no benefit from concurrent access. I briefly considered RCU
mechanism but it appears to me that there is no real need.

Replace it with a spinlock and get rid of the last rwlock in the cifs code.
Signed-off-by: NSuresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

- Eliminate double declaration of variable blob_len
- Modify function build_ntlmssp_auth_blob to return error code
  as well as length of the blob.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: NJeff Layton <jlayton@samba.org>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Start calculation auth response within a session.  Move/Add pertinet
data structures like session key, server challenge and ntlmv2_hash in
a session structure.  We should do the calculations within a session
before copying session key and response over to server data
structures because a session setup can fail.

Only after a very first smb session succeeds, it copies/makes its
session key, session key of smb connection.  This key stays with
the smb connection throughout its life.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

ntlm authentication and signing - Correct response length for ntlmv2 authentication without extended security

Fix incorrect calculation of case sensitive response length in the
ntlmv2 (without extended security) response.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Attribue Value (AV) pairs or Target Info (TI) pairs are part of
ntlmv2 authentication.
Structure ntlmv2_resp had only definition for two av pairs.
So removed it, and now allocation of av pairs is dynamic.
For servers like Windows 7/2008, av pairs sent by server in
challege packet (type 2 in the ntlmssp exchange/negotiation) can
vary.

Server sends them during ntlmssp negotiation. So when ntlmssp is used
as an authentication mechanism, type 2 challenge packet from server
has this information.  Pluck it and use the entire blob for
authenticaiton purpose.  If user has not specified, extract
(netbios) domain name from the av pairs which is used to calculate
ntlmv2 hash.  Servers like Windows 7 are particular about the AV pair
blob.

Servers like Windows 2003, are not very strict about the contents
of av pair blob used during ntlmv2 authentication.
So when security mechanism such as ntlmv2 is used (not ntlmv2 in ntlmssp),
there is no negotiation and so genereate a minimal blob that gets
used in ntlmv2 authentication as well as gets sent.

Fields tilen and tilbob are session specific.  AV pair values are defined.

To calculate ntlmv2 response we need ti/av pair blob.

For sec mech like ntlmssp, the blob is plucked from type 2 response from
the server.  From this blob, netbios name of the domain is retrieved,
if user has not already provided, to be included in the Target String
as part of ntlmv2 hash calculations.

For sec mech like ntlmv2, create a minimal, two av pair blob.

The allocated blob is freed in case of error.  In case there is no error,
this blob is used in calculating ntlmv2 response (in CalcNTLMv2_response)
and is also copied on the response to the server, and then freed.

The type 3 ntlmssp response is prepared on a buffer,
5 * sizeof of struct _AUTHENTICATE_MESSAGE, an empirical value large
enough to hold _AUTHENTICATE_MESSAGE plus a blob with max possible
10 values as part of ntlmv2 response and lmv2 keys and domain, user,
workstation  names etc.

Also, kerberos gets selected as a default mechanism if server supports it,
over the other security mechanisms.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Change name of variable mac_key to session key.
The reason mac_key was changed to session key is, this structure does not
hold message authentication code, it holds the session key (for ntlmv2,
ntlmv1 etc.).  mac is generated as a signature in cifs_calc* functions.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

This reverts commit 9fbc5908.

The change to kernel crypto and fixes to ntlvm2 and ntlmssp
series, introduced a regression.  Deferring this patch series
to 2.6.37 after Shirish fixes it.
Signed-off-by: NSteve French <sfrench@us.ibm.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
CC: Shirish Pargaonkar <shirishp@us.ibm.com>

This reverts commit 3ec6bbcd.

    The change to kernel crypto and fixes to ntlvm2 and ntlmssp
    series, introduced a regression.  Deferring this patch series
    to 2.6.37 after Shirish fixes it.
Signed-off-by: NSteve French <sfrench@us.ibm.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
CC: Shirish Pargaonkar <shirishp@us.ibm.com>

The change to kernel crypto and fixes to ntlvm2 and ntlmssp
series, introduced a regression.  Deferring this patch series
to 2.6.37 after Shirish fixes it.

This reverts commit c89e5198.
Signed-off-by: NSteve French <sfrench@us.ibm.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
CC: Shirish Pargaonkar <shirishp@us.ibm.com>

CC: Shirish Pargaonkar <shirishp@us.ibm.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Make ntlmv2 as an authentication mechanism within ntlmssp
instead of ntlmv1.
Parse type 2 response in ntlmssp negotiation to pluck
AV pairs and use them to calculate ntlmv2 response token.
Also, assign domain name from the sever response in type 2
packet of ntlmssp and use that (netbios) domain name in
calculation of response.

Enable cifs/smb signing using rc4 and md5.

Changed name of the structure mac_key to session_key to reflect
the type of key it holds.

Use kernel crypto_shash_* APIs instead of the equivalent cifs functions.
Signed-off-by: NShirish Pargaonkar <shirishpargaonkar@gmail.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

This bug appears to be the result of a cut-and-paste mistake from the
NTLMv1 code. The function to generate the MAC key was commented out, but
not the conditional above it. The conditional then ended up causing the
session setup key not to be copied to the buffer unless this was the
first session on the socket, and that made all but the first NTLMv2
session setup fail.

Fix this by removing the conditional and all of the commented clutter
that made it difficult to see.

Cc: Stable <stable@kernel.org>
Reported-by: NGunther Deschner <gdeschne@redhat.com>
Signed-off-by: NJeff Layton <jlayton@redhat.com>

...rather than the secType. This allows us to get rid of the MSKerberos
securityEnum. The client just makes a decision at upcall time.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

We can use the is_first_ses_reconnect() function to determine this.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Neaten cERROR and cFYI macros, reduce text space
~2.5K

Convert '__FILE__ ": " fmt' to '"%s: " fmt', __FILE__' to save text space
Surround macros with do {} while
Add parentheses to macros
Make statement expression macro from macro with assign
Remove now unnecessary parentheses from cFYI and cERROR uses

defconfig with CIFS support old
$ size fs/cifs/built-in.o
   text	   data	    bss	    dec	    hex	filename
 156012	   1760	    148	 157920	  268e0	fs/cifs/built-in.o

defconfig with CIFS support old
$ size fs/cifs/built-in.o
   text	   data	    bss	    dec	    hex	filename
 153508	   1760	    148	 155416	  25f18	fs/cifs/built-in.o

allyesconfig old:
$ size fs/cifs/built-in.o
   text	   data	    bss	    dec	    hex	filename
 309138	   3864	  74824	 387826	  5eaf2	fs/cifs/built-in.o

allyesconfig new
$ size fs/cifs/built-in.o
   text	   data	    bss	    dec	    hex	filename
 305655	   3864	  74824	 384343	  5dd57	fs/cifs/built-in.o
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Fix length check reported by D. Binderman (see below)

d binderman <dcb314@hotmail.com> wrote:
>
> I just ran the sourceforge tool cppcheck over the source code of the
> new Linux kernel 2.6.33-rc6
>
> It said
>
> [./cifs/sess.c:250]: (error) Buffer access out-of-bounds

May turn out to be harmless, but best to be safe. Note max
username length is defined to 32 due to Linux (Windows
maximum is 20).
Signed-off-by: NSteve French <sfrench@us.ibm.com>

Also removes obsolete distinction between rawntlmssp and ntlmssp (in asn/SPNEGO)
since as jra noted we can always send raw ntlmssp in session setup now.

remove check for experimental runtime flag (/proc/fs/cifs/Experimental) in
ntlmssp path.
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

We were not setting the SMB uid in NTLMSSP authenticate
request which could lead to INVALID_PARAMETER error
on 2nd session setup.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

The NTLMSSP code was removed from fs/cifs/connect.c and merged
(75% smaller, cleaner) into fs/cifs/sess.c

As with the old code it requires that cifs be built with
CONFIG_CIFS_EXPERIMENTAL, the /proc/fs/cifs/Experimental flag
must be set to 2, and mount must turn on extended security
(e.g. with sec=krb5).

Although NTLMSSP encapsulated in SPNEGO is not enabled yet,
"raw" ntlmssp is common and useful in some cases since it
offers more complete security negotiation, and is the
default way of negotiating security for many Windows systems.
SPNEGO encapsulated NTLMSSP will be able to reuse the same
code.
Signed-off-by: NSteve French <sfrench@us.ibm.com>

When multiply mounting from the same client to the same server, with
different userids, we create a vcnum which should be unique if
possible (this is not the same as the smb uid, which is the handle
to the security context).  We were not endian converting additional
(beyond the first which is zero) vcnum properly.

CC: Stable <stable@kernel.org>
Acked-by: NShirish Pargaonkar <shirishp@us.ibm.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

In most cases, cifs_strndup is converting from Unicode (UCS2 / UTF-32) to
the configured local code page for the Linux mount (usually UTF8), so
Jeff suggested that to make it more clear that cifs_strndup is doing
a conversion not just memory allocation and copy, rename the function
to including "from_ucs" (ie Unicode)
Signed-off-by: NSteve French <sfrench@us.ibm.com>

...and change decode_unicode_ssetup to be a void function. It never
returns an actual error anyway.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NSuresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

...to make it easier to find problems in this area in the future.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Signed-off-by: NSteve French <sfrench@us.ibm.com>

The handling of unicode string area alignment is wrong.
decode_unicode_ssetup improperly assumes that it will always be preceded
by a pad byte. This isn't the case if the string area is already
word-aligned.

This problem, combined with the bad buffer sizing for the serverDomain
string can cause memory corruption. The bad alignment can make it so
that the alignment of the characters is off. This can make them
translate to characters that are greater than 2 bytes each. If this
happens we can overflow the allocation.

Fix this by fixing the alignment in CIFS_SessSetup instead so we can
verify it against the head of the response. Also, clean up the
workaround for improperly terminated strings by checking for a
odd-length unicode buffers and then forcibly terminating them.

Finally, resize the buffer for serverDomain. Now that we've fixed
the alignment, it's probably fine, but a malicious server could
overflow it.

A better solution for handling these strings is still needed, but
this should be a suitable bandaid.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
CC: Stable <stable@vger.kernel.org>
Signed-off-by: NSteve French <sfrench@us.ibm.com>