[SRU][Xenial][Zesty][Artful][azure][PATCH 1/1] CIFS: Fix maximum SMB2 header size

[Joseph Salisbury]

From: Pavel Shilovsky <pshilov at microsoft.com>

BugLink: http://bugs.launchpad.net/bugs/1713884

Currently the maximum size of SMB2/3 header is set incorrectly which
leads to hanging of directory listing operations on encrypted SMB3
connections. Fix this by setting the maximum size to 170 bytes that
is calculated as RFC1002 length field size (4) + transform header
size (52) + SMB2 header size (64) + create response size (56).

Cc: <stable at vger.kernel.org>
Signed-off-by: Pavel Shilovsky <pshilov at microsoft.com>
Signed-off-by: Steve French <smfrench at gmail.com>
Acked-by: Sachin Prabhu <sprabhu at redhat.com>
(cherry picked from commit 9e37b1784f2be9397a903307574ee565bbadfd75)
Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
---
 fs/cifs/smb2pdu.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index 18700fd..2826882 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -84,8 +84,8 @@
 
 #define NUMBER_OF_SMB2_COMMANDS	0x0013
 
-/* BB FIXME - analyze following length BB */
-#define MAX_SMB2_HDR_SIZE 0x78 /* 4 len + 64 hdr + (2*24 wct) + 2 bct + 2 pad */
+/* 4 len + 52 transform hdr + 64 hdr + 56 create rsp */
+#define MAX_SMB2_HDR_SIZE 0x00b0
 
 #define SMB2_PROTO_NUMBER cpu_to_le32(0x424d53fe)
 #define SMB2_TRANSFORM_PROTO_NUM cpu_to_le32(0x424d53fd)
-- 
2.7.4