[CIFS] Warn if SMB3 encryption required by server

We do not support SMB3 encryption yet, warn if server responds
that SMB3 encryption is mandatory.

Signed-off-by: Steve French <smfrench@gmail.com>

2 files changed, 20 insertions, 0 deletions

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index ca7f307ad97a..d65270c290a1 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -630,6 +630,8 @@ ssetup_ntlmssp_authenticate:
                 goto ssetup_exit;
 
         ses->session_flags = le16_to_cpu(rsp->SessionFlags);
+        if (ses->session_flags & SMB2_SESSION_FLAG_ENCRYPT_DATA)
+                cifs_dbg(VFS, "SMB3 encryption not supported yet\n");
 ssetup_exit:
         free_rsp_buf(resp_buftype, rsp);
 
diff --git a/fs/cifs/smb2pdu.h b/fs/cifs/smb2pdu.h
index b50a129572cd..f88320bbb477 100644
--- a/fs/cifs/smb2pdu.h
+++ b/fs/cifs/smb2pdu.h
@@ -122,6 +122,23 @@ struct smb2_pdu {
         __le16 StructureSize2; /* size of wct area (varies, request specific) */
 } __packed;
 
+struct smb2_transform_hdr {
+        __be32 smb2_buf_length; /* big endian on wire */
+                                /* length is only two or three bytes - with
+                                 one or two byte type preceding it that MBZ */
+        __u8   ProtocolId[4];   /* 0xFD 'S' 'M' 'B' */
+        __u8   Signature[16];
+        __u8   Nonce[11];
+        __u8   Reserved[5];
+        __le32 OriginalMessageSize;
+        __u16  Reserved1;
+        __le16 EncryptionAlgorithm;
+        __u64  SessionId;
+} __packed;
+
+/* Encryption Algorithms */
+#define SMB2_ENCRYPTION_AES128_CCM      __constant_cpu_to_le16(0x0001)
+
 /*
  *      SMB2 flag definitions
  */
@@ -237,6 +254,7 @@ struct smb2_sess_setup_req {
 /* Currently defined SessionFlags */
 #define SMB2_SESSION_FLAG_IS_GUEST      0x0001
 #define SMB2_SESSION_FLAG_IS_NULL       0x0002
+#define SMB2_SESSION_FLAG_ENCRYPT_DATA  0x0004
 struct smb2_sess_setup_rsp {
         struct smb2_hdr hdr;
         __le16 StructureSize; /* Must be 9 */