smb3: send NTLMSSP version information

For improved debugging it can be helpful to send version information
as other clients do during NTLMSSP negotiation. See protocol document
MS-NLMP section 2.2.1.1

Set the major and minor versions based on the kernel version, and the
BuildNumber based on the internal cifs.ko module version number,
and following the recommendation in the protocol documentation
(MS-NLMP section 2.2.10) we set the NTLMRevisionCurrent field to 15.

Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
index 15373a377a36..dc3b16d1be09 100644
--- a/fs/cifs/sess.c
+++ b/fs/cifs/sess.c
@@ -17,6 +17,8 @@
 #include "nterr.h"
 #include <linux/utsname.h>
 #include <linux/slab.h>
+#include <linux/version.h>
+#include "cifsfs.h"
 #include "cifs_spnego.h"
 #include "smb2proto.h"
 #include "fs_context.h"
@@ -809,6 +811,74 @@ setup_ntlm_neg_ret:
 	return rc;
 }
 
+/*
+ * Build ntlmssp blob with additional fields, such as version,
+ * supported by modern servers. For safety limit to SMB3 or later
+ * See notes in MS-NLMP Section 2.2.2.1 e.g.
+ */
+int build_ntlmssp_smb3_negotiate_blob(unsigned char **pbuffer,
+				 u16 *buflen,
+				 struct cifs_ses *ses,
+				 struct TCP_Server_Info *server,
+				 const struct nls_table *nls_cp)
+{
+	int rc = 0;
+	struct negotiate_message *sec_blob;
+	__u32 flags;
+	unsigned char *tmp;
+	int len;
+
+	len = size_of_ntlmssp_blob(ses, sizeof(struct negotiate_message));
+	*pbuffer = kmalloc(len, GFP_KERNEL);
+	if (!*pbuffer) {
+		rc = -ENOMEM;
+		cifs_dbg(VFS, "Error %d during NTLMSSP allocation\n", rc);
+		*buflen = 0;
+		goto setup_ntlm_smb3_neg_ret;
+	}
+	sec_blob = (struct negotiate_message *)*pbuffer;
+
+	memset(*pbuffer, 0, sizeof(struct negotiate_message));
+	memcpy(sec_blob->Signature, NTLMSSP_SIGNATURE, 8);
+	sec_blob->MessageType = NtLmNegotiate;
+
+	/* BB is NTLMV2 session security format easier to use here? */
+	flags = NTLMSSP_NEGOTIATE_56 |	NTLMSSP_REQUEST_TARGET |
+		NTLMSSP_NEGOTIATE_128 | NTLMSSP_NEGOTIATE_UNICODE |
+		NTLMSSP_NEGOTIATE_NTLM | NTLMSSP_NEGOTIATE_EXTENDED_SEC |
+		NTLMSSP_NEGOTIATE_ALWAYS_SIGN | NTLMSSP_NEGOTIATE_SEAL |
+		NTLMSSP_NEGOTIATE_SIGN | NTLMSSP_NEGOTIATE_VERSION;
+	if (!server->session_estab || ses->ntlmssp->sesskey_per_smbsess)
+		flags |= NTLMSSP_NEGOTIATE_KEY_XCH;
+
+	sec_blob->Version.ProductMajorVersion = LINUX_VERSION_MAJOR;
+	sec_blob->Version.ProductMinorVersion = LINUX_VERSION_PATCHLEVEL;
+	sec_blob->Version.ProductBuild = cpu_to_le16(SMB3_PRODUCT_BUILD);
+	sec_blob->Version.NTLMRevisionCurrent = NTLMSSP_REVISION_W2K3;
+
+	tmp = *pbuffer + sizeof(struct negotiate_message);
+	ses->ntlmssp->client_flags = flags;
+	sec_blob->NegotiateFlags = cpu_to_le32(flags);
+
+	/* these fields should be null in negotiate phase MS-NLMP 3.1.5.1.1 */
+	cifs_security_buffer_from_str(&sec_blob->DomainName,
+				      NULL,
+				      CIFS_MAX_DOMAINNAME_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
+
+	cifs_security_buffer_from_str(&sec_blob->WorkstationName,
+				      NULL,
+				      CIFS_MAX_WORKSTATION_LEN,
+				      *pbuffer, &tmp,
+				      nls_cp);
+
+	*buflen = tmp - *pbuffer;
+setup_ntlm_smb3_neg_ret:
+	return rc;
+}
+
+
 int build_ntlmssp_auth_blob(unsigned char **pbuffer,
 					u16 *buflen,
 				   struct cifs_ses *ses,