Update negotiate protocol for SMB3.11 dialect

Send negotiate contexts when SMB3.11 dialect is negotiated
(ie the preauth and the encryption contexts) and
Initialize SMB3.11 preauth negotiate context salt to random bytes

Followon patch will update session setup and tree connect

Signed-off-by: Steve French <steve.french@primarydata.com>

1 files changed, 57 insertions, 2 deletions

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 0479e3c87a2c..b8b4f08ee094 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -304,6 +304,59 @@ small_smb2_init(__le16 smb2_command, struct cifs_tcon *tcon,
 	return rc;
 }
 
+#ifdef CONFIG_CIFS_SMB311
+/* offset is sizeof smb2_negotiate_req - 4 but rounded up to 8 bytes */
+#define OFFSET_OF_NEG_CONTEXT 0x68  /* sizeof(struct smb2_negotiate_req) - 4 */
+
+
+#define SMB2_PREAUTH_INTEGRITY_CAPABILITIES	cpu_to_le16(1)
+#define SMB2_ENCRYPTION_CAPABILITIES		cpu_to_le16(2)
+
+static void
+build_preauth_ctxt(struct smb2_preauth_neg_context *pneg_ctxt)
+{
+	pneg_ctxt->ContextType = SMB2_PREAUTH_INTEGRITY_CAPABILITIES;
+	pneg_ctxt->DataLength = cpu_to_le16(38);
+	pneg_ctxt->HashAlgorithmCount = cpu_to_le16(1);
+	pneg_ctxt->SaltLength = cpu_to_le16(SMB311_SALT_SIZE);
+	get_random_bytes(pneg_ctxt->Salt, SMB311_SALT_SIZE);
+	pneg_ctxt->HashAlgorithms = SMB2_PREAUTH_INTEGRITY_SHA512;
+}
+
+static void
+build_encrypt_ctxt(struct smb2_encryption_neg_context *pneg_ctxt)
+{
+	pneg_ctxt->ContextType = SMB2_ENCRYPTION_CAPABILITIES;
+	pneg_ctxt->DataLength = cpu_to_le16(6);
+	pneg_ctxt->CipherCount = cpu_to_le16(2);
+	pneg_ctxt->Ciphers[0] = SMB2_ENCRYPTION_AES128_GCM;
+	pneg_ctxt->Ciphers[1] = SMB2_ENCRYPTION_AES128_CCM;
+}
+
+static void
+assemble_neg_contexts(struct smb2_negotiate_req *req)
+{
+
+	/* +4 is to account for the RFC1001 len field */
+	char *pneg_ctxt = (char *)req + OFFSET_OF_NEG_CONTEXT + 4;
+
+	build_preauth_ctxt((struct smb2_preauth_neg_context *)pneg_ctxt);
+	/* Add 2 to size to round to 8 byte boundary */
+	pneg_ctxt += 2 + sizeof(struct smb2_preauth_neg_context);
+	build_encrypt_ctxt((struct smb2_encryption_neg_context *)pneg_ctxt);
+	req->NegotiateContextOffset = cpu_to_le32(OFFSET_OF_NEG_CONTEXT);
+	req->NegotiateContextCount = cpu_to_le16(2);
+	inc_rfc1001_len(req, 4 + sizeof(struct smb2_preauth_neg_context) + 2
+			+ sizeof(struct smb2_encryption_neg_context)); /* calculate hash */
+}
+#else
+static void assemble_neg_contexts(struct smb2_negotiate_req *req)
+{
+	return;
+}
+#endif /* SMB311 */
+
+
 /*
  *
  *	SMB2 Worker functions follow:
@@ -363,10 +416,12 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 	/* ClientGUID must be zero for SMB2.02 dialect */
 	if (ses->server->vals->protocol_id == SMB20_PROT_ID)
 		memset(req->ClientGUID, 0, SMB2_CLIENT_GUID_SIZE);
-	else
+	else {
 		memcpy(req->ClientGUID, server->client_guid,
 			SMB2_CLIENT_GUID_SIZE);
-
+		if (ses->server->vals->protocol_id == SMB311_PROT_ID)
+			assemble_neg_contexts(req);
+	}
 	iov[0].iov_base = (char *)req;
 	/* 4 for rfc1002 length field */
 	iov[0].iov_len = get_rfc1002_length(req) + 4;