cifs: change signing routines to deal with smb_rqst structs

We need a way to represent a call to be sent on the wire that does not
require having all of the page data kmapped. Behold the smb_rqst struct.
This new struct represents an array of kvecs immediately followed by an
array of pages.

Convert the signing routines to use these structs under the hood and
turn the existing functions for this into wrappers around that. For now,
we're just changing these functions to take different args. Later, we'll
teach them how to deal with arrays of pages.

Reviewed-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/cifsencrypt.c

@@ -37,11 +37,13 @@
  * the sequence number before this function is called. Also, this function
  * should be called with the server->srv_mutex held.
  */
-static int cifs_calc_signature(const struct kvec *iov, int n_vec,
+static int cifs_calc_signature(struct smb_rqst *rqst,
 			struct TCP_Server_Info *server, char *signature)
 {
 	int i;
 	int rc;
+	struct kvec *iov = rqst->rq_iov;
+	int n_vec = rqst->rq_nvec;
 
 	if (iov == NULL || signature == NULL || server == NULL)
 		return -EINVAL;
@@ -99,12 +101,12 @@ static int cifs_calc_signature(const struct kvec *iov, int n_vec,
 }
 
 /* must be called with server->srv_mutex held */
-int cifs_sign_smbv(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
+int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server,
 		   __u32 *pexpected_response_sequence_number)
 {
 	int rc = 0;
 	char smb_signature[20];
-	struct smb_hdr *cifs_pdu = (struct smb_hdr *)iov[0].iov_base;
+	struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
 
 	if ((cifs_pdu == NULL) || (server == NULL))
 		return -EINVAL;
@@ -125,7 +127,7 @@ int cifs_sign_smbv(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
 	*pexpected_response_sequence_number = server->sequence_number++;
 	server->sequence_number++;
 
-	rc = cifs_calc_signature(iov, n_vec, server, smb_signature);
+	rc = cifs_calc_signature(rqst, server, smb_signature);
 	if (rc)
 		memset(cifs_pdu->Signature.SecuritySignature, 0, 8);
 	else
@@ -134,6 +136,15 @@ int cifs_sign_smbv(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
 	return rc;
 }
 
+int cifs_sign_smbv(struct kvec *iov, int n_vec, struct TCP_Server_Info *server,
+		   __u32 *pexpected_response_sequence)
+{
+	struct smb_rqst rqst = { .rq_iov = iov,
+				 .rq_nvec = n_vec };
+
+	return cifs_sign_rqst(&rqst, server, pexpected_response_sequence);
+}
+
 /* must be called with server->srv_mutex held */
 int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server,
 		  __u32 *pexpected_response_sequence_number)
@@ -147,14 +158,14 @@ int cifs_sign_smb(struct smb_hdr *cifs_pdu, struct TCP_Server_Info *server,
 			      pexpected_response_sequence_number);
 }
 
-int cifs_verify_signature(struct kvec *iov, unsigned int nr_iov,
+int cifs_verify_signature(struct smb_rqst *rqst,
 			  struct TCP_Server_Info *server,
 			  __u32 expected_sequence_number)
 {
 	unsigned int rc;
 	char server_response_sig[8];
 	char what_we_think_sig_should_be[20];
-	struct smb_hdr *cifs_pdu = (struct smb_hdr *)iov[0].iov_base;
+	struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base;
 
 	if (cifs_pdu == NULL || server == NULL)
 		return -EINVAL;
@@ -186,8 +197,7 @@ int cifs_verify_signature(struct kvec *iov, unsigned int nr_iov,
 	cifs_pdu->Signature.Sequence.Reserved = 0;
 
 	mutex_lock(&server->srv_mutex);
-	rc = cifs_calc_signature(iov, nr_iov, server,
-				 what_we_think_sig_should_be);
+	rc = cifs_calc_signature(rqst, server, what_we_think_sig_should_be);
 	mutex_unlock(&server->srv_mutex);
 
 	if (rc)

fs/cifs/cifsglob.h

@@ -162,6 +162,20 @@ struct cifs_cred {
  *****************************************************************
  */
 
+/*
+ * A smb_rqst represents a complete request to be issued to a server. It's
+ * formed by a kvec array, followed by an array of pages. Page data is assumed
+ * to start at the beginning of the first page.
+ */
+struct smb_rqst {
+	struct kvec	*rq_iov;	/* array of kvecs */
+	unsigned int	rq_nvec;	/* number of kvecs in array */
+	struct page	**rq_pages;	/* pointer to array of page ptrs */
+	unsigned int	rq_npages;	/* number pages in array */
+	unsigned int	rq_pagesz;	/* page size to use */
+	unsigned int	rq_tailsz;	/* length of last page */
+};
+
 enum smb_version {
 	Smb_1 = 1,
 	Smb_21,

fs/cifs/cifsproto.h

@@ -24,6 +24,7 @@
 
 struct statfs;
 struct smb_vol;
+struct smb_rqst;
 
 /*
  *****************************************************************
@@ -394,10 +395,12 @@ extern void sesInfoFree(struct cifs_ses *);
 extern struct cifs_tcon *tconInfoAlloc(void);
 extern void tconInfoFree(struct cifs_tcon *);
 
-extern int cifs_sign_smb(struct smb_hdr *, struct TCP_Server_Info *, __u32 *);
+extern int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server,
+		   __u32 *pexpected_response_sequence_number);
 extern int cifs_sign_smbv(struct kvec *iov, int n_vec, struct TCP_Server_Info *,
 			  __u32 *);
-extern int cifs_verify_signature(struct kvec *iov, unsigned int nr_iov,
+extern int cifs_sign_smb(struct smb_hdr *, struct TCP_Server_Info *, __u32 *);
+extern int cifs_verify_signature(struct smb_rqst *rqst,
 				 struct TCP_Server_Info *server,
 				__u32 expected_sequence_number);
 extern int SMBNTencrypt(unsigned char *, unsigned char *, unsigned char *,

fs/cifs/cifssmb.c

@@ -1541,6 +1541,8 @@ cifs_readv_callback(struct mid_q_entry *mid)
 	struct cifs_readdata *rdata = mid->callback_data;
 	struct cifs_tcon *tcon = tlink_tcon(rdata->cfile->tlink);
 	struct TCP_Server_Info *server = tcon->ses->server;
+	struct smb_rqst rqst = { .rq_iov = rdata->iov,
+				 .rq_nvec = rdata->nr_iov };
 
 	cFYI(1, "%s: mid=%llu state=%d result=%d bytes=%u", __func__,
 		mid->mid, mid->mid_state, rdata->result, rdata->bytes);
@@ -1552,9 +1554,8 @@ cifs_readv_callback(struct mid_q_entry *mid)
 		    (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
 			int rc = 0;
 
-			rc = cifs_verify_signature(rdata->iov, rdata->nr_iov,
-						   server,
-						   mid->sequence_number + 1);
+			rc = cifs_verify_signature(&rqst, server,
+						  mid->sequence_number + 1);
 			if (rc)
 				cERROR(1, "SMB signature verification returned "
 				       "error = %d", rc);

fs/cifs/transport.c

@@ -504,11 +504,13 @@ cifs_check_receive(struct mid_q_entry *mid, struct TCP_Server_Info *server,
 	if (server->sec_mode & (SECMODE_SIGN_REQUIRED | SECMODE_SIGN_ENABLED)) {
 		struct kvec iov;
 		int rc = 0;
+		struct smb_rqst rqst = { .rq_iov = &iov,
+					 .rq_nvec = 1 };
 
 		iov.iov_base = mid->resp_buf;
 		iov.iov_len = len;
 		/* FIXME: add code to kill session */
-		rc = cifs_verify_signature(&iov, 1, server,
+		rc = cifs_verify_signature(&rqst, server,
 					   mid->sequence_number + 1);
 		if (rc)
 			cERROR(1, "SMB signature verification returned error = "