cifs: teach signing routines how to deal with arrays of pages in a smb_rqst

Use the smb_send_rqst helper function to kmap each page in the array
and update the hash for that chunk.
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

@@ -29,6 +29,7 @@
 #include "ntlmssp.h"
 #include <linux/ctype.h>
 #include <linux/random.h>
+#include <linux/highmem.h>
 
 /*
  * Calculate and return the CIFS signature based on the mac key and SMB PDU.
@@ -93,6 +94,16 @@ static int cifs_calc_signature(struct smb_rqst *rqst,
 		}
 	}
 
+	/* now hash over the rq_pages array */
+	for (i = 0; i < rqst->rq_npages; i++) {
+		struct kvec p_iov;
+
+		cifs_rqst_page_to_kvec(rqst, i, &p_iov);
+		crypto_shash_update(&server->secmech.sdescmd5->shash,
+					p_iov.iov_base, p_iov.iov_len);
+		kunmap(rqst->rq_pages[i]);
+	}
+
 	rc = crypto_shash_final(&server->secmech.sdescmd5->shash, signature);
 	if (rc)
 		cERROR(1, "%s: Could not generate md5 hash", __func__);

fs/cifs/cifsproto.h

@@ -36,6 +36,8 @@ extern struct smb_hdr *cifs_buf_get(void);
 extern void cifs_buf_release(void *);
 extern struct smb_hdr *cifs_small_buf_get(void);
 extern void cifs_small_buf_release(void *);
+extern void cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx,
+					struct kvec *iov);
 extern int smb_send(struct TCP_Server_Info *, struct smb_hdr *,
 			unsigned int /* length */);
 extern unsigned int _get_xid(void);

fs/cifs/smb2transport.c

@@ -30,6 +30,7 @@
 #include <linux/uaccess.h>
 #include <asm/processor.h>
 #include <linux/mempool.h>
+#include <linux/highmem.h>
 #include "smb2pdu.h"
 #include "cifsglob.h"
 #include "cifsproto.h"
@@ -95,6 +96,16 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
 		}
 	}
 
+	/* now hash over the rq_pages array */
+	for (i = 0; i < rqst->rq_npages; i++) {
+		struct kvec p_iov;
+
+		cifs_rqst_page_to_kvec(rqst, i, &p_iov);
+		crypto_shash_update(&server->secmech.sdeschmacsha256->shash,
+					p_iov.iov_base, p_iov.iov_len);
+		kunmap(rqst->rq_pages[i]);
+	}
+
 	rc = crypto_shash_final(&server->secmech.sdeschmacsha256->shash,
 				sigptr);
 	if (rc)

fs/cifs/transport.c

@@ -251,7 +251,7 @@ smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov, size_t n_vec,
  * The page will be kmapped and the address placed into iov_base. The length
  * will then be adjusted according to the ptailoff.
  */
-static void
+void
 cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx,
 			struct kvec *iov)
 {