cifs: update receive_encrypted_standard to handle compounded responses

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Paulo Alcantara <palcantara@suse.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

fs/cifs/cifsglob.h

@@ -76,6 +76,9 @@
 #define SMB_ECHO_INTERVAL_MAX 600
 #define SMB_ECHO_INTERVAL_DEFAULT 60
 
+/* maximum number of PDUs in one compound */
+#define MAX_COMPOUND 5
+
 /*
  * Default number of credits to keep available for SMB3.
  * This value is chosen somewhat arbitrarily. The Windows client
@@ -458,7 +461,7 @@ struct smb_version_operations {
 				 struct smb_rqst *, struct smb_rqst *);
 	int (*is_transform_hdr)(void *buf);
 	int (*receive_transform)(struct TCP_Server_Info *,
-				 struct mid_q_entry **);
+				 struct mid_q_entry **, char **, int *);
 	enum securityEnum (*select_sectype)(struct TCP_Server_Info *,
 			    enum securityEnum);
 	int (*next_header)(char *);

fs/cifs/connect.c

@@ -850,13 +850,14 @@ cifs_handle_standard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 static int
 cifs_demultiplex_thread(void *p)
 {
-	int length;
+	int i, num_mids, length;
 	struct TCP_Server_Info *server = p;
 	unsigned int pdu_length;
 	unsigned int next_offset;
 	char *buf = NULL;
 	struct task_struct *task_to_wake = NULL;
-	struct mid_q_entry *mid_entry;
+	struct mid_q_entry *mids[MAX_COMPOUND];
+	char *bufs[MAX_COMPOUND];
 
 	current->flags |= PF_MEMALLOC;
 	cifs_dbg(FYI, "Demultiplex PID: %d\n", task_pid_nr(current));
@@ -923,58 +924,75 @@ cifs_demultiplex_thread(void *p)
 				server->pdu_size = next_offset;
 		}
 
-		mid_entry = NULL;
+		memset(mids, 0, sizeof(mids));
+		memset(bufs, 0, sizeof(bufs));
+		num_mids = 0;
+
 		if (server->ops->is_transform_hdr &&
 		    server->ops->receive_transform &&
 		    server->ops->is_transform_hdr(buf)) {
 			length = server->ops->receive_transform(server,
-								&mid_entry);
+								mids,
+								bufs,
+								&num_mids);
 		} else {
-			mid_entry = server->ops->find_mid(server, buf);
+			mids[0] = server->ops->find_mid(server, buf);
+			bufs[0] = buf;
+			if (mids[0])
+				num_mids = 1;
 
-			if (!mid_entry || !mid_entry->receive)
-				length = standard_receive3(server, mid_entry);
+			if (!mids[0] || !mids[0]->receive)
+				length = standard_receive3(server, mids[0]);
 			else
-				length = mid_entry->receive(server, mid_entry);
+				length = mids[0]->receive(server, mids[0]);
 		}
 
 		if (length < 0) {
-			if (mid_entry)
-				cifs_mid_q_entry_release(mid_entry);
+			for (i = 0; i < num_mids; i++)
+				if (mids[i])
+					cifs_mid_q_entry_release(mids[i]);
 			continue;
 		}
 
 		if (server->large_buf)
 			buf = server->bigbuf;
 
+
 		server->lstrp = jiffies;
-		if (mid_entry != NULL) {
-			mid_entry->resp_buf_size = server->pdu_size;
-			if ((mid_entry->mid_flags & MID_WAIT_CANCELLED) &&
-			     mid_entry->mid_state == MID_RESPONSE_RECEIVED &&
+
+		for (i = 0; i < num_mids; i++) {
+			if (mids[i] != NULL) {
+				mids[i]->resp_buf_size = server->pdu_size;
+				if ((mids[i]->mid_flags & MID_WAIT_CANCELLED) &&
+				    mids[i]->mid_state == MID_RESPONSE_RECEIVED &&
 				    server->ops->handle_cancelled_mid)
 					server->ops->handle_cancelled_mid(
-							mid_entry->resp_buf,
+							mids[i]->resp_buf,
 							server);
 
-			if (!mid_entry->multiRsp || mid_entry->multiEnd)
-				mid_entry->callback(mid_entry);
+				if (!mids[i]->multiRsp || mids[i]->multiEnd)
+					mids[i]->callback(mids[i]);
 
-			cifs_mid_q_entry_release(mid_entry);
+				cifs_mid_q_entry_release(mids[i]);
 			} else if (server->ops->is_oplock_break &&
-			   server->ops->is_oplock_break(buf, server)) {
+				   server->ops->is_oplock_break(bufs[i],
+								server)) {
 				cifs_dbg(FYI, "Received oplock break\n");
 			} else {
-			cifs_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n",
+				cifs_dbg(VFS, "No task to wake, unknown frame "
+					 "received! NumMids %d\n",
 					 atomic_read(&midCount));
-			cifs_dump_mem("Received Data is: ", buf,
+				cifs_dump_mem("Received Data is: ", bufs[i],
 					      HEADER_SIZE(server));
 #ifdef CONFIG_CIFS_DEBUG2
 				if (server->ops->dump_detail)
-				server->ops->dump_detail(buf, server);
+					server->ops->dump_detail(bufs[i],
+								 server);
 				cifs_dump_mids(server);
 #endif /* CIFS_DEBUG2 */
 			}
+		}
+
 		if (pdu_length > server->pdu_size) {
 			if (!allocate_buffers(server))
 				continue;

fs/cifs/smb2ops.c

@@ -2942,13 +2942,20 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid)
 
 static int
 receive_encrypted_standard(struct TCP_Server_Info *server,
-			   struct mid_q_entry **mid)
+			   struct mid_q_entry **mids, char **bufs,
+			   int *num_mids)
 {
-	int length;
+	int ret, length;
 	char *buf = server->smallbuf;
+	char *tmpbuf;
+	struct smb2_sync_hdr *shdr;
 	unsigned int pdu_length = server->pdu_size;
 	unsigned int buf_size;
 	struct mid_q_entry *mid_entry;
+	int next_is_large;
+	char *next_buffer = NULL;
+
+	*num_mids = 0;
 
 	/* switch to large buffer if too big for a small one */
 	if (pdu_length > MAX_CIFS_SMALL_BUFFER_SIZE) {
@@ -2969,24 +2976,61 @@ receive_encrypted_standard(struct TCP_Server_Info *server,
 	if (length)
 		return length;
 
+	next_is_large = server->large_buf;
+ one_more:
+	shdr = (struct smb2_sync_hdr *)buf;
+	if (shdr->NextCommand) {
+		if (next_is_large) {
+			tmpbuf = server->bigbuf;
+			next_buffer = (char *)cifs_buf_get();
+		} else {
+			tmpbuf = server->smallbuf;
+			next_buffer = (char *)cifs_small_buf_get();
+		}
+		memcpy(next_buffer,
+		       tmpbuf + le32_to_cpu(shdr->NextCommand),
+		       pdu_length - le32_to_cpu(shdr->NextCommand));
+	}
+
 	mid_entry = smb2_find_mid(server, buf);
 	if (mid_entry == NULL)
 		cifs_dbg(FYI, "mid not found\n");
 	else {
 		cifs_dbg(FYI, "mid found\n");
 		mid_entry->decrypted = true;
+		mid_entry->resp_buf_size = server->pdu_size;
 	}
 
-	*mid = mid_entry;
+	if (*num_mids >= MAX_COMPOUND) {
+		cifs_dbg(VFS, "too many PDUs in compound\n");
+		return -1;
+	}
+	bufs[*num_mids] = buf;
+	mids[(*num_mids)++] = mid_entry;
 
 	if (mid_entry && mid_entry->handle)
-		return mid_entry->handle(server, mid_entry);
+		ret = mid_entry->handle(server, mid_entry);
+	else
+		ret = cifs_handle_standard(server, mid_entry);
+
+	if (ret == 0 && shdr->NextCommand) {
+		pdu_length -= le32_to_cpu(shdr->NextCommand);
+		server->large_buf = next_is_large;
+		if (next_is_large)
+			server->bigbuf = next_buffer;
+		else
+			server->smallbuf = next_buffer;
+
+		buf += le32_to_cpu(shdr->NextCommand);
+		goto one_more;
+	}
 
-	return cifs_handle_standard(server, mid_entry);
+	return ret;
 }
 
 static int
-smb3_receive_transform(struct TCP_Server_Info *server, struct mid_q_entry **mid)
+smb3_receive_transform(struct TCP_Server_Info *server,
+		       struct mid_q_entry **mids, char **bufs, int *num_mids)
 {
 	char *buf = server->smallbuf;
 	unsigned int pdu_length = server->pdu_size;
@@ -3009,10 +3053,11 @@ smb3_receive_transform(struct TCP_Server_Info *server, struct mid_q_entry **mid)
 		return -ECONNABORTED;
 	}
 
+	/* TODO: add support for compounds containing READ. */
 	if (pdu_length > CIFSMaxBufSize + MAX_HEADER_SIZE(server))
-		return receive_encrypted_read(server, mid);
+		return receive_encrypted_read(server, &mids[0]);
 
-	return receive_encrypted_standard(server, mid);
+	return receive_encrypted_standard(server, mids, bufs, num_mids);
 }
 
 int

fs/cifs/transport.c

@@ -383,8 +383,6 @@ __smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 	return rc;
 }
 
-#define MAX_COMPOUND 5
-
 static int
 smb_send_rqst(struct TCP_Server_Info *server, int num_rqst,
 	      struct smb_rqst *rqst, int flags)