Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6

* git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  cifs: don't always drop malformed replies on the floor (try #3)
  cifs: clean up checks in cifs_echo_request
  [CIFS] Do not send SMBEcho requests on new sockets until SMBNegotiate

fs/cifs/cifsglob.h

@@ -188,6 +188,8 @@ struct TCP_Server_Info {
 	/* multiplexed reads or writes */
 	unsigned int maxBuf;	/* maxBuf specifies the maximum */
 	/* message size the server can send or receive for non-raw SMBs */
+	/* maxBuf is returned by SMB NegotiateProtocol so maxBuf is only 0 */
+	/* when socket is setup (and during reconnect) before NegProt sent */
 	unsigned int max_rw;	/* maxRw specifies the maximum */
 	/* message size the server can send or receive for */
 	/* SMB_COM_WRITE_RAW or SMB_COM_READ_RAW. */
@@ -652,7 +654,7 @@ static inline void free_dfs_info_array(struct dfs_info3_param *param,
 #define   MID_REQUEST_SUBMITTED 2
 #define   MID_RESPONSE_RECEIVED 4
 #define   MID_RETRY_NEEDED      8 /* session closed while this request out */
-#define   MID_NO_RESP_NEEDED 0x10
+#define   MID_RESPONSE_MALFORMED 0x10
 
 /* Types of response buffer returned from SendReceive2 */
 #define   CIFS_NO_BUFFER        0    /* Response buffer not returned */

fs/cifs/connect.c

@@ -338,10 +338,11 @@ cifs_echo_request(struct work_struct *work)
 					struct TCP_Server_Info, echo.work);
 
 	/*
-	 * We cannot send an echo until the NEGOTIATE_PROTOCOL request is done.
-	 * Also, no need to ping if we got a response recently
+	 * We cannot send an echo until the NEGOTIATE_PROTOCOL request is
+	 * done, which is indicated by maxBuf != 0. Also, no need to ping if
+	 * we got a response recently
 	 */
-	if (server->tcpStatus != CifsGood ||
+	if (server->maxBuf == 0 ||
 	    time_before(jiffies, server->lstrp + SMB_ECHO_INTERVAL - HZ))
 		goto requeue_echo;
 
@@ -585,11 +586,20 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
 		total_read += 4; /* account for rfc1002 hdr */
 
 		dump_smb(smb_buffer, total_read);
-		if (checkSMB(smb_buffer, smb_buffer->Mid, total_read)) {
+
+		/*
+		 * We know that we received enough to get to the MID as we
+		 * checked the pdu_length earlier. Now check to see
+		 * if the rest of the header is OK. We borrow the length
+		 * var for the rest of the loop to avoid a new stack var.
+		 *
+		 * 48 bytes is enough to display the header and a little bit
+		 * into the payload for debugging purposes.
+		 */
+		length = checkSMB(smb_buffer, smb_buffer->Mid, total_read);
+		if (length != 0)
 			cifs_dump_mem("Bad SMB: ", smb_buffer,
-					total_read < 48 ? total_read : 48);
-			continue;
-		}
+					min_t(unsigned int, total_read, 48));
 
 		mid_entry = NULL;
 		server->lstrp = jiffies;
@@ -601,7 +611,8 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
 			if ((mid_entry->mid == smb_buffer->Mid) &&
 			    (mid_entry->midState == MID_REQUEST_SUBMITTED) &&
 			    (mid_entry->command == smb_buffer->Command)) {
-				if (check2ndT2(smb_buffer,server->maxBuf) > 0) {
+				if (length == 0 &&
+				   check2ndT2(smb_buffer, server->maxBuf) > 0) {
 					/* We have a multipart transact2 resp */
 					isMultiRsp = true;
 					if (mid_entry->resp_buf) {
@@ -636,7 +647,12 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
 				mid_entry->resp_buf = smb_buffer;
 				mid_entry->largeBuf = isLargeBuf;
 multi_t2_fnd:
-				mid_entry->midState = MID_RESPONSE_RECEIVED;
+				if (length == 0)
+					mid_entry->midState =
+							MID_RESPONSE_RECEIVED;
+				else
+					mid_entry->midState =
+							MID_RESPONSE_MALFORMED;
 #ifdef CONFIG_CIFS_STATS2
 				mid_entry->when_received = jiffies;
 #endif
@@ -657,6 +673,9 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
 				else
 					smallbuf = NULL;
 			}
+		} else if (length != 0) {
+			/* response sanity checks failed */
+			continue;
 		} else if (!is_valid_oplock_break(smb_buffer, server) &&
 			   !isMultiRsp) {
 			cERROR(1, "No task to wake, unknown frame received! "

fs/cifs/transport.c

@@ -457,6 +457,9 @@ sync_mid_result(struct mid_q_entry *mid, struct TCP_Server_Info *server)
 	case MID_RETRY_NEEDED:
 		rc = -EAGAIN;
 		break;
+	case MID_RESPONSE_MALFORMED:
+		rc = -EIO;
+		break;
 	default:
 		cERROR(1, "%s: invalid mid state mid=%d state=%d", __func__,
 			mid->mid, mid->midState);