Commit 7332f2a6 authored by Jeff Layton's avatar Jeff Layton Committed by Steve French
Browse files

cifs: eliminate some more premature cifsd exits 



If the tcpStatus is still CifsNew, the main cifs_demultiplex_loop can
break out prematurely in some cases. This is wrong as we will almost
always have other structures with pointers to the TCP_Server_Info. If
the main loop breaks under any other condition other than tcpStatus ==
CifsExiting, then it'll face a use-after-free situation.

I don't see any reason to treat a CifsNew tcpStatus differently than
CifsGood. I believe we'll still want to attempt to reconnect in either
case. What should happen in those situations is that the MIDs get marked
as MID_RETRY_NEEDED. This will make CIFSSMBNegotiate return -EAGAIN, and
then the caller can retry the whole thing on a newly reconnected socket.
If that fails again in the same way, the caller of cifs_get_smb_ses
should tear down the TCP_Server_Info struct.

Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarSteve French <sfrench@us.ibm.com>
parent 522bbe65

fs/cifs/connect.c

+12 −29
Original line number Diff line number Diff line
@@ -416,14 +416,6 @@ incomplete_rcv: 
			} else

				continue;

		} else if (length <= 0) {

			if (server->tcpStatus == CifsNew) {

				cFYI(1, "tcp session abend after SMBnegprot");

				/* some servers kill the TCP session rather than

				   returning an SMB negprot error, in which

				   case reconnecting here is not going to help,

				   and so simply return error to mount */

				break;

			}

			cFYI(1, "Reconnect after unexpected peek error %d",

				length);

			cifs_reconnect(server);
@@ -464,27 +456,18 @@ incomplete_rcv: 
			   an error on SMB negprot response */

			cFYI(1, "Negative RFC1002 Session Response Error 0x%x)",

				pdu_length);

			if (server->tcpStatus == CifsNew) {

				/* if nack on negprot (rather than

				ret of smb negprot error) reconnecting

				not going to help, ret error to mount */

				break;

			} else {

				/* give server a second to

				clean up before reconnect attempt */

			/* give server a second to clean up  */

			msleep(1000);

				/* always try 445 first on reconnect

				since we get NACK on some if we ever

				connected to port 139 (the NACK is

				since we do not begin with RFC1001

				session initialize frame) */

				server->addr.sockAddr.sin_port =

					htons(CIFS_PORT);

			/* always try 445 first on reconnect since we get NACK

			 * on some if we ever connected to port 139 (the NACK

			 * is since we do not begin with RFC1001 session

			 * initialize frame)

			 */

			server->addr.sockAddr.sin_port = htons(CIFS_PORT);

			cifs_reconnect(server);

			csocket = server->ssocket;

			wake_up(&server->response_q);

			continue;

			}

		} else if (temp != (char) 0) {

			cERROR(1, "Unknown RFC 1002 frame");

			cifs_dump_mem(" Received Data: ", (char *)smb_buffer,

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