Commit 0fe4c6fc authored by Stefan Richter's avatar Stefan Richter
Browse files

ieee1394: raw1394: prevent unloading of low-level driver 

Unloading the low-level driver module of a FireWire host can lead to
all sorts of trouble if a raw1394 userspace client is using the host.
Just disallow it by incrementing the LLD's module reference count on
a RAW1394_REQ_SET_CARD write operation.  Decrement it when the file
is closed.

This feature wouldn't be relevant if "modprobe -r video1394" or
"modprobe -r dv1394" didn't automatically unload ohci1394 too.
http://bugzilla.kernel.org/show_bug.cgi?id=7701



Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: default avatarDan Dennedy <dan@dennedy.org>
parent 12ba145c

drivers/ieee1394/raw1394.c

+29 −19
Original line number Diff line number Diff line
@@ -636,13 +636,22 @@ static int state_initialized(struct file_info *fi, struct pending_request *req) 


	case RAW1394_REQ_SET_CARD:

		spin_lock_irqsave(&host_info_lock, flags);

		if (req->req.misc < host_count) {

			list_for_each_entry(hi, &host_info_list, list) {

		if (req->req.misc >= host_count) {

			req->req.error = RAW1394_ERROR_INVALID_ARG;

			goto out_set_card;

		}

		list_for_each_entry(hi, &host_info_list, list)

			if (!req->req.misc--)

				break;

			}

			get_device(&hi->host->device);	// XXX Need to handle failure case

		get_device(&hi->host->device); /* FIXME handle failure case */

		list_add_tail(&fi->list, &hi->file_info_list);



		/* prevent unloading of the host's low-level driver */

		if (!try_module_get(hi->host->driver->owner)) {

			req->req.error = RAW1394_ERROR_ABORTED;

			goto out_set_card;

		}

		WARN_ON(fi->host);

		fi->host = hi->host;

		fi->state = connected;
@@ -650,13 +659,9 @@ static int state_initialized(struct file_info *fi, struct pending_request *req) 
		req->req.generation = get_hpsb_generation(fi->host);

		req->req.misc = (fi->host->node_id << 16)

				| fi->host->node_count;

			if (fi->protocol_version > 3) {

				req->req.misc |=

				    NODEID_TO_NODE(fi->host->irm_id) << 8;

			}

		} else {

			req->req.error = RAW1394_ERROR_INVALID_ARG;

		}

		if (fi->protocol_version > 3)

			req->req.misc |= NODEID_TO_NODE(fi->host->irm_id) << 8;

out_set_card:

		spin_unlock_irqrestore(&host_info_lock, flags);



		req->req.length = 0;
@@ -2955,6 +2960,11 @@ static int raw1394_release(struct inode *inode, struct file *file) 
		put_device(&fi->host->device);

	}



	spin_lock_irqsave(&host_info_lock, flags);

	if (fi->host)

		module_put(fi->host->driver->owner);

	spin_unlock_irqrestore(&host_info_lock, flags);



	kfree(fi);



	return 0;

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