firewire: cdev: tcodes input validation

The behaviour of fw-transaction.c::fw_send_request is ill-defined for
any other tcodes than read/ write/ lock request tcodes.  Therefore
prevent requests with wrong tcodes from entering the transaction layer.

Maybe fw_send_request should check them itself, but I am not inclined to
change it and fw_fill_request from void-valued functions to ones which
return error codes and pass those up.  Besides, maybe fw_send_request is
going to support one more tcode than ioctl_send_request in the future
(TCODE_STREAM_DATA).

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

diff --git a/drivers/firewire/fw-cdev.c b/drivers/firewire/fw-cdev.c
index 75bbd66..a320ab4 100644 (file)
--- a/drivers/firewire/fw-cdev.c
+++ b/drivers/firewire/fw-cdev.c
@@ -398,6 +398,7 @@ static int ioctl_send_request(struct client *client, void *buffer)
        struct fw_device *device = client->device;
        struct fw_cdev_send_request *request = buffer;
        struct response *response;
+       int ret;
 
        /* What is the biggest size we'll accept, really? */
        if (request->length > 4096)
@@ -414,8 +415,26 @@ static int ioctl_send_request(struct client *client, void *buffer)
        if (request->data &&
            copy_from_user(response->response.data,
                           u64_to_uptr(request->data), request->length)) {
-               kfree(response);
-               return -EFAULT;
+               ret = -EFAULT;
+               goto err;
+       }
+
+       switch (request->tcode) {
+       case TCODE_WRITE_QUADLET_REQUEST:
+       case TCODE_WRITE_BLOCK_REQUEST:
+       case TCODE_READ_QUADLET_REQUEST:
+       case TCODE_READ_BLOCK_REQUEST:
+       case TCODE_LOCK_MASK_SWAP:
+       case TCODE_LOCK_COMPARE_SWAP:
+       case TCODE_LOCK_FETCH_ADD:
+       case TCODE_LOCK_LITTLE_ADD:
+       case TCODE_LOCK_BOUNDED_ADD:
+       case TCODE_LOCK_WRAP_ADD:
+       case TCODE_LOCK_VENDOR_DEPENDENT:
+               break;
+       default:
+               ret = -EINVAL;
+               goto err;
        }
 
        response->resource.release = release_transaction;
@@ -434,6 +453,10 @@ static int ioctl_send_request(struct client *client, void *buffer)
                return sizeof(request) + request->length;
        else
                return sizeof(request);
+ err:
+       kfree(response);
+
+       return ret;
 }
 
 struct address_handler {