libertas: move firmware lifetime handling to firmware.c

Previously, each bus type was responsible for freeing the firmware
structure, but some did that badly.  Move responsibility for freeing
firmware into firmware.c so that it's done once and correctly, instead
of happening in multiple places in bus-specific code.

This fixes a use-after-free bug found by Dr. H. Nikolaus Schaller where
the SDIO code forgot to NULL priv->helper_fw after freeing it.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 7 insertions, 10 deletions

diff --git a/drivers/net/wireless/libertas/if_usb.c b/drivers/net/wireless/libertas/if_usb.c
index 27980778d99..dff08a2896a 100644
--- a/drivers/net/wireless/libertas/if_usb.c
+++ b/drivers/net/wireless/libertas/if_usb.c
@@ -844,7 +844,7 @@ static void if_usb_prog_firmware(struct lbs_private *priv, int ret,
 	cardp->fw = fw;
 	if (check_fwfile_format(cardp->fw->data, cardp->fw->size)) {
 		ret = -EINVAL;
-		goto release_fw;
+		goto done;
 	}
 
 	/* Cancel any pending usb business */
@@ -861,7 +861,7 @@ restart:
 	if (if_usb_submit_rx_urb_fwload(cardp) < 0) {
 		lbs_deb_usbd(&cardp->udev->dev, "URB submission is failed\n");
 		ret = -EIO;
-		goto release_fw;
+		goto done;
 	}
 
 	cardp->bootcmdresp = 0;
@@ -883,14 +883,14 @@ restart:
 		usb_kill_urb(cardp->tx_urb);
 		if (if_usb_submit_rx_urb(cardp) < 0)
 			ret = -EIO;
-		goto release_fw;
+		goto done;
 	} else if (cardp->bootcmdresp <= 0) {
 		if (--reset_count >= 0) {
 			if_usb_reset_device(cardp);
 			goto restart;
 		}
 		ret = -EIO;
-		goto release_fw;
+		goto done;
 	}
 
 	i = 0;
@@ -921,14 +921,14 @@ restart:
 
 		pr_info("FW download failure, time = %d ms\n", i * 100);
 		ret = -EIO;
-		goto release_fw;
+		goto done;
 	}
 
 	cardp->priv->fw_ready = 1;
 	if_usb_submit_rx_urb(cardp);
 
 	if (lbs_start_card(priv))
-		goto release_fw;
+		goto done;
 
 	if_usb_setup_firmware(priv);
 
@@ -939,11 +939,8 @@ restart:
 	if (lbs_host_sleep_cfg(priv, priv->wol_criteria, NULL))
 		priv->ehs_remove_supported = false;
 
- release_fw:
-	release_firmware(cardp->fw);
-	cardp->fw = NULL;
-
  done:
+	cardp->fw = NULL;
 	lbs_deb_leave(LBS_DEB_USB);
 }