[PATCH] libertas: move firmware lifetime handling to firmware.c

[Dan Williams <dcbw@redhat.com>]

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>
---
Tested firmware loading on USB (8388), CS (8385), and SDIO (8686).

diff --git a/drivers/net/wireless/libertas/firmware.c b/drivers/net/wireless/libertas/firmware.c
index c0f9e7e..51b92b5 100644
--- a/drivers/net/wireless/libertas/firmware.c
+++ b/drivers/net/wireless/libertas/firmware.c
@@ -49,14 +49,19 @@ static void main_firmware_cb(const struct firmware *firmware, void *context)
 		/* Failed to find firmware: try next table entry */
 		load_next_firmware_from_table(priv);
 		return;
 	}
 
 	/* Firmware found! */
 	lbs_fw_loaded(priv, 0, priv->helper_fw, firmware);
+	if (priv->helper_fw) {
+		release_firmware (priv->helper_fw);
+		priv->helper_fw = NULL;
+	}
+	release_firmware (firmware);
 }
 
 static void helper_firmware_cb(const struct firmware *firmware, void *context)
 {
 	struct lbs_private *priv = context;
 
 	if (!firmware) {
diff --git a/drivers/net/wireless/libertas/if_cs.c b/drivers/net/wireless/libertas/if_cs.c
index c94dd68..ef8c98e 100644
--- a/drivers/net/wireless/libertas/if_cs.c
+++ b/drivers/net/wireless/libertas/if_cs.c
@@ -750,22 +750,22 @@ static void if_cs_prog_firmware(struct lbs_private *priv, int ret,
 	}
 
 	/* Load the firmware */
 	ret = if_cs_prog_helper(card, helper);
 	if (ret == 0 && (card->model != MODEL_8305))
 		ret = if_cs_prog_real(card, mainfw);
 	if (ret)
-		goto out;
+		return;
 
 	/* Now actually get the IRQ */
 	ret = request_irq(card->p_dev->irq, if_cs_interrupt,
 		IRQF_SHARED, DRV_NAME, card);
 	if (ret) {
 		pr_err("error in request_irq\n");
-		goto out;
+		return;
 	}
 
 	/*
 	 * Clear any interrupt cause that happened while sending
 	 * firmware/initializing card
 	 */
 	if_cs_write16(card, IF_CS_CARD_INT_CAUSE, IF_CS_BIT_MASK);
@@ -773,18 +773,14 @@ static void if_cs_prog_firmware(struct lbs_private *priv, int ret,
 
 	/* And finally bring the card up */
 	priv->fw_ready = 1;
 	if (lbs_start_card(priv) != 0) {
 		pr_err("could not activate card\n");
 		free_irq(card->p_dev->irq, card);
 	}
-
-out:
-	release_firmware(helper);
-	release_firmware(mainfw);
 }
 
 
 /********************************************************************/
 /* Callback functions for libertas.ko                               */
 /********************************************************************/
 
diff --git a/drivers/net/wireless/libertas/if_sdio.c b/drivers/net/wireless/libertas/if_sdio.c
index 4557833..991238a 100644
--- a/drivers/net/wireless/libertas/if_sdio.c
+++ b/drivers/net/wireless/libertas/if_sdio.c
@@ -704,28 +704,24 @@ static void if_sdio_do_prog_firmware(struct lbs_private *priv, int ret,
 	if (ret) {
 		pr_err("failed to find firmware (%d)\n", ret);
 		return;
 	}
 
 	ret = if_sdio_prog_helper(card, helper);
 	if (ret)
-		goto out;
+		return;
 
 	lbs_deb_sdio("Helper firmware loaded\n");
 
 	ret = if_sdio_prog_real(card, mainfw);
 	if (ret)
-		goto out;
+		return;
 
 	lbs_deb_sdio("Firmware loaded\n");
 	if_sdio_finish_power_on(card);
-
-out:
-	release_firmware(helper);
-	release_firmware(mainfw);
 }
 
 static int if_sdio_prog_firmware(struct if_sdio_card *card)
 {
 	int ret;
 	u16 scratch;
 
diff --git a/drivers/net/wireless/libertas/if_spi.c b/drivers/net/wireless/libertas/if_spi.c
index 4bb6574..87ff0ca 100644
--- a/drivers/net/wireless/libertas/if_spi.c
+++ b/drivers/net/wireless/libertas/if_spi.c
@@ -1090,19 +1090,15 @@ static int if_spi_init_card(struct if_spi_card *card)
 	}
 
 	err = spu_set_interrupt_mode(card, 0, 1);
 	if (err)
 		goto out;
 
 out:
-	release_firmware(helper);
-	release_firmware(mainfw);
-
 	lbs_deb_leave_args(LBS_DEB_SPI, "err %d\n", err);
-
 	return err;
 }
 
 static void if_spi_resume_worker(struct work_struct *work)
 {
 	struct if_spi_card *card;
 
diff --git a/drivers/net/wireless/libertas/if_usb.c b/drivers/net/wireless/libertas/if_usb.c
index 2798077..dff08a2 100644
--- a/drivers/net/wireless/libertas/if_usb.c
+++ b/drivers/net/wireless/libertas/if_usb.c
@@ -840,15 +840,15 @@ static void if_usb_prog_firmware(struct lbs_private *priv, int ret,
 		pr_err("failed to find firmware (%d)\n", ret);
 		goto done;
 	}
 
 	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 */
 	usb_kill_urb(cardp->rx_urb);
 	usb_kill_urb(cardp->tx_urb);
 
 	cardp->fwlastblksent = 0;
@@ -857,15 +857,15 @@ static void if_usb_prog_firmware(struct lbs_private *priv, int ret,
 	cardp->fwfinalblk = 0;
 	cardp->bootcmdresp = 0;
 
 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;
 	do {
 		int j = 0;
 		i++;
 		if_usb_issue_boot_command(cardp, BOOT_CMD_FW_BY_USB);
@@ -879,22 +879,22 @@ restart:
 	if (cardp->bootcmdresp == BOOT_CMD_RESP_NOT_SUPPORTED) {
 		/* Return to normal operation */
 		ret = -EOPNOTSUPP;
 		usb_kill_urb(cardp->rx_urb);
 		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;
 
 	cardp->totalbytes = 0;
 	cardp->fwlastblksent = 0;
 	cardp->CRC_OK = 1;
@@ -917,37 +917,34 @@ restart:
 		if (--reset_count >= 0) {
 			if_usb_reset_device(cardp);
 			goto 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);
 
 	/*
 	 * EHS_REMOVE_WAKEUP is not supported on all versions of the firmware.
 	 */
 	priv->wol_criteria = EHS_REMOVE_WAKEUP;
 	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);
 }
 
 
 #ifdef CONFIG_PM
 static int if_usb_suspend(struct usb_interface *intf, pm_message_t message)
 {