[PATCH v2] ath9k: hif_usb: Fix use-after-free in ath9k_hif_usb_reg_in_cb()
From: Fedor Pchelkin <hidden>
Date: 2022-10-08 11:50:00
Also in:
linux-wireless, lkml
Subsystem:
atheros ath generic utilities, qualcomm atheros ath9k wireless driver, the rest · Maintainers:
Jeff Johnson, Toke Høiland-Jørgensen, Linus Torvalds
It is possible that skb is freed in ath9k_htc_rx_msg(), then
usb_submit_urb() fails and we try to free skb again. It causes
use-after-free bug. Moreover, if alloc_skb() fails, urb->context becomes
NULL but rx_buf is not freed and there can be a memory leak.
The patch removes unnecessary nskb and makes skb processing more clear: it
is supposed that ath9k_htc_rx_msg() either frees old skb or passes its
managing to another callback function.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 3deff76095c4 ("ath9k_htc: Increase URB count for REG_IN pipe")
Signed-off-by: Fedor Pchelkin <redacted>
Signed-off-by: Alexey Khoroshilov <redacted>
---
v1->v2: add comment about freeing an skb and remove double blank line
drivers/net/wireless/ath/ath9k/hif_usb.c | 28 +++++++++++++-----------
1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index 4d9002a9d082..401b408cb7a4 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c@@ -708,14 +708,13 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb) struct rx_buf *rx_buf = (struct rx_buf *)urb->context; struct hif_device_usb *hif_dev = rx_buf->hif_dev; struct sk_buff *skb = rx_buf->skb; - struct sk_buff *nskb; int ret; if (!skb) return; if (!hif_dev) - goto free; + goto free_skb; switch (urb->status) { case 0:
@@ -724,7 +723,7 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb) case -ECONNRESET: case -ENODEV: case -ESHUTDOWN: - goto free; + goto free_skb; default: skb_reset_tail_pointer(skb); skb_trim(skb, 0);
@@ -735,25 +734,27 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb) if (likely(urb->actual_length != 0)) { skb_put(skb, urb->actual_length); - /* Process the command first */ + /* + * Process the command first. + * skb is either freed here or passed to be + * managed to another callback function. + */ ath9k_htc_rx_msg(hif_dev->htc_handle, skb, skb->len, USB_REG_IN_PIPE); - - nskb = alloc_skb(MAX_REG_IN_BUF_SIZE, GFP_ATOMIC); - if (!nskb) { + skb = alloc_skb(MAX_REG_IN_BUF_SIZE, GFP_ATOMIC); + if (!skb) { dev_err(&hif_dev->udev->dev, "ath9k_htc: REG_IN memory allocation failure\n"); - urb->context = NULL; - return; + goto free_rx_buf; } - rx_buf->skb = nskb; + rx_buf->skb = skb; usb_fill_int_urb(urb, hif_dev->udev, usb_rcvintpipe(hif_dev->udev, USB_REG_IN_PIPE), - nskb->data, MAX_REG_IN_BUF_SIZE, + skb->data, MAX_REG_IN_BUF_SIZE, ath9k_hif_usb_reg_in_cb, rx_buf, 1); }
@@ -762,12 +763,13 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb) ret = usb_submit_urb(urb, GFP_ATOMIC); if (ret) { usb_unanchor_urb(urb); - goto free; + goto free_skb; } return; -free: +free_skb: kfree_skb(skb); +free_rx_buf: kfree(rx_buf); urb->context = NULL; }
--
2.25.1