4.19-stable review patch. If anyone has any objections, please let me know.
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From: Toke Høiland-Jørgensen toke@redhat.com
[ Upstream commit 94745807f3ebd379f23865e6dab196f220664179 ]
Syzbot points out that skb_trim() has a sanity check on the existing length of the skb, which can be uninitialised in some error paths. The intent here is clearly just to reset the length to zero before resubmitting, so switch to calling __skb_set_length(skb, 0) directly. In addition, __skb_set_length() already contains a call to skb_reset_tail_pointer(), so remove the redundant call.
The syzbot report came from ath9k_hif_usb_reg_in_cb(), but there's a similar usage of skb_trim() in ath9k_hif_usb_rx_cb(), change both while we're at it.
Reported-by: syzbot+98afa303be379af6cdb2@syzkaller.appspotmail.com Signed-off-by: Toke Høiland-Jørgensen toke@redhat.com Signed-off-by: Kalle Valo quic_kvalo@quicinc.com Link: https://patch.msgid.link/20240812142447.12328-1-toke@toke.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/ath/ath9k/hif_usb.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c index 3aa915d215545..24059a5178a9d 100644 --- a/drivers/net/wireless/ath/ath9k/hif_usb.c +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c @@ -718,8 +718,7 @@ static void ath9k_hif_usb_rx_cb(struct urb *urb) }
resubmit: - skb_reset_tail_pointer(skb); - skb_trim(skb, 0); + __skb_set_length(skb, 0);
usb_anchor_urb(urb, &hif_dev->rx_submitted); ret = usb_submit_urb(urb, GFP_ATOMIC); @@ -756,8 +755,7 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb) case -ESHUTDOWN: goto free_skb; default: - skb_reset_tail_pointer(skb); - skb_trim(skb, 0); + __skb_set_length(skb, 0);
goto resubmit; }