[PATCH AUTOSEL 4.19 187/671] mt76: usb: fix possible memory leak in mt76u_buf_free

Sasha Levin
2020-01-16T17:01:28Z

From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>

[ Upstream commit cb83585e1121bd6d6c039cf09fa32380bf8b6258 ]

Move q->ndesc initialization before the for loop in mt76u_alloc_rx
since otherwise allocated urbs will not be freed in mt76u_buf_free
Double-check scatterlist pointer in mt76u_buf_free

Fixes: b40b15e1521f ("mt76: add usb support to mt76 layer")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/mediatek/mt76/usb.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireless/mediatek/mt76/usb.c
index 8d40e92fb6f2..dcf927de65f3 100644
--- a/drivers/net/wireless/mediatek/mt76/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/usb.c
@@ -273,10 +273,16 @@ EXPORT_SYMBOL_GPL(mt76u_buf_alloc);
void mt76u_buf_free(struct mt76u_buf *buf)
{
struct urb *urb = buf->urb;
+ struct scatterlist *sg;
int i;

- for (i = 0; i < urb->num_sgs; i++)
- skb_free_frag(sg_virt(&urb->sg[i]));
+ for (i = 0; i < urb->num_sgs; i++) {
+ sg = &urb->sg[i];
+ if (!sg)
+ continue;
+
+ skb_free_frag(sg_virt(sg));
+ }
usb_free_urb(buf->urb);
}
EXPORT_SYMBOL_GPL(mt76u_buf_free);
@@ -478,7 +484,8 @@ static int mt76u_alloc_rx(struct mt76_dev *dev)
nsgs = 1;
}

- for (i = 0; i < MT_NUM_RX_ENTRIES; i++) {
+ q->ndesc = MT_NUM_RX_ENTRIES;
+ for (i = 0; i < q->ndesc; i++) {
err = mt76u_buf_alloc(dev, &q->entry[i].ubuf,
nsgs, q->buf_size,
SKB_WITH_OVERHEAD(q->buf_size),
@@ -486,7 +493,6 @@ static int mt76u_alloc_rx(struct mt76_dev *dev)
if (err < 0)
return err;
}
- q->ndesc = MT_NUM_RX_ENTRIES;

return mt76u_submit_rx_buffers(dev);
}
--
2.20.1