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Subject[PATCH 4.19 65/89] mt76: fix array overflow on receiving too many fragments for a packet
Date
From: Felix Fietkau <nbd@nbd.name>

commit b102f0c522cf668c8382c56a4f771b37d011cda2 upstream.

If the hardware receives an oversized packet with too many rx fragments,
skb_shinfo(skb)->frags can overflow and corrupt memory of adjacent pages.
This becomes especially visible if it corrupts the freelist pointer of
a slab page.

Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/wireless/mediatek/mt76/dma.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -396,10 +396,13 @@ mt76_add_fragment(struct mt76_dev *dev,
struct page *page = virt_to_head_page(data);
int offset = data - page_address(page);
struct sk_buff *skb = q->rx_head;
+ struct skb_shared_info *shinfo = skb_shinfo(skb);

- offset += q->buf_offset;
- skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, offset, len,
- q->buf_size);
+ if (shinfo->nr_frags < ARRAY_SIZE(shinfo->frags)) {
+ offset += q->buf_offset;
+ skb_add_rx_frag(skb, shinfo->nr_frags, page, offset, len,
+ q->buf_size);
+ }

if (more)
return;

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