This is a note to let you know that I've just added the patch titled
net: ll_temac: Make sure to free skb when it is completely used
to the 5.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-ll_temac-make-sure-to-free-skb-when-it-is-completely-used.patch
and it can be found in the queue-5.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6aa32217a9a446275440ee8724b1ecaf1838df47 Mon Sep 17 00:00:00 2001
From: Esben Haabendal <esben@xxxxxxxxxx>
Date: Fri, 18 Jun 2021 12:52:23 +0200
Subject: net: ll_temac: Make sure to free skb when it is completely used
From: Esben Haabendal <esben@xxxxxxxxxx>
commit 6aa32217a9a446275440ee8724b1ecaf1838df47 upstream.
With the skb pointer piggy-backed on the TX BD, we have a simple and
efficient way to free the skb buffer when the frame has been transmitted.
But in order to avoid freeing the skb while there are still fragments from
the skb in use, we need to piggy-back on the TX BD of the skb, not the
first.
Without this, we are doing use-after-free on the DMA side, when the first
BD of a multi TX BD packet is seen as completed in xmit_done, and the
remaining BDs are still being processed.
Cc: stable@xxxxxxxxxxxxxxx # v5.4+
Signed-off-by: Esben Haabendal <esben@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/xilinx/ll_temac_main.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -876,7 +876,6 @@ temac_start_xmit(struct sk_buff *skb, st
return NETDEV_TX_OK;
}
cur_p->phys = cpu_to_be32(skb_dma_addr);
- ptr_to_txbd((void *)skb, cur_p);
for (ii = 0; ii < num_frag; ii++) {
if (++lp->tx_bd_tail >= lp->tx_bd_num)
@@ -915,6 +914,11 @@ temac_start_xmit(struct sk_buff *skb, st
}
cur_p->app0 |= cpu_to_be32(STS_CTRL_APP0_EOP);
+ /* Mark last fragment with skb address, so it can be consumed
+ * in temac_start_xmit_done()
+ */
+ ptr_to_txbd((void *)skb, cur_p);
+
tail_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail;
lp->tx_bd_tail++;
if (lp->tx_bd_tail >= lp->tx_bd_num)
Patches currently in stable-queue which might be from esben@xxxxxxxxxx are
queue-5.12/net-ll_temac-fix-tx-bd-buffer-overwrite.patch
queue-5.12/net-ll_temac-make-sure-to-free-skb-when-it-is-completely-used.patch
