Issue found during code review. This bug has no impact as long as the
ks8851_net structure is the first element of the ks8851_net_spi structure.
As long as the offset to the ks8851_net struct is zero, the container_of()
macro is subtracting 0 and therefore no damage done. But if the
ks8851_net_spi struct is ever modified such that the ks8851_net struct
within it is no longer the first element of the struct, then the bug would
manifest itself and cause problems.
struct ks8851_net is contained within ks8851_net_spi.
ks is contained within kss.
kss is the priv_data of the netdev structure.
Signed-off-by: Jerry Ray <[email protected]>
---
drivers/net/ethernet/micrel/ks8851_spi.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/micrel/ks8851_spi.c b/drivers/net/ethernet/micrel/ks8851_spi.c
index 479406ecbaa3..13c76352ae8d 100644
--- a/drivers/net/ethernet/micrel/ks8851_spi.c
+++ b/drivers/net/ethernet/micrel/ks8851_spi.c
@@ -413,7 +413,8 @@ static int ks8851_probe_spi(struct spi_device *spi)
spi->bits_per_word = 8;
- ks = netdev_priv(netdev);
+ kss = netdev_priv(netdev);
+ ks = &kss->ks8851;
ks->lock = ks8851_lock_spi;
ks->unlock = ks8851_unlock_spi;
@@ -433,8 +434,6 @@ static int ks8851_probe_spi(struct spi_device *spi)
IRQ_RXPSI) /* RX process stop */
ks->rc_ier = STD_IRQ;
- kss = to_ks8851_spi(ks);
-
kss->spidev = spi;
mutex_init(&kss->lock);
INIT_WORK(&kss->tx_work, ks8851_tx_work);
--
2.17.1
Hello:
This patch was applied to netdev/net-next.git (master)
by David S. Miller <[email protected]>:
On Mon, 22 Aug 2022 16:39:32 -0500 you wrote:
> Issue found during code review. This bug has no impact as long as the
> ks8851_net structure is the first element of the ks8851_net_spi structure.
> As long as the offset to the ks8851_net struct is zero, the container_of()
> macro is subtracting 0 and therefore no damage done. But if the
> ks8851_net_spi struct is ever modified such that the ks8851_net struct
> within it is no longer the first element of the struct, then the bug would
> manifest itself and cause problems.
>
> [...]
Here is the summary with links:
- micrel: ksz8851: fixes struct pointer issue
https://git.kernel.org/netdev/net-next/c/fef5de753ff0
You are awesome, thank you!
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