Re: [PATCH net V2] macsec: Fix use-after-free while sending the offloading packet

[Simon Horman <horms@kernel.org>]

On Mon, Oct 21, 2024 at 01:03:09PM +0300, Tariq Toukan wrote:
> From: Jianbo Liu <jianbol@nvidia.com>
> 
> KASAN reports the following UAF. The metadata_dst, which is used to
> store the SCI value for macsec offload, is already freed by
> metadata_dst_free() in macsec_free_netdev(), while driver still use it
> for sending the packet.
> 
> To fix this issue, dst_release() is used instead to release
> metadata_dst. So it is not freed instantly in macsec_free_netdev() if
> still referenced by skb.
> 
>  BUG: KASAN: slab-use-after-free in mlx5e_xmit+0x1e8f/0x4190 [mlx5_core]
>  Read of size 2 at addr ffff88813e42e038 by task kworker/7:2/714
>  [...]

...

> Fixes: 0a28bfd4971f ("net/macsec: Add MACsec skb_metadata_dst Tx Data path support")
> Signed-off-by: Jianbo Liu <jianbol@nvidia.com>
> Reviewed-by: Patrisious Haddad <phaddad@nvidia.com>
> Reviewed-by: Chris Mi <cmi@nvidia.com>
> Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
> ---
>  drivers/net/macsec.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> V2:
> - Removed NULL check before call to dst_release().

Thanks Jianbo, all, for the update.

Reviewed-by: Simon Horman <horms@kernel.org>

Please do follow up on the unencrypted packet issue flagged
by Sabrina in her review of v1 [1].

https://lore.kernel.org/all/Zw6CntwUyqM6CivS@hog/

...