Re: [net PATCH v2] i40e: fix use-after-free in i40e_aqc_add_filters()

[Jacob Keller]

On 12/17/2023 11:08 PM, Ke Xiao wrote:
> Commit 3116f59c12bd ("i40e: fix use-after-free in
> i40e_sync_filters_subtask()") avoided use-after-free issues,
> by increasing refcount during update the VSI filter list to
> the HW. However, it missed the unicast situation.
> 
> When deleting an unicast FDB entry, the i40e driver will release
> the mac_filter, and i40e_service_task will concurrently request
> firmware to add the mac_filter, which will lead to the following
> use-after-free issue.
> 
> Fix again for both netdev->uc and netdev->mc.
> 

Thanks for fixing this!

Reviewed-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>

> BUG: KASAN: use-after-free in i40e_aqc_add_filters+0x55c/0x5b0 [i40e]
> Read of size 2 at addr ffff888eb3452d60 by task kworker/8:7/6379
> 
> CPU: 8 PID: 6379 Comm: kworker/8:7 Kdump: loaded Tainted: G
> Workqueue: i40e i40e_service_task [i40e]
> Call Trace:
>  dump_stack+0x71/0xab
>  print_address_description+0x6b/0x290
>  kasan_report+0x14a/0x2b0
>  i40e_aqc_add_filters+0x55c/0x5b0 [i40e]
>  i40e_sync_vsi_filters+0x1676/0x39c0 [i40e]
>  i40e_service_task+0x1397/0x2bb0 [i40e]
>  process_one_work+0x56a/0x11f0
>  worker_thread+0x8f/0xf40
>  kthread+0x2a0/0x390
>  ret_from_fork+0x1f/0x40
> 
> Allocated by task 21948:
>  kasan_kmalloc+0xa6/0xd0
>  kmem_cache_alloc_trace+0xdb/0x1c0
>  i40e_add_filter+0x11e/0x520 [i40e]
>  i40e_addr_sync+0x37/0x60 [i40e]
>  __hw_addr_sync_dev+0x1f5/0x2f0
>  i40e_set_rx_mode+0x61/0x1e0 [i40e]
>  dev_uc_add_excl+0x137/0x190
>  i40e_ndo_fdb_add+0x161/0x260 [i40e]
>  rtnl_fdb_add+0x567/0x950
>  rtnetlink_rcv_msg+0x5db/0x880
>  netlink_rcv_skb+0x254/0x380
>  netlink_unicast+0x454/0x610
>  netlink_sendmsg+0x747/0xb00
>  sock_sendmsg+0xe2/0x120
>  __sys_sendto+0x1ae/0x290
>  __x64_sys_sendto+0xdd/0x1b0
>  do_syscall_64+0xa0/0x370
>  entry_SYSCALL_64_after_hwframe+0x65/0xca
> 
> Freed by task 21948:
>  __kasan_slab_free+0x137/0x190
>  kfree+0x8b/0x1b0
>  __i40e_del_filter+0x116/0x1e0 [i40e]
>  i40e_del_mac_filter+0x16c/0x300 [i40e]
>  i40e_addr_unsync+0x134/0x1b0 [i40e]
>  __hw_addr_sync_dev+0xff/0x2f0
>  i40e_set_rx_mode+0x61/0x1e0 [i40e]
>  dev_uc_del+0x77/0x90
>  rtnl_fdb_del+0x6a5/0x860
>  rtnetlink_rcv_msg+0x5db/0x880
>  netlink_rcv_skb+0x254/0x380
>  netlink_unicast+0x454/0x610
>  netlink_sendmsg+0x747/0xb00
>  sock_sendmsg+0xe2/0x120
>  __sys_sendto+0x1ae/0x290
>  __x64_sys_sendto+0xdd/0x1b0
>  do_syscall_64+0xa0/0x370
>  entry_SYSCALL_64_after_hwframe+0x65/0xca
> 
> Fixes: 3116f59c12bd ("i40e: fix use-after-free in i40e_sync_filters_subtask()")
> Fixes: 41c445ff0f48 ("i40e: main driver core")
> Signed-off-by: Ke Xiao <xiaoke@xxxxxxxxxxxxxx>
> Signed-off-by: Ding Hui <dinghui@xxxxxxxxxxxxxx>
> Cc: Di Zhu <zhudi2@xxxxxxxxxx>
> Reviewed-by: Jan Sokolowski <jan.sokolowski@xxxxxxxxx>
> Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
> ---
> v2:
> - Order local variable declarations in Reverse Christmas Tree (RCT)
> 
> ---
>  drivers/net/ethernet/intel/i40e/i40e_main.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
> index 1ab8dbe2d880..d5633a440cca 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> @@ -107,12 +107,18 @@ static struct workqueue_struct *i40e_wq;
>  static void netdev_hw_addr_refcnt(struct i40e_mac_filter *f,
>  				  struct net_device *netdev, int delta)
>  {
> +	struct netdev_hw_addr_list *ha_list;
>  	struct netdev_hw_addr *ha;
>  
>  	if (!f || !netdev)
>  		return;
>  
> -	netdev_for_each_mc_addr(ha, netdev) {
> +	if (is_unicast_ether_addr(f->macaddr) || is_link_local_ether_addr(f->macaddr))
> +		ha_list = &netdev->uc;
> +	else
> +		ha_list = &netdev->mc;
> +
> +	netdev_hw_addr_list_for_each(ha, ha_list) {
>  		if (ether_addr_equal(ha->addr, f->macaddr)) {
>  			ha->refcount += delta;
>  			if (ha->refcount <= 0)