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

[Brett Creeley]

On 12/13/2023 2:49 AM, Ke Xiao wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> 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.
>
> 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>
> ---
>   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..16b574d69843 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> @@ -108,11 +108,17 @@ static void netdev_hw_addr_refcnt(struct i40e_mac_filter *f,
>                                    struct net_device *netdev, int delta)
>   {
>          struct netdev_hw_addr *ha;
> +       struct netdev_hw_addr_list *ha_list;

Nit, needs to be in Reverse Christmas Tree (RCT) order.
>          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)
> --
> 2.17.1