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

[Sokolowski, Jan]

>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;
> 
> 	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


Reviewed-by: Jan Sokolowski <jan.sokolowski@xxxxxxxxx>