From: Yevhen Orlov yevhen.orlov@plvision.eu
commit 050133e1aa2cb49bb17be847d48a4431598ef562 upstream.
commit 0622cab0341c ("bonding: fix 802.3ad aggregator reselection"), resolve case, when there is several aggregation groups in the same bond. bond_3ad_unbind_slave will invalidate (clear) aggregator when __agg_active_ports return zero. So, ad_clear_agg can be executed even, when num_of_ports!=0. Than bond_3ad_unbind_slave can be executed again for, previously cleared aggregator. NOTE: at this time bond_3ad_unbind_slave will not update slave ports list, because lag_ports==NULL. So, here we got slave ports, pointing to freed aggregator memory.
Fix with checking actual number of ports in group (as was before commit 0622cab0341c ("bonding: fix 802.3ad aggregator reselection") ), before ad_clear_agg().
The KASAN logs are as follows:
[ 767.617392] ================================================================== [ 767.630776] BUG: KASAN: use-after-free in bond_3ad_state_machine_handler+0x13dc/0x1470 [ 767.638764] Read of size 2 at addr ffff00011ba9d430 by task kworker/u8:7/767 [ 767.647361] CPU: 3 PID: 767 Comm: kworker/u8:7 Tainted: G O 5.15.11 #15 [ 767.655329] Hardware name: DNI AmazonGo1 A7040 board (DT) [ 767.660760] Workqueue: lacp_1 bond_3ad_state_machine_handler [ 767.666468] Call trace: [ 767.668930] dump_backtrace+0x0/0x2d0 [ 767.672625] show_stack+0x24/0x30 [ 767.675965] dump_stack_lvl+0x68/0x84 [ 767.679659] print_address_description.constprop.0+0x74/0x2b8 [ 767.685451] kasan_report+0x1f0/0x260 [ 767.689148] __asan_load2+0x94/0xd0 [ 767.692667] bond_3ad_state_machine_handler+0x13dc/0x1470
Fixes: 0622cab0341c ("bonding: fix 802.3ad aggregator reselection") Co-developed-by: Maksym Glubokiy maksym.glubokiy@plvision.eu Signed-off-by: Maksym Glubokiy maksym.glubokiy@plvision.eu Signed-off-by: Yevhen Orlov yevhen.orlov@plvision.eu Acked-by: Jay Vosburgh jay.vosburgh@canonical.com Link: https://lore.kernel.org/r/20220629012914.361-1-yevhen.orlov@plvision.eu Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/bonding/bond_3ad.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/net/bonding/bond_3ad.c +++ b/drivers/net/bonding/bond_3ad.c @@ -2218,7 +2218,8 @@ void bond_3ad_unbind_slave(struct slave temp_aggregator->num_of_ports--; if (__agg_active_ports(temp_aggregator) == 0) { select_new_active_agg = temp_aggregator->is_active; - ad_clear_agg(temp_aggregator); + if (temp_aggregator->num_of_ports == 0) + ad_clear_agg(temp_aggregator); if (select_new_active_agg) { slave_info(bond->dev, slave->dev, "Removing an active aggregator\n"); /* select new active aggregator */