CVE-2022-49667

In the Linux kernel, the following vulnerability has been resolved:

net: bonding: fix use-after-free after 802.3ad slave unbind

commit 0622cab0341c ("bonding: fix 802.3ad aggregator reselection"), resolve case, when there is several aggregation groups in the same bond. bond3adunbind_slave will invalidate (clear) aggregator when _aggactiveports return zero. So, adclearagg can be executed even, when numofports!=0. Than bond3adunbindslave can be executed again for, previously cleared aggregator. NOTE: at this time bond3adunbindslave will not update slave ports list, because lagports==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 adclearagg().

The KASAN logs are as follows:

[ 767.617392] ================================================================== [ 767.630776] BUG: KASAN: use-after-free in bond3adstatemachinehandler+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: lacp1 bond3adstatemachinehandler [ 767.666468] Call trace: [ 767.668930] dumpbacktrace+0x0/0x2d0 [ 767.672625] showstack+0x24/0x30 [ 767.675965] dumpstacklvl+0x68/0x84 [ 767.679659] printaddressdescription.constprop.0+0x74/0x2b8 [ 767.685451] kasanreport+0x1f0/0x260 [ 767.689148] _asanload2+0x94/0xd0 [ 767.692667] bond3adstatemachinehandler+0x13dc/0x1470