CVE-2024-26951

In the Linux kernel, the following vulnerability has been resolved:
wireguard: netlink: check for dangling peer via is_dead instead of empty
list If all peers are removed via wg_peer_remove_all(), rather than setting
peer_list to empty, the peer is added to a temporary list with a head on
the stack of wg_peer_remove_all(). If a netlink dump is resumed and the
cursored peer is one that has been removed via wg_peer_remove_all(), it
will iterate from that peer and then attempt to dump freed peers. Fix this
by instead checking peer->is_dead, which was explictly created for this
purpose. Also move up the device_update_lock lockdep assertion, since
reading is_dead relies on that. It can be reproduced by a small script
like: echo “Setting config…” ip link add dev wg0 type wireguard wg
setconf wg0 /big-config ( while true; do echo “Showing config…” wg
showconf wg0 > /dev/null done ) & sleep 4 wg setconf wg0 <(printf
“[Peer]\nPublicKey=$(wg genkey)\n”) Resulting in: BUG: KASAN:
slab-use-after-free in __lock_acquire+0x182a/0x1b20 Read of size 8 at addr
ffff88811956ec70 by task wg/59 CPU: 2 PID: 59 Comm: wg Not tainted
6.8.0-rc2-debug+ #5 Call Trace: <TASK> dump_stack_lvl+0x47/0x70
print_address_description.constprop.0+0x2c/0x380 print_report+0xab/0x250
kasan_report+0xba/0xf0 __lock_acquire+0x182a/0x1b20
lock_acquire+0x191/0x4b0 down_read+0x80/0x440 get_peer+0x140/0xcb0
wg_get_device_dump+0x471/0x1130