CVE-2024-26961

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

mac802154: fix llsec key resources release in mac802154_llsec_key_del

mac802154_llsec_key_del() can free resources of a key directly without
following the RCU rules for waiting before the end of a grace period. This
may lead to use-after-free in case llsec_lookup_key() is traversing the
list of keys in parallel with a key deletion:

refcount_t: addition on 0; use-after-free.
WARNING: CPU: 4 PID: 16000 at lib/refcount.c:25 refcount_warn_saturate+0x162/0x2a0
Modules linked in:
CPU: 4 PID: 16000 Comm: wpan-ping Not tainted 6.7.0 #19
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:refcount_warn_saturate+0x162/0x2a0
Call Trace:

llsec_lookup_key.isra.0+0x890/0x9e0
mac802154_llsec_encrypt+0x30c/0x9c0
ieee802154_subif_start_xmit+0x24/0x1e0
dev_hard_start_xmit+0x13e/0x690
sch_direct_xmit+0x2ae/0xbc0
__dev_queue_xmit+0x11dd/0x3c20
dgram_sendmsg+0x90b/0xd60
__sys_sendto+0x466/0x4c0
__x64_sys_sendto+0xe0/0x1c0
do_syscall_64+0x45/0xf0
entry_SYSCALL_64_after_hwframe+0x6e/0x76

Also, ieee802154_llsec_key_entry structures are not freed by
mac802154_llsec_key_del():

unreferenced object 0xffff8880613b6980 (size 64):
comm “iwpan”, pid 2176, jiffies 4294761134 (age 60.475s)
hex dump (first 32 bytes):
78 0d 8f 18 80 88 ff ff 22 01 00 00 00 00 ad de x…….”…….
00 00 00 00 00 00 00 00 03 00 cd ab 00 00 00 00 …………….
backtrace:
[] __kmem_cache_alloc_node+0x1e2/0x2d0
[] kmalloc_trace+0x25/0xc0
[] mac802154_llsec_key_add+0xac9/0xcf0
[] ieee802154_add_llsec_key+0x5a/0x80
[] nl802154_add_llsec_key+0x426/0x5b0
[] genl_family_rcv_msg_doit+0x1fe/0x2f0
[] genl_rcv_msg+0x531/0x7d0
[] netlink_rcv_skb+0x169/0x440
[] genl_rcv+0x28/0x40
[] netlink_unicast+0x53c/0x820
[] netlink_sendmsg+0x93b/0xe60
[] ____sys_sendmsg+0xac5/0xca0
[] ___sys_sendmsg+0x11d/0x1c0
[] __sys_sendmsg+0xfa/0x1d0
[] do_syscall_64+0x45/0xf0
[] entry_SYSCALL_64_after_hwframe+0x6e/0x76

Handle the proper resource release in the RCU callback function
mac802154_llsec_key_del_rcu().

Note that if llsec_lookup_key() finds a key, it gets a refcount via
llsec_key_get() and locally copies key id from key_entry (which is a
list element). So it’s safe to call llsec_key_put() and free the list
entry after the RCU grace period elapses.

Found by Linux Verification Center (linuxtesting.org).

More information : https://git.kernel.org/stable/c/068ab2759bc0b4daf0b964de61b2731449c86531