CVE-2024-26961 mac802154: fix llsec key resources release in mac802154_llsec_key_del
A use-after-free vulnerability in the Linux kernel's mac802154 module allows attackers to potentially execute code or escalate privileges via race conditions during key deletion.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-26961?
CVE-2024-26961 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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: <TASK> 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: [<ffffffff81dcfa62>] __kmem_cache_alloc_node+0x1e2/0x2d0 [<ffffffff81c43865>] kmalloc_trace+0x25/0xc0 [<ffffffff88968b09>] mac802154_llsec_key_add+0xac9/0xcf0 [<ffffffff8896e41a>] ieee802154_add_llsec_key+0x5a/0x80 [<ffffffff8892adc6>] nl802154_add_llsec_key+0x426/0x5b0 [<ffffffff86ff293e>] genl_family_rcv_msg_doit+0x1fe/0x2f0 [<ffffffff86ff46d1>] genl_rcv_msg+0x531/0x7d0 [<ffffffff86fee7a9>] netlink_rcv_skb+0x169/0x440 [<ffffffff86ff1d88>] genl_rcv+0x28/0x40 [<ffffffff86fec15c>] netlink_unicast+0x53c/0x820 [<ffffffff86fecd8b>] netlink_sendmsg+0x93b/0xe60 [<ffffffff86b91b35>] ____sys_sendmsg+0xac5/0xca0 [<ffffffff86b9c3dd>] ___sys_sendmsg+0x11d/0x1c0 [<ffffffff86b9c65a>] __sys_sendmsg+0xfa/0x1d0 [<ffffffff88eadbf5>] do_syscall_64+0x45/0xf0 [<ffffffff890000ea>] 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).
Weakness: CWE-416
Which versions are affected by CVE-2024-26961?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-26961?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2024-26961 being exploited?
There is no known exploitation of CVE-2024-26961 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-40481, BELL-CVE-2024-26961, DEBIAN-CVE-2024-26961, GHSA-7533-c28p-jp9p, UBUNTU-CVE-2024-26961.