CVE-2024-56556 binder: fix node UAF in binder_add_freeze_work()
A race condition in the Linux kernel binder driver allows a use-after-free, potentially enabling local attackers to escalate privileges or execute code.
- 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-2024-56556?
CVE-2024-56556 is a high-severity use after free vulnerability in Linux kernel, published on 27 Dec 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:
binder: fix node UAF in binder_add_freeze_work()
In binder_add_freeze_work() we iterate over the proc->nodes with the proc->inner_lock held. However, this lock is temporarily dropped in order to acquire the node->lock first (lock nesting order). This can race with binder_node_release() and trigger a use-after-free:
================================================================== BUG: KASAN: slab-use-after-free in _raw_spin_lock+0xe4/0x19c Write of size 4 at addr ffff53c04c29dd04 by task freeze/640
CPU: 5 UID: 0 PID: 640 Comm: freeze Not tainted 6.11.0-07343-ga727812a8d45 #17 Hardware name: linux,dummy-virt (DT) Call trace: _raw_spin_lock+0xe4/0x19c binder_add_freeze_work+0x148/0x478 binder_ioctl+0x1e70/0x25ac __arm64_sys_ioctl+0x124/0x190
Allocated by task 637: __kmalloc_cache_noprof+0x12c/0x27c binder_new_node+0x50/0x700 binder_transaction+0x35ac/0x6f74 binder_thread_write+0xfb8/0x42a0 binder_ioctl+0x18f0/0x25ac __arm64_sys_ioctl+0x124/0x190
Freed by task 637: kfree+0xf0/0x330 binder_thread_read+0x1e88/0x3a68 binder_ioctl+0x16d8/0x25ac __arm64_sys_ioctl+0x124/0x190 ==================================================================
Fix the race by taking a temporary reference on the node before releasing the proc->inner lock. This ensures the node remains alive while in use.
Which versions are affected by CVE-2024-56556?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-56556?
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-2024-56556 being exploited?
There is no known exploitation of CVE-2024-56556 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as A-380855429, ASB-A-380855429, BELL-CVE-2024-56556, DEBIAN-CVE-2024-56556, GHSA-wccj-rqrc-g885, UBUNTU-CVE-2024-56556.