CVE-2024-47696 RDMA/iwcm: Fix WARNING:at_kernel/workqueue.c:#check_flush_dependency
A use-after-free vulnerability in the Linux kernel RDMA/iwcm module can cause a deadlock and system crash during CM ID destruction.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-47696?
CVE-2024-47696 is a high-severity use after free vulnerability in Linux kernel, published on 21 Oct 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
RDMA/iwcm: Fix WARNING:at_kernel/workqueue.c:#check_flush_dependency
In the commit aee2424246f9 ("RDMA/iwcm: Fix a use-after-free related to destroying CM IDs"), the function flush_workqueue is invoked to flush the work queue iwcm_wq.
But at that time, the work queue iwcm_wq was created via the function alloc_ordered_workqueue without the flag WQ_MEM_RECLAIM.
Because the current process is trying to flush the whole iwcm_wq, if iwcm_wq doesn't have the flag WQ_MEM_RECLAIM, verify that the current process is not reclaiming memory or running on a workqueue which doesn't have the flag WQ_MEM_RECLAIM as that can break forward-progress guarantee leading to a deadlock.
The call trace is as below:
[ 125.350876][ T1430] Call Trace: [ 125.356281][ T1430] <TASK> [ 125.361285][ T1430] ? __warn (kernel/panic.c:693) [ 125.367640][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.375689][ T1430] ? report_bug (lib/bug.c:180 lib/bug.c:219) [ 125.382505][ T1430] ? handle_bug (arch/x86/kernel/traps.c:239) [ 125.388987][ T1430] ? exc_invalid_op (arch/x86/kernel/traps.c:260 (discriminator 1)) [ 125.395831][ T1430] ? asm_exc_invalid_op (arch/x86/include/asm/idtentry.h:621) [ 125.403125][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.410984][ T1430] ? check_flush_dependency (kernel/workqueue.c:3706 (discriminator 9)) [ 125.418764][ T1430] __flush_workqueue (kernel/workqueue.c:3970) [ 125.426021][ T1430] ? __pfx___might_resched (kernel/sched/core.c:10151) [ 125.433431][ T1430] ? destroy_cm_id (drivers/infiniband/core/iwcm.c:375) iw_cm [ 125.441209][ T1430] ? __pfx___flush_workqueue (kernel/workqueue.c:3910) [ 125.473900][ T1430] ? _raw_spin_lock_irqsave (arch/x86/include/asm/atomic.h:107 include/linux/atomic/atomic-arch-fallback.h:2170 include/linux/atomic/atomic-instrumented.h:1302 include/asm-generic/qspinlock.h:111 include/linux/spinlock.h:187 include/linux/spinlock_api_smp.h:111 kernel/locking/spinlock.c:162) [ 125.473909][ T1430] ? __pfx__raw_spin_lock_irqsave (kernel/locking/spinlock.c:161) [ 125.482537][ T1430] _destroy_id (drivers/infiniband/core/cma.c:2044) rdma_cm [ 125.495072][ T1430] nvme_rdma_free_queue (drivers/nvme/host/rdma.c:656 drivers/nvme/host/rdma.c:650) nvme_rdma [ 125.505827][ T1430] nvme_rdma_reset_ctrl_work (drivers/nvme/host/rdma.c:2180) nvme_rdma [ 125.505831][ T1430] process_one_work (kernel/workqueue.c:3231) [ 125.515122][ T1430] worker_thread (kernel/workqueue.c:3306 kernel/workqueue.c:3393) [ 125.515127][ T1430] ? __pfx_worker_thread (kernel/workqueue.c:3339) [ 125.531837][ T1430] kthread (kernel/kthread.c:389) [ 125.539864][ T1430] ? __pfx_kthread (kernel/kthread.c:342) [ 125.550628][ T1430] ret_from_fork (arch/x86/kernel/process.c:147) [ 125.558840][ T1430] ? __pfx_kthread (kernel/kthread.c:342) [ 125.558844][ T1430] ret_from_fork_asm (arch/x86/entry/entry_64.S:257) [ 125.566487][ T1430] </TASK> [ 125.566488][ T1430] ---[ end trace 0000000000000000 ]---
Weakness: CWE-416
Which versions are affected by CVE-2024-47696?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-47696?
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-2024-47696 being exploited?
There is no known exploitation of CVE-2024-47696 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-50818, AZL-50949, BELL-CVE-2024-47696, DEBIAN-CVE-2024-47696, GHSA-36v8-3fmp-p728, UBUNTU-CVE-2024-47696.