CVE-2024-50296 net: hns3: fix kernel crash when uninstalling driver
A race condition in the hns3 network driver causes a kernel crash when uninstalling the driver while disabling VFs, leading to denial of service.
- 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-2024-50296?
CVE-2024-50296 is a medium-severity vulnerability in Linux kernel, published on 19 Nov 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:
net: hns3: fix kernel crash when uninstalling driver
When the driver is uninstalled and the VF is disabled concurrently, a kernel crash occurs. The reason is that the two actions call function pci_disable_sriov(). The num_VFs is checked to determine whether to release the corresponding resources. During the second calling, num_VFs is not 0 and the resource release function is called. However, the corresponding resource has been released during the first invoking. Therefore, the problem occurs:
[15277.839633][T50670] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 ... [15278.131557][T50670] Call trace: [15278.134686][T50670] klist_put+0x28/0x12c [15278.138682][T50670] klist_del+0x14/0x20 [15278.142592][T50670] device_del+0xbc/0x3c0 [15278.146676][T50670] pci_remove_bus_device+0x84/0x120 [15278.151714][T50670] pci_stop_and_remove_bus_device+0x6c/0x80 [15278.157447][T50670] pci_iov_remove_virtfn+0xb4/0x12c [15278.162485][T50670] sriov_disable+0x50/0x11c [15278.166829][T50670] pci_disable_sriov+0x24/0x30 [15278.171433][T50670] hnae3_unregister_ae_algo_prepare+0x60/0x90 [hnae3] [15278.178039][T50670] hclge_exit+0x28/0xd0 [hclge] [15278.182730][T50670] __se_sys_delete_module.isra.0+0x164/0x230 [15278.188550][T50670] __arm64_sys_delete_module+0x1c/0x30 [15278.193848][T50670] invoke_syscall+0x50/0x11c [15278.198278][T50670] el0_svc_common.constprop.0+0x158/0x164 [15278.203837][T50670] do_el0_svc+0x34/0xcc [15278.207834][T50670] el0_svc+0x20/0x30
For details, see the following figure.
rmmod hclge disable VFs ---------------------------------------------------- hclge_exit() sriov_numvfs_store() ... device_lock() pci_disable_sriov() hns3_pci_sriov_configure() pci_disable_sriov() sriov_disable() sriov_disable() if !num_VFs : if !num_VFs : return; return; sriov_del_vfs() sriov_del_vfs() ... ... klist_put() klist_put() ... ... num_VFs = 0; num_VFs = 0; device_unlock();
In this patch, when driver is removing, we get the device_lock() to protect num_VFs, just like sriov_numvfs_store().
Weakness: CWE-476
Which versions are affected by CVE-2024-50296?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2024-50296?
Apply the vendor's patch.
Is CVE-2024-50296 being exploited?
There is no known exploitation of CVE-2024-50296 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-53582, AZL-53664, BELL-CVE-2024-50296, DEBIAN-CVE-2024-50296, GHSA-m253-89wr-92m7, UBUNTU-CVE-2024-50296.