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NULL Pointer Dereference Affecting kernel-syms-azure package, versions <6.4.0-150600.8.20.1

Severity

 Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.04% (15th percentile)

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  • Snyk IDSNYK-SLES156-KERNELSYMSAZURE-8505557
  • published14 Dec 2024
  • disclosed13 Dec 2024
Report a new vulnerability Found a mistake?

Introduced: 13 Dec 2024

NewCVE-2024-50296  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade SLES:15.6 kernel-syms-azure to version 6.4.0-150600.8.20.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-syms-azure package and not the kernel-syms-azure package as distributed by SLES. See How to fix? for SLES:15.6 relevant fixed versions and status.

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().

CVSS Scores

version 3.1